The diaphragm valve is a special form of shut-off valve, which appeared in 1920s. The opening and closing parts of the utility model are diaphragms which are made of soft material, and the inner cavity of the valve body is separated from the inner cavity of the valve cover and the driving component.
The most prominent characteristic of the diaphragm is the lower body cavity and the upper chamber separated from the valve cover, so that the diaphragm is located above the valve stem, valve and other parts from corrosion, eliminating the need for packing structure, and no media leaks.
1, the rubber or plastic soft seal is made of diaphragm with good sealing. Because the diaphragm is a wearing part, it shall be replaced periodically depending on the characteristics of the medium.
2, by diaphragm material limit, diaphragm valve applies to low pressure and temperature is relatively high occasions.
3, diaphragm valve structure can be divided into: house type diaphragm valve, sanitary diaphragm valve, DC cut-off valve, gate valve, straight through diaphragm valve and rectangular diaphragm valve six connected; usually in the form of flange connection; the drive can be divided into manual, electric and pneumatic three. The pneumatic drive is divided into normally opened and normally closed diaphragm valve and reciprocating diaphragm valve.
Diaphragm valve is to use the stem of the elastomer film tight pressure on the valve seat, used to cut off the gas path. By rotating handwheel, we can drive the valve stem up and down, so that the diaphragm leaves the valve seat, open the valve, or make the diaphragm tight on the valve seat, close the valve. Such valves and NBR diaphragm, are applicable to pre – pumping pipe, the temperature is -25 ~ 80 degrees of non corrosive gases. Such as the fluorine rubber diaphragm, can be used in high vacuum system, the use of temperature range is-30 ~ 150 degrees.