Patent ID: 7740224
Filing Date: 2010-06-22
Classification: F15B,G01N

Abstract:
1. A valve, comprising: a valve housing; at least first, second and third fluid ports extending through said valve housing; a main piston guided for movement in said valve housing; a pilot control designed as a seat valve with a pilot piston actuated by an electromagnet to move to an open position where fluid flows from one of said first and second fluid ports, actuated by said main piston, via a cross-sectional constriction orifice in said main piston and via said pilot piston to said third fluid port actuated by said pilot piston, said main piston traveling to a respective control position as a result of an accompanying pressure drop to actuate said first and second fluid ports relative to amounts of fluid, piston lift of said main piston with said pilot piston in said open position being proportional to current supplied to said electromagnet, a free end of said pilot piston having a closing and sealing part interacting with a seat part on a part of said valve housing; a compression spring between said main piston and said pilot piston and received in a main piston recess in said main piston, said cross-sectional constriction orifice discharging into said main piston recess; and a contact piece on a free end of said compression spring adjacent said pilot piston, said contact piece connected to a free end of said pilot piston by a contact ball.