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Metal seal butterfly valve means that both sides of the seal pair are made of metal material or other hard materials. The sealing performance is poor, but it is resistant to high temperature, abrasion and good mechanical properties. Such as: steel + steel; steel + copper; steel + graphite; steel + alloy steel. The steel here may also be cast iron, cast steel, alloy steel or alloys for surfacing an...
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Sealing is to prevent leakage, so the principle of valve sealing is also studied from leak prevention. There are two main factors that cause leakage. One is the most important factor affecting the sealing performance, that is, there is a gap between the sealing pairs, and the other is the pressure difference between the two sides of the sealing pair. The principle of valve sealing is also analyzed...
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(1) Soft sealing material A. Nitrile rubber (NBR). Nitrile rubber has excellent oil resistance; heat resistance is superior to natural rubber and styrene-butadiene rubber; air tightness and water resistance are better. Nitrile rubber can be divided into butyronitrile-18, butyronitrile-26 and butyronitrile-40. Nitrile rubber is suitable for petroleum products with a temperature of -60 ° C ~ +120 ° ...
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Before we select an appropriate ball valve, there are many factors we need to take into consideration. Seat type is one of important perspectives. Soft Seated Ball Valve The seat ring in contact with the ball part is made of soft material, such as PTFE, RPTFE, Nylon, Devlon, Peek and so on. For floating ball valve, there is only one soft seat ring for one side seat. But for trunnion ball valve, th...
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The factors affecting the sealing performance of the c are as below: A. sealing surface quality; b. sealing surface width; c. pressure difference; d. sealing surface material and its processing state; e. medium properties; f. surface hydrophilicity; g. the existence of sealing oil film ; h. the solid and structural characteristics of the closure. 1) Influence of sealing surface quality on valve se...
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Most of ball valves own the sealant injection system. In this article, we will explain why ball valve is installed with sealant injection fittings. Generally speaking, each ball valve has two sealant injection fittings. One is located at the stem area and the other seat area, like the picture shown below. The sealant injection system of ball valve plays a part as the emergency sealing or backup se...
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