What are butterfly valves, and how are they useful?

by Sudarsan Chakraborty

A butterfly valve is a quarter-turn rotational valve for stopping, regulating, and starting flow. Devices like the Butterfly Valve can be used where space is limited because of its narrow profile. The disc completely stops the line when the valve is closed. The disc is at 90 degrees to the flow of liquid or gas when it is fully opened. The butterfly valve comprises only four parts:

Body: The valve bodies are typically designed to fit two pipe flanges, with the most prevalent wafer and lug body designs.

Disc: The disc is analogous to plugs in plug valves, gates in gate valves, or balls in ball valves in terms of stopping the flow. Different disc designs and orientations are used to optimise flow, sealing, and operating torque.

Stem: The stems can be one-piece shafts or two-piece (split-stem) designs. Most robust seated designs insulate the stem from the media, allowing for more effective material selection in cost and mechanical qualities.

Seat: The seat relies on an interference fit between the disc edge and the seat to produce cutoff. A variety of elastomers or polymers can produce seat material. The seat can be pressed or secured into place, or it might be attached to the body.

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The benefits

They are quick to open and easy to use: The valve can be completely closed or opened by rotating the handle 90 degrees. Large valves are frequently supplied with a gearbox, which connects the handwheel to the stem through gears. This makes the valve’s operation more straightforward, but it comes at the sacrifice of speed.

They are a relatively low-cost item to construct: Butterfly valves need less material because of their design. The wafer type, which goes between two pipeline flanges, is the most cost-effective. Bolts that unite the two pipe flanges and go through openings in the valve’s outer casing hold the lug wafer design in position between two pipe flanges. In addition, the materials are frequently less costly.

Butterfly valves take up less space: Due to their small design, butterfly valves take up less room than conventional valves.

Butterfly Valves are known for requiring little maintenance: Butterfly valves are popular because of their dependability and low maintenance requirements. Because of the reduced wear, this can extend the valve’s life. This lowers direct operating expenses and minimises the number of hours spent on valve maintenance.

The applications

Butterfly valves are commonly employed in various car systems. The Butterfly Valve in an automobile carburettor, for example, can be detected. As a result, the valve is used to control the airflow to the car’s engine. It can partially open and close to adjust the quantity of air that flows through it.

Because of its easy throttling capabilities and suitable pressure restrictions, butterfly valves are commonly used in pipes and tubes meant for firefighting. Abrasive and corrosive services are additional applications for these valves. They’re also employed in high-temperature, high-pressure steam and water facilities. Butterfly valves are also required for vacuum service, cooling, and circulating water systems. Additionally, some of its varieties, such as Triple Offset, are utilised in the oil, petrochemical, gas, chemical, power, and maritime industries. Valves also can be used for a modulating or on-off system.

Butterfly valve’s widespread use in commercial processes can be attributed in part to features such as quarter-turn operation, tight shut-off, and others. New component materials and designs have also boosted its application in industrial fluid systems.

Butterfly valves are helpful in pipelines because they assist control water flow. They are capable of stopping or starting any fluid flow and altering the flow of fluid. Some valves are better for corrosive systems, while some are better for high-pressure fluids. These valves are favoured because they cost less.

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