Piston accumulator stations in the hydropower industry

Transcription

1 Piston accumulator stations in the hydropower industry 1 2 Shut-off valves Provision of power for emergency shut-down of ball valves or ball check valves Turbines Provision of power for emergency shut-down of control equipment for all turbine types (e.g. control device for the Francis turbine)

2 CONTENTS Page 1. GENERAL 2 2. ACCUMULATOR STATIONS 3 3. PISTON ACCUMULATORS 4 4. SAFETY AND SHUT-OFF BLOCK NITROGEN BOTTLE CHARGING AND TESTING BLOCK F+P GAS-SIDE SAFETY ELEMENTS FRAMES FURTHER ACCESSORIES GENERAL Fluid power in hydro-electric energy Nowadays, hydro-electric power stations make a significant contribution to the supply of sustainable energy. For HYDAC, one of the leading companies in fluid power, hydraulics, process technology and electronics, this is yet another area where it proves its expertise, helping to make optimum use of the power of water. Hydraulic systems, like no other drive technology, provide a high degree of operating safety and power density, compact design, fatigue strength, minimum maintenance and in conjunction with electronics excellent control and monitorability. Ideally suited, therefore, to hydropower. This document has been designed for hydraulic accumulator applications in hydropower and provides HYDAC accumulator technology and engineering from a single source. We ensure that shut-off valves and turbines are supplied with power sufficiently and at the right times. Our specialists are happy to help. 2

3 2.1 TECHNICAL SPECIFICATION Operating pressure 210 bar Operating fluid zmineral oil HLP to DIN 51524, Part 2 zhlp 22 HLP 68 (observe viscosity in operating temperature range) Oil operating temperature -10 C C Ambient temperature -10 C C Coating of parts/components Primer + topcoat to HYDAC standard Coating of steel construction Sand blasting + primer + topcoat Piping (on gas side) Type: Walform Material: galvanised (optionally stainless steel) Size: DN 26 Acceptance European Pressure Equipment Directive (PED) (others on request) 2.2 MODEL CODE Series SS = accumulator station (e.g. SS210 = accumulator station with a p max. of 210 bar) SS210 K 1 x 500 / 12 x 75 (U) Piston accumulator station 2. ACCUMULATOR STATIONS HYDAC supplies completely piped, operationally ready accumulator stations, pipe fittings and safety devices either as an individual accumulator unit or back-up version with nitrogen bottles for enlarging the usable volume. The modular structure of the systems makes it possible for individual customer specifications to be incorporated into the project planning. HYDAC can calculate the required accumulator volume using the accumulator simulation program, taking the customer s own operating data into account. Please read the relevant operating manuals for the individual HYDAC components: zpiston accumulator (3.301.BA) GSV/GMP z (3.504.BA) zcharging and testing unit (3.501.BA) zsafety and shut-off block (3.551.BA) Type code letter K = piston accumulator B = bladder accumulator N = nitrogen bottles Number of accumulators Nominal volume [l] of the accumulators Number of nitrogen bottles Nominal volume [l] of nitrogen bottles Certification code (U) = European Pressure Equipment Directive (PED) 3

4 Gas valve end cap safety device Cover piston sealing system cylinder 3. PISTON ACCUMULATORS 3.1 DESIGN HYDAC piston accumulators consist of: za cylinder with very finely machined internal surface; zcovers on the gas side and the oil side (sealed with O-rings); zthe floating steel or aluminium piston which can easily be accelerated due to its low weight; za sealing system adapted to the particular application. The piston floats on two guide rings which prevent metal-to-metal contact between the piston and the accumulator wall. external seal end cap safety device Fluid port Design of piston accumulator 3.2 PISTON Piston type 3 Piston design type Type 3 Application zlow-friction design zsimple-to-fit seals zslow movements without stick-slip effect Max. piston velocity 0.8 m/s Filtration NAS 1638 class 6 ISO 4406 class 17/15/ DIMENSIONS L ±3 [mm] Volume [l] Ø D1 [mm] CONNECTIONS Dimensions Ø D1 [mm] Fluid side 1 1/2" 2" 2" 2" Gas side M28x1.5 M28x1.5 M28x1.5 M28x1.5 4

