Ranco Inc.

Ranco Inc. of Delaware

Lee A White

Royal H Sites

A temperature sensor and fabrication technique for making the sensor. An insulating substrate supporting a conductive resistive pattern is laser trimmed until the pattern has a desired resistance. Back and forth movement of the laser is controlled at an automated laser trimming station. The laser trimmer compares the sensed resistance of the conductive resistance pattern with a sensor pattern that has already been precisely trimmed to a desired resistance and is used as a standard.

Method of making a temperature sensor

A demand defrost controller for a heat pump. The controller compares the temperature of an outdoor heat exchange coil with an enable temperature. A timer is activated when the coil temperature is less than the enable temperature. When the timer senses the compressor has run for a predetermined time the controller checks outdoor and coil temperatures to determine if a defrost cycle of the heat pump should be conducted. A defrost cycle is achieved by reversing refrigerant flow in the heat pump system for a predetermined period or until the outdoor heat exchange coil has been heated to a termination temperature.

Demand defrost control method and apparatus

A refrigerant flow reversing valve includes a tubular valve body defining ports for respectively communicating with the discharge of a refrigerant compressor, the compressor inlet and with heat exchangers in the refrigeration system. A valving member is supported by the body for movement with respect to the ports so that in one valving member position refrigerant flows through the heat exchangers in one direction and in a second valve member position refrigerant flows in the opposite direction through the heat exchangers. Refrigerant flow tubes are hermetically fixed to the reversing valve body for directing refrigerant flows through the valve from the refrigeration system. Heat transfer is blocked immediately adjacent the valve body for minimizing heat flow between the valve body and refrigerant in the flow tubes adjacent the valve body.

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Keller, TX, United States of America

Lee A White