A butterfly valve is a particular type of valve that uses either a circular vane or a disc as the shut-off mechanism. Butterfly valves have a quick opening/closing quarter-turn mechanism that is used to control the flow of liquid through a piping system. They typically pivot on axes perpendicular to the direction of flow inside the flow chamber. Compared with ball valves, butterfly valves do not have pockets to trap fluids when the valve is in the closed position. Butterfly valves are frequently used as throttling devices, controlling the levels of flow in various positions: entirely closed, entirely open or partially open. They can control various substances of air, liquid or solid currents and are situated on a spindle that allows for flow in a single direction.
Butterfly valves are offered in many sized diameters, resulting in different flow rates. Smaller valve assemblies may be used where space is limited. Knowing the pipe dimensions, desired flow rate and material is important when considering a valve investment. Installation time is typically low compared to some other types of valves, and additional parts are unnecessary to work and maintain the valve.
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Butterfly valves have a lever that allows the operator to open or close the valve to control the flow. These valves are part of a family known as rotary valves, which are defined by the quarter turn that is used to move from the open to closed position and vice versa. This results in a lower surface friction, which means that these valves can be smaller than others and still operate efficiently.
Butterfly valves are available in numerous closure types and body configurations, depending on the type of flow control needed. These types of valves are commonly composed of metals, like aluminum and stainless steel, but also can be made from various plastics. One kind, flange butterfly valves, can be mounted between flanges. Another, lug butterfly valves, uses metal inserts that are attached to the valve's bolt holes. Using an independent set of bolts for each flange, this valve assembly is fixed between two flanges. Finally, wafer style butterfly valves are the cheapest and most popular type of butterfly valves because of their simplicity and ease of use.
Butterfly valves are used in many food transporting and chemical plants where controllable product flow is required. Other specific industries include HVAC, tertiary petroleum recovery and industries that use high pressure water. When properly used, butterfly valves offer many benefits. First of all, they are lower priced than many other types of valves, and generally have a longer life cycle. Butterfly valves are easy to maintain, are lightweight and compact and are able to handle a wide range of temperatures. These valves are also very reliable because of their tight shut-off, reducing the amount of leakage. One of the problems with butterfly valves, however, is that their design makes it difficult to efficiently and thoroughly clean all residual contaminants. Also, these valves are not good for use with highly abrasive or corrosive materials, because the disc can be easily eroded. Overall, butterfly valves are one of the fastest growing types of valves in the industry. |
