Abstract: A device for muffling the sound produced by a fluid in a duct, especially the sound produced in an intake pipe of a combustion engine, comprises a wall, whose inside defines a flow passage for the fluid. The device is at least partly tubular, i.e. it has two openings. At the outside of the wall (3) is arranged a plurality of chambers (4), each of which is connected to the flow passage via an aperture (7). The chambers (4) are bounded by the outside of the wall (3) as well as by bars (5, 6, 8) formed at the outside of the wall (3). The chambers (4) function in use as Helmholtz resonators. In addition, a device for the conduction of a fluid with the sound proofing device (1) described is presented.

Abstract: The lid for a tank of a fluid system such as a cooling water circuit of an automotive vehicle is characterized in that the lid is composed of an inner lid member which can be screwed to the neck of the tank, and of an outer lid member which covers the inner lid member in the manner of a bell or mushroom, and that a coupling means is formed between the inner lid member and the outer lid member, the coupling means containing a medium which below a predetermined temperature or a predetermined temperature range shows such a consistency that the medium establishes a non-rotational connection between the outer lid member and the inner lid member while the medium above the predetermined temperature or the predetermined temperature range assumes such a consistency that the outer lid member is rotatable relative to the inner lid member. It is thereby ensured that endangerment of persons by hot liquid or coolant steam squirting out therefrom is reliably prevented.