A Review Of The Components Of A Butterfly Valve

By Author: Reshma Lemos
Total Articles: 3
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A butterfly valve can be essentially defined equipment that has a rotating disc for controlling the media flow, in an industrial process, and is offered in a range of materials by the butterfly valve manufacturers. The disc is quite thin and offers little or no resistance to the flow of the medium. The butterfly valves have evolved to achieve great significance today, and they offer a range of functionalities including tight-shut off and a quarter turn operation. They can be used in a number of industrial operations, as they are made from a variety of materials.

While the early usage of the butterfly valves was in the areas relating to water applications, the new valves can be found in almost all kinds of chemicals plants, controlling the flow of a range of fluids.

The size of butterfly may range from 1 inch to more than 200 inches. Their pressure handling capability ranges from 150 psi to a greater limit of 740 psi. The high-performance butterfly valves may have a temperature rating of up to 450 degrees Fahrenheit.

The automatic actuators ...
... used in the valves may be of different kinds, including hydraulic, pneumatic or electric operators. The advantages offered by the butterfly valves include an economical and simple design that has lesser parts and can always be easily maintained and repaired. They also have a low cost of installation.

Basic Components of Butterfly Valves

The 4 main components of butterfly valves are described below.

1. Body
The body of the butterfly valve is fitted between 2 flanges. Water and lug are 2 kinds of body designs provided by the butterfly valve manufacturers. The lug body valve consists of lugs that protrude out of the valves and provide for body-fixing holes that can match the holes of the pipe’s flange. The water body butterfly valve does not have the protruding lugs. It is located between pipe flanges and the bolts of the flange surround the valve’s body. Water butterfly valve is inexpensive in comparison to the lug butterfly valve. The lug butterfly valve provides for dead-end service and for the removal of downstream piping.

2. Disk
The disk closes the flow of the butterfly valve. The disc is manufactured in different designs, so as to improve the flow of the medium, for providing better sealing and for operating the torque. The disk resembles the plug of the plug valve. You can rotate the disk for a quarter turn or for 90 degrees to open and close the valve.

3. Stem
The valve’s stem may have a 1 piece or a 2 piece design. The 2 piece design is also termed as a split stem. The stem is media-protected and helps in selecting the more efficient materials with regard to the mechanical and cost properties. Butterfly valves that are designed for having a high-performance quotient must be more compatible with the process, and must also possess more strength so that the disk can be easily seated, or unseated from the valve’s seat.

4. Seat
The seat provides for valve’s shut-off by utilizing the interface fit that lies between the edge of the disc and its seat. The seat can be made using different kinds of polymers.

The flush bottom ball valve is also used for the free flowing media when there is less space below the reactor, vessel or tank.