The newer design of butterfly valve has been introduced into the fleet and is gradually replacing the older design. Unlike the older style of butterfly valve, the new style has a removable retaining ring that holds the seat in place. To open or close a butterfly valve, turn the handle only one quarter of a turn to rotate the disk 90 degrees. Some larger butterfly valves may have handwheels or actuators that are driven by pneumatic, electric, or hydraulic means through a gearing arrangement. Ball Valves Ball valves, as the name implies, are stop valves that use a ball to stop or start the flow of fluid.
Most ball valves are the quick-acting type.
They require only a 90-degree turn to operate the valve either completely open or closed. When the valve handle is operated to open the valve, the ball rotates to a point where the hole through the ball is in line with the valve body inlet and outlet. When the ball is rotated so the hole is perpen-dicular to the openings of the valve body, flow is stopped. Integrated Publishing's Official Web Page Click here for a current index of everything on this web site. All Rights Reserved.