5 3.5 PISTON POSITION MEASUREMENT SYSTEM Cable tension measurement system Using the cable tension measurement system, the position of the piston can be determined by means of a cable which is fixed to the piston base. The cable is attached to a roller which is tensioned by a spring. During the piston movement, this roller alters the electrical resistance via an attached rotary potentiometer. The resistance is converted to an electrical signal by a measurement transducer. A display unit can be added to the system. This allows the position of the piston to be displayed, up to four positions to be tapped for wiring system parts and the electrical signal to be transmitted to a PLC, for example. Components: zmeasurement transducer: ma zdigital display unit (optional): -- HDA 5500, 2 switch points, AC -- HDA 5500, 2 switch points, DC -- HDA 5500, 4 switch points, AC -- HDA 5500, 4 switch points, DC Limits of application: zmax. piston acceleration: g zmax. piston velocity: 0.5 m/s zaccumulator installation: vertical, gas side up zlimits for piston accumulators: see following table Cable tension measurement system Cable tension measurement system possible Volume [l] Piston diameter [mm]

6 3.5.2 Magnetic flapper indication The magnetic flapper indication visualises the position of a piston on the basis of red/ white flaps which are visible externally. An anti-magnetic tube uses a cable fastened to the piston on the gas side with a magnet located at its end to move the magnetically folding red/white flaps. The change in colour in the display makes it possible to read the piston position. Additional components can be added optionally (e.g. components to control system parts). Components: The components described below are available as options and can be combined to suit the particular application and customer specifications. Please contact us and we will support you in selecting the system that is right for you. ztransducer: The transducer is attached to the outside of the upright tube, opposite the indicator rail. Various models are available, depending on the particular piston stroke. These are described in the following table: Magnetic flapper indication Technical data HLT 2150 Reed chain type W Function The HLT is used up to a piston stroke of 3765 mm. A ferro-magnetic conductor is tensioned and supplied with a current pulse (magnetostrictive measuring element wave guide) inside a tubular cable protection. From the current pulse, a radial magnetic field arises around the conductor. The reed chain is used for piston strokes of 3766 mm and above. The magnet actuates the reed switches in the transducer as it passes, which causes the resistance value to change. The resulting change in voltage is converted to a standardised 4-20 ma signal by an internal converter. The magnet fastened to the piston generates a longitudinal magnetic field in relation to the wire. If the two magnetic fields meet at the measurement point, a torsion pulse is triggered that spreads out from the measurement point with constant ultrasonic speed, moving along the wire in both directions. The ultrasonic sound signal is recorded via a sensing element inside of the sensor head and converted into an electrical output signal. The measured delay between sending out the current pulse until the torsion pulse arrives is converted into a 4-20 ma signal by the measurement electronics. Housing Stainless steel ( / Stainless steel ( / ) ) Supply voltage V DC V DC Electrical connection Current consumption without output Male connector M12x1 Cable 2x0.75 mm² (analogue: 4-pin, digital: 5-pin) 100 ma - Signal output ma ma Resolution Analogue: 12 bit, 0.1 mm 10 mm Operating -40 C C -20 C C temperature Sampling rate 2 ms - (internal) Cable - PVC, grey, length 5m Protection class IP 67 IP 68 6

7 zswitches: Three different magnetic switch versions are available: latching, N/C contact and N/O contact. Each one has a reed switch that switches when the magnet is present. The following overview describes the technical data, including the mode of operation: Technical data Mode of operation Latching BN310-RZ When the magnet passes, the contact is closed, remains closed and is only opened when the magnet returns. N/C contact BN310-01Z The contact is open when the magnet is present. Material of housing Plastic, glass-fibre-reinforced thermoplastic Material of cable HD03VV-F Weight 0.65 kg 0.75 kg 0.65 kg N/O contact BN310-10Z The contact is closed when the magnet is present. Electrical Cable 2x0.75 mm², 1 m long connection Service life, Min switching cycles mechanical Service life, switching cycles electrical Shock resistance 30 g / 11 ms Oscillation Hz, amplitude 1 mm resistance Bounce time ms Actuation speed Max. 18 m/s Restart accuracy +/ mm (T = constant) Ambient -25 C C temperature Protection class IP 67 to IEC/EN Switching speed Max. 18 m/s - - Switching time, m/s m/s closing Switching time, Max. 0.5 m/s Max. 0.5 m/s - opening Switching frequency < 300 Hz Flash-over voltage > 600 V AC (50 Hz) Switching voltage Max. 250 V AC/DC Switching current Max. 3 A Switching capacity Max. 120 W Limits of application: zmax. piston velocity: zaccumulator installation: 0.5 m/s vertical, gas side up 7

