Valve assembly having leak detection apparatus

In a valve assembly including first valve means operable to permit gas flow through a first port from an inlet to an outlet of said first valve means, and second valve means thereafter operable within a predetermined time to permit gas flow over a second port from an inlet to an outlet of said second valve means, a gas flow control means comprising a housing having first and second inner chambers, said first chamber having an inlet communicating with said outlet of said first valve means and an outlet, a control valve having an inlet communicating with said outlet of said first chamber and an outlet, and a valve member disposed to open and close a control port of said control valve which is interposed between said inlet and said outlet of said control valve, and valve actuator means operatively coupled to said valve member for normally maintaining said valve member in a flow-permitting position relative to said control port to permit gas flow through said first chamber from said outlet of said first valve means to said outlet of said control valve whenever said first valve means is operated, said second chamber having an inlet communicating with said outlet of said second valve means to permit gas flow into said second chamber whenever said second valve means is operated, to establish a pressure in said second chamber which operates on said valve actuator means to cause said valve actuator means to maintain said valve member in flow-permitting position relative to said control port, said valve actuator means being responsive to a pressure created within said first chamber in response to the flow of gas through said first chamber and in the absence of a pressure in said second chamber within said predetermined time to move said valve member toward a flow-preventing position relative to said control port, to thereby interrupt gas flow to said outlet of said control valve.

In a valve assembly, the combination comprising a gas valve comprising a first housing including a main body portion having a central passageway interconnecting an inlet and an outlet of said valve, said main body portion having first and second ports formed therein between said inlet and said outlet, a first valve member disposed to normally close said first port, and a second valve member disposed to normally close said second port, said first valve member being operable to open said first port to permit gas flow through said first port from said valve inlet to an inlet of said second port, and said second valve member thereafter being operable within a predetermined time to open said second port to permit gas flow from said first port to said valve outlet over said second port, and a gas flow control means including a second housing having a central cavity, a pressure diaphragm extending within said cavity, dividing said cavity into first and second chambers, said first chamber having an inlet communicating with said first port and an outlet, a control valve having an inlet communicating with said outlet of said first chamber and an outlet, and a third valve member operatively coupled to said diaphragm and movable therewith to open and close a control port which is interposed between said inlet and said outlet of said control valve, and bias means operatively coupled to said diaphragm for applying a force thereto for normally biasing said diaphragm to position said third valve member to a flow-permitting position relative to said control port to permit gas flow through said first chamber from said first port to said outlet of said control valve whenever said first valve is operated, said second chamber having an inlet communicating with said second port to permit gas flow into said second chamber whenever said second valve is operated to establish a pressure in said second chamber which operates on said diaphragm to maintain said third valve member in flow-permitting position relative to said control port, the gas flow through said first chamber creating a pressure which operates upon said diaphragm in the absence of a pressure in said second chamber within said predetermined time to offset the force of said bias means to move said third valve member to a flow-preventing position relative to said control port to thereby interrupt gas flow to said outlet of said control valve.

In a fuel ignition system including a pilot burner, a main burner apparatus, a first valve operable to permit gas flow from an inlet to an outlet of said first valve, and a second valve thereafter operable within a predetermined time to permit gas flow from an inlet to an outlet of said second valve which is connected to an inlet of said main burner apparatus, a valve leak detection apparatus comprising a housing having first and second inner chambers, said first chamber having an inlet connected to said outlet of said first valve and an outlet, and a control valve having an inlet communicating with said outlet of said first chamber and an outlet connected to an inlet of said pilot burner, said control valve having a valve member disposed to open and close a control port which is interposed between said inlet and said outlet of said control valve, and valve actuator means operatively coupled to said valve member for normally maintaining said valve member in a flow-permitting position relative to said control port to permit gas flow through said first chamber from said outlet of said first valve to said pilot burner and to establish a pressure in said first chamber, said second chamber having an inlet connected to an outlet of said second valve to permit gas flow into said second chamber whenever said second valve is operated to establish a pressure in said second chamber which operates on said valve actuator means to cause said valve actuator means to maintain said valve member in flow-permitting position relative to said control port, and the pressure in said first chamber operating on said valve actuator means in the absence of a pressure in said second chamber within said predetermined time to move said valve member to close said control port to thereby interrupt gas flow to said pilot burner.

In a fuel ignition system including a pilot burner and a main burner apparatus, a valve assembly comprising in combination a gas valve including a first housing having a main body portion with a central passageway interconnecting an inlet which is connected to a gas source and an outlet which is connected to said main gas burner apparatus, said main body portion having first and second ports formed therein between said inlet and said outlet of said gas valve, a first valve member disposed to normally close said first port, a second valve member disposed to normally close said second port, a gas flow control means including a second housing having a central cavity, a pressure diaphragm extending within said cavity dividing said cavity into first and second chambers, said first chamber having an inlet communicating with said first port and an outlet, a control valve having an inlet communicating with said outlet of said first chamber and an outlet connectable to an inlet of said pilot burner and a third valve member operatively connected to said diaphragm to open and close a control port which is interposed between said inlet and said outlet of said control valve, and bias means operatively coupled to said diaphragm for applying a force thereto for normally biasing said diaphragm to position said third valve member to a flow-permitting position relative to said control port to permit gas flow through said first chamber and over said control valve from said first port to said pilot burner whenever said first port is open, said second chamber having an inlet communicating with said second port to permit gas flow into said second chamber whenever said second port is open, said first valve member being operated in response to a request signal to open said first port to permit gas flow through said first chamber and said control valve to said pilot burner for ignition, and said second valve member being operated in response to the ignition of the gas supplied to said pilot burner to open said second port to supply gas to said main burner apparatus for ignition by said pilot flame and to said second chamber to establish a pressure in said second chamber which operates on said diaphragm to maintain said third valve member in flow-permitting position relative to said control port, the gas flow through said first chamber creating a pressure which operates upon said diaphragm in the absence of a pressure in said second chamber for a predetermined time to offset the force of said bias means to move said third valve member to a flow-preventing position relative to said control port to thereby interrupt gas flow to said pilot burner.