Abstract: A flow device for a refrigerant/compressor system is installed between the outlet of an evaporator and the suction port of a compressor. The device includes a floating element that helps inhibit liquid refrigerant from entering the compressor. Under certain conditions where liquid refrigerant discharges from the evaporator, the floating element floats in the discharged liquid. Upon doing so, the float rises to a generally closed position where the float obstructs a main fluid outlet that leads to the compressor. In the closed position, refrigerant can still pass through the flow device, but through a more restricted outlet. To prevent the float from undesirably rising under the impetus of refrigerant vapor flowing at high flow rates, the floating element itself includes a flow-restricting passageway, radial guides, and/or a streamlined shape. The float can be incorporated within a manifold of a multi-coil or multi-circuited heat exchanger.

Abstract: Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system using a dual evaporator, two-stage cycle. The refrigeration cycle includes a phase separator which receives two phase refrigerant from the low temperature evaporator and supplies liquid refrigerant to the pulse width modulated solenoid valve. A liquid level sensor is disposed in the phase separator, and a controller for controlling the duty cycle of the pulse width modulated solenoid valve is provided to receive input from the liquid level sensor. The liquid level sensor can be of the type which provides a continuously variable signal as a function of liquid level, or it can be a liquid level switch which controls valve duty cycle on the basis of whether the phase separator liquid level is above or below a set level. Alternatively, two liquid level switches can be provided.

Abstract: The invention relates to control apparatus for feeding liquified refrigerant to the evaporator of a refrigeration system. A main valve controlled by a differential pressure type servo-element controls the flow of refrigerant to the evaporator. A float type pilot valve has a nozzle and closure member controlled by a float which has a liquid level identical to liquid level in the evaporator. A pilot conduit which extends between the main valve and the pilot valve has first and second throttle units arranged in series. The first throttle unit controls a flow of liquid refrigerant through the pilot conduit to control the main valve. The second throttle unit controls a flow of refrigerant through the pilot conduit which is at least partially in vapor form. This arrangement with two throttle units allows control over a broader proportional range for the settings of the float in the pilot valve.

Abstract: An injector cooler control system which controls the flow of refrigerant from a common receiver that ties a common refrigeration plant to more than one injector cooler systems. The control system limits the amount of liquid refrigerant entering a cooler surge tank by limiting the amount of liquid refrigerant passing from the receiver through an injector valve, thus preventing liquid carryover to the compressor of a common refrigeration plant.