Vickers. Proportional Valves. EPV16 Series Valvistor Proportional Flow Controls

Transcription

1 Vickers Proportional Valves EPV6 Series Valvistor Proportional Flow Controls

2 Vickers, Incorporated, 998 All rights reserved

3 Features and Benefits The EPV (Electro Proportional Valve) series of poppet valves using the Valvistor poppet provides: High dynamic response on the main poppet valve to discrete pilot valve commands. Acts as a free flow check valve with good anti-cavitation characteristics when flow is reversed. The Valvistor poppet and its pilot stage are packaged into one industry standard compact screw-in cartridge valve. The valve has the benefit of flow force pressure compensation, the performance of which is application dependent. Refer to the pressure compensation curve. If pressure compensation is critical, we recommend the use of a separate hydrostat in line with the EPV valve. Application opportunities abound in the process control, paving, AWP, industrial truck, crane, retrieval systems,conveyor systems and agricultural machinery markets; as well as on any other equipment in the mobile vehicle and industrial machinery markets where precise control of velocity or position is desirable. The EPV6 is also available for industrial applications mounted in a body with a CETOP 5 (NFPA D05) interface. This option has proven to be successfully competitive in the plastic injection molding machine market. A major design feature of the EPV6 series valve is that a separate pilot flow supply is not required and all flow used for the pilot function is returned to the valve outlet. This eliminates the need for a separate hydraulic pilot supply circuit. In addition, the EPV series valves offer the following features and benefits. Features Very fast response Repeatability Low hysteresis Integral feedback Unequalled simplicity Electrical operation Optional nose-in, side-out or side-in, nose-out flow direction Free flow in the reverse direction Cost effective design Benefits Provides the operator with high dynamic acceleration/velocity/deceleration profiles for demanding performance requirements such as: Lift/lower position control Rotary actuator dynamic control Profile control Provides repeatable and accurate actuator velocity to a given operator command input. Typical hysteresis is less than 4% of rated current at 0 bar pressure drop. Accurate position control demonstrated on a new line of industrial presses. Internal hydraulic feedback provides effective, low cost, flow force pressure compensated proportional control of valve flow. Eliminates need for inner feedback loop and associated electronics. The valve accepts a PWM signal, or a direct current signal. Provides system design options and flexibility. Provides a check valve function with good anti-cavitation characteristics. Provides the multiple functions of pressure compensation, flow control and reverse free flow check valve.

4 Table of Contents Features and Benefits Model Code Control Application Data Operation Optional Features Side-in, nose-out operation Stand alone valve bodies Manual override Performance Curves Typical pressure compensation Typical metering performance Step response Installation Dimensions EPV6-A Nose-in, side-out EPV6-B Side-in, nose-out EPV6-A-**-S-5C-**D-(*)-*-2 CETOP 5 Interface EPV6-B-**-S-5C-**D-(*)-*-2 CETOP 5 Interface Body/Form Tools/Service Kits Modified C-6-3S body Standard form tooling for C-**-3S cavities Coil kits Seal kits Standard Cavity Dimensions Way Short Cavity

5 Model Code Electro Proportional Valve Nominal size 6 Size 6 3 Flow direction A Nose in, side out B Side in, nose out 4 Rated 0 bar P L/min (0.5 USgpm) L/min (6 USgpm) 0 00 L/min (26 USgpm) 6 60 L/min (42 USgpm) 5 Valve housing material (Omit for cartridge only) S Steel/iron A Aluminum 20 bar (3000 psi) maximum 6 Port sizes (Omit when ordering cartridge only) 0H SAE 0 Ports 2H SAE 2 Ports 4G BSPF G /2 Ports 6G 5C BSPF G 3/4 Ports CETOP5 (NFPA D05) interface (Requires steel/cast iron body) 7 Voltage rating 2D 2 VDC 24D 24 VDC 8 Manual override option M Pin type S Screw type Omit if not required 9 W Flying leads Q Dual SAE /4 Spade U DIN Y Metri Pack (Preferred Packard connector) F Weather Pack 0 Electrical connections Design number

