(2) The seal between valve seat and valve body adopts hard sealing structure, which is suitable for high temperature and high pressure working conditions. The size c of the sealing contact surface between the valve seat and the valve body is small, and the accuracy requirements of each sealing surface are high. During the assembly, the retainer is installed with an electric impact wrench, which not only meshes the retainer with the valve body to prevent looseness, but also friction rotation of the valve seat, which conforms to the mechanical vibration meshing principle, so that the valve seat and the valve body can be reliably sealed.
(3) The valve seat and valve body, as well as the valve seat and hemisphere are hard sealed at two points, so the valve can be used in high temperature and high pressure conditions.
2.3. The valves of other parts and components are of modular design, simple structure, good reliability and high versatility. The valve rod is of anti blowout structure. The driving modes are diversified. The connecting dimensions of the valve stem, bracket and actuator conform to ISO5211 standard, and can be directly assembled with actuators of various specifications. The commonly used driving modes are manual, pneumatic, hydraulic, pneumatic hydraulic and electric, which improves the application performance of the double eccentric semi pneumatic ball valve.

When installing and using the pneumatic control valve, pay attention to the following aspects: the control valve is a field instrument, and the ambient temperature is required to be within - 25~60 ℃, and the relative humidity is 95%. If it is installed in the open air or at high temperature, waterproof and cooling measures shall be taken. Keep away from the vibration source or add anti vibration measures where there is a source; Generally, the regulating valve shall be installed vertically and can be tilted under special circumstances. If the tilt angle is too large or the self weight of the valve is too large, the valve shall be protected by supporting parts; Generally, the pipeline for installing the regulating valve should not be too high from the ground or the floor. When the pipeline height is more than 2m, a platform should be set as far as possible to facilitate the operation of the handwheel and maintenance; Before installation of control valve, the pipeline shall be cleaned to remove dirt and welding slag. After installation, in order to ensure that no impurities remain in the valve body, the valve should also be cleaned again, that is, all valves should be opened when the medium is introduced to prevent impurities from getting stuck. After using the hand wheel mechanism, it should be restored to the original neutral position; In order to enable the production process to continue in case of failure or maintenance of the control valve, the control valve should be equipped with a bypass pipeline. During the installation of pneumatic control valve, special attention shall be paid to whether the installation position of the control valve meets the requirements of the process.