What Is a Vacuum Gate Valve?
A vacuum gate valve is a valve element that separates two or more vacuum chambers or the vacuum chamber and the atmospheric environment. They are mainly found in vacuum facilities and semiconductor manufacturing facilities. There are various types of gate valves, such as open/close types, open/close motors, and valve plug structures.
The selection is based on factors such as the pressure difference across the valve plug, the opening/closing speed, the level of dust and dirt generated during opening and closing, heat resistance, chemical resistance, and so on. From small-sized products with a few tens of millimeters in diameter to flat panel display production equipment to large valves several meters wide.
Uses of Vacuum Gate Valves
Vacuum gate valves are used to separate multiple vacuum chambers or to partition a vacuum chamber from the atmosphere. In this case, the vacuum gate valves are used for transferring materials to another vacuum chamber while maintaining a vacuum in one vacuum chamber at all times.
In this case, the vacuum chamber is always kept in a vacuum state while the materials to be processed are transferred to the other vacuum chamber, and the vacuum chamber is partitioned from the atmosphere. The valve is also used to control the flow rate of the gas exhausted from the vacuum chamber by adjusting the valve opening rate.
When used as a flow control valve, a butterfly type valve with a fast opening/closing speed is used.
Principle of Vacuum Gate Valves
There are many variations of the vacuum gate valve, depending on the valve plug and the open/close structure.
The valve plug has an airtight vacuum chamber. The valve plug is equipped with an O-ring and sealing material to maintain the airtightness of the vacuum chamber, and some products have a built-in heater to maintain the same temperature as the vacuum chamber, which is controlled at high temperatures.
- Elevating Gate Valve
This is the most common type of gate valve, which opens and closes by moving the valve plug up and down. Smaller types are made airtight by a single action of ascending, while larger types often require two actions of ascending and then pressing down.
Since both sides of the valve plug create a vacuum, the housing also has an O-ring or other sealed structure. Valve plugs are available in square and round shapes. - Door Valve
The valve that separates the atmosphere side and the vacuum chamber is called a door valve. It is similar to a lift gate valve, but since one side is at atmospheric pressure, it does not have a housing, and the valve disc is pressed against the vacuum chamber to make it airtight. - Pendulum Type Gate Valve
This type of valve has a round valve plug, which opens and closes by moving like a pendulum. It is characterized by its compactness and has the advantage of low dust emission due to the small number of sliding parts.