how do knife gate valves work

- Mar 28, 2019-

how do knife gate valves work



Knife gate valve is also called knife gate valve, knife gate valve, slurry valve and mud valve. Its opening and closing parts are gate plate. The movement direction of gate plate is perpendicular to the direction of fluid. The medium is cut off by the knife-edge gate which can cut the fibre material. The gate plate has two sealing faces. The two sealing surfaces of the most commonly used mode gate valve form wedge shape and wedge angle, which vary with the valve parameters, usually are 5 degrees, and wedge knife type. The gate of the gate valve can be made into a whole, called rigid gate, or can be made into a gate which can produce slight deformation to improve its technicality and make up for the deviation caused by the angle of sealing surface in the process of processing. This kind of gate is called elastic gate. In fact, there is no chamber in the valve body. The gate rises and falls in the side guide groove, and is pressed on the seat by the bottom lug. If high medium sealing is needed, O-shaped sealing seat can be used to achieve bidirectional sealing. Knife gate valve has less installation space, low working pressure, not easy to accumulate debris, low price.


When the knife gate valve closes, the sealing surface can be sealed only by the medium pressure, that is to say, the sealing surface of the gate plate is pressed to the seat on the other side to ensure the sealing surface. This is self-sealing. Most gate valves are sealed by force, that is, when the valve closes, the gate plate is forced to the seat by external force to ensure the sealing surface. Valves of this type shall generally be installed vertically in pipes.


Driving mode of knife gate valve: manual, sprocket, electric, pneumatic, hydraulic, bevel gear, electronically controlled hydraulic and pneumatic. Knife gate valve shape: open rod, dark rod two kinds. Material of knife gate valve: cast iron, cast steel, carbon steel, stainless steel, lining fluorine, etc.


Knife gate valve seal: hard seal, soft seal, one-sided seal, double-sided seal and other material seal.


Ultra-thin knife gate valve with its small size, small flow resistance, light weight, easy installation, easy disassembly and other advantages thoroughly solved the common gate valve, flat gate valve, ball valve, globe valve, control valve, butterfly valve and other valve flow resistance, heavy weight, difficult installation, large area and other difficult problems. After the emergence of knife gate valves, a large number of universal cut-off valves and adjusting valves have been replaced. The world's largest use of knife gate valves is in the United States and Japan.


The application range of knife gate valve is:

1. Mining, coal washing, iron and steel industry - used for coal washing pipelines, slurry filter pipelines, ash discharge pipelines, etc.

2. Purification device - used for wastewater, slurry, sewage and clarified water with suspended matter;

3. Paper industry - for any concentration of pulp and water mixture;

4. Ash removal in power plants - for ash slurry 


knife gate valve