Abstract: In a space thermostat having a control lever for setting the temperature set-point, a force producing means clamps the control lever to the thermostat casing through an elongated slot in the casing. A hollow, rigid thin-walled nut, a compressible anchor ring, and a screw cooperate to provide means for adjusting the value of the clamping force to a value which enables manual movement of the control lever, upon application thereto of a desired force, to a different temperature set-point. The clamping force is further adjustable to a value which prevents manual movement of the control lever when it is desired to provide a locked condition wherein the control lever cannot be manually moved.

Abstract: In a direct ignition gas burner control system wherein two valves are connected fluidically in series with the burner, a make-before-break thermostatically actuated switch is effective, when a set of "cold" contacts are made, to energize an electrical resistance igniter and to open a first of the two valves which opening enables a pressure actuated switch to close its contacts. When the igniter is above a temperature sufficient to ignite gas, the thermostatically actuated switch makes a set of "hot" contacts while its "cold" contacts are still made. In this intermediate contact position, a second of the two valves is opened, allowing gas to flow to the burner. Continued energizing of the igniter causes the thermostatically actuated switch to break its "cold" contacts, effecting de-energizing of the igniter. When the "cold" contacts are open, the pressure actuated switch provides a hold-in circuit for the valves.

Abstract: A two-piece compression fitting comprises a driving screw and a symmetrical sleeve adapted to be pre-assembled to a threaded receptacle for later connection of coupling tubing. One end of the driving screw is provided with a thin-wall extension for accepting a central cylindrical portion of the sleeve in a press-fit manner so as to provide and maintain co-axial alignment of the inner bores of the screw and sleeve whereby the coupling tubing can be easily inserted therethrough.

Abstract: A timer controlled space thermostat includes a battery operated timer and charging circuit means for continuously charging the battery. The charging circuit means includes a miniature transformer having two primary windings and one secondary winding wound on a single core. When a thermostat switch therein is closed to effect energizing of space conditioning apparatus, one of the primary windings induces a stepped-up voltage and stepped-down current in the secondary winding to effect charging the battery. When the thermostat switch is open, the other primary winding induces a stepped-down voltage and stepped-up current in the secondary winding to effect charging the battery.

Abstract: A gas burner control system wherein a burner is directly ignited by an electrical resistance igniter includes a pressure actuated switch effective to permit automatic re-cycle of the system in the event of an electrical power interruption or a gas pressure failure, and to prevent such automatic re-cycle in the event of an ignition failure.

Abstract: An oil burner primary control in an interrupted ignition burner control system includes a miniature coupling transformer for controlling operation of the igniter. The gate circuit of a flame responsive switch is effective, in the absence of a burner flame, to generate a plurality of gating pulses at a frequency substantially greater than line frequency. The flame responsive switch is cyclically gated on by the pulses for energizing a safety switch resistance heater. The primary winding of the coupling transformer is connected in the gate circuit of the flame responsive switch and is responsive to the gating pulses to induce voltage pulses in its secondary winding which is connected in the gate circuit of an ignition switch controlling the igniter. At least one of the pulses occurs sufficiently early in each half cycle of the sine wave alternating current appearing at the ignition switch so that the ignition switch conducts during essentially all of the sine wave, as long as there is no burner flame.

Abstract: Upon a call for heat, gas flows to a pilot burner and a storage capacitor begins to charge. When sufficiently charged, the storage capacitor effects the opening of a valve controlling flow of gas to a main burner disposed in igniting relationship with the pilot burner. A hold-in circuit maintains the main burner valve open once it is opened. Circuit means connected in circuit with the storage capacitor and spark generating circuit means is responsive to the presence of charging current to the storage capacitor for preventing sparking until the storage capacitor is sufficiently charged to effect the pull-in of the main burner valve upon discharge, and is subsequently responsive to the presence of a hold-in current for terminating sparking.

Abstract: A gas valve device includes an integral drip leg and filter, positioned upstream from valve means contained therein, for collecting and removing liquid and solid impurities from a gas stream. The drip leg and filter includes a fine-mesh screen of significantly larger cross-sectional area than an inlet opening through which the gas stream enters the gas valve device. The screen is positioned at an angle to cause solid particles to be deflected away from the screen. Clean-out means is located between the inlet opening and the screen for collecting and removing the accumulated liquid and solid impurities. In a preferred embodiment, a detachable cover can be removed to enable cleaning or replacing the screen.

Abstract: A gas burner control system utilizes an electrical resistance igniter to ignite a main burner. Electronic sensing means is located adjacent the burner and adjacent a portion of the igniter where opposite voltage polarity exists between the igniter and sensing means. Current flows from the igniter to the sensing means when the igniter is heated above ignition temperature. Circuit means is responsive to such current flow to de-energize the igniter and enable gas to flow for a timed trial ignition period, the igniter having sufficient mass to remain at or above ignition temperature for the trial ignition period. When ignition occurs, the circuit means is responsive to current flow through burner flame from the sensing means to the burner to maintain gas flow.

