All piping gaskets are designed to operate at their optimum on flange faces that are clean, free from scratches and indentations, flat, not distorted and have a gramophone surface finish between 125µ.ins to 250µ.ins. (3.2µ.M to 6.3µ.M).
Flange faces which have been subjected to crevice type corrosion attack at, or around, the inner portion of the flange sealing faces can occur over a period of time. In many field applications, the flange surface condition cannot be assessed until the bolted connection has been decommissioned and an inspection has determined the suitability of the flanges to accept the same type of gasket that was initially installed.
Depending on the extent of the flange face damage, the corroded surface may have extended onto the surface where gasket sealing element is seated and simply installing another gasket offers no guarantee the connection will remain tight and leak-free once the flange is commissioned back into service.
An assessment as to the suitabiliity of the flange surfaces has to be made in real-time with several options available:
The Defender™ RG Sealing Gasket has been designed to offer a tight and high integrity sealing solution for use on flange faces that have been subjected to erosion, corrosion, chemical attack and abrasion without having to modify or re-work the flange faces.