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Causes Of Flange Leakage
What is the cause of flange leakage?
1. Reason for flange leakage: wrong mouth
The staggered seam means that the pipe and the flange are vertical, but the two flanges are not concentric, and the flanges are not concentric, so the surrounding bolts cannot freely penetrate the bolt holes. There is no other method, only reaming or small bolts are screwed into the bolt holes, which will reduce the tension of the two flanges, and the sealing surface of the sealing surface is also deviated, which is very easy to leak.
2. Reasons for flange leakage: Corrosion effect
Because the gasket is corroded by corrosive medium for a long time, the gasket undergoes chemical changes, the corrosive medium penetrates into the gasket, the gasket begins to soften, loses compressive force, and causes flange leakage.
3. Reasons for flange leakage: partial mouth
Eccentricity means that the pipeline and the flange are not perpendicular, not concentric, and the surface of the flange is not parallel. When the internal medium pressure exceeds the load pressure of the gasket, flange leakage will occur. This situation is mainly caused by installation or maintenance, and it is relatively easy to find. As long as the actual inspection is completed, the accident can be avoided.
4. Reason for flange leakage: opening
The opening is because the flange gap is too large. When the flange clearance is too large, causing external loads (such as axial loads or bending loads), the gasket will be impacted or vibrated, lose the compression force, and gradually lose the kinetic energy of the seal, resulting in failure.
5. Reasons for flange leakage: pressure
When installing flanges, it is more standard for two flanges to be butted together. However, in the system production, the temperature of the pipeline will change after entering the medium, which will cause the pipeline to expand or deform, so that the flange will be subjected to bending load or shear force, which will easily lead to the failure of the gasket.
6. Reason for flange leakage: wrong hole
Wrong hole means that the pipe and the flange are concentric, but the distance between the two bolts is greater than the bolt hole. The wrong hole will cause stress to the bolt, and the force cannot be eliminated, which will produce shear force on the bolt, and the bolt will break for a long time, resulting in seal failure.
7. Reasons for flange leakage: thermal expansion and contraction
Due to the thermal expansion and contraction of the fluid medium, and the expansion or contraction of the bolt, the gasket will have a gap, and the medium will leak through the pressure.
flange,Cause of leakage
There are four types of polishing methods for dual-phase steel flanges: manual, mechanical, chemical and electrochemical. The corrosion resistance and decoration of the flange can be improved by polishing. The existing stainless steel electropolishing solution still uses phosphoric acid and chromic anhydride. During the polishing and cleaning process, some chromium and phosphorus will be discharged into the waste water. pollution of the environment.
The shielding gas pressure of the butt welding flange is to avoid slight leakage of the butt welding flange. The shielding gas in the furnace should be connected to a certain positive pressure. Assuming that it is hydrogen shielding gas, it is generally required to be above 20kBar.
Welding spatter, iron filings, grease and other external impurities should be removed from the moving area of the probe. The flaw detection cousin should be flat and smooth to facilitate the free scanning of the probe. The surface roughness R.<6.3μm should be ground if necessary.
Contact F&D Flange Fittings
No.27 Gangqiang Road,Konggang Economic Zone,Yongxing Street,Longwan District,Wenzhou,China