Knife Gate Valve for Mining And Coal Washing - Suitable for Ash Slag And Solid Particles With Heavy-Duty Cast Steel Body

The knife gate valve is a type of gate valve introduced to China in the 1980s. Its opening and closing element is a gate disc, which moves perpendicular to the flow direction, shutting off the medium with a blade-shaped disc that can cut through fibrous materials. It is a linear shut-off valve with a beveled cutting edge on the disc head, providing a certain shearing effect on the medium. It is suitable for use in media containing fibers and solid particles, as well as in sewage treatment systems. It can be equipped with manual, pneumatic, or electric actuators and is widely used in process automation systems in mines, power plants, coal preparation, slag removal, cement, papermaking, mining, chemical industry, and sewage treatment. A knife gate valve, also known as a knife-type gate valve, knife-gate gate valve, slurry valve, or mud valve, operates with a disc. The disc moves perpendicular to the flow direction, cutting the medium with a blade-shaped blade that can cut through fibrous materials. The disc has two sealing surfaces. The most commonly used disc valve has two sealing surfaces that form a wedge shape. The wedge angle varies with valve parameters, typically 5°. The disc of a wedge-type knife gate valve can be a single piece, known as a rigid disc, or it can be slightly deformed to improve processability and compensate for deviations in the sealing surface angle during machining. This type of disc is known as an elastic disc. The valve body does not actually have a cavity. The disc rises and falls within a side guide groove and is pressed against the valve seat by a lug on the bottom. For higher media sealing performance, an O-ring seat can be used to achieve bidirectional sealing. Knife gate valves require a compact installation space, low operating pressure, and are less susceptible to debris accumulation. When a knife-type gate valve is closed, the sealing surface relies solely on the medium pressure to press the gate disc's sealing surface against the valve seat on the other side, ensuring a tight seal. This is known as self-sealing. Most gate valves use forced sealing, meaning that when the valve is closed, external force is used to press the gate disc against the valve seat to ensure a tight seal. This type of valve should generally be installed vertically in the pipeline.

Knife-type gate valves are available in a variety of actuation methods: manual, electric, and pneumatic.

Knife-type gate valves are available in two configurations: rising stem and concealed stem.

Knife-type gate valve materials: cast iron, cast steel, carbon steel, stainless steel, and fluorine-lined.

Knife-type gate valve seals are available in a variety of materials: hard seals, soft seals, single-sided seals, and double-sided seals. Knife gate valves are used in the following areas:

1. Mining, coal washing, and steel industries—for coal washing pipelines, filter slurry pipelines, and ash discharge pipelines;

2. Purification plants—for wastewater, slurry, dirt, and clarified water containing suspended solids;

3. Papermaking—for pulp of any consistency and material-water mixtures;

4. Power plant ash removal—for ash slurries;

Performance:

1. The valve can be controlled locally and remotely, and remote position display and centralized control can be implemented according to user requirements.

2. Lightweight: The body is made of carbon steel, weighing approximately 20%-30% less than traditional gate valves, making installation and maintenance easy.

3. Using this valve improves the sealing performance of pipeline systems, minimizing leakage, and actively contributes to improving production efficiency and protecting the environment.

4. The sealing surface is made of highly wear-resistant and corrosion-resistant ceramic material, and the inlay technology provides high corrosion and wear resistance, resulting in a long valve life and a cost-effectiveness that is 10 times higher than that of ordinary valves. 

Features:

1. The lifting gate seal scrapes away sticky debris and automatically cleans debris.

2. The stainless steel gate prevents leaks caused by corrosion.

3. The hardened, all-metal seal ensures wear resistance and meets required sealing requirements.

4. The triangular bracket saves material and ensures the required mechanical properties.

5. The valve body seal surface is free of grooves, preventing buildup and ensuring flexible opening.

6. The short construction saves material and installation space while effectively supporting pipeline strength.

7. The scientifically designed upper seal stuffing box ensures a safe, effective, and durable upper seal.

8. The guide block on the valve body ensures correct gate movement, and four squeeze blocks ensure effective sealing.

9. The valve body reinforcement rib design enhances valve strength.

10. The stainless steel stem is durable, and the stud bolts ensure quick opening and closing.

11. Optional drive mechanism available. 12. For diameters DN150 and above, a fully enclosed structure is used for more effective opening and leakage prevention.

13. The fluororubber sealing surface provides a strong seal and increases the operating temperature.

14. The rubber sealing surface is vulcanized directly into the valve body and will not fall off.

The opening and closing element of a knife-type gate valve is the gate disc, which moves perpendicular to the flow direction. Knife-type gate valves can only be fully opened and fully closed and cannot be adjusted or throttled. When closed, the sealing surface relies solely on the medium pressure to maintain a tight seal. Most knife-type gate valves use a forced seal, meaning that when the valve is closed, an external force is used to press the gate disc against the valve seat to ensure a tight seal.