What is the difference between ball valve and diaphragm valve？

Ball valve is evolved from plug valve. From following feature of these two kinds of valve,we will conclude the difference between ball valve and diaphragm valve.

List of content for this article：

l  Main features of the ball valve:

l  Diaphragm valve features:

Main features of the ball valve:                

The ratio of the ball's surface to the passage opening should be such that when the ball is rotated 90°, the spherical surface should be entirely present at the inlet and outlet to intercept the flow.

The ball valve only needs to be rotated 90° and a small turning torque to close tightly. The fully equal valve body cavity provides a small, straight-through flow path for the medium. Ball valves are generally considered to be the most suitable for opening and closing, but recent developments have designed ball valves to throttling and control flow. The main features of the ball valve are its compact structure, easy operation and maintenance, suitable for general working media such as water, solvent, acid and natural gas, and also suitable for medium with harsh working conditions such as oxygen, hydrogen peroxide, methane and ethylene. The ball valve body may be integral or combined.

The utility model has the advantages of compact structure, reliable sealing, simple structure and convenient maintenance,the sealing surface and the ball surface are often closed, and is not easily eroded by the medium, and is easy to operate and maintain. It is suitable for general working media such as water, solvent, acid and natural gas, and is also applicable. Mediums with harsh working conditions, such as oxygen, hydrogen peroxide, methane and ethylene, are widely used in various industries. The ball valve body may be integral or combined.

Diaphragm valve features:

Diaphragm valves are a special form of globe valve that appeared in the 1920s. Its opening and closing part is a diaphragm made of soft material, which separates the valve body cavity from the bonnet inner cavity and the driving component, so it is called a diaphragm valve.

The most prominent feature is that the diaphragm separates the lower valve body cavity from the inner cavity of the upper valve cover, so that the valve stem, valve disc and other parts located above the diaphragm are not corroded by the medium, the packing sealing structure is omitted, and no leakage of the medium occurs.

1. The diaphragm made of soft seal such as rubber or plastic has good sealing performance. Since the diaphragm is a consumable part, it should be replaced periodically depending on the characteristics of the medium.

2. Limited by the diaphragm material, the diaphragm valve is suitable for low pressure and relatively low temperature.

3. Diaphragm valves can be divided into six types according to the structure: house type, direct current type, cut-off type, straight-through type, gate type and right angle type; the connection form is usually flange connection; according to the driving method, it can be divided into manual, electric and pneumatic. Three kinds, among which the pneumatic drive is divided into three types: normally open, normally closed and reciprocating.

4. Generally not suitable for use in pipelines with temperatures above 60 °C and transporting organic solvents and strong oxidizing media, and should not be used in pipelines with higher pressure.

Ball valve has the same 90° lift action, except that the plug body is a ball with a circular through hole or passage through its axis. 

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