Pneumatik Training Course Hafner-Pneumatik

Transcription

1 Pneumatik Training Curse Hafner-Pneumatik

2 Chapter 1: Basic Cncepts f Pneumatics Right f authrship: The cntent f the training (wrding, drawings, pictures) are wned by the authr. Any utilizatin except fr individual use is allwed nly after permissin f the authr. Chapter 1: Basic cncepts f pneumatics Page 3-8 Chapter 2: The general design f a pneumatic system and Page 9-14 its cmpnents Chapter 3: Gruping and cnstructin f cntrl valves Page Chapter 4: Structure and functin f directinal valves Page Chapter 5: Schemes f directinal cntrl valves ISO-symbls Page Chapter 6: Explanatin f the Hafner Type Numbering System Page Chapter 7: The pneumatic cylinder part 1 Page Chapter 8: The pneumatic cylinder - part 2 Page Chapter 9: The basics f air preparatin Page Chapter 10: Air preparatin units Page Chapter 11: Valves and actuatrs with the NAMUR-interface Page

3 Chapter 1: Basic Cncepts f Pneumatics What is pneumatics? Pneumatics is the utilizatin f cmpressed air in science and industry in rder t perfrm mechanical wrk and cntrl. We can either talk abut pneumatics r pneumatic systems. In this curse we define pneumatics as the cntrl and transfer f pwer by using cmpressed air. Advantages and Disadvantages f Cmpressed Air Pneumatic systems have numerus advantages, the mst imprtant f which are: The medium, cmpressed air, can be easily extracted frm ur envirnment. There is n lack r shrtage f it. After usage the cmpressed air ges back t its riginal cnditin. It can be released int the envirnment. Air can be cmpressed flexibly. Therefre it is ideal fr absrbing shcks and vibratins. The distributin f cmpressed air can be easily handled with pipes and hses. Cmpressed air can be used in fire- and explsin-hazardus envirnment. Bth its pressure level and vlume can be regulated quite easily. Therefre the energy brught t the actuatr can als be cntrlled quite easily and within brad parameters. The usage f pneumatic cmpnents is easy as well as their maintenance. Their functinality is generally very reliable. Besides these advantages there are sme typical disadvantages: Cmpressed air depending n its applicatin needs sme preparatin, especially filtratin and drying. Because f pricy electric energy and the limited efficiency f cmpressrs, cmpressed air is a relatively expensive means f energy. Because f air's cmpressibility, the precise and lad-independent psitining f the actuatr(s) is nt pssible.

4 Chapter 1: Basic Cncepts f Pneumatics Physical Fundamentals and Units f Measurement (metric system) The SI-system f units is based n numerus basic and derived units f measurement. We d nt cver that in detail. [Internatinal System f Units, shrt SI (french): Système internatinal d unités] Units f measurement that are relevant in pneumatics: Meter m (length / distance) Kilgram kg (weight / mass) Secnd s (time) Kelvin K (temperature) Derived units that are used: Newtn N (frce) Pascal Pa (pressure) Frce Frce is any interactin that, when unppsed, will change the mtin f an bject. In ther wrds, a frce can cause an bject with mass t change its velcity (acceleratin, change f shape). Frce can als be described as a push r pull. It is a vectr quantity cnsisting f magnitude and directin. Symbl: F Unit: Newtn Unit symbl: N In SI-based units:

5 Chapter 1: Basic Cncepts f Pneumatics Pressure Pressure is the frce applied perpendicular t the surface f an bject per unit area ver which the frce is distributed. Symbl: P Unit: Pascal Unit symbl: Pa In SI-based units: Fr measuring pressure, the fllwing multipliers are cmmn: 1 kpa (Kilpascal) = 1,000 Pa 1 MPa (megapascal) = 1,000,000 Pa In pneumatics we nrmally use the unit bar. 1 bar = 100,000 Pa = 0.1 MPa = 0.1 N/mm 2 1 mbar = bar 1 nbar = bar In sme cuntries such as the USA r Great Britain the unit psi (punds per square inch) is als still in use. 1 psi = 0.07 bar (runded) Standard atmspheric pressure is the pressure f the air n sea-level, which equals 1 atm (atmsphere). 1 atm = 101,325 Pa = mbar (Millibar) r hpa (Hektpascal) This unit is nrmally used in meterlgy. Runded and precise enugh fr mst applicatins: 1 atm = 1 bar Excess pressure r gauge pressure is the value f pressure abve standard atmspheric pressure. It is als called relative pressure.

6 Chapter 1: Basic Cncepts f Pneumatics In case abslute pressure is measured, standard atmspheric pressure is included. The scale starts at 0 Pa = ttal vacuum. Abslute pressure = standard atmspheric pressure + gauge pressure (relative pressure) Expressins: P (a) : P (t) : Abslute pressure Excess/Gauge pressure -P (t) : Vacuum Examples: 6 bar excess pressure = 6 bar (t) 7 bar abslute pressure = 7 bar (a) 0.7 bar abslute pressure = 0.7 bar (a) r -0.3 bar (t) The expressins excess pressure and vacuum refer t a value larger r smaller than standard atmspheric pressure. There are different levels f vacuum: Standard atmspheric pressure Pa = bar = 1 bar Lw vacuum (rugh vacuum) 100 kpa... 3 kpa = 1 bar bar Medium vacuum 3 kpa mpa = 0.03 bar mbar High vacuum 100 mpa... 1 µpa = mbar nbar Ultra-high vacuum Extremely high vacuum Outer space Perfect vacuum 100 npa ppa < 100 ppa 100 µpa... < 3 fpa 0 Pa In pneumatics we use the unit bar fr vacuum as well as fr excess pressure. Unless there is any further indicatin, we nrmally wrk with excess pressure = relative pressure.

7 Chapter 1: Basic Cncepts f Pneumatics In practice: We will calculate the frce f a cylinder with a defined diameter at a specific pressure. Accrding t Pascal's law: p: Pressure [Pascal] F: Frce [N] A: Surface [m 2 ] Hw much frce des a cylinder with a diameter f 40 mm apply at a pressure f 6 bar? In rder fr us t use the crrect units f measurement, we will use the unit Mpa fr pressure. This cnfrms t N/mm 2. Fr the diameter we will use mm. Diameter f the pistn f the cylinder d = 40 mm The surface f the pistn is t be calculated as a circular area: In numbers: At a (relative) wrking pressure p = 6 bar = 0.6 Thus: In numbers: This is the theretical frce. In practice we have t take lsses due t frictin int cnsideratin (apprx. 5%). Thus: A cylinder with a pistn with the diameter f 40 mm at 6 bar pressure generates apprx. 716 N frce. This translates int the ability t lift apprx. 73 kg.

8 Chapter 1: Basic Cncepts f Pneumatics Hw much frce des the same cylinder generate int the ppsite directin (pulling its rd back in)? Due t the pistn rd itself, the surface t push the rd ut is larger than the surface t pull it back in. The missing surface hast t be deducted. D = diameter f pistn d = diameter f pistn rd (40 mm) (16 mm) After deducting 5% as lss fr frictin we find that the pulling frce f the same cylinder is apprx. 601 N, in cmparisn t the 716 N pushing frce.

9 Chapter 2: The General Design f a Pneumatic System and its Cmpnents The rute f cmpressed air frm its generatin t the cnsumer In pneumatics cmpressed air is utilized fr perfrming mechanical wrk and fr cntrl. In rder t d s we need different equipment t generate, treat and handle cmpressed air. The graph displays the rute f the envirnmental air frm the cmpressr t the cnsumer f cmpressed air: Air Air filter Particles (slid) Cmpressr W Engine E Air dryer Thermal energy Tank fr cmpressed air Including safety-valve and cndensate drain Generatin f cmpressed air Cmpressed air netwrk Air preparatin Filter, regulatr, lubricatr, starter valve Pneumatic tubes and fittings Valves Cntrl valves Actuatrs Cylinders W Cnsumer When designing a pneumatic system, typically the individual elements are distributed spatially depending n their task. Althugh they are spatially separated, they are still cnnected systematically.

10 Chapter 2: The General Design f a Pneumatic System and its Cmpnents Generatin and transprtatin f cmpressed air We will have a brief lk at the fllwing elements f pneumatic systems. Air filter The air filter is integrated int the intake f the cmpressr. It prevents large, plluting particles n the utside frm entering the air system. Thrugh filtratin, a majr prtin f unwanted particles can be kept ut f the system. Cmpressr The task f the cmpressr is t cmpress the air t the required pressure and in the required vlume. The engine cnsumes energy. The cmpressr transfrms this energy and stres it as cmpressed air. Unfrtunately lsses are severe. The screw cmpressr is the mst cmmn type. Pistn cmpressrs are used as well. Air Dryer and Pre-Filters When air is cmpressed it lses its ability t hld water. Therefre water remains when air is cmpressed. As this water, the cndensate, wuld be disturbing the fllwing prcesses, it needs t be remved frm the pneumatic system. In a s called refrigeratin dryer the water cndensates and can be remved. There are als absrptin dryers in which the water is absrbed by special materials. The cmpressed air is als regularly plluted by il frm the cmpressr r particles that have nt been caught by its intake filter. Thse can cause prblems in the pneumatic system, e.g. in the valves. Often times they are separated frm the cmpressed air by using a central filter unit. We will cver air preparatin in a later chapter f the curse in detail. Tanks Tanks are used fr string cmpressed air temprarily. The strage guarantees that the demand can be cvered securely. Often times yu can find a cndensate drain at the tank. The cndensate can then drain ff thrugh a valve. The drain is actuated manually r autmatically. Cmpressed Air Netwrk The task f the netwrk is t distribute the cmpressed air frm the cmpressr t the user(s). The size f its tubes is imprtant because it has a significant influence n the security f supply. In general: The lnger the tubes the bigger the lss f pressure due t frictin. The mre users are cnnected the bigger the rifice f the tubes needs t be. The Quality f Cmpressed Air

11 Chapter 2: The General Design f a Pneumatic System and its Cmpnents The peratinal safety f an air system is directly linked t the quality f the cmpressed air. In general: - A better = cleaner air increases the peratinal safety f the system as the risk f blckage and wear is reduced. - Please take int cnsideratin that the manufacturers f the cmpnents and devices cmmunicate the quality requirements fr the air in use. Air quality is standardized by ISO :2010. Cntaminants and purity classes the standard ISO Particles, il and water are the mst imprtant cntaminants in cmpressed air. Fr each f these three there are purity classes in the standard. ISO :2010 Particles Water Oil Class Maximum number f particles f the fllwing size [µm] / m³ f cmpressed air 0,1... 0,5 µm Cncentratin 0,5...1 µm µm [mg/m 3 ] Pressure dew pint C Cntent f liquid [g/m 3 ] Ttal cntent (liquid, aersl, gas) [mg/m 3 ] 0. By definitin f the user, less cntaminatin than class , , , , X > 10 - > 10 > 5 Purity classes in accrdance t standard ISO Fr example: ISO :2010 [4:3:3] Particles = class 4, water = class 3, il = class 3 High quality cmpressed air is (by definitin) 100% il free = class 0. Air f this quality is required in medical applicatins, the fd-industry and electrnic industry.

12 Chapter 2: The General Design f a Pneumatic System and its Cmpnents Let's nt frget air pllutin! When designing a cmpressed air system take envirnmental factrs int cnsideratin! Air pllutin is cncentrated when the air is cmpressed. Industries with high emissins in the neighburhd can be f severe impact. Other factrs such as a high cncentratin f zne can influence yur system and eventually harm seal materials as well. Never ignre climatic cnditins. The dryer has t be mre capable in a ht and humid envirnment. Therefre it is imprtant that we knw what kind f air is sucked int ur cmpressr we make sure that after cmpressing the air is dried, cleaned and ptential il is separated frm it we cnsider the influence f the envirnmental factrs (climate and pllutin) cmpnents with very high lads are lubricated where necessary.. in rder t guarantee a safe peratin. The mst imprtant elements at the machine-level The sketch exemplifies a pneumatic system at the machine-level: Cylinder Flw regulatrs Cntrl valve Air preparatin units, shrt-frm: FRL The individual elements are represented by ISO-symbls, which are cnnected with lines. They display the rute f the cmpressed air. In rder t get a better verview we psitin the air preparatin n the bttm and the actuatrs n the tp f the drawing. We can frm lgic grups f the elements as yu can see in the drawing abve: Air preparatin

13 Chapter 2: The General Design f a Pneumatic System and its Cmpnents Filter Pressure regulatr Lubricatr Switch-n valve Sft start Cntrl valves Directinal cntrl valves Other types f cntrl valves Lgic elements Flw cntrl valves, check-valves Flw cntrl valves, uni- r bidirectinal Exhaust flw-regulatrs Nn-return valves = check valves Functin fittings Actuatrs, cylinders Cylinders Rdless cylinders Rtary actuatrs Tubes and fittings T distribute cmpressed air and t cnnect different cmpnents Hafner-Pneumatik distributes its prducts under the fllwing grups and categries: HAFNER Valves

14 Chapter 2: The General Design f a Pneumatic System and its Cmpnents Cylinders Prcess Valves Air Preparatin Units Fittings Tubes We will study the functin f all these grups in later chapters.

