Source：Aogong Valve Co. LTDRelease time：2022.08.30Page views：133
Ball valve was born in the 1950s, with the rapid development of science and technology, the continuous improvement of production process and product structure, in a short time of 50 years, has rapidly developed into a major valve class. In western industrially developed countries, the use of ball valves is increasing year by year.
Ball valve in the pipeline is mainly used to cut off, distribution and change the direction of the flow of the medium, it only needs to rotate 90 degrees of operation and a small torque to close tight. Ball valve is most suitable for switch, cut off valve use.
Because ball valves are usually made of rubber, nylon, and teflon seat ring materials, their operating temperature is limited by seat ring materials. The cutoff function of the ball valve depends on the metal ball under the action of the medium, in the plastic seat between each other to complete (floating ball valve). Elastoplastic deformation occurs in local area under certain contact pressure of valve seat seal ring. This deformation can compensate the ball manufacturing precision and surface roughness, to ensure the sealing performance of the ball valve.
And because the valve seat ring is usually made of plastic, so in the selection of the structure and performance of the ball valve, to consider the fire resistance and fire resistance of the ball valve, especially in the petroleum, chemical, metallurgy and other departments, the use of the ball valve in inflammable, explosive medium equipment and piping system, more attention should be paid to fire resistance and fire prevention.
Ball valves include: floating ball valves, fixed ball valves, track ball valves, V-shaped ball valves, three-way ball valves, stainless steel ball valves, floating ball valves, cast steel ball valves, ash discharge ball valves, anti-sulfur ball valves, sleeve ball valves, welding ball valves.
In addition according to the function and transmission form can also be classified as follows：
1.Has the lowest flow resistance (actually zero).
2.It will not get stuck when there is no lubricant, so it can be used reliably with corrosive media and low boiling point liquid.
3.In the range of high earth pressure and temperature, it can achieve 100% sealing.
4.It can realize super fast opening and closing, and the opening and closing time of some structures is only 0.05~0.1s, so as to ensure that it can be used in the automation system of the test bench. Quick open and close the valve, operation without impact.
5.Ball type closing member can be automatically positioned in position.
6.The working medium is reliably sealed on both sides.
7.When fully open and fully closed, the sealing surface of the ball and the seat is isolated from the medium, so the high speed through the medium of the valve will not cause the erosion of the sealing surface.
8.Compact structure and light weight, it can be considered to be suitable for low temperature medium system of the most reasonable valve structure.
9.Body symmetry, especially welded body structure, can well withstand the stress from the pipe.
10.The closing parts can withstand the high pressure difference when closing.
11.All-welded valve valve can be directly buried in the ground, so that the valve internals from erosion, the maximum service life of up to 30 years, is the most ideal valve for oil and gas pipelines.
Many unique characteristics of the ball valve determine the use of the ball valve is relatively wide, usually in the double position adjustment, strict sealing performance, mud, wear, shrinking channel, opening and closing action quickly (1/4 turn to open and close), high pressure cut-off (large pressure difference), low noise, cavitation and gasification phenomenon, a small amount of leakage to the atmosphere, small operating torque, fluid resistance pipeline system, Ball valves are recommended.
Ball valve is also suitable for light structure, low pressure cut-off (small pressure difference), corrosive media piping system. Ball valves can also be used in low temperature (cryogenic) devices and piping systems. Strictly degreased ball valves are used in oxygen piping systems in the metallurgical industry. Full-diameter welded ball valves are used when the main lines of oil and gas pipelines are buried underground. When required to have regulating performance, the ball valve with a special structure of V-shaped opening should be selected. In petroleum, petrochemical, chemical, electric power, urban construction, the working temperature of more than 200 degrees of piping system can be selected metal-to-metal sealed ball valve.
The main pipeline of oil and natural gas transmission, the need to clean the pipeline, and buried in the ground, the selection of all-pass, all-welded ball valve structure; Buried on the ground, choose all through the welding connection or flange connection ball valve; Branch pipe, flange connection, welding connection, full pass or reduced diameter ball valve. Product pipeline and storage equipment, the use of flange connected ball valve. City gas and natural gas pipeline, the use of flange connection and internal thread connection of the floating ball valve.
In the oxygen piping system of metallurgical system, the fixed ball valve with flange connection should be selected after strict degreasing treatment. Low temperature medium piping system and device should be selected with low temperature ball valve cover. The lifting rod ball valve can be used in the pipeline system of catalytic cracking unit of oil refining unit. Chemical system of acid and alkali and other corrosive media device and piping system, it is appropriate to choose austenitic stainless steel manufactured, PTFE valve seat sealing ring stainless steel. Metallurgical system, power system, petrochemical equipment, urban heating system in high temperature medium piping system or device, can choose metal to metal sealing ball valve. The need for flow regulation, can choose worm gear drive, pneumatic or electric with V-shaped opening of the ball valve.
Ball valve is very widely used, the variety and number of use is still continuing to expand, and to high pressure, high temperature, large mouth, high tightness, long life, excellent regulating performance and a valve multifunctional direction development, its reliability and other performance indicators have reached a higher level, and has been partially can replace gate valve, globe valve, regulating valve.
With the technological progress of ball valves, in the foreseeable short term, especially in oil and gas pipelines, oil refinery cracking device and nuclear industry will have a wider range of applications. In addition, in other industries in large and medium-sized caliber, low and medium pressure field, ball valve will also become one of the leading valve types.