VAPOR-COMPRESSION REFRIGERATING PLANT WITH THROTTLE VALVE REGULATOR OF COOLING AGENT FLOW RATE Russian patent published in 1995 - IPC

FIELD: refrigerating engineering. SUBSTANCE: refrigerating plant consists of main capillary tube, additional capillary tube 2, heat exchanger 3, low-capacity electric heater 4, control unit 5, resistance thermometers 6 and 7, evaporator 8, condenser 9 and compressor 10. Main capillary tube made in form of coil and connecting evaporator 8 with condenser 9 is used as one chamber of heat exchanger 3; other chamber of this heat exchanger is connected to the loop between outlet of additional capillary tube 2 and suction line of compressor 10. Inlet of additional capillary tube 2 is connected with outlet of condenser 9 and additional capillary tube 2 is mounted in thermal contact with electric heater 4. Under steady-state operating conditions, magnitude of vapor over heat at the outlet of evaporator 8 measured by means of resistance thermometers 6 and 7 coincides with preset value. In case of change in the operating conditions, control unit 5, gives signal for changing power of heater 4 by the difference of boiling point and steam temperature at outlet of evaporator 8, thus changing resistance of additional capillary tube 2 and supply of cooling agent to evaporating chamber of heat exchanger 3. Change in amount of cooling agent fed to evaporating chamber cause change in cooling of main flow throttled in main capillary tube and consequently change in flow rate in the cycle; as a result, normal filling of evaporator 8 is restored (preset magnitude of steam superheat). At maximum magnitude of condensing pressure, main capillary tube 1 fully ensures normal filling of evaporator 8 with cooling agent. In this mode of operation, electric heater 4 ensures complete locking of additional capillary tube 2 with steam plug. When maximum flow rate of cooling agent is required in the cycle, heater 4 is switched off. EFFECT: enhanced efficiency. 2 cl, 4 dwg