Butterfly Valves
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Butterfly valves are designed to regulate or isolate the flow in a system. The valve has the ability to start, stop or restrict the flow in a system pipeline and is used for repairs, cleaning or alterations of fluids when no fluid is running through the pipeline.
A butterfly valve does not look much like a butterfly and it operates in quarter turn. The valve has to completely open to completely close in a 90-degree turn movement. Thus, the valve allows for a quick opening and closure. The butterfly name comes from the fact that the disc or wing moves around a central axis, which acts like the body of a butterfly. |
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Product Specifications
For more information on the individual product specifications, please click on the links below:
What are butterfly valves
1. Why is it called a butterfly valve?
The valve closing mechanism is a disc connected to a rod. It closes when the rod rotates the disc by a quarter 90-degree turn to a position perpendicular to the flow direction. The disc is then rotated back to allow the flow when the valve is at an open position. Butterfly valves have a popular valve design due to the light weight, low in cost, quick operation, installation footprint and availability of their massive size range. The valve can be operated by manual handles, gearbox or automatic actuators.
The valve closing mechanism is a disc connected to a rod. It closes when the rod rotates the disc by a quarter 90-degree turn to a position perpendicular to the flow direction. The disc is then rotated back to allow the flow when the valve is at an open position. Butterfly valves have a popular valve design due to the light weight, low in cost, quick operation, installation footprint and availability of their massive size range. The valve can be operated by manual handles, gearbox or automatic actuators.
2. What is the function of a butterfly valve?
Basically, the valve can be operated manually by handle and gear or automatically by electric, pneumatic or hydraulic actuators. These devices allow precise rotation of the disc to positions ranging from fully opened to closed position.
Basically, the valve can be operated manually by handle and gear or automatically by electric, pneumatic or hydraulic actuators. These devices allow precise rotation of the disc to positions ranging from fully opened to closed position.
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Manual actuation is considered an economic and inexpensive method. In addition, it is easy to operate. The two common methods are hand lever and gear:
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Automatic actuation is a reliable method of controlling valves from a remote location. The actuators make rapid operation of larger valves possible. Actuators can be designed to fail-open (stay opened in case of actuator failure), fail-close (stay closed in case of actuator failure) and often come with a manual actuation method in case of any failures. There are three types of automatic actuators:
Butterfly valves are made up of major components such as seat, disc, body and actuator.
- Electric: Uses an electric motor to control the valve by turning the valve stem.
- Pneumatic: Requires compressed air to move a diaphragm or piston to control the valve.
- Hydraulic: Requires a hydraulic pressure to move the diaphragm or piston to control the valve.
Butterfly valves are made up of major components such as seat, disc, body and actuator.
- Seat: The seat is usually made of some kind of rubber material to ensure that there will be a tight and secure sealing when the valve is in closed position. If the valve stops operating correctly, there is a possibility that the seat has been damaged in some way.
- Disc: The disc is a critical component in the valve design. The valve opens when the disc turns and it gives the disc a butterfly like appearance. The disc is moved by the actuator or manual handle and can be in a fully closed or opened position.
- Body: The body is used to connect valves with pipes or fittings. It is everything around the seat of the valve and makes up a good quantity of the valve structure.
- Actuator: This part is called a handle or operator. It controls how far opened or closed the butterfly valve and it is a handle that moves 90 degrees. Actuator is an optional installation as the standard valve comes with a handle.
3. What type of valve is a butterfly valve?
Butterfly valves are connected to the piping system in different ways. The most common methods are wafer type and lug type.
Butterfly valves are connected to the piping system in different ways. The most common methods are wafer type and lug type.
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A wafer type is the most common and economical type and it is sandwiched between two pipe flanges. This valve has the option to own flange holes outside of the valve body. The pipe flanges are connected through long bolts that cross the entire valve body and the sealing between the valve and pipe flanges is achieved by a gasket, flat valve and O-rings faces on both sides of the valve. The connection is designed for sealing against bi-directional differential pressure and to prevent backflow in systems designed for universal flow. To replace the valve or pipes, shutting down the system is required.
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A lug type has threaded inserts outside both sides of the valve body. Two sets of bolts connect the pipe flanges to each side of the bolt inserts with bolt thread in the middle without nuts and the design enables the disconnection of one side without affecting the other for dead-end connection service. A separate set of bolts for each flange side is being used when the valve is installed between two flanges. Lug type valves are suggested to apply in dead end service generally have a lower running pressure rating. With that, each length of pipe can be removed and replaced independently. Basically there are 8 or 12 lugs where 4 or 6 lugs are used to connect the each pipe section line. The lug type unlike the wafer style can carry the weight of the piping through the valve body.
