A vacuum ball valve refers to a ball valve that operates at a pressure lower than standard atmospheric pressure, creating a certain degree of vacuum.

Below, the editor will briefly introduce several connection forms and characteristics of vacuum ball valves, as follows:

threaded connection

This is a simple connection method commonly used for small valves. There are two situations:

1) Indirect sealing: The force of tightening the thread is transmitted to the gasket between two planes, allowing the gasket to provide a sealing effect.

2) Direct sealing: The internal and external threads provide a direct sealing effect. To ensure that there is no leakage at the connection, lead oil, hemp, and polytetrafluoroethylene tape are often used for filling; Among them, polytetrafluoroethylene raw material tape is becoming increasingly widely used; This material has good corrosion resistance, excellent sealing effect, and is easy to use and store. When disassembling, it can be completely removed because it is a non stick thin film, much more than lead oil and hemp.

flange connection

This is the most commonly used connection form in valves. According to the shape of the joint surface, it can be divided into the following types:

1) Trapezoidal groove type: using elliptical metal rings as gaskets, used for valves with working pressure ≥ 64 kg/cm2 or high-temperature valves.

2) O-ring type: This is a relatively new form of flange connection that has developed with the emergence of various rubber O-rings. It is more reliable in terms of sealing effect than general flat washers.

3) Mortise and tenon type: It can use gaskets with large plastic deformation, which are widely used in corrosive media and have good sealing effect.

4) Concave convex type: With high working pressure, medium hard gaskets can be used.

5) Lens type: The gasket is in the shape of a lens and made of metal. Used for high-pressure valves or high-temperature valves with a working pressure of ≥ 100 kg/cm2.

6) Smooth type: Used for valves with low pressure. Processing is relatively convenient.