The operating pressure is 1.2 MPa, the diameter is DN350, and the medium is corrosive; if a butterfly valve is to be used,
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What should be chosen for the sealing surface to ensure no leakage during use, for the pump outlet valve?
Butterfly valves with soft seals can be chosen; the material depends on the specific medium
First, pressure is combined with temperature, the type and degree of medium corrosion, to select the valve material and butterfly valve type (centerline or eccentric, whether dual sealing is required, etc.)； Then, based on the temperature-pressure ratings corresponding to the specific material of the valve, the nominal pressure class of the valve is determined ； It is relatively more difficult to ensure the sealing performance of butterfly valves; under the permissible conditions, as mentioned on the second floor, soft-seal types offer better sealing performance ； Additionally, the quality of butterfly valves is also closely related to the manufacturer chosen. The type of sealing surface isn’t particularly important; for media that are not extremely hazardous and at a pressure of 1.2 Mpa, an RF surface is sufficient.
Just pressure and corrosiveness aren’t enough; you also need to consider the temperature of the medium, the properties of the corrosive liquid, flow rate, and so on
Temperature, medium, pressure rating, whether it is at a constant temperature or with significant temperature variations, etc
For low pressure and low temperature conditions, fluorine-lined butterfly valves are recommended; for high pressure and high temperature conditions, metal hard-sealed butterfly valves with cemented carbide coatings are advised.
Choose a gate valve. For butterfly valves, the flange connection type should be chosen. An RF flange will do.
Valve gates are a better choice for such an important location as the pump outlet, as the structure of butterfly valves itself cannot ensure leak-free operation