Wasser-hydraulisches Proportionalventil

摘要

A water hydraulic proportional control valve comprising: a valve body having a supply port, a control port and a return port; a spool axially movably disposed in the valve body for changing a direction of the working fluid and a flow rate of the working fluid; a direct driving mechanism which directly converts electric signals into a driving force for moving the spool, the valve opening of the control valve is controlled by means of a proportional control of the amount of a displacement of the spool from a neutral position thereof toward one direction or another according to an input signal supplied to the direct driving mechanism; spool side chambers provided on both sides of the spool; and drain channels formed in communication to each of the spool side chambers; wherein a water is used as the working fluid, and a flow passages is provided for introducing a pressurized fluid into said spool side chambers, whereby water filling the chamber is constantly replaced by a fresh water thereby preventing generation of microorganisms and decay of the water.