Diaphragm valve is a flexible diaphragm in the valve body and valve cover, which is sealed by the up and down stroke of diaphragm.
The utility model has the advantages of simple structure, easy to disassemble and maintain quickly; due to its control structure, the jade medium path is separated to ensure the purity of the medium. It is suitable for the medium with chemical corrosivity or suspended particles, and even dangerous medium which is difficult to transport. However, due to the limitation of lining material, the temperature and pressure should not be too high.
Diaphragm valves of classification
Diaphragm valve can be divided into the following types according to the structure:
(1) Ridge type
Also known as flange type, is the most basic one. Its structure. As can be seen from the figure, the valve body is lined. Diaphragm valve body lining is to play its corrosion resistance. In addition to the straight through type, this kind of structure can also be made into right angle type.
(2) Cut off type
The structure and shape of the diaphragm valve are similar to that of the globe valve. The fluid resistance of this type of diaphragm valve is larger than that of the ridge diaphragm valve, but the sealing area is large and the sealing performance is good. It can be used in the pipeline with high vacuum degree.
(3) Ram type
The structure of the valve is similar to that of the gate valve. The flow resistance of the gate type diaphragm valve is the minimum, which is suitable for conveying viscous materials.
Natural rubber, chloroprene rubber, butadiene rubber, isobutylene rubber, fluorinated rubber and fluoroethylene propylene plastic (F46) are commonly used as diaphragm materials.
The disadvantage of diaphragm valve is that the pressure resistance is not high, generally within 6kgf / cm2 (0.6MPa); the temperature resistance is also limited by the diaphragm, generally it can only withstand 60 ~ 80 ℃, and the highest (fluorinated rubber) is not more than 180 ℃.