Electrically operated shut-off valves (Figure 9.6) are required for refrigerant and other circuits. These take the form of a plunger operated by a solenoid and working directly on the valve orifice or through a servo. The usual arrangement is to energize the solenoid to open the valve and de-energize to close. Sizes up to 50 mm bore tube connections are made. Beyond this, the solenoid acts as a pilot to a main servo (see Figure 9.7).
Solenoid valves are used in refrigeration and air-conditioning systems for refrigerant lines, oil pressure pipes (to control oil return and capacity reducers), and water and compressed air lines.
Valve seat Mounting hole
Armature Valve plate
Figure 9.6 Solenoid valve (Danfoss)
Figure 9.7 Evaporator pressure regulator valve (Danfoss)
Posted in Refrigeration and Air Conditioning