Gaskets will leak after long-term use of the pipeline. When replacing the gasket, it is difficult to open the flange, and the simple self-made tool shown in Figure 8-6 can be used to force the two flanges apart.
1. The reason why the flange connection is not tight
The two connected flange sealing surfaces are not parallel;
Defects on the flange sealing surface;
After the pipeline is put into operation, the secondary tightening of the flange bolts is not carried out; Gasket failure: ① improper material selection; ② too thick gasket, punctured by high-pressure medium; ③ gasket wrinkled, cracked or broken; ④ gasket failure after long-term use;
After the pipeline is put into operation, the second tightening of the flange bolts is not carried out.
2. Elimination method
Hot bending the pipe on one side of the flange: On the side that needs to be bent, use an oxyacetylene flame to heat a strip surface with a length equal to 3 times the diameter and a width not greater than the radius, and then bend the pipe to make the flange sealing surfaces of the two countries parallel. ;
The pits, radial scratches, etc. with a depth of no more than 1mm shall be processed on a lathe; defects with a depth of more than 1mm shall be repaired by electric welding after cleaning the defect surface, and then cleaned, scraped or ground by hand;
After the pipeline is put into operation, when the temperature and pressure rise to a certain value, the bolts should be properly tightened, and the condition of the bolts should be checked frequently in the first few days after operation;
When replacing a new gasket, the gasket material should be selected according to the type and pressure of the medium; the gasket whose thickness meets the requirements; the gasket with qualified quality is modified; the new gasket is replaced regularly;
After the pipeline is put into operation, when the temperature and pressure rise to a certain value, the bolts should be properly tightened, and the tightening of the bolts should be checked frequently during the first few days of operation.
