What is the Ball Valve Used for?
The ball valve is mainly used to cut off, distribute and change the flow direction of the medium in the pipeline. It only needs to be rotated 90 degrees and a small torque can be closed tightly. Ball valves are most suitable for switching and shut-off valves.
Since the ball valve usually uses rubber, nylon and polytetrafluoroethylene as the material of the seat seal, its operating temperature is limited by the material of the seat seal. The cut-off function of the ball valve is accomplished by pressing the metal ball against the plastic valve seat under the action of the medium (floating ball valve). Under the action of a certain contact pressure, the valve seat sealing ring undergoes elastic-plastic deformation in local areas. This deformation can compensate the manufacturing accuracy and surface roughness of the ball, and ensure the sealing performance of the ball valve.
The valve seat sealing ring of the ball valve is usually made of plastic, so when choosing the structure and performance of the ball valve, the fire resistance and fire resistance of the ball valve should be considered, especially in the petroleum, chemical, metallurgical and other departments. In the equipment of flammable and explosive media When the ball valve is used in the pipeline system, more attention should be paid to fire resistance and fire protection.
The many unique characteristics of ball valves determine that the use of them is relatively wide. Usually, in two-position adjustment, strict sealing performance, mud, wear, shrinking channels, rapid opening and closing actions (1/4 turn opening and closing), high pressure cut-off ( Ball valves are recommended for pipeline systems with large pressure difference), low noise, cavitation and gasification, a small amount of leakage to the atmosphere, small operating torque, and small fluid resistance.
The ball valve is also suitable for the pipeline system of light structure, low pressure cut-off (small pressure difference) and corrosive medium. Ball valves can also be used in cryogenic (cryogenic) installations and piping systems. In the oxygen pipeline system in the metallurgical industry, ball valves that have undergone strict degreasing treatment are required. When the main line in the oil pipeline and the gas pipeline needs to be buried underground, a full-bore welded ball valve should be used. When the adjustment performance is required, a ball valve with a special structure with a V-shaped opening should be selected. In petroleum, petrochemical, chemical, electric power, and urban construction, metal-to-metal sealing ball valves can be selected for pipeline systems with a working temperature above 200℃.
How to choose a right ball valve?
- The pipelines and storage equipment of refined oil use flanged ball valves.
- On the pipeline of city gas and natural gas, the floating ball valve with flange connection and internal thread connection should be selected.
- In the oxygen pipeline system, it is advisable to use a fixed ball valve that has undergone strict degreasing treatment and is flanged.
- In the pipeline system and device of low temperature medium, the low temperature ball valve with valve cover should be selected.
- On the pipeline system of the catalytic cracking unit of the oil refining unit, the lifting rod type ball valve can be selected.
- In the devices and pipeline systems of corrosive media such as acid and alkali in chemical systems, all stainless steel ball valves made of austenitic stainless steel and PTFE as the valve seat sealing ring should be selected.
- Metal sealing ball valves can be used in pipeline systems or devices of high temperature medium in metallurgical systems, power systems, petrochemical plants, and urban heating systems.
- When flow adjustment is required, a pneumatic ball valve or electric ball valve with V-shaped opening can be selected.