Valves of type FE are pilot-operated 2-way proportional throttle valves for block installation for the continuous control of flows.
Technical set-up
The valve consists of four main assemblies:
Cover (1) with connection surface for pilot oil connections
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Main valve (2) with orifice spool (3)
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Pilot control valve (4) with proportional solenoid (5)
‐General function:
Command value-dependent position control of the orifice spool (3) and thus defined opening of the orifice (8)
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The flow depends on the Δp across the orifice (8) and the position of the orifice spool (3)
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Actual value recording of the orifice spool (3) position by the position transducer (7); command/actual value comparison in the electronics (6); variations are prepared and forwarded as control output for correction of the orifice spool (3) position to the proportional solenoid (5) to the pilot control valve (4)
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Area ratio of area (15) to area (12) = 1 : 1
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Flow direction A → B; connect X to A or connect externally
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With external pilot oil supply, the pressure at X must be ≥ the pressure in A in order for the valve to work
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Pilot oil bypass via the nozzle (16) increases the vibration absorption
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When the enable is disconnected, the orifice spool (3) in the valve socket will move against stop (17) (closed position) and block the flow from A → B
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Orifice spool position at command value 0 V or 4 mA already regulated, whereas the orifice (8) is still located in the positive overlap and blocks A → B
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Zero flow over the orifice spool (3) and the pilot control valve (4) at command value 0 V or 4 mA as well as inactive enable see technical data
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Open orifice spool function:
Flow A → B and A connected to X
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The proportional solenoid (5) moves the pilot spool (4.1) against the spring (13) and opens the connection from control chamber (12) to Y; pressure reduction in the control chamber (12) and movement of orifice spool (3) in opening direction by the pressure in A on the area (15)
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Close orifice spool function:
Flow A → B and A connected to X
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Flow reduction in the proportional solenoid (5); the spring (13) moves the pilot spool (4.1) against the proportional solenoid and opens the connection from X to the control chamber (12); pressure build-up in the control chamber (12); pressure on the orifice spool area in the control chamber (12) plus spring force (10) move the orifice spool (3) in closing direction
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Flow control function:
Can be used in connection with a pressure compensator for the load-compensated control of a flow
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Supply voltage failure:
The electronics de-energize the solenoid in case of supply voltage failure or cable break in the position transducer (7)
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The pressure applied to control port X plus the spring force (10) move the spool into closed position where it blocks the flow A → B
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Notice:
Failure of the supply voltage will lead to an abrupt standstill of the control axis. The acceleration forces occurring in this connection may cause machine damage!