Butterfly valves in India and around the globe are a type of industrial valves used to control the flow through a circular pipe or tube. Generally, the material of which the flow is controlled with tends to be air, gas, steam, or liquid. Sometimes, certain dry materials are also handled through a butterfly valve. The valve consists of a circular disc with its pivot axis, which is perpendicular to the direction of the material flowing. Butterfly valves are made up of a body, seat, disc, stem, and actuator. Its trim features a variety of materials that are used to configure each of the component parts. Combining its trip features properly to address the material and environment is critical when choosing the correct model valve for its intended application.
Cast iron, aluminum, carbon steel, ductile iron, stainless steel, and even exotic metals are used to manufacture butterfly valves India. These valves are available in lug and water style. Lug valves contain tapped holes that enable them to be bolted directly to a mating flange. The valve, in the closed position, independently seals the material to the upstream and downstream side. Lug valves, because of this independent sealing, may be used to isolate downstream equipment that may require replacement or maintenance. On the other hand, wafer style valves are installed and sandwiched between pipe flanges, one which is easier to replace or install. However, the conveying line is required to be drained when replacing a water valve. There is nothing to seal material either upstream or downstream from the removal point, once the valve is removed.
The most commonly used types are the resilient seated valves. An elastomer seat is lined with the interior of the body. Seats are manufactured by using buna, EPDM, Teflon, Viton, Carbox, Chlorbutol, white buna, natural rubber, or white neoprene as well as other materials. Temperatures, pressures, and material handle influence the choice of the seat material. The seats of some low-cost butterfly valves India are generally molded into the body and cannot be repaired or replaced. The removable seats, however, are generally used in precision butterfly valves which are repairable or replaceable.
Controlled by the actuator, the valve disc regulates the flow of material within the conveying line. The disc is generally made up of materials such as stainless steel, ductile iron, aluminum/bronze, ductile/epoxy coated, ductile/nylon II coated, ductile/nickel plated as well as others. Care should be taken in specifying the proper material of the disc shape and construction as the disc is directly in the material flow stream. Some discs are made to allow increased flow patterns through the piping.
Passing through the center valve, the stem attaches the valve to the actuator and positions the disc for material flow control and shuts off. The stems may be one or two-piece construction, depending on the application and valve size. Typically, the construction materials include carbon steel as well as different grades of stainless steel.
Different types of actuators are used in butterfly valves, such as gear, manual handle, electric, pneumatic, and electro-hydraulic. Moreover, actuators that are enclosed in special housings and buried are generally available for certain underground applications.
As mentioned earlier, butterfly valves in India are commonly used in most air, gas, steam, and liquid applications. These valves offer an economically priced, excellent, positive shut-off valve for handling the materials that are easily displaced by the valve disc as it closes. Butterfly valves provide a reliable, bubble-tight, bi-directional shut off when handling this type of material.