A hollow roller or drying cylinder (2) to be rotated and to be heated as a consequence of burning fuel gas within the drying cylinder so that web material such as paper or textile material is subjected to drying heat on coming into contact with an outer surface of the cylinder (2). The cylinder (2) comprises a cylindrical heat conducting wall (4) of metal. A ribbon burner (24) for burning fuel gas supplied thereto (mixed with combustion air) through pipes (20, 22) is mounted inside the cylinder (2) and has a burner slot (26) facing towards and adjacent to an inner surface (28) of the cylinder (4). An acoustic baffle (64) to absorb sounds generated by the combustion of the fuel gas is mounted behind the burner (24) at an opposite side of the axis of rotation of the cylinder (2) to the side on which the burner is disposed. The baffle (64), which extends longitudinally of the drying cylinder (2), can comprise porous layers (66, 68) of ceramic fibres.