15 Chapter 3: Gruping and cnstructin f cntrl valves Pneumatic valves cntrl pneumatic actuatrs such as cylinders, rtary actuatrs etc. The valves cntrl the directin, speed (by flw) and frce (by pressure) f the actuatr. We can frm the fllwing grups f valves by distinguishing between their functins: The ISO-symbl tells yu a valve's functin. By reading the symbl crrectly yu get hints f hw t use it. Cntrl f the effective directin f actuatrs Directinal cntrl valves These valves cntrl the actuatrs directly r they cntrl ther cntrl valves. Applicatin example: Cntrl f a duble acting cylinder by a 5/2-way hand-lever valve: Cntrl f the amunt f cmpressed air int / ut f the actuatr Flw regulatrs These valves limit the amunt f air flwing thrugh them. Applicatin example: We can add tw uni-directinal flw regulatrs t the example abve. They cntrl the speed f the cylinder by limiting the amunt f air that is exhausted frm it. Limiting the exhaust air is generally the better way in cmparisn t limiting the air-supply, since it results in a smther mvement f the pistn. Pressure regulatin Pressure regulatrs

16 Chapter 3: Gruping and cnstructin f cntrl valves These prducts keep the secndary pressure at a distinct level when the incming pressure is vlatile. As yu knw frm Chapter 1, pressure determines the frce f an actuatr. Please nte: The secndary pressure can nly g as high as the entry pressure. Applicatin example: We can add a pressure regulatr t the example abve. That way we can cntrl the maximum frce f the cylinder by regulating the maximum pressure f the system behind the pressure regulatr. A pressure gauge indicates the secndary pressure. Quick exhaust Quick exhaust valves These valves are designed t exhaust the air frm an actuatr quickly, which increases the speed f the pistn. Applicatin example: We can replace ne f the flw-regulatrs with a quick exhaust valve in the example abve. By ding s, the air in the chamber f the cylinder exhausts directly int the envirnment and the air des nt flw back thrugh the cntrl valve. This maximizes the pushspeed f the pistn. Lgic elements

17 Chapter 3: Gruping and cnstructin f cntrl valves These valves are nt used fr directly cntrlling actuatrs but t set up pneumatic cntrl systems. Typical elements are: AND, OR, YES, NO. With these functins taken frm the Blean algebra, mst (mathematical) prblems can be slved. Applicatin example: A single acting cylinder has t be cntrlled by either ne OR the ther f tw 3/2-way valves. In case yu want t make sure that the cylinder nly mves if BOTH 3/2-way valves are actuated, replace the OR-gate by an AND-gate. Nn-return valves = Check valves Check valves prvide a free flw int nly ne directin. If cmpressed air cmes frm the ppsite side, it is blcked. Applicatin example: In rder t save cmpressed air n a duble acting cylinder that is ding wrk in nly ne directin, the air-pressure that is needed t return the pistn can be reduced significantly. A secnd pressure regulatr is required fr that. This regulatr has t have a by-pass when the air exhausts frm the relevant cylinder-side. The ne-way by-pass is realized by using a check-valve. A typical applicatin f a check-valve is the cmbinatin with a flw-regulatr (see abve example). This prduct is called Uni-directinal flw regulatr. In ne directin the air can by-pass the regulatr, whereas in the ther directin the free flw is blcked and the air is frced t g thrugh the regulatr. General infrmatin n directinal cntrl valves Directinal cntrl valves are the mst imprtant elements f a pneumatic cntrl system.

18 Chapter 3: Gruping and cnstructin f cntrl valves In any fluid applicatin they are utilized t define the rute f the medium. They are used t cntrl cylinders r ther actuatrs. They can als cntrl the mvement and the directin f pneumatic mtrs r cntrl ther cntrl valves. Directinal cntrl valves are nt designed fr regulating pressure r flw. We can frm categries f directinal cntrl valves as fllws: By basic design Spl valves Pppet valves By actuatin Mechanically actuated Manually actuated Pneumatically actuated Electrically actuated (slenid valves) By the number f (stable) psitins One stable psitin: single slenid / single pilt valve r spring return valve. Tw stable psitins: duble slenid / pilt valve, lever valve indexed. 3-psitins valves. Flw in basic psitin Fr 2/2-way and 3/2-way valves with spring return Nrmally pen Nrmally clsed Fr 3/3-, 4/3- and 5/3-way valves Centre clsed Centre exhausted Centre pressurized By the number f prts / psitins 2/2-way (2 prts, 2 psitins)

19 Chapter 3: Gruping and cnstructin f cntrl valves 3/2-way (3 prts, 2 psitins) 3/3-way (3 prts, 3 psitins) 4/2-way (4 prts, 2 psitins nly ne exhaust prt) 5/2-way (5 prts, 2 psitins) 4/3-way (4 prts, 3 psitins nly ne exhaust prt) 5/3-way (5 prts, 3 psitins) The mst cmmn types are in bld. Besides the nes mentined abve there are mre pssibilities fr special applicatins (e.g. 5/4-way valves, 7/3-way valves,...) Basic design f directinal cntrl valves Let's have a lk at the basic difference between spl and pppet valves. One f the basic elements f any directinal cntrl valve is the valve bdy. The bdy hlds the parts f the valve tgether. The secnd imprtant element is the mving part(s), which blcks and pens prts, r cnnects tw r mre f them with each ther.

20 Chapter 3: Gruping and cnstructin f cntrl valves The clsing element can either be a spl r a valve disk. Therefre we distinguish between: Spl valves and Pppet valves. Spl valves In spl-valves the different prts are cnnected by axially mving a cylindrical spl. The drawings belw display the clsed and pen psitin f a spl valve. Pppet valves In a pppet valve a valve-disc is pushed nt the valve-seat. When the disc is released again, the valve pens. The drawings belw display the clsed and pen psitin f a pppet valve. Gruping directinal cntrl valves by mdes f actuatin Actuatin means the surce f energy which mves the clsing element (disc r spl): mechanically a part f a machine pushes nt a stem r a rller-lever f the valve manually a human being perates a knb r a lever pneumatically a pressure signal mves the spl r the disc

21 Chapter 3: Gruping and cnstructin f cntrl valves electrically / slenid the plunger f a slenid pens a pppet valve (lifts the disc n the seat) slenid pilt the plunger f a slenid pens a pppet valve, the mves a spl r a secnd (larger) disc. Slenid valves can be distinguished as: Direct acting valves The (pppet) valve is directly pened by electric energy. Pilted valves (slenid pilt spl valves) The main valve is generally a spl valve. The spl is driven by cmpressed air. This pilt air is cntrlled by a pppet valve. Part f the energy used t cntrl the valve is supplied by the medium. The methd f using the energy f the medium is nt nly used in spl valves. Pppet valves r diaphragm valves can be designed like that, t. Slenid valves with external pilt feed This functin is very similar t the slenid pilt valves. The difference is that it's nt the energy f the medium f the main valve which is used t mve the spl, but instead there is an additinal prt fr cmpressed air. The slenid system is separately supplied thrugh that. Valves are available with different numbers f (stable) psitins: One stable psitin As sn as the actuatin is gne (i.e. the pneumatic signal r electric energy is cut, the buttn is released) the spl r the disc is frced back int its basic psitin. This mvement can be pwered either by a mechanical spring r by the energy f the medium ( air spring ). Tw stable psitins Whenever the actuatin stps, the spl r disc stays in its current psitin until there is an actuatin int the ppsite directin.

22 Chapter 3: Gruping and cnstructin f cntrl valves 3 psitins valves The spl / disc can generate 3 different kinds f cnnectins f the prts (very rarely mre). Manually actuated valves can be designed with 3 stable psitins r in a way that the spl is driven int centre psitin by mechanical springs. Valves that are actuated in ther ways are nrmally nly available with a basic psitin. Descriptin number f prts and number f psitins: The fllwing will nly ffer a first glance at this tpic. Yu will receive mre infrmatin in a later chapter. The valve is called X/Y-way valve, where X represents the number f prts in the main valve and Y the number f psitns. Example: 3/2-way valve The valve has 3 prts and 2 psitins. Number f psitins Prts In Eurpe yu will find mstly 2/2-, 3/2-, 5/2- and 5/3-way valves. In the USA 4/2 and 4/3-way valves are cmmn. Applicatin examples, distinguishing between slenid valves: Direct acting slenid valve (e.g.: MH ) Basic design: pppet valve Cntrl: slenid - direct acting Number f prts / psitins: 3/2-way Stable psitin(s): ne, single slenid Basic psitin: nrmally clsed The electric energy cnsumed by the cil is directly used t pen the valve disc. Slenid-pilt valve (e.g.: MH )

23 Chapter 3: Gruping and cnstructin f cntrl valves Althugh there are basically 2 valves inside this prduct - the main valve and the pilt valve -, the characteristics f the main valve define the prduct. Basic design: Main valve = spl valve Pilt valve = pppet valve Cntrl: slenid-pilt Number f prts / psitins: 3/2-way Stable psitin(s): ne, single slenid Basic psitin: nrmally clsed The electric energy cnsumed by the cil is used t perate the plunger in the pilt valve. The energy fr the main valve is given by the medium. Slenid valve with external pilt feed (e.g.: MEH ) There are 2 valves inside this prduct as well. Once again the characteristics f the main valve define the prduct: Basic design: External pilt feed prt Main valve = spl valve Pilt valve = pppet valve Cntrl: slenid-pilt Number f prts / psitins: 3/2-way Stable psitin(s): ne, single slenid Basic psitin: nrmally clsed The electric energy cnsumed by the cil is used t perate the plunger in the pilt valve. The energy fr the main valve is fed int the valve thrugh an additinal prt in its head. Therefre the peratin f the spl is independent frm the medium's pressure applied t the main valve

24 Chapter 4: Structure and functin f directinal valves Structure and functin f directinal valves 1. Structure f direct acting slenid valves Direct acting slenid valves are typically pppet valves. The mvement f the valve disk pens and clses the rute f the medium. The graphic belw shws the crss sectin f an electrically actuated direct acting 3/2-way valve. Actuatin: electrically (slenid valve) The electric current generates a magnetic field which is used t lift the plunger in the peratr tube. Withut current the plunger is pushed dwn by a mechanic spring. In a 3-way valve the plunger has tw seals = valve discs, ne n the bttm and ne n the tp. They are marked in green. Cntrl type: direct acting The frce f the magnetic field is used t pen the valve. There is n ther surce f energy, including the medium. Stable psitins: ne The valve has ne stable psitin defined by the mechanic spring hlding the plunger. When the electric signal is applied the valve switches. Once it is absent, the valve switches back. Basic psitin: nrmally clsed Withut electric energy the media is blcked at prt 1, thus the valve is clsed. Number f prts and psitins: 3/2-way The valve has 3 prts and 2 psitins. Typical features f direct acting valves: Orifice size: DN 1,2 3 mm Operating pressure: PN up t 10 bar Nminal flw: QN l/min Prt sizes: M5, G1/8 and G1/4 Pwer cnsumptin: 3W / 5VA and mre This type f valve ffers a small rifice size at 10 bar. Therefre the flw is relatively lw. If a larger rifice size is required, the pwer cnsumptin increases at the same rate. Functin:

25 Chapter 4: Structure and functin f directinal valves Pressure supply is cnnected t prt 1. The frce f the spring pushes the valve disk nt the seat and clses prt 1. This frce has t be larger than the frce f the medium. In basic psitin the valve is pen frm prt 2 t 3. (This is the nrmal basic psitin f a 3/2 way nrmally clsed valve.) As sn as sufficient electric current is applied t the cil the valve disc is lifted frm the valve seat f prt 1. Simultaneusly a secnd valve disc clses the seat between prts 2 and 3. Therefre the medium is free t flw between 1 and 2. The rute between 2 and 3 is blcked. As sn as the electric current is absent, the valve switches back int basic psitin (1 clsed, pen frm 2 t 3). Imprtant! Direct acting slenid valves nly use the electric energy prvided t lift the plunger against the frce f the mechanic spring. Therefre this type is mainly used fr valves with smaller rifice size. The frce f the spring has t be larger than the frce f the medium belw the seat and the generated frce f the cil larger than the ne f the spring. Hw are direct acting valves with larger rifice sizes designed? The graph belw shws the crss sectin f an electrically actuated direct acting 2/2-way valve. The technical characteristics f this valve with large rifice size are: Operating pressure (max): PN 2,5 bar Nminal flw: QN l/min Prt size: G3/8 and G1/2 Pwer cnsumptin: 16W / 20VA Orifice size: DN 10 mm The pwer cnsumptin f this valve is 16W/20VA, which is relatively high. The heat emissin will be significant s the cil needs t be large. In rder t vercme the mechanics explained abve: The larger the rifice (DN) r the required pressure range, the strnger the spring needs t be in rder t clse the seat the design here is different: Pressure is nt applied belw the plunger but at the tp. Therefre the valve can wrk with a sfter (weaker) spring supprted by the frce f the medium. The applied electric frce needs t vercme these 2 frces (spring plus medium) in rder t pen the valve. As mentined abve the required amunt f electric energy is significant. We learn frm this example that if valves with a large rifice used at high pressure are required, we need t use a secnd surce f energy. This energy is typically cming frm the medium. 2. Structure f pilt perated spl valves

