Patent GB-912780-A (GB)
Title: A low temperature refrigerated case and method of refrigerating a product area to lowtemperature
IPC: A47F3/04
Filed: 1961-01-04
Abstract: 912,780. Refrigerators. HUSSMANN REFRIGERATOR CO. Jan. 4, 1961 [April 11, 1960], No. 334/61. Class 29. In a refrigerator cabinet a relatively warm, humid portion of the air from the storage space is circulated over a secondary cooler and dehumidifier, the remaining relatively cold dry air by-passing said cooler, and all of the air is circulated over a main cooler before being returned to the storage space. As shown in Fig. 2, the cabinet 10 has a low front wall 12 and a short upper wall 14 defining a permanent front opening 20. Panels 24, 25, 26 and 27, bottom plate 23 and shelf 30 define an airdistribution system and a storage space 29 which is divided by the shelf 30 into upper and lower spaces 29b and 29a. A fan 64 mounted at the rear of chamber 39 below plate 23 forces air over the main evaporator 82 which is located in the rear duct 40, part of the resulting cooled air stream entering the storage space 29 through perforations 45 and 46 in shelf 30 and part through perforations 68, 72, 73, 74 and 75 in the rear and upper ducts 41 and 42. The remainder of the air is discharged through opening 48 to form a curtain of cold air across opening 20. The return flue 47 to fan 64 is divided into inner and outer ducts 52 and 53 respectively, the former leading directly to fan 64 and the latter accommodating a secondary evaporator 83 and fans 59 which are mounted in the end wall 57 of the duct. The outer and relatively warm and humid part of the air curtain together with some room air enters duct 53, is cooled and de-humidified by evaporator 83 and discharged by fans 59 into chamber 39 where it is mixed with the relatively cold and dry untreated air from duct 52. In a modification, Fig. 4, the front return flue is divided into three duets 156, 157 and 158 containing evaporators 164, 173 and 177. Ducts 156 and 157 include subsidiary fans 163, 170, the air from all three ducts being circulated over main cooling means as before by fan 181. Further modifications may include a pivotally mounted damper over the front return flue, operated either by air pressure or a solenoid, and heaters in this flue or in the upper moulding 17 of front wall 12. A label mounting 34 and a light 19 are provided. Defrosting.-The refrigeration and defrosting systems are shown in Fig. 3, in which a compressor 79 supplies condenser 80 and parallel evaporators 82 and 83. A portion of the liquid line 81 and suction line 84 are in heat-exchange relationship at 87. Evaporator 82 comprises a coil 96 having transverse fins 97, on the leading edges of which is mounted a heater 89, the coil 100 of evaporator 83 having fins 101 and 102. The longitudinal spacing of fins 101 and 102 is less than that of fins 97 and heaters 90 to 94 are disposed around the former, as shown in Fig. 2. Defrosting of evaporator 83 is effected more frequently than that of the main evaporator 82 by means of a timer 111 which completes the circuit of heaters 91, 92, 93 and 94, closes solenoid valve 128 in the liquid line to evaporator 83 and opens the circuit of fans 59. Defrosting of the whole system is effected by timer 110 which opens the circuit to the compressor and completes the circuit of heaters 89, 90, 91, 92 and 94. Fans 59 and 64 continue to operate during this period. Drains 107 and 108 are provided for the collection of defrost water. Specification 865,147 is referred to.