Reasons for Loose Flange Connection at Manhole

After long-term use, the gasket may leak. When replacing the gasket, it's difficult to open the manhole flange. A homemade simple tool can be used to forcefully separate the two flanges.

The sealing surfaces of the two flanges connected are not parallel.

(2) Defects on the manhole flange sealing surface

(3) After the pipeline was put into operation, the flange bolts were not tightened a second time.

(4) Gasket Failure: ①Improper material selection; ②Gasket too thick, pierced by high-pressure medium; ③Gasket with wrinkles, cracks, or breaks; ④Gasket fails after long-term use.

5) After the pipeline was put into operation, the flange bolts were not re-tightened.