Abstract: A hydronic heating system having a source of hot supply water and a reservoir of cooler return water, a supply water line from the source, a return water line to the reservoir and at least one heating loop through which water flows from the supply line to the return line, a three-way valve for feeding return water from the return water line to the supply water line to reduce the temperature of water flow to said heating loop and a valve feedback controller for varying the temperature of water flow to the heating loop, has an input to the valve controller representative of outdoor temperature, so that the temperature of water flow to the heating loop is increased or reduced when outdoor temperature falls or rises, respectively.

Abstract: This thermostatic expansion valve (12) is intended for use in a refrigeration system (10) which includes a compressor (14), a condenser (16) and an evaporator (18). The valve (12) includes a valve body (20) having an inlet (26) and an outlet (28). A valve port (34) and a valve element (38) are disposed between the inlet and outlet. Upper and lower diaphragm assemblies (24, 25) are provided at each end of the valve (12) connected to associated sensing bulbs (56, 58) at the inlet and outlet respectively of the evaporator (18). A push rod assembly (40) operatively interconnects the upper and lower diaphragm assemblies (24, 25) and modulates the valve element (38) in response to the change in differential temperature across the evaporator. A compression spring (36) acts directly on the valve element and provides an adjustable feature.

Abstract: A device and method for cooling an internal combustion engine is disclosed in which a simple control circuit constructed of relatively inexpensive components enables the rotational speed of an electric motor employed in the cooling device to be controlled in adaptation to various temperature levels of a cooling circuit. The control circuit includes a power semiconductor which is used to drive the electric motor in certain speed ranges associated with predetermined temperature levels. The control circuit also incorporates a bypass circuit that permits the electrical motor to be driven in particular speed ranges without the use of the power semiconductor. Thus, the electric motor can be driven at one hundred percent of its speed capacity by eliminating a voltage drop associated with the power semiconductor.

Abstract: The interior of two metallic bellows is in fluid connection through capillary tubes with temperature sensors. The temperature sensors are located in places whose relative temperature difference should be determined. In the presence of a temperature difference two springs, each fixed between one of the two metallic bellows and a reference indicator, are pressed together whereby the reference indicator is displaced from its neutral position. The magnitude of this displacement is a measure of the temperature difference and is used by means of switching or recording mechanisms to activate a measuring, controlling, regulating or recording process.

Abstract: A non-electrical thermo-mechanical control system for a hot water heating system having a modulating burner in the boiler. The thermo-mechanical control system simultaneously controls fuel and air supply to the burner in dependence on the temperature difference between forward water temperature to the radiators and return water temperature from the radiators.

Abstract: Control devices for heating installations are disclosed, which heating installations are provided with thermostat controls. The control devices sense the temperature of the heating medium, e.g., water, to be passed to the heating installation and to be returned therefrom. The temperature difference actuates a control for mixing or directing the flow of the medium in the desired volumes. Use is made of control pistons and expansion material to provide control devices which are particularly capable of optimum energy utilization.

Abstract: Thermal actuating or like apparatus in which a sight conduit is comprised in a valve housing enabling the changing position of a thermal actuator within the housing to be observed from outside the housing. A fiber optic device acts as the sight conduit and provides for a display externally of the housing of color coded or like markings on the actuator. In one aspect thereof, the invention makes possible a substantially continuous comparison of the operations of redundant actuators so that an operator or user of the apparatus may be alerted to failure of one of the actuator units.

Abstract: A thermostatically responsive valve bypass mechanism includes a piston slidably mounted in a bypass channel through a valve member. The piston is normally spring biased to a first closed position. A heat transmissive probe is attached to the valve member and includes a series of thermostatic actuators mounted in opposed relation to the spring biased piston. The actuators expand in response to increased temperature and force the piston to an open position whereby fluid flow occurs through the bypass channel.

Abstract: A fluid mixing valve construction having a housing provided with a pair of inlets respectively interconnected by a pair of valve seats to an outlet and with a valve member operated by a condition responsive unit for controlling the valve seats in accordance with the condition of fluid passing to the outlet and sensed by the condition responsive unit. A second condition responsive unit is operatively interconnected to the valve member to close one of the valve seats with the valve member if the first mentioned condition responsive unit does not close the one valve seat with the valve member even though the same is sensing a condition that would require the first mentioned condition responsive unit to close the one valve seat whereby the fluid mixing valve construction is substantially fail-safe.

Abstract: A thermostatic ventilator operator has a thermostatic actuator consisting of a pair of tubes telescoped together with a plurality of thermally responsive power elements arranged coaxially therein. An operating lever is pivoted on a mounting bracket. The thermostatic actuator is pivotally connected to the mounting bracket and to the operating lever with one of the pivots being slidable in a direction normal to its axis. A pair of extension springs bias the slidable pivot in one direction.

Abstract: The invention relates to apparatus for heating and/or cooling a room which is large enough to require at least two heat exchanger units. Controls are provided which dependingly relate the outgoing air stream temperatures of the heat exchangers to avoid the causing of drafts in the room. One of the heat exchangers is a guide unit and all others are follower units. Each heat exchanger has its own individual control such as a valve for admitting heat exchange fluid to the unit. The guide unit has associated room temperature sensor and setting devices for controlling its individual control. Each follower unit has a pair of temperature sensors for jointly controlling its associated individual control. One sensor of each pair is in the outflowing air stream of the guide unit and the other sensor of the pair is in the outflowing air stream of the associated follower unit.

Abstract: A flame probe for use in an automatic pilot ignition system includes both a thermally responsive flame switch and a sensing electrode located in the flame for use in a flame conductivity sensing circuit. Separate conductive paths are provided for the flame switch and for connection to the sensing electrode and the conductive paths are completely insulated from each other.

Abstract: A lead-lag compensated gas-filled temperature sensor having an output which essentially matches, without error, the temperature of a flowing airstream in a gas turbine engine during both transient and steady state conditions comprises a pair of gas-filled temperature probes disposed in the airstream and filled with a gas which expands in response to temperature changes in the airstream at different rates, a pressure responsive means having opposite sides in closed fluid communication with the sensors for compensated movement in one direction and valve means disposed adjacent the pressure responsive means controlled by movement of the pressure responsive means to vary the hydraulic pressure in a system to be controlled.