Gate valves can be used in natural gas transmission systems, but they must meet specific working conditions and safety standards. The following is a specific analysis:
1. Applicability analysis
Sealing reliability
The gas gate valve adopts an elastic sealing structure (such as a wedge-type elastic gate), and through the optimization of the sealing surface material (hard alloy surfacing or rubber wrapping), it can withstand the high-pressure impact of the natural gas medium and achieve zero leakage. Some buried models are designed with pressure discharge holes to balance the force on the valve body and avoid sealing failure caused by temperature difference.
Structural adaptability
Full-diameter design: Reduce flow resistance, facilitate the passage of pipeline sweepers, and adapt to the needs of long-distance pipelines.
Low structural height: Reduce the depth of buried installation and save construction costs.
Opening and closing indicator: Equipped with a fully enclosed indicating device, it is easy to quickly confirm the valve status and avoid misoperation.
Material corrosion resistance
Natural gas contains corrosive components such as hydrogen sulfide. The valve body and sealing surface need to use corrosion-resistant materials such as anti-sulfur steel and Stellite cobalt-based alloy to extend the service life.
2. Application scenarios
Trunk pipeline network
Used for opening and closing control of long-distance natural gas pipelines, such as buried flat gate valves that can withstand geological settlement and external loads to ensure system stability.
Pressure regulating station and distribution station
As a cut-off valve, it cooperates with ball valves, butterfly valves, etc. to achieve pressure segmentation control to ensure gas supply safety.
Industrial user end
In chemical plants, power plants and other occasions that require frequent opening and closing, the flow resistance is close to zero when the gate valve is fully opened, which is suitable for large flow transmission.
3. Selection and use points
| Item | Require |
|---|---|
| Seal Type | Prefer elastic seal or hard seal + auxiliary lubrication structure to adapt to pressure fluctuations |
| Drive mode | It is recommended that buried valves be equipped with fully enclosed gearboxes or gas-liquid linkage devices to support remote control |
| Maintenance requirements | Maintenance-free design (such as fully welded valve body) reduces maintenance frequency |
| Safety regulations | Must comply with CJ3055 and other standards and pass 1.1 times nominal pressure sealing test |
4. Limitations and alternatives
High impurity conditions: If the natural gas contains particulate matter, the gate valve sealing surface is easy to wear, and the ball valve is preferred.
Regulation requirements: When flow regulation is required, the gate valve is not applicable (only fully open/fully closed), and should be used with a stop valve or a regulating valve.
