The difference between imported vacuum butterfly valve and ordinary butterfly valve

Butterfly valve is a type of common valve, if the butterfly valve is divided into types according to the pressure used, the common imported butterfly valve is divided into imported vacuum butterfly valve and ordinary butterfly valve. Now analyze the difference between vacuum butterfly valve and ordinary butterfly valve

1. Differences in definition
Vacuum butterfly valve refers to the butterfly valve in a vacuum state inside the valve, which is called negative pressure in the industry. The pressure in the valve cavity is lower than the atmospheric pressure, and it is often used in vacuum piping systems as a device to unblock and cut off the flow of media.
Ordinary butterfly valve refers to the butterfly valve used in positive pressure occasions, which cannot be used in a vacuum environment, because the ordinary butterfly valve does not have the ability to resist negative pressure, and placing it in a vacuum environment will affect its performance. Ordinary butterfly valves are usually used in environments greater than or equal to atmospheric pressure. The performance of butterfly valves in different environments is different.

2. The working principle is different
The working principle of the vacuum butterfly valve is to realize the opening and closing of the valve by rotating the butterfly plate fixed on the rotating shaft by 90°. Compared with other vacuum valves of the same caliber, the vacuum butterfly valve has the advantages of simple structure, large conduction capacity, short length of valve body structure, and fast opening and closing speed.
Ordinary butterfly valve is a kind of valve that opens and closes according to the rotating valve stem at the same time to drive the disc plate to rotate, in the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, mainly the rotating disc plate 90 ° to do flow control, when the disc plate reaches 90 °, the valve is in a fully open state, and the angle of the disc plate can be changed to adjust the medium flow rate, which is generally installed in the diameter direction of the pipeline. The butterfly valve and the valve stem itself have no locking ability, in order to effectively regulate the flow rate, the worm gear reducer needs to be installed, and the butterfly valve with worm gear reducer not only makes the butterfly valve have the ability to lock itself, but also can change the operating performance of the butterfly valve and adjust the medium flow more accurately.

3. The medium used is different
Vacuum butterfly valves are usually used in vacuum pipes for steam or water. There are certain differences in the environment and scope of use between the two. The most common butterfly valve for vacuum environment is in the negative pressure system, which can achieve vacuum isolation and sealing to avoid leakage.
The medium used in ordinary butterfly valves is generally water, positive pressure gas, oil, and some corrosive media, cement or valves in the applicable field and petroleum industry.

The use pressure is different
Ordinary butterfly valve generally refers to the pressure used for positive pressure, but the high pressure can be used to about 6.4Mpa, and cannot be used for vacuum negative pressure.
The vacuum butterfly valve cannot be used for high pressure, but can be used for vacuum negative pressure occasions. His track record covers most of the vacuum environments, such as:
1) Low vacuum valve: medium pressure p=760~1 mm Hg; 2) Medium vacuum valve: p = 1×10-3 mm Hg. 3) High vacuum valve: p=1×10-4~1×10-7 mm Hg; 4) Ultra-high vacuum valve: p≤1×10-8 mm Hg. Vacuum valves are widely used as linear motion vacuum bellows globe valves with valve stems.

5. The connection mode is different
   The connection methods of ordinary butterfly valves generally include conventional flanges, welding, and clamp types; The connection mode of the vacuum butterfly valve is the quick-release flange, and the looper flange is the main one.