Abstract: An oil burner primary control in an interrupted ignition system includes therein circuit means responsive to burner flame for initiating energizing of an ignition transformer in the absence of burner flame and for maintaining energizing thereof for a short time period beyond the time at which the burner flame appears.

Abstract: A gas burner control system including a main burner and a pilot burner for igniting the main burner wherein the pilot burner is ignited only when the thermostat is calling for heat and gas is permitted to flow to the main burner only after the existence of a pilot burner flame adequate to ignite the main burner has been proven. A pressure actuated switch is effective, following an electrical power interruption or a failure of or an appreciable reduction in gas pressure, to prevent the resumption of gas flow to the main burner until a pilot burner flame adequate to ignite the main burner has been re-established.

Abstract: A gas burner control system including a main burner and a pilot burner for igniting the main burner wherein the pilot burner is ignited only when the thermostat is calling for heat and wherein a normally closed bimetal operated safety switch is effective to provide a trial ignition period for igniting the pilot burner. An electrical resistance heater for effecting opening of the safety switch is in the gate cicuit of a solid-state switch and is energized in the absence of pilot burner flame. The solid-state switch, when conducting, is effective to complete an electrical circuit through the safety switch to open a first valve and initiate gas flow to the pilot burner. When pilot burner flame exists, the resistance heater is de-energized, the first valve is held open by means including a switch responsive to gas pressure downstream from the first valve, and a second valve, fluidically in the series with the first valve and controlling the flow of gas to the main burner, is opened.

Abstract: A timer controlled space thermostat includes a timer movement energized by a rechargeable battery. A first timer operated switch is in circuit with temperature responsive switching means and space conditioning apparatus control means and is operative to alternately control operation of the space conditioning apparatus control means at one and then the other of two different levels of temperature. A second timer operated switch is in circuit with the space conditioning apparatus control means and with circuit means for recharging the battery and is cyclically actuated to an open position to ensure complete de-energization of the space conditioning apparatus control means and to a closed position to enable the battery to be recharged.

Abstract: A timer controlled space thermostat includes a timer, a rechargeable battery for providing the electrical power to operate the timer, circuit means for recharging the battery, and two single-pole, double-throw temperature responsive switches. One conductive position of each switch enables the energizing of space conditioning apparatus control means, the other conductive position of each switch enables the energizing of the recharging circuit means, and the short timer period incidental to the movement of the switch between the conductive positions provides a sufficient time to ensure de-energizing of the space conditioning apparatus control means prior to the energizing of the recharging circuit means.

Abstract: An electromagnet with terminal means for series connecting the electromagnet, a conventional thermocouple, and an external safety switch. One end of a first terminal is adapted to provide low contact resistance when connected to the hot side of the thermocouple and the other end of the first terminal is adapted to be connected to the safety switch. Separated from the first terminal by an insulative base and integral with the base to which a yoke and winding are secured, are a second terminal, adapted to be connected at one end to the safety switch and connected at its other end to one end of the winding, and a third terminal, adapted at one end to be connected to the housing of a control device in which the electromagnet is assembled and connected at its other end to the other end of the winding.

Abstract: A burner control system for a hot water boiler is responsive to both outlet water temperature and return water temperature to provide a relatively constant outlet water temperature regardless of variations in heat output requirements. A first thermistor responsive to return water temperature is effective to provide on-off control of gas flow to the burner. A second thermistor responsive to outlet water temperature is effective to vary the rate of gas flow to the burner so as to maintain a predetermined outlet water temperature. A timing circuit is effective each time the burner is turned on to delay a high rate of gas flow to the burner.

Abstract: A space thermostat for controlling the two-stage operation of both heating and cooling apparatus includes two single-pole, double-throw mercury type switches operatively connected to a single bimetallic coil. One switch energizes stage one of the heating apparatus when tilted in one direction and energizes stage two of the cooling apparatus when tilted in the other direction. The other switch energizes stage two of the heating apparatus when tilted more in the direction which effected the energizing of stage one of the heating apparatus and energizes stage one of the cooling apparatus when tilted less in the direction which effected the energizing of stage two of the cooling apparatus. The switches are adjustably mounted with respect to each other so that the differential between stages can be adjusted to be the same as the differential of each switch.

Abstract: A spark ignition circuit begins producing sparking pulses and a storage capacitor begins charging upon closure of a space thermostat. An electromagnetically operated valve controlling gas flow to a burner is energized sufficiently to open only upon discharge of the capacitor and a parallel holding circuit holds open the valve and prevents recharging of the capacitor.A counting circuit, including a first monostable multivibrator, responds to each sparking pulse to effect incremental charging of a capacitor. Circuit means, including a programmable unijunction transistor and a second monostable multivibrator, responds to each occurrence of a predetermined charge on the capacitor to produce an output pulse comprising negative and positive signal voltages occurring in that order. Switching means responding to the positive signal of the first occurring output pulse effects the discharge of the storage capacitor and completion of the holding circuit, whereby the valve is open.