Installation of pipeline all welded pneumatic ball valve Installation requirements of all welded pneumatic ball valve The specification should use the correct way to lift the valve, because the overall weight of the valve is large, usually several tons, in order to protect the valve stem, do not attach the lifting chain to the handwheel, gearbox or actuator. The protective caps at both ends of the valve sleeve shall not be removed before welding, which can play a good role in protecting the internal parts of the valve body. Butt welding shall be adopted for the connection between the directly buried all welded pneumatic ball valve and the main pipeline. The circumferential welds connected by butt welding must be subject to nondestructive testing and radiographic inspection, and the inspection results must comply with the Radiography of Fusion Welded Joints in Disc Bending (GB3323 2005) Class II slice standard, one-time welding may be unqualified. In order to ensure that the second welding will not affect the use of pneumatic ball valve, the manufacturer should request the manufacturer to add a section of long sleeve tube at both ends of the valve when ordering the valve, and the length of the long sleeve tube should be reasonably determined according to the size of the valve diameter, Once the weld is unqualified, there is enough length to cut off the unqualified weld and re weld it to the pneumatic ball valve and pipeline, the valve should be in the 100% full open position to prevent the ball from being damaged by spattered welding slag. At the same time, ensure that the temperature of the valve's internal seals does not exceed 140 ℃, which will cause stress, and some parts may be deformed due to high temperature, If necessary, appropriate cooling measures can be taken to reasonably control the temperature during welding.

After years of development, the performance of electromagnetic flowmeter has been continuously improved and its function has gradually become stronger. There are also many types of excitation, such as DC excitation type, AC power frequency excitation type, dual frequency excitation type and low-frequency rectangular wave excitation type. It is an instrument for measuring the volume flow of conductive liquid based on the principle of Faraday's electromagnetic induction law.