RADCOFLEX offers a complete range of fabric and metal expansion joints.
Where the medium to be conveyed is likely to include particles of rock, heavy dust, or flyash, RADCOFLEX highly recommends the inclusion of flyash seals or bolsters to help minimise the build-up of debris that could inhibit the expansion joint’s movement.
Flyash seals are selected depending on the system temperature and media, and are used in two basic configurations: the flyash seal and the bolster.
The flyash seal, which consists of a thin, flexible material such as fabric, wire mesh or high alloy metal sheet, is used in a variety of environments where a barrier is required around the entire perimeter of the expansion joint.
The bolster, which fills the entire cavity with a material less dense than flyash is commonly used on high temperature dry systems, or where flyash accumulation is only a problem on one side such as the bottom of a horizontal duct.
Liners and flyash seals are not leak-tight, and serve to minimise the build-up of flyash, rather than prevent it entirely. Minor ash or dust particles may penetrate, but usually not to a damaging degree.
The service life of the gas seal membrane and flyash seal depends on the severity of the media, materials of construction, and method of installation. Liners and flyash seals are introduced to help prolong the life of the gas seal membrane element. When the gas seal membrane is ultimately replaced, any accumulated flyash should be removed and a new flyash seal installed.