The structure of the diaphragm valve is very different from the general valve. It is a new type of valve. It is a special form of truncation valve. Its opening and closing parts is a piece of diaphragm made of soft material. The valve body cavity and the valve cover cavity and driving parts separated. It is widely use in various fields. Commonly used diaphragm valves are rubber lined diaphragm valve, fluorine lined diaphragm valve, unlined diaphragm valve, plastic diaphragm valve.
The diaphragm valve replaces the spool assembly with a corrosion-resistant lined body and a corrosion-resistant diaphragm, which uses the diaphragm’s movement for adjustment. Diaphragm valve body material using cast iron, cast steel, or cast stainless steel, and lined with a variety of corrosion resistant or wear-resistant materials, diaphragm material rubber and ptfe. The diaphragm lining has strong corrosion resistance, suitable for the adjustment of strong acid, alkali and other corrosive media.
The structure of diaphragm valve is simple. Fluid resistance is smal. Flow capacity is larger than other types of valves with the same specifications. No leakage, can use for high viscosity and suspended particle medium adjustment. The diaphragm isolates the media from the stem cavity, so no packing media will leak out. However, due to the limitations of diaphragm and lining materials. The pressure resistance and temperature resistance are poor, generally only applicable to 1.6MPa nominal pressure and 150℃ below.
The flow characteristics of the diaphragm valve are close to the fast opening characteristics, approximately linear before 60% of the stroke, and the flow changes little after 60%. Pneumatic diaphragm valve can attach with feedback signal, limit and positioner and other devices, to adapt to the needs of automatic control, program control or flow regulation. Pneumatic diaphragm valve feedback signal using contactless sensing technology. The product uses a thin-film propulsion cylinder to replace the piston cylinder, eliminating the disadvantages of easy damage to the piston ring, resulting in leakage and unable to promote the valve opening and closing. When the gas source fails, you can operate the handwheel to open and close the valve.