Sealing Treatment on Flange Leakage
How to deal with the leak problem of flanges? Here we’d show you the sealing treatment method by case analysis.
A steam leak happened at the joint flange bolts of a DN150 valve body, with 400-500℃ leakage system temperature and 4MPA pressure. Due to the tiny connection space of flanges, it is impossible to infuse sealant directly through the space and eliminate leak.
In order to realize effective seal, we propose sealing treatment with fixtures and sealant after site investigation. Fixtures can wrap the leakage spot and form a seal chamber which can make it possible for us to inject sealant successfully.
1. The design of fixtures.
To build a seal chamber for the joint flanges
of valve flanges and pipeline flanges and wrap up the leakage spot. In case of another leakage happened at the dormant weak spot of valves and flanges caused by repressed pressure, we also make ring cavity and inject sealant at the space of fixtures and valve flanges.
During the infusing process for flanges with different sizes, tooth bridges should be applied to limit the fixture displacement.
2. The selection and dosage of sealant.
According to the temperature of leakage system and features of leakage spot, we use the TXY-18#A sealant. This kind of sealant has great temperature and medium resistance, and the performance of its injection is excellent. It is easy to build even and compact seal structure which can maintain stable for a long term.
According to the dosage estimate, each spot need 4.5KG sealant.
The inner dimension of fixtures is so small that we had to rap them to make tooth deformation and prevent from displacement. After infusion for the two cavities, we also infuse sealant to the intermediate space between them. It should be noticed that even pressure must be guaranteed during the process. The operator must focus on re-infusion and compaction all the time to guard against the stress relaxation.
After solidification, local re-infusion and compaction should be operated if it’s needed. Close the infusion hole in the end.