Abstract: An induced draft combustion apparatus and its associated control system has a blower located in the exhaust stack or vent which is used to induce the movement of air and combustion products into, through and out of the combustion chamber. A flow-restricting orifice in the exhaust stack near the blower causes a region of higher pressure to exist upstream from the orifice with a region of lower pressure downstream from the orifice. An exhaust gas pressure signal representative of the exhaust gas volume flow rate is sensed on one side of the orifice and is fed back to a modulating gas valve which controls the outlet gas flow from the valve to be proportional to the magnitude of the exhaust gas volume flow rate. By controlling blower speeds and exhaust gas volume flow capacities as related to a selected orifice size, various firing rates for the furnace can be selected, from the design maximum down to various derated levels.

Abstract: A heating system of the type having a combustion chamber with a fuel burner, an inlet for combustion air and an exhaust stack is improved by adding a variable-speed induced draft blower, a flow-restricting stack orifice and a fuel valve sensitive to the exhaust gas flow rate through the stack orifice. The fuel valve turns on at a first predetermined exhaust gas flow rate and turns off at a second predetermined exhaust gas flow rate, which is lower than the first predetermined rate. The fuel valve also supplies fuel at a rate proportional to the exhaust gas flow rate. Sensing of the differential pressure across the stack orifice is used to determine the exhaust gas flow rate.

Abstract: A differential pressure measuring device comprises a capsule including three correspondingly shaped side by side diaphragms secured to each other at their outer edges and encased in a capsule with the diaphragms surrounded by a potting compound which is placed in the capsule in a fluid condition and with pressure being applied to the capsule to hold the outer diaphragms in a limited position, the potting compound is allowed to harden or set.

Abstract: An energy saving thermostat adapted to be connected to a remote temperature conditioning apparatus for controlling the temperature of air in a space maintains a first temperature during a first time period and a second energy saving temperature during other time periods of the day. The thermostat has a visual indicating means so that when a manually settable switch is pushed, a time interval counter means is energized for indicating and storing a series of pulses each indicative of an hour of setback time into a storage means. The thermostat also has a review button for reviewing the stored time by pulsing the visual indicating means for the number of hours of the time period energy saving temperature.

Abstract: Apparatus for electroplating radioactive sources on a member or substrate for use in an ionization type smoke detector device. The substrate is clamped between two members with a chamber adjacent a portion of the substrate. The chamber contains a hollow electrode which is positioned closely to the substrate so that when an electrolyte solution of radioactive material is placed in the chamber and current is passed from the electrode through the electrolyte into a grounded substrate, a deposit of radioactive material is left on the dimple in the substrate.

Abstract: A multistage timer control setback thermostat control system maintaining a normal temperature in a space and during selected time periods a reduced temperature wherein a first stage is a refrigeration heat pump, the operation of which is affected by outdoor temperature, and a second stage is an auxiliary electrical heating source. An outdoor temperature responsive means is connected in the control system to maintain the heat pump energized during the space temperature setback period if the outdoor temperature is below some predetermined value. Additionally, the indoor thermostat has a high limit temperature responsive means for terminating the operation of the heat pump should the space temperature exceed some predetermined value during the space temperature setback period.

Abstract: A load demand control system for limiting the total average electric load over a moving predetermined time interval to an installation having at least one large load device, making use of a timer control which can be selectively operated by an operator upon the need for the operation of the one large electrical load. The timer control first resets the control point of the load demand control of the installation at some low predetermined value. Subsequently, the timer control turns on the large load for a predetermined period of time and after its operation, the timer control maintains the low predetermined value of the load demand control for a further predetermined time period whereby the total moving average electrical load to the installation for the total time interval of the timer control is maintained below a predetermined peak electrical load value set for the installation.

Abstract: A smoke detection alarm system which has at least one detector and alarm in each of the plurality of areas with an interconnection circuit whereby upon the detection of an abnormal smoke condition in any one of the areas, the annunciator or horn of the detector in the area having the abnormal condition is operated with a steady tone and the annunciators of the other detectors in other areas are operated in an intermittent tone so that an occupant of an area can determine by the sound of the tone from the annunciator whether the abnormal condition is in the area in which he is located or in a remote area.

Abstract: A clock thermostat apparatus for controlling the temperature in a space at different temperatures depending upon the time period of the time controlled apparatus has a second temperature responsive apparatus responsive to space temperature for determining the pickup time required to bring the temperature of the space back to normal after a period of setback. When the space temperature drops a small amount, the pickup time for bringing the space back to a normal temperature is short; however, during cold weather conditions when the space temperature drops a large amount, a greater pickup time period is scheduled.

Abstract: An averaging temperature responsive apparatus for use in an air conditioning system to measure the average temperature of air passing through a duct has a tube extending transversely across the air duct. The tube has a series of spaced inlet openings on the upstream side and at least one exhaust opening on the downstream side. A temperature responsive element is mounted adjacent to the exhaust opening. Each of the inlet openings is made by cutting the tube and bending a portion of the tube inward so that upon air entering the inlet opening, the air is directed through the tube in a direction toward the exhaust opening.

