Plug valve, also known as a manual knife gate valve. A knife gate valve is a valve where the gate and seat are always in tight contact for sealing. Its principle involves a circular opening of the same size as the valve passage on the gate, which opens and closes to completely separate or align with the passage. The advantages of this valve include a valve body passage without grooves, preventing media from being trapped or blocked, and it features full-bore flow characteristics. The sealing structure can be soft or hard. The piercing knife gate valve has precise construction, good workability, and a compact design. The sealing seat is designed as a movable structure with anti-wear and automatic compensation functions, resulting in a longer lifespan.

During the closing and opening process, the valve seat and gate plate remain tightly sealed during movement, ensuring stable opening and closing force and features such as medium cutoff.