What Factors Affect the Sealing of the Pressure Vessel Flange?

Pressure vessel flange sealing in use will be due to bolt preload, gasket sealing performance, flange sealing surface characteristics, flange stiffness and operating conditions and subject to certain effects, we Jetvision share something with you.

1.Bolt preload force

The appropriate preload force can ensure that the gasket in the work can also retain a certain sealing ratio pressure, preload force is too large will crush the gasket or extrusion, thereby destroying the seal. The distribution of the preload on the gasket also affects the sealing performance. The way to ensure an even distribution of the preload is to increase the number of bolts under the condition that the space required for fastening and removing the bolts is met.

2.Gasket sealing performance

The gasket is an important component of the seal. Suitable gasket material, to reflect the gasket in the appropriate preload force under the action of both the necessary elastic deformation, and not to be crushed or extrusion. The distance between the flange sealing surfaces is stretched during work, and the gasket material should have sufficient resilience to bring the gasket surface into close contact with the flange surface to continue to maintain good sealing performance.

3.Characteristics of flange sealing surface

The type and surface performance of the flange sealing surface play a vital role in the sealing effect. Concave and convex surfaces and tongue and groove surfaces should be used for more stringent working conditions. The flatness of the flange sealing surface, the centerline and perpendicularity of the sealing surface and the flange directly affect the uniformity of the force on the gasket and the good contact between the gasket and the flange. The surface roughness of the sealing surface of the flange should be compatible with the requirements of the gasket, and the surface should not allow radial knife marks or scratches, let alone the existence of surface cracks.

4.Flange stiffness

Insufficient stiffness will make the flange produce excessive warpage deformation, resulting in sealing failure. Many factors affect the stiffness of the flange, which increases the thickness of the flange, increase the outer diameter of the flange and other methods can improve the stiffness of the flange, reduce deformation, so that the bolt force is uniformly transferred to the gasket, to obtain a uniform and sufficient sealing pressure, while improving the seal. Reduce the force arm of the bolt force, can reduce the bending moment of the flange, conducive to sealing.

5.Operating conditions

Pressure vessel flange operating temperature, pressure and chemical and physical properties of the medium also affect the reliability of the flange connection. Temperature increases, the medium viscosity becomes smaller, the tendency of leakage increases; high temperature so that the medium chemical and physical activity increases, resulting in corrosion and dissolution of the gasket and flange; high temperature can also make the cuttlebone, flange and gasket creep and stress relaxation.