English
Español 
Português 
русский 
Français 
日本語 
Deutsch 
tiếng Việt 
Italiano 
Nederlands 
ภาษาไทย 
Polski 
한국어 
Svenska 
magyar 
Malay 
বাংলা ভাষার 
Dansk 
Suomi 
हिन्दी 
Pilipino 
Türkçe 
Gaeilge 
العربية 
Indonesia 
Norsk 
تمل 
český 
ελληνικά 
український 
Javanese 
فارسی 
தமிழ் 
తెలుగు 
नेपाली 
Burmese 
български 
ລາວ 
Latine 
Қазақша 
Euskal 
Azərbaycan 
Slovenský jazyk 
Македонски 
Lietuvos 
Eesti Keel 
Română 
Slovenski 
मराठी 
Srpski језик
The difference between centerline butterfly valve single eccentric double eccentric triple eccentric butterfly valve
2021-11-13
The difference between the single eccentric double eccentric triple eccentric butterfly valve of the center line butterfly valve is introduced as follows:
1. Centerline butterfly valve (concentric butterfly valve)
The structural feature of the centerline butterfly valve is that the shaft center of the valve stem, the center of the butterfly plate, and the center of the body are in the same position. The structure is simple and the manufacturing is convenient. Common rubber-lined butterfly valves belong to this category. The disadvantage is that the butterfly plate and the valve seat are always in a state of squeezing and scratching, with a large resistance distance and rapid wear. In order to overcome squeezing, scratching, and to ensure the sealing performance, the valve seat basically uses elastic materials such as rubber or polytetrafluoroethylene, but it is also limited by the temperature in the use of the sealing material. This is why traditionally people think that butterfly valves are not resistant. The cause of the high temperature.
The structural feature of the single eccentric butterfly valve is that the shaft center of the valve stem deviates from the center of the butterfly plate, so that the lower end of the butterfly plate no longer becomes the rotation axis, disperses, reduces the excessive extrusion between the upper end of the butterfly plate and the valve seat, and solves the concentric butterfly valve. The squeeze problem of the butterfly plate and the valve seat. However, because the single eccentric structure does not disappear during the entire opening and closing process of the valve, the scratch between the butterfly plate and the valve seat has not disappeared.
3. Double eccentric butterfly valve
The double eccentric butterfly valve is further improved on the basis of the single eccentric butterfly valve, and its application is also very extensive. Its structural feature is that the axis of the valve stem deviates from the center of the butterfly plate and the center of the body. The double eccentric effect enables the butterfly plate to be released from the valve seat immediately after the valve is opened, which greatly eliminates unnecessary excessive extrusion and scratching of the butterfly plate and the valve seat, reduces the opening resistance, reduces wear and improves The life of the valve seat is improved. The scraping is greatly reduced, and at the same time, the double eccentric butterfly valve can also use a metal seat, which improves the application of the butterfly valve in the high temperature field. However, because the sealing principle is a positional sealing structure, that is, the sealing surface of the butterfly plate and the valve seat is in line contact, the elastic deformation caused by the butterfly plate squeezing the valve seat produces a sealing effect, so the closed position is very demanding (especially metal Valve seat), low pressure bearing capacity, which is why traditionally people think that butterfly valves are not resistant to high pressure and have large leakage.
Structural characteristics of double eccentric butterfly valve
To withstand high temperatures, hard seals must be used, but the amount of leakage is large; for zero leakage, soft seals must be used, but they are not resistant to high temperatures. In order to overcome the contradiction of the double eccentric butterfly valve, the butterfly valve was eccentric for the third time. Its structural feature is that while the double eccentric valve stem axis position is eccentric, the conical axis of the butterfly plate sealing surface is skewed to the cylinder axis of the body, that is to say, after the third eccentricity, the sealing section of the butterfly plate is not Furthermore, it is a true circle, but an ellipse, and the shape of the sealing surface is therefore asymmetric, one side is inclined to the center line of the body, and the other side is parallel to the center line of the body. A major feature of this third eccentricity is that the sealing structure is fundamentally changed. It is no longer a positional seal, but a torsion seal, that is, it does not rely on the elastic deformation of the valve seat, but completely depends on the contact surface pressure of the valve seat. The sealing effect, therefore, solves the problem of zero leakage of the metal valve seat in one fell swoop, and because the contact surface pressure is proportional to the medium pressure, the high pressure and high temperature resistance can also be easily solved.
