Abstract: A refrigerant flow rate measuring apparatus has a means for detecting the opening degree A of an expansion valve of a refrigeration cycle, a pressure detecting means for detecting the refrigerant pressure Pi at upstream side of the expansion valve, a pressure detecting means for detecting the refrigerant pressure Po at downstream side of the expansion valve, a refrigerant density detecting means for detecting the density .gamma.i of the refrigerant at the inlet side of the expansion valve, a converting means for directly or indirectly converting the values detected by the detecting means into electric signals, and a calculating means for calculating the flow rate of the refrigerant in accordance with the following formula, from the electric signals.

Abstract: A pulsed controlled solenoid flow control valve suitable for use in a closed vapor cycle air conditioning system is disclosed. A pulsewidth modulated control signal is generated for cyclically opening and closing the flow through the expansion valve. The duty cycle of the pulsed control signal determines the average flow rate through the valve. An exponential response control curve is used in conjunction with an integrator offset to obtain a single set point control operating point for all flow rates through the valve, where a given change in the second superheat of the evaporator produces the same percentage change in flow rate regardless of the flow rate.

Abstract: An expansion valve associated with an evaporator in a refrigerating system comprises a valve housing; a closure cap secured to the valve housing; a diaphragm assembly which is disposed in the valve housing and includes a first and a second diaphragm members which are spaced from each other to define a first working chamber therebetween, the diaphragm assembly cooperating with the closure cap to define a second working chamber therebetween, and the first diaphragm member being affected by a refrigerant pressure; a remote sensing bulb; a capillary tube communicating the second working chamber to said bulb; a working gas for moving the diaphragm assembly; a spring urging the first diaphragm member on against the movement of the diaphragm assembly towards the spring; a valve element moved by a difference between the forces caused by the spring and the diaphragm assembly movement; and an inert gas filling the first working chamber with a pressure level higher than a pressure level caused by the spring against the

Abstract: An electronic expansion valve comprising a stepping motor, motion conversion member for converting the rotational motion of the stepping motor to a screw motion, a valve pintle coupled to the motion conversion means to be rectilinearly displaced and having pistons at both ends of the valve pintle, of which the pistons are slidably supported on valve casing members, a valve body formed as an integral part of the valve pintle at an intermediate portion thereof, and a valve seat which has such an outer surface that when the valve pintle is displaced with respect to the valve seat in either direction, the cross sectional area and the shape of a passage defined between the valve seat and the valve pintle are smoothly varied. The valve can be used in refrigeration cycle with a compressor. Stable operation of the refrigeration cycle is obtained.

Abstract: A control apparatus and method is provided for controlling temperatures, temperature differences, or, respectively, liquid levels in refrigeration cycles used for example in heat pumps or refrigeration installations, which is not dependent on the refrigerating medium employed or on the field of application. The flow of the liquid is controlled by two position relay control valves which are electromagnetically actuated and operated by fluid pressure, are suited for large numbers of cycles and are wear resistant. Instabilities in the refrigeration medium cycle are avoided and variations in the end point of the evaporation no longer have a negative influence on the functioning of the control system. The conventionally employed thermostatic expansion valves are replaced by wear resistant two position valves with high frequencies of switching.

Abstract: In a refrigerating system comprising a compressor, a condenser, a capillary tube, and an evaporator, there are provided a check valve on an inlet side of the condenser for preventing a reverse flow of refrigerant from the condenser to the compressor, and a differential valve connected to a delivery side of the condenser. One port of the differential valve is connected with the delivery side of the compressor, so that the differential valve interrupts the flow of the refrigerant from the condenser to the capillary tube upon interruption of the operation of the compressor thereby to improve the operational efficiency of the refrigerating system when the system is started again.

Abstract: The invention relates to a cryopump or heat pump circuit having in series a compressor, a condenser, an expansion valve and an evaporator. The expansion valve is controlled as normally by a sensor which is responsive to the superheating of refrigerant at the outlet of the evaporator. In order to assure sufficient dryness of the evaporator output to make the expansion valve operative, the sensor is connected to a heat source which generates a sufficient amount of heat so that the sensor assumes a temperature corresponding to the set superheating.

Abstract: An arrangement and method of controlling optimum chilled water temperature supplied to a process by a pump, the water being chilled by coolant in a coolant cycle having a compressor and a load valve, comprises first and second sensors for sensing a supply and a return temperature to and from the process. A value is obtained for the amount of work done by the pump and the compressor with that value as well as the supply and return temperature values being supplied to a supervisory control. The supervisory control operates to generate a reference temperature which is a function of the supply temperature but which is either above or below the supply temperature depending on a ratio between the difference in work and a change in the difference between the supply and return temperatures. When the ratio is about zero this indicates the difference between supply and return temperature is at an optimum and the reference temperature is the same as the supply temperature.

Abstract: A two-stage flow restrictor valve assembly is disclosed that is adapted to be inserted in a fluid line to reduce the flow therethrough in two stages. The valve assembly is compactly arranged and comprises a minimum of parts including a valve body, a flow restrictor tube, a power rod, a movable valve assembly operated by the power rod against the spring and a single O-ring for sealing.