ARRANGEMENT FOR CONTINUOUSLY CONTROLLING THE CAPACITY OF A REFRIGERATING MACHINE
Arrangement for continuously controlling the refrigerating capacity of a refrigerating machine, comprising a closed refrigeration cycle with evaporator (3), compressor (5) and condenser (2). Instead of an expansion valve, an electronically controlled control valve is proposed. Control parameters of the medium to be cooled are compared with predetermined target values in a control device (RR). The control valve is set in function of the difference between control parameter and target value. The valve setting governs the flow of refrigerant and hence the corresponding refrigerating capacity. To achieve optimal filling of the evaporator at full load, an additional control device (DR) monitors the minimal difference between suction gas temperature and evaporating temperature. To prevent an excessive drop in evaporating pressure under partial load, an automatic hot gas bypass control device (7) arranged between the high-pressure line and the evaporator feeds substitute gas to the supplier immediately the suction pressure falls below a given value. To protect the compressor from excessively high temperatures, the suction gas control device (RS) opens the control valve until the suction gas temperature falls to the permissible value.