Plug means closing member (stopper) rotating around the center line of the body to achieve the open and close a valve.

Plug in the pipeline is mainly used as cutting, distribution and changing the flow direction of medium. Stopcock is the earliest history been used valves. As a simple structure, opening and closing rapidly (plug a quarter turn to complete opening and closing movements), easy operation, fluid resistance, is still widely used. Currently used mainly for low-voltage, small-caliber and medium temperature is not high in the case. Stopcock plug and plug body is a good fit cone, which taper generally 1:6 and 1:7.

1.Adapter plug valves

Adapter plug valves are usually used for low pressure through pipes, sealing plug and the plug body depends entirely on the degree of matching between the good and bad, which is to rely on the sealing surface of the clamping tighten the nut to achieve lower. Generally used for PN ≤ 0.6Mpa. Shown in Figure .

2.Filler plug valves

Filler plug valves is achieved through compression packing sealing plug and the plug body. As a filler, so good sealing performance. This gland is usually a plug, the plug without outstretched body, thus reducing a leakage of working fluid pathway. This plug is used extensively for PN ≤ 1Mpa pressure, shown in Figure.

3.Self-sealing plug

Self-sealing plug valve pressure through the media itself to achieve between the plug and the plug body pressed sealed. Small head upwardly projecting stopper body, the medium passes through the inlet holes into the bulk of the stopper, the stopper pressed upwards, such a structure is generally used for the air medium,shown in Figure .

4.Seal plug valves

In recent years, expanding the scope of application plug, appeared with forced lubrication oil seal plug valves. Because the plug and forced lubrication plug body formed between the sealing surface of a layer of film. So that better sealing performance, opening and closing effort to prevent damage to the sealing faces.

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