The gate valve refers to the valve whose closing member (gate) moves along the vertical direction of the channel axis. It is mainly used to cut off the medium on the pipeline, that is, fully open or fully closed. In general, gate valves cannot be used to regulate flow. It can be applied to low temperature pressure or high temperature and high pressure, and can be used according to different materials of the valve. However, gate valves are generally not used in pipelines that transport mud and other media. The advantages of the gate valve are that the fluid resistance is small; the torque required for opening and closing is small; it can be used in the ring network pipeline where the medium flows in two directions, that is to say, the flow direction of the medium is not restricted; when it is fully opened, the sealing surface is affected by the working medium. The erosion is smaller than that of the globe valve; the shape and structure are relatively simple, and the manufacturing process is better; the structure length is relatively short. Disadvantages include that the overall size and opening height are large, and the space required for installation is also large; during the opening and closing process, the sealing surface is relatively rubbed, the friction loss is large, and even scratches are easily caused at high temperatures; general gate valves are There are two sealing surfaces, adding some difficulties to machining, grinding and maintenance; long opening and closing time.
Butterfly valve is a kind of valve that uses a disc type opening and closing member to reciprocate about 90° to open, close and adjust the fluid channel. Advantages of butterfly valve: simple structure, small size, light weight, low consumables, not used in large-diameter valves; rapid opening and closing, small flow resistance; can be used for media with suspended solid particles, and can also be used for powder according to the strength of the sealing surface. and granular media. It can be used for two-way opening and closing and adjustment of ventilation and dust removal pipelines, and is widely used in gas pipelines and waterways of metallurgy, light industry, electric power, and petrochemical systems. Disadvantages of butterfly valve: The flow adjustment range is not large. When the opening reaches 30%, the flow rate is nearly 95%; due to the limitation of the structure and sealing material of the butterfly valve, it is not suitable for high temperature and high pressure pipeline system. The general working temperature is below 300°C and below PN40; the sealing performance is poorer than that of ball valves and globe valves, so it is used in places where sealing requirements are not very high.
