Valves of type 3WRCE are pilot-operated, 3-stage directional high-response cartridge valves. They control the quantity and direction of a flow and are mainly used in control loops.
Set-up
The valves consist of the following assemblies:
- 1-stage pilot control valve (1)
- with two solenoids as electro-mechanical converters and a control spool that is connected to the integrated pilot electronics (6.2) via electrical feedback
- Second stage (2) for flow control
- Inductive position transducer (3) the core (4) of which is attached to the main control spool (5) of the second stage
- Integrated electronics (OBE) (6.1).
Function
The integrated electronics (OBE) compares command and actual values and the solenoids of the pilot control valve (1) are actuated with a proportional current according to the control deviation.
The pilot control valve (1) takes a proportionally controlled position and controls the flow in and out of the control chambers A (7) and B (8) that actuate the main control spool (5) through the closed valve control loop up to 0 control deviation.
This means that the stroke of the main control spool (5) is regulated proportionally to the command value. It must be noted that the flow also depends on the valve pressure drop.
Valve features
The opening point of 0% (symbol V) is set at the factory.
Due to the internal setting of the pilot control valve, the pilot pressure is connected to control chamber B (8) in case of a power failure, i.e. the main stage is opened from A to T or the connection P to A is closed.
The spring behind the main control spool moves the control spool only into position so that P to A is closed
if no pressure is applied (e.g. prior to installation, before the pressures are reapplied after tool change).
The integrated control electronics (OBE) feature an offset setting to compensate pilot trimming.
Notice:
Version “3WRCE” is not recommended for new applications.
If version “3WRCE” is used, ports A and P have to be exchanged. Upon request.
