The concentric butterfly valve is characterized by the alignment of the stem axis, the butterfly disc center, and the body center. This design offers a simple structure, making it easy to manufacture. A common example is the rubber-lined butterfly valve. However, one major drawback is that the disc and seat are constantly in a squeezed and scraped condition, leading to high resistance and rapid wear. To address this issue and ensure good sealing performance, the seat is typically made from elastic materials like rubber or PTFE. But due to temperature limitations, traditional concentric butterfly valves are not suitable for high-temperature applications.
To overcome the problem of excessive squeezing and scraping, the single eccentric butterfly valve was developed. In this design, the stem axis is offset from the center of the butterfly disc, which means the disc no longer rotates around the same axis as the seat. This reduces the over-squeeze between the disc and seat. However, during the entire opening and closing process, some scraping still occurs, and its application range is similar to that of the concentric type, so it's not widely used.
The double eccentric butterfly valve represents a further improvement over the single eccentric model. It features an additional eccentricity, with both the stem axis and the disc center being offset from the body center. This double eccentric design allows the disc to quickly separate from the seat when opening, significantly reducing unnecessary friction and wear. As a result, the valve operates more smoothly, lasts longer, and can even use metal seats, making it suitable for high-temperature applications. However, because the sealing mechanism relies on line contact and elastic deformation, the pressure capacity is relatively low, and leakage can be an issue, which is why traditional butterfly valves are often seen as less reliable in high-pressure environments.
To address the conflict between high-temperature performance and zero leakage, the three eccentric butterfly valve was introduced. This design takes the double eccentric concept a step further by introducing a third eccentricity. The sealing surface of the disc is conically offset from the body’s axis, creating an oval-shaped seal rather than a rectangular one. This asymmetrical design, combined with a tilted body centerline, allows the valve to achieve a torque-based sealing mechanism instead of relying solely on elastic deformation. As a result, it can provide a tight seal without leakage while also withstanding high temperatures and pressures. This innovation effectively solves the long-standing challenges of traditional butterfly valves, making it a more versatile and reliable option in various industrial applications.
Torque Converter
What is the difference between a SDLG torque converter and a gearbox?
The torque converter is part of the automatic transmission (AT).
The torque converter consists of a pump wheel, a turbine wheel and a guide wheel. It is installed between the Engine and the transmission and uses hydraulic oil (ATF) as the working medium to transmit torque, change torque, speed change and clutch.
The pump wheel and turbine of the torque converter form a closed working chamber that allows the liquid to circulate. The pump wheel is installed on the input shaft, and the turbine is installed on the output shaft. When the power machine (internal combustion engine, electric motor, etc.) drives the input shaft to rotate, the liquid is thrown out by the centrifugal pump wheel. After this high-speed liquid enters the turbine, it drives the turbine to rotate, and transfers the energy obtained from the pump wheel to the output shaft. Finally, the liquid returns to the pump wheel, forming a cyclical flow. The torque converter transfers torque by generating changes in momentum moment by the interaction of the liquid with the impeller and turbine blades. Its output torque is equal to the input torque minus the friction torque, so its output torque is always less than the input torque. The input shaft and output shaft of the torque converter rely on liquid connection, and there is no rigid connection between the working components.(Sdlg Loader Torque Converter,Hydraulic Converter Parts,Torque Converter,Low Speed Turbine Set)
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