26 Chapter 4: Structure and functin f directinal valves Pilt perated valves (spl valves) cnsist f 2 parts. The graphic belw shws the crss sectin f a 5/2- way single slenid valve. The pilt valve is a 3/2-way pppet valve. The main valve is a 5/2-way spl valve. The characteristics f the main valve are: Basic design: spl valve The axial mvement f the spl pens and clses the rute between distinct prts in the valve. This mvement is prvided by the energy f the cmpressed air. Actuatin: electrically (slenid valve) The pilt valve is electrically actuated. Fr its functin see the explanatin abve. Cntrl: pilted The pilt valve cntrls the pilt air which is taken frm prt 1 f the main valve and internally supplied t the pilt valve. Prt 2 f the pilt valve is cnnected t the tp f the spl, triggering its mvement. Number f stable psitins: ne The valve has ne stable psitin. As sn as the electric signal is absent, the pilt valve exhausts and the spl is pushed int basic psitin by either a mechanic spring r the frce f the medium feed frm prt 1 f the main valve t the back-end f the spl (called air spring). Smetimes a cmbinatin f bth types f springs is used. Basic psitin: Typically a 5/2-way valve is pen frm 1 t 2 and frm 4 t 5. There is n such thing as nrmally clsed r nrmally pen fr 5-way valves. Number f prts and psitins: 5/2, the valve has 5 prts and 2 psitins. The typical features f Hafner spl valves are:

27 Chapter 4: Structure and functin f directinal valves Orifice: DN 3 18 mm Operating pressure: PN 10 bar Nminal flw: QN l/min Prt size: M5 G3/4 Medium: Cmpressed air Pwer cnsumptin: 3W / 5VA Spl valves can cmbine a high flw (large rifice size) at a significant maximum pressure (the standard is arund 10 bar, can be larger n request) with a lw pwer cnsumptin. In rder t functin crrectly, the valves require a minimum pressure. If there is less pressure applied t the valve, the spl might nt mve. In this case the frictin is t high. Overview f advantages and disadvantages: Directly actuated valve Small rifice Directly actuated valve Big rifice Pilted valve Big rifice Orifice / Flw small high high Max. Operating pressure high lw high Min. Operating pressure 0 0 > 0 Pwer cnsumptin small high small We will nw intrduce yu t the functin f 5-way slenid spl valves which are pilt perated and explain the advantages f the Hafner design. The graph belw shws the crss sectin f a 5/2-way single slenid pilt valve.

28 Chapter 4: Structure and functin f directinal valves Functin f a Hafner 5/2-way single slenid valve (type: MH 510 / MD 510 / MMD 510) Pressure is cnnected t prt 1. Thrugh an axial hle in the spl cmpressed air is fed twards ne end f the spl int the end-cap (right side in the drawing), there the air spring is built up. The spl is pushed int basic psitin. (Generally the valve can als be equipped with a mechanic spring). Simultaneusly the pilt valve is supplied with cmpressed air thrugh the pilt air duct (indicated in blue). The different sectins inside the bdy f the main valve are separated by seals pressing nt the spl (green). In basic psitin air is allwed t flw frm 1 t 2. Besides that prts 4 and 5 (exhaust prt) are cnnected. Prt 3 is clsed. The main valve is pilted by a direct acting 3/2-way nrmally clsed pppet valve that is supplied with air frm the main valve. As the cil sitting n the peratr tube is supplied with sufficient electric current the plunger is lifted. This pens the valve seat in the pilt valve and pilt air is fed t the left side f the spl. As the surface f the spl n that side is larger (apprximately duble) than n the spring side (right) the spl is mving twards the end cap. Result: The main valve switches. Air cnnected t prt 1 is nw free t flw t prt 4. Prts 2 and 3 are cnnected, 5 is clsed. When the current is taken away frm the cil, the plunger drps and clsing the seat in the pilt valve. Pilt air exhausts thrugh the peratr tube. The air spring becmes strnger than the ppsite side f the spl and switches the main valve back int basic psitin. Special features f Hafner valves with the swimming O-ring. By using high quality materials and mdern means f manufacturing we can ffer a range f prducts at high quality and with high reliability. Materials in use standard valves: Bdy: andized aluminum

29 Chapter 4: Structure and functin f directinal valves Spl: Stainless steel Operatr system: brass, stainless steel, FKM Inner parts: brass, POM, NBR Seals: NBR, FPM (FKM) HAFNER als ffers valves made frm ther materials r fr specific applicatins such as: Stainless steel valves Brass-free prducts Lw temperature valves (t -50 C) Pppet valves made frm plyamide Valves fr explsin hazardus envirnments (ATEX- apprved) Features f the sealing system with the swimming O-ring : There is n defrmatin f the seal during assemblage f the valve - they are allwed t mve independently within the brass cage. Withut air pressure there is n cntact pressure and, therefre, n frictin. This cnstructin als has cnsequences fr the seals f the valves in use. When switching a 5/2- way valve nly three f the five seals are expsed t pressure and applying frictin t the spl. Becasue f the lw frictin, there is very little wear n the seals. As frictin is lw when pressure is lw and frictin as well as sealing effect increases with pressure the valves switch safely at lw as well as at high pressure. Our custmers benefit frm high durability and extended lifetime, high flw cmbined with cmpact design as well as high reliability. Cmmunicatin f flw rates The Hafner catalgue cntains infrmatin abut the flw-rates f the valves l/min (liter per minute). The nminal flw is measured accrding t standard as fllws: Supply pressure p1=6 bar, back pressure 5 bar The flw f the air at Δp=1 bar is indicated after expanding the air frm 5 t 0 bar in l/min.

30 Chapter 4: Structure and functin f directinal valves Therefre the amunt f expanded cmpressed air is 5 times the vlume f the air that is actually flwing. Imprtant ntice! Sme manufacturers cmmunicate the maximum flw at maximum perating pressure. This value might be significantly higher. In case yu design yur pneumatic system fr significantly lwer pressure than 6 bar yu might want t use cmpnents with a bigger rifice. HAFNER Pneumatik ffers a very wide range f direct acting pppet valves and pilt perated spl valves with prt size M5 t G 3/4 and a nminal flw f up t l/min!

31 Chapter 5: ISO Schemes f directinal cntrl valves Schemes f directinal valves The descriptin f directinal valves is standardized by DIN ISO 121. IMPORTANT! The ISO symbls display nly the functin f the valves. They d nt give any further infrmatin abut the design, flw, rifice size, etc. Basics f the ISO symbls: Each psitin the valve can take is represented by a square. The number f squares tells yu the number f psitins the valve can take. The air pathways are represented by lines. The directin f the airflw is represented by an arrw. In case air flws in bth directins there is a duble arrw. Clsed prts are displayed as a T. The prts carry numbers. The numbers are nly shwn in the square with the basic psitin f the valve. The type f actuatin is als symblized. The ISO-symbl cntains infrmatin cncerning the stability f the psitins and the reset. Directinal valves number f prts and psitins The directinal valves are described by the numbers f prts in the main valve (excluding pilt prts) and the number f psitins the valve can take, [number f prts] / [number f psitns] Number f psitins fr example: 2 squares = 2 psitns 3 prts Number f prts In this case we speak f a 3/2 way valve (spken: three tw way valve). Each psitin f the valve is displayed in a square. The basic psitin is symblized by the numbers f the prts. Page 31

32 Chapter 5: ISO Schemes f directinal cntrl valves On the right hand side yu can see the basic psitin f a nrmally clsed 3/2- way valve. Prt 1 = pressure supply is clsed (blue). Prt 2 = wrking, in basic psitin cnnected t prt 3 = exhaust (red). Basic psitin r nrmal psitin drawn in green. The secnd square displays the actuated psitin f the valve. Valve has been actuated (actuatin elements nt shwn here). Prt 1 is cnnected t wrking prt 2 (blue). Exhaust prt 3 is clsed (black). Actuated psitn drawn in green. Symbls f the mst cmmn valves Nrmally clsed 2/2-way valve Nrmally pen Nrmally clsed 3/2-way valve Nrmally pen Page 32

33 Chapter 5: ISO Schemes f directinal cntrl valves 4/2-way valve 5/2-way valve 4/3-way valve Center clsed 5/3-way valve Center clsed Symbls f actuatin elements and resets Apart frm the squares shwing the valve's functin, the symbls fr its actuatin elements and elements t reset/return it are shwn n the left, respectively right side f them. Mechanically actuated, Actuatin by stem With spring reset Mechanically actuated, Actuatin by rller lever With air spring reset Mechanically actuated, Actuatin by rller lever with idle return With cmbined (mechanical) spring and air spring reset Page 33

34 Chapter 5: ISO Schemes f directinal cntrl valves Manually actuated, Actuatin with a push-buttn Manually actuated, Actuatin by a lever Manually actuated, Actuatin by a lever, indexed, 2 psitins Actuated by ft / ft valve Pneumatically actuated Electrically actuated, Direct actuated valve Electrically actuated, Slenid pilt valve Manual verride Pneumatically actuated, Differential pistn, dminating side Pneumatically actuated, Differential pistn. Page 34

35 Chapter 5: ISO Schemes f directinal cntrl valves Numbering f prts All the prts in the valve are cunted thrugh. The numbers indicate the functin f the prt. The numbers always appear n the square fr the valve's basic/nrmal psitin. In case we talk abut a valve with 2 stable psitins, the numbers are shwn fr the implicit standard psitin. Basic psitin = nrmal psitin is the psitin the valve is in withut actuatin. Pressure supply 1 P Wrking prt(s) 2, 4, (6) A, B, C Exhaust(s) 3, 5, 7 R, S, T Pilt prts(s) 10, 12, 14 X, Y, Z Examples: The fllwing lever- and pneumatically actuated valves allw airflw in bth directins (duble arrws). Manually actuated, 5/2-way valve, indexed Type e.g.: HVR Actuatin : manually (by a lever) 2 psitins, bth stable, indexed Number f pneumatic prts: 5 Thus: 5 prts, 2 psitins = 5/2-way valve Page 35

36 Chapter 5: ISO Schemes f directinal cntrl valves Pneumatically actuated 5/2-way valve, single pilt, mechanical spring reset Type e.g.: P Actuatin : pneumatically (with air) 2 psitins, ne stable (with spring reset) Number f pneumatic prts: 5 plus pilt prt 14 Thus: 5 prts, 2 psitins = 5/2-way valve Slenid-pilt 5/3-way valve, 2 springs center the spl. Center psitin clsed. Type e.g.: MH Actuatin : electrically (slenid-pilt) including manual verride. 3 psitins, ne stable (spring centered) Number f pneumatic prts: 5 Thus: 5 prts, 3 psitins = 5/3-way valve Page 36

37 Chapter 5: ISO Schemes f directinal cntrl valves General infrmatin n circuits Lking at the fllwing circuits yu can see ptential ways fr using different types f directinal valves. 2/2-way valves 2/2-way valves are fr pening and clsing. They blck the medium r let it pass. 2/2-way valves can be either nrmally clsed r nrmally pen. In the scheme belw tw 2/2-way slenid valves (S1 and S2) are used t cntrl a cylinder with spring return (single acting) C1. Withut actuatin bth slenid valves are clsed. In rder t mve the pistn rd t the uter psitin (right) S2 has t be actuated. Cmpressed air is flwing frm the surce thrugh S2 int the cylinder. In rder t mve the pistn rd t the ppsite psitin S2 needs t be de-energized and S1 has t be actuated. In case nne f the valves are actuated, the pistn rd stays in last psitin. (The symbl at the bttm displays an FRL-unit (filter, regulatr, lubricatr). The functins f cylinders as well as f air-preparatin units will be discussed in a later chapter.) Page 37

