What kind of valves belong to the diaphragm valve how to choose correctly

- May 01, 2018-

The diaphragm valve belongs to the clamp type valve, it is mainly used for opening and closing in the pipeline. Diaphragm valve has two main advantages one is that the valve does not need a separate valve stem packing seal structure, diaphragm in the cutting media at the same time to the valve stem sealing function. The second is very flexible diaphragm close reliable, to the sewage can do a good cut off.

Therefore, the control mechanism and the media channel are completely separated, so that the diaphragm valve can not only apply to the food industry and medical and health industry, but also for some difficult to transport media and more dangerous media. However, because the diaphragm valve diaphragm must be made of a good elastic non-metallic material, diaphragm valve temperature is usually subject to diaphragm materials and valve body lining material allowable temperature limit.

In addition, as the diaphragm valve in the work of the media on the diaphragm stress, the diaphragm valve life than other valve life is shorter. Usually, the use of conditions or requirements of strict sealing performance, slurry media, wear, light structure, low pressure cut-off (small pressure difference), to the atmosphere a small amount of leakage, abrasive media recommended the selection of diaphragm valve. In the dual-position adjustment, throttling, adjustment, channel necking, low throat sound, cavitation and vaporization phenomenon, small torque control occasions can choose diaphragm valve. In high temperature medium, high pressure medium, high pressure cut-off (big pressure difference), fast opening and closing action, short structure length of the condition as far as possible not to choose diaphragm valve.

Except for metal diaphragm valves. The metal diaphragm valve is characterized by clamping a thin, hemispherical metal film into the valve body as a barrier between the stem and the fluid. The valve is closed by the valve wardrobe and metal film to the disc pressure on the seat to achieve. The valve is opened through an internal spring, and when the stem is raised and detached from the film, the disc rises. Because the stroke of the valve is equal to the film's stroke, the valve is characterized by a much smaller lift than the general valve. In order to overcome the loss of resistance due to low lift, the seat and the circulation area is larger than the normal valve, the purpose is to obtain greater flow. Because the valve seat of this valve is larger, the force is much larger than the usual valve, in order to get enough sealing force on the disc. Because there is no direct contact between the stem and the disc, the disc will not pass through the stem to leave the seat, so this valve is suitable for use in a one-way flow of pressure, and usually media from the "seat below." However, in use should avoid a large number of backflow, so as not to affect the closure of the valve. In general, in high temperature, high pressure selection of metal diaphragm valve when the economy, effective. The valve can also be selected in the use of synthetic rubber diaphragm valve low temperature, low pressure occasions.