Structural features
1, the valve has a simple structure , small size , light weight, material consumption province , installation of small size , fast switching , 90 ° reciprocating rotation, drive torque is small , etc., used to cut , turn , regulate the line of medium , fluid control features with good sealing performance and off . 2, the valve can be transported mud accumulation of fluid in the pipe mouth at least . Low pressure , can achieve a good seal. Adjusted performance. 3 , butterfly plate streamline design, the fluid resistance loss is small, can be described as an energy-saving products. 4 , the valve stem to pass rod structure , after quenching, has good mechanical properties and corrosion resistance , scratch resistance . Valve opening and closing the valve stem and not only for rotary motion for the lifting operation, the valve stem packing is not easy to destroy , reliable sealing . Taper pin with butterfly plate fixed to prevent out of extended end design, in order to avoid the junction stem and disc stem collapse unexpectedly break out . 5, the connections are flanged , wafer , welded connections and lug wafer connection. Drive form of manual , worm gear , electric, pneumatic , hydraulic, electro-hydraulic actuator linkage, etc. , can realize remote control and automation.
The advantage of butterfly
1 , open and close easily and quickly, saving, fluid resistance, can often operate . 2 , simple structure , small size and light weight. 3, you can carry mud accumulation of liquid in the pipe mouth at least . 4 , low pressure , it can achieve a good seal . 5 , regulate performance.
Butterfly shortcomings
1 , the use of pressure and operating temperature range is small . 2 , poor sealing . Butterfly form of the structure can be divided into the bias plate , vertical plate , swash plate and leveraged . Press the seal can be divided into soft and hard seal sealed type. Soft rubber ring seal type commonly used seal seal type commonly used metal ring seal . By connection type can be divided into flange connection and clamp connections ; press can be divided into manual transmission , gear , pneumatic, hydraulic and electric types .
Valve installation and maintenance
1 , during installation , the valve to stop in the closed position. Butterfly
2 , the open position should the rotation angle of the disc to determine. 3 , with a bypass valve butterfly valve, open the bypass valve opening should be preceded . 4 , shall be the manufacturers installation instructions for installation , heavy butterfly , set a solid foundation.
Selection of butterfly
Butterfly butterfly plate mounted on the pipe diameter direction . In the valve body, the cylindrical passage , the disc -shaped disc around the axis of rotation, angle of rotation between 0 ° -90 ° , rotation to 90 ° when the valve is in the fully open state. Butterfly simple structure , small size , light weight, by only a few parts . And just rotate 90 ° to quickly open and close, easy to operate , while the fluid control valve has good features . Valve in the fully open position, the disc thickness is the only medium flows through the resistance of the valve body , through the valve so that the pressure drop generated is small, it has a better flow control characteristics . There are bombs and metal sealing butterfly valve sealing two kinds of seal type . Elastic sealing valves, seals can be mounted on the body or attached to the disc periphery. Metal sealed valve generally higher than the elastic sealing valves , long life, but it is difficult to completely seal. Metal seal can accommodate the higher operating temperature , the elastic seal is a temperature limit of defects. If the requested use as a flow control valve , main valve of choice is the right size and type. Butterfly structure principle is particularly suitable for the production of large diameter valves . Butterfly not only in oil , gas, chemical, water treatment and other general industries are widely used , but also used in thermal power plant cooling water system. Common butterfly valve wafer type butterfly valve and flange type butterfly two kinds . Wafer type butterfly valve is connected to the valve stud in two pipe flanges , flange type butterfly valve is a valve with a flange bolt flanged ends of the valve in the pipe flange.
