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A gate valve is a valve in which the closing element (gate) moves vertically along the axis of the passage; it is primarily used in pipelines to shut off the flow of medium, that is, to operate in either fully open or fully closed position. Generally, gate valves cannot be used to regulate flow. It can be used in low-temperature and low-pressure conditions as well as in high-temperature and high-pressure conditions, and it can be adapted to different valve materials. However, gate valves are generally not used in pipelines for transporting media such as slurry. Advantages: ① Low fluid resistance ； ②The torque required to open and close is low ； ③It can be used in ring piping systems where the medium flows in both directions; in other words, the flow direction of the medium is not restricted ； ④When fully open, the sealing surface is subject to less erosion by the working medium compared to a globe valve ； ⑤Its structural design is relatively simple, and it is easy to manufacture ； ⑥The structural length is relatively short. Disadvantages: ① It has large external dimensions and opening height, requiring a substantial amount of space for installation ； ②During the opening and closing process, relative friction occurs between the sealing surfaces, resulting in significant wear; in addition, high temperatures can easily cause scuffing ； ③Generally, gate valves have two sealing surfaces, which adds some difficulty to processing, grinding, and maintenance ； ④The opening and closing time is long. A butterfly valve is a type of valve that uses a disc-shaped operating element to rotate back and forth by about 90° in order to open, close, and regulate the flow of fluid. Advantages: ① Simple structure, small size, light weight, and low material consumption; particularly suitable for large-diameter valves ； ②Rapid opening and closing, low flow resistance coefficient ； ③It can be used in media containing suspended solid particles, and depending on the strength of the sealing surface, it can also be used for powdered and granular media. It can be used for two-way opening, closing, and adjustment in ventilation and dust removal pipelines, and is widely applied to gas pipes and water pipelines in metallurgy, light industry, power, and petrochemical systems. Disadvantages: ① The flow rate adjustment range is limited; when it is set to 30%, the flow rate already exceeds 95%. ②Due to the structure of butterfly valves and the limitations of their sealing materials, they are not suitable for use in high-temperature and high-pressure pipeline systems. The normal operating temperature is below 300°C, and the pressure rating is below PN40 (6–40). ③Its sealing performance is inferior to that of ball valves and globe valves, so it is used in applications where high sealing requirements are not necessary.