Patent GB-1026380-A (GB)
Title: Purging apparatus for a refrigeration system
IPC: F25B43/04
Filed: 1965-02-24
Abstract: 1,026,380. Refrigerating. TRANE CO. Feb. 24, 1965 [Sept. 29, 1964], No. 7981/65. Heading F4H. The pressure difference between the high and low pressure sides of a compression refrigerating system is utilized to provide the driving force for a pump arranged to withdraw non-condensible gases from the system condenser. As shown, the pump comprises one end 13 of a doubleended piston 11 which is freely movable in a housing 10 and has a larger upper end 12, spaces 14, 15 and 16 being defined in the housing by ends 12 and 13. Space 16 communicates through line 24 with the upper part of condenser 2 and through line 29 with a separating chamber 32 while space 15 is in permanent communication with the evaporator 3 through line 20. A valve member 38 having a peripheral groove 39 is movable in a housing 37 between its illustrated position, in which the groove establishes communication between chamber 14 and a line 18 leading to the lower part of the condenser, and a second position in which the groove permits communication between chamber 14 and a line 22 leading to chamber 15. In operation, high pressure fluid from line 18 is admitted to chamber 14 to cause piston 11 to move downwardly so that end 13 ejects gas and vapour from space 16 to line 29. End 12 then clears a port 44 in the housing so that high pressure fluid from chamber 14 passes through a line 42 and acts on the righthand end of valve member 38 to move the same to the left. Chamber 14 then communicates via line 22 with chamber 15 which is at evaporator pressure so that the high pressure fluid admitted to chamber 16 from line 24 causes the piston 11 to move upwardly. This movement continues until end 13 clears a second port 45 in the housing and high pressure fluid is applied through line 43 to the left-hand end of valve member 38 causing the latter to return to its original position. A cooling coil 33 is provided in separating chamber to condense water and refrigerant vapour, the water floating on the refrigerant being removed by tap 34 and the refrigerant being returned to the evaporator via float valve 35 and line 36. Non-condensible gases are vented from chamber 32 through relief valve 64. For purging the system when the compressor is not operating, valves 47 and 48 in lines 18 and 20 are closed and a high pressure gas source 56 is connected to line 18. Operation of the pump then proceeds as before except that gas supplied to chamber 15 from line 22 is vented to atmosphere through line 58 instead of returning to the evaporator. Under normal operation a valve 53 controlled by a diaphragm 51 is arranged to open line 18 automatically when the pressure of the non-condensible gases in the condenser reaches a predetermined value. In the embodiment of Fig. 2 (not shown), the valve 66, which performs the same function as valve 38 above, is moved vertically between its two positions by flanges 72, 73 formed on a rod 71 attached to piston 11. Alternatively, the valve is moved when the ends of a slot formed in rod 71 engage a pin on the valve (Fig. 3, not shown). In a further modification (Fig. 5, not shown), the valve member 86 is moved downwardly by fluid pressure when it is engaged by a bar 88 on the upper side of piston end 12.