6 Control The EPV (Electro Proportional Valve) can be driven by a 2 VDC, 24 VDC or PWM signal. Control of the EPV6 can be as simple as a rheostat for hand-eye coordination systems to the convenience of a power plug or with the sophistication of an amplifier card. Smooth performance has also been achieved through the use of joy stick controllers with and without amplifier cards. The preferred and recommended method of control of the EPV6 is with a PWM controller with the following characteristics: Nominal supply voltage: Minimum current for full function: Pulse frequency: Coil resistance: Threshold current: Ramp: Rheostat specifications: CAUTION These have a tendency to run hot if used in other than intermittent operations. 2 / 24 VDC.4 / 0.7 amp 00 + / 0 Hz 6.4 / 25.5 (68F) Adj. from mamp (2 VDC) Adj. from mamp (24 VDC) Adj. from mamp (2 VDC) Adj. from 300 to 700 mamp (24 VDC) Optional 2 VDC operation 0-2 2, watts 24 VDC operation 25-30,, watts Power plug options: EHH-AMP-702 (Indoor applications) EPAD-SA-A6-0 0 (These require 24 VDC power supply to power plug and 2 VDC coil on EPV6) Amplifier card: (Indoor applications) EEA-PAM-523 (Requires 24 VDC power supply and either 2 VDC or 24VDC coil on EPV6) Joy stick suppliers: OEM Controls, Inc, Shelton, CT (Outdoor applications) Ph: Fax: P-Q Controls, Inc., Bristol, CT Ph: Fax: Fluids roper fluid condition is essential for long and satisfactory life of hydraulic components and systems. Hydraulic fluid must have the correct balance of cleanliness, materials and additives for protection against wear of components, elevated viscosity and inclusion of air. Essential information on the correct methods for treating hydraulic fluid is included in Vickers publication 56, Vickers Guide to Systemic Contamination Control, available from your local Vickers distributor or by contacting Vickers, Incorporated. Recommendations on filtration and the selection of products to control fluid condition are included in 56. Recommended cleanliness levels using petroleum oil under common conditions is based on the highest fluid pressure levels in the system: Fluids other than petroleum, severe service cycles or temperature extremes are cause for adjustment of these cleanliness codes. See Vickers Publication 56 for exact details. System Pressure Level bar (psi) Product ( ) Proportional Valves 20+ (3000+) 7/5/2 5/3/

7 Application Data Ratings Flow range Rated pressure 0-60 lpm (0-42 USgpm) 280 bar (4000 psi) NFPA rated Operating ambient temperature C (-22 to +94 F) Typical hysteresis Less than 4% of rated current at 0 bar pressure drop Pulse Width Modulated (PWM) Leakage at P of 40 bar (2000 psi) and oil viscosity of 30cSt Oil viscosity range EPV6-A EPV6-B cst 50 cc/min maximum 0 cc/min maximum Fluids Electrical requirements Coil current for maximum flow Recommended PWM frequency Antiware hydraulic oils with Buna N seals (standard). Phosphate esters (non alkyl) with Viton seals are available by request. Viton is a registered trademark of E.I. DuPont.4 amps 2 VDC 0.7 amps 24 VDC Hz, application dependent, 00 Hz typical Coil 20C 2V V 25.0 Power rated current and 20C coil temperature Electrical connections Manual override Installation interface Weight (cartridge only) 2 volts 2.8 watts 24 volts 2.8 watts Refer to model code for options Refer to model code for options Modified C-6-3S kg (2.2 lbs.) WARNING: Application of these products beyond published performance specifications may cause valve malfunction which may result in personal injury and/or damage to the machine. 3

