Lianke Valve Co., Ltd. specializes in the production of fluorine-lined diaphragm valves, which are used in the petrochemical industry and can withstand corrosive media such as strong acid and alkali organic solvents. The type of fluorine-lined diaphragm valve in the video is weir type, the body material is carbon steel, the lining material is FEP, and the double-layer diaphragm FEP+EPDM can effectively prevent sealing leaks and other problems, which is the first choice in the chemical industry. Lianke products are worth having!The structure of the diaphragm valve is very different from the general valve, is a new type of valve, is a special form of truncation valve, its opening and closing parts is a diaphragm made of soft material, the valve body cavity and the valve cover cavity and drive parts are widely used in various fields. Commonly used diaphragm valves are rubber lined diaphragm valves, fluorine lined diaphragm valves, unlined diaphragm valves, plastic diaphragm valves. The diaphragm valve is equipped with a flexible diaphragm or combined diaphragm in the valve body and the valve cover, and the closing part is a compression device connected with the diaphragm. The seat can be weir shaped, or it can be the wall of the straight flow channel. The advantage of diaphragm valve is that its control mechanism is separated from the medium path, 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 control mechanism. In addition, no separate seal of any kind is required at the stem, except for use as a safety feature in the control of hazardous media. In the diaphragm valve, because the working medium is only in contact with the diaphragm and the valve body, both of which can use a variety of different materials, the valve can ideally control a variety of working media, especially suitable for media with chemical corrosion or suspended particles. The operating temperature of the diaphragm valve is usually limited by the material used in the diaphragm and valve body lining, and its operating temperature range is about -50 to 175 ° C. Diaphragm valve structure is simple, only by the valve body, diaphragm and valve head assembly of three main components. The valve is easy to remove and service quickly, and the diaphragm can be replaced on-site and in a short time.The diaphragm valve replaces the spool assembly with a corrosion-resistant lined body and a corrosion-resistant diaphragm, which uses the movement of the diaphragm to regulate. The valve body material of the diaphragm valve is cast iron, cast steel, or cast stainless steel, and is lined with a variety of corrosion-resistant or wear-resistant materials, diaphragm material rubber and polytetrafluoroethylene. The diaphragm of the lining has strong corrosion resistance and is suitable for the regulation of strong corrosive media such as strong acid and alkali. The diaphragm valve has the advantages of simple structure, small fluid resistance and large flow capacity compared with other types of valves of the same specifications. No leakage, can be used for the adjustment of high viscosity and suspended particles medium. The diaphragm isolates the medium from the upper chamber of the valve stem, so the medium will not leak out without packing. However, due to the limitations of the diaphragm and lining materials, the pressure resistance and temperature resistance are poor, and are generally only suitable for 1.6MPa nominal pressure and below 150 ° C.The flow characteristic of diaphragm valve is close to the fast opening characteristic, and it is approximately linear before 60% stroke, and the flow rate after 60% does not change much. Pneumatic diaphragm valves can also be equipped with feedback signals, limiter and positioner devices to meet the needs of automatic control, program control or flow regulation. The feedback signal of pneumatic diaphragm valve adopts contactless sensing technology. The product uses a thin film propulsion cylinder instead of the piston cylinder, eliminating the piston ring is easy to damage, resulting in leakage and resulting in the failure to push the valve opening and closing. When the air source fails, the handwheel can be operated to open and close the valve.The sealing principle of the diaphragm valve depends on the downward movement of the operating mechanism to press the diaphragm or the diaphragm assembly and the channel of the weir lining valve body or the straight lining valve body, so that the seal is achieved. The specific pressure of the seal is realized by the downward pressure of the closing part. Because the valve body can be lined with a variety of soft materials, such as rubber or polytetrafluoroethylene; The diaphragm is also made of soft materials, such as rubber or polytetrafluoroethylene lined with synthetic rubber, so it can be completely sealed with a small sealing force. [2]Diaphragm valves have only three main components: body, diaphragm and bonnet assembly. The diaphragm separates the inner cavity of the lower valve body from the inner cavity of the upper valve cover, so that the valve stem, valve stem nut, valve disc, pneumatic control mechanism, electric control mechanism and other parts located above the diaphragm do not contact with the medium, and will not produce media leakage, eliminating the sealing structure of the stuffing box.Diaphragm valve is a special form of cut-off valve, the opening and closing part is a diaphragm made of soft material, which separates the valve body cavity from the valve cover cavity. Due to the limitations of the valve body lining process and the diaphragm manufacturing process, the larger valve body lining and the larger diaphragm manufacturing process are difficult, so the diaphragm valve should not be used for larger pipe diameters, generally used in pipelines below DN300. Due to the limitation of diaphragm material, diaphragm valves are suitable for low pressure and low temperature occasions. Generally do not exceed 180℃. Because the diaphragm valve has good anti-corrosion performance, it is generally used for corrosive media devices and pipelines. Due to the temperature of the diaphragm valve, the applicable medium is limited by the lining material of the diaphragm valve body and the diaphragm material.The feature of the diaphragm valve as below:(1) Low fluid resistance.(2) can be used for media containing hard suspended matter; Because the medium is only in contact with the valve body and diaphragm, there is no need for stuffing box, there is no stuffing box leakage problem, and there is no corrosion possibility for the valve stem part.(3) Suitable for corrosive, viscous, slurry media.(4) Can not be used for high pressure occasions.
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