Witzenmann Gmbh Metallschlauch-fabrik Pforzheim

Witzenmann Gmbh

Tom Krawietz

Fabian Elsasser

Michael Pluschke

Fabian Els&auml;sser

A flexible conduit includes a corrugated tubular metal bellows having a minimum inner diameter; cylindrical end fittings secured to the bellows; a metal hose disposed coaxially within the bellows and having a maximum outer diameter which is less than the minimum inner diameter of the bellows; and a free annular cylindrical space situated between the bellows and the metal hose. The cylindrical space has an outer diameter equaling the minimum inner diameter of the bellows and an inner diameter equaling the maximum outer diameter of the metal hose. The conduit further has a hollow cylindrical knit wire element positioned in the cylindrical space. The knit wire element radially fully occupies the cylindrical space without projecting radially therefrom.

Flexible conduit having a cylindrical knit metal wire element

A hose with interlocked profile, particularly for automotive exhaust systems. The hose is helically stripwound from at least one single-layer or multi-layer metal strip, pre-formed to the shape of an S, with the edges of adjacent strip windings being interlocked with each other by the legs of the pre-form which have the aspect of the S-shaped hooks, and by folded end rims. The hose has radial embossed recesses which bring adjacent interlocked folded edges partially in direct contact with each other.

Hose with interlocked profile, particularly for automotive exhaust

A flexible conveying element, in particular for the exhaust systems of automotive combustion engines, having a helically or annularly corrugated metal hose which is installed coaxially in the metal bellows. The outside diameter of the metal hose is smaller than the inside diameter of the bellows and the ends of the hose are situated inside the end fittings of the bellows. The metal hose has an interlocked profile and the bellows and the hose are in an at least indirect contact with each other in at least one additional zone between the two end fittings.

Flexible conveying element

A tube element especially for exhaust systems and exhaust recirculation systems of combustion engines in vehicles which includes at least one helically or annularly corrugated bellows provided with cylindrical end fittings on each end of the bellows; a flexible hose made of metal and situated on an interior surface of the bellows; and a braiding hose made of metal wire which coaxially encloses an exterior surface of the bellows. The braiding hose being placed on the cylindrical end fittings together with the flexible hose so that the flexible hose and the braiding hose are connected firmly and at least indirectly. The braiding hose is installed in a state of pre-setting so that the braiding hose has a reduced radial cross-section which in frictional contact with the exterior surface of the bellows.

Tube element with one metal bellows

To reduce turbulence in a fluid flow, especially exhaust gas from automotive internal combustion engines, within a flexible conduit element, a bellows (1, 40, 42) has an internal hose (6) located therein made of woven or knit metal wire. The hose is engaged against the internal corrugations of the bellows (1) and/or a connecting pipe (41) between adjacent bellows (40, 42) to guide the exhaust gases, and dampen vibrations and oscillations, which may become resonant with the corrugations of the bellows, and thereby decrease noise level during the gas flow. The hose (6) is engaged against the inner corrugations (3) of the bellows by, for example, first axially compressing the hose to result in permanent deformation of the wires to a diameter larger than the clear inner diameter of the bellows; by then forcing the hose into the bellows, the hose will resiliently compress and engage against the bellows. The hose, at least at one point remote from an attachment stub (4) has the wires thereof circumferentially connected so that, upon axial compression, the hose will bulge in barrel shape. More than one connection (17, 18, 20-22) of the wires may be used. The frictional engagement force may be enhanced and controlled by additional internal force spreading elements, such as springs and the like, or by formation of pimples or small bulges embossed on the outside of the hose.

Growing community of inventors

Birkenfeld, Germany

Tom Krawietz