Solenoid actuated valve with adjustable flow control

A solenoid valve assembly comprising:

• a valve housing having a valve inlet, a valve outlet, and a valve seat disposed therebetween;
• a valve member movable between open and closed positions with respect to said valve seat for respectively permitting and preventing fluid flow from said valve inlet to said valve outlet;
• a control chamber within said housing and adapted to receive pressurized fluid;
• a pressure-operated diaphragm coupled with said valve member and operable to move said valve member between said open and closed positions, said diaphragm having a generally annular flexible portion surrounding said valve member and disposed on opposite sides thereof in pressure communication with said valve inlet and said control chamber when said valve member is in the closed position, said valve member being disposed on opposite sides thereof in pressure communication with said valve outlet and said control chamber when said valve member is in the closed position;
• passageway means formed in said diaphragm flexible portion for admitting fluid from said valve inlet to said control chamber;
• a solenoid unit for controlling the pressure of fluid within said control chamber, said solenoid unit in one condition permitting the pressure within said control chamber to substantially equal the pressure at said valve inlet whereby the control chamber pressure acts on the diaphragm to hold said valve member in the closed position, and in another condition opening a bleed passage to relieve pressure within said control chamber sufficiently to permit pressure at the valve inlet to move said diaphragm to displace said valve member to the open position;
• and
• a flow control piston within said control chamber, said flow control piston having a generally cylindrical shape to define an annular leading edge presented toward said valve member, said valve member displacing toward said leading edge upon movement toward the open position and cooperating therewith in the open position to subdivide said control chamber into an outer annular zone in pressure communication with said diaphragm flexible portion and an inner zone in pressure communication with said valve member, said valve member cooperating with said leading edge to meter fluid flow from said outer zone to said inner zone, so that a substantially minimum pressure differential is maintained across said diaphragm flexible portion when said valve member is in the open position, said inner zone being in flow communication with the bleed passage when said solenoid unit is in said another condition opening the bleed passage.

A solenoid unit for use in a solenoid actuated valve, said solenoid unit comprising:

• a solenoid housing having a solenoid winding and a movable solenoid plunger mounted therein, said solenoid housing including an open nose end;
• a ported retainer mounted within said nose end and defining at least one fluid inflow port and a fluid outflow port separated by a valve seat, said solenoid plunger being movable between first and second positions for opening and closing said valve seat to respectively permit and prevent fluid flow from said inflow port to said outflow port;
• and
• a solenoid filter mounted at said nose end in a position over said inflow port to filter fluid entering said inflow port, said nose end of said solenoid housing and said solenoid filter including snap-fit means for removably retaining said filter over said at least on inflow port.