1. Side opening

Side opening refers to the fact that the pipeline is not perpendicular or concentric with the flange, and the flange surface is not parallel. When the internal medium pressure exceeds the load pressure of the gasket, flange leakage will occur. This situation is mainly caused during installation, construction, or maintenance, and is more easily detected. As long as a real inspection is carried out during the completion of the project, such accidents can be avoided.

2. Stagger

Stagger refers to a situation where the pipeline and flange are perpendicular, but the two flanges are not concentric. The flange is not concentric, causing the surrounding bolts to not freely penetrate the bolt holes. In the absence of other methods, the only option is to expand the hole or insert a smaller bolt into the bolt hole, which will reduce the tension between the two flanges. Moreover, there is a deviation in the sealing surface line of the sealing surface, which can easily lead to leakage.

3. Opening

Opening indicates that the flange clearance is too large. When the gap between flanges is too large and causes external loads, such as axial or bending loads, the gasket will be impacted or vibrated, losing its clamping force, gradually losing sealing energy and leading to failure.

4. Misfit

Wrong hole refers to the distance deviation between the bolt holes of the pipeline and the flange, which are concentric, but the distance deviation between the bolt holes of the two flanges is relatively large. Misalignment of holes can cause stress on bolts, and if this force is not eliminated, it will cause shear force on the bolts. Over time, it will cut the bolts and cause sealing failure.

5. Stress influence

When installing flanges, the connection between the two flanges is relatively standardized. However, in system production, when the pipeline enters the medium, it causes temperature changes in the pipeline, leading to expansion or deformation of the pipeline, which can cause bending load or shear force on the flange and easily lead to gasket failure.

6. Corrosion effects

Due to the long-term erosion of the gasket by corrosive media, the gasket undergoes chemical changes. Corrosion media seeps into the gasket, causing it to soften and lose its clamping force, resulting in flange leakage.

7. Thermal expansion and contraction

Due to the thermal expansion and contraction of the fluid medium, bolts expand or contract, resulting in gaps in the gasket and leakage of the medium through pressure.