What is a butterfly valve скачать в хорошем качестве

What is a butterfly valve

The "butterfly" name comes from the fact that the disc, or "wings," moves around a central axis, which acts like the body of a butterfly. The butterfly valve like a ball valve or a plug valve is part of the quarter turn valve family. : t 1 quarter of a full revolution. The butterfly valve is designed to stop, throttle, and start flow. : Butterfly Valves have a short circular body, a round disc, with either metal-to-metal or soft seats. Similar to a trunnion ball valve the disc is anchored stem so the disc pivots as it operated. The valve may also be opened incrementally to throttle flow. Unlike a ball valve the disc is in the flow path and the pressure drop is greater. : The construction of a Butterfly Valve body varies. : A commonly used design is the wafer type that fits between two flanges. Another type, the lug wafer design, is held in place between two flanges by bolts that join the two flanges and pass through holes in the Valve's outer casing. The concentric butterfly valve is typically composed of a cast iron body, resilient rubber seat, and a stainless steel disc. Off camera: The stem is centered and the disk rotates concentric to the bore. The seal on the seat relies on the elastic deformation of the resilient seat as it closes. the disc as stated will usually be stainless, but will also be done in a bronze to save money or to be used in salt water applications. So lets take a closer look at the valve with this cutaway. The valve has the body here, the seat here, along with the disk and the stem. The butterfly valve has become popular as a substitute for gate and globe valves because of how light weight it is and the cost. In fact before we go over the advantages and disadvantages of the butterfly valve, lets od a quick … did you know? Did you know: __Butterflies Taste With Their Feet. __Butterflies have taste receptors on their feet to help them find their host plants and locate food. A female butterfly lands on different plants, drumming the leaves with her feet until the plant releases its juices. so know that we know that fun fact lets talk about the pros and cons of the butterfly valve Advantages of Butterfly Valves • Compact design requires considerably less space, compared to other Valves • Light in weight • Quick operation requires less time to open or close • Wide range of sizes • Low-pressure drop compared to a globe. Disadvantages of Butterfly Valves • Throttling service is limited to low differential pressure • Cavitation and choked flow are two potential concerns • Disc movement is affected by flow turbulence • The disc sealing surface is in the flow path. • Most Valves are unidirectional and will have a flow arrow. : so now that you know the pros and cons of the butterfly valve, let’s take a quick look at a High Performance butterfly valve with a (Double offset design) : The center of rotation is moved from the centerline of the valve body. The seat and seal design is conical or like the shape of a cone and on center. This design relies on elastic deformation seat to seal allowing a larger range of seat materials that can be used. The deformation is minimized by the double offset. As the disc opens it immediately moves away from the seat instead of across the seat. This design has the added capability of using line pressure to assist in the seal. there is also a triple offset design that we will go over in another class. Ok class lets do a quick review of the butterfly valve; Off camera: the butterfly valve is a quarter turn valve that is designed to stop, throttle, and start flow. it has a short circular body, a round disc, with either metal-to-metal or soft seats which makes it light weight and very cost effective. The 2 designs are design are a wafer type that fits between two flanges. And lug wafer design, which is held in place between two flanges. Finally the two most used types of butterfly valves are the concentric and the high performance double offset.