Patent ID: 6862852

Claim:
A system comprising a cylindrical tube having a passageway therethrough, the tube constructed of a material that is capable of deformation under the influence of a temperature increase, and a gasket forming a collar around the tube, said gasket being made of a fire-retardant material with a base of a cross-linkable material and an expandable material, whereby the said gasket is constructed and arranged to expand after the plasticizing point of the tube is reached and to such an extent that the tube is compressed substantially closing the passageway and a medium-tight seal of a lead-through housing and the tube is obtained, characterized in that said tube is made of a plastic or a composite material and in that the gasket has a base of a rubber material containing 2-25% by weight of graphite, wherein said gasket is in the form of a plug for being sealingly inserted into a circular space that is formed between a lead-through housing coaxial with the tube and the tube that extends therethrough.