Abstract: For use with a watering trough fill control valve having float structure located to rise as water is filled into the trough via the valve, and to effect closing of the valve when the trough is filled to predetermined extent, the float structure located to fall as water level lowers in the trough, the float structure controlling a water inlet subject to freezing in closed position in winter, comprising an apparatus operatively connectible with the float structure for biasing the structure, so that it cannot completely close off ingress of water at the inlet as ambient temperature drops below water freezing level; the apparatus including a bimetallic control element.

Abstract: A compact linear operator is provided for a gas valve. The operator may be of modular form for operative combination with combination gas controls of existing design, as by threaded engagement with an existing threaded bore in the control. The operator is suited for directly controlling displacement of a valve or more typically, for controlling displacement of the seat for the regulating spring associated with a servo pressure regulating diaphragm/valve arrangement. The operator includes a controllably heated bimetallic actuator, and a plunger directly or indirectly driven linearly by deflection of the actuator. To enhance compactness of the operator, a displacement-amplifying lever is interposed between the actuator and the plunger. Stops are included for establishing "high fire" and "low fire" limits for the regulated gas pressure.

Abstract: A steady state thermostat is disclosed which employs a magnetic flux coupling technique to obtain a greater stability in its operation, resulting in a significant reduction in fuel costs. The thermostat includes a temperature sensor operated arm and a temperature setting arm pivotally mounted on a common base pivot. A first magnetic field source is mounted on the first end of the sensor arm coincident with a first axis and a second magnetic field source is mounted on the second end of the sensor arm coincident with a second axis. A first magnetic field sensor is mounted on the first end of the setting arm coincident with the first axis and adapted for proximate positioning with respect to the first magnetic field source when the selected orientation of the setting arm corresponds to the desired ambient temperature being higher in magnitude than the existing ambient temperature.

Abstract: A control unit having a condition selector, an actuator and a condition responsive device for actuating the actuator when the condition responsive device senses a condition selected by said selector. A lever is carried by the unit and has opposed ends respectively operatively associated with the actuator and the device. The selector has an adjustable part thereof engageable with the lever intermediate the ends thereof for providing a pivot point for the lever. The adjustable part of the selector is adapted to adjust the differential in the operation of the actuator by the device, the adjustable part providing for a positive differential or for a negative differential.

Abstract: A control circuit for a gas appliance includes ignition and hold circuits, the former providing for series energization of the heater of a thermal fuel valve and an electric igniter positioned proximate the appliance burner port area for ignition of the gas fuel and air mixture exiting the same and the latter providing for direct energization of only the igniter to hold or to maintain the appliance at a warm temperature. Moreover, the fuel valve includes an exterior selector mechanism for facile calibration and/or other adjustment for effective valve operation with either of two different gases at respectively different pressures, such as, for example, natural gas and bottled gas.