Brief Introduction to Selection Method of Ball Valve

Selection method of ball valve:

The working principle of the ball valve is to make the valve open or blocked by rotating the ball. Ball valve switch is light, small, can be made into a large caliber, reliable seal, simple structure, easy maintenance, sealing surface and sphere are often in closed state, not easy to be eroded by media, widely used in various industries.

Ball valves can be roughly divided into 19 categories, including floating ball valves, fixed ball valves, metal hard seal ball valves, V-type ball valves, pair-clamp ball valves, heat preservation ball valves, pipeline ball valves, track ball valves, top-mounted ball valves, pigging valves, high-pressure forged ball valves, three-way (four-way) ball valves, internal thread ball valves, integral ball valves, low-temperature ball valves, bellows ball valves, eccentric hemisphere valves, all-welded ball valves, special type ball valves. Ball valves, etc.

O-type ball valve adopts floating structure, ball core is precision casting, hard chromium plating on the surface, valve seat is made of metal or reinforced polytetrafluoroethylene material, runner mouth and pipeline diameter are the same, flow capacity is great, flow resistance is very small, no leakage when closed, generally used as switch valve, especially for high viscosity, containing fibers, granular media.

V-type ball valve adopts fixed structure, with V-type notch on the ball core, which can realize proportional adjustment, and the flow characteristics are approximately equal percentage.

Ball valves have a wide range of applications. Ball valves can be applied to:

1. The nominal diameter ranges from 8 mm to 1200 mm.

2. The nominal pressure ranges from vacuum to 42 MPa.

3. The working temperature ranges from - 204 C to 815 C.

Especially in petroleum, chemical, metallurgical and other departments, the use of soft sealing ball valves in flammable and explosive media equipment and pipeline systems should pay more attention to fire resistance and fire prevention.

Usually, ball valves are recommended in pipeline systems with two-position regulation, strict sealing performance, mud, abrasion, shrinkage passage, quick opening and closing action (1/4 turn-on and closing), high pressure cut-off (large pressure difference), low noise, cavitation and gasification, small leakage to the atmosphere, small operating moment and small fluid resistance.

Ball valves are also suitable for piping systems with light structure, low pressure cut-off (low pressure difference) and corrosive media.

Ball valves can also be used in cryogenic (cryogenic) devices and pipeline systems.

When adjusting performance is required, ball valves with special V-shaped openings should be selected.

In petroleum, petrochemical, chemical, power and urban construction, metal-to-metal sealed ball valves can be selected for pipeline systems operating at temperatures above 200 degrees Celsius.

In the oxygen pipeline system of metallurgical industry, it is necessary to use ball valves after strict degreasing treatment.

When the main pipelines in oil and gas pipelines need to be buried underground, full-diameter welded ball valves should be used.

Ball valves are widely used in irrigation systems, mainly at the entrance of branch pipes. The ball valve has simple structure, small volume and little resistance to water flow. The disadvantage is that it opens or closes too fast, and it will produce water hammer in the pipeline (when the water velocity changes suddenly, the pressure will rise). Therefore, ball valves should not be used in trunk pipes. They can be used for flushing on trunk pipes, branch pipes or their ends. The effect of flushing and sewage is good.