Principles and criteria for selecting discharge valves
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Discharge valves can generally be divided into downward-opening and upward-opening types; but in what situations are they suitable for use, and what are their characteristics? Why was this choice made? Those who know please offer guidance!
The discharge valve is primarily used for discharging material from the bottom of reactors, storage tanks, and other containers. It is welded to the bottom of these containers via flanges at its bottom, thereby eliminating the accumulation of process medium at the outlet of the containers. Based on the actual requirements, the discharge valve features a flat-bottom design for the bottom structure; its valve body is V-shaped, and the valve disc is available in two operating modes: lifting and lowering. The interior cavity of the valve body is equipped with wash-resistant and corrosion-resistant sealing rings. At the moment the valve is opened, these rings protect the valve body from being worn away or corroded by the medium. The sealing rings are also subjected to special treatment, resulting in a surface hardness of HRC56-62, which gives them high wear and corrosion resistance. The valve disc seal is clad with cemented carbide on its surface as needed; a linear seal is used for the sealing pair to ensure reliability of the seal and prevent scarring. At the same time, a short-stroke valve disc design is adopted. It is widely used in industries such as chemicals, petroleum, metallurgy, pharmaceuticals, pesticides, dyes, and food processing. Various operating methods, such as manual, pneumatic (spring-return type, double-acting type, with and without a handwheel), electric, hydraulic, gear-driven, etc.
For crystallization inside the tank or the deposition of solid material at the bottom, the upward spreading method is used when fluidity is good, while the downward spreading method is employed in other cases