Flue gas/combustion air pipe system

摘要

The combined exhaust/combustion air pipe system (1) has a cap (8) that is releasably arranged at a control aperture (20). A radial projection portion (9) is provided at an exhaust tube (3) to provide radial spacing between an exhaust tube outer surface and an inner circumference surface (5) of an outer pipe (2). A bolt element (12) is located at the radial projection portion. The bolt element is connected with a through-hole (15) in the outer pipe. A fixing element (19) is provided at the bolt element for releasable fixation of the cap at the outer pipe.