초록 ▼

A gas-fired construction heater which meets the applicable ANSI Standard and operates to supply heated air separately from products of combustion. The products of combustion are permitted to contain no more than a specified percent of carbon monoxide when uncontrolled heater operating conditions are

A gas-fired construction heater which meets the applicable ANSI Standard and operates to supply heated air separately from products of combustion. The products of combustion are permitted to contain no more than a specified percent of carbon monoxide when uncontrolled heater operating conditions are within predetermined ranges. The uncontrolled operating conditions include variations in input rate and supply voltage. A combustion chamber produces the products of combustion and has primary and secondary combustion zones. A heat exchanger receives the products of combustion and transfers heat therefrom to fresh air to be heated. The chamber and the heat exchanger define a tertiary combustion zone. Inlets supply a separate natural combustion draft to each of the primary and tertiary combustion zones. The inlets include a first and a third fixed-area inlet for respectively supplying the separate natural drafts to the primary and tertiary combustion zones. An additional fixed-area inlet supplies forced draft and natural draft to the secondary combustion zone. The fixed-area of each of these inlets is selected so that the specified percent is not exceeded during operation of the heater when the uncontrolled variation of either the input rate or the supply voltage is within its respective predetermined range. When the uncontrolled variations are outside of the respective predetermined ranges, the heater is turned off.

대표청구항 ▼

In a forced-air, gas-fired hot air construction furnace having: a burner for supplying the gas, a combustion chamber having an inlet wall and being adapted to contain the gas and products of combusting the gas, a plenum for receiving forced draft combustion air and directing the forced draft combust

In a forced-air, gas-fired hot air construction furnace having: a burner for supplying the gas, a combustion chamber having an inlet wall and being adapted to contain the gas and products of combusting the gas, a plenum for receiving forced draft combustion air and directing the forced draft combustion air toward said combustion chamber, a closed duct having an exhaust inlet for receiving the combustion products and an exhaust outlet for discharging the combustion products, means for guiding air to be heated over said closed duct, means for supplying forced air to said guiding means and to said plenum, means for discharging the heated air from said guiding means, means for sensing the pressure of the forced air in said supplying means, and means for sensing an operating temperature in said guiding means; the improvement in said furnace comprising: means for rendering said furnace capable of operating without manual adjustment of air flow to said combustion chamber, such operation of said furnace being in compliance with a selected standard which does not permit such manual adjustment but which limits the maximum percent of a given chemical compound which is permitted to exit said exhaust outlet when the rate of supplying the gas to said burner varies within a defined range and when voltage supplied to said supplying means varies within a preset range and causes variation of the pressure at which the forced air is supplied, such variation being relative to a low limit, said rendering means comprising: combustion air inlet means provided in said inlet wall of said combustion chamber and having separate fixed inlet areas for admitting draft combustion air to said combustion chamber at first, second and third locations that are progressively closer and closer to said exhaust inlet to said closed duct; baffle means mounted close to said wall of said combustion chamber for selectively blocking the forced draft in said plenum so that only natural draft air is admitted to said first and third locations and both forced and natural draft air are admitted to said second location; said pressure sensing means being adjusted for responding to pressure of the forced air below the low limit, said low limit pressure being the lowest pressure at which said maximum percent of the given chemical compound does not appear in the combustion products exiting said exhaust outlet; said temperature sensing means being adjusted for responding to the operating temperature exceeding a selected maximum temperature, said maximum temperature being selected to permit the pressure of the gas supplied to said burner to be at a maximum required by said selected standard when said forced air pressure is at the lowest required by said selected standard; and means responsive separately to said pressure sensing means responding to pressure below said low limit or to said temperature sensing means responding to an operating temperature above said maximum temperature for interrupting the operation of said burner. A method of rendering a forced-air, gas-fired hot air construction heater capable of operating in conformance with an emissions standard, said heater having a burner for supplying the gas, a combustion chamber having an inlet wall and being adapted to contain the gas and products of combusting the gas in first, second and tertiary combustion zones, a plenum for receiving forced draft combustion air and supplying forced draft combustion air to said combustion chamber, a closed duct having an inlet for receiving the combustion products and an exhaust outlet for discharging the combustion products, means for guiding air to be heated over said closed duct, means for supplying forced draft air to said guiding means and to said plenum, manually adjustable means for admitting primary combustion forced air from said plenum into said first combustion zone, means for discharging the heated air from said guiding means, means for sensing the pressure of the forced air in said guiding means, means for sensing the operating temperature in said closed duct as said duct receives the combustion products, said method rendering said heater capable of operating without manual adjustment of said means for admitting the primary combustion forced air, such operation of said heater being in compliance with the emissions standard, the emissions standard not permitting such manual adjustment, the emissions standard limiting the maximum percent of a given chemical compound which is permitted to exit said exhaust outlet when the rate of supplying the gas to said burner varies within a predetermined rate range and when said forced air supplying means supplies the forced air at varying pressure within a predetermined pressure range, said method comprising: blocking the forced draft air flowing in said plenum toward said admitting means so that only natural draft air flows toward said admitting means and into said first combustion zone of said combustion chamber; fixing the area of said admitting means at a selected non-variable area; providing in said wall of said combustion chamber secondary combustion air inlet means having separate second fixed inlet areas for admitting secondary combustion air to said second zone of said combustion chamber; partially blocking the forced draft air flowing in said plenum toward said secondary combustion air inlet means to permit both forced draft air and natural draft air to enter said separate second fixed inlet areas; providing in said inlet wall or said closed duct third fixed tertiary combustion air inlet means for admitting natural draft tertiary combustion air to said third combustion zone of said combustion chamber; adjusting said pressure sensing means for interrupting operation of said burner when the pressure of the forced draft air decreases below a specified pressure, said specified pressure being the lowest forced draft air pressure at which said maximum percent of the given chemical compound does not appear in the combustion products exiting said exhaust outlet; and said adjusting temperature sensing means for interrupting operation of said burner when the operating temperature in said guiding means exceeds a selected maximum temperature, said maximum temperature being selected to permit the pressure of the gas supplied to said burner to be at the maximum end of said predetermined rate range defined by said selected standard.