Patent ID: 6935362
Filing Date: 2005-08-30
Classification: G05D,Y10T

Abstract:
1. A pilot valve for use in controlling a pressure reducing valve of a water supply system, said valve comprising: biasing means to control a gate for controlling water flow through a control chamber having an outlet connectable so that water pressure at the outlet is substantially equal to the outlet pressure of the pressure reducing valve being controlled; a second chamber being isolated from fluid communication with said control chamber and with the pressure reducing valve being controlled is sealed by a second chamber diaphragm into which control gas pressure is applicable for also controlling the operation of the gate, whereby, in use, an increase in control gas pressure acts to reduce water flow through the gate; the control gas pressure is different from the outlet pressure of the pressure reducing valve being controlled; and wherein the side of the diaphragm against which the control pressure is not applied, is in fluid communication with the control chamber.