Patent ID: 8020585

Claim:
A duplex valve assembly comprising: a first valve assembly including an inlet opening for receiving fluid, an outlet opening for delivery of fluid, a fluid flow passageway defined between the inlet opening and the outlet opening, and means for controlling the flow of fluid through the fluid flow passageway; means for indicating whether said first valve assembly is in a closed position or an open position; a second valve assembly including an inlet opening for receiving fluid, an outlet opening for delivery of fluid, a fluid flow passageway defined between the inlet opening and the outlet opening, and means for controlling the flow of fluid through the fluid flow passageway; means for indicating whether said second valve assembly is in a closed position or an open position; an intermediate fluid flow passageway defined between the outlet opening of the first valve assembly and the inlet opening of the second valve assembly, the intermediate fluid flow passageway positioned for the delivery of the fluid from the first valve assembly to the second valve assembly; a pressure change detector within the intermediate fluid flow passageway, said pressure change detector at least partially positioned within the intermediate fluid flow passageway to detect fluid leakage at either the first valve assembly or the second valve assembly; and a control system for receiving signals from said indicating means and said pressure change detector, said control system configured to indicate fluid leakage when said pressure change detector detects a change of pressure within the intermediate fluid flow passageway and said indicating means indicate that the valve assemblies are maintained in a closed position, wherein, in the event of a fluid leakage, said control system is configured to determine which of the valve assemblies has failed based entirely upon the change in pressure detected by the pressure change detector.