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Flanged butterfly valves are mainly used in industrial production pipelines, its role is mainly to cut off the circulation of the medium in the pipeline, or adjust the size of the medium flow in the pipeline.
Flanged butterfly valves are widely used in water conservancy projects, water treatment, petroleum, chemical industry, city heating and other general industries in the production pipeline, but also in the thermoelectric power plant condenser and cooling water system on the use.
Flanged butterfly valves are especially suitable for making large diameter valves, which are widely used in the field of large diameter regulation. When the flanged butterfly valves are fully open, the flow resistance is small, and when the butterfly plate opens at an angle between about 15-70°, the flanged butterfly valves can be very sensitive to control the flow of the medium.
In addition, because the butterfly plate of flanged butterfly valve has wiping property when doing rotary movement, so this kind of valve can be used in the pipeline with suspended particles of media, according to the strength of the sealing member, it can also be used in the pipeline of powder and granular media.
Flanged butterfly valve can be divided into soft seal flange butterfly valve and hard seal flange butterfly valve according to the sealing surface material.
Soft seal flange butterfly valve sealing vice is rubber, fluorine plastic and other elastic sealing materials;
Hard sealing flange butterfly valve sealing vice is metal-to-metal, metal-to-fluoroplastic and multi-layer composite plate.
The sealing ring of soft seal flanged butterfly valve can be inlaid in the channel of the valve body, and can be inlaid in the periphery of the butterfly plate, when it is used as a shut-off valve, its sealing performance can reach FCI70-2:2006 (ASME B16 - 104) Class VI, which is much higher than that of the hard seal flanged butterfly valve; however, due to the limitation of using temperature because of the soft sealing material, the soft seal flanged butterfly valve is usually used in the Water conservancy and water treatment fields at room temperature.
Metal hard seal flange butterfly valve has the advantage of material, can adapt to higher working temperature, greater working pressure, service life is also longer than the soft seal, but hard seal flange butterfly valve shortcomings are also very obvious, it is difficult to do complete sealing, sealing performance is very poor, so this kind of flange butterfly valve is generally used in the occasions that do not have high requirements on sealing performance to do to regulate the flow of use.
Double eccentric seal butterfly valve adopts eccentric structure design, the main structure of the valve by the valve body, butterfly plate, valve seat, valve stem and transmission mechanism and other components, the valve seat can be dismantled structure, and according to the physical and chemical properties of different media, the selection of the corresponding corrosion resistance, light resistance, aging resistance materials, can be widely used in water supply and drainage, sewage, construction, air conditioning, petroleum, chemical, food, medicine, textile, paper, Hydropower, ships, metallurgy, energy systems and other fluid pipelines as a regulating and intercepting device to use.
Double eccentric butterfly valve usually adopts PTFE material as its sealing valve seat, and can also adopt metal sealing valve seat to expand its application in high temperature field. But the sealing of double eccentric butterfly valve with metal sealing seat still belongs to the position sealing structure, i.e., the sealing surface of butterfly plate and valve seat is in line contact, so it is not able to withstand high pressure, which will inevitably lead to a larger leakage when applied in high-pressure system, so double eccentric butterfly valves with metal sealing seat should be avoided as much as possible in high-pressure or the system that requires the cut-off to be tight.
Three eccentric butterfly valves Yang various valves of the long, avoid various valves of the short, more and more by the majority of users and designers of the importance of. Its maximum pressure level can reach 2500 pounds, the standard calibre can be done 48 inches, and the clamp, lug, flange, ring, butt welding, jacket, various structure length can be corresponded to, due to the material choice of a large margin of choice, high and low temperatures and a variety of acids, alkalis, and other corrosive media can be corresponded to the self-efficacy. Especially in large calibre, with its zero-leakage advantage, it is constantly replacing the bulky gate and ball valves in shut-off valves, and likewise, with its excellent regulating function, it is constantly replacing the bulky globe valves in regulating valves.
Eccentric sealed butterfly valves are used in various important pipelines such as process control in major industrial fields including oil and gas extraction, offshore platforms, oil refining, petrochemicals, inorganic chemicals, energy generation and so on, including China. In the actual project, if the working pressure of the system is not less than 1.0 MPa or in the important parts that need to be opened frequently, eccentric butterfly valves can be used.
