The Performance of Ball Valves
The ball channel of the ball valve
is circular; the circular flow runner of the non-reduced ball is connected with the circular flow runner of the valve body, which forms a straight section. So the ball valve
has small flow resistance. According to different working conditions, we can choose the metal, metal and metal, nonmetal and metal as well as nonmetal sealed auxiliary which has good sealing performance. Ball valve has the advantages of the small size, fast opening and closing, easy operation, long service lives, wide application ranges, being safe & reliable, etc. , which make ball valves can replace some of the gate valves, globe valves and throttle valves. Multiport ball valves can be used in allocating media and changing the flow directions of media.
The ball valve has developed rapidly in recent years. With the development of manufacturing technology of the ball valve
, it can be expected that the ball valve will be more widely used.
The sealing ring of the inlet and outlet valve seat can be designed with different diameters and designed into the inlet seal (front sealing of valve), the outlet seal (back sealing of valve
) and the bi-directional seal (front and back seal) through utilizing the piston effect.
Advantages of ball valves
( 1 ) Ball valves have small flow resistance.
( 2 ) Ball valves have simple structures, symmetrical valve bodies small sizes, bidirectional flow and bi-directional sealing.
( 3 ) Ball valves
have reliable sealing performance (especially when the sealing surface of the valve seat made of nonmetallic materials)
( 4 ) Ball valves have features of convenient operation, rapid opening and closing. They can be operated through being rotated 90 degree and are easy to remotely control.
( 5 ) Ball valves are easy to be maintained. The valves' sealing rings are generally active, and it is convenient for disassembly and replacement.
( 6 ) When the ball valve is fully open or closed, the sealed auxiliary is completely insulated from the media, which can prevent the the sealed auxiliary from the erosion of media.
( 7 ) The opening process of the ball valve
is a spin wipe process. So most structures of ball valves are suitable for media containing suspended solid particles. The ball valve with the valve seat made of appropriate sealing materials with wear resistance can also be used for the powder media.
( 8 ) Through-way ball valves are used to cutting off the media and have a wide range of applications. There are also the three-way, four-way and five-way ball valves which are used to allocate media and change their flow directions. V-shaped ball valves can be used to throttle media.
( 9 ) When the full bore ball valves are fully open, it is easy for the pigging balls to go through the pigging pipelines. This feature of the full bore ball valves makes them widely used in the natural gas pipelines.
( 10 ) Ball valves
have a wide range of applications. They can be used under the vacuum as well as the high pressure conditions. They are suitable for pipes with diameters from DN8 to DN3000. They can be applied to the working temperature from -254℃ to 815℃.
The disadvantages of ball valves
( 1 ) If the parts such as sealing rings of the ball valves' valve seats are made of non-metallic materials, the rating pressure and temperature of the parts will be lower than those of the metal ball shells. Thus, the actual working pressure, temperature and medium of ball valves
are restricted due to this reason.
( 2 ) When the sealing ring of the ball valve's valve seat is made of the non-metallic material, we should take fire resistance and anti-static performance of the ball valve into consideration.
( 3 ) It is difficult to process and grind the ball of the ball valve, especially for the ball valve with the metal sealed auxiliary and for the hard sealed ball valve.
( 4 ) When the active sealing ring of the ball valve is filled with dust, coking media and viscous media, the valve seat will be affected and have displacement, which will further influence the sealing performance of the ball valve. Therefore, the ball valves are unsuitable for the working conditions containing coking and viscous media.