Reasons for the loose connection of the manhole flange

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

The two flange sealing surfaces 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 retightened for 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) The flange bolts were not re-tightened after the pipeline was put into operation.