Butterfly valve

The butterfly valve belongs to the quarter valve category. Quarter valves include valve types that can be opened or closed by turning the stem a quarter. In butterfly valves, there is a disc attached to the stem. When the rod rotates, it rotates the disc by a quarter, causing the disc to fall perpendicular to the fluid and stop flowing. To restore flow, the stem rotates the disc back to its original position, away from flow.

Butterfly valves are a popular choice because they are easy to install, inexpensive, and available in almost all sizes. These are typically used for regulatory services and switching purposes.

Butterfly valve application

Butterfly valves are important for processes and operations in many different industries. This is due to their size range and ability to control the flow of liquid, gas and mud. The butterfly valves can not only stop or start the flow, but also limit or reduce the flow as required when they are partially opened.

Customers from many industries purchase butterfly valves, including those in the fields of food processing (liquid), water plants, irrigation, pipeline manufacturing, industrial manufacturing, heating systems and chemical transportation.

Although butterfly valves have many different possible applications, some specific applications include vacuum, oil recovery, compressed air service, air and water cooling, HVAC, mud service, high-pressure water service, high-temperature water service, steam service and fire protection.

Due to the diversity of design and materials, butterfly valves have a wide range of applications. These can be installed in any pipe, from clean water to grinding fluid or slurry. These are typically used in mud or sludge applications, vacuum services, steam services, cooling water, air, or gas applications.

Advantages and disadvantages of butterfly valve

Butterfly valves provide users with many advantages. First, they have a compact design. Because of this compact design, they require less workspace than many other valves. Secondly, the maintenance cost of butterfly valve is quite low. Second, they provide high-quality traffic congestion. Again, they do not leak, but can be easily opened when needed. Another advantage of butterfly valve is its low price.

Advantages of butterfly valve

1. Because of their small size and compact design, the installation cost is very low.

2. These valves occupy very little space compared to other valves.

3. Automatic actuation makes it faster and more efficient than other valves.

4. Due to the multi disc design and fewer moving parts, it requires less maintenance, thus greatly reducing weathering.

5. The different seat materials make it easier to use in all types of environments, even abrasive environments.

6. Butterfly valves require less material, are easier to design and manufacture, and are generally more cost-effective than other types of valves.

7. Butterfly valves can be used in a variety of applications, including underground installations.

Disadvantages of butterfly valve

Indeed, the disadvantages of butterfly valves outweigh the advantages. But before using these valves, there are still some things to remember.

1. Even when fully open, a small area of the disc will prevent material flow. This may affect the movement of the disc position and the pressure switch in the pipe.

2. The sealing function is not as good as some other valves.

3. Throttling is only applicable to low differential pressure service.

4. The butterfly valve always has the risk of blocking the flow or cavitation.

Butterfly valve structure

Butterfly valves have several main characteristics. These include the body, disc, stem, and seat. They also have an actuator, such as a lever. The operator can rotate the valve actuator to change the disc position.

The valve body is installed between two pipe flanges. The most common of all different body designs are lugs and discs.

The working principle of the valve disc is similar to the gate in the gate valve, the plug in the plug valve, the ball in the ball valve, etc. When it is rotated 90 ° to flow parallel to the fluid, the disc is in the open position. In this position, the disc will allow all fluid to pass through. When the disc rotates again, the disc enters the closed position and prevents fluid flow. Depending on the disc orientation and design, the manufacturer can manipulate the operating torque, seal and/or flow.

The valve stem is a shaft. It can be one or two pieces. If it is the latter, it is called split stem.

The seat is connected to the vehicle body by pressing, bonding or locking mechanisms. The manufacturer usually makes the valve seat with polymer or elastomer. The purpose of the valve seat is to provide a closing function for the valve. This is why the rotating force required for butterfly valve closing is called “seat torque”, while the rotating force required for butterfly valve to rotate its closing element is called “off seat torque

The actuator can be mechanical or automatic, and the flow through the pipe can be adjusted by moving the valve disc. When closed, the valve disc covers the valve hole, and the fluid always contacts the valve disc. This will cause a pressure drop. To switch the position of the disc to give way to fluid flow, turn the stem a quarter turn.