Seal

摘要

A seal for the gap between two relatively rotatable machine parts (1, 2), in which at least one of the two mutually facing surfaces is provided with at least one deepened thread groove (3) having a conveying action pointing in the direction of the sealed-off space (4) and in which the thread groove (3) has arranged in front of it a preceding seal on the side facing away from the sealed-off space (4). The preceding seal comprises a ring magnet (5) which is brought up to a short distance from the opposite surface. In the gap (6) thereby formed, a ferrofluid is disposed, and the radial width of the gap corresponds to the distance of the threads arranged between the thread grooves (3) from the opposite surface. <IMAGE>