Oct.23.2025
This passage provides insights into three types of knife gate valves—Manual (rising stem), Pneumatic, and Electric. The manual valve utilizes a handwheel for gate control, suitable for horizontal and tilted installations. The pneumatic version, featuring double- and single-acting cylinders, is designed for rapid cutting or opening in high-pressure scenarios. Electric knife gate valves, powered by multi-turn electric actuators, offer remote control capabilities and are applicable in diverse settings, emphasizing strict adherence to wiring guidelines.
Manual (rising stem) knife gate valve:
The manual knife gate valve uses a manual handwheel to open and close the gate. A clockwise operation opens the valve and counterclockwise operation closes the valve. This knife type gate valve is suitable for horizontal installation and tilted installation.
Pneumatic knife gate valve:
Pneumatic knife gate valve is a relatively complex automatic control instrument, which is composed of a variety of pneumatic components and valve bodies. It is mostly used in situations that require quick cutting or opening (the supply air pressure under working conditions needs to reach 4Mpa).
Double-acting cylinder: two-position control of gate opening and closing
Single-acting cylinder: When the circuit and gas line are cut off or malfunctioned, the gate automatically opens or closes (i.e. normally closed or normally open). The lower air inlet of the cylinder (near the valve) is the opening valve, and the upper air inlet of the cylinder is the closing valve.
Electric knife gate valve
Knife gate valves are mostly used with multi-turn electric actuators (electrical installation needs to be transferred to a control box for control). The operator can control the valve remotely in the control room, manually operate it on site, or cooperate with a computer to automatically control it. Electrical installation must strictly refer to the wiring diagram and instructions for wiring to prevent accidents caused by wiring errors.
Application:
1. Sewage Treatment: Pneumatic knife gate valves are often used in sewage treatment plants and sewage pipeline systems to control sewage flow. Knife gate valves are designed to handle fluids containing solid particles.
2. Paper Industry: usually used to control the flow of pulp and wastewater. They can handle high concentrations of suspended solids and help maintain process stability.
3. Chemical Industry: usually used to handle chemicals with corrosive or harmful properties. Their sealing properties and corrosion resistance make them a suitable choice.
4. Mining Industry: Pneumatic knife gate valves are used to control the flow of ore, tailings and slurries, especially in mining and smelting processes.
5. Slag Treatment: In the steel manufacturing and smelting process, pneumatic knife gate valves are used to control the flow and discharge of slag.
