Abstract: A refrigeration system for food display cases is disclosed, having a heat reclamation coil, to which hot gas discharged by the system's compressors may be diverted in accordance with the conventional practice, to provide heat energy usable for heating and/or controlling the moisture content of the interior store area. An improvement in such heat reclamation systems is disclosed, in that the output of the heat reclaim coil is continuously sensed to determine whether it is in an all-liquid condition, or alternatively, a mixture of liquid and gas. If the former, valving is automatically operated to bypass the liquid output from the heat reclaim coil around the system's condenser to the liquid line downstream from the condenser, so that the heat reclaim coil functions as the system's condenser in these circumstances. If the output from the heat reclaim coil is a gas-liquid mixture, it is returned to the input side of the system's condenser to reduce the energy required for normal condenser operation.

Abstract: A refrigerating system of the type used in supermarkets for refrigerating foods merchandised in refrigerated display cases, utilizes a control valve sensitive to pressures in a surge receiver and the liquid line. The valve opens whenever the receiver pressure drops below that of the liquid line more than a predetermined amount, to force hot gas from the compressor discharge line into the receiver. An elevation of the receiver pressure results, until the predetermined pressure differential between the liquid line and the receiver is re-established.

Abstract: Disclosed is a means for preventing "logging" of receivers, that is, the excess filling of a receiver with liquid in a refrigeration system of the type in which a compressor, a condenser, and one or more evaporators are connected in a closed cycle in association with a surge receiver. Communication between the discharge side of the compressor and the receiver incorporates a valve of the differential pressure regulating type, having means sensitive to the relationship of pressures established and maintained in a liquid line extending from the condenser to the evaporator and in the compressor discharge line extending from the compressor to the condenser, respectively.

Abstract: A system for refrigerating food products utilizes a saturated gaseous refrigerant, commonly called "cool gas" for defrosting an evaporator or set of evaporators. When defrost is to occur, the saturated gaseous refrigerant flows from a receiver through the evaporator or set thereof being defrosted. A differential pressure control switch operates to prevent flow of refrigerant to the receiver from the liquid supply line through which said refrigerant normally flows from the condenser to the evaporators. The flow from the liquid line to the receiver is prevented whenever the pressure in the liquid line exceeds the pressure in the receiver by a predetermined value.

Abstract: A defrost control scans, in a predetermined sequence, the several evaporators of a refrigeration system of the type that is installed in a supermarket and that typically comprises a series of refrigerated food display cases in which the evaporators are mounted. Individual to each evaporator is a defrosting means and a sensing device that operates to put the defrosting means in a standby, ready-to-operate condition whenever it senses that the evaporator is in need of defrost. When the control means reaches, in the scanning sense, an evaporator whose defrosting means has been placed in a ready-to-operate condition, it acts to initiate actual operation of the defrosting means associated with that evaporator. In these circumstances, the scanning of evaporators that follow in the predetermined sequence is temporarily arrested. This assures against overloading of the defrosting means, which may typically be of the "hot gas" type, and hence particularly sensitive to overloading.

Abstract: A refrigeration system including at least one compressor, a condenser for receiving hot gaseous refrigerant from the compressor and condensing same, a discharge line for supplying hot gaseous refrigerant from the compressor to the condenser, a plurality of expansion valves associated with a plurality of evaporators, a liquid line for passing condensed refrigerant from the output of the condenser to the expansion valves and evaporators, a return line extending from the evaporators to the input of the compressor to supply refrigerant thereto, a receiver for holding a reservoir of refrigerant, a bypass line connecting the receiver to the liquid line, a hot gas defrost means for selectively passing hot gaseous refrigerant through one or more of the evaporators for defrost and a balancing line operable during defrost responsive to a pressure within the receiver greater than within the discharge line to provide fluid flow communication therebetween to equalize refrigerant pressure between the receiver and discharge