Knife gate valve

Yongjia Shitong Valve Manufacturing Co., Ltd.


Knife gate valve has entered China since the 1980s. In less than two decades, its scope of use has expanded from the general field to a wider range of industries, from coal preparation , drainage, and slag discharge of mine power plants. Urban sewage treatment has evolved from general industrial pipelines to specialized pipeline systems such as food, sanitation, and medicine.


Knife gate valve, also known as knife gate valve, knife gate valve, slurry valve, mud valve, its opening and closing parts is the gate, the gate movement direction is perpendicular to the direction of the fluid, can be cut by cutting the fiber material blade gate Medium, the gate has two sealing surfaces, the two sealing surfaces of the most commonly used mode gate valve form a wedge, wedge angle varies with the valve parameters, usually 50, the gate of the wedge knife gate valve can be made into a whole It can be called a rigid gate; it can also be made into a gate that can produce a slight amount of deformation, in order to improve its craftsmanship, and make up for the deviation of the sealing surface angle during processing. Such a gate is called a flexible gate. The valve body does not actually exist in the chamber, and the gate plate is raised and lowered in the side guide groove, and the lug on the bottom is pressed against the valve seat. If a high medium tightness is required, O-seal valve seat can be used to achieve Bidirectional seal. Knife gate valve has a small installation space, low working pressure, is not easy to accumulate debris, and the price is low.

When the knife-type gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, relying on the medium pressure to press the sealing surface of the gate plate to the valve seat on the other side to ensure the sealing of the sealing surface. This is the self-sealing. Most of the gate valves are The use of forced sealing, that is, when the valve is closed, must rely on external force to force the gate to the valve seat to ensure the sealing surface of the seal. This type of valve should generally be installed vertically in the pipeline.

Knife gate valve drive mode: manual, sprocket, electric, pneumatic, hydraulic, bevel gear, electronically controlled hydraulic and gas-liquid dynamic driving methods. Knife gate valve shape: light rod, dark rod two. Knife gate valve material: cast iron, cast steel, carbon steel, stainless steel, fluorine-lined. Knife gate valve seal: hard seal, soft seal, single-sided seal, double-sided seal and other materials sealed.

The ultra-thin knife gate valve completely solves the large flow resistance of ordinary gate valves, flat gate valves, ball valves, globe valves, regulating valves, and butterfly valves due to its small size, small flow resistance, light weight, easy installation, and easy disassembly. , heavy weight, difficult installation, large area and other difficult problems. After the knife gate valve appeared, a large number of universal cut-off valves and regulating valves had been replaced. To this day, the largest use of knife gate valves in the world is the United States and Japan.

The range of knife gate valves is:

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

2. Purification device - used for wastewater, mud, dirt and clarified water with suspended solids;

3 paper industry - for any concentration of pulp, feed water mixture;

4. Ash removal from power station - used for ash slurry.


(1) Body, (2) Bracket, (3) Handwheel: Ductile Iron

(4) spool: stainless steel

(5) rubber gasket

(6) PTFE plate

(7) Packing: PTFE seal

(8) Pressure Cover: Stainless Steel

(9) Lead screw, (10) Stem nut: Stainless steel

(11) Matching cap: 35#


1. The valve control can be controlled locally and remotely. It can also realize remote location display and remote centralized control according to the user's requirements.

2. Light weight: The body is made of carbon steel, which weighs about 20%-30% lighter than the traditional gate valve. It is easy to install and maintain.

3. The use of this valve can improve the closing and sealing performance of the pipeline system, eliminate leaks to the maximum extent, and play a positive role in promoting production efficiency and environmental protection.

4. The sealing surface is made of highly wear-resistant, corrosion-resistant ceramic materials with inlaid technology, high corrosion resistance, and good wear resistance, resulting in long valve life and cost-effective improvements of up to 10 times compared to conventional valves.


Knife-type gate valve made of dark rods and light rods according to different caliber.
Knife gate valve can be made into V-shaped, triangular, pentagonal channels. The V-shaped gate can be used as a regulating control.

Connection Type

One, clip type

Second, flange flange type

transfer method

First, manual

1.1 Handwheel

1.2 manual zipper

Second, worm gear drive

2.1 spur gear transmission

2.2 Bevel gear transmission

Third, pneumatic

Fourth, electric

Fifth, hydraulic and other

control method

First, manual control

Second, pneumatic control

Third, electromagnetic control

Fourth, simulation of remote computer control.


First, the lifting shutter sealing surface can scrape off the adhesive on the sealing surface and automatically clean up debris.

Second, stainless steel gate plate can prevent leakage caused by seal leakage.