8 3.5.3 Piston position switches Piston position switches detect the position of a piston inside the piston accumulator through the wall of the cylindrical jacket. The piston position switch can be retrofitted with a clamp, with no further modification to the piston accumulator required. This makes fitting possible without disrupting operation. A clamp mount in the form of a clamp-on solution is provided for this purpose. The measurement principle is based on the ultrasonic pulse echo method. An electrical pulse is used to generate ultrasonic sound that is reflected on the rear wall of the cylinder and then evaluated. A rear wall echo that has been received is then signalised. The piston position switch detects the transition from oil to piston, at which point the signal is switched off. This is the case if the piston is in the sound path or has passed it. Furthermore, two piston position switches can be connected to each other. This makes it possible for the piston to move between two specified positions. 8 Piston position display Components: Device type Number of sensors per piston accumulator* Sensor design Measurement principle Measurement repetition rate Mounting to cylinder, coupling Accuracy Piston accumulator dimensions Fluids Viscosity of the medium Supply voltage Switching output Serial interface Connections Sensor cable length Switching point display * Multiple sensors possible on request BF1 standard design BF3 design for highly viscous media Piston position switch: ultrasonic position switch for pistons in piston accumulators and cylinders with no fittings 1 for single operating mode 2 for synchronous operating mode Compact sensor unit consisting of sensor element and evaluation electronics znon-contact ultrasonic pulse echo method zno sensor contact with fluid znormally no structural changes required to the cylinder, as measurements are taken through the wall from outside Max. 155 Hz Mounting in desired position with mounting clamp and mounting plate with M30 thread Coupling to cylinder with couplant Static ± 1 mm, measured from centre of sensor zexternal diameter: mm zinternal diameter: mm zmineral oil (HL, HLP) zhfa (HFB) zhfc zhfd zwater up to 100 cst up to 500 cst z18 to 30 V DC, max. 80 ma, ripple 10 % zundervoltage detection zreverse polarity protection zovervoltage detection znpn or PNP znpn or PNP zmax. switching current: zmax. switching current: 60 ma (external fuse 200 ma (external fuse provided) with maximum provided) switching current of zmax. switching voltage: 30 V DC positive operation zmax. switching capacity: voltage 1.8 W 1-wire interface for configuration and synchronisation (with programming adapter and PC) zsensor connector M12 zcable 4-pin without shield - brown: positive operation voltage 18 to 30 V DC - blue: negative operation voltage (GND) - black: switching output - white: synchronisation, serial programming for configuration 2 (or 5) metres with right-angle plug LED integrated into right-angle plug (green, yellow)

9 BF1 standard design BF3 design for highly viscous media Temperature range zaccumulator temperature: -20 C C (observe viscosity) zambient temperature: -20 C C zstorage temperature: -40 C C Protection class IP 67, oil resistant Housing zaluminium, anodised zh x Ø: 50 x 50 mm zthread M30 x 1.5 zearthed to GND Weight Approx. 170 g Approx. 250 g Individual parts None, only complete module Maintenance If sensor is repositioned, new couplant required Regulatory zprotection class: IEC529 (DIN 40050) information zemc active: EN 50081; EN zemc passive: EN 50082; IEC , -3, -4, -5, -6 Scope of delivery Sensor(s), mounting clamp(s), couplant, connection cable, operating manual (scope in accordance with quotation) Restrictions: None 9