Abstract: Apparatus is provided for constructing an induced draft furnace and its control system, to produce an induced draft furnace having increased efficiency. A blower located in the furnace exhaust stack is used to induce movement of air, fuel and combustion products into, through and out of the combustion chamber. A flow-limiting orifice in the exhaust stack in proximity to the blower causes a region of higher pressure to exist upstream from the orifice, with a region of lower pressure downstream from the orifice. A pressure signal representative of the flow rate of exhaust stack gases is sensed on one side of the orifice and is fed back to a modulating gas valve which controls the outlet gas flow from the valve to be proportional to the magnitude of the pressure signal representing exhaust stack flow rate. By selecting blower speeds and flow capacities, various firing rates for the furnace can be selected, from the design maximum of the furnace down to various derated levels.

Abstract: A clock thermostat apparatus adapted for controlling temperature conditioning apparatus maintains a normal control temperature in a space and during certain selected time periods deviating from the normal temperature control by resetting the normal temperature control to some lower temperature for comfort and energy conservation. The clock thermostat apparatus has a manual temperature selection means and a manual temperature deviation selection means for selecting the normal control temperature and the amount of reset or deviation during the selected time period. A connection means is provided between the temperature selecting means and the temperature deviation selection means to turn the temperature deviation selection means to a lower value when the temperature selection means is moved to some predetermined low temperature.

Abstract: A thermostat adapted for controlling heating and cooling apparatuses has a temperature control point adjustment means connected to a temperature responsive switch means for adjusting the control point thereof. A changeover switch means is connected to the temperature responsive switch means for selectively connecting either heating or cooling apparatus to the temperature responsive switch means. A temperature control point limit means is connected to the temperature control point adjustment means so that upon selecting by means of the changeover switch means either a heating or a cooling operation, the temperature control point limit means limits the movement of the temperature control point adjustment means to a first range of movement when heating is selected and a second range of movement when cooling is selected.

Abstract: A safety gas valve for gas burners for providing a "super safe" operation wherein upon the main valve being turned to an off position and the safety valve is held in an operative position by the residual heat of the thermocouple, means is provided for preventing the manual member for opening the main valve until the safety valve returns to the inoperative position.

Abstract: An ionizing type smoke detector device has an output voltage which is compared with a reference voltage and upon the output dropping below the reference, a horn is energized. The reference voltage is normally quite low to reduce the number of false alarms and thus the smoke detector is relatively insensitive to smoldering fires which may require a high sensitivity of the smoke detector device. A timer means periodically modifies the reference voltage to a high value for a short period of time to make the smoke detector more responsive to smoldering fires and yet with the higher sensitivity for the short period of time the number of false alarms are kept at a minimum. Additionally a counter circuit is provided for counting the outputs of the smoke detector over three timing periods and if an output exists for three consecutive periods, an output to the horn is provided.

Abstract: A refrigeration heat pump changeover valve assembly has a cylindrical housing with a slidable valve member in the housing for changing the flow of refrigerant in a refrigeration heat pump system. The evaporator and condenser lines are connected on one side of the housing adjacent each other in line with the axis of the housing. The compressor suction line and discharge or pressure line are connected on the other side of the housing opposite the evaporator and condenser lines adjacent each other at right angles to the axis of the cylindrical housing. The valve member upon moving between a first and a second position upon the operation of a pilot valve connects the suction line to either the evaporator or condenser line when in the first or second position, respectively, and the discharge line is connected to the other line.

Abstract: A flame detecting thermocouple for use with a gas valve to insure that the pilot flame exists before the gas valve can turn on the main burner. The thermocouple has a first rod shaped element which is composed of a high potential side thermoelectric material such as Chromel, Inconel, iron-chromium alloy and a second rod shaped element composed of a low potential side thermoelectric material formed of a 0.7 to 2% yttrium, 45-70% copper and the remainder of the alloy is nickel, and the elements are welded together at their ends to provide a junction which can be heated by a flame to produce a thermoelectric output at the other ends of the element.

Abstract: A gas valve assembly has a main valve connected between the inlet and outlet and controlled by a diaphragm actuator. A two position control valve connects the upper side of the diaphragm to either the inlet gas pressure or the outlet gas pressure to open or close the main valve. A pressure responsive valve means responding to the outlet pressures, controls the exhausting of gas from the upper side of the diaphragm to regulate the outlet pressure. An orifice is contained in the inlet passage to the control valve so that when the control valve is in an on position, the flow of gas to the upper side of the diaphragm is restricted by the orifice. To insure an initial fast opening of the main valve to insure ignition of the combustion device, a flow control valve means is placed in series with the orifice to increase the flow rate of gas when the control valve is moved from the off to the on position to fill the chamber above the diaphragm quickly.

Abstract: A gas valve has a valve seating surface and flexible valve member to insure that the gas flow is terminated when the valve closes. The valve seating surface has a flat portion around an opening and a raised portion around the peripheral opening. A cooperating flexible valve member has a flat portion and a raised portion around its periphery. When the flexible valve member moves against the seating surface, the raised portion of the flexible valve member engages the flat portion of the seating surface and the raised portion of the seating surface engages the flat portion of the valve member to form two concentric series connected seals to insure that gas flow through the valve is terminated.