Differentiation between knife gate valve and common gate valve

Knife gate valve can only be used to cut off rather than to throttle, and gate valve can throttle or switch. Compared with ordinary gate valve, knife gate valve has simple structure, small size, flexible operation, easy installation, and is suitable for medium with high consistency and solid particles. The full-bore knife gate valve design enables the valve to be used under the condition of dirt medium, and the replaceable valve seat and packing make the maintenance of the valve simple. Although the performance is good, the price of knife gate valve is generally higher than that of gate valve.

The difference between the use range of knife gate valve and ordinary gate valve

Knife gate valve is applicable to viscous particles and is often used in beverage, paper making, pulp industry, industrial sewage, urban sewage treatment, chemical plant, bulk material transportation and fly ash treatment industries. Gate valves are generally used in chemical, metallurgical, power station, mining, pharmaceutical, boiler, tobacco, hotel, construction, textile and other industries.

Knife gate valve is also called knife gate valve, knife gate valve, slurry valve and mud valve. Its opening and closing parts are the gate. The movement direction of the gate is perpendicular to the direction of the fluid. The media is cut off by the blade gate which can cut the fiber material. The gate has two sealing surfaces. The two sealing surfaces of the commonly used mode gate valve form a wedge. The wedge angle varies with the valve parameters, usually 5 °. The gate of the wedge knife gate valve can be made into a whole, It is called rigid ram; It can also be made into a ram that can produce a small amount of deformation to improve its processability and make up for the deviation of the sealing surface angle in the process of processing. This kind of ram is called elastic ram.

In fact, there is no chamber in the valve body. The gate rises and falls in the side guide groove and is tightly pressed on the valve seat by the lug at the bottom. If it is necessary to achieve high medium tightness, the O-ring seal valve seat can be selected to achieve two-way sealing. Knife gate valve has a small installation space, low working pressure, is not easy to accumulate debris, and low price.

When the knife-type gate valve is closed, the sealing surface can only rely on the medium pressure to seal, that is, the sealing surface of the gate plate is pressed against the valve seat on the other side by the medium pressure to ensure the sealing of the sealing surface, which is self-sealing. Most gate valves adopt forced sealing, that is, when the valve is closed, the gate plate shall be forced to the valve seat by external force to ensure the sealing of the sealing surface.

The gate valve is suitable for use in mud and medium pipes containing fiber, and its knife-shaped gate can cut off the fiber material in the medium; It is widely used in the pipeline for conveying coal slurry, ore slurry and paper pulp.