Butterfly structures and the problems in the course of
Currently, the butterfly as a piping system used to implement on-off and flow control components, has been in the petroleum, chemical, metallurgy, water and electricity , and many other fields has been very widely used . In the well-known butterfly valve technology , the sealing forms enclosed structure, sealing material for rubber , PTFE and so on. Restrictions due to structural features , suited high temperature, high pressure and corrosion resistance, abrasion resistance and other industries. Present a more advanced butterfly valve is a three eccentricity metal hard seal butterfly valve, valve and seat components for the piece , seat sealing surface layer welding temperature, corrosion resistant alloys. Multilayer soft stacked ring fixed to the valve plate, this butterfly valve in comparison with the conventional high temperature , easy operation, open and close without friction, closed with the transmission of the torque increases to compensate for sealing , improved valve sealing performance and durability advantages . However, this butterfly is still in the course of the following problems: one , because soft and hard stacked ring fixed in the valve plate, when the valve plate normally open state media, the formation of a positive sealing surface erosion, sheet metal sandwich the soft sealing tape subject to erosion , direct impact on seal performance. Second, by the structural constraints of the structure do not meet the following diameter DN200 valves, because the overall structure of the valve plate is too thick, large flow resistance . Third, because the principle of three eccentric structure , the sealing surface of the valve plate seal between the valve seat is on the transmission of torque to the valve plate is pressed against the valve seat . Positive flow state, the higher the pressure medium sealed tight squeeze . When the flow channel upstream medium with media pressure valve plate and valve seat pressure between the units is less than the medium pressure, the seal started to leak . High-performance three eccentric hard sealing butterfly valve , wherein : said valve seat ring seal ring by a soft T-shaped multilayer stainless steel sheet on both sides . Valve plate and valve seat sealing surface for the oblique cone structure , oblique cone surface of the valve plate welding temperature, corrosion resistant alloy material ; adjusting ring plate fixed on the spring between the platen adjustment screw assembly structures. This structure effectively compensate for tolerances between the sleeve and the valve stem in the medium band and elastic deformation under pressure to solve the two-way valve in the transmission medium of exchange sealing problems exist in the process . Use of soft T seals on both sides of multilayer stainless steel sheet , with a metal seal and soft seal the dual advantages of both low and high temperatures, both with zero leakage sealing performance . Test proved positive Chi flow state ( medium flow direction and the disc rotation in the same direction ) , the sealing surface pressure is the transmission of torque and media pressure on the valve plate produced by interaction . Forward medium pressure increases, the valve plate oblique cone surface and the valve seat sealing surface squeezed more tightly , sealing the better . When the counter state, the valve plate and valve seat seal between the drive torque to the valve plate is pressed against the valve seat . With reverse media pressure , the valve plate and valve seat pressure between the units is less than the medium pressure, adjusting ring spring contained in the subject after the deformation energy stored in compensation valve plate and valve seat sealing surface of the clamping pressure play the role of automatic compensation . Therefore, the utility model, unlike the existing technologies, as the valve plate mounting hardware multi ring, but directly mounted on the valve body , the middle seat in the platen and an additional adjustment ring is a very good way to two-way seal . It can replace the valve, closing valves and ball valves.
Butterfly valve for the occasion
Butterfly valves for flow control . Since valve pressure loss in the pipeline is relatively large , which is about three times the gate , so the choice of valve when the piping system should be fully considered by the pressure loss should also be considered closed when the disc to withstand rugged medium pressure pipeline sex . In addition, you must consider the material under high temperature exposure resilient seat operating temperature limits. Butterfly valve length and overall height of the structure is small, open and close fast, and has a good fluid control features , butterfly structure principle most suitable for the production of large diameter valves . When asked for the flow control valve is used , the most important is the correct choice of the size and type of valve , so that it can properly work efficiently . Butterfly valve
Typically, the throttle control and regulate the media in the mud , requiring a short length of the structure , opening and closing speed ( 1/ 4 turn ) . Low pressure cut-off ( pressure difference ) , recommended use butterfly valves. In dual position adjustment , necking ground channel, low noise , cavitation and gasification phenomenon , a small amount of leakage to the atmosphere , abrasive media, you can use butterfly valves. In exceptional working conditions throttle , or require strict sealing , or badly worn , low temperature ( cryogenic ) and other working conditions when using the butterfly , use a specially designed metal sealing tape adjustment device to three eccentric or double eccentric dedicated butterfly valve. Butterfly valve for applications that require up completely sealed , gas leakage test is zero, higher life expectancy , the working temperature of -10 degrees to 200 degrees of fresh water, sewage, water , salt water, steam , gas, food , pharmaceuticals , oil and various kinds of acid and other pipeline. Soft seal butterfly valve for opening and closing the ventilation and dust piping bidirectional adjustment, widely used in metallurgy , light industry , electric power , petrochemical and gas pipeline systems and waterways . Metal to metal wire sealing double eccentric butterfly valve suitable for urban heating, gas , water and other gas , oil, acid and other piping, as scaling and throttling devices. Metal to metal face seal butterfly valve except as a large pressure swing adsorption (PSA) process control valves gas separation device used , but also widely used in petroleum , petrochemical , chemical, metallurgy , electric power and other fields, when the gate valve, globe valve good alternative products.
