Constant temperature maintaining refrigeration system using proportional flow throttling valve and controlled bypass loop

摘要

A vapor-compression refrigeration system has a continuously operating compressor, with loading on the compressor varied in accordance with conditions and cooling needs. The system avoids any on/off cycling of the compressor or valves in the system, but instead keeps cooling and bypass valves open to varying and proportional degrees depending upon requirements. The system includes several bypass loops, for bypassing coolant fluid to a proportional degree when a desired temperature is approached in a body to be cooled; and when temperature of return gas to the compressor approaches a limit temperature beyond which the compressor should not operate. In the latter case, cool liquid is injected, while expanding and vaporizing, into the hot gas for cooling, to protect the compressor. The system operates in a very hot environment to effect the maximum cooling possible without exceeding the limits of the compressor, by reducing the refrigerant flow to the evaporator to continue operating at reduced load, reducing more and more of the cooling flow as the desired set point temperature is approached and controlling bypass flow to maintain evaporator pressure or temperature. Proportional flow valves used in the system enjoy long life due to the absence of stressful on/off cycling.