The Trane Company

Dennis A Stanke

Paul C Rentmeester

Paul D Ulland

A temperature control is disclosed for a variable volume air conditioning system of the type wherein electric motor-operated air valve means are provided for varying the volume of relatively warm or relatively cool conditioned air supplied to a conditioned zone. The control includes zone thermostat means for sensing the temperature within a conditioned zone, determining the deviation between a set-point temperature and the zone temperature, and for producing an electrical error signal having a magnitude which varies in a predetermined relationship with respect to said deviation in temperature. Valve motor control circuit means receive the error signal and are operative to energize electric motor-operated air valve means in response thereto so as to vary the volume of conditioned air being supplied to said conditioned zone in a sense to restore the zone temperature to the set-point temperature. Flow limit circuit means receives the error signal and imposes limits thereon related to the minimum or maximum desired flow of conditioned air.

Temperature control for variable volume air conditioning system

A temperature control is disclosed for a variable volume air conditioning system of the type wherein electric motor-operated air valve means are provided for varying the volume and relatively warm or relatively cool conditioned air supplied to a conditioned zone. The control includes zone thermostat means for producing an electrical error signal having a magnitude which varies in a predetermined relationship with respect to a deviation in zone temperature, and changeover circuit means for varying said predetermined relationship in order to accommodate changeover between heating and cooling, as sensed by duct temperature sensing means. The control further includes flow limit circuit means for imposing limits upon the maximum and minimum desired flow of conditioned air through the air valve means.

Apparatus are disclosed for sensing the velocity of a fluid stream, as may be flowing in a duct, pipe, or the like, which fluid stream exhibits variations in its temperature under different operating conditions. The apparatus includes a first probe which is exposed to the fluid stream and includes first temperature sensing means for sensing the temperature of the fluid stream. A second probe is provided which is disposed within the fluid stream and includes at least a portion constructed of a thermally conductive material. Heater means are disposed in thermally conductive relationship with said thermally conductive portion, and second temperature indicative of the temperature of said heater means. Third temperature sensing means are provided for sensing the temperature of the thermally conductive portion of the second probe at a point removed from the heater means, which temperature is a function of the heater means temperature, the fluid temperature, and the velocity of the fluid flowing thereover. In order to compensate for variations in the fluid temperature, heater control circuit means are provided for receiving temperature signals from the first and second temperature sensing means and for controlling the heat output of the heater means so as to maintain substantially constant the temperature difference between the fluid and heater means. Velocity output circuit means are provided for receiving the fluid temperature signal from the first temperature sensing means and the second probe temperature signal from the third temperature sensing means and for producing a signal related to the differences between said temperatures, which signal is related to the velocity of the fluid stream.

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La Crescent, MN, United States of America

Dennis A Stanke