38 Chapter 5: ISO Schemes f directinal cntrl valves 3/2-way valves 3/2-way valves are mstly used t cntrl single acting actuatrs. They can be nrmally clsed r nrmally pen. In the scheme belw yu can see tw applicatins. 1. An electrically actuated 3/2-way valve (S1) cntrls the single acting cylinder (C1). When the valve is actuated, air flws frm 1 t 2; the pistn rd f the cylinder is mving t uter psitin. When the valve is de-energized, it switches back t nrmal psitin and the mechanic spring in the cylinder drives the pistn rd back. 2. The duble acting cylinder (C2) is cntrlled by a 5/2-way valve (Y1). Valve Y1 is cntrlled by an electrically actuated, nrmally clsed 3/2-way valve (S2). Valve S2 is actuated (air flws frm prt 1 t prt 2). The air actuates valve Y1. It switches and air flws frm prt 1 t prt 4; the pistn rd f cylinder C2 mves t the uter psitin. As sn as valve S2 is de-energized, air exhausts frm prt 2 t 3. Valve Y1 switches back int nrmal psitin because f the built-in mechanic spring. Cmpressed air in valve Y1 flws frm 1 t 2 and the cylinder's exhaust frm 4 t 5 as the pistn rd mves back in. Page 38

39 Chapter 5: ISO Schemes f directinal cntrl valves 4/2-way and 5/2-way valves 4/2-way and 5/2-way, as well as 4/3-way and 5/3-way valves are usually used t cntrl duble acting actuatrs. In the example belw a manually actuated valve (S1 r S2) cntrls a duble acting cylinder (C1 r C2). Additinally, in rder t cntrl the speed f the cylinder, flw cntrl silencers are in use. The majr difference between the 4-way and the 5-way valve is that the 4-way valve ffers nly ne exhaust prt. Therefre the speed f the pistn rd mving in r ut cannt be cntrlled independently as the tw chambers f cylinder C1 are exhausted thrugh the same exhaust prt 3 f valve S1. As fr the 5/2-way valve (S2), the tw chambers n cylinder (C2) are exhausted thrugh separate exhaust prts (5 and 3). This ffers the pssibility t regulate the speed f the pistn rd independently. Page 39

40 Chapter 6: Explanatin f the Hafner type numbering system Review f previus chapters In the earlier chapters we intrduced yu t the mst imprtant characteristics f directinal valves. We have summarized them belw: Categrizing cntrl valves by the fllwing criteria (chapter 3): Basic design (spl valve, pppet valve) Actuatin (mechanically, manually, pneumatically r electrically actuated valves) Number f psitins (2-, 3-, 4-, 5-way) Number f prts (in cmbinatin with psitins) (2/2-way, 3/2-way, 5/2-way, 5/3-way, ) Nrmal psitin (fr 2/2-and 3/2-way valves: nrmally clsed r pen, fr 5/3-way valves: center clsed, exhausted, pressurized) By design (chapter 4) we have t distinguish between pppet and spl valves. It is imprtant t understand the difference in rder t select the right valve fr any applicatin. 2/2- r 3/2-way electrically and directly actuated pppet valves: directly cntrlled by the plunger f the slenid system. 3- r 5-way electrically actuated spl valves: cntrlled by an additinal pilt-valve Intrductin t directinal valves (chapter 5): ISO symbls and their meaning when it cmes t functin and psitins Numbering f their prts Page 40

41 Chapter 6: Explanatin f the Hafner type numbering system Explanatin f the Hafner type numbering system The HAFNER type numbers are a cmbinatin f letters and numbers, which carry further meaning. The mst imprtant characteristics f the valves are t be fund in the type number. The type number cntains 3 majr blcks (1-3) M H T explain the system we use the valve type MH G. This number has 3 main parts plus a suffix (blck 4, variable) the furth blck indicates a special variatin. The valve is defined by the 3 main blcks. The furth blck is there t indicate extra features, special materials etc. M H G Althugh there are sme exceptins, this standard cvers mst f the prducts. Blck 1 - actuatin The first letter defines the mde f actuatin f the valve Type M H B = Mechanically r manually actuated H = Hand lever valve P = Pneumatically actuated M = Slenid valve Page 41

42 Chapter 6: Explanatin f the Hafner type numbering system Type The next letter(s) give further infrmatin M H B = Mechanically r manually actuated BV = stem actuated valve BR = rller lever valve BL = rller lever valve with idle return BA = stem valve with cupling fr knb BH = push-pull valve H = Hand lever valve HV = with spring return (ne stable psitin) HVR = indexed HV(R)N = valve-bdy with interface fllwing NAMUR-standard P = Pneumatically actuated - n further infrmatin fr standard prducts PN = valve-bdy with NAMUR-interface M = Slenid valve MH = with manual verride t turn, nrmally clsed MD = mmentary manual verride t push, nrmally clsed MOH = nrmally pen MH valve (2/2 and 3/2-way) MOD = nrmally pen MD valve (2/2 and 3/2-way) MEH / MED = with external pilt feed MEOH = n.. and with external pilt feed MK = mdified MH-valve, with slenid MA16 (lw pwer cnsumptin 1.8W and fr valve terminals) This list is nt limited t the types mentined abve, but nly gives an verview abut the mst cmmn prducts. There are many mre. MNH / MND = valve-bdy with NAMUR-interface MNOH = valve-bdy with NAMUR-interface, nrmally pen Page 42

43 Chapter 6: Explanatin f the Hafner type numbering system Blck 2 The secnd blck cntains infrmatin abut the number f prts, the number f stable psitins and the type f spring. Number f prts in main valve M H The first digit displays the number f prts. 2 = 2-way = 2 prts (2/2) 3 = 3-way = 3 prts (3/2 r 3/3) 5 = 5-way = 5 prts (5/2 r 5/3) Psitins M H The secnd digit displays the number f psitins and whether the valve has ne r tw stable psitins. 1 = ne stable psitin (single sl. / pilt) 2 = tw stable psitins (duble sl. / pilt) 3 = 3-pstins ( _/3-way valves) Return M H In cmbinatin with the secnd digit (in this case 1 ), the third digit infrms abut the type f spring: 10 = air spring (n mechanic spring) 11 = mechanic spring inside, can als be executed as a cmbinatin f an air- with a mechanic spring. At duble slenid valves the third number is always a 0 as they dn t have any spring return. Center psitin fr 3-psitin valves (e.g. MH ) M H In case we are talking abut a 3-psitin valve, the third number defines the center psitin: 31 = Center clsed 32 = Center exhausted 33 = Center pressurized Page 43

44 Chapter 6: Explanatin f the Hafner type numbering system Blck 3 Blck 3 cntains infrmatin abut rifice size and prts. Orifice size M H The first digit(s) represent the rifice and thread size. 20 = DN 2 mm, prt: M5 30 = DN 3 mm, prt: M5 r G1/8" 34 = DN 3 mm, 4 mm push-in fitting Prts are BSP threaded by default. NPT threads are t be indicated by a NPT suffix in blck 4. The secnd digit in blck 3 defines the type f cnnectin: 0 = tapped wrking prts 2 and 4 4 = 4 mm push-in fitting(s) in prt(s) 2 and 4 40 = DN 4 mm, prt: G1/8" 46 = DN 4 mm, 6 mm push-in fitting 50 = DN 5 mm, prt: G1/8" 70 = DN 7 mm, prt: G1/4" 80 = DN 8 mm, prt: G1/4" 10 = DN 10 mm, prt: G3/8" 12 = DN 12 mm, prt: G1/2" 18 = DN 18 mm, prt: G3/4" 6 = 6 mm push-in fitting(s) in prt(s) 2 and 4 The rifice size als lets us knw abut the flw: 20 = DN 2 mm, flw: l/min 30 = DN 3 mm, flw: 280 l/min 40 = DN 4 mm, flw: 450 l/min 50 = DN 5 mm, flw: 650 l/min 70 = DN 7 mm, flw: 1250 l/min 80 = DN 8 mm, flw 1450 l/min 10 = DN 10 mm, flw: 2250 l/min 12 = DN 12 mm, flw: 3000 l/min 18 = DN 18 mm, flw: 6000 l/min Yu can get mre infrmatin abut flw frm the catalgue. Page 44

45 Chapter 6: Explanatin f the Hafner type numbering system Psitin f prts M H The last digit in blck 3 defines the psitin f the prts within the bdy: 1 = Standard, prts n bth sides f the valve 2 = All the prts n ne side 3 = Fr manifld-plates nly, supply and exhaust n ne side, wrking prts n ppsite side in the valve 4 = Fr manifld-plates nly, all the prts are in the plate. Standard (e.g. MH , MH ) All the prts n ne side (e.g. MH , MH ) Page 45

46 Chapter 6: Explanatin f the Hafner type numbering system On the fllwing fur pages we explain sme exemplary type numbers based n catalgue items: BV Blck 1 Actuatin: BV B = Mechanically actuated V = Stem Blck 2 First digit: number f prts = 3 Secnd digit: number f (stable) psitins = 1 Third digit: return = 1 = mechanic spring 3/2-way valve Mechanic spring return Blck 3 First and secnd digit: rifice size = 20 = rifice size 2 mm Third digit: psitin f the prts = 1 = standard M5 tapped prts (belngs t rifice size 2 mm) Prt 1 and 3 n ne side, wrking prt 2 n the ppsite side. Therefre the valve BV is a: Stem actuated valve 3/2-way with mechanic spring return M5-prts n bth sides f the valve, rifice size 2 mm Page 46

47 Chapter 6: Explanatin f the Hafner type numbering system HVR Blck 1 Actuatin: HVR H = Hand lever valve VR = Indexed (withut spring return) Blck 2 First digit: number f prts = 5 Secnd digit: number f (stable) psitins = 2 Third digit: return 0 = nn = 2 stable psitins 5/2-way valve 2 stable psitins Blck 3 First and secnd digit: rifice size = 70 = rifice size 7 mm Third digit: psitin f the prts = 1 = standard G 1/4 tapped prts (belngs t rifice size 7 mm) Prts 1, 3, 5 n ne side, wrking prts 2, 4 n the ppsite side. Therefre the valve HVR is a: Hand-lever valve 5/2-way indexed G 1/4 prts n bth sides f the valve, rifice size 7 mm Page 47

48 Chapter 6: Explanatin f the Hafner type numbering system MD DC Blck 1 Actuatin: MD M = Slenid valve D = Manual verride t push, mmentary Blck 2 First digit: number f prts = 5 Secnd digit: number f psitins = 3 Third digit (if secnd ne is a 3): center 1 = clsed 5/3-way valve Center clsed Blck 3 First and secnd digit: rifice size = 40 = rifice size 4 mm Third digit: psitin f the prts = 1 = standard G 1/8 tapped prts (belngs t rifice size 4 mm) Prts 1, 3, 5 n ne side, wrking prts 2, 4 n the ppsite side. Blck 4 (Misc.) 24DC fr MD and MK valves nly: vltage Therefre the valve MD DC is a: Slenid valve with manual verride t push 5/3-way center clsed G 1/8 prts n bth sides f the valve, rifice size 4 mm Integrated slenid 24V DC Page 48

49 Chapter 6: Explanatin f the Hafner type numbering system MNH Blck 1 Actuatin: MNH M = Slenid valve N = NAMUR-interface H = Manual verride t turn Blck 2 First digit: number f prts = 3 Secnd digit: number f (stable) psitins = 1 Third digit: return = 1 = mechanic spring inside (in this case a cmbined spring). 3/2-way valve Nrmally clsed With cmbined mech.-pneum. spring Blck 3 First and secnd digit: rifice size = 70 = rifice size 7 Third digit: psitin f the prts = 1 = standard, in cmbinatin with the N in Blck 1 with NAMUR-interface. G 1/4 tapped prts (belngs t rifice size 7 mm) Prts 1, 3, 5 n ne side, wrking prts in accrdance t NAMUR-standard (VDI/VDE 3845) Therefre the valve MNH is a: Slenid valve with manual verride t turn 3/2-way n.c. NAMUR-interface and prts 1, 3, 5 G 1/4, rifice size 7 mm Page 49

50 Chapter 6: Explanatin f the Hafner type numbering system As yu can see the HAFNER type numbering system is fllwing a standard that allws yu t understand what type f valve is in use r required whenever thse numbers are mentined. An verview abut the structure f the Hafner type numbers can als be fund n page 16 and 17 in the valve catalgue 2016: Page 50

51 Chapter 7: The pneumatic cylinder part 1 In the earlier chapters we lked at the basic design f a pneumatic system and its mst imprtant elements: Air preparatin Cntrl valves Flw-regulatrs Actuatrs / cylinders Tubes and fittings In this chapter we will be lking at pneumatic cylinders. Cylinders are the mst imprtant means f actuatin in pneumatics. The cylinder transfers the energy that is stred in the cmpressed air int mvement. They can be classified by: Design Cylinders with pistn rds Rdless cylinders Diaphragm cylinders Rtary cylinders Mvement Linear Rtary = turning Functin Single-acting Duble-acting 3- r 4-psitins Cushining Adjustable, pneumatic cushining Flexible cushining Withut cushining There is a very wide variety f pneumatic cylinders. In this training we will nly fcus the mst cmmn nes. Cylinders with pistn rds Page 51

