Gate valve refers to a valve whose closing part (gate) moves along the vertical direction of the channel axis. It is mainly used for cutting off the medium in the pipeline, that is, fully open or fully closing.
Advantages of gate valve:
①The fluid resistance is small;
②The torque required for opening and closing is small;
③It can be used on the ring network pipeline where the medium flows in both directions, that is to say, the flow direction of the medium is not restricted;
④When fully open, the erosion of the sealing surface by the working medium is smaller than that of the stop valve;
⑤The body structure is relatively simple, and the manufacturing process is better;
⑥The structure length is relatively short.
Disadvantages of gate valve:
①The external dimensions and opening height are large, and the installation space required is also large;
②In the process of opening and closing, the sealing surface is relatively rubbed by people, and the abrasion is large, and it is easy to cause abrasion even at high temperature;
③Generally, gate valves have two sealing surfaces, which adds some difficulties to processing, grinding and maintenance;
④Long opening and closing time.
2. The butterfly valve is a 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:
①Simple structure, small size, lightweight, saving consumables, especially used in large-diameter valves;
②Rapid opening and closing, small flow resistance coefficient;
③It can be used for media with suspended solid particles, and it can also be used for powder and granular media depending on the strength of the sealing surface. It can be applied to the two-way opening and closing and adjustment of ventilation and dust removal pipelines and is widely used in gas pipelines and waterways in metallurgy, light industry, electric power, and petrochemical systems.
Disadvantages of butterfly valve:
①The flow rate adjustment range is not large. When the opening reaches 30%, the flow rate will enter more than 95%.
②Due to the limitation of the structure and sealing material of the butterfly valve, it is not suitable for use in high temperature and high-pressure piping systems. The general working temperature is below 300℃ and below PN40 (6-40).
③ Compared with ball valves and globe valves, the sealing performance is poor, so it is used in places where the sealing requirements are not very high.