Structural differences and operating differences between upward-opening discharge valves and downward-opening discharge valves

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Those working in the valve industry often struggle to understand the differences between upward-opening discharge valves and downward-opening discharge valves. Valve Technology Network has analyzed the applicability, structure, dimensions, torque, and other aspects of these two types of valves, comparing their features: Applicability – Discharge valves are primarily used for discharging materials from the bottom of storage tanks, reactors, and other containers. They are connected to the equipment via flanges or butt welding and are located at the bottom of the container, which helps to eliminate any residue of the process medium that might remain at the container’s outlet. Depending on the actual requirements, they are made in either an upper-opening or lower-opening design ； The upward discharge method is used for discharging from reaction vessels equipped with agitators and discharge valves ； The downward-opening discharge valve is used for discharging material from the reaction vessel of frame-type anchor agitators. Structural differences and differences in opening/closing torque: In the upward-opening discharge valve, the valve disc moves upward to open the valve; when opening, the valve must overcome the force exerted by the medium, and thus the opening torque is greater than the closing torque. In the downward-opening discharge valve, the valve disc (plunger) moves downward to open the valve; the direction of this movement is the same as that of the force exerted by the medium, which results in a lower opening torque compared to the closing torque. Difference in opening and closing stroke: Due to the difference in opening and closing stroke, the installation dimensions vary; upward-opening discharge valves and downward-opening discharge valves have a shorter opening and closing stroke and thus a lower installation height. Piston-type discharge valves are divided into two structural types based on the piston structure and its mode of movement: the lifting rod type and the rotating rod type. The lifting rod type requires more installation space, but it allows for an intuitive determination of the valve’s open/closed state and position based on the piston’s movement and location. The rotary rod design results in the lowest installation height; during the opening and closing process, the plunger only moves in a rotational manner. It relies on an indicator that shows the opening and closing position to determine whether the valve is open or closed and its current position. This article is reprinted from Gongke.com