52 Chapter 7: The pneumatic cylinder part 1 Cylinders are available in different types and fllw different internatinal standards. Besides the nes that fllw standards there are als nn-standardized cylinders. Especially befre the standardizatin int DIN/ ISO nrms 6431 and 6432, there were numerus cylinder-types ffered by different manufacturers. Cmmn standard cylinders are: Mini cartridge cylinders Rund cylinders DIN ISO 6432 Prfile cylinders ISO VDMA (ld nrm: DIN ISO 6431) Cmpact cylinders ISO UNITOP Shrt strke cylinders Tie rd cylinders ISO Page 52

53 Chapter 7: The pneumatic cylinder part 1 We will lk at the fllwing characteristics: 1. Design 2. Diameter and strke 3. Mvement 4. Number f psitins 5. ISO symbls 6. Cushining chapter 8 7. Detectin f cylinder psitin (magnetic) chapter 8 8. Speed cntrl chapter 8 9. Internatinal Standards chapter 8 1. Design f a cylinder Mst f the cylinders with a pistn rd cntain the fllwing parts: a tube that is clsed n bth ends with a cap and head. Inside the tube seen belw a pistn rd mves with a drive pistn. The mvement f the pistn is triggered by cmpressed air, cntrlled by a directinal valve. The directin is defined by the chamber int which cmpressed air is allwed t flw inside the cylinder. The frce is transferred by the pistn rd. Cmpnents f a pistn rd cylinder: Page 53

54 Chapter 7: The pneumatic cylinder part 1 2. Diameter and strke Diameter and strke are the mst imprtant attributes f a cylinder. e.g. HAFNER Cylinder DIP: DIP 40/320 Type numbering system: DIP type f cylinder / design (DIP = ISO standard duble-acting cylinder adjustable cushining magnetic pistn) 40 diameter f the pistn [mm] 320 strke f the cylinder [mm] The diameter is actually the diameter f the pistn. The diameter f the cylinder defines its frce relative t the air-pressure. The strke tells us hw many millimetres the pistn and therefre the pistn rd can travel. Page 54

55 Chapter 7: The pneumatic cylinder part 1 If the strke is lng, the frces n the bearing between head and pistn rd are high. In rder t avid a defect we recmmend t select a larger diameter (cylinders with larger pistn diameters als ffer larger pistn rd diameters). In case f very lng strkes r radial frces we recmmend the use f a guide unit. Pictures: DIP cylinder with assembled guide unit Diameters and strkes are standardized, the mst cmmn values are: Pistn diameters [mm]: ø8 ø10 ø12 ø16 ø20 ø25 ø32 ø40 ø50 ø63 ø80 ø100 ø125 ø160 ø200 ø250 ø320 Strke lengths [mm]: The available diameters depend n, and are limited by, the type / standard. The availability f strkes n the ther hand is less limited. The maximum frce generated by a cylinder depends n: Operating pressure Diameter f the pistn Frictin f the inner parts As an example we calculate the frce f a cylinder DIL 40/320 at 6 bar. Page 55

56 Chapter 7: The pneumatic cylinder part 1 Pistn diameter: Surface f drive pistn: Operating pressure: Calculatin f the frce: Thus we have a theretical frce f 753,6 N. As a rule f thumb we can deduct 5% fr frictin. Therefre a cylinder with a pistn diameter f 40 mm, and an perating pressure f 6 bar, can exert a frce f apprx. 716 N. If we divide the frce by gravity (9,81 m/s 2 ), we find - in practice - that ur cylinder can hld a mass f abut 73 kg. CAUTION! We can nly hld the weight with this frce, we cannt mve it yet! If we want t mve a weight we have t (again) take gravity int cnsideratin. Only then ur cylinder is nt nly able t hld a weight but t perfrm wrk. Page 56

57 Chapter 7: The pneumatic cylinder part 1 3. The Mvement f a cylinder We call the tw end-psitins f a cylinder psitive / plus and negative / minus psitins. Therefre we als call the tw chambers inside the cylinder the plus and the minus chamber. Psitive mvement Negative mvement The psitin where the pistn rd is ut f the cylinder the furthest pssible is called the plus end-psitin. In rder t reach it, the plus chamber needs t be inflated. The minus end-psitin is psitined n the ppsite side; the minus chamber needs t be inflated. The cylinder cannt reach an end-psitin if the ppsite chamber is nt fully exhausted! 4. Stable psitins f a cylinder We distinguish between single-acting and duble-acting cylinders. In single-acting cylinders nly ne chamber is inflated with cmpressed air. Therefre wrk is perfrmed nly in ne directin by cmpressed air. Fr the mvement int the ppsite directin a mechanic spring is the surce f energy. The strke is limited by the length f the spring. In general single-acting cylinders ffer a relatively shrt strke. Tw different types f single-acting cylinders are available: Single-acting cylinder with base psitin minus (spring between head and pistn) Single-acting cylinder with base psitin plus (spring between cap and pistn) Page 57

58 Chapter 7: The pneumatic cylinder part 1 Duble-acting cylinders are driven in bth directins by cmpressed air. They are always used when wrk has t be perfrmed in bth directins r when the required strke is lnger than the available springs. There are different designs fr different applicatins: Duble-acting cylinder (standard design) Duble-acting cylinder with thrugh pistn rd (Cylinder has a pistn rd n bth ends) Page 58

59 Chapter 7: The pneumatic cylinder part 1 Duble-acting cylinder, guided / nn-rtating rd (integrated guide unit fr higher radial frces) Cylinders with nn-rtating pistn rds (If the applicatin des nt allw a rtatin f the pistn rd, either a rd that des nt have circular crss sectin r a duble pistn-rd is in use) Multi-psitin cylinders (Tw cylinders are assembled back t back. Thus 4 different strkes with different lengths are pssible.) Tandem cylinder (Target: Higher frce f the cylinder withut increasing its diameter. In rder t achieve this, tw r mre cylinders are cnnected t each ther s that their pistn rds are cnnected as well and wrking in line. In ther wrds several pistns use the same pistn rd. Thus the frce adds up.) Page 59

60 Chapter 7: The pneumatic cylinder part 1 5. ISO symbls In rder t distinguish between cylinders, there are als well defined ISO symbls and schemes indicating their different functins. These d nt hwever indicate their size, diameter, strke, ISO-standard etc. Duble-acting cylinder ( standard design ) Duble-acting cylinder with magnetic pistn The pistn is different frm figure 1, indicating the magnetic pistn. Duble-acting cylinder with adjustable cushining Cushining symblized by tw rectangular bjects; arrw fr adjustable. Duble-acting cylinder with adjustable cushining and magnetic pistn Cmbinatin f figure 2 and 3. Duble-acting cylinder with thrugh pistn rd, adjustable cushining and magnetic pistn The thrugh pistn rd is added. Single-acting cylinder (MINUS) Single-acting cylinder with spring in minus chamber Single-acting cylinder (PLUS) Single-acting cylinder with spring in Plus chamber Page 60

61 Chapter 7: The pneumatic cylinder part 1 We intrduced the fllwing expressins: Cushining Magnetic pistn Their explanatin will fllw in the next chapter. Just t give yu a shrt insight: The adjustable cushining slws the cylinder dwn when the pistn is entering either head r cap. The idea is t avid a hard shck when the pistn hits these elements. The magnetic pistn is required if we want t check the psitn f the pistn with a REED-switch. The switch is added nt the utside f the cylinder. When the pistn travels by, the switch sends a signal. Page 61

62 Chapter 8: The pneumatic cylinder part 2 In chapter 7 we lked at the mst imprtant features and characteristics f a pneumatic cylinder: 10. Design 11. Diameter and strke 12. Mvement 13. Number f psitins 14. ISO symbls In this chapter we will cver: 15. Cushining 16. Detectin f cylinder psitin (magnetic) 17. Speed cntrl 18. Internatinal Standards 6. Cushining Cmpressed air can enter the cylinder at a very high speed. If the pistn hits the cap r head at high speed, it can lead t damage. In rder t avid that, mst cylinders are equipped with end-f-strke absrbers / cushining s, which reduce the pistn s speed shrtly befre it reaches the cap and thus reduce shck. There are tw ways t reduce the shck: flexible shck absrbers adjustable cushining Page 62

63 Chapter 8: The pneumatic cylinder part 2 Flexible Shck Absrbers The easiest way t avid a hard shck is t assemble sme kind f sft material between the pistn and the cap/head. It cmes in frm f a ring which is usually made frm plyurethane and thus ffers very gd shckabsrptin. This design is ften times used fr cylinders with rather small diameters where the strain is nt that high. The same kind is used fr cmpact cylinders where the small dimensins d nt allw any larger devices. The flexible shck absrbers are highlighted with red arrws in the graph belw. Adjustable (pneumatic) Cushining The adjustable pneumatic cushining is used if it cmes t strnger frces due t higher speeds r bigger sizes. This way f reducing shck is efficient as well as wear-free. During the last 10 t 50 mm f its travel (depending n the size f the cylinder), the pistn builds an air cushin inside the cylinder. The degree f cushining (= speed reductin) can be adjusted at bth ends f the cylinder fr bth sides respectively. The mechanism is a flw-regulating valve. Bth tie-rd and prfile cylinders ffer that feature, accrding t ISO Rdless cylinders ften ffer it, t. Rund cylinders (ISO 6432) f larger diameters, as well as special cylinders, can be equipped accrdingly. The cmpnents f the cushining are marked with red in the graph belw. Page 63

64 Chapter 8: The pneumatic cylinder part 2 Belw yu can learn mre abut the functin f the adjustable pneumatic cushining: 1. cylinder head 2. thrttle screw 3. cylinder tube 4. brake pistn 5. cylinder pistn 6. pistn rd 7. braking chamber 8. prt / air cnnectin graph 1. graph 2. During the mvement f the pistn, the cmpressed air exhausts thrugh the prt (8) (graph 1). Befre the pistn reaches the head, the brake pistn (4) which is part f the cylinder pistn (5) prevents the air within the braking chamber (7) frm exhausting thrugh the prt (8) (graph 2). The air trapped there can nly exhaust thrugh a much smaller rifice. The rifice can be adjusted with the thrttle screw. Inside the braking chamber (7) pressure ges up and generates a temprary air spring. Its resistance remains there until the air has cmpletely exhausted thrugh the thrttle screw (2). CAUTION! The thrttle screw can nly adjust the degree f cushining / speed f the cylinder pistn fr the last 10 t 50 mm f its mvement. Hw t adjust the speed f a cylinder in general will be cvered later in this chapter. Page 64

65 Chapter 8: The pneumatic cylinder part 2 7. Detectin f cylinder psitin (magnetic) Sensrs are abslutely necessary elements when it cmes t industrial autmatin. Sensrs generate infrmatin and cntrl entire prcesses. In rder t detect the psitin f the pistn, sensrs which are triggered by a magnetic field are assembled nt the pneumatic cylinder. The cylinder pistn is equipped with a magnet s that the sensr can receive a signal. The sensr is assembled nt the cylinder in the psitin where the signal is required. Many cylinders have an uter prfile that ffers space fr assembling the sensr directly. Sensr / switch assembled nt the tube There are tw different types f sensrs / switches: REED switch Inductive, PNP switch Page 65

66 Chapter 8: The pneumatic cylinder part 2 REED switch REED switches cnsist f tw ferrmagnetic nickel-irn wires. They are packed tgether in a glass tube filled with a nble gas and are made frm a magnetic material. The magnet in the pistn induces a magnetic field, making the shifting wires apprach each ther. The shifting wires cnnect and clse the electric circuit. The switches have an LED that starts t glw when the circuit is clsed. The REED switches have 2 wires, which can be perated between 3 and 230 Vlt AC/DC. Symbl Page 66

67 Chapter 8: The pneumatic cylinder part 2 Inductive, PNP switch The functin f the inductive PNP switch is based n the principles f a biplar junctin transistr. When the magnet that is built int the pistn gets clse t the switch, it gives a well-defined signal. The switch can be used nrmally pen as well as nrmally clsed. An LED displays the cnditin f the switch. PNP switches have generally 3 wires. They wrk within a vltage range f 5 t 30 V DC. Symbl Advantages f the PNP switch in cmparisn t the REED switch: N mvable parts inside Higher frequency Higher durability Page 67

