Abstract: An improvement in space heating furnaces fueled by gas or liquid for saving heat ordinarily lost through the draft system of such a furnace, comprises a means of automatically closing the air inlet to the combustion chamber as well as the air inlet to the diverter air opening at the flue immediately after cessation of the main burner flame, and also for opening both of the air inlets immediately prior to the ignition of the main burners.

Abstract: A gas furnace employs an exhaust flue damper driven by an electric motor equipped with position indicating switches. A gas flow detector switch supported in the gas line has a vertical passage and a valve member gravity biased into a rest position in which it blocks gas flow through the passage. Fuel flow through the line creates a differential pressure on the valve, raising it above the rest position. Circuitry interconnecting the damper drive and position indicating switches and the gas flow switch with the furnace thermostat and the gas line control valve, positions the damper in a closed position when there is no gas flow to the furnace and in an open position otherwise and prevents energization of the gas flow valve when the damper is closed.

Abstract: The combustion gases of a burner in a heating furnace are discharged to a vent through a draft hood having three ports. The first and second ports communicate with the furnace and the vent respectively and define a first flow path for combustion gases through the chamber of the hood. The third port is open to the ambient atmosphere and defines a second flow path for dilution air through the chamber. Separate temperature responsive, bimetallic elements sense the temperatures in the two paths and cause a vent damper to be moved toward and away from a position in which it closes the second port in response to the sensed temperatures to minimize the flow of dilution air. In a modified embodiment the draft hood is vertically elongate with the bimetallic elements positioned in a zone filling with hot products of combustion for minimizing the flow of dilution air and minimizing spillage of products of combustion during start-up and sudden changes in draft.

Abstract: A flue damper control includes a flue pipe, a damper in the flue pipe and an electro-mechanical control for opening and closing the damper according to thermostatically controlled conditions. The damper control is provided with an adjustment means to adjust the "full" open and "full" closed positions of the damper vane.

Abstract: A damper assembly for conserving fuel consumption in a heating furnace comprises baffle means pivotally mounted in support means arranged to fit in an outlet flue communicating between the furnace and a chimney stack so that the baffle means is movable between a fully open position whereby the flow of combustion gases from the furnace to the stack is substantially unimpeded and a fully closed position providing a restricted flow path for the gases whereby the gas flow to the stack is reduced. Associated wth the baffle means is thermostatic control means responsive to the temperature of the combustion gases for moving the baffle means to the fully open position at a relatively low temperature indicating that the furnace is inoperative and for moving the baffle means to the fully closed position at a relatively high temperature indicating that the furnace is operative.

Abstract: In the present invention, an automatic flue damper located in the vent stack of a household furnace or other apparatus requiring venting is interfaced with a thermostatic control and a fuel supply valve associated with the apparatus so as to maintain a vent passage to the atmosphere normally open during times when combustion is occurring in the apparatus and to close the vent passage at an appropriate time following the termination of combustion in the apparatus. The normally open vent condition is maintained by a damper positioning spring. Vent closure following combustion is accomplished by means of a direct current solenoid. Further included in the interfacing circuitry are a temperature sensing device effective to disable the solenoid, thus opening the vent, upon the appearance of unsafe stack temperatures and a pressure sensor which also disables the solenoid to open the vent stack upon the occurrence of an inappropriate discharge of fuel to the combustion chamber.

Abstract: In a fuel-burning device having a combustion chamber, a burner with a control, an exhaust stack connected to said chamber, an air diverter in said stack and a thermostat connected to said burner control; the improvement which comprises a damper section in the stack downstream of the diverter. The damper is disposed within and journalled upon bearings attached to the damper section. A motor on the damper section has an output shaft connected to the damper and includes a rotary switch on said shaft. An electrical circuit includes a relay switch interconnecting the thermostat, burner control, motor and rotary switch. The motor output shaft is intermittently rotatable through successive arcs of 90.degree., through 360.degree., whereby the damper normally closes the stack preventing escape of room air therethrough when the burner is not operating. The thermostat, when calling for heat, closes the circuit to the motor rotating the damper 90.degree. to open position and successively energizing the burner.

Abstract: A control arrangement for a heating system including a furnace having a fuel-fired burner apparatus and a vent stack with a motor driven damper plate for opening and closing the stack, includes an interlock switch which provides a safety interlock between fuel supply valves of the system and first and second limit switches which control the energization of a drive motor for the damper plate and effect energization of the fuel supply valves of the system, permitting the fuel valves to operate only when the damper plate is in the open position and preventing energization of the fuel valves in the event of a malfunction of either of the limit switches. The interlock switch also permits recycling of the system in the event of a momentary power interruption. The control arrangement may include a stack mounted heat sensor switch which interrupts the energizing path for the fuel supply valves in the absence of heat from the main burner within a predetermined interval of time.