8 Operation Description The EPV (Electro Proportional Valve) is a series of poppet valves using a unique pilot operated technology controlled by either 2/24 VDC or a PWM signal packaged in an industry standard screw-in cartridge valve configuration. It provides flow force pressure compensated flow control for a broad range of velocity or position control requirements in both the mobile vehicle and industrial machinery markets. It can be applied in hydraulic systems either as a stand alone valve or in conjunction with other valves in a manifold or block. A characteristic feature of the EPV valve is the concept of using pilot flow to control the position of the main stage poppet valve. The main poppet amplifies a small flow through the pilot circuit comparable to a transistor. Thus the name Valvistor, derived from the combination of valve and transistor. As commanded by pilot flow, the unique closed loop internal position feedback system regulates inlet flow proportional to opening displacement. This provides servo-like precision position control of the main poppet without the need for an expensive LVDT and associated electronics. feedback flow passages for either the EPV6-A or the EPV6-B flow directions are provided for in these bodies, which do not have the third port as normally contained in the standard C-6-3S body. Installation dimensions for these modified bodies are shown in section Body/Form Tools/Service Kits. These modified bodies are recommended for all stand alone valve applications. When the standard C-6-3S stand alone bodies are used, the following guidelines apply: EPV6-A: Port 3 is to be plugged. EPV6-B: Port 3 is to be connected to Port in order to provide the required hydraulic feedback flow path. CAUTION A separate check valve is required down stream to isolate the EPV valve from load forces when the EPV is used to hold a load. The EPV construction and features open up a broad range of applications and uses for the valve with hydraulic cylinders and motors in the lift truck, forestry, agricultural equipment, paving, AWP, conveyor systems and process industries. The EPV6 series of screw-in cartridge valves are designed to fit into the 3-way short cavity. This is an industry accepted standard and tooling for either aluminum or steel bodies is readily available. The installation dimensions section of this catalog provides dimensional details for the undercut version of the C-6-3S cavity we recommend for the EPV6 series valves. Information is also included for form tooling for the machining of these cavities and dimensions for stand alone valve bodies. EPV6 series valves are available as either loose cartridge valves or assembled in either aluminum or steel stand alone valve bodies. Refer to model code when ordering loose valves or stand alone valve bodies. When ordered in a stand alone body, the Port 2 annulus is undercut to ensure maximum performance in extreme operating conditions at full rated flow. Internal ÇÇÇ ÇÇÇ ÇÇÇ

9 The EPV proportionally controlled two way valve is of the poppet type and is well suited for screw in cartridge design (see Figures and 2). The main poppet amplifies a small flow through the pilot circuit and is comparable to a transistor. As the transistor uses small currents to control larger currents, the hydraulic valve transistor or VALVISTOR uses the pilot flow to control the main stage flow with servo like response. Hydraulic position feedback is obtained by providing the poppet with a longitudinal slot (5) in its cylindrical surface. This slot, together with a metering edge inside the sleeve, forms a variable orifice between the inlet of the valve and the volume above the main poppet (3). When the valve is closed and the main poppet is sealed, the variable orifice area is also closed. As the main poppet opens, the variable orifice area increases. The slot is a part of one leg of a hydraulic bridge circuit and provides an internal position feedback. A pilot valve (4) is connected between the volume (3) and the valve outlet (2). Assume the pilot valve is closed and there is no pilot flow through the slot in the piston. The pressure above the main poppet, in volume (3) is equal to the pressure of the inlet () of the valve. This is due to a slight leakage in the variable orifice. Since the area of the poppet facing the volume (3) is larger than the area facing the inlet (), the poppet is held to the seat (6) by a force which is proportional to the pressure difference between inlet () and outlet (2). Because of the metering area of the slot, the variable orifice increases as the main poppet opens, and the flow through the slot increases. The movement of the main poppet stops when the flow through the slot is equal to the flow through the pilot valve. The main poppet is now in a steady state position. If the flow through the pilot valve decreases (by closing the pilot valve) the main poppet will move downward and close off the slot until a new balanced position has been obtained. Thus, by controlling the flow through the pilot valve, we can continuously control the position of the main poppet from a closed to a fully open position. In this manner, very simple servo control of the main poppet has been obtained. By opening the main poppet, with its much larger flow area, we can control the much larger main flow across the valve with a relatively small pilot flow. Notably, the pilot flow is added to the main flow in the outlet of the valve. Therefore, the valve will not use any flow for its control function and is energy efficient. If the outlet pressure is larger than the inlet pressure, and if the pilot is closed; the main poppet will act as a check valve and reverse flow will take place. 5 WARNING: Ensure screw override is in the neutral position prior to activating this valve OUTLET Opening the pilot valve (4) lowers the pressure in the upper volume (3). This moves the main poppet upwards and opens the slot, forming the variable orifice (See figure 2.). This causes a flow through the pilot circuit. Initially, the flow through the pilot valve equals the flow through the slot plus the flow resulting from the opening movement of the main poppet. 6 INLET Figure 2. EPV with pilot valve open. The main poppet will move upwards as long as the flow through the slot is less than the flow through the pilot valve. 5

