Design of the ball valve

The main elements of a ball valve are:

A ball valve made of polished stainless steel
A body made of steel or cast iron
Fluoroplastic rings that seal the valve
A steel stem with a set of sealing rings

Split body ball valves are used in areas where maintenance personnel have free access, such as boiler rooms, thermal power plants, and industrial facilities. Compared to solid welded valves, split valves are easier to repair, have higher metal content, and are correspondingly more expensive.

A split body ball valve is designed to allow for repairs and maintenance. The seal of the flow closure is ensured by compressing the fluoroplastic seals against the polished surface of the ball with tightening bolts, which can be tightened when necessary.

Solid welded ball valves are used in heating networks, boiler rooms, and thermal power plants. They do not require maintenance, are highly reliable and inexpensive, but are not suitable for repair and must be replaced if they fail.

The seal of the flow closure is ensured by pressing the fluoroplastic seals against the polished surface of the ball with disc springs.

Floating ball valves have a slot in the ball valve into which the flat end of the stem is inserted. When closed, the direction of the slot coincides with the axis of the pipeline, and the ball can be slightly displaced, pressing against the end seal under the action of the working environment.

On pipelines with a large diameter and high pressure of the working environment, considerable effort may be required to open a floating ball valve. Therefore, valves of this design are usually made with a diameter of no more than DN200. To facilitate closure, the fixing shaft may have sliding bearings.

Trunnion-mounted ball valves have a ball valve that is rigidly mounted on the shaft axis and cannot move linearly in the body. Less effort is required to close the valve, but its design is more complex than that of floating ball valves with a moving valve, and it is more expensive.

Full-bore ball valves have a hole diameter in the valve that is equal to the internal diameter of the connected pipeline. They are distinguished by very low hydraulic resistance and a slight increase in dimensions, although they are somewhat more expensive than reduced-bore valves.

Reduced-bore ball valves (standard-pass) have a slightly smaller passage diameter in the valve than the internal diameter of the pipeline. Prices for ball valves with standard passage are lower than for full-bore valves, and their dimensions are smaller.