68 Chapter 8: The pneumatic cylinder part 2 8. Speed cntrl f cylinders T cntrl the speed f a pneumatic cylinder (actuatr) ver the entire strke, flw regulatrs r flw-regulating silencers can be used. Fr the psitive mvement f a duble-acting cylinder, cmpressed air enters the plus chamber. Simultaneusly, the air in the minus chamber exits. (cntrlled by a 5/2-way valve) Ideally, we cntrl the speed f the cylinder by reducing the flw f the exiting air. T cntrl the speed, we regulate the exhaust air flwing ut f the cylinder chamber. We thereby avid an immediate exhaust. The air is in bth chambers available as lng as the pistn has reached the end psitin. The mvement is therefre very smth. CAUTION! In rder t set the speed f the cylinder and t get a smth mvement, it is always the exhaust air that has t be cntrlled. T d this there are different prducts available fr speed regulatin: Uni-directinal flw regulatr blck frm flw regulatr Uni-directinal flw regulatr functin fitting t be assembled in the cylinder Uni-directinal flw regulatr functin fitting t be assembled in the valve Exhaust flw regulatr t be assembled int the valve Page 68

69 Chapter 8: The pneumatic cylinder part 2 Uni-directinal flw regulatr = ne-way flw cntrl valve In rder t allw cmpressed air t flw int the cylinder at full speed, while allwing it t exhaust slwly, we use a ne-way flw cntrl valve. Thrttled air-flw: Air flwing this way has t pass the thrttle (flw regulatr) as the ther path is blcked by a check valve. Free air-flw: Air flwing the ppsite directin can bypass the thrttle and passes thrugh the check-valve (nnreturn valve). By using tw ne-way flw cntrl valves, we can independently regulate the psitive as well as the negative mvement f the cylinder. During psitive mvement, air bypasses the flw regulatr int the plus chamber. Air that is suppsed t leave the minus chamber has t pass thrugh the thrttle in the flw regulatr. This limits the speed f the cylinder. During negative mvement, the air flws thrugh the same blck frm flw regulatrs. This time the air flwing int the minus chamber bypasses the thrttle while the exhaust f the plus chamber is regulated. The speed f the psitive mvement has t be adjusted at the regulatr f the minus chamber and vice versa. There are many different designs f flw-regulatrs available and their sizes differ depending n the manufacturer. Page 69

70 Chapter 8: The pneumatic cylinder part 2 Functin fittings are screwed either directly int the cylinder r int the valve. Therefre there are tw different types, ne fr each area f applicatin. A flw regulatr fr a cylinder reduces the flw that streams frm the thread t the push-in fitting (ut f the cylinder). A flw regulatr fr a valve regulates the flw frm the push-in fitting t the threaded prt (int the valve). There are prducts where the manual adjustment can be dne with a screw-driver r with a knurled-head screw. Functin fitting with ne-way flw regulatr fr cylinder Functin fitting with ne-way flw regulatr fr valve One-way flw regulatr with tw push-in fittings Blck frm flw regulatr with tw female prts Page 70

71 Chapter 8: The pneumatic cylinder part 2 Sample circuits fr cylinders with speed cntrl Belw yu see three different ways f speed cntrl fr a duble-acting cylinder, with air supply via a jint FRL. Circuit 1 (Cylinder C1): The duble-acting cylinder C1 is cntrlled by the single slenid 5/2-way valve S1. As sn as the valve is actuated, air flws int the Plus chamber f the cylinder via F1.1. The air flw is nt restricted by F 1.1. Simultaneusly, air needs t exhaust frm the Minus chamber f the cylinder via F1.2. This flw is restricted by F1.2. Via the directinal valve S1 (prt 3), the air is finally exhausted. As sn as the electric actuatin f the directinal valve S1 is taken away, the valve switches back t nrmal psitin. Air flws at full speed via F1.2 int the Minus chamber f cylinder C1, while the air in the Plus chamber exits via F1.1 and S1, exhausting at prt 5 f S1. This flw is restricted by / adjusted at F1.1. The psitive mvement f the cylinder is regulated at F1.2, the negative mvement is restricted at F1.1. F1.1. and F1.2. can be screwed either int the cylinder r the valve, but the crrect versin has t be selected either way! Circuit 2 (Cylinder C2): The duble-acting cylinder C2 is cntrlled by the single slenid 5/2-way valve S2. The speed f the cylinder is adjusted at flw cntrl silencers F2.1 and F2.2., which are screwed int the valve. Fr psitive mvement, the directinal valve S2 needs t be actuated. Air streams at full speed frm prt 1 t prt 4 f the valve and int the Plus chamber f cylinder C2. At the same time air needs t exhaust frm the Minus chamber f the cylinder. The air streams int prt 2 f the valve S2. Its flw is restricted by F2.2 befre leaving the valve S2 at prt 3. Fr negative mvement, the valve switches back int standard psitin. The Minus chamber is supplied via prt 2 f valve S2. The exhaust frm the Plus chamber is restricted by F2.1 in prt 5 f the valve S2. Circuit 3 (Cylinder C3): The duble-acting cylinder C3 is cntrlled by the single slenid 5/2-way valve S3. Fr an extremely quick psitive mvement after actuating the valve, the Minus chamber is exhausted by the quick exhaust valve F3.2.; the exhaust air des nt pass the directinal cntrl valve S3. Fr negative mvement, the valve S3 needs t switch back int nrmal psitin. The exhaust air f the Plus chamber has t g thrugh the ne-way flw regulatr F3.1 Page 71

72 Chapter 8: The pneumatic cylinder part 2 9. Internatinal Standards The mst cmmn cylinders in pneumatics have been standardized, the target being maximum cmpatibility between prducts f different manufacturers. The mst cmmn cylinder standards are: ISO VDMA DIN ISO 6431 (ld standard) fr prfile and tie-rd cylinders. Page 72

73 Chapter 8: The pneumatic cylinder part 2 DIN ISO 6432 rund cylinders Page 73

74 Chapter 8: The pneumatic cylinder part 2 ISO cmpact cylinders Page 74

75 Chapter 8: The pneumatic cylinder part 2 UNITOP cmpact cylinders Page 75

76 Chapter 8: The pneumatic cylinder part 2 The HAFNER ISO cylinders The standard ISO is valid since The previus and very clsely related standard was ISO 6431 ( ). The standard defines pistn diameters (ø32...ø320 mm), maximum pressure (10 bar), and distinct features and dimensins, as well as standard accessries. Thus any accessries are als mstly interchangeable. The ISO cylinders in the HAFNER range have the type number DIL and DIP (fr prducts with a run- thrugh pistn rd: DBL and DBP) DIL cylinder The mre ecnmic slutin since little material is used fr the prfile. Easy t clean. Any sensrs have t be assembled with special fixing elements. DIP cylinder Switches can g int the grve, easy assembly, n additinal parts. Since 2016 HAFNER have been ffering anther range f ecnmically-priced prfile cylinders called H-series. HIF cylinder Switches can g int ne f the fur grves f the prfile tube. Page 76

77 Chapter 8: The pneumatic cylinder part 2 Materials used in an ISO cylinder f the D-series: # Descriptin Material 1. Cylinder cap Aluminum, andized 2. Fixing nut fr pistn Steel, nickel plated 3. O-Ring (seal between pistn and pistn rd ) NBR 4. Magnet Ferrmagnetic material 5. Pistn seal Plyurethane 6. Pistn Techn. plymer (r aluminum) 7. Tube Aluminum, andized 8. Guide Techn. plymer 9. O-Ring (seal fr cushining) NBR 10. Screw (fr cushining) Steel, nickel plated 11. Mbile seal (fr cushining) Plyurethane 12. Cylinder head Aluminum, andized 13. Screws Steel, nickel plated 14. Seal fr pistn rd Plyurethane 15. Pistn rd Chrmed steel r stainless steel 16. O-Ring (seal between head and tube / cap and NBR 17. Cvers PA 18. Bushing / bearing fr pistn rd Sintered bnze 19. Nut at pistn rd Steel, nickel plated Page 77

78 Chapter 8: The pneumatic cylinder part 2 Due t high speeds, lng strkes and high frequencies the seals can wear ut faster than ther parts. Therefre we ffer spare-part kits fr the cylinders. The spare-part kits cntain all ptentially wrn-ut parts. Repair kits fr cylinders types DIL, DIP, DBL and DBP have the rder cde DIR. Standard ISO als defines the dimensins f the fixed accessries. Therefre any accessries by different manufacturers will be mstly cmpatible. Page 78

79 Chapter 9: The basics f air preparatin Cmpressed air CAUTION! The quality f the cmpressed air in use is substantially imprtant fr the safe peratin and durability f the pneumatic system. Air cnsists f: Nitrgen (N 2 ) 78,09 %, Oxygen (O 2 ) 20,95% and Argn (Ar) 0,93 %. 0,03 % f the vlume is made up by ther gases,such as CO 2, Methane and varius nble gases. Air can be plluted by sulfurus gases, carbn-mnxides and dirt, damps, r particles. When prducing cmpressed air (cmpressing the envirnmental air), and when transprting it thrugh the tubes, ther harmful elements may enter. In rder t define the quality f cmpressed air, there are standardized purity classes. Purity classes fr cmpressed air in accrdance t ISO Cmpressed air is classified. The three mst imprtant elements f pllutin are particles, water and il. They are classified in accrdance t their degree f cncentratin within the air and displayed as fllws: ISO :2010 [A:B:C] A particles , X B water , X C il , X In case an element is displayed as class X (= an element with a high cncentratin), its amunt r the degree f cncentratin needs t be put in rund brackets. The fllwing example shws the quality f air where the water cncentratin is at Cw 15 g/m3. Therefre we indicate its purity as fllws: ISO :2010 [4:X(15):3] Page 79

80 Chapter 9: The basics f air preparatin Purity classes fr cmpressed air in accrdance t ISO ISO :2010 Particles Water Oil Class Maximum number f particles f the fllwing size [µm] / m³ f cmpressed air 0,1... 0,5 µm Cncentratin 0,5...1 µm µm [mg/m 3 ] Pressure dew pint C Cntent f liquid [g/m 3 ] Ttal cntent (liquid, aersl, gas) [mg/m 3 ] 0. By definitin f the user, less cntaminatin than class , , , , X > 10 - > 10 > 5 In nrmal pneumatic applicatins the fllwing air quality is sufficient: ISO :2010 [7:4:4]. Accrding t the ISO nrm, the permitted degrees f pllutin are: Particle cncentratin 5-10 mg/m 3 Dew pint less than 3 C Oil cncentratin max. 5 mg/m 3 Fr specific applicatins r in extreme envirnments (e.g. railway applicatin in cld climates), a higher air purity might be required. Page 80

81 Chapter 9: The basics f air preparatin Basics regarding the generatin and preparatin f cmpressed air When generating cmpressed air, it is imprtant t ensure it t be as il-free as pssible at the lwest pssible cst. The preparatin f cmpressed air has the same ecnmical aspect. It is pssible t generate cmpressed air f a high quality i.e. il-free r with reduced il-cntent with cmpressrs that wrk bth with and withut lubricatin if a sund air preparatin has been established. The envirnmental air and its quality The air's quality highly depends n external, envirnmental factrs. The cncentratin f hydr-carbnates due t industry r traffic can reach levels f 4-14 mg/m 3. In factries the il cntent can exceed 10 mg/m 3 because f clant and lubricatin fluids in the machinery. Mrever there are ther plluting elements such as sulfur dixide, st, metals, dust and humidity. Hw t define il-free cmpressed air? Accrding t ISO cmpressed air can be called il-free when the cntent f il (including il dust) is less than 0,01 mg/m 3. That is abut 4 % f the il cntent in nrmal air, s it is hardly detectable. Yu can find such requirements fr very high air purity e.g. in the fd and pharmaceutical industry as well as the electrnics industry (manufacture f wafers etc.). Where des humidity cme frm? There is always humidity in the envirnmental air. The degree f the humidity depends n temperature and air-pressure. The warmer it is, the higher the ability f air t hld water. At higher pressure that ability weakens. Abslute humidity: amunt f water in 1 m 3 air. Max. humidity (saturatin): highest pssible amunt f water in 1 m³ air at the given temperature and pressure. Relative humidity: the degree f humidity in relatin t max. humidity (%) at this temperature. Page 81

82 Chapter 9: The basics f air preparatin Frmula: The table belw displays the max. humidity values f air (saturatin values) at different temperatures: Temperature ( C) Water cntent (g/m 3 ) 0,4 0,7 1,1 1,6 2,4 3,4 4,8 6,8 9,4 12,8 17,3 23,1 30,4 39,6 51,2 If the humidity becmes higher than 100% relative humidity the excess water is released. The temperature at which water is released at the given air-water cncentratin is called the dew pint. Water is released when the temperature ges dwn and/r when air pressure rises. This is exactly what happens in the cmpressr as well as in the air-cler. The water that is released frms the s-called cndensate. The drying f cmpressed air When air gets cler, it releases water. Example: A screw cmpressr wrking at a temperature f 20 C, at sea-level, has a suctin capacity f 10 m 3 per minute; the relative humidity f the envirnmental air is 60 %. Lking at the table abve, we can see that at 20 C 100% humidity = 17.3 g water / m 3 air. S we can deduct that 60% humidity = 10.4 g water / m 3 Thus the 10 m³ cntains 104 g f water. At a cmpressin rati f 1:10 (10 bar), the cmpressr generates 1 m³ f cmpressed air per minute (10 m 3 envirnmental air = 1 m 3 cmpressed air). Page 82

