5、 Conclusion All welded pneumatic ball valve is a typical narrow gap submerged arc welding product, which involves many aspects of knowledge such as material science, welding technology, automatic development of welding equipment, 3D thermal elastoplastic finite element calculation, and design of pipeline pneumatic ball valve. With the construction of a large number of national key pipeline projects such as the West East Gas Pipeline Project, the West Crude Oil and Product Oil Pipeline Project, and the Sichuan East Gas Pipeline Project, the progress in localization technology, equipment, manufacturing and process of all welded pneumatic ball valves has been greatly promoted, and the wells are gradually becoming mature and perfect, starting to develop in the direction of large diameter and high pressure. Through the analysis of the influencing factors of weld formation and weld metal mechanical properties, as well as the welding test results, the valve body structure, weld groove form and valve seat structure are reasonably designed, the chemical composition of the valve body raw materials is strictly controlled, the reasonable welding wire flux and process parameters are selected, and the narrow gap groove multi pass and multi-layer welding is adopted, The interlayer temperature in the welding process shall be controlled timely to fully meet the welding production requirements of all welded pneumatic ball valves.

1. Remove the protective covers on both sides of the flange end, and flush and clean the valve when the valve is fully opened.
2. Before installation, the whole machine shall be tested according to the specified signal (electricity or gas) (to prevent vibration caused by transportation from affecting the service performance), and it can be installed online only after it is qualified (wiring shall follow the circuit diagram of electric actuator).
3. Before preparing to connect with the pipe, the residual impurities in the pipe must be flushed and removed (these substances may damage the valve seat and ball).
4. During installation, please do not use the actuator part of the valve as the lifting point to avoid damage to the actuator and accessories.
5. This type of valve shall be installed in the horizontal or vertical direction of the pipeline.
6. The pipeline near the installation point shall not sag or bear external force, and the pipeline support or support can be used to eliminate the deviation of the pipeline.
7. After connecting with the pipeline, please cross lock the flange connecting bolts with the specified torque.