Diaphragm valve is a stop valve that uses diaphragm as the opening and closing part to close the flow channel, block the fluid, and separate the inner cavity of valve body and bonnet. Diaphragms are usually made of elastic, corrosion-resistant and impermeable materials such as rubber and plastic. The valve body is mostly made of plastic, FRP, ceramic or metal rubber lining materials. Simple structure, good sealing and anti-corrosion performance, and low fluid resistance. It is used for medium with low pressure, low temperature, strong corrosivity and suspended substances. According to the structural form, it can be divided into ridge type, cut-off type, ram type, etc. According to the driving mode, there are manual, pneumatic and electric.
1. With simple structure and few parts, the diaphragm valve is only composed of three main parts: valve body, diaphragm and bonnet assembly.
2. Easy disassembly and maintenance. Generally, the damaged part of the diaphragm valve is the diaphragm. When replacing the diaphragm, you don't need to remove the valve from the pipeline, just remove the valve cover, and the replacement of the diaphragm can be completed in a short time on site.
3. Good sealing performance. 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 connection of 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 channel of the valve body is streamlined, smooth and free of dead angle. The medium flowing through the valve cannot deposit in the valve and become moldy and deteriorated, and it is easy to wash. The medium flowing through, such as fiber or particles, will not get stuck.
5. The diaphragm valve without packing structure does not need packing, which is non corrosive to the valve stem and bonnet (because the diaphragm separates the lower valve body from the inner cavity of the upper bonnet).
6. It can be used for cutting off and throttling.
7. Corrosion resistance due to the diversity of lining, it has good chemical resistance.
8. The diaphragm valve is suitable for various working conditions, especially for dangerous 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 that do not allow pollution.
There is a diaphragm between the valve body and the valve cover 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 regulation; When the diaphragm covers the weir surface of the valve body, the flow through the valve is cut off and the valve is closed