Corrugated tube with external protective film

Abstract: This invention concerns a flexible tube in plastic material consisting of a corrugated wall (11), made up of a succession of alternating crests and hollows, and a possible smooth internal lining (14). The corrugated tube is furnished with an external protective sheath (15) in plastic material, which tightly envelopes the corrugated wall (11) and is removable, even only partially, to give access from the outside to the hollows of said corrugated wall.

Description: Field of the invention This invention concerns flexible plastic tubes which have a uniformly corrugated external wall, with a possible internal lining, designed for use in plumbing systems. State of the art There already exist plastic tubes, which are corrugated and flexible, for the passage of fluids, for example in the waste discharge of plumbing systems. However, the plastic material from which they are made is sensitive to ultraviolet rays. These tubes, therefore, are subject to deterioration both structurally and aesthetically when the tubes are stocked and/or remain exposed to the light. Furthermore, the external corrugation of the tube favours the accumulation of dirt between the ridges, as well as penetration by cement and other materials, leading to possible deformation of the tube when it is laid in position. On the other hand, as is already known, for example with the publication of patent n. DE-U-297 06 044, there is a plastic tube with three walls, where the internal wall is smooth, the intermediate wall corrugated and the external wall is smooth, where all three walls are coextruded and tightly fastened together. In other words, in such a tube, where all the walls are essentially welded together, the external wall is not removable whenever it is necessary to have access to the corrugated wall of the tube, nor is there any mention in the above-mentioned publication of how said external wall may be removed. Purpose and Overview of the invention One aim of this invention is to resolve the above inconveniences, protecting the corrugated tubes externally by means of a film, so that the outward-facing grooves are closed. This aim is achieved, in accordance with the invention, by applying an external removable protective sheath to a flexible corrugated tube in accordance with claim 1. As the external protective sheath may be tubular and extruded together with the corrugated tube, but without being intimately bound together, it can be removed partially or totally, as required. In this way, the corrugated tube will come to have a cross-section in three layers, or three walls, with the most external being removable. To allow the coextrusion with the tube, but leaving the sheath removable, the latter is made from a plastic material which is not compatible with that forming the corrugated wall of the tube and, therefore, not weldable with such a corrugated wall during the course of coextrusion. In any case, with an appropriate choice of material for the external protective sheath, the tube will be protected against ultraviolet rays and, particularly, against penetration and deposit of dirt or cement within the grooves, preventing potential deformation, too. In addition, at least part of the lining sheath may be removed at any time, as needed, when the tube is used. Brief description of the drawings The invention will be explained in further detail below, with reference to the enclosed drawings, which are indicative but not binding, and in which: Fig. 1 shows part of a flexible corrugated tube with three layers, that is, with a coextruded external protective sheath. Detailed description of the invention The flexible corrugated tube 10 shown in the drawings is, in itself, already known. It usually has one wall 11 which is uniformly corrugated or ridged, with a succession of hollows or grooves 12 that alternate with crests 13, and a smooth internal lining 14. Externally, the corrugated tube 10 is furnished with a protective sheath 15 which covers the corrugated wall 11, obstructing the hollows or grooves 12 that face outwards from the tube. The external protective sheath 15 may be coextruded with the corrugated wall 11 and the internal lining 14. Said external sheath 15 is made in a plastic material that is different from and not compatible with the plastic material used for the corrugated wall, in order not to be welded with the latter, but adhering separately to the crests 13. The resulting tube is therefore protected by the external sheath against ultraviolet rays and against penetration of material into the hollows or grooves 12. However, the tube may also be easily peeled along certain sections, as required, in order to gain access to any of its external part, for the fastening of complementary components or supplementary pieces, as foreseen in certain assembly systems. This is also possible after the tube has been laid in place. Also, the sheath may have, as necessary, different colours that help identify the tube being protected and help determine, just by sight, the sector and the end use of the tube itself.

Claims: A flexible tube suitable for the passage of fluids, comprising a corrugated wall of a first plastic material, formed by a succession of alternating crests (13) and hollows (12) and preferably having a smooth internal lining and provided with an external protective sheath of a plastic material, wherein said external protective sheath is of a second plastic material different from the first plastic material and which is not compatible or weldable with this said first material forming said corrugated wall; said external protective sheath is coextruded on the corrugated wall so as to contact the crests and tightly envelope the corrugated wall thereby forming an enclosed space in the hollows between the crests; and said external sheath is partially removable such that the access to the enclosed space in any hollow is possible from the outside.

Inventors: BONOMINI COSTANTINO, BONOMINI, COSTANTINO
Applicants: EUREKA IMMOBILIARE S R L, EUREKA IMMOBILIARE S.R.L.
Application year: 2001
Main classification: F16L9
IPC codes: F16L11, B29C47, B29C63