All You Need to Know About Ball Valves

BV

Ball Valve is designed to open/close the flow of liquid or gas without regulation. By turning the built-in handle with a 90 degree turn, this feature helps to open/close the flow within a second. It is available with a multi-port design ranging from 2 ports(min) up to 5 ports(max). As it has super-fast opening and closing speed, it can cause the water hammer effect. Water hammer effect is a phenomenon that occurs when the valve closes quickly and the flowing water inside the pipe hits the closed valve abruptly. This results in extremely high pressures in pipes and causes the water to flow backwards. Pipes may burst and joint leaks can happen when the pressures in the pipe are too high.

Types of Ball Valves 

A)Ball Type  

Floating Ball Valve 

FBV

Image credit: Theprocesspiping.com

• The ball is floating in the middle space of the valve and is secured by two sealing rings.


• Suitable for medium and low-pressure applications.

Trunnion Ball Valve 

TBV

Image credit: Theprocesspiping.com

• The ball is in a fixed position in the valve by a rod at the top and bottom, thus not allowing it to move freely. 


• Suitable for high pressure applications.

 

B)Housing Construction Type 

1p

One piece 

2p

Two piece

3p 

Three piece 

 Image credit: Pipingpipeline.com

One-piece: The body and the end connection parts in this ball valve are pressed or welded together in one piece. This feature helps to prevent outside contamination. However, cleaning and maintenance for this type of ball valve is impossible. Hence, it is commonly used in water storage systems and gas pipelines where outside contamination is not wanted.

Two-piece: This type of ball valve involves 2 separate pieces which is the body and one end connection (1 piece), and another end connection (1 piece). This feature helps to ensure that the port size matches the size of the pipe connected which ensures that there is no pressure drop. However, this type of ball valve needs to be completely removed from the connected pipe for cleaning or maintenance. Hence, it is suitable for any applications where constant pressure of the flow is required.

Three-piece: This type of ball valve consists of 3 separate pieces which is 2 end connections and the body. This feature helps to reduce the downtime for the pipeline system as cleaning or maintenance can be done on site without removing the whole valve from the pipeline itself. Hence, it is suitable for pharmaceutical and food/ beverage applications which require frequent cleaning.

WP BV

Fully Opened and Closed Ball Valve

Image Credit: Assuredautomation.com 

When built-in handle on top of ball valve is turned, the ball with a hole in the valve rotates so that the hole side faces the flow of liquid or gas. Then, the flow of liquid or gas can pass through the hole side. To close the ball valve, turn the handle in another direction, then the hole side of the ball is slowly turned to face the inner wall body of the valve. In this situation, the flow of liquid or gas is completely blocked by the ball.

Applications 

Based on the designs, materials used and the dimension of the ball valves, they can be implemented in residential, commercial and industrial services that require frequent on/off operation. The following are some common applications for ball valves:

● New plumbing systems 
● Fire protection systems
● Chemical manufacture plants
● Oil and gas processing, transportation, and storage applications

Advantages

- Ball valves are easy to operate.

- They can operate quickly.

- They are available in multi-port design.

-They have low pressure drop.

Disadvantages 

- Ball valves are not able to control flowrate.

-They are also not suitable for slurries/ solid matters.

-Water hammer effect can happen.