What is a ball valve? and How does it work?

Posted by David Zheng on

A shut-off valve regulates the flow of the liquid or the gas using a rotary ball having a bore. Controlling the flow of the liquid, gases, and vapors in a piping system, the ball is mounted against two seats and has a shaft that connects it to the operating and control mechanism that rotates the ball. The fluid is not permitted to pass through the valve, with the cross-section of the bore being kept perpendicular to the flow of the fluid. Operated manually or through an actuator, the ball valve, the butterfly valve, and the plug valve behave as a quarter-turn valve. It is through the use of the wrench or the lever that the ball valve can be operated with ease and with less effort requirement. It is through the application of the torque that lets the lever arm rotates at 90 degrees. The parallel position of the lever arm concerning the pipe indicates the valve’s opening, whereas the perpendicular position denotes it’s closed. 

How does a ball valve work

Ball valves come in many designs and features to satisfy various industrial needs. The standards and specifications for ball valves vary depending on the industry where it is utilized. The basic components of the ball valve are as follows:

1) Valve Housing

JIVTO 1 PC Stainless steel ball valve

All the internal components of the ball valve are housed inside a body. The encasing is rugged and rigid material(the material usually chosen is thermoplastic). The thermoplastic metal’s rigid casing protects the internal components. The basic structural components of the wall housing determine the working of the external control mechanism causing the ball to rotate. 

2) The ball

The ball is a spherical-shaped component with a hole at the center. The hole in its center is called the bore. The bore serves as the flow opening of the fluid when the cross-section of the fluid flow path and the bore are coplanar. A ball, solid or hollow, determines the fluid flow through the cross-sectional area. Be it the opening diameter or the ones hollowed internally throughout the ball structure, how easily the fluid passes through the valve is determined by the ball.

3) The shaft

It is how the ball is connected to the control mechanism that eventually rotates the ball. The shaft has seals such as O-rings and packing rings to seal the shaft and the bonnet to avoid fluid leakage. A lever or a handwheel, the shaft can be operated manually or through the application of hydraulic, pneumatic,, or electric actuation. 

4) Bonnet

JIVTO 2 PC Stainless steel ball valve

Bonnet is the extension to the valve housing that contains and protects the shaft. Bolted or melted against the body, the bonnet is a hard metal component that a lever or a handwheel may manually operate. It can also be operated through hydraulic, pneumatic, and other mechanisms. 

5) Seat

Providing seating between the ball and the body, the seat is responsible for sealing the fluid inside and distributing the seating stress uniformly. The seat has high mechanical strength and great abrasion resistance and is divided into the upstream and the downstream seat. The upstream seat is adjacent to the inlet side of the valve. The downstream seat is found on the opposite side.

Advantages of the ball valves:

1)Ball valves induce a low-pressure drop compared to the other valve designs. A high-pressure drop, on the other hand, across a valve may result in turbulence and cavitation.

2)Ball valves require just the quarter of a lever turn to turn on and shut off fully. Flow control becomes much more restrictive and tremendously accessible.

3)The amount of torque required to operate a ball valve is not much. A small torque or actuator is needed for quick and efficient functioning. 

4)Ball valves are much more effective as they reduce the chances of leakages. The ball seals tight against the seats; thus, the fluid pressure is responsible for the sealing action. 


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