I have a question regarding high-temperature butterfly valves
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For high-temperature butterfly valves, considering the effect of thermal expansion, must the sealing surfaces be made of the same material? ? ? I believe that only when the materials are the same and have the same coefficient of expansion can sealing be ensured at both high temperatures and normal temperatures
Should the material of the butterfly valve mentioned by the poster be the same as that of the sealing pair? Regardless of the material of the valve body, the materials of the sealing surface and the sealing seat should not be the same. In order to achieve sealing, a certain sealing pressure is required; moreover, there should be a certain difference in hardness between the materials of the two components that come into contact for sealing, so as to achieve a better sealing effect. This is why a sealing material is welded on the sealing surface. We generally select the materials for various components based on requirements such as temperature, medium, and operating conditions, aiming to meet these requirements while also taking cost considerations into account. As for the consideration of the expansion coefficient, for high-temperature butterfly valves, I personally think that the elastic sealing structure needs to be given special attention. The above are just my personal opinions; I’m not sure if they’re correct. Please advise!
High-temperature butterfly valves are generally metal-sealed butterfly valves, with triple-eccentric butterfly valves being the most common type. The shapes of sealing pairs vary, and even materials of the same type can deform differently; therefore, it is not necessary for them to be made of the same material. Consider the temperature range, medium (corrosion, particulates, etc.), whether it is a one-way or two-way seal, as well as good cost-performance.
I agree with what was said on the 3rd floor: it is difficult to achieve an ideal sealing effect using the same material. When considering high-temperature butterfly valves, factors such as the material’s high-temperature creep, as well as its relationship with the sealing pressure, play a crucial role in addition to the expansion coefficient.
High-temperature butterfly valves are not easy to manufacture, and their sealing performance is generally inadequate. The position of the valve sleeve must take into account cooling or expansion to absorb forces; otherwise, leakage is guaranteed
In that case, the calculation for high-temperature butterfly valves is quite complex. The required processing precision is also very high. At 600 degrees, what materials do people usually choose for (valve body, valve disc, sealing pair)? ? ?