Construction of the ball valve

In the valve body, the shut-off element in the form of a ball with a hole is fixed on an axis perpendicular to the pipeline axis. A 90° rotation of the shaft is transmitted to the ball, moving it from the open position, where the axis of the hole coincides with the pipeline axis, to the closed position - moving the axis of the hole into a plane perpendicular to the flow direction.

The brass ball valve with a dismountable body is the most popular construction. It is characterized by a low price and lightweight. Brass ball valves are installed in internal heating systems as well as cold and hot water supply systems. The price of brass valves is so low that despite their ability to be disassembled, nobody bothers to repair them, and a non-working valve is simply replaced with a new one.

The only drawback of brass valves is the selective leaching of zinc, leaving copper. Manufacturers of high-quality valves have solved this problem by using brass resistant to leaching.

In ball valves installed on pipelines transporting drinking water, the internal surface is not nickel-plated in accordance with European standards.

The steel ball valve with a welded body is a very reliable and relatively inexpensive shut-off valve. They are designed for use in boiler houses, heating networks, heat points, and also in industrial installations. They are installed in critical pipeline sections where a long service life and high flow shut-off tightness are important.

Welded ball valves are non-repairable and must be replaced in case of failure. The tightness of the shut-off is ensured by pressing a Teflon gasket against the ball using a disc spring.

The steel ball valve with a dismountable body is typically used in industrial installations with high reliability, tightness, and repairability requirements. They are installed on pipelines transporting water, steam, and compressed air.

The main feature of the three-piece ball valve construction is the ability to replace the ball seals after dismantling the central part of the valve without unscrewing the threaded connection to the pipeline.

The tightness of the shut-off is ensured by pressing the Teflon sealing rings against the ball using tension bolts.

According to the design of the shut-off element, ball valves are divided into valves with fixed and floating balls.

In valves with a fixed ball, the shut-off element is firmly fixed on the vertical axis of the stem, and the seals that ensure tight flow shut-off are pressed against the ball by a disc spring or tension bolts.

In a valve with a floating ball, the shutter is not connected to the spindle and can move slightly within the body under the pressure of the working medium, providing additional sealing. On pipelines with large diameters and high working medium pressure, considerable force may be required to open the floating ball valve, which is why valves of this design are usually made with diameters not exceeding DN200.

In all threaded ball valves, the shut-off element is made with a movable shutter (ball).

According to the diameter of the hole in the shut-off element, ball valves are divided into full-bore valves, where the diameter of the hole is equal to the internal diameter of the connected pipeline, and reduced-bore valves, where the diameter of the hole is slightly smaller than the diameter of the pipeline.