he 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, with stem body 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. 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 6.4 MPA, the highest temperature reaches 325