10 Optional Features Side-in, nose-out operation An option to the standard valve configuration is for the direction of the primary flow to be reversed through the valve for side-in, nose-out operation. This is accomplished by a change to the poppet valve and screw-in valve body (see Figure 3). This requires the use of an additional construction hole in the manifold or block in which the screw-in cartridge is installed; or, alternately, external plumbing to connect the pilot flow feedback loop to the valve outlet. Stand alone 2 ported valve bodies are available as the recommended alternative to the 3 ported C-6-3S bodies. The 2 ported bodies incorporate both the undercut in Port 2 annulus for full rated flow operation and the internal hydraulic feedback required for the EPV6-B. If the 3 ported stand alone body is used, external plumbing is required to connect Port 3 to Port. This is necessary to provide the internal hydraulic feedback loop the the Valvistor main stage poppet. Also, problems may be encountered in obtaining full rated flow through the valve. WARNING: When using the Screw Type override, care must be taken to return the override back to its neutral position before activating the valve. Failure to take this precaution may result in personal injury or damage to the machine. M Pin type manual override option S Screw type manual override option Stand alone valve bodies The EPV valves are available either as loose cartridge valves or installed in industry standard, stand alone 3-way short valve bodies. These bodies are standard production items and available in either aluminum for up to 20 bar (3000 psi) operation or in steel for up to 280 bar (4000 psi). Refer to Installation Dimensions section of this bulletin. Manual override Manual override is available in two different configurations, either push pin type or screw pin type. The push pin type is used when system pressure does not exceed 20 bar (3000 psi). The screw pin type can be used at any system pressure Schematic of side-in nose-out EPV6-B. Figure 3. Sectional view of side-in nose-out EPV6-B valve. For EPV6-B (flow 2 to ), Port 3 must be connected to Port externally to the cartridge, either by passages in the cavity block or external plumbing. When purchased with undercut body, this connection is included in the body and Port 3 is not machined. A separate external port connection is not required for EPV6-A (flow to 2). 2

11 Performance Curves psid * FLOW % I H G bar PRESSURE DIFFERENTIAL *Flow interims of % for each poppet size F E D C B A Command Current 2V A 600 ma B 700 ma C 800 ma D 900 ma E 000 ma F 00 ma G 200 ma H 300 ma I 400 ma 24V 300 ma 350 ma 400 ma 450 ma 500 ma 550 ma 600 ma 650 ma 700 ma * FLOW % UPPER TOLERANCE OF FLOW NOMINAL FLOW (LOWER TOLERANCE) E D C B A Pressure Differential A B C D E 0 bar 20 bar 50 bar 00 bar 200 bar 45 psi 290 psi 725 psi 450 psi 2900 psi (24V) (2V) COMMAND CURRENT, ma *Flow interims of % for each poppet size Delay 90% Reach time 0 On stroke valve response time 90% COMMAND SIGNAL Delay FLOW RESPONSE TIME 00% 0 00% 90% Reach time 0% Off stroke valve response time Pressure l/min (30 USgpm) Pressure drop P 20 bar (300 psi) 00 bar (500 psi) On Stroke Delay Reach 90% 24 ms 35 ms 7 ms Off Stroke Delay Reach 90% 5 ms 5 ms 7 ms 7

12 Installation Dimensions EPV6-A Nose-in, side-out mm (inch) Third angle projection 2 27,3 (.07) Screw type actuator (shown) 3 mm hex socket 43,5 (.7) Electrical connection DIN (Coil can be rotated about core tube axis to desired orientation) 29,0 (5.07) 24,7 (4.90) 85,3 (7.29) 67,9 (2.67) 8,0 (7.2) 2 Port.32-2 thd. EPV6-A (With manual actuator) EPV6-A (No manual actuator) 38, Hex (.50) Port (.00) EPV6-B Side-in, nose-out ,3 (.07) Screw type actuator (shown) 3 mm hex socket 43,5 (.7) Electrical connection DIN (Coil can be rotated about core tube axis to desired orientation) Required external connection with standard C 6 3S cavity 29,0 (5.07) 24,7 (4.90) 85,3 (7.29) 67,9 (2.67) 8,0 (7.2) 3 Port 2 Port.32-2 thd. EPV6-B (With manual actuator) EPV6-B (No manual actuator) 38, Hex (.50) Port (.00) (.25)

