Solenoid valves
A solenoid valve is an electrically controlled valve with a fast response time and low power consumption that can be used effectively in multiple areas of an HVAC and refrigeration system. The Solenoid valves play an important role in refrigeration and air conditioning systems by controlling the flow of refrigerants. The base function of these valves is to turn the refrigerant flow on and off and thus ensure system performance. Solenoid valves are available in a wide range of outputs, operating pressures/temperatures, connections, couplings, and with various coil types, with a variety of outputs and using the most common voltages.
Solenoid valves are typically classified in two types according to the stem and plunger action; Direct action and Pilot operated.
Direct action or Direct actuated solenoid valve
In this type of solenoid valves, energizing the coil directly opens the main port of the valve and allowing full flow. A direct acting valve pulls the plunger against inlet pressure and is typically limited to small applications or where there is a low-pressure differential across the valve.
Pilot operated or Servo actuated solenoid valve
In this operation type, energizing the coil opens a pilot port which releases pressure above the main piston or diaphragm and allowing it to move to an open position for full flow. A pilot-operated valve makes use of a pressure differential across the valve to allow for higher flow capacities without the need for a large solenoid coil. Minimum pressure difference required is 1 psi to allow the instrument to return to its normal position.
In connection port, there are two type of Solenoid valves; 2-way and 3-way solenoid valves.
2-way solenoid valve
Two-way valves are shut-off valves with one inlet port and one outlet port. This type of valve is very common in refrigeration and air conditioning systems and is installed in required places.
3-way solenoid valve
3-way valves have three port connections and two valve seats. One valve seal always remains open and the other closed in the de-energized mode. 3-way solenoid valve usually used in some application like heat reclaim.
