knife gate valve

knife gate valve


Knife gate valve is also known as knife gate valve, knife gate valve, slurry valve, mud valve, its opening and closing parts are gate, the direction of the movement of the gate is perpendicular to the direction of the fluid, by cutting fiber material blade gate to cut off the medium, The two sealing faces of the most common type gate valve form a wedge.

knife gate valve

Knife gate valve is also known as knife gate valve, knife gate valve, slurry valve, mud valve, its opening and closing parts are gate, the direction of the movement of the gate is perpendicular to the direction of the fluid, by cutting fiber material blade gate to cut off the medium, The two sealing faces of the most common type gate valve form a wedge. The wedge Angle varies with valve parameters, usually 5°. The wedge knife gate valve gate can be made into a whole, called a rigid gate; It can also be made into a gate that can produce slight deformation to improve its technology and compensate for the deviation of sealing face Angle in the process of processing. This gate is called an elastic gate. In fact, there is no chamber in the valve body, the gate in the side guide groove lifting, and by the bottom of the lug pressed on the seat, if you need to achieve a higher medium sealing, you can choose O seal seat to achieve two-way sealing. Knife gate valve has a small installation space, low working pressure, not easy to accumulate debris, low price.

Type knife gate valve is closed, sealing surface can only rely on medium pressure to seal, that depend on medium pressure, the disc will be to the other side of the valve seat sealing surface pressure to ensure that the sealing surface sealing, it is the seal, most is adopt compulsory seal gate valve, the valve is closed, to rely on outside force forced the ram pressure to the seat, to ensure the sealing surface sealing. This kind of valve should be installed vertically in the pipeline.

Knife gate valve drive mode: manual, sprocket, electric, pneumatic, hydraulic, bevel gear, electric control hydraulic and gas hydraulic drive mode. Knife gate valve appearance: open rod, dark rod two. Knife gate valve material: cast iron, cast steel, carbon steel, stainless steel, fluorine lining, etc.

Knife gate valve sealing: hard sealing, soft sealing, single-sided sealing, double-sided sealing and other materials.

Ultra-thin knife gate valve with its small volume, small flow resistance, light weight, easy to install, easy to disassemble and other advantages completely solve the flow resistance of ordinary gate valve, flat gate valve, ball valve, globe valve, regulating valve, butterfly valve and other valves, heavy weight, difficult to install, cover an area of large problems. With the advent of knife gate valves, a large number of general purpose shut-off valves and regulating valves have been replaced by them. The world's largest knife gate valve consumption is the United States and Japan.

The scope of use of knife gate valve is:

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

2. Purification device -- used for waste water, mud, dirt and clarification water with suspended matter;

3. Paper industry -- used for any concentration of pulp, material and water mixture;

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


(1) the body

(2) support

Knife gate valve structure drawing

Knife gate valve structure drawing

(3) Hand wheel: ductile iron

(4) Spool: stainless steel

(5) Rubber gasket

(6) ptfe orifice plate

(7) Packing: ptfe sealing ring

(8) Pressure cover: stainless steel

Screw (9),

(10) Stem nut: stainless steel

(11) Cap: 35#


1. Valve control can do local and remote control, but also in accordance with the requirements of users to achieve remote location display and remote centralized control.

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

3. The use of the valve can improve the closed sealing performance of the conveying pipeline system, eliminate leakage to the maximum, improve production efficiency, protect the environment will play a positive role in promoting.

4. The sealing surface is made of high wear-resistant and corrosion-resistant ceramic materials, with Mosaic technology, high corrosion resistance and good wear resistance, so that the valve has a long life and the cost performance is 10 times higher than that of ordinary valves.

Knife gate valve according to the caliber of different made of dark rod and open rod two forms.

Knife gate valve can be made into V - shaped, triangular, pentagonal channels. V - gate can be used as regulating control.
Transmission mode:

A, manual

1.1 the handwheel

1.2 Manual Zipper

Worm gear and worm drive

2.1 Spur gear transmission

2.2 Bevel gear transmission

Three, pneumatic

Four, electric

Five, hydraulic, etc

Control mode:

First, manual control

Two, pneumatic control

Three, electromagnetic control

Four, analog remote computer control.


1. The lifting gate sealing surface can scrape off the sticky material on the sealing surface and automatically clean up the sundries.

Two, stainless steel gate can prevent corrosion caused by sealing leakage.

Three, hard full gold sealing surface can ensure the wear-resisting performance and requirements of the seal.

Four, there is no groove on the sealing surface of the valve body, which can ensure flexible opening.

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

Scientific upper seal stuffing box design, make the upper seal safe and effective, durable.

Seven, triangular bracket saves raw materials, to ensure the mechanical properties required.

Eight, the valve body of the guide block to make the correct movement of the gate, four extrusion block to ensure the effective sealing of the gate.

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

Ten, stainless steel valve stem durable, double head bolt to open and close more quickly.

Eleven, can choose any driving mechanism.

12, more than 150 caliber, using fully closed structure, more effective opening and prevent leakage.

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

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

Installation instructions:

1. Before installation of knife gate valve, check the valve cavity and sealing surface and other parts, no dirt or sand particles are allowed to adhere to;

2. Bolts at all connection parts should be tightened evenly;

3. Check the packing parts to ensure the sealing of the packing and flexible opening of the gate;

4. Before installing the valve, the user must check the valve model, connection size and pay attention to the medium flow to ensure consistency with the valve requirements;

5. When installing the valve, the user must reserve the necessary space for the valve drive;

6. Wiring of the driving device shall be carried out according to the circuit diagram;

7. Knife gate valve must be maintained regularly, do not collision and extrusion at will, so as not to affect the seal.


1. Handwheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited.

2, double disc gate valve should be installed vertically (that is, stem in vertical position, handwheel at the top).

3, the gate valve with bypass valve should be opened before opening the bypass valve (to balance the inlet and outlet pressure difference and reduce the opening force).

4. The gate valve with transmission mechanism shall be installed according to the instructions of the product.

5. Lubricate at least once a month if the valve is often on/off .

Execution standard:

The pressure - temperature grade of shell material is in accordance with GB9131.

The structural length and limit deviation of valve body shall be specified in GB/T 15188.2

Special requirements for flange connection size and sealing surface type should be indicated in the order.

The valve stem and valve stem nut are trapezoidal threads, and their basic dimensions and tolerances are specified in GB 5796.1 ~ 5796.4.

The connection size of the bracket and the driving device shall be in accordance with GB 12222.

The valve body shall be made of WCB material according to GB12229.

The gate is made of austenitic stainless steel (SS304) according to GB 12220 and GB4237.

The valve stem is made of 1Cr13 and 2Cr13 materials according to GB12220.

The support and packing gland are made of carbon steel (WCB) according to GB12229.

Stem nut is made of copper alloy (ZCuZn38Mn2Pb2, ZCuSn5Pb5Zn5), according to GB 12225.

The upper seal (packing) is made of graphite asbestos rope.

Shell test and seal test according to GB/T 13927.

For the requirement of effective sealing performance, the leakage of sealing test shall be calculated by 1×mm/s.

Gas gate valve cleaning requirements according to JB/T 7748.

Paint color according to JB 106.

The packing, storage, transportation and quality assurance of gas gate valves shall be in accordance with JB/T 7928.

Shell pressure: 1.5mpa, sealing pressure: 1.1 pressure, applicable temperature: 425℃, applicable medium: sewage, gas, pulp and so on.