83 Chapter 9: The basics f air preparatin During cmpressin the air's temperature rises t arund 80 C. At this temperature it can hld 290 g water / m 3 air (referring again t the table abve). Therefre its relative humidity is at nly 36% (104 / 290 = 36%). The air is relatively dry and prduces n cndensate. A cler after the cmpressr cls the cmpressed air dwn frm 80 C t apprx. 35 C. At 35 C the air can nly hld 39.6 g / m 3, thugh there are 104 g f water inside each m 3. S 64 g / m 3 will be released. This means we have 64 g f excess water every minute the cmpressr perates. This translates (x 60 x 8) int 31 liter f cndensate after an 8 hur shift. In rder t have fairly safe wrking cnditins, this cndensate needs t be remved. The drying ( = cling) f the generated cmpressed air is an essential part f the generatin and preparatin f cmpressed air. CAUTION! Withut prperly drying the air yu will find a lt f cndensate in the air-tank as well as in yur pipelines, machinery and many ther places. CAUTION! The standard filters f an FRL-unit ( ,01 Mikrn), d nt influence the cntent f water. They are made fr filtering particles. The water yu will find in the cndensate drain f a filter cnsists nly f a few drps. It is irrelevant in cmparisn t the amunts f water mentined befre. Hw t dry the air? The drying f cmpressed air in an industrial envirnment is usually achieved with ne f the fllwing methds: Deliquescent dryer A deliquescent dryer typically cnsists f a cntainer filled with hygrscpic material that absrbs the water. Advantage: N additinal energy is required. Disadvantage: The hygrscpic materials have t be replaced regularly. Desiccant dryer Als called twin twer dryer r adsrptin dryer. The air flws thrugh a desiccant material such as silica gel. The gel's ability t keep water is limited, but can be easily reset by blwing the water ut ( purging the gel). N additinal energy is required here either, but there is a lss f cmpressed air due t the purge. Large equipment is needed fr air flws at high speeds. Page 83

84 Chapter 9: The basics f air preparatin Membrane dryer First the air has t be filtered with a high quality calescing filter, then the air passes thrugh a center bre f a hllw fibre in a membrane bundle. Dryer air is flating utside the membrane. This leads t an exchange f vapr. Disadvantage: the flw is limited t arund 1000 l/min. Refrigerated dryer Refrigerated drying is based n the principle that clder air can hld less water. The air passes a heatexchanger that is cled t arund 3 C. The cled-dwn air lses water as well as il, bth f which are cllected. After drying the air is filtered. Cmpnents f a refrigeratin dryer 1. Air-in and air-ut 2. Air-t-air head exchanger 3. Air-t-refrigeratin heat exchanger 4. Cndensate separatr 5. Cndensate drain 6. Cling cmpressr 7. Cling ventilatr 8. Cling medium injectr Page 84

85 Chapter 9: The basics f air preparatin Why is air-preparatin necessary? Yu culd lk at a cmpressr as a big vacuum cleaner. It sucks in everything frm the envirnment. When generating cmpressed air, all the envirnmental elements f pllutin are cncentrated. Everything is fed int the pneumatic system. FRL-units are an imprtant element f the pneumatic system. With these units the air can reach the required quality since they have filters fr cleanness, lubricatin fr il cntent and can manage pressure. Well-prcessed air des nt nly ensure a safer wrkspace but als increases the durability f the equipment. Air preparatin equipment cnsists f: Filters Pressure regulatrs Lubricatrs Switch-n and starter valves Distributrs, pressure switches We can categrize them by design, size, flw rates and prt size. There is a wide range available, frm prt size G1/8" t G3". Page 85

86 Chapter 9: The basics f air preparatin The fllwing pictures shw a selectin f the mst cmmn elements: Filter Regulatr Lubricatr Filter-Regulatr Unit Page 86

87 Chapter 9: The basics f air preparatin FRL-unit, cnsisting f a filter, a regulatr and a lubricatr Mdular FRL-units ffer a high degree f flexibility t the user since these individual prducts can be assembled easily int a whle unit. Page 87

88 Chapter 10: Air Preparatin Units Filtering f cmpressed air The task f the filter is t filter ut particles and t remve the cndensate released by the cmpressed air. CAUTION! Filters (50 t 0,01 Micrn) have n influence n humidity, they filter particles depending n the fineness f the filter elements. The water that is fund in the cndensate drain nly cnsists f drps and is relatively irrelevant. Smetimes several filters are necessary in a system because f different requirements: Pllutin frm the pipeline r cndensate released during transprtatin has t be remved befre reaching individual equipment. Different pieces f cntrl r regulating equipment require different air quality. Fr specific applicatins (e.g. the packaging f fd) standard filtratin is insufficient. Activated-carbn filters are required. The air used in these filters has t be pre-filtered by fine-filters. In pneumatics cyclnic filtratin is ften used t separate particles and cndensate frm the medium. Cyclnic separatr 1. Filter bwl 2. Filter element 3. Bdy 4. Cndensate drain A high-speed rtating (air) flw is established within a cylindrical r cnical cntainer, called a cyclne. Due t the centrifugal frce, particles and cndensate fall twards the utside and drp t the bttm. In additin, the medium flws thrugh a filter element that catches smaller particles. The fineness f the filter element determines the max. size f particles. Plluted cndensate can be drained frm the bttm f the bwl. Page 88

89 Chapter 10: Air Preparatin Units An autmated drain valve wrks as a flating exhaust valve. As sn as the cndensate reaches a certain level, the valve pens and drains the bwl. Autmated cndensate drain 1. Flat sensr 2. Bdy 3. Spring 4. Clsing element 5. Bwl 6. Prt fr cndensate manual verride Hw it wrks: Withut pressure the clsing element (4) is in an pen psitin. The cndensate that is cncentrated at the bttm f the bwl (5) is drained. At an perating pressure f arund 1,5 bar the valve clses the drain. In case that during peratin (pressure in the filter element) the cndensate rises high enugh t lft the flater, the valve pens the drain and the cndensate is blwn ut f the bwl. Thus the level f cndensate is lwered and the drain clses again. Autmated drains can als be perated manually. By turning the knb at the bttm, the drain is n manual mde and the cndensate is blwn ut f the bwl (if there is air pressure) / drips ut f the bwl (withut air pressure). Page 89

90 Chapter 10: Air Preparatin Units Depending n the requirements inside the pneumatic system there are different filter elements ffering different degrees f fineness and materials. In pneumatics we typically use filter elements with a finesses f 5 t 50 µm. In rder t reach an air quality accrding t ISO :2010 [7:4:4], the fllwing is required: Cncentratin f particles: 5-10 mg/m 3 Filter fineness: µm In case f higher requirements, we recmmend standard ISO :2010 [6:4:4] which is still cmmn in pneumatics: Cncentratin f particles: Maximum 5 mg/m 3 Filter fineness: 5 µm Based n make and fineness f the filter element, we differentiate between filters: Classic filter unit Filter fineness: 5 µm, 20 µm, 50 µm Material: sintered PE, sintered brnze n request Pre-filter unit Filter fineness: 0,3 µm Material: cellulse-acetate Fine-filter unit Filter fineness: 0,01 µm Material: glass fibre with acetate Activated-carbn filter Material: activated-carbn Page 90

91 Chapter 10: Air Preparatin Units Classic filter unit Pre-filter unit Fine-filter unit Activated-carbn filter unit (KFIL) (KPFI) (KCFI) (KAFI) Filter fineness: 5 µm Filter fineness: 0,3 µm Filter fineness: 0,01 µm Filter fineness: n.a. Oil cntent: 0,1 mg/m 3 Oil cntent: 0,01 mg/m 3 Oil cntent 0,005 mg/m 3 Class 2 (ISO ) Class 1(ISO ) Class 0 (ISO ) Durability f the filter elements Filter elements need t be exchanged n a regular basis since their flw will be reduced ver time due t pllutin. The lss f air-pressure can be detected by measuring the differential pressure in frnt f and behind the filter. p = p 1 - p 2 Measuring differential pressure with a gauge: The dirtier the filter element, the larger the pressure drp inside the filter. The pressure difference is measured between 0 and 0,5 bar, which shws hw much blckage there is in the filter element. Page 91

92 Chapter 10: Air Preparatin Units Pressure regulatin with a regulatr Nrmally the netwrk supplies pressure between 6 and 10 bar, which can vary depending n the rate f air cnsumptin. In rder t use cmpressed air efficiently, the required pressure shuld be set fr each piece f equipment with an individual pressure regulatr. The individual pressure can nly be lwer than the pressure supplied by the netwrk. It is the task f the pressure regulating valve t hld the level f the utput pressure n a cnstant level, regardless f input pressure r fluctuatins in air cnsumptin. We differentiate between regulatrs with secndary venting and regulatrs withut secndary venting. Regulatrs with secndary venting can let ut excess pressure n the secndary side, e.g. when the pressure P2 is reduced by the peratr r when the pressure is increased by the equipment (high lad n a large cylinder). Regulatrs withut secndary venting are usually used when the medium is nt suppsed t be released int the atmsphere. Page 92

93 Chapter 10: Air Preparatin Units Regulatr, with secndary venting 1. Bdy spring casting 2. Knb t set pressure 3. Spring 4. Diaphragm 5. Seat with valve disc 6. Cunter-pressure spring 7. Bdy Essential fr the pressure regulatin is the diaphragm (4). On the surface belw the diaphragm, the secndary pressure is in effect, against which the frce f the set spring (2) wrks frm the tp. If the frce f the air pressure is weaker than that f the spring, the diaphragm is pushed dwn and the valve rd (5) is pening the pppet valve. Pressure is rising. In case there is less cnsumptin, pressure belw the diaphragm builds up. The frce f the air is larger than that f the spring, and the valve disc is gradually clsing, eventually fully clsing the valve seat. If secndary pressure exceeds the pressure that was set, the diaphragm is pushed upwards and the secndary exhaust is pening up (if the regulatr is equipped with a secndary vent). Secndary pressure can be displayed by a pressure gauge. CAUTION! Pressure regulatin in pneumatics is a regulatin f vlume. The amunt f cmpressed air behind the regulatr needs t be large enugh t build up an air pressure that is the same as set at the regulatr (ff-setting the frce f the spring in the regulatr). If the pressure drps, mre air is fed int the system behind the regulatr. There must be a balance between the frce f the air-pressure and the frce f the spring. Page 93

94 Chapter 10: Air Preparatin Units Lubricating the cmpressed air Neither cntrl-elements nr actuatrs are separately lubricated in a pneumatic system. In rder t avid wearut, lubricatin can help. Unnecessary frictin als increases energy cnsumptin. The gal f the manufacturers f the cmpnents is t design prducts that d nt require any individual lubricatin. This can be realized by selecting the right materials, chsing the right seal system, reducing frictin, r supplying the prduct with sufficient (life-lng) lubricatin when initially sld. Fr this kind f lubricatin, special types f grease are available. They are designed t cnstantly stay in the valves r cylinders. In rder fr the lubricant t avid washing-ut, the air needs t be dry since water has a negative effect n it as well. The same washing-ut effect is true when lubricatrs are used. Therefre, if lubricatrs are in use, they must nt run dry! The eternal questin: "Shuld lubricatrs be used r nt?" Answer: It always depends n the applicatin! In certain industries (e.g. fd industry) lubricatin is nt allwed at all. In ther industries with very big cylinders and strng frces, lubricatin can be really beneficial, especially fr the durability f the actuatrs. The lubricatrs in pneumatic systems use the Venturi principle. A pressure difference is generated by frcing the cmpressed air thrugh a jet. Behind the jet the pressure is lwer. This pressure difference sucks il frm the cntainer int the air stream where it is dispersed very finely. The same principle is used in a carburetr f a car running n petrl. Page 94

95 Chapter 10: Air Preparatin Units Lubricatr 1. Oil cntainer 2. Dsing unit 3. Bdy 4. Knb t activate sucking functin fr refill. Sme lubricatrs have a devise that enables il t be sucked in while the equipment is pressurized with the aid f a vacuum. At the bttm f the bdy, a tube has t be cnnected. The end is t be held int the il. Press the buttn (4) and the lubricatr is refilled with il. Air preparatin units pictures and ISO symbls Filter unit Pressure regulatr Lubricatr Page 95

96 Chapter 10: Air Preparatin Units Filter regulatr with pressure gauge FRL-unit (filter, regulatr, lubricatr and pressure gauge) Manually-actuated main switch-n valve, 3/2-way 3/2-way slenid valve with manual verride Sft starter valve Sft starter valve with electric actuatin Page 96

