Pilot operated diaphragm valve

• US 4,135,696 A
• Filed: 11/01/1976
• Issued: 01/23/1979
• Est. Priority Date: 11/01/1976
• Status: Expired due to Term

• Current Assignee: Garden America Corporation
• Original Assignee: Richdel, Inc.
• Inventors: Saarem, Myrl J., Soukup, Dale F.
• Primary Examiner(s): Rosenthal, Arnold
• Application Number:
  US05/737,673
• Time in Patent Office: 813 Days
• Field of Search: 251/30, 251/42, 251/43, 251/46, 251/45
• US Class Current: 251/30.02
• CPC Class Codes: F16K 31/385 the fluid acting on a diaphragm
• CPC Class Codes: F16K 31/402 acting on a diaphragm

Abstract

A pilot type diaphragm valve assembly is provided which includes a solenoid-operated pilot valve which may be opened to remove fluid pressure from a chamber in the valve housing causing the main valve to open, and which may be closed to cause a buildup of hydraulic pressure in the valve housing causing the main valve to close. The solenoid-operated pilot valve includes an outlet which may be coupled to a reservoir at atmospheric pressure, or to any other suitable receptacle, to make the pressure differential across the diaphragm within the valve independent of pressure differentials in the fluid flow through the valve so as to obviate instability at low flow rates.

Claims

1. A valve assembly for controlling liquid flow, said valve assembly including:

a casing defining an inlet and an outlet, and also defining a valve chamber, an auxiliary chamber, and a conduit interconnecting the valve chamber and the auxiliary chamber, said auxiliary chamber having a discharge port for discharging liquid from said valve chamber and from said auxiliary chamber;

means defining a bleed port for introducing liquid into said valve chamber;

a valve actuator movable in said valve chamber between a first position in which the valve defines an open path between said inlet and said outlet, and a second position in which the valve closes said path;

a diaphragm supporting said valve actuator in said valve chamber and providing a seal for said valve chamber;

a solenoid operated valve positioned in said auxiliary chamber and including a plunger extending into said discharge port to permit the discharge from the valve chamber when the pilot valve is in an open position so that there is insufficient pressure exerted on the valve actuator to hold the valve actuator in its second position thereby normally to establish the valve actuator in its first position;

a valve seat positioned in said discharge port, and said plunger having a distal end positioned to seat against said valve seat when the pilot valve is closed, said pilot valve serving to block the flow of liquid through said discharge port when closed so as to cause a pressure build-up in said valve chamber causing said valve actuator to move to its second position; and

an outlet line coupled to said discharge port and to the inlet of a pump to discharge liquid from the discharge port to a point independent of said valve outlet so as to establish a material pressure differential across the diaphragm independent of pressure differentials in the liquid flow through the valve so as to obviate instability at low flow rates.