Installation of fully welded ball valves
(1) Hoisting. The valve should be hoisted in the correct way. To protect the valve stem, do not tie the hoisting chain to the handwheel, gearbox or actuator. Do not remove the protective caps at both ends of the valve sleeve before welding.
(2) Welding. The connection with the main pipeline is welded. The quality of the welding seam must meet the standard of “Radiography of Welded Joints of Disk Flexion Fusion Welding” (GB3323-2005) Grade II. Usually, one welding cannot fully guarantee all qualifications. Therefore, when ordering the valve, the manufacturer should ask the manufacturer to add 1.0m to both ends of the valve. Sleeve tube, once the welding seam is unqualified, there is enough length to cut off the unqualified welding seam and re-weld. When the ball valve and the pipeline are welded, the valve should be in the 100% fully open position to prevent the ball valve from being damaged by splashing welding slag, and at the same time ensure the valve The temperature of the inner seal does not exceed 140 degrees Celsius, and appropriate cooling measures can be taken if necessary.
(3) Valve well masonry. It adopts special structural design and has the characteristics of maintenance-free. Before burying, apply Pu special anti-corrosion coating on the outside of the valve. The valve stem is appropriately extended according to the depth of the ground, so that the staff can complete various operations on the ground. After the direct burial is realized, it is enough to build a small valve hand well. For conventional methods, it cannot be directly buried, and large valve wells need to be built, which results in a dangerous closed space, which is not conducive to safe operation. At the same time, the valve body itself and the bolt connection parts between the valve body and the pipeline will be corroded, which will affect the service life of the valve.
What should be paid attention to in the maintenance of the fully welded ball valve?
The point is that in the closed state, there is still pressurized fluid inside the valve body.
The second point is that before maintenance, first release the pipeline pressure and then keep the valve in the open position, then cut off the power or gas source, and then detach the actuator from the bracket, and only after all the above can be repaired.
The third point is to find out that the pressure of the upstream and downstream pipelines of the ball valve is really relieved, and then the disassembly and decomposition can be carried out.
The four points are to be careful in the process of disassembly and reassembly, to prevent damage to the sealing surface of the parts, to use special tools to remove the O-ring, and to tighten the bolts on the flange symmetrically and gradually and evenly during assembly.
Five points: When cleaning, the cleaning agent used should be compatible with the rubber parts, plastic parts, metal parts and working medium in the ball valve. When the working medium is gas, gasoline can be used to clean the metal parts, and For non-metallic parts, you need to use pure water or alcohol to clean. The decomposed single parts are cleaned by immersion washing, and the metal parts of the non-metallic parts that have not been decomposed are scrubbed with a clean and fine silk cloth soaked in cleaning agent, and all the grease adhering to the wall surface must be removed. , dirt and dust. Also, it cannot be assembled immediately after cleaning, and it can only be carried out after the cleaning agent has evaporated.
Post time: Aug-17-2022