What is a diaphragm valve?

As far as I know, the commonly used materials for diaphragm valves are divided into: cast iron, cast steel, stainless steel and plastic. Through these, the diaphragm valve can also be classified as a globe valve, because they all have opening and closing parts, but the opening and closing part of the diaphragm valve is a soft diaphragm. Then let me explain this diaphragm valve in detail. The structure of the diaphragm valve is very different from the general valve. It is a new type of valve. The soft diaphragm separates the inner cavity of the valve body from the inner cavity of the valve cover and the driving parts. It is now widely used in various fields. Commonly used diaphragm valves include rubber-lined diaphragm valves, fluorine-lined diaphragm valves, unlined diaphragm valves, and plastic diaphragm valves. Diaphragm valve is equipped with a flexible diaphragm or combined diaphragm in the valve body and valve cover, and its closing part is a compression device connected with the diaphragm. The valve seat can be in the shape of a weir or the wall of the straight flow channel. The advantage of the diaphragm valve is that its operating mechanism is separated from the medium passage, which not only ensures the purity of the working medium, but also prevents the possibility of the medium in the pipeline impacting the working parts of the operating mechanism. Additionally, no separate seal of any kind is required at the stem, except as a safety feature in the control of hazardous media. In the diaphragm valve, since the working medium is only in contact with the diaphragm and the valve body, both of which can use a variety of different materials, so the valve can ideally control a variety of working media, especially suitable for chemical corrosive or suspended particles. medium. The operating temperature of the diaphragm valve is usually limited by the materials used in the diaphragm and valve body lining, and its operating temperature range is about -50~175℃. The diaphragm valve has a simple structure and is only composed of three main components: the valve body, the diaphragm and the valve head assembly. The valve is easy to disassemble and repair quickly, and the replacement of the diaphragm can be done on site and in a short time. The diaphragm valve replaces the valve core assembly with a corrosion-resistant lined valve body and a corrosion-resistant diaphragm, and uses the movement of the diaphragm to adjust. The body material of the diaphragm valve is cast iron, cast steel, or cast stainless steel, and is lined with various corrosion-resistant or wear-resistant materials, diaphragm material rubber and PTFE. The diaphragm of the lining has strong corrosion resistance and is suitable for the adjustment of strong corrosive media such as strong acid and strong alkali. The diaphragm valve has a simple structure, small fluid resistance, and a larger flow capacity than other types of valves of the same specification; no leakage, and can be used for the adjustment of high viscosity and suspended particle media. The diaphragm isolates the medium from the upper cavity of the valve stem, so there is no leakage of the medium without packing. However, due to the limitation of diaphragm and lining materials, the pressure resistance and temperature resistance are poor, and it is generally only suitable for nominal pressure of 1.6MPa and below 150℃. The flow characteristics of the diaphragm valve are close to the quick-opening characteristics, which are approximately linear before 60% of the stroke, and the flow rate after 60% does not change much. Pneumatic diaphragm valves can also be equipped with feedback signals, limiters and positioners to meet the needs of automatic control, program control or flow regulation. The feedback signal of the pneumatic diaphragm valve adopts contactless sensing technology. This product adopts a film-type propulsion cylinder instead of a piston cylinder, which eliminates the disadvantage that the piston ring is easily damaged and causes leakage, which makes it impossible to push the valve to open and close. When the air source fails, the handwheel can still be operated to open and close the valve. Its own characteristics: small fluid resistance. It can be used for the medium containing hard suspended solids; since the medium only contacts the valve body and the diaphragm, there is no need for a stuffing box, there is no leakage of the stuffing box, and there is no possibility of corrosion to the valve stem part. Suitable for corrosive, viscous and slurry media. Cannot be used in high pressure situations. Structural classification: Diaphragm valves can be divided into six types according to their structural forms: house type, DC type, cut-off type, straight-through type, gate type and right-angle type; the connection form is usually flange connection; according to the driving mode, it can be divided into manual, electric and There are three types of pneumatic drives, among which pneumatic drives are further divided into three types: normally open, normally closed and reciprocating. The above is the introduction of the diaphragm valve. If you have any questions or do not understand the introduction of the diaphragm valve, you are welcome to call Lianke Valve Co., Ltd. for consultation, or you can also consult online. Lianke Valve Co.,Ltd. is a company dedicated to valve innovation and manufacturing, and strives to bring more practical and convenient valves to everyone.
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