Structure and Working Principle of Pneumatic Knife Gate Valve

Structure and Working Principle of Pneumatic Knife Gate Valve

Pneumatic knife gate valve is a valve controlled by a pneumatic actuator to achieve opening and closing. It can be divided into two parts: the upper part is the pneumatic actuator, and the lower part is the valve.

The pneumatic knife gate valve can accomplish two-position action control and signal output for opening and closing, as well as automatic control for continuous action, through the use of accessories such as solenoid valves and proximity switches.

Knife Gate Valve Structure

The opening and closing element of a knife gate valve is the gate plate, and the movement direction of the gate plate is perpendicular to the fluid flow direction. When the knife gate valve is closed, the sealing surface can be sealed solely by medium pressure, meaning the medium pressure presses the sealing surface of the gate plate against the valve seat on the opposite side to ensure sealing. This is called self-sealing.

Most knife gate valves use forced sealing, meaning when the valve is closed, external force is required to press the gate plate against the valve seat to ensure the sealing performance of the sealing surface.

Knife Gate Valve Characteristics

Knife gate valves can only be fully opened or fully closed and cannot be used for regulation or throttling. Pneumatic knife gate valves feature a simple and compact structure, convenient design, light weight and material savings, reliable sealing, light and flexible operation, small size, smooth flow passage, low flow resistance, light weight, easy installation, and easy disassembly. They can operate normally under working pressures of 1.0MPa to 2.5MPa and operating temperatures ranging from -29°C to 650°C.

The gate plate of the knife gate valve has a shearing function, which can scrape away adhered materials on the sealing surface and automatically remove debris. The stainless steel gate plate can prevent sealing leakage caused by corrosion.