Set-up
The pilot-operated proportional directional valve type 2WFCE basically consists of:
- Cover (1)
- Main stage (2)
- Pilot control valve with proportional solenoid (3)
- Integrated electronics with position transducer and analog interface (4) or external control electronics as module amplifier
The electronics (integrated or external) compare the specified command value to the position actual value of the control spool of the main stage (2). In case of control deviations, the solenoid of the pilot control valve (3) is activated. In this way, the control spool is adjusted. Depending on the control deviation, the control chamber of the main stage (2) is either pressurized with pilot oil (the main stage closes) or unloaded (the main stage opens). Stroke and orifice cross-section are controlled proportionally to the command value until the control deviation is remedied.
For proper function, the following has to be observed:
- Direction of flow A → B (X connected to A)
- Direction of flow B → A (X connected to B)
- Port Y depressurized to the tank
Failure of supply voltage
If the minimum supply voltage fails or is fallen below, the enable is disconnected (only interfaces B1 and G1) and in case of a cable break of the solenoid conductor, the electronics will de-energize the solenoid of the pilot control valve (3). The control spool of the main stage (2) moves securely to its seat using the pressure available at port X and the force of the main stage spring and blocks the flow between A and B.
Flow control function
In connection with a pressure compensator, the pilot-operated proportional directional valve can be used for the pressure-compensated control of a flow.