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4. What is the purpose of butterfly valve?
The butterfly valve can be used for a huge range of applications. They are performing well in large volume water and slurry applications.
There are many advantages in applying butterfly valve design in system installation.
The butterfly valve can be used for a huge range of applications. They are performing well in large volume water and slurry applications.
- Wastewater treatment, water supply
- Slurry and similar services
- Fire protection
- Compressed air and gas application
- Vacuum service
- Chemical and oil industries
- Fuel handling systems
- Power generation
There are many advantages in applying butterfly valve design in system installation.
- Easy and fast to open: A 90-degree rotation of the handle provides a complete closure or opening of valve. Large size valve requires a gearbox where the hand wheel by gears is connected to the stem. This simplifies the operation of the valve.
- Lesser space requirements: The compact design which requires considerably less space compared to other valve design.
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5. How do you install a wafer butterfly valve?
The quality of butterfly valve installation is one of the most important factors that affect the overall operation. To connect pipe to another pipe connection, two flanges are needed to clamp the butterfly valve in the middle. The structure of the wafer type butterfly valve is short and takes up a small space. Select the special flange standard for butterfly valves before installing.
Position the fixed wafer flange in the flange middle at the both ends pipe and use the bolts to pass through the special flange and pipe flange of the clip on the valve. The fluid liquid medium in the pipeline can be controlled and the wafer butterfly valve’s small footprint makes it particularly suitable for system applications where room space is limited or where the distance between pipes are comparatively small. Please refer to specific installation steps below:
The quality of butterfly valve installation is one of the most important factors that affect the overall operation. To connect pipe to another pipe connection, two flanges are needed to clamp the butterfly valve in the middle. The structure of the wafer type butterfly valve is short and takes up a small space. Select the special flange standard for butterfly valves before installing.
Position the fixed wafer flange in the flange middle at the both ends pipe and use the bolts to pass through the special flange and pipe flange of the clip on the valve. The fluid liquid medium in the pipeline can be controlled and the wafer butterfly valve’s small footprint makes it particularly suitable for system applications where room space is limited or where the distance between pipes are comparatively small. Please refer to specific installation steps below:
- Step 1: Place the butterfly valve in between the pre-install two pieces’ butterfly valve flange. Ensure the flange bolt holes are aligned with the butterfly valve body circular holes.
- Step 2: Insert the bolt and nut into the flange hole to connect with the valve body and flange. Correct the flatness in the method and tighten bolt and nut according to torque tightening value.
- Step 3: Welding the flange on the pipe by using spot welding.
- Step 4: Take out the butterfly valve first.
- Step 5: Weld the two flanges completely to the pipe end and complete the fixation.
- Step 6: The clamping butterfly valve shall be installed after the flange is cooled with the welding section of the pipe.
- Step 7: Make a correction to the installation position of the valve and tighten up with the bolt by following the tightening torque value. Be careful not to over tighten it.
- Step 8: Open fully the butterfly valve plate to ensure that it can be open and close freely.
- Step 9: Cross the bolt and tighten it evenly once again.
- Step 10: All the steps are completed. Ensure the valve is free to switch by testing of the opening and closing of the butterfly valve once again.
6. Can butterfly valves be installed upside down?
The butterfly valve plays a sealing role with the valve seat seal and the valve shaft part of the packing. The medium will have little erosion on the filler when the valve is mounted horizontally or vertically on the pipeline installation. The medium will flow to the filler to erode the filler if the butterfly valve is installed upside down. It would destroy the sealing performance and cause the leakage of the valve. The leakage of poisonous and harmful medium will cause safety risks and system damage.
In additional to not flipping, please take note the point of installation below:
The butterfly valve plays a sealing role with the valve seat seal and the valve shaft part of the packing. The medium will have little erosion on the filler when the valve is mounted horizontally or vertically on the pipeline installation. The medium will flow to the filler to erode the filler if the butterfly valve is installed upside down. It would destroy the sealing performance and cause the leakage of the valve. The leakage of poisonous and harmful medium will cause safety risks and system damage.
In additional to not flipping, please take note the point of installation below:
- 4.1 Before installation, to ensure that the media flow space is clean and free of impurities by cleaning the internal pipeline inside the butterfly valve. Close the disc only when it has been cleaned.
- 4.2 Check on the flange standard for butterfly valve upon installing.
- 4.3 Each connecting component parts of the butterfly valve should be compacted, so that it would ensure the packing part obtains the maximum sealing performance. This shouldn’t affect the rotation of the valve stem.
- 4.4 Perform periodic inspections during the operation process and find the problem is solved in a timely manner after valve installation.
