PIPE SYSTEM

Abstract: A pipe system with an inner pipe segment (1) and an outer pipe segment (2) is described, the inner pipe segment (1) being fitted in the interior of the outer pipe segment (2) and being fixed thereto. The inner pipe segment (1) is provided with at least one substantially radially directed fixing lug (20) with a free end (21). The outer pipe segment (2) is provided with at least one guide groove (40) for receiving and guiding the free end (21) of the fixing lug (20), so that the mounting of the inner pipe segment (1) in the outer pipe segment (2) is facilitated.

Description: Title: Pipe system The present invention relates to a pipe system, comprising an inner pipe segment and an outer pipe segment, in which the inner pipe segment has smaller transverse dimensions than the outer pipe segment and is fitted with radial clearance in the interior of the outer pipe segment, in which the inner pipe segment is fixed to the outer pipe segment, and in which at least one of the abovementioned pipe segments is provided with at least one substantially radially directed fixing lug. Such pipe systems comprising an inner pipe segment and an outer pipe segment are known in practice and are used, for example, as a component of a flue duct/air supply system of a heating appliance such as a heating boiler and the like. The inner pipe segment and the outer pipe segment are generally disposed concentrically relative to each other in this case. In the case of such known pipe systems the inner pipe segment is provided with two fixing lugs, which are of substantially equal length and are situated diametrically opposite each other. The outer pipe segment in this case is provided with two holes, the radial positions of which correspond to the radial positions of the fixing lugs on the inner pipe segment. The inner pipe segment is then mounted in the outer pipe segment by means of screws that are inserted from the outside through the holes in the outer pipe segment into the fixing lugs on the inner pipe segment, and are then tightened therein. A problem that occurs during the mounting of the known pipe systems is that it is a cumbersome and time-consuming process to position the inner pipe segment in such a way relative to the outer pipe segment that the holes in the outer pipe segment and the fixing lugs on the inner pipe segment are aligned with each other. A further problem of the known pipe systems is that it is necessary to use screws for fixing the inner pipe segment to the outer pipe segment . An object of the present invention is to provide a new pipe system with an inner pipe segment and an outer pipe segment in which the abovementioned problems are eliminated or at least lessened. According to an important aspect of the present invention, the positioning of an inner pipe segment relative to an outer pipe segment is simplified by the fact that in the case of a pipe system comprising an inner pipe segment and an outer pipe segment, one pipe segment of which is provided with at least one fixing lug, the other pipe segment is provided with a guide groove comprising an inlet end and a positioning end, for receiving and guiding the free end of the abovementioned fixing lug. If in the case of a pipe system according to the invention the inner pipe segment is provided with a fixing lug, the outer pipe segment is provided with a guide groove. Said guide groove extends from an inlet end at one end of the outer pipe segment to a positioning end in the interior of the outer pipe segment. The pipe system according to the invention is mounted by sliding the inner pipe segment into the outer pipe segment, the free end of the fixing lug being slid into the inlet end of the guide groove. During further sliding of the inner pipe segment into the outer pipe segment the fixing lug is forced by the guide groove towards the positioning end into the interior of the outer pipe segment, where the guide groove has a stop, so that further sliding of the fixing lug is prevented. The position of said stop is selected in such a way that the inner pipe segment assumes the intended position relative to the outer pipe segment when the fixing lug has reached said stop. In this case the sliding of the free end of the fixing lug into the guide groove is a simple process, owing to the fact that the mouth of the guide groove is situated at one end of the outer pipe segment. The result of all this is that during the mounting of a pipe system according to the invention the positioning of the inner pipe segment relative to the outer pipe segment is very simple. This aspect of the invention is already useful in constructions in which the fixing is carried out by means of screws, as is the case in the pipe systems known in practice. A further advantage is obtained if a snap connection can be produced between the inner pipe segment and the outer pipe segment, because fixing of the inner pipe segment to the outer pipe segment is then achieved at the same time. The snap connection can be produced by a fixing lug of one pipe segment being able to snap into a recess of the other pipe segment. A screw can also still be used here, if desired. The abovementioned and other aspects, features and advantages of the present invention will be clarified further by the description that follows of a preferred embodiment of a pipe system according to the invention with reference to the drawing, in which identical reference numerals indicate identical parts, and in which: Figure 1 is a longitudinal section of an inner pipe segment according to a preferred embodiment of the invention; Figure 2 is a view from the front of the inner pipe segment shown in Figure 1; Figure 3 is a longitudinal section of an outer pipe segment according to a preferred embodiment of the inven ion; Figure 4 is a front view of the outer pipe segment shown in Figure 3; Figure 5 is a longitudinal section of a fixing lug according to a preferred embodiment of the invention; Figure 6 is a longitudinal section of a part of the outer pipe segment and the fixing lug according to a preferred embodiment of the invention, in the mounted state. Figures 1 and 2 show an inner pipe segment according to a preferred embodiment of the invention, indicated in its entirety by reference numeral 1. The inner pipe segment 1 has an inner pipe wall 11 with an inner surface 12 and an outer surface 13. The inner pipe segment 1 can be of any desired shape. In this example the inner pipe segment 1 is a bend segment . At least one radially directed fixing lug 20 is situated on the