10 4. SAFETY AND SHUT-OFF BLOCK 4.1 GENERAL The HYDAC safety and shut-off block SAF is a hydraulic accessory that is used to shut off and discharge hydraulic accumulators. The HYDAC safety valve (DB12) is used in the SAF series. It is a direct-acting pressure relief valve in poppet valve construction with excellent opening and closing characteristics. This version of the DB12 complies with the requirements of the European Pressure Equipment Directive (PED). 4.2 DESIGN AND CONNECTIONS The safety and shut-off block SAF is structured as follows: e.g.: SAF with additional equipment L or LPI Pressure relief valve DB12 M1 port (optionally with pressure gauge) ISO G 1/4 for SAF10 ISO G 1/2 for SAF20, SAF32 Shut-off valve Release spindle M2 port (e.g. for p 0-guard) ISO G 1/4 - for all sizes These devices are combined in the compact HYDAC safety and shut-off block. The following devices are also available: Solenoid-operated unloading valve (optional for version SAF E ) Needle valve Additional port designations: P Pump port T Tank port Circuit diagram SAF 4.3 SAF DESIGN Internal diameter piston accumulator [mm] Recommended SAF block Design Threaded connection Supplementary equipment Set pressure range (at PR) DN 10 DN 20 DN 32 Manual ISO 228 (BSP) L = lockable main shut-off valve (locking device) LPI = model L with additional position monitoring (inductive proximity switch) 210 bar 10

11 5. NITROGEN BOTTLE To increase the gas volume in the hydraulic accumulator, nitrogen bottles are used in back-up form. The advantage of doing this is that smaller accumulators can be used for the same gas volume and the costs of the entire volume package can be reduced. 5.1 DIMENSIONS Nitrogen bottle Volume Connections to ISO 228 (Type AA) Height ± 25 mm Weight [l] Drain side Connection side [mm] [kg] 50 D G 3/4 D G 3/ D G 3/4 G G 1 1/ Minimess connection Design of nitrogen bottle 6. CHARGING AND TESTING BLOCK The HYDAC charging and testing block F+P is used to charge and test back-up-type hydraulic accumulator stations. It has connections for the charging and testing unit FPU-1 and the pressure gauge. HYDAC supplies the following safety devices to secure against excess pressure and/or excess temperature increases: ztemperature fuse (see section 7.1) zbursting disc (see section 7.2) zgas safety valve (see section 7.3) These can be screwed into the F+P. In addition, it allows the back-up nitrogen bottles to be shut off from the hydraulic accumulator. Charging and testing block 6.1 RECOMMENDED F+P Description Max. operating pressure Weight Suitable for piston accumulator internal diameter [mm] [bar] [kg] F+P F+P Circuit diagram F+P Connection for charging and testing unit FPU-1* connection for gas safety valve Charging and testing block Nitrogen bottles Hydraulic accumulator 6.2 OPTIONS Optionally HYDAC can provide the possibility of attaching the connection for the charging and testing device to the frame at operator height. This comprises: zshut-off valve zpressure gauge zgas charging valve zminimess connection z1 vacant connection (e.g. for pressure switch) Safety and shut-off block Circuit diagram accumulator station with F+P 11

12 7. GAS-SIDE SAFETY ELEMENTS As established in the national regulations of numerous countries, it is recommended or mandatory that hydraulic accumulators be protected from excessive pressures. Design of GMP 6 Housing Discharge opening Threaded connection ISO G 1/4 7.1 TEMPERATURE FUSE Function HYDAC offers a temperature fuse of the type GMP 6 that is approved according to the European Pressure Equipment Direction (PED). It consists of a stainless steel housing that contains a fusing element that melts when the trigger temperature is reached and thus depressurises the accumulator. Temperature fuses are devices with a safety function and are used to release the gas pressure by discharging the nitrogen completely when an increase in temperature reaches unacceptable levels (e.g. in the case of fire) Technical data Permitted operating pressure bar Temperature range -40 C C Melting temperature Between +160 C and +170 C Recommended temperature fuse Acceptance GMP6-10-CE1637 Europ. Pressure Equipment Directive (PED) with CE marking, delivery with declaration of conformity and operating manual Discharge opening Screw-in thread 1/4" NPT or ISO G 1/4 7.2 BURSTING DISC Function If the pressure exceeds the permitted level, the bursting disc is destroyed. This permanently opens the port and reduces the gas pressure by discharging the nitrogen completely. Bursting discs are designed for different burst pressures and are supplied with a certificate of conformity. Bursting discs are made either entirely from stainless steel or from an alloy based on stainless steel and nickel. Design of bursting disc 12 Design of gas safety valve 7.3 GAS SAFETY VALVE Function The gas safety valve provides protection by reducing the pressure in a controlled way if pressure exceeds the permitted level unexpectedly. It consists of a housing which contains a compression spring for setting the cracking pressure. The spring is pre-set on the pressure side and lead-sealed by the authorised representative. It is also supplied with a certificate of conformity and operating approval Technical data Dimensioning zeuropean Pressure Equipment Directive (PED) zen ISO zen zothers on request Module category ziv in accordance with European Pressure Equipment Directive (PED) zmodule B + D (EC type approval) zmodule G (EC individual approval) on request Nominal size 6 mm Connection ISO 228 G 1/2 A Material zstainless steel zclosing element with flexible seat seal Medium Nitrogen (N2) Operating pressure range bar Temperature range -20 C C Weight 1.1 kg Length 206 mm Diameter 35 mm