Abstract: A control arrangement for a heating system including a furnace having a fuel-fired burner apparatus and a vent stack with a motor driven damper plate pivotally mounted within the stack, includes a stack damper control circuit including first and second limit switches which permit energization of a drive motor in response to a request for heat, premitting the damper plate to be driven to an open position, and for energizing an interlock switch which prepares an energizing path for fuel supply valves of the system, the first limit switch being operated when the damper plate approaches the open position to complete the energizing path for the fuel supply valves prepared by the interlock switch, and the second limit switch deenergizing the motor when the damper plate is driven to the fully open position. The motor is reenergized at the end of the heating cycle to drive the damper plate to the closed position, and the second limit switch deenergizes the motor when the damper plate reaches the closed position.

Abstract: This invention pertains to apparatus and a method for utilizing waste heat as produced in furnaces, particularly boilers. This apparatus and method is equally useful in hot air furnaces. After heating the water or air the heat that passes into the plenum is caused to pass over and around a heat exchanger which moves air by a blower means through this exchanger into the house or basement. This air can be humidified, if desired. The exhaust stack during the combustion period is open to the chimney. At other times it is closed to prevent heat escape from the boiler. A collecting means is provided for moisture that may collect on the heat exchanger.

Abstract: A flue damper to control the exhaust flow in a flue, wherein a flue damper plate is movable from an open position to a closed position by a solenoid operated plunger and returned from the closed position to the open position by a biasing spring. A damper arm actuates a normally-open limit switch closing the limit switch contacts. The limit switch is in series with normally open contacts of a thermostat, fuel valve, and power source, establishing a fuel system circuit. When the damper plate is in the closed position, the limit switch contacts are open and the fuel system circuit is broken. The plunger solenoid is connected in series with normally closed contacts of the thermostat, and power source, establishing an electrical circuit to close the damper plate. Thus, the circuit to close the damper plate and the fuel system circuit are mutually exclusive so that fuel may not be fired within the flue when the damper plate is closed.

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 positioned in the burner fuel supply line. The motor assembly is mechanically linked to a damper assembly such that the supply of pressurized fuel acts to actuate the motor for opening the damper assembly prior to the motor assembly admitting fuel to the burner. Additionally, when the supply of fuel is terminated, the motor assembly does not close the damper assembly until after the motor assembly stops fuel to the burner.

Abstract: An automatic boiler damper comprising a solenoid valve secured to the pivot axis of a damper included within a stack utilized to vent a heating system. The solenoid is electrically operated upon the closing of a thermostat secured to the stack at a point immediately over the damper location. The damper is provided with a vent hole which enables the thermostat to detect the presence of heated stack gases in sufficient quantity and temperature flowing upwardly from the damper in the closed position, so as to enable the solenoid to open the damper and vent the stack gases through the stack. Heat is conserved thereby and cold drafts are not permitted to enter the stack as a downdraft.

Abstract: An improvement in a system comprising a heat stack, a damper having a vane in said heat stack, actuating means for opening and closing said damper, the actuating means being electrically connected to and responsive to a thermostat in an electrical circuit containing the heating means for generating heat, the by-products from which pass through the heat stack, the improvement residing in that the actuating means comprises an electric motor which is spring biasedly connected to the vane, the electric motor being in a normally "On" position having current passing therethrough and holding said vane against the action of said spring in a closed position. Means are provided to deactivate the motor and allow the spring to return the vane so that the stack is in an open position.

Abstract: A fireplace damper release mechanism for mounting in a fireplace adjacent a fire. The mechanism coacts with a fireplace damper connecting rod to automatically close the fireplace damper when the fire has gone out thereby avoiding the loss of heat from the room through the fireplace chimney.

Abstract: Automatic damper having pivotal semi-circular vanes which are moved to open position by pivotal movement of a longitudinal element disposed along the central gap between the vanes. The movement of the longitudinal element is controlled by a temperature responsive element. Retraction of the longitudinal element causes closing of the vanes. A J-slot arrangement locks the vanes in open position.

Abstract: In the heating chamber of the furnace are a number of heat-absorbing elements which serve as a thermal storage, absorbing some of the heat which is developed during the regular burning cycle and then releasing such heat for additional heating effect. Stored heat is available for additional and therefore more efficient heating. A control system is used to conserve heat by selectively and automatically opening and closing the stack to prevent heat loss in timed relation with the burning cycle and adapted to provide sufficient purge time. The stack valve opens automatically at the commencement of a burning cycle and thereafter automatically closes after a purge interval. In the event of a power failure, the stack valve automatically closes and reopens when power is restored prior to the commencement of any succeeding burning operation.