The knife valve is a type of valve designed for on/off control of fluids, especially viscous or containing solids. It features a sharp-edged blade that cuts through the flow when closed, ensuring a tight seal. The valve operates with a linear motion, either manually or automatically. It is commonly used in applications like wastewater and sludge handling. Knife valves are durable, simple to maintain, and effective for controlling thick or particulate-laden fluids.