Knife gate valve is a valve whose gate plate and valve seat are always in close contact and sealed. Its principle is that there is a circular opening with a diameter on the gate plate. The opening and closing of the gate plate make the circular opening on the gate plate completely separate from and coincide with the diameter. The advantage of this valve is that the valve body diameter has no groove, the medium will not jam, and it has the flow characteristics of full diameter. Its sealing structure can be divided into soft sealing and hard sealing structures. The penetrating knife gate valve is characterized by structure, good processability, compact structure, etc. The sealing valve seat is designed as a movable structure, with wear prevention and automatic compensation functions, so its service life is longer. During the closing and opening process, the valve seat moves closely with the gate, which makes the opening and closing force of the valve stable and has the characteristics of cutting off the medium.