Flat gate valve structure diagram Flat gate valve is a sliding valve with parallel gate as the closing element. The closing component can be a single gate or a double gate with a support mechanism in between.

The clamping force of the gate to the valve seat is controlled by the medium pressure acting on the floating gate or floating valve seat. If it is a double gate flat gate valve, the expansion mechanism between the two gate plates can supplement this clamping force.

Classification of gate valves

Flat gate valves can be divided into manual flat gate valves, pneumatic flat gate valves, and electric flat gate valves according to their driving methods. According to their purposes and usage scenarios, they can be divided into flat gate valves with diversion holes, flat gate valves without diversion holes, oil field flat gate valves, pipeline flat gate valves, and gas flat gate valves.

Usage characteristics

Adopting a new floating sealing structure, it is suitable for oil, natural gas and other pipelines with a pressure not exceeding 15.0MPa and a temperature of -29~121 ℃. As a control medium for opening, closing and regulating devices, this product has a novel structural design, appropriate material selection, strict testing, and easy operation. It has strong anti-corrosion, wear-resistant and erosion resistance performance and is an ideal new equipment in the petroleum industry.

working principle

1. Adopting a floating valve seat, bidirectional opening and closing, reliable sealing, and flexible opening and closing.

2. The gate has guide strips for precise guidance, and the sealing surface is sprayed with hard alloy for erosion resistance.

3. The valve body has high load-bearing capacity, and the channel is straight through. When fully opened, it is connected to the gate guide hole and is similar to a straight pipe, with very low flow resistance. The valve stem adopts composite packing and multiple seals, ensuring reliable sealing and low friction.

4. When closing the valve, turn the handwheel clockwise to move the gate down to the bottom. Due to the pressure of the medium, the inlet sealing seat is pushed towards the gate direction, forming a larger sealing pressure ratio and thus forming a channel seal. At the same time, press the gate onto the sealing seat at the outlet end to form a double seal.

Due to the use of double sealing, vulnerable parts can be replaced without affecting the operation of the pipeline. This is an important feature that sets our factory's products ahead of similar products both domestically and internationally.

When opening the gate, rotate the handwheel counterclockwise to move the gate up and connect the guide hole with the channel hole. As the gate rises, the through hole gradually increases. When it reaches the limit position, the diversion hole coincides with the channel hole and is fully opened.

internal structure

1. The valve seat adopts an O-ring seal and a floating valve seat structure with pre tightening force, which enables bidirectional sealing of the inlet and outlet of the flat gate valve; And the opening and closing torque of this structure is only half of that of ordinary valves, which can achieve easy opening and closing of valves

When fully open, the channel is smooth and straight, with a very small flow resistance coefficient and no pressure loss. It can be cleaned by passing a rough ball through the pipeline

3. Adopting a packing structure with self sealing ability, it does not require frequent adjustment, and the opening and closing are extremely lightweight with reliable sealing performance. The packing box is equipped with an auxiliary sealing grease injection structure, which ensures absolutely reliable sealing performance and truly achieves zero leakage; Solved the problem of easy leakage at the packing of universal valves

4. When the flat gate valve is closed, it can automatically release the high pressure inside the chamber, ensuring safe use

5. Fully enclosed structure, good protective performance, can adapt to all-weather requirements

The sealing structure of the valve seat should be elastic with pre tightening force, and the upstream and downstream sealing seats should be sealed simultaneously. The valve seat and seal are always sealed face-to-face.

7. The valve seat has a self-cleaning function and is not directly flushed by the airflow during the valve opening or closing process. The valve seat should be made of lubricated and wear-resistant materials.

8. The malfunction of the valve actuator will not affect other parts of the valve, and maintenance and replacement work can be carried out without disassembling the valve.

9. Yoke sleeve - The aluminum bronze yoke sleeve is equipped with needle shaped thrust bearings to reduce operating torque.

10. Valve stem - thread length up to the bracket; Pin and spot welding; Has stability.

11. Pressure seal - simple structure, equipped with segmented retaining rings and silver plated low-carbon steel gaskets, which helps to disassemble and achieve good valve cap sealing.

12. Valve Seat Ring - Welded valve seat ring perpendicular to the flow channel, easy to maintain.

13. Execution mechanism - These valves can be equipped with electric, hydraulic, or pneumatic actuators. Manual handwheel with standard configuration below DN300, and helical gear operating mechanism with configuration above DN350.

