Variable capacity refrigeration system

1,105,190. Refrigerating. ALLIED CHEMICAL CORPORATION. 1 Nov., 1965 [2 Nov., 1964], Nb. 46148/65. Heading F4H. In a compression-condensation refrigeration system evaporated refrigerant is adjustably proportioned between two branch lines 19 and 20 leading to the compressor return line 9, the two branches being in heat exchange relationship with high side refrigerant by-pass lines 7B and 7A. The line 7A may pass gaseous refrigerant according to the setting of valves 10 and the line 7B may pass liquid refrigerant according to the setting of valves 8. There may be a single valve 16 controlling the proportions of evaporated refrigerant flow through the branch lines 19 and 20 or there may be two valves 17 and 18 which may be solenoid valves. The valves 8, 10 and 16 or 17 and 18 are controlled through pressure or electric lines 15 by a controller associated with a temperature sensor 13 in the evaporator space 14. When the refrigeration demand decreases, heat exchange between the lines 7A and 20 is utilized, the overriding effect being a decrease of refrigerant density in the compressor return line to reduce the rate of refrigerant flow round the circuit. When the refrigeration demand increases, heat exchange between the lines 7B and 19 is utilized, the overriding effect being a precooling of liquid refrigerant prior to expansion at a valve 5. The valve 5 is controlled by an evaporate, temperature sensor 11. The refrigerant used in the system may be chloropentafluoroethane, octafluorocyclobutane, perfluoropropane, chloroperfluoropropane, and sulphur hexafluoride. Reference is also made by way of comparison to monochlorodifluoromethane, and dichlorodifluoromethane.