Diaphragm valve overview

Diaphragm valve is a special form of shut-off valve that appeared in the 1920s. Its opening and closing member is a diaphragm made of soft material, which separates the valve body cavity from the bonnet inner cavity and the driving component, so it is called a diaphragm valve. The characteristics of the diaphragm valve are as follows: The outstanding feature of the Zui is that the diaphragm separates the lower valve body cavity from the inner cavity of the upper valve cover, so that the valve stem, valve disc and the like located above the diaphragm are not corroded by the medium, and the packing sealing structure is omitted, and There will be no leakage of the media. 1. The diaphragm made of soft seal such as rubber or plastic has good sealing performance. Since the diaphragm is a consumable part, it should be replaced periodically depending on the characteristics of the medium. 2, limited by the diaphragm material, the diaphragm valve is suitable for low pressure and relatively low temperature. 3. Diaphragm valves can be divided into six types according to the structure: house diaphragm valve, DC diaphragm valve, cut-off diaphragm valve, straight-through diaphragm valve, ram diaphragm valve and right-angle diaphragm valve; the connection form is usually flange connection. According to the driving method, it can be divided into three types: manual, electric and pneumatic. The pneumatic drive is divided into three types: normally open, normally closed and reciprocating. The diaphragm valve uses a valve stem to press the elastomer film against the valve seat to block the air path. Turning the handwheel can move the valve stem up and down, so that the diaphragm leaves the valve seat to open the valve or press the diaphragm against the valve seat to close the valve. Such a valve, such as a nitrile rubber diaphragm, is suitable for non-corrosive gases on pre-stage and pre-extraction pipes and at temperatures between -25 and 80 °C. If a fluororubber diaphragm is used, it can be used in a high vacuum system with a temperature range of -30 to 150 °C.