Wandfluh Pilot Operated Check Valve, Screw-in Cartridge Style

See Section 2.7, Data Pages 2.7-62E  Model RNX-PM33-x. This model is also still available in the smaller 22mm size, though it is not in the latest catalog. Design features are the same, parts are scaled down.

The design offers some desirable features that assure superior operating performance in the critical load holding area as well as providing long wearing reliable product so important in heavy duty mobile equipment machines.

1.  Note the poppet type spool is push type to seal and held in position by both the pilot spring and the actuator pressure; thus insuring that the tapered poppet/spool is fully seated and driving the poppet onto the seat.  This adds additional strength to the holding force, and aids in forming a tighter seat to assure virtual zero leak when holding a loaded cylinder.

2.  Note also that the pilot spool is fully guided (bearing) and the poppet seat cannot cock or the seat, or wobble when traveling.

3.  Note that there is a O ring groove cut in the pilot piston. This allows for an O ring seal on the pilot piston when the pilot piston can receive the signal for pilot shift function if pilot pressure is used from another separate function. For ordering this option, signify b adding the number C7 to the end of the model number.

4.  All steel metal parts, such as the one piece cartridge body, are of zinc plated steel, (stainless on special option) and are rated to 5500 psi continuous duty. Standard seals are of Buna N (Nitrile) Rubber, or Viton, ethylene propylene (EPR) seals on request.

5.  The model RNXPM33-x is rated to 350 bar working pressure, 160 liters/minute. The model RNXPM33-x is rated to 350 bar and 80 liters/Minute. 

Ed V. Askey