In long-distance pipelines, the line shutoff valve - pipeline ball valve is required to control the medium in the pipeline, have a switch function, change the flow direction of the medium and prevent backflow, send or pass the pipeline cleaning ball to prevent accidents, automatically and urgently cut off, close or open the pipeline, etc.
1. Reliable sealing performance
Long-distance pipelines can only be inspected or patrolled regularly, and sometimes need to pass through remote mountains, deserts, grasslands and earthquake areas. A small leakage will cause a large amount of medium leakage and waste energy. Especially in the West-East Gas Transmission Project, the sealing of the natural gas pipeline is more important. In addition, it is also required to have the sealing performance of emergency grease injection.
2. Long service life requirements
Once the pipeline is put into operation, it is not allowed to stop operating within a few years or even decades. The longer the operation time, the better. Natural gas faces large users, is the raw material or energy of large factories and enterprises, and is not allowed to be shut off for a moment. Therefore, the main key parts such as valve seats are required to have a long life.
3. High strength and safety of pipeline valves against external forces In the West-East Gas Transmission Project, the pressure of pipeline ball valves is as high as 10.0MPa. The diameter reaches 1000mm. In addition, the station distance of the pipeline is relatively long, with a length of about 20 kilometers. During use, the valves are often subjected to comprehensive stresses such as tension, bending and compression in the pipeline due to complex external forces such as thermal expansion and contraction of temperature, equipment vibration, earthquake disasters, and foundation changes. To ensure the normal use of the valve, it must have sufficient strength.
4. Pipeline ball valves should be corrosion-resistant Because natural gas contains hydrogen sulfide, it can also react with iron to form iron sulfide, corrode valves, and corrode machinery, so pipeline ball valves should be made of corrosion-resistant materials.
5. High degree of automation The control of pipeline ball valves is all in the central control room, which is far away. It should be able to implement long-distance control or remote control, and can be shut down in an emergency state. The shutdown time is required to be about 15 seconds. When the pipeline is operating normally, it may not move for several years. Once it moves, it must be accurate and reliable.
6. Pipeline valves are required to be light in weight, compact in structure, and full in diameter. In order to ensure that the valves can be installed on complex sites, buried underground, and easy to maintain, the valves are required to be light in weight, compact in structure, and full in diameter to facilitate cleaning during normal operation of the pipeline.