why use a knife gate valve

- May 01, 2020-

why use a knife gate valve

The difference between knife gate valve and common gate valve


The function of knife gate valve is to cut off but not to be used as throttling, and gate valve can be throttling or switching. Compared with the common gate valve, the knife gate valve is simple in structure, small in size, flexible in operation, easy to install and suitable for medium with high consistency and solid particles. The design of full bore knife gate valve enables the valve to be used under the condition of dirty medium, and the replaceable valve seat and packing make the maintenance of the valve simple. Although the performance is better, the price of knife gate valve is generally higher than that of gate valve.


Different application range of knife gate valve and common gate valve

Knife gate valve is suitable for viscous particles, which is often used in beverage, papermaking, 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 known as knife gate valve, knife gate valve, slurry valve and mud valve. Its opening and closing parts are rams. The movement direction of the rams is perpendicular to the direction of the fluid. The media is cut off by knife edge rams that can cut fiber materials. The rams have two sealing surfaces. The two sealing surfaces of the commonly used model gate valve form wedges, and the wedge angle varies with the valve parameters, usually 5 °, The gate of wedge knife gate valve can be made into a whole, which is called rigid gate valve; it can also be made into a gate valve that can produce slight deformation, so as to improve its processability and make up for the deviation of sealing surface angle in the process of processing. This gate valve is called elastic gate valve.

In fact, there is no cavity 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 high medium tightness is required, the O-shaped sealing valve seat can be selected to achieve two-way sealing. Knife gate valve has small installation space, low working pressure, not easy to accumulate debris, and low price.

When the knife gate valve is closed, the sealing surface can only be sealed by the medium pressure, that is to say, the sealing surface of the gate valve is pressed to 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 valve must be forced to the valve seat by external force to ensure the sealing of the sealing surface.

The gate valve is suitable for slurry and medium pipe containing fiber, its knife shaped gate can cut off the fiber material in the medium, and it is widely used in coal slurry, mineral slurry and paper slag slurry pipeline;

Knife gate valve is a derivative of gate valve, with its unique advantages and disadvantages,


advantage:

1 hard sealing knife gate valve is the first choice valve product for slurry, slurry and pulp pipeline;

2. Simple structure, small volume, light weight and convenient installation;

Disadvantages of knife gate valve: it can only be used in low pressure pipeline

Gate valve is a large class, divided into many models, many structures, suitable for many working conditions;

Knife gate valve is mainly used in slurry pipeline, also can be said to be a special valve for slurry pipeline;


Application of knife gate valve:

1. Knife gate valve is suitable for gold powder, tailings, pulp, wood pulp, fiber, dust, chemical treatment of sewage, sedimentation tank, ore, slag, slime, asphalt, silo outlet, fruit, grain, cement slurry, slaughterhouse wastewater, etc.

2. Knife gate valve can be equipped with handwheel, manual zipper, spur gear drive, bevel gear drive, pneumatic and electric.

3. The inside of knife gate valve can be made into V-shaped, triangular and pentagonal channels. V-shaped RAM can be used as adjustment control.

4. The knife gate valve is connected in the form of clamp and flange lug. The seal is metal to metal hard seal, metal to polyurethane, and PTFE soft seal with reinforcement

how does a knife gate valve work