DEFROSTER WITH AUXILIARY HEATER FOR DISPLAY CASES

• US 3,839,879 A
• Filed: 05/04/1973
• Issued: 10/08/1974
• Est. Priority Date: 05/04/1973
• Status: Expired due to Term

• Current Assignee: Howard W. Redfern, William P. Coleman
• Original Assignee: Howard W. Redfern, William P. Coleman
• Inventors: Redfern, Howard W., Coleman, William P.
• Primary Examiner(s): Perlin, Meyer
• Application Number:
  US05/357,093
• Time in Patent Office: 522 Days
• Field of Search: 62/151,155,156,196,197,278,276,275
• US Class Current: 62/197
• CPC Class Codes: F25B 2400/22 Refrigeration systems for supermarkets
• CPC Class Codes: F25B 47/022 hot gas defrosting

Abstract

An auxiliary heating device for use in defrosting the evaporator unit in a refrigeration system such as employed in a low temperature display case, such as those found in supermarkets and other stores in which products are stored in low temperature cases but are displayed in a manner for observation by customers. The auxiliary heater is installed by connecting it into the liquid refrigerant line between the condenser and evaporator thereby eliminating the necessity of installing a separate bypass line from the compressor to the evaporator, such as would be necessary if only hot gas refrigerant from the compressor is bypassed into the evaporator during the defrost cycle. The expansion device is also bypassed so that the hot gas refrigerant may bypass the expansion device directly into the evaporator.

Claims

1. In a refrigeration system including a compressor, a condenser, an expansion device and an evaporator arranged in series relation with the condenser being connected to the expansion device by a liquid refrigerAnt flow line, that improvement comprising an auxiliary heater connected in bypass relation to the liquid refrigerant flow line, said auxiliary heater being connected into the liquid flow line in bypass relation between the condenser and expansion device and including a normally open valve in the liquid flow line which is closed during the defrost cycle and a normally closed valve connecting the inlet side of the auxiliary heater with the liquid flow line between the condenser and the normally open valve in the liquid flow line and a normally closed valve on the discharge side of the heater communicating the discharge side of the heater with the liquid flow line between the normally open valve in the flow line and the expansion device, and bypass means associated with the expansion device for bypassing hot gaseous refrigerant around the expansion device into the evaporator.

2. The structure as defined in claim 1 wherein said bypass means for the expansion device includes a bypass line having a normally closed valve therein which is open during the defrost cycle thereby enabling the hot gaseous refrigerant to bypass the expansion device during the defrost cycle.

3. The structure as defined in claim 2 wherein the compressor and condenser are located remotely of the evaporator such as exteriorly of a building when the evaporator is in a display case for food products thereby enabling installation of the auxiliary heater and expansion device bypass adjacent the evaporator with a minimum of additional line incorporated into the system.