A vacuum solenoid valve is an electrically controlled valve that is installed on a mechanical vacuum pump to prevent the suckback of vacuum oil to the vacuum system.
How does a vacuum solenoid valve work?
The vacuum solenoid valve and the vacuum pump are connected to the same power supply. When the pump is turned ON/OFF, the solenoid valve follows suit. If the pump is stopped or the power supply is accidentally turned off, the valve automatically closes the vacuum system. This prevents vacuum pump oil from being sucked back into the vacuum chamber and polluting the vacuum system.
Installing a vacuum solenoid valve provides extra protection in case an anti-suckback valve is integrated at the inlet of the vacuum pump. This ensures that the vacuum system is protected from contamination by vacuum pump oil.
Working principle of a solenoid valve
A solenoid valve, also known as an electromagnetic valve, features a solenoid, which is an electromagnetic coil with a movable plunger in the center. Driven by AC or DC power, the plunger is lifted or lowered to open or close the valve orifice. The valve is used as a basic component for a system to control fluids, steam or gases automatically and remotely. Vacuum solenoid valves are used for air or non-aggressive gases.
Vacuum solenoid valves are commonly used in HVAC vacuum pumps and industrial vacuum systems. They are also used in industries such as flat panel display, scientific equipment, semiconductor, industrial degassing, vacuum infusion, and distillation.
Difference between vacuum solenoid valve and ordinary solenoid valve
- Vacuum solenoid valves are direct-acting or assisted lift solenoid valves, while ordinary solenoid valves are generally pilot operated and require pressure differential.
- Vacuum solenoid valves cannot use gap seal due to their high leakage requirement. NBR, PTFE or FKM seals are commonly used.
- The airflow sequence is different because the vacuum causes backflow.
- Vacuum solenoid valves are generally made of stainless steel, while ordinary solenoid valves are available in cast iron, cast steel and stainless steel.