## What is a Butterfly Valve?

Valves are necessary in water supply system, in order to regulate the flow of water and to minimize the wastage of water. Valves either start/stop the flow of water or control (throttling) the speed and capacity of water or direct the flow in one direction only.

##### Also Read: What are different types of valves?

A butterfly valve’s function is to start/stop and throttle (control) flow of water passing through it. It consists of a disc which is attached to a rotating shaft. The disc is rotated with the help of shaft to block or unblock the flow of water.  Butterfly valve is a quarter turn valve i.e opening and closing of valve is done by turning it ¼ (90°)

Courtesy – Super Brainy Beans

### Functions of Butterfly Valve:

01. Open Condition: In open condition the disc is rotated to align in the direction of flow of water. When disc aligns in the direction of flow it allows the flow of water with minimal resistance.

02. Closed Condition: In closed condition the disc is rotated to align the direction perpendicular to the flow of water. Hence, blocking the flow of water.

03. Partially open: The valve can partially be kept open in order to control flow.

Courtesy - Wermac

There are mainly two types of Butterfly valves available in market-

Double Flanged Valve: It is a butterfly valve having flanged ends for connection to pipe flanges by individual bolting

Wafer Valve: It is a butterfly valve for clamping between pipe flanges using through bolting.

Courtesy: Assured Automation