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US 4,986,468 AGranted
Test circuit for system monitoring apparatus
AssigneeA.O. Smith Corporation
InventorJohn J. Deisinger
Life of this patent
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AssigneeA.O. Smith Corporation
InventorJohn J. Deisinger
Estimating the term…
A gas fired burner includes a pilot gas valve and a burner gas valve sequentially operated to light the burner. A monitor includes individual monitoring of the status of the valves and the burner as well as other components and systems associated with the burner and includes separate lamps for each components. A test circuit monitors the sequential ignition cycle and includes a timing circuit having a timing period somewhat longer than the selected ignition period. An indicator lamp is connected to the timing unit. A sensing device is connected to the pilot gas valve and to the burner gas valve and each establishes an output in response to activation of pilot gas valve and burner valve. The pilot valve signal turns on the timing unit and the burner valve signal turns off the timing unit such that the indicator lamp is actuated only if ignition of the burner is not established within said selected ignition period. The signals are applied to a common input of a comparator, the output of which is connected to the timing unit.
A monitoring apparatus including status monitoring of a gas-fired operating system including a gas fired burner having an electrically actuated pilot unit and a main burner unit ignited from said pilot unit, comprising a pilot sensor unit sensing turn-on of said pilot unit, a burner sensor unit sensing turn-on of the main burner unit, a first comparator unit having a reference input and having a second input connected to said pilot sensor and to said burner sensor unit and having an output, a timing unit connected to the output of the comparator, said pilot sensor unit being operable to establish an activation of said comparator and said burner sensor unit being operable to hold said comparator deactivated whereby said comparator establishes an output only in the absence of turn-on of the main burner and said timing unit times out only if the main burner does not turn-on within the period of said timing unit.
A gas fired burner apparatus having a pilot gas valve and a main burner gas valve and wherein said pilot gas valve opens to establish a pilot flame at said main burner and said main burner gas valve opens to establish a main flame in the presence of said pilot flame, said main flame being established within a selection ignition period in response to activation of said gas valves, the improvement including a test unit for monitoring said ignition period, comprising a timing unit having a timing period corresponding to said selection ignition period, an ignition cycle indicator connected to said timing unit, first sensing means connected to said pilot gas valve and establishing a first output in response to activation of said pilot gas valve to actuate said timing unit, and a second sensing means connected to said burner gas valve and establishing a second output in response to activation of said burner gas valve to deactivate said timing unit whereby said indicator is actuated if ignition of the burner is not established within said selected ignition period.
A gas fired hot water heater having a storage tank for storage of water, comprising a burner having a gas line, a burner valve in said gas line and having an electrical operator for opening and closing the valve, a pilot unit having a pilot gas line, a pilot valve in said pilot gas line having an electrical operator for opening and closing the pilot valve, a first sensor unit having an input coupled to said electrical operator of said burner valve and having an input an output, a second sensor unit having coupled to said electrical operator of said pilot valve and having an output, a comparator unit connected to said outputs of said sensor units and activated by said output of said sensor unit of said pilot valve and deactivated by said output of said sensor unit of said burner valve, a resettable timing unit connected to said comparator unit and initiating a timing cycle in response to activation of said comparator unit and being resettable in response to deactivation of said comparator unit, said timing unit having a timing period equal to a selected maximum ignition period, whereby said timing unit establishes a fault signal if said main burner valve does not operate to supply gas to said burner within said selected ignition period, and an indicating lamp connected to said timing unit.
Dependencies are inferred from the claim text.