1. Centerline butterfly valve (concentric butterfly valve)
The structural feature of the centerline butterfly valve is that the shaft center of the valve stem, the center of the butterfly plate, and the center of the body are in the same position. The structure is simple and the manufacturing is convenient. Common rubber-lined butterfly valves belong to this category. The disadvantage is that the butterfly plate and the valve seat are always in a state of squeezing and scratching, with a large resistance distance and rapid wear. In order to overcome squeezing, scratching, and to ensure the sealing performance, the valve seat basically uses elastic materials such as rubber or polytetrafluoroethylene, but it is also limited by the temperature in the use of the sealing material. This is why traditionally people think that butterfly valves are not resistant. The cause of the high temperature.
The structural feature of the single eccentric butterfly valve is that the shaft center of the valve stem deviates from the center of the butterfly plate, so that the lower end of the butterfly plate no longer becomes the rotation axis, disperses, reduces the excessive extrusion between the upper end of the butterfly plate and the valve seat, and solves the concentric butterfly valve. The squeeze problem of the butterfly plate and the valve seat. However, because the single eccentric structure does not disappear during the entire opening and closing process of the valve, the scratch between the butterfly plate and the valve seat has not disappeared.
3. Double eccentric butterfly valve
The double eccentric butterfly valve is further improved on the basis of the single eccentric butterfly valve, and its application is also very extensive. Its structural feature is that the axis of the valve stem deviates from the center of the butterfly plate and the center of the body. The double eccentric effect enables the butterfly plate to be released from the valve seat immediately after the valve is opened, which greatly eliminates unnecessary excessive extrusion and scratching of the butterfly plate and the valve seat, reduces the opening resistance, reduces wear and improves The life of the valve seat is improved. The scraping is greatly reduced, and at the same time, the double eccentric butterfly valve can also use a metal seat, which improves the application of the butterfly valve in the high temperature field. However, because the sealing principle is a positional sealing structure, that is, the sealing surface of the butterfly plate and the valve seat is in line contact, the elastic deformation caused by the butterfly plate squeezing the valve seat produces a sealing effect, so the closed position is very demanding (especially metal Valve seat), low pressure bearing capacity, which is why traditionally people think that butterfly valves are not resistant to high pressure and have large leakage.
Structural characteristics of double eccentric butterfly valve
To withstand high temperatures, hard seals must be used, but the amount of leakage is large; for zero leakage, soft seals must be used, but they are not resistant to high temperatures. In order to overcome the contradiction of the double eccentric butterfly valve, the butterfly valve was eccentric for the third time. Its structural feature is that while the double eccentric valve stem axis position is eccentric, the conical axis of the butterfly plate sealing surface is skewed to the cylinder axis of the body, that is to say, after the third eccentricity, the sealing section of the butterfly plate is not Furthermore, it is a true circle, but an ellipse, and the shape of the sealing surface is therefore asymmetric, one side is inclined to the center line of the body, and the other side is parallel to the center line of the body. A major feature of this third eccentricity is that the sealing structure is fundamentally changed. It is no longer a positional seal, but a torsion seal, that is, it does not rely on the elastic deformation of the valve seat, but completely depends on the contact surface pressure of the valve seat. The sealing effect, therefore, solves the problem of zero leakage of the metal valve seat in one fell swoop, and because the contact surface pressure is proportional to the medium pressure, the high pressure and high temperature resistance can also be easily solved.
We use cookies to offer you a better browsing experience, analyze site traffic and personalize content. By using this site, you agree to our use of cookies.
Privacy Policy