13 8. FRAMES 8.1 FOR PISTON ACCUMULATORS Piston accumulators with Ø D1 Accumulator volume Height Width Length Weight of frame [mm] [l] [mm] [mm] [mm] [kg] Width Frame SK (example) Length Height FOR NITROGEN BOTTLES Width Frame SN (50 l) Length Height Volume N 2 Max. Height Width Length Weight bottle number of N 2 bottles N 2 bottle Frame Total [l] [l] [mm] [mm] [mm] [kg] [kg] [kg] Height Width Frame SN (75 l) Length 13

14 Release valve Design of FPU-1 Spindle Check valve Pressure gauge 9. FURTHER ACCESSORIES 9.1 CHARGING AND TESTING UNIT FPU-1 The HYDAC charging and testing unit FPU-1 is used to charge accumulators with nitrogen or to check or to change the existing pre-charge pressure in accumulators. For this purpose the charging and testing unit is screwed onto the gas valve of the hydraulic accumulator and connected to a nitrogen bottle via a flexible charging hose with a pressure reducer. Handling, inspection intervals and other operating-related information are given in the operating manual Design The HYDAC charging and testing unit for piston accumulators consists of: zvalve body zspindle zcheck valve zrelease valve zpressure gauge The standard scope of delivery also includes: zcharging hose (2.4 or 4 m) zadapter A3 The adapter A3 is included in the scope of delivery as standard, but it is not needed in connection with the piston accumulator. Adapter G Pressure reducer Charging and testing unit FPU-1 G1 Charging hose Adapter A Hydraulic accumulator Nitrogen bottle Fluid port Diagram of charging and testing procedure for bladder accumulator with FPU Dimensions with adapter for HYDAC hydraulic accumulator 14 Dimensions

15 9.1.3 Charging hoses Charging hoses are designed for the particular maximum permitted operating pressure marked on them and 10,000 charging processes. HYDAC charging hoses comply with the EC Machinery Directive and with DIN EN 982 and DIN EN 853 to 857. Charging hose F Charging hose FM Type Connection Length [m] F to DIN 477, Part FM FW to DIN 477, Part 5 up to April 2002 to DIN 477, Part 5 up to April Setting range up to 200 bar up to 300 bar 2.5 up to 300 bar Charging hose FW Nitrogen bottle 9.2 CONDENSATE DRAIN SET The condensate drain set consists of a needle valve and a suitable condensate draining hose. It is used to drain any condensate from the nitrogen bottle, in a controlled way. Condensate drain set Description Length [m] Condensate drain G 3/4 Minimess M16x1.5 - Condensate drain set Draining hose Needle valve Condensate drain set 15

16 Cooling Systems Electronics Accessories Compact Hydraulics Filter Systems Process Technology Fluid Filters Accumulators Global Presence. Local Expertise. HYDAC Headquarters HYDAC Companies HYDAC Sales and Service Partners HYDAC TECHNOLOGY GMBH Industriegebiet Sulzbach/Saar Germany Phone Fax: Internet: