Abstract: A heat exchanger and process having multiple fluidized beds for heat exchange between two gas streams of different temperatures. The apparatus and process provides a compact high efficiency warm air furnace especially adapted for energy conservation for the heating of modern highly insulated residential buildings by gas fired furnaces of relatively low rated gas input.

Abstract: An energy conserving device for preventing loss of heat energy from a heater to a chimney by means of a fluid gas heat trap to choke off either chimney draft and/or heated convectional air currents lost to the chimney when the heater is OFF but allowing combustion gasses to vent freely to the chimney when such gasses are generated. The deivce also acts as a diverter for either up or down drafts from the chimney to direct them away from the heater. In another form when the device is used with a forced air type furnace, the device in addition provides heat interchange between room air and the hot gasses in the trap. This then heated air is drawn into the circulating system of the furnace adding to its temperature while lowering the temperature of the vented combustion gasses, to lessen the heat loss up the chimney.

Abstract: A control circuit for a fuel supply and ignition control system controls the operation of pilot and main valves of the system and of a motor which controls the positioning of a vent stack damper plate to normally close the vent stack and to open the vent stack at the start of each ignition cycle. At the start of each ignition cycle, a start relay is operated to energize the pilot valve and a spark generator for a trial for ignition interval defined by the excursion time of the damper plate as it is driven to the open position. When the pilot fuel is ignited, a flame sensing circuit operates a flame relay which completes a holding path for the pilot valve and when the damper plate reaches the fully open position, limit switches connect the main valve to the holding path and deenergize the drive motor and the start relay.

Abstract: A flue damper is rotated 360.degree. in a predetermined direction in 90.degree. increments to be selectively opened and closed in 90.degree. increments. The incremental rotation is accomplished by a motor driven timing mechanism with power to the motor being controlled by the timing mechanism and a solid state switching means selectively energizing and deenergizing the motor.

Abstract: A draft control arrangement for use with a gas-fired heating apparatus. The flow of waste gas through a draft hood of the apparatus is throttled by bimetal element means which responds to temperature change for reducing or enlarging the throttle area. Control means is provided for causing the rate of throttle area change during a certain phase of operation to vary from the rate of throttle area change during other phases of operation.

Abstract: A thermally actuated control system for the chimney flue or vent damper of a hot air furnace employs a fluid reservoir supported in the vent between the damper and the furnace so as to experience the furnace temperature, containing fluid that has a liquid state when the furnace is not in operation and a gaseous state at the higher temperature resulting when the furnace goes into operation. A spring biased piston movable within the reservoir is connected to the damper shaft by a barrel cam supported exteriorly of the vent, which converts the linear motion of the actuator into rotation of the damper shaft. The change in temperature when the furnace goes on or off produces a resultant change in the volume of the fluid within the reservoir, moving the linear actuator between its two positions and rotating the cam and the damper so that the damper is in an open position when the furnace is on and a closed position when the furnace is off.

Abstract: For use in a ventilation flue or the like, a damper positioning mechanism comprising a yieldable means biasing said damper toward a first position, motive means for opposing the bias of said yieldable means to drive said damper to a second position and thermally responsive means modulating the return of said damper from said second position to said first position, said thermally responsive means being strong in relation to said yieldable means. In one embodiment the thermally responsive means resists closure of said damper until exposed to a sufficiently low temperature. In another embodiment the thermally responsive means resists opening of said damper until exposed to a sufficiently high temperature.

Abstract: A thermally controlled damper construction for a gas fired combustion apparatus such as a furnace or the like is described. A damper is pivotally mounted within the stack or flue of the combustion apparatus for pivotal movement from a closed position, wherein the damper is located at an acute angle with respect to the axis of the stack, to a full open position. One edge of the damper is recessed to provide a vent opening between the damper and the stack to permit the venting of gases generated by operation of the pilot light during periods when the furnace is not operating. The damper is pivotally moved between its closed and open positions by a bi-metallic thermally responsive element which is located upstream of the damper and which is connected to the damper by means of a linkage. The linkage includes means for permitting the unrestrained rotational movement of the bi-metallic element after the damper is in its position thereby preventing stressing of the thermally responsive element at high temperatures.

Abstract: Combustion apparatus having a vent with a damper actuated by an element comprised of a material having a shape memory effect. The element is heated and cooled above and below the deformation temperature for causing the element to deform between its different shapes for changing the position of the damper within the vent. Control means is provided in one embodiment for heating the shape memory element so that it deforms for moving the damper closed during a shutdown mode of the combustion apparatus, and in another embodiment the shape memory element is heated so that it deforms to a shape for holding the damper open during the heating mode of the apparatus.

Abstract: In an embodiment thereof, the closure device comprises a leaf-type, planar, closure element pivotally coupled to a supporting shaft. The shaft is fixed in traverse of a fluid conduit, and the closure element is rotatable therewithin for opening and closing the conduit to fluid flow. Shape-memory alloy components are engaged with the element, and a bearing surface, to cause the element to move from an opened or closed position to the other thereof, or to some intermediate positioning for metered or damping fluid flow, in response to prescribed temperatures.

Abstract: An automatic damper control comprising: damper means for use in a flue or the like; diaphragm means adapted to expand and contract in response to pressure variations in the flue; and sensor means for sensing the pressure in the flue. The sensor means is connected to the diaphragm means and comprises means for generating a plurality of beams of light. The sensor means further comprises collimating means adapted to collimate each of the beams of light onto a photoreceptor. The damper control also comprises blocking means for blocking at least one of the beams of light. The blocking means is operatively associated with the diaphragm means and is adapted to be displaced relative to the beams of light in response to movement by the diaphragm means. Drive means are additionally provided for moving the damper means in response to pressure variations in the flue.

Abstract: Thermally actuated damper for vents or flues of gas-fired heating appliances having bimetallic slotted blades each of which performs both the sensing and the closing function. In the present invention the slots, which are necessary to enable the bimetal blade to flex in the desired direction, are covered, or eliminated, or substantially reduced for a more complete closure of the damper in the closed position.

Abstract: A housing structure with a single pivoted damper member is provided as a replacement for the draft hood associated respectively with the flue outlet and vent pipe inlet in a gas heater system. The normal flue outlet for the gas system connects to a first passage in the housing and the normal overhead vent inlet connects to a second passage in the housing above the first passage. First ends of the passages adjacent to their connections to the flue outlet and vent pipe inlet are closed off and second ends open out in a common plane. Communicating with the second ends is an ambient atmosphere opening so that under conditions where the second ends of the passages are open, proper exhausting of gases passing up through the flue to the vent takes place. The single damper itself is mounted to swing in a manner to close off both passages simultaneously when in a first position and also isolate these passages from the ambient atmosphere inlet. In this first position, heat is retained in the heater as well as the room.

Abstract: An adapter circuit for retrofitting an oil burner control system with a flue damper includes a source of energy in circuit with the thermostat for energizing the damper motor in response to a call for heat to open the damper. A first relay in the adapter circuit includes a pair of contacts for simulating the operation of the thermostat contacts. When the damper is open, this relay is energized, and its contacts close, simulating the operation of the thermostat after the damper is opened, to energize the burner control circuit, thereby energizing the burner motor and ignition. A second relay in the adapter circuit senses whether the burner motor is energized; and when the burner motor is de-energized, this relay initiates a time delay after which the adapter circuit closes the damper.

Abstract: An apparatus for opening and closing the draft hood discharge opening and vent and fuel line of a fluid fuel-fired heating device such as a domestic water heater. The disclosed apparatus includes a diaphragm-type expansible chamber fluid motor assembly mechanically linked to a damper assembly such that when the heating devices call for heating, the supply of pressurized fuel acts to actuate the motor for opening the damper assembly. The motor assembly also has a pressure output line which operates a fail-safe type of diaphragm valve for controlling flow. This prevents burner operation until after the dampers are open. Additionally, when the supply of fuel is terminated, the motor assembly does not close the damper assembly until after the diaphragm valve stops fuel to the burner.

Abstract: In a flue damper control system, a thermistor 64 responsive to flue temperatures upstream of the damper 12 is incorporated in a trigger circuit for a triac 52 which controls energization and deenergization of the damper motor 17, the damper motor being fully energized only when the flue temperature is below a predetermined value and there is no demand for heat by the thermostat 36.

Abstract: A pivotal vane carrying member secured to the damper for a furnace flue normally maintains the damper by gravity in an open position. An electric motor driven air blower discharges air against the vanes of the pivotal member to pivot the latter and damper to a closed position when no fuel is supplied to the furnace. Otherwise power for the blower motor is shut off and the pivotal member returns by gravity to its normal flue-open position.

Abstract: A shut-off device for installation in the waste gas line from combustion spaces. The device includes a flow-through housing, a shut-off plate mounted in this flow-through housing and adjustable, and a positioning motor arranged on the outside of the flow-through housing for the shut-off plate. The shut-off plate is biased by a spring in a direction toward a first terminal position defined by an abutment and is capable of being adjusted by the positioning motor in a direction toward a second terminal position defined by a second abutment. At least one limit switch is provided for actuation by a control element in the open position of the shut-off plate and serving to initiate operation of combustion spaces arranged upstream from the shut-off device. The positioning motor is a rapidly rotating electric motor having a motor shaft connected with the transmission input of a step down transmission for converting the rotary speed of the motor into a slower speed.

Abstract: An automatic vent damper control mechanism for use on furnaces or the like having a spring loaded open position and an electric motor which drives it to a closed position, against the spring bias, via a gear train. A unique over-travel mechanism is provided which prevents damage to the gear train from occurring when the damper reaches the end of its travel towards its open condition.

Abstract: A chimney cap for closing and venting, selectively, the upper end of the chimney is manually controlled by means of chains or the like from a combustion area, particularly a fireplace, through counterweights and pulleys. Automatic control is determined by a smoke, heat, or incipient fire detector that will operate a hold relay to produce a signal split between a reset timer and double-throw, double-pull switch that is in turn operated by the position of the cap to operate a reversible motor for movement of the cap to its upper vented position upon the detection of combustion products within the chimney. Movement of the cap to its upper position will shield the detector and other electronics from combustion products, and after a timed period, the reset timer will actuate the motor to move the cap to its closed position where it will remain unless the detector again detects the presence of combustion products.

Abstract: An automatic damper means and controls, which provide an exceedingly safe automatic damper for the exhaust duct-work of an associated gas furnace or the like, by automatic control of the damper, and automatic control of the gas supply, with redundancy features for providing exceedingly safe operation.

Abstract: An automatic vent damper for combustion devices such as furnaces which closes the combustion chamber exhaust vent when the furnace burner is off to conserve heat and prevent backdrafts. A damper blade pivotally mounted in the exhaust vent is closed by an electrically-operated damper motor operating against a torsional spring urging the damper plate into the open position, the damper motor being energized whenever burner operation is not in demand by the automatic controls. When the controls call for burner operation, the motor is deenergized and the damper blade moves to the open position under the influence of the torsional spring. A limit switch senses the damper blade achieving the open position and enables burner operation.

Abstract: A control system adapted to be secured to a solid fuel burner, such as a fireplace or a stove, to create and regulate forced fluid heat exchange and forced draft in the burner. The system comprises an electrical draft inducer/damper mounted in the burner flue, a fluid heat exchanger mounted over the burner firebox, and a control apparatus capable of deactivating the draft inducer/damper and the heat exchanger, automatically damping the flue, when combustion in the burner subsides. The control system, including the draft inducer/damper and heat exchanger, may be incorporated with a solid fuel burner, thus comprising a heating system.

Abstract: This invention relates to an automatic damper device for use in exhaust flues, such as flues of combustion devices such as furnaces and water heaters, devices such as air conditioners, and the like, to prevent undesirable loss of hot air or cold air out the flues during periods when no combustion is taking place. The damper has a rotatable damper plate held in normal open position which provides a desired fail safe in the open position assurance. The damper is also adapted to remain in the open position during periods of combustion in the furnace or water heater but otherwise be retained in the closed position to avoid the unnecessary loss of heated air or cooled air.

Abstract: A draft control arrangement for use with a gas-fired heating apparatus. The flow of waste gas through a draft hood of the apparatus is throttled by bimetal element means which responds to temperature change for reducing or enlarging the throttle area. Control means is provided for causing the rate of throttle area change during a certain phase of operation to vary from the rate of throttle area change during other phases of operation.

Abstract: A vent control arrangement for energy conservation having bimetallic damper elements mounted in a draft hood which forms an integral part of the heating apparatus. The bimetallic elements open and close the flow passage for vent gases from the combustion apparatus in response to temperature change. The vent control arrangement is designed for minimum resistance to the flow of vent gases when installed in the integral draft hood. A design without friction surfaces and without transfer of movements or signals between components is used. Opening time is minimized by closeness to the heat source and in one embodiment by alternate bimetal reeds of different initial tension, in other embodiments by alternate orientation, or by different flexivity of alternate bimetal reeds.

Abstract: A conventional forced air furnace is provided with a source of outside air for use in combustion. The amount of outside air admitted to the furnace and the amount of heated air lost through the chimney are regulated by simultaneously operable dampers synchronized with the operation of the furnace. Alternate power circuits and an alarm system for the dampers are provided.

Abstract: The shaft of an oil burner drive motor carries a plate and means responsive to stopping of the shaft for moving the plate axially of the shaft in a direction to close the air intake duct and responsive to starting of the shaft for moving the plate axially in a direction to open the air intake duct.

Abstract: A gas-fueled oven having energy saving capabilities provided by a thermostatically controlled gas supply valve which supplies fuel to the gas burner at cycled intervals, and a flue restricter which is operatively connected with the thermostat to move into closing relation to the oven exhaust flue when the burner is cycled off, thereby retaining within the oven cavity an amount of heat which would normally be allowed to escape through the flue if the flue restricter was not utilized.

Abstract: A furnace ignition and draft control system includes a damper plate movable under control between a closed and an open position. When a call for heat signal is generated, a holding relay is actuated to energize a damper motor to open the damper provided the damper plate was closed when the signal was generated, otherwise the system will not operate. After the damper is run to the full open position and this is proved, a fuel control circuit is actuated to supply fuel to the furnace, and a trial-for-draft period is initiated. A draft controller energizes the damper motor to open the damper if draft is less than a first predetermined value and to close the damper if draft is greater than a second predetermined value. The predetermined draft values define a desired draft range in which the damper is not operated.

Abstract: A flue throttle to control the amount of flue gas or heated air going out the flue from a heating system, by throttling the flue to the minimum amount required while the heat source is on and to change to a further reduced or a complete throttling of the flue when the burner or heat source is off. The heat source referred to throughout this application is from the combustion of fuel through an electric motor driven burner.

Abstract: A thermal damper assembly mounted to substantially close a flue at room temperature is equipped with thermally responsive coils to move the damper to an open position in response to heat generated by combustion. To allow commencement of combustion the damper assembly is equipped with latch means to position the damper open in preparation for combustion, said latch means responding automatically to an adequate advance of said damper toward its fully open position to disable its own latching capability whereby said coils are permitted to substantially fully close the damper assembly without further attention to the latch means, which serves only to releasably position the damper assembly for commencement of combustion. Also illustrated in this application are various position control members for predetermining fully open and substantially fully closed damper positions. Also illustrated in this application are inboard and outboard mountings for the thermally responsive coils.

Abstract: A thermally controlled damper construction for a gas fired combustion apparatus, such as a furnace. The damper has a generally eliptical shape and is mounted on a shaft in the stack or flue for pivotal movement from a closed position, where the damper is located at an angle of approximately 45.degree. with respect to the axis of the stack, to a full open position. One edge of the damper is recessed to provide a vent opening between the damper and the stack and permit venting of gases generated by operation of the pilot light during periods when the furnace is not operating. The damper is moved between the closed and open positions by a bi-metallic element which is located upstream of the damper and connected to the damper by a linkage. When the furnace is operated, the increase in flue temperature will operate the bi-metallic element to move the damper to the open position.

Abstract: An energy conserving device for preventing loss of heat energy from a heater to a chimney by means of a fluid gas heat trap to choke off either chimney draft and/or heated convectional air currents lost to the chimney when the heater is OFF but allowing combustion gasses to vent freely to the chimney when such gasses are generated. The device also acts as a diverter for either up or down drafts from the chimney to direct them away from the heater. In another form when the device is used with a forced air type furnace, the device in addition provides heat interchange between room air and the hot gasses in the trap. This then heated air is drawn into the circulating system of the furnace adding to its temperature while lowering the temperature of the vented combustion gasses, to lessen the heat loss up the chimney.

