Diaphragm valve is a shut-off valve that uses a diaphragm as an opening and closing part to close the flow channel, cut off the fluid, and separate the inner cavity of the valve body from the inner cavity of the valve cover. The diaphragm is usually made of rubber, plastic and other elastic, corrosion-resistant, and non-permeable materials. The valve body is mostly made of plastic, glass fiber reinforced plastic, ceramic or metal rubber-lined materials. Simple structure, good sealing and anti-corrosion performance, and low fluid resistance. It is used for media with low pressure, low temperature, strong corrosiveness and suspended matter. According to the structure, there are roof type, cut-off type, gate type and so on. According to the driving mode, it is divided into manual, pneumatic and electric.
Diaphragm valve
Working characteristics of diaphragm valve
1. Simple structure and few parts. Diaphragm valve is only composed of three main parts: valve body, diaphragm and bonnet assembly.
2. Convenient disassembly and maintenance. Under normal circumstances, 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. You only need to remove the valve cover. The replacement of the diaphragm can be completed in a short time on site.
3. Good sealing performance Since the diaphragm is made of soft materials such as rubber or plastic, it has better sealing performance, but the mechanical life of the diaphragm is shorter. The medium in the valve will not leak from the connection between the valve body and the valve cover. 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 path of the valve body is streamlined, the flow path is smooth, and there is no dead angle. The medium flowing through the valve cannot be deposited in the valve to become moldy and deteriorate, and it is easy to wash. Stuck.
5. Diaphragm valves with no packing structure do not need packing, and are 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 the lining, it has good chemical resistance.
8. Suitable for various working conditions. Diaphragm valves are especially suitable for dangerous chemicals and radioactive fluids. Because the valve does not produce pollution, it is widely used in product processing, pharmacy, food, nuclear industry and other industries that do not allow pollution.
Basic principle of diaphragm valve
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, it adjusts the flow through the valve to achieve the purpose of adjustment; when the diaphragm covers the weir surface of the valve body, the passage is cut off. The flow rate of the valve, the valve is closed.