A device comprises a bellows with protective rings arranged between corrugations of the bellows. Support rings are connected in a sealed manner to a gas line and a combustion chamber. A gimbal ring is positioned outside the bellows and via hinges is connected to structural brackets with support rings. A shield is mounted inside the bellows, the shield consisting of two cylindrical envelopes telescopically inserted one in another with a gap. The cylindrical envelopes are fixed in cantilever to support rings, forming a chamber which via channels for feeding a cooling working medium made in the support rings is connected to a main line for feeding the cooling working medium, and via the gap between the envelopes—to the cavity of the bellows unit. A housing is arranged outside the protective rings and adjoining them, and is made in the form of a metallic cylindrical helix, the ends of which are connected to the support rings (FIG. 2).