What 's the application of a back pressure regulation valves that it used in the suction line evaporator ?

Back pressure regulation valves can be used in the suction line, and The application of a back pressure regulating valve is to:

 1. Prevent damage to a liquid chilling evaporator which might result from freezing of the liquid.

2. Prevent frost forming on an air cooling evaporator, where this is close to freezing point, or where a temporary malfunction cannot be permitted to interrupt operation.

 3. Permit two or more evaporators, working at different load temperatures, to work with the same compressor.

 4. Modulate the evaporator pressure according to a varying load, controlled by the load temperature.5. Act as a solenoid valve, controlled by a pilot solenoid valve. their function is to prevent the evaporator pressure falling below a predetermined or controlled value, although the compressor suction pressure may be lower