Abstract: For a vent or flue damper of the type in which the damper is closed by an electrically energized actuator when the furnace is off and the actuator has first biasing means to open the damper when the actuator is deenergized, a second biasing means such as a torsion spring, independent of the first biasing means, is associated directly with the damper shaft and is adapted to always move the damper to an open position in the absence of the actuator.

Abstract: A burner cut-out safety control for a combustion heating device having an automatic exhaust flue damper. The safety controls act to discontinue burner operation in the event the damper actuator device or controls fail, or other flue blockage causes products of combustion to be exhausted through the draft diverter inlet opening. The control is integrated with an existing burner pilot safety circuit and pilot valve to cause the pilot valve to be closed in the event combustion gases begin to pass out of the flue through the draft diverter inlet opening, this condition being detected by a lineal temperature sensor extending about the draft diverter inlet opening, which senses combustion gas spillage by the resultant heating of any portion of the lineal temperature sensor.

Abstract: An automatic flue damper positioned respectively to open and closed positions by means of motive apparatus, such as a solenoid motor, is provided with mechanical means for automatically latching the damper in its open position.

Abstract: A draft control arrangement having bimetallic damper elements mounted in a draft hood and adapted to change shape in response to temperature change to open and close the flow passage for vent gases from a combustion apparatus. The damper elements are positioned in the hood relatively close to the source of hot flue gases to provide faster opening and less tendency for vent gas spillage. When open the damper elements cooperate with stationary walls of the draft hood so that the resulting streamlined passage prevents minimum flow resistance. In certain embodiments the damper elements are arranged to undergo a spreading action during opening movement to achieve a disproportionately large passage for the vent gases during the initial phase of opening. In another embodiment a damper unit is mounted separate from the draft hood and provides the same operating results as the other embodiments.

Abstract: Device for automatic draft control of a furnace having an oil burner, a smoke flue, and an exhaust valve located in the smoke flue, part of said smoke flue comprising a metal tube which is connected with the wall of a chimney, said device comprising a first sensoring device provided on said metal tube and subjected to the influence of the temperature prevailing in said tube, and a second sensoring device provided in said chimney wall, said first and second sensoring devices being connected with the exhaust valve in such a manner that their combined registration is transmitted to the exhaust valve.

Abstract: An automatic damper for closing the flue of a furnace during periods of non-combustion utilizing a pivotally mounted linkage arm spring biased against a motor driven cam to effect rotation of the damper to open and close the flue. Switches, responsive to the position of the damper operate to selectively activate the motor in accordance with the combustion state of the furnace. Provisions are also described for inhibiting combustion in the furnace when the damper is not in an open position.

Abstract: A control system for use with gas-fired appliance installations, such as a furnace, includes a switch responsive to normal draft levels in the vent stack. At the start of a heating cycle, and in the absence of draft, the switch permits a pre-draft enabling circuit to tentatively enable the furnace controller for a predetermined time. The controller opens a stack damper plate and actuates the ignition system and gas valves of the furnace. If draft is not established within the predetermined time, the pre-draft enabling circuit times out and the gas is shut off. If normal draft is sensed within the predetermined time, the draft responsive switch permits the furnace controller to be operated as long as the thermostat calls for heat. If, for any reason, draft subsequently stops, the control system re-cycles itself; and if draft is not re-established before the pre-draft enabling circuit times out, the system deactivates the furnace controller.

Abstract: A control system for a damper installed in the exhaust flue of a furnace, by which activation of the furnace is rendered impossible unless the damper is in its fully open position. The control system achieves that objective by making completion of the energizing circuit of the solenoid that controls flow of fuel to the burner dependent upon closure of a normally open switch that is closed by the movement of the damper to its open position, and by opening the damper with an electric motor that is controlled by a relay energized in response to a call for heat at the thermostat.

Abstract: For an automatic flue damper assembly of the type in which the motor of a clockwork mechanism is energized to hold the damper closed and the mechanism is mechanically biased to move the damper to an open position in the absence of motor energization, a stopping or braking arrangement is provided which applies DC to the motor for dynamic braking as the damper closely approaches its open position. Additionally, the remote possibility of a damper hang-up at an intermediate position resulting from a residual magnetic locking torque is substantially eliminated through the provision of an AC trickle circuit connected to the motor.

