Principles of butterfly valve structure classification

1) Butterfly valve The butterfly valve is a valve that uses a disc-type opening and closing member to reciprocate about 90 degrees to open, close and adjust the fluid channel. The butterfly valve is not only simple in structure and volume. 1) The butterfly valve is a valve that uses a disc-type opening and closing member to reciprocate about 90 degrees to open, close and adjust the fluid channel. The butterfly valve is not only simple in structure, small in size, light in weight, low in material consumption, small in installation size, but also small in driving torque, easy and fast to operate, and it can also have good flow joint function and closing and sealing characteristics at the same time, which is nearly a dozen One of the fastest-growing valve varieties in recent years. Especially in developed countries such as the United States, Japan, Germany, France, and Italy, butterfly valves are widely used. The variety and number of its use continue to expand, and it is developing towards high temperature, high pressure, large diameter, high sealing, long life, excellent adjustment characteristics and multi-function of a valve. Its reliability and other performance indicators are all high. Level, and has partially replaced the globe valve, gate valve and ball valve. With the advancement of butterfly valve technology. In the foreseeable short period of time, especially in the use of large and medium calibers and medium and low pressures, butterfly valves will become the dominant valve form. (Principle of butterfly valve structure classification) The original butterfly valve is a simple flapper valve that is not tightly closed. It is usually used as a flow regulating valve and a damping valve in a water piping system. (Principle of butterfly valve structure classification) With the application of chemically resistant synthetic rubber to butterfly valves, the performance of butterfly valves can be improved. Because synthetic rubber has the characteristics of corrosion resistance, erosion resistance, dimensional stability, good resilience, easy forming, low cost, etc., synthetic rubber with different properties can be selected according to different use requirements to meet the operating conditions of the butterfly valve. It is widely used in the manufacture of butterfly valve lining and elastic valve seat. (Principle of butterfly valve structure classification) Because PTFE has strong corrosion resistance, stable performance, not easy to age, low friction coefficient, easy to form, stable size, and it can also be filled and added with appropriate materials to improve its comprehensive performance. The butterfly valve sealing material with better strength and lower friction coefficient overcomes some of the limitations of synthetic rubber. Therefore, polymer materials represented by polytetrafluoroethylene and their filling modified materials have been widely used in butterfly valves. As a result, the performance of the butterfly valve has been further improved, and a butterfly valve with a wider temperature and pressure range, sealing performance and longer service life has appeared. (Principle of butterfly valve structure classification) In order to meet the use requirements of industrial applications such as high and low temperature, strong erosion, long life, etc., metal-sealed butterfly valves have been greatly developed in the past ten years. With the application of high temperature resistance, low temperature resistance, strong corrosion resistance, strong erosion resistance, and high strength alloy materials in butterfly valves, metal sealed butterfly valves have been widely used in industrial fields such as high and low temperatures, strong erosion, and long life. A butterfly valve with a large diameter of 9750mm, a high pressure of 2.2kN/cm2, and a wide temperature range of -102～606°C appeared, which brought the technology of the butterfly valve to a whole new level. Due to the application of computer-aided design CAD, computer-aided manufacturing CAM and flexible manufacturing system FMS in the valve industry, the design and manufacturing of butterfly valves have reached a new level. It not only completely innovated the design calculation method of the valve, but also reduced the heavy repetitive routine design work of the professional and technical personnel, so that the technicians have more energy to improve the technical performance of the product and the research and development of new products, shorten the cycle and improve Increased labor productivity. Especially in the field of metal-sealed butterfly valves, due to the application of CAD/CAM, a three-dimensional sealing pair designed by CAD and processed by cAM numerically controlled has appeared, so that the sealing surface of the valve is free from any squeezing, scratching, or abrasion during the opening and closing process. , So that the sealing performance and service life of the butterfly valve are improved by orders of magnitude. (The principle of butterfly valve structure classification) When the butterfly valve is fully opened, it has a small flow resistance. When the opening is between about 15° and 70°, it can perform sensitive flow control. Therefore, in the field of large-diameter adjustment, the butterfly valve has a small flow resistance. The application is very common and will gradually become the dominant valve type. Since the movement of the butterfly valve plate is wiping, most butterfly valves can be used for media with suspended solid particles. Depending on the strength of the seal, it can also be used for powder and granular media. 3.2.2 Classification of butterfly valves There are many types of butterfly valves, and there are many classification methods. 1. Classified according to the structure: 1 central sealing butterfly valve 2 single eccentric sealing butterfly valve 3 double eccentric sealing butterfly valve 4 triple eccentric sealing butterfly valve 2. Classified by sealing surface material 1 Soft sealing butterfly valve 1 The sealing pair is composed of non-metallic soft material to non-metallic soft material. 2 The sealing pair is composed of metal hard materials and non-metal soft materials. 3Metal hard seal butterfly valve. The sealing pair is composed of a metal hard material to a metal hard material. 3. According to the sealing form classification 1 compulsory sealing butterfly valve. 1 Elastic sealing butterfly valve. The specific sealing pressure is generated by the elasticity of the valve seat or the valve plate when the valve plate squeezes the valve seat when the valve is closed. 2External torque sealing butterfly valve. The seal specific pressure is generated by the torque applied to the valve shaft. 2 Pressurized sealing butterfly valve. The specific sealing pressure is generated by the pressure of the elastic sealing element on the valve seat or valve plate. 3 Automatic sealing butterfly valve. The sealing specific pressure is automatically generated by the medium pressure. 4. According to the working pressure classification 1 vacuum butterfly valve. Butterfly valves whose working pressure is lower than standard atmospheric pressure. 2 Low pressure butterfly valve. Butterfly valve with nominal pressure PN≤1.6MPa. 3 Medium pressure butterfly valve. Butterfly valve with nominal pressure PN of 2.5∽6.4MPa. 4 High pressure butterfly valve. The butterfly valve whose nominal pressure PN is 10.0∽80.OMPa. 5 Ultra-high pressure butterfly valve. Butterfly valve with nominal pressure PN>100MPa. 5. According to the working temperature classification 1 high temperature butterfly valve. Butterfly valve with t>450℃. 2Medium temperature butterfly valve. 120℃3 room temperature butterfly valve. -40℃4 low temperature butterfly valve. -100℃5 ultra-low temperature butterfly valve. Butterfly valve with t≤-100℃. 6. According to the connection method classification 1 pair clip butterfly valve 2 flange type butterfly valve 3 lug type butterfly valve 4 welded butterfly valve