14. Yoke - The fully assembled yoke has passed seismic testing and is easy to maintain and install the actuator.

15. Cover - Two piece, self-adjusting cover to avoid popping out.

16. Overall rear seat - hard surface, long service life.

17. Valve disc - Spring loaded valve disc can adjust itself, reducing the torque demand of the actuator.

18. Integral Stop - The integral casting bracket stop device positions the assembled bracket valve disc, making the valve seat more stable and reliable.

19. The valve body has two structures: casting and welding.

20. The valve seat adopts an O-ring seal and a floating valve seat structure that applies pre tightening force, ensuring bidirectional sealing of the valve inlet and outlet; And the opening and closing torque of this structure is only half of that of ordinary valves, which can achieve easy opening and closing of valves.

21. Metal to metal sealed valves are equipped with grease injection structures on the outside of the valve body. The grease enters the valve sealing surface through the grease injector and valve seat, achieving zero leakage of the valve.

22. The valve seat adopts PTFE embedded on the sealing surface, which has dual sealing of PTFE to metal and metal to metal. The PTFE sealing surface also has the function of removing dirt from the gate plate.

23. The gate and valve seat are treated with special technology, sprayed with hard alloy, wear-resistant PTFE, and achieve dual sealing. And it can be filled with grease to assist in dual protection sealing, making the sealing more reliable and the service life longer.

24. The gate with a diversion hole valve always matches the sealing surface, whether fully open or fully closed, and the sealing surface is protected from direct flushing by the medium, thereby extending its service life.

When the valve is fully opened, the channel is smooth and straight, the flow resistance coefficient is extremely small, there is no pressure loss, and the pipeline can be cleaned by passing a rough ball.

26. This valve adopts a packing structure with self sealing ability, which does not require frequent adjustment. It is extremely easy to open and close, and the sealing performance is reliable. The packing box is equipped with an auxiliary sealing grease injection structure, and the sealing performance is absolutely reliable, truly achieving zero leakage; Solved the problem of easy leakage at the packing of universal valves.

When the valve is closed, it can automatically release the high pressure inside the chamber, ensuring safe use.

28. Fully enclosed structure, good protective performance, can adapt to all-weather requirements.

29. Valves are equipped with indicator rods or observation windows to indicate the opening and closing status of the valve.

performance specifications

Nominal pressure 1.0 1.6 2.5 4.0 6.4 10.0

Nominal diameter DN40-DN700

Working pressure (MPa) ≤ 1.0 ≤ 1.6 ≤ 2.5 ≤ 4.0 ≤ 6.4 ≤ 10.0

Strength test (MPa) 2.0 2.4 3.75 6.0 9.6 15.0

Sealing test (MPa) 1.1 1.76 2.75 4.4 7.1 11.0

Working media include water, oil, natural gas, etc

Working temperature -29~121 ℃

Suitable occasions

1. (Class 150-900/PN1.0-16.0MPa, working temperature -29~121 ℃) Petroleum and natural gas transmission pipelines. Flat gate valves with diversion holes are also convenient for cleaning pipelines.

2. Transportation pipelines and storage equipment for finished oil products.

3. Oil and gas extraction wellhead equipment, also known as Christmas tree valves.

4. Pipelines containing suspended particles.

5. Urban gas transmission pipelines.

6. Water supply project.

Selection principle

1. For the transportation pipelines of oil and natural gas, single or double gate flat gate valves should be selected. If pipeline cleaning is required, choose a single or double gate open stem flat gate valve with a guide hole.

2. For the transportation pipelines and storage equipment of finished oil products, single or double gate flat gate valves without diversion holes shall be selected.

3. For oil and gas extraction wellhead equipment, single or double gate flat gate valves with concealed floating seats and guide holes are selected, mostly in accordance with API16A standards, with pressure ratings of API2000, API3000, API5000, API10000, API15000, and API20000.

4. For pipelines with suspended particulate media, knife type flat gate valves should be selected.

5. For urban gas transmission pipelines, single or double gate soft sealed rising stem flat gate valves should be selected.

6. For urban water engineering, single or double gate open stem flat gate valves without diversion holes shall be selected.

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