4WEH Series-Solenoid Operated Directional Valves Directional control valves

CHARACTERISTICS

• Valves used to control the start, stop and direction of a fluid flow.
• Electro-hydraulic operation (WEH), hydraulic operation(WH)
• For subplates mounting, porting pattern to DIN 24 340 form A, ISO 4401 and CETOP-RP 121 H
• Spring or pressure-centred, spring or hydraulic offset
• Wet-pin DC or AC solenoids, optional.
• Manual override, optional

HOW TO ORDER

FUNCTIONAL DESCRIPTION

• Valves of type WEH are directional spool valves with electrohydraulic operation.
• They control the start, stop and derection of a fluid flow.
• The directional valves basically consist of the main valve with housing (1),main control spool(2),one or two return springs (3.1)and (3.2)and the pilot valve(4) with one or two solenoids ”a”(5.1) and /or”b”(5.2).
• The main control spool(2) in the main valve is held in the neutral or in the initial position either by the springs or by means of pressure.
• In the initial position, the two spring chambers(6) and (8) are connected to the tank without pressure via the pilot valve(4). The pilot valve is supplied with pilot fluid via the pilot line(7). The pilot oil supply can be either intemal or extemal (extemal via port X). When the pilot valve is operated, e.g. solenoid “a”, the pilot spool(10)is shifted to the left and thus spring chamber (8) is pressureised with pilot pressure. Spring chamber (6) remains unpressurised.
• The pilot pressure acts on the left side of the main control spool (2) and pushes it against the spring(3.1). As aconsequence, the ports P to B and A to T are connected in the main valve.
  When the solenoid is de-energized, the pilot spool returns to its initial position(exception: detented spool ). The spring chamber (8) is unloaded to tank.
  The pilot oil is expelled from the spring chamber via the pilot valve into the Y channel.
  The pilot oil supply and drain are internal or extermal (extemal via port Y)
  An optional manual override(9) pemits pilot spool(10) to be operated without energizing the solenoid.