Knife Valve

Knife valve also known as knife gate valve, slurry valve, mud valve, its opening and closing parts are wedge disc, the movement direction of the wedge disc is perpendicular to the direction of the fluid, and the medium is cut by a blade-shaped wedge disc that can cut fibre material. The wedge disc has two sealing surfaces, the two sealing surfaces of the most commonly used mode gate valve form a wedge shape and a wedge angle varies with the valve parameters, usually 5°, the wedge disc of the wedge knife valve can be made into a whole, called solid wedge; it can also be made into a wedge disc that can produce a small amount of deformation to improve its processability and make up for the deviation of the seal surface angle during the process, this kind of wedge disc is called a flexible disc.

The knife valve body does not actually exist chamber, the wedge disc rise and fall in the side guide groove, and is pressed against the knife gate valve seat by the lug at the bottom, if you need to achieve a high medium sealing, can choose O-ring seal valve seat to achieve two-way sealing. The knife valve has characteristics of smaller installation space, low working pressure, less likely to accumulate debris and are less expensive.

When the knife valve is closed, the sealing surface can only rely on the media pressure to seal, that is, rely on the media pressure to press the sealing surface of wedge disc to the knife gate valve seat on another side to ensure the seal of sealing surface, this is self-sealing, most of the gate valve is used for mandatory sealing, that is, when the knife valve is closed, to rely on external forces to force the wedge disc pressed to the valve seat to ensure the seal of sealing surface. This kind of valve generally should be installed vertically in the pipeline.

Knife valve drive method:

Manual, sprocket, electric, pneumatic, hydraulic, bevel gear, electronically controlled hydraulic and pneumatic-hydraulic drive mode. Knife gate valve shape: open stem, hidden stem two kinds. Knife gate valve material: cast iron, cast steel, carbon steel, fluorine lining and stainless steel knife gate valve.

Knife gate seal:

hard seal, soft seal, single-sided seal, double-sided seal and other material seals.
Ultra-thin knife valve with its small size, small flow resistance, light weight, easy to install, easy to disassemble and other advantages completely solved large flow resistance, large weight, difficult to install, cover an area of large and other difficult problems of the ordinary gate valve, slide gate valve, ball valve, globe valve, control valve, butterfly valve and other types of valve. After the advent of the knife gate valve, a large number of general cut-off valves and control valve have been replaced. Knife gate valve manufacturers are developing quickly worldwide.

Knife valves are used in the following areas:

• Mining, coal washing, iron and steel industry-used for coal washing, filter slurry pipe, ash discharge pipe；
• Purification device – for wastewater, mud, dirt and clarified water with suspended matter；
• Paper industry–for any concentration of pulp and feed water mixture；
• Power station ash removal-for ash residue slurry.