The structure of diaphragm valve is very different from that of general valves. It relies on soft rubber film or plastic film to control fluid movement. The commonly used diaphragm valve materials are divided into cast iron diaphragm valve, cast steel diaphragm valve, stainless steel diaphragm valve and plastic diaphragm valve.

Working principle of diaphragm valve

A diaphragm is arranged between the valve body and the bonnet of the diaphragm valve. The diaphragm is made of rubber or polytetrafluoroethylene. When the diaphragm moves up and down, the flow through the valve is adjusted to achieve the purpose of adjustment: when the diaphragm covers the weir surface of the valve body, the flow through the valve is cut off and the valve is closed.

Advantages of diaphragm valve

1. The diaphragm valve has simple structure and few parts. The diaphragm valve is composed of only three main single parts: valve body, diaphragm and bonnet assembly.

2. It is easy to disassemble and maintain. Generally, the damaged part of the diaphragm valve is the diaphragm. When replacing the diaphragm, you do not need to remove the valve from the pipeline, just remove the valve cover. The replacement of the diaphragm can be completed in a short time on site.

3. The sealing performance is good. Because the diaphragm is made of soft materials such as rubber or plastic, it has good sealing performance, but the mechanical life of the diaphragm is short. The medium in the valve will not leak from the joint of the valve body and bonnet. The upstream and downstream of the valve can be completely cut off without internal leakage.

4. There is no dead angle in the valve. The flow passage of the valve body is streamlined, smooth, and free of dead angles. The medium flowing through the valve cannot deposit in the valve and become moldy and deteriorated, and it is convenient for flushing. The medium flowing through the valve, such as containing fibers or particles, will not be stuck.

5. The diaphragm valve without packing structure does not need packing and has no corrosivity to the valve stem and bonnet (because the diaphragm separates the lower valve body from the upper bonnet cavity).

6. It can be widely used for cutting off and throttling.

7. Corrosion resistance Because of the diversity of lining, it has good chemical resistance.

8. The diaphragm valve is suitable for various working conditions, especially for hazardous chemicals and radioactive fluids. Because the valve will not produce pollution, it is widely used in product processing, pharmaceutical, food, nuclear industry and other industries where pollution is not allowed.

Type of diaphragm valve

EG41W British standard diaphragm valve, G41W/J/FS rubber lined diaphragm valve/fluorine lined diaphragm valve, G45J DC rubber lined diaphragm valve, EG6K41W/J/FS British standard pneumatic diaphragm valve, British standard pneumatic rubber lined diaphragm valve (reciprocating), G6B/K41J national standard pneumatic fluorine lined diaphragm valve, G641W/J/Fs reciprocating pneumatic diaphragm valve, G941W/J/Fs electric diaphragm valve, GM vacuum diaphragm valve, EG11W/J internal thread diaphragm valve, SEG41W sanitary stainless steel diaphragm valve, G49W three-way diaphragm valve J45J/Fs DC rubber lined stop valve, G41F plastic diaphragm valve.

Development direction of diaphragm valve

At present, there are two major development directions for diaphragm valve production abroad. One is large-scale and high parameter, mainly to meet various special requirements and reflect the design and manufacturing level of various countries. If the nominal pressure can reach PN16~40, the maximum pressure level can reach 4.5MPa, and the working temperature can reach; 65~200 ° C, the maximum temperature can reach 300 ° C. In addition to meeting the water treatment system of 300MW, 600MW and 1500MW large thermal power generating units, diaphragm valves are also used in 900MW nuclear power plants. Second, it can meet the supporting needs of general industrial pipelines. It can produce a large number of products in a wide range to adapt to a variety of corrosive media, which is suitable for nearly 400~700 kinds of media. The service life of rubber diaphragm valve reaches more than 100000 times, and the maximum service life can reach 270000~500000 times. The manufacturer has made great efforts to specialization, automation and standardization by improving process manufacturing, saving raw materials and improving production capacity.