Patent ID: 6057771
Filing Date: 2000-05-02
Classification: G01M,Y10T

Abstract:
In a fluid delivery apparatus comprising: a flow line for delivery of a fluid through said flow line, the flow line comprising an upstream, section downstream, and an section intermediate section between said upstream and downstream sections: a closable upstream valve and a closable downstream valve, said valves being interconnected in series in the flow line through said intermediate section, a method of detecting a failure of a said valve to close fully wherein said method comprises the steps of:(a) putting both said valves in a fully-closed setting;(b) detecting the pressure of said fluid in the intermediate section; and,(c) initiating an alarm condition, but only if the said pressure fails to change in a predetermined way,wherein step (a) comprises putting the downstream valve in said fully-closed setting before putting the upstream valve in said fully-closed setting,whereby the alarm condition is responsive to failure of at least one of the said valves to close fully.