Abstract: An apparatus for opening and closing the draft hood discharge opening and vent and fuel line of a fluid fuel-fired heating device such as a domestic water heater. The disclosed apparatus includes a diaphragm-type expansible chamber fluid motor assembly mechanically linked to a damper assembly such that when the heating devices call for heating, the supply of pressurized fuel acts to actuate the motor for opening the damper assembly. The motor assembly also has a pressure output line which operates a fail-safe type of diaphragm valve for controlling flow. This prevents burner operation until after the dampers are open. Additionally, when the supply of fuel is terminated, the motor assembly does not close the damper assembly until after the diaphragm valve stops fuel to the burner.

Abstract: An improved flue damper for isolating furnace from chimney-flue when burner is not operating includes in preferred embodiment a damper plate pivotally mounted within a flue section on a control rod extending through the flue section to bearing support in a bracket spaced from the flue section by a frame affixed to the flue section exterior; a bimetallic strip spiral having inner end affixed on the control rod and outer end detachably looped over a stud extending from the frame rotates the control rod under thermal actuation provided by an electric heating element adjacent the bimetallic strip spiral; a damper control strip on the end of the control rod adjustably affixes a switch plate rotatable therewith and bearing a first mercury switch controlling the heating element circuit and a second mercury switch controlling the furnace burner circuit; stop structure on the bracket limits rotation of the damper control strip and control rod.

Abstract: This flue control assembly is for use with a combustion chamber, such as an oven, having a thermostatically controlled burner valve circuit and includes a damper pivotally mounted in the oven flue for rotation between open and closed positions by an air actuated, movable arm assembly. The air actuated arm assembly is supplied with air from a valve controlled air pump and the valve includes a movable valve element which is resiliently connected to the movable arm and the movable valve element is moved into position to condition the supply of air from the pump by movement of the damper. An electrical switching system connected to the burner valve circuit ensures that the burner valve cannot be actuated unless the damper is in the open position in the flue.

Abstract: A relatively simple automatic mechanical flue damper is provided by a damper plate having a slot extending across a major portion of its diameter with a helically-shaped, temperature responsive bimetal having one end attached to the damper plate at one end of the slot, and its other end attached to a bushing which in turn is fixed relative to the flue in which the damper is situate, with a shaft extending in rotatable relation through a bore in the bushing and having its end opposite the bushing attached to the damper plate, the helical bimetal being responsive to changes in flue gas temperature to rotate the damper plate between predetermined open and closed positions with the shaft rotating to corresponding positions, and at least one of the shaft ends including indicia means to permit observation of shaft and damper rotative position.

Abstract: A draft control arrangement having bimetallic damper elements mounted in a draft hood and adapted to change shape in response to temperature change to open and close the flow passage for vent gases from a combustion apparatus. The damper elements are positioned in the hood relatively close to the source of hot flue gases to provide faster opening and less tendency for vent gas spillage. When open the damper elements cooperate with stationary walls of the draft hood so that the resulting streamlined passage presents minimum flow resistance. In certain embodiments the damper elements are arranged to undergo a spreading action during opening movement to achieve a disproportionately large passage for the vent gases during the initial phase of opening. In another embodiment a damper unit is mounted separate from the draft hood and provides the same operating results as the other embodiments.

Abstract: Apparatus and a method for assuring safe retrofit installation of a flue damper in a hot air furnace. The flue damper is electrically connected to the original furnace control circuit by engaging a flue damper connector with a portion of a printed circuit board containing part of the furnace control circuit. The physical configuration of the adapter and the printed circuit board require removal of a jumper conductor within the printed circuit board prior to connection of the adapter thereby assuring that the flue damper is correctly installed so that it will be in the open position before the furnace may be ignited.

Abstract: A burner cut-out safety control for a combustion heating device having an automatic exhaust flue damper. The safety controls act to discontinue burner operation in the event the damper actuator device or controls fail, or other flue blockage causes products of combustion to be exhausted through the draft diverter inlet opening. The control is integrated with an existing burner pilot safety circuit and pilot valve to cause the pilot valve to be closed in the event combustion gases begin to pass out of the flue through the draft diverter inlet opening, this condition being detected by a lineal temperature sensor extending about the draft diverter inlet opening, which senses combustion gas spillage by the resultant heating of any portion of the lineal temperature sensor.