The Overview of Sanitary Diaphragm Valve

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Sanitary diaphragm valve is a special type of shut-off valve. Its opening and closing member is a piece of diaphragm made of soft material, separating the inner chamber of the valve body and inner chamber of the valve cover and actuating components, hence the name diaphragm valve.

The features of diaphragm valve are as follows, with the most prominent being that the diaphragm separates the inner chamber of lower part valve body from the inner chamber of upper part valve cover, so that the valve stem and valve flap over the diaphragm will not be corroded by media, eliminating the stuffing sealing structure, with no external leakage of the medium.

1. Diaphragm that is made of soft sealing such as rubber or plastics has good sealing performance. As diaphragm is a damageable part, it should be regularly replaced depending on the medium characteristics.
2. Due to limitations of diaphragm materials, diaphragm valve is suitable for occasions where the pressure is low and the temperature is relatively not high.
3. According to structural form, diaphragm valve can be divided into house-type diaphragm valve, DC diaphragm valve, shut-off diaphragm valve, straight-through diaphragm valve, gate plate diaphragm valve and right-angle diaphragm valve. The connection type is usually flange connection. According to actuating method, it can be divided into manual, electric and pneumatic types, of which pneumatic actuation can be divided into always-open, always-closed and reciprocating types.

Sanitary diaphragm valve uses valve stem to press the elastic film tight against the valve seat to block the gas path. Turning the hand-wheel can drive the valve stem to move up and down. When the diaphragm leaves the valve seat, the valve is opened. When the diaphragm is tightly pressed against the valve seat, the valve is closed. If the valve uses nitrile butadiene rubber diaphragm, it is suitable for pre-pumping pipelines and non-corrosive gases whose temperature is -25~80 degrees Celsius. If the valve uses fluorine rubber diaphragm, it can be used in high vacuum system whose operating temperature range is -30~150 degrees Celsius.

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