GB770272A - Improvements in and relating to refrigerating systems - Google Patents

Abstract

770,272. Refrigerating. GENERAL ELECTRIC CO. Feb. 25, 1953 [Feb. 20, 1952], No. 5285/53. Class 29 [Also in Group XXIX] In a refrigerating system having a high temperature evaporator 3 discharging into a chamber 10 of a header 6 from which chamber refrigerant flows through a passage 30, 18 and pressure reducing valve 9 to a chamber 11 to which is connected a flooded re-circulating low temperature evaporator 4, the discharge of passage 18 is in alignment with the inlet end 13 of evaporator 4 so that the supply of liquid refrigerant enhances the circulation in the lowtemperature evaporator.. The low temperature evaporator 4 comprises a tube depending from the header 6 and having its inlet end 13 opening beneath the normal level 14 of liquid refrigerant in the low pressure chamber 11 of the header, and its outlet end 15 opening into the vapour space of the header. The pressure of the refrigerant in the high temperature evaporator 3 acts on a slide valve element 19 against a pivoted weight 20 to allow refrigerant to pass by passages 30, 18 to the low pressure chamber 11 of the header, the outlet of the passage 18 being directed towards the inlet end 13 of the low temperature evaporator 4 to aid the circulation. The passage 30 is downwardly inclined to reduce the liquid level maintained in the high pressure chamber 10 of the header. To ensure a supply of liquid refrigerant to the end 13 of the evaporator 4 a pipe 25 having one end disposed below the level of the refrigerant is connected to a downwardly inclined orifice 29 in the discharge passage 18. In the assembly of the structure the conduits 3, 13, 15 are brazed to the header, the corrosive flux washed away, the valve 9 then pressed into the header and locked by rolling-in a groove 32 the open end of the header pinched together at 33a and welded by a non-flux method. To adjust the effective pressure of weight 20 and thus the differential pressure the header is rotated about its longitudinal axis to move the weight out of the vertical plane, the pipe connections having sufficient freedom to allow this adjustment. A magnetic element may be fitted in a recess in the weight 20 and the pressure difference varied by a magnetic yoke outside the header, which is of non-magnetic material. Or the weight may include an element of Curie metal so that when the temperature reaches predetermined low value the element becomes magnetic and is attracted towards an exterior magnet to allow the valve to open. Specification 715,600 [Group XXIX] is referred to