13 EPV6-A-**-S-5C-**D-(*)-*-2 CETOP 5 Interface mm (inch) Third angle projection 276,0 (0.9) Required for removal 29,7 (8.65) 99,5 (3.92) UNC x socket head cap screw (Bolt Kit ) M6 x 60 socket head cap screw (Bolt Kit ) 7,6 (2.82) 69,5 (2.74) 60,0 (2.38) 5,0 (2.0) ISO-440-AC-05-4-A (NFPA D05) mounting surface 22,8 (.89),7 (.46) P A B Ta Tb 6.96 / 6.85 thru 4 holes EPV6-B-**-S-5C-**D-(*)-*-2 CETOP 5 Interface 5,0 (2.0) 7,6 (2.82) 69,5 (2.74) 60,0 (2.38) UNC x socket head cap screw (Bolt Kit ) M6 x 60 socket head cap screw (Bolt Kit ) 276,0 (0.9) Required for removal 29,7 (8.65) 99,5 (3.92) ISO-440-AC-05-4-A (NFPA D05) mounting surface 22,8 (.89),7 (.46) P A B Tb Ta 6.96 / 6.85 thru 4 holes 9

14 Body/Form Tools/Service Kits Modified C-6-3S body, standard aluminum fatigue-rated bodies mm (inch) Modified body for use with EPV6-A Modified body for use with EPV6-B 30,2 (.9) 60,4 (2.38) 38, (.50) Dia. thru 2 mtg. holes 2 79,2 (3.2) 00,8 (3.97) 2,6 (.85) 2.7 (.50) 2 plcs. 76,2 (3.00) Code Port size Housing number Aluminum Steel EPV6 A EPV6 B EPV6 A EPV6 B 4G /2 BSPP G 3/4 BSPP H SAE H SAE T SAE T SAE C CETOP5 (NFPA D05) interface (Requires steel housing) For applications over 20 bar (3000 psi), dimensionally interchangeable steel housings are available upon request. Standard form tooling for C-**-3S cavities Note: The undercut can be machined with a standard #4 T slot milling cutter modified to turn down its shank from 3/4 inch to 5/8 inch or its neck diameter of.594 inch. Coil Kits Seal Kits Roughing Tools Cavity Size Aluminum Steel/Cast Iron Shank Dia. mm (inches) C-6-3S RT-6-3S-A-8044 RT-6-3S-S ,4 (.000) Finishing Tools Cavity Tool designation Shank Dia. For machining Size mm (inches) C-6-3S FT-6-3S-AS ,40 (.000) Aluminum or steel Coil Kits Type 2V 24V W Flying leads Q Dual SAE / 4 Spade U DIN Y Metri Pack F Weather Pack Cartridge Seal Kit CETOP5 Seal Kit Seals for all options included in kit, therefore some models will have extra seals that will not be needed

15 Standard Cavity Dimensions 3-Way Short Cavity mm (inch) The EPV6 cartridge in this catalog is designed to fit into the cavity dimensioned on this page Cavity bores can be machined accurately in aluminum or steel. The necessary UN threads may be machined using standard small tools, possibly already in your machine shop or from a local tool supplier. For in depth advice on the machining of cavities, consult your Vickers sales specialist. Either you, our customer, or Vickers can design and manufacture customized manifolds or housings dedicated to individual applications. We call the resulting valve packages Modular Circuit Designs (MCDs). Cartridges selected for your application can be accommodated in one or more MCDs, according to your requirements. 46,02 (.82).32-2 UN 2B 3,30/3,68 (0.30/0.45) 6,67 (0.656) 6, Dia ,45 (,750) 35,58 (.40) 3,34 (.234) B 28,62 (.27).2 (45) R ( ) (0.03) 7,46 (0.687) 20,62 (0.82) 37,3 (.469) A 5,87 (0.625).575 (0.062) R.2 (45) 5,88 (0.625) Dia ,58 (2.88).575 R (0.062) 9,05 (0.750) Dia. 25,45 (.002) These diameters.0508 mm (.002 inch) B unless otherwise specified. 36,5 (.437) Dia. Recommended undercut.0254 mm (.00 inch) A unless otherwise specified.

16 Eaton Hydraulics 55 Highway 5 Eden Prairie, MN Telephone: Fax: New Lane, Havant Hampshire PO9 2NB England Telephone: (44) Fax: (44) Form No Copyright Eaton Corporation, 0000 All rights reserved. Printed in U.S.A 558 Rev. 7/98 Printed in U.S.A.