What is ball valve ?.
A ball valve is a flow control device that uses a rotating ball with a hollow hole to control the flow of fluid through the ball.
It opens when the hole in the center of the ball lines up with the inlet, and closes to cut off flow by turning the valve handle 90 degrees .
The handle lies flat with the flow when open and perpendicular to the flow when closed, making it easier to visually check the status of the valve .
The 1/4 turn closed position can be either clockwise or counterclockwise.
Ball valves are durable, perform well after many cycles, and remain reliable and close tightly even when not in use for long periods of time.
These characteristics make these valves an excellent choice for isolation and control applications and are often preferred over gate and globe valves, but they lack the precise control of these alternatives in throttling applications. .
The operation, ease of repair, and versatility of ball valves enable a wide range of industrial applications, with pressures up to 1,000 bar (100 MPa; 15,000 psi) and up to 750° depending on the design and materials used. Suitable for temperatures of F (400°C). Sizes typically range from 5 to 1200 mm.
The valve body is made of metal, including metal, plastic, or ceramic. Floating balls are often chrome plated for added durability. One disadvantage of ball valves is that when used to control water flow, water becomes trapped in the central cavity when in the closed position.
When ambient temperatures drop below freezing, the expansion associated with ice formation can cause cracks to form on the sides .
Insulating tape or heat tape can usually prevent damage in this situation. Another option for cold regions is a "frost resistant ball valve." This type of ball valve has a freeze plug on the side, so in the event of a freeze, the freeze plug breaks off and acts as a "sacrificial" failure point, making it easier to repair.
Instead of replacing the entire valve, you can simply install a new freeze plug .
For cryogenic liquids or products that may expand within the ball, a vent is drilled upstream of the valve.
This is called a bent ball. Ball valves should not be confused with "ball check valves," a type of check valve that uses a solid ball to prevent unwanted backflow.
Demonstrates excellent leakage performance. void filler edit Many industries are experiencing problems with residue in ball valves.
Residues can also pose a health hazard if the liquid is intended for human consumption, and if the liquid changes from time to time, one liquid can become contaminated with another.
The half-open position of a ball valve creates a gap between the ball bore and the housing that can trap liquid, resulting in residue. To prevent liquid from entering this cavity, it must be sealed.
This can be achieved by extending the seat so that it is always in contact with the ball. This type of ball valve is known as a cavity-filled ball valve.
There are several types of ball valves related to ball installation and lateral movement. Body materials include, but are not limited to: stainless steel ,Brass, bronze ,chromium, Titanium, PVC, CPVC
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