Third, the hard full gold sealing surface can guarantee the sealing wear resistance and requirements.

4. There is no groove on the sealing surface of the valve body, no accumulation is generated, and it can ensure flexible opening.

Fifth, the short structure length can save raw materials and installation space and also effectively support pipeline strength.

Sixth, the scientific design of the sealed stuffing box makes the seal safe, effective and durable.

Seventh, the triangular bracket saves raw materials and ensures the required mechanical properties.

Eight, the guide block on the valve body makes the gate move correctly, and the four press blocks ensure that the gate plate seals effectively.

Nine, valve body reinforcement design to improve the strength of the valve body.

Tenth, stainless steel valve stem is durable, stud bolt makes opening and closing more quickly.

Eleven, can choose any drive mechanism.

Twelve and more than 150 calibers adopt fully enclosed structure, which can effectively open and prevent leakage.

Thirteen, fluorine rubber sealing surface can achieve sealing effect, improve the use of temperature.

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

Installation and use instructions

1. Before the knife gate valve is installed, it is necessary to check the inside of the valve chamber and the sealing surface, and no dirt or grit is allowed to adhere;

2. The bolts at each connection must be tightened evenly;

3. Inspect the packing area for compaction, which not only guarantees the sealability of the packing, but also guarantees that the gate plate can be opened flexibly;

4. Before the user installs the valve, the model of the valve must be calibrated, the connection size and the direction of the medium should be observed to ensure consistency with the valve requirements.

5. The user must reserve the necessary space for valve actuation when installing the valve;

6. The wiring of the drive device must be in accordance with the wiring diagram;

7. The knife gate valve must be maintained regularly and must not be crushed and squeezed freely to avoid affecting the seal.


1. Handwheels, handles and transmission mechanisms are not allowed to be lifted, and collisions are strictly prohibited.

2. The double gate valve shall be installed vertically (ie the valve stem is in vertical position and the handwheel is at the top).

3. The gate valve with bypass valve should open the bypass valve before opening (to balance the pressure difference between the inlet and outlet and reduce the opening force).

4. The gate valve with transmission mechanism shall be installed in accordance with the product instructions.

5, if the valve is used regularly, lubricate at least once a month.

Executive standard


The pressure-temperature rating of the shell material is in accordance with the provisions of GB 9131.

Valve body structure length and limit deviation according to GB/T 15188.2

Flange connection size and sealing surface type have special requirements specified in the order.

The trapezoidal thread is adopted for the stem and the stem nut, and the basic dimensions and tolerances are in accordance with GB 5796.1-5796.4.

The connection dimension between the bracket and the drive device shall be in accordance with the provisions of GB 12222.

Valve body using WCB material, according to the provisions of GB12229.

The gates are made of austenitic stainless steel (SS304) according to the provisions of GB 12220 and GB 4237.

The valve stem uses 1Cr13, 2Cr13 material, according to the provisions of GB12220.

Brackets and packing glands are made of carbon steel (WCB) material according to the provisions of GB12229.

Stem nut using copper alloy (ZCuZn38Mn2Pb2, ZCuSn5Pb5Zn5), according to the provisions of GB 12225.

The upper seal (filler) uses graphite asbestos rope.

Shell test and seal test according to GB/T 13927's.

Leakage of the seal test is calculated as 1 × mm/s for the required effective sealing performance.

Gas valve cleaning requirements in accordance with the provisions of JB/T 7748.

Paint color according to JB 106.

The gas gate valve packaging, storage, transportation and quality assurance according to JB/T 7928 regulations.

Shell pressure: 1.5MPa, seal pressure: 1.1 pressure, applicable temperature: 425 °C, applicable medium: sewage, gas, pulp and so on.



The opening and closing part of the knife-type gate valve is a gate plate. The movement direction of the gate plate is perpendicular to the direction of the fluid. The knife-type gate valve can only be fully opened and fully closed, and can not be adjusted or throttled. The gate has two sealing surfaces, usually 50, and the gate of the wedge-type gate valve can be made into a whole, which is called a rigid gate; it can also be made of a gate that can generate slight deformation, so as to improve its processability. To make up for the deviation of the sealing surface angle during the machining process, this kind of gate is called elastic gate. When the knife gate valve is closed, the sealing surface can only be sealed by means of medium pressure. Most knife-type gate valves use forced sealing, that is, when the valve is closed, it is necessary to force the gate plate to press against the valve seat in order to ensure the sealing performance of the sealing surface.

Purchase instructions

1. When the user purchases, it must indicate the valve nominal pass, pressure and valve connection standards;

2. If there are special requirements for the required valve, all parameters such as special dimensions and special materials must be specified.

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