Digital control valve for refrigeration system

A kit for retrofitting a refrigeration or air conditioning system having a scroll compressor to use a refrigerant with a high gas discharge temperature, comprising:

• a temperature sensor for sensing the temperature of the discharge gaseous refrigerant in the discharge line of the scroll compressor;
• an injection valve for controlling injection of liquid refrigerant into the suction line of a compressor of the refrigeration system;
• a set of fluid injection pills having various orifice sizes therethrough for attaching to said valve;
• and
• a controller for selectively actuating said valve.

A method of retrofitting a refrigeration or air conditioning system for using a different refrigerant with high gas discharge temperature, the system including a scroll compressor having a discharge line and a suction line, and a condenser, the method comprising the steps of:

• removing a current refrigerant from the refrigeration system;
• providing a temperature sensor for operative association with the compressor for sensing the temperature of the discharge gaseous refrigerant of the compressor;
• providing a fluid line from the condenser for conducting liquid refrigerant to the suction line of the compressor;
• attaching an injection valve to the fluid line for controlling liquid refrigerant fluid flow into the suction line;
• operatively associating a controller with the injection valve to control the amount of liquid refrigerant injected into the suction line based on the temperature of the discharge gaseous refrigerant of the compressor;
• and
• recharging the system with a different refrigerant.

In a refrigeration system including a compressor having a discharge line for discharging gaseous refrigerant from the compressor and a suction line for admitting gaseous refrigerant into the compressor, a condenser having a liquid refrigerant outlet and an evaporator, each connected to the compressor and to each other in a closed loop, a liquid refrigerant injection system for controlling discharge gas temperature, comprising:

• a temperature sensor, an injection valve, an electronic controller and a liquid refrigerant fluid line connecting the outlet of the condenser to the suction line of the compressor;
• said temperature sensor, for sensing and transmitting temperature signals of discharged gaseous refrigerant;
• said controller electronically coupled to said temperature sensor for receiving said transmitted temperature signals, for comparing said transmitted temperature signals to a preselected temperature, and for developing valve actuating signals for actuating said injection valve;
• said injection valve operatively associated with said controller and communicating with said fluid line, said injection valve responsive to said valve actuating signals, for controlling fluid flow into the suction line, said injection valve including an adjustable orifice through which liquid refrigerant is expanded into the suction line, said adjustable orifice provided by one of a plurality of fluid injection pills, each releasably attached downstream to said valve and each with a different aperture size therethrough.