97 Chapter 10: Air Preparatin Units CAUTION! It is insufficient t have nly ne filter and ne pressure regulatr fr the entire system. Due t the vlatile cnsumptin f cmpressed air, the different pieces f equipment need individual air preparatin (pressure, smetimes als different air quality, filtratin / lubricatin). We recmmend t lcally prepare the cmpressed air fr the different pieces f yur equipment. This reduces wear-ut and increases the durability f machines and equipment. There are many prducts t chse frm: Further infrmatin can be fund in the categry FRL-units n ur website. Page 97

98 Chapter 11: Valves and Actuatrs with the NAMUR-interface Valves with NAMUR-interface t cntrl prcess valves 1. Pneumatic actuatin f prcess valves Prcess valves can be actuated manually, electrically, pneumatically and hydraulically. Often times pneumatic actuatrs are in use when it cmes t autmated prcess valves. They are mstly either linear actuatrs (pneumatic cylinders) r rtary actuatrs.. Whether it's a linear r rtary actuatr, the pneumatic autmatin f prcess valves is ppular. There are distinct advantages f pneumatic actuatrs in cmparisn t electric nes: High trque Lw maintenance Few spare parts High durability High reliability Useable in explsin hazardus envirnments Inexpensive As the field f applicatins and types f prcess valves is extremely wide, we will nt cver that. Instead we will fcus n the pneumatic actuatin and cntrl f rtary actuatrs with NAMURinterface. A pneumatically autmated prcess valve has three main parts: Page 98

99 Chapter 11: Valves and Actuatrs with the NAMUR-interface 1. Prcess valve Part f the pipe-line system, e.g. ball valve r butterfly valve. 2. Pneumatic rtary actuatr Opens and clses the prcess valve. 3. Pilt valve (with NAMUR-interface) Directinal cntrl valve fr cntrl f pneumatic rtary actuatrs. Further imprtant elements can be: Switch-bx t feed the psitin f the prcess valve back t a central cmmand, Manual verride clutch fr emergencies r Psitiner, replacing the switch-bx and mstly including the cntrl valve. 2. Pneumatic rtary actuatrs The design and dimensins f rtary actuatrs differ frm manufacturer t manufacturer. The tw mst ppular designs are either Sctch-Yke r Rack and Pinin actuatrs. We will intrduce yu t the Rack and Pinin actuatr with mre detail. The 2 pistn rds f the 2 pistns inside the actuatr are shaped like racks. Cmpressed air is driving them. The racks drive a pinin which is linked via a shaft t the prcess valve and pens r clses it. The selected size f the actuatr depends n the frce required t pen and clse the prcess valve. Usually the manufacturer indicates the maximum trque the actuatr ffers at a specific pressure. There are tw versins f linear actuatrs: Page 99

100 Chapter 11: Valves and Actuatrs with the NAMUR-interface Duble-acting actuatrs Single-acting actuatrs (with mechanic spring return) In duble acting actuatrs - depending n the directin required - cmpressed air flws t the utside r t the inside f the tw pistns. This can be easily cntrlled by using 5-way directinal cntrl valves (5/2-way fr fully pening and clsing the prcess valve, 5/3-way if intermediate psitins are required). In single-acting actuatrs, the reset t basic psitin is realized by using packs f mechanical springs. Tw packs f springs are psitined n the utside f the actuatr, pushing the pistns int the middle psitin. The area the springs are in is called the spring chamber. As sn as the actuatin side f the actuatr is exhausted, the springs push the pistns tgether, which turns the pinin and (depending n what is required) pens r clses the prcess valve. Page 100

101 Chapter 11: Valves and Actuatrs with the NAMUR-interface There are standards fr the cntact interfaces f a rtary actuatr, e.g.: Cntact interface t the cntrl valve VDI/VDE 3845 (NAMUR) Cntact interface t the prcess valve ISO 5211 DIN 3337 VDI/VDE 3845 (NAMUR) Interface n the actuatr that allws t flange directly a cntrl valve with NAMURinterface. ISO 5211 DIN 3337 Cnnectin t the prcess valve. Page 101

102 Chapter 11: Valves and Actuatrs with the NAMUR-interface 3. The NAMUR-interface NAMUR-valves are cntrl valves which ffer an assemblage interface accrding t the standard VDI/VDE NAMUR-valves are different frm ther in-line valves as they ffer tw prts n the flat side f the valve. In additin, there are hles fr fixing the valve nt the actuatr. The drawing belw shws a single slenid 5/2-way valve with an interface accrding t NAMUR. The dimensins f the 1/4 -interface, amng thers, are shwn as well. Type: MNH NAMUR-Interface VDI/VDE 3845 Besides the 1/4 -interface there is als ne fr larger actuatrs: G 1/4"- interface NAMUR valve descriptin: [NAMUR 1/4"] r NAMUR 1 G 1/2"- interface NAMUR valve descriptin: [NAMUR 1/2"] r NAMUR 2 Dimensins f the NAMUR interfaces n the actuatr T* D1 D2 M NAMUR 1/4" G 1/8 / G 1/4" M 5 NAMUR 1/2" G 3/8 / G 1/2" M 6 The hle M is typically used fr munting a setscrew nt the rtary cylinder, which fits int the blind bre f the valve and defines its perating directin. The hle R is usually used fr fastening screws. Page 102

103 Chapter 11: Valves and Actuatrs with the NAMUR-interface The picture displays a MNH , which is a 5/2-way single slenid NAMUR-valve. It is used t cntrl a duble-acting actuatr. Prts 2 and 4 are n the side f the valve. The prts are sealed twards the actuatr with O-rings. Prt 1 ( = supply) and prts 3 and 5 ( = exhausts) are n the flat side f the valve (shwn here n the tp). The picture displays an MNH , which is a 3/2-way single slenid NAMUR-valve. It is used t cntrl a single-acting actuatr. Prts 2 and ne prt 3 are n the side f the valve. The prts are sealed twards the actuatr with O-rings. Prt 1 ( = supply) and the ther prt 3 ( = exhaust) are n the flat side f the valve (shwn here n the tp). Page 103

104 Chapter 11: Valves and Actuatrs with the NAMUR-interface A nrmal 3/2-way inline valve has 3 prts. The 3-way NAMUR-valve n the pht hwever has 4, which yu can als see n its ISO symbl. WHY IS THAT? Single-acting actuatrs (the nes with springs) have 2 prts as well. One is cnnected t the actuatin side, the ther t the spring chamber. In rder t avid air frm the atmsphere (which might be wet, plluted r dirty) t enter the spring chamber, it shuld be ensured that (ptentially cleaner) prcess air enters it instead in rder t avid crrsin f the springs. That is why in prcess autmatin, we aim twards an air recirculatin int the spring chamber, als called a purge. When the actuatin side f the actuatr is exhausted (3/2-way valve n.c. in standard psitin), the actuatin chambers are gradually becming smaller and the spring chambers larger as the springs expand. The 3/2-way NAMUR-valve feeds part f the prcess air int the spring chambers befre it is used t expand the actuatin chambers. The excess air exhausts thrugh the external (secnd) prt 3. This functin is indicated in red in the ISO symbl. By feeding prcess air int the spring chambers, we want t reduce pllutin inside the actuatr due t dirt, dust, mist, misture etc. that might have been sucked int the spring chambers and thus avid crrsin f the springs. Page 104

105 Chapter 11: Valves and Actuatrs with the NAMUR-interface 4. HAFNER valves with NAMUR-interface HAFNER Pneumatik ffers a uniquely wide range f valves with NAMUR-interface, as well as a range f accessries. Slenid valves 3/2- (n.c. / n..), 5/2- and 5/3-way Pneumatically actuated valves 3/2-, 5/2- and 5/3-way Hand lever valves 3/2-, 5/2- and 5/3-way Everything mentined abve bth in NAMUR 1 and NAMUR 2 Numerus prducts made f stainless steel, fr cld and fr explsin-hazardus envirnments Flw-regulatr plates Quick-exhaust valves and purge-blcks Numerus safety valves (manually, pneumatically r electrically actuated) Plates and accessries HAFNER des nt nly ffer standard prducts but als ffers: NAMUR Flex 5/2-way valve with a kit t cnvert it int a 3/2-way valve with air recirculatin Stainless steel valves made frm (316L) Lw temperature valves -50 C t +50 C High temperature valves -20 C t +80 C BSP r NPT prted ATEX-certified prducts fr explsin-hazardus envirnment Specially selected materials brass-free prducts Prducts with air springs r cmbined springs Prducts with swapped prts Prducts with different types f manual verride Page 105

106 Chapter 11: Valves and Actuatrs with the NAMUR-interface Values f the standard Hafner 5/2-way NAMURvalve type MNH : - Orifice size : DN 7 mm - Flw: 1250 l/min - Operating pressure : 2-10 bar - Pwer cnsumptin: 3 W / 5 VA (in cmbinatin with standard cil MA 22) - Prts 1, 2, 3: G 1/4" - NAMUR 1: 1/4" MNH : same valve, but with a cmbined mechanical and pneumatic spring return. MNH MNH Standard sizes f HAFNER NAMUR-valves: Series 701 rifice: 7 mm flw: 1250 l/min prts: G 1/4" 1/4" NPT NAMUR 1, 1/4" Series 101 rifice: 10 mm flw: 2250 l/min prts: G 3/8" NAMUR 1, 1/4" maximized air-flw Series 121 rifice: 12 mm flw: 3000 l/min prts: G 1/2" 1/2" NPT NAMUR 2, 1/2" Cnfrming t standards, the flw measurement is shwn as nminal flw in [l/min]. Nminal flw: at p1= 6 bar, p = 1 bar, stream-value f the cmpressed air (l/min). Page 106

107 Chapter 11: Valves and Actuatrs with the NAMUR-interface Besides maximum flw f l/min in a cmpact design there are 10 mre cmpetitive advantages f the Hafner NAMUR-valves series PA fixing nut, which prtects the slenid system frm wetness and misture. 2. Cil MA 22 fully cvered with PA r Epxy (n request), 360 rtatable. Others (Ex-versins) available n request. 3. Brass peratr tube, including O-ring t prtect slenid system frm wetness frm the bttm. 4. Head made frm PA. 5. Brass manual verride fr turning; ther versins and materials (e.g. stainless steel) n request. 6. Spl made f stainless steel; ther inner parts are: brass, POM, NBR, FKM. 7. Fixing screws, stainless steel. 8. Bdy, andized aluminum. 9. End-cap made frm brass. 10. Unique sealing system, the HAFNER swimming O-Ring. Page 107

108 Chapter 11: Valves and Actuatrs with the NAMUR-interface 5. Selectin f Hafner NAMUR-Accessries MNH : HAFNER NAMUR-Flex valve HAFNER s MNH is a single slenid 5/2-way NAMUR -valve, electrically actuated with air spring return. It is used t cntrl dubleacting actuatrs (with the same functin as the MNH ). Adding the Flex-Plate type FP 701, the valve is cnverted int a 3/2- way NAMUR-valve with air recirculatin fr the spring chamber (purge). The MNH ffers a cmbined spring return. FP 701 MNH wrks like a 5/2-way valve MNH Flex plate wrks like a 3/2-way valve This valve is als available bth in stainless steel and NPT prted. Page 108

109 Chapter 11: Valves and Actuatrs with the NAMUR-interface DRN : Flw regulatr plates The Hafner flw regulatr plates ffer a very precise cntrl f the peningand clsing speed f actuatrs. Regulatin pssible with 3- way and 5-way valves. Additinally the DRN ffers the nly pssibility t regulate the frwardand backward-strke f single-acting actuatrs, which is cntrlled by a 3-way valve, independently and precisely. DRN 601 Tw different types f actuatin are available: 1. DRN _ 601: t be perated manually 2. DRN_ 611: t be perated with a screwdriver Plates are available with 1/4 and 1/2" NAMUR-interface. Assemblage between NAMUR pilt-valve and actuatr r with threaded plate type GPN-1/4 fr direct piping. DRN 611 DRN 3 fr single-acting actuatrs DRN 5 fr dubleacting actuatrs Page 109

110 Chapter 11: Valves and Actuatrs with the NAMUR-interface UB 701: NAMUR Air-recirculatin blck The air-recirculatin blck guarantees, that nly exhausting air frm the actuatin chamber is ging int the spring chamber. N ambient atmsphere is sucked-in. It is used in cmbinatin with single-acting actuatrs when they get cntrlled by remte installed 3/2-way valves e.g. frm a cntrl cabinet. The integrated nn-return valve makes sure, that n ambient atmsphere can enter the actuatr. Blck is designed fr actuatrs with 1/4 NAMURinterface. Prt 1 fr air-pressure supply G 1/4 threaded. 2 x G 1/4 exhaust prts. Further infrmatin abut ur NAMUR-valves and accessries can be fund in ur catalgue Cmpetence in Valve Autmatin. Page 110