Gas combustion control apparatus
First Claim
1. Apparatus for controlling the combustion of a fuel in an appliance comprising:
- means for receiving the exhaust gases of the appliance,means for maintaining the exhaust gases at a substantially constant temperature between the steam point and the dew point of the gases,humidity sensor means for monitoring the relative humidity of the substantially constant temperature exhaust gases and for producing an output signal upon the relative humidity deviating from a predetermined level, andcontrol means for using said output signal to control the combustion of fuel in the appliance to maintain the humidity at said predetermined level.
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Accused Products
Abstract
Apparatus for controlling the combustion of natural gas in a natural gas fired appliance is described. Exhaust gases are sampled and maintained at a predetermined constant temperature between the dew point and the steam point. The relative humity of the constant temperature gas is monitored by a hygrometer. Relative humidity deviations from a predetermined value result in output signals from the hygrometer to a control circuit. The control circuit is connected to regulators in the air intake or chimney of the appliance which regulate air intake to keep the relative humidity substantially constant and hence control combustion of the gas. In another embodiment the relative humidity of the exhaust gases and the combustion air intake are monitored by separate hygrometers which are linked to each other so that a change in the relative humidity of a gas affecting one hygrometer will compensate the other hygrometer and control combustion as before. The latter arrangement is useful when the relative humidity of the combustion intake air is very high as occurs in hot, humid summer weather.
14 Citations
21 Claims
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1. Apparatus for controlling the combustion of a fuel in an appliance comprising:
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means for receiving the exhaust gases of the appliance, means for maintaining the exhaust gases at a substantially constant temperature between the steam point and the dew point of the gases, humidity sensor means for monitoring the relative humidity of the substantially constant temperature exhaust gases and for producing an output signal upon the relative humidity deviating from a predetermined level, and control means for using said output signal to control the combustion of fuel in the appliance to maintain the humidity at said predetermined level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of controlling the combustion of a fuel in an appliance comprising the steps of
sampling the combustion exhaust gases from the appliance maintaining the temperature of the exhaust gases at a substantially constant value between the steam point and the dew point, monitoring the relative humidity of said substantially constant temperature gas, providing an output signal upon the monitored relative humidity deviating from a predetermined value, and using said output signal to control the combustion of fuel to return the humidity of said exhaust gases to the predetermined level.
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20. Apparatus for controlling the combustion of a heating appliance having gaseous combustion products comprising a passage to receive a sample of the exhaust gas of the appliance, heat exchange means associated with said passage to maintain said sample at a predetermined constant temperature between the dew point and the steam point of said gas, humidity sensing means in said passage downstream of said heat exchange means responsive to variations in the humidity of said gas to provide a control signal upon deviation of said humidity from a predetermined value, said control signal being operable upon said appliance to adjust the combustion thereof to maintain said humidity at said predetermined level.
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21. Apparatus for determining variations in the combustion products of a heating applicance intake air comprising a first humidity sensor adapted to receive combustion exhaust gases, a second humidity sensor adapted to receive intake air, the first and second humidity sensors being separated from contact with the intake air and the exhaust gases respectively, linkage means connected between the first and second sensors to compare changes in the humidity detected by said first and second sensors, said apparatus means producing an output signal upon a change in humidity detected by said first sensor only.
Specification