7. Applicable principle of pneumatic ball valve: for the main pipeline of oil and natural gas transmission, the pipeline that needs to be cleaned, and the pipeline that needs to be buried underground, the pneumatic ball valve with full diameter and full welding structure shall be selected; For those buried on the ground, the pneumatic ball valve connected by welding or flange shall be selected; Branch pipes shall be flanged, welded and full bore or reduced pneumatic ball valves. Flange connected pneumatic ball valve shall be used for product oil transmission pipeline and storage equipment. The floating pneumatic ball valve with flange connection and internal thread connection is selected for the pipeline of city gas and natural gas. In the oxygen pipeline system of the metallurgical system, it is advisable to select the flange connected fixed ball pneumatic ball valve that has undergone strict degreasing treatment. Low temperature pneumatic ball valve with valve cover should be selected for pipeline system and device of low temperature medium. The lifting rod pneumatic ball valve can be selected for the pipeline system of the catalytic cracking unit of the oil refining unit. All stainless steel pneumatic ball valves made of austenitic stainless steel and with polytetrafluoroethylene as the seat sealing ring should be selected for devices and pipeline systems with corrosive media such as acid and alkali in the chemical system. Metal to metal sealed pneumatic ball valves can be selected for pipeline systems or devices of high-temperature media in metallurgical systems, power systems, petrochemical plants and urban heating systems. When flow regulation is required, worm gear driven, pneumatic or electric regulating pneumatic ball valve with V-shaped opening can be selected.

2. Valve body inspection Every six months, check whether the valve body appearance is good, whether the installation flange has leakage, if it is convenient to check whether the valve body seal is good, whether there is wear, whether the valve plate operates flexibly, and whether the valve has foreign matters stuck.