Is the selection of the sealing type for the control butterfly valve also based on temperature, just like in the case of ball valves?
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I remember a senior once saying that control valves (gate valves) usually have metal seals, because they operate at a specific opening degree; as a result, the erosive effect of the flow on the valve core is much greater than in ball valves, which is why metal seals are necessary. But recently, while looking at control butterfly valves used in 2 projects (low temperature and pressure, pure medium), I noticed that they all have soft seals. Why is that? Are soft-sealed butterfly valves more resistant to erosion than soft-sealed globe valves?
The reason for the metal seal in globe valves is that they are often used in high-temperature environments. PTFE provides excellent sealing properties and is wear-resistant; it should be used in situations where high temperatures are not present
It is primarily determined based on the operating conditions. In environments with high temperature, high pressure, high flow rates, and corrosivity, a hard seal is advisable. Low temperature, low pressure, low flow rate, and corrosive conditions also allow the use of soft seals.
This post was last edited by yuchenchf on 2015-9-24 at 19:51. For more details, please contact me via the site’s messaging system.
For regulating butterfly valves (used in low temperature and low pressure conditions with pure media), those with soft seals are certainly better than those with hard seals; the design choice is correct.
Sealing primarily takes into account the effects of factors such as the properties of the medium, temperature, and pressure.
The selection should be based on the operating conditions; metal hard seals tend to have a higher leakage rate compared to soft seals
Low pressure, slow flow rate; the medium is clean and there is no erosion. Soft seals are used, providing good sealing performance. The price is slightly lower, but the overall service life is not as good as that of hard seals. When possible, it is better to choose a hard seal; try to use soft seals as little as possible. Soft seals have a short lifespan.
But I see that the normal-temperature control stop valves used in these projects also have metal seals – what’s the reason for that?
Are there any specifications regarding the material choice for valve seats? I’ve searched for a long time but couldn’t find any