초록 ▼

The invention provides a pilot valve apparatus for use in an automatic fluid control system for maintaining pressure downstream from a main control valve between two setpoints irrespective of flow changes through the main control valve. The pilot valve has a flexible pilot diaphragm which moves with

The invention provides a pilot valve apparatus for use in an automatic fluid control system for maintaining pressure downstream from a main control valve between two setpoints irrespective of flow changes through the main control valve. The pilot valve has a flexible pilot diaphragm which moves with a moveable pilot valve member to cooperate with a fixed pilot valve member to control fluid flow through the pilot valve apparatus. The pilot valve controls control pressure acting on the main control valve. An actuator apparatus connected to a body of the pilot valve apparatus has a moveable actuator partition which is exposed to a pressure differential signal reflecting flow through the main control valve. A resilient connector cooperates with the actuator partition and the pilot diaphragm to permit limited relative movement therebetween, and to transfer resilient force to the pilot diaphragm resulting from movement of the actuator partition. This transfer varies location of the moveable pilot valve member with respect to the fixed pilot valve member to vary flow through the pilot valve apparatus, so as to vary control pressure, which in turn controls the main control valve. An adjustable actuator stop can cooperate with the actuator partition to limit movement of the actuator partition. An actuator resilient member can cooperate with the actuator partition to apply a force selectively to the actuator partition to resist displacement thereof.

대표청구항 ▼

[ What is claimed is:] [32.] A method of controlling fluid flow through a main valve to maintain downstream pressure substantially between two pre-determined set-points, the method comprising the steps of:(a) detecting inlet pressure in fluid flow adjacent an inlet of the main valve and generating a

[ What is claimed is:] [32.] A method of controlling fluid flow through a main valve to maintain downstream pressure substantially between two pre-determined set-points, the method comprising the steps of:(a) detecting inlet pressure in fluid flow adjacent an inlet of the main valve and generating a control pressure signal proportional to said inlet pressure;(b) transmitting a first portion of the control pressure signal to act on a main valve member of the main valve to control position of the main valve member based on flow through the main valve;(c) transmitting a second portion of the control pressure signal to a pilot valve apparatus to control flow therethrough, the pilot valve apparatus having a flexible pilot diaphragm;(d) generating two pressure differential signals to reflect the fluid flow rate through the main valve;(e) transmitting the pressure differential signals to opposite sides of a moveable actuator partition of an actuator to deflect the actuator partition in response to said pressure differential signal;(f) transmitting downstream pressure to the pilot diaphragm; and(g) transmitting a resilient force to the pilot diaphragm arising from at least a portion of said deflection of the actuator partition so as to vary flow through the pilot valve, which in turn modifies the control pressure acting on the main valve member to re-position the main valve member to maintain downstream pressure substantially between the set-points.