The flanges of stainless steel discharge valves with upper and lower expansion types differ. Discharge valves with upper expansion typically have a straight-through diameter, while those with lower expansion generally have a reducing diameter, and the flange at the reaction kettle end is one size larger. What are the differences between upper and lower expansion of stainless steel discharge valves? The valve disc's opening and closing directions are different. As the name suggests, the upper expansion discharge valve opens the valve disc to ascend into the reaction kettle, while the lower expansion discharge valve opens the valve disc to descend into the valve chamber. Due to this reason, the flange level needs to be increased to expand the valve chamber space. The copper nuts differ. The upper expansion discharge gate valve uses copper nuts, while the lower expansion discharge valve uses copper nuts for globe valves. The opening and closing strokes differ, and the installation dimensions are smaller for upper and lower expansion discharge valves. The rotating rod structure has the smallest installation height. During the opening and closing process, the plunger only performs rotational movement, and it relies on an opening and closing position indicator to determine the valve's opening, closing, and position. The opening and closing torque of the upper expansion discharge valve is such that the valve disc moves upward to open the valve. When opening, the valve needs to overcome the medium's force, and the opening torque is greater than the closing torque.

 

The lower-expansion and plunger-type discharge valves open when the valve disc moves downward, and the direction of movement is the same as the force of the medium when it opens, thus resulting in a smaller opening torque compared to the closing torque. Although there are significant differences between the upper-expansion and lower-expansion discharge valves, their common characteristics include a close distance between the valve seat and the end flange, minimal material retention, compact structure, and superior sealing performance. They are used on reaction vessels in the fine chemical, pharmaceutical, and chemical industries, and can also be used for the conveyance of fine and soft particulate media. The use of PPL or M sealing materials provides enhanced wear and temperature resistance, making them the ideal product for discharging in the toothpaste industry and vacuum paste-making vessels.