Working Principle, Applicable Occasion, And Advantages Of Plug Valve
Working principle
Plug valve plug valve with: the hole as on-off valve. Plug body with stem rotation, to realize on-off movement.ball. The small pack-less cock, also known as "test". Cock of body for cone (have), and the cylinder valve cone hole surface with seal components. Cock is one of the earliest use of valve, simple structure, switch quickly, fluid resistance. Ordinary cock by finishing metal plug and body direct contact between the seal, so poor, open the seal power, easy to wear, often can only be used for low (no more than 1 mpa) and small (less than 100 millimeter). In order to expand the scope of application of plug valve, have developed many new structure. Oil lubrication cock is the most important one (see figure [oil lubrication cock]). Special grease from body top injection valve cone and plug, formed between oil film to minimize torque, improve sealing lifts and service life. It's working pressure can reach 64 mpa, the highest temperature reaches 325 ° c, the biggest diameter can be 600 mm.
Cock channels have various forms. Common straight-through flow is mainly used for truncated. Three and four general cock suitable fluid reversing the cock open-close part is a hole in the cylinder, around the axis of rotation vertical channels, thus achieved the purpose of open channel. Cock mainly for the opening and closing of the medium in pipelines and equipment.
Applicable occasions
Because of the plug valve is closed ChengZhu plug form rotate the valve, the valve by turn 90o fortress of channel and body of the channel, or separate together, so open the valve plug valve is the most suitable and rapid open-close occasions, In addition, due to the cock, its structure characteristics is mainly used for cutting and connect medium and distribution and change the flow direction of medium occasions, But according to applicable properties and the corrosion proof sealing, sometimes also can be applied to throttle situation;
In addition, because sealing plug valve between sports and with wiping the rev. When can completely prevent and flow media contacts, so usually can also be used as the medium with suspended particles, Cock of another important characteristics when it easy to adapt multi-channel structure, so that a valve can get two, three or four different flow, and so can simplify piping design, use a few valve replacement, reduce the dosage of valve and equipment need some connection accessories.
Plug valve is widely used in oil and gas drilling, conveying and refining equipment, Also widely used in petrochemical, chemical, natural gas, liquefied petroleum gas, hvac industry, food industry, pharmaceutical industry and in the system.
Non-lubricated type belt bushing to cock, applied to petrochemical, chemical and other industries, especially in are not allowed to apply to medium lubricant.
Cock has been widely used in petroleum, chemical industry, the liquid gas, food, pharmaceutical, urban construction, etc, and the departments of People's Daily life.
The main advantage:
1, applicable to often open operation, quick and light.
2 and fluid resistance.
3, simple structure, small volume, light weight, easy maintenance.
4, sealed performance is good
5, not by the direction of the flow of medium, can be arbitrary.
6, no vibration, low noise. Cock according to the structure form can be divided into tight formulary cock, cock, packing self-styled type plug valve type oil plug valve type and four. According to the passage, can be divided into the form of three general type, three and four general.
