Flange joint consist of a couple of flanges,one gasket and several bolts & nuts.

First put gasket between two flanges’ mating sealing surfaces, after tighten the nuts connected to bolts, gasket surface will deform when the pressure increase to a certain value, so it can fill the gap between two flanges’ mating surfaces, prevent leakage from the flange joint.

Flange joint is detachble joint, it’s used for pipes connection. The flange types contains: intergral flange, lap joint flange, plate flange, slip on flange , weld neck flange , threaded flange.

Plate flange has weak rigidness, usally used in pressure less than 4Mpa occasion.

Weld neck flange (also called butt weld flange),have good rigidness, usally used in high pressure & temperature occasion.

The sealing suface types contains:

plate face : used in low pressure , non-toxic mediu pipeline.
raised face: used in high pressure occasion.
tongue-groove face: used in flammable , explosive , toxic media pipeline.