outer surface 13. The free end of the fixing lug 20 is indicated by reference numeral 21. The number of fixing lugs 20 is not critical; in the example shown there are two fixing lugs 20. The fixing lugs 20 can be fitted in any desired positions on the outer surface 13. In the case of this preferred embodiment the fixing lugs 20 are situated diametrically opposite each other and are at a substantially equal axial distance relative to a first end 14 of the inner pipe segment 1. A second end of the inner pipe segment 1 is indicated by the reference numeral 15. The inner pipe segment 1 is preferably made of plastic by means of, for example, injection moulding, but it can also be made of another material, for example of metal. Figures 3 and 4 show an outer pipe segment according to a preferred embodiment of the invention, indicated in its entirety by reference numeral 2. This illustrated outer pipe segment 2 is designed to contain the inner pipe segment 1 shown in Figures 1 and 2. The transverse dimensions of the outer pipe segment 2 are therefore greater than the transverse dimensions of the inner pipe segment 1. The outer pipe segment 2 can further be shaped in any desired manner, provided that the shape of the outer pipe segment 2 does not prevent insertion of the inner pipe segment 1. Not only the transverse dimensions, but also the axial dimensions of the inner pipe segment 1 and the outer pipe segment 2 may differ from each other. The outer pipe segment 2 has an outer pipe wall 16 with an inner surface 17 and an outer surface 18. At least one guide groove 40 is provided in the inner surface 17 of the outer pipe wall 16, which groove extends in the axial direction from a first or inlet end 41 at a first end 19 of the outer pipe segment 2 to a second or positioning end 42 in the interior of the outer pipe segment 2. The number of guide grooves 40 on the outer pipe segment 2 can be equal to or greater than the number of fixing lugs 20 on the inner pipe segment 1, but this is not essential. It is quite possible to position the inner pipe segment 1 correctly relative to the outer pipe segment 2 by, for example, moving only one fixing lug 20 into only one guide groove 40. Fewer guide grooves 40 than fixing lugs 20 can therefore be used. There are two guide grooves 40 in the example shown. Since both guide grooves 40 are designed for receiving a fixing lug 20, the tangential positions of the guide grooves 40 correspond to those of the fixing lugs 20, and in this example they are therefore situated diametrically opposite each other. It can be seen clearly in Figure 3 that in the embodiment shown the guide groove 40 tapers in the direction from the inlet end 41 towards the positioning end 42, in other words, has a decreasing tangential width. The positioning end 42 is provided with a stop, which in this example is formed by a part of the inner periphery of a hole 45 provided in the radial direction in the guide groove 40. In another conceivable embodiment the stop can be formed by providing the guide groove 40 with a recess in the bottom at the positioning end 42. The hole 45 is designed to receive the free end 21 of the fixing lug 20. The shape of the hole 45 is therefore related to the transverse contour of the free end 21 of the fixing lug 20. If the transverse contour of the free end 21 is substantially circular, the hole 45 will likewise be substantially circular. In the case of the illustrated embodiment of the outer pipe segment 2 the guide grooves 40 are provided in the outer pipe wall 16, which is provided with thickened parts 43 for this purpose. If the outer pipe wall 16 itself is sufficiently thick, in other words, if the radial dimensions of the outer pipe wall 16 are sufficiently large, the thickened parts 43 can, of course, be omitted. Again, if the guide groove 40 is provided on the inner surface 17 of the outer pipe segment 2, for example by providing two elevations running substantially parallel to each other on the inner surface 17, in which case the guide groove 40 is then situated between these two elevations, the thickened parts 43 can be omitted. The outer pipe segment 2 is preferably made of metal, but it can also be made of another material, for example of plastic. Figure 5 shows a longitudinal section of the fixing lug 20. The fixing lug 20 can be of any desired shape, the condition that has to be met being that the fixing lug 20 must bridge the radial distance between the outer surface 13 of the inner pipe segment 1 and the inner surface 17 of the outer pipe segment 2. The fixing lug 20 is of a circular cylindrical shape in this example. The free end 21 of the fixing lug 20 is preferably tapered, as shown in Figure 5. The shape of the free end 21 of the fixing lug 20 and the shape of the hole 45 must in any case be matched to each other, so that in the mounted state the free end 21 connects to the inner circumference of the hole 45, with the result that the hole 45 is sealed. It is also possible to use a fixing lug 20 whose free end 21 is not tapered, for example if the free end 21 does not have to fulfil any sealing function. This is the case, for example, if there is no hole 45 in the outer pipe segment 2, but a recess is provided in the bottom of the guide groove 40, for receiving the free end 21 of the fixing lug 20. The fixing lug 20 shown in Figure 5 is provided with a bore 22 for receiving, for example, a screw or a nail, in order to ensure that in the mounted state the inner circumference of the hole 45 connects well to the tapered free end 21 of the fixing lug 20. The screw or nail can also be used to secure the connection between the inner pipe segment 1 and the outer pipe segment 2. The bore 22 can be provided with screw thread for receiving a screw. The fixing lug 20 can be of a solid design if, for example, such securing is not necessary. Figure 6 shows a part of the outer pipe segment 2 with the guide groove 40 and the fixing lug 20, the free end 21 of which is situated in the hole 45 in the outer pipe segment 2. It can be seen in this figure that a bottom 48 of the guide groove 40 slants upwards in the direction of the positioning end 42. The inner pipe segment 1 shown in the figures is mounted in the manner described below in the interior of the outer pipe segment 2 shown in the figures . The inner pipe segment 1 is slid with its second end 15 into the outer pipe segment 2, from the first end 19 thereof. If the fixing lugs 20 on the inner pipe segment 1 are situated at the first end 19 of the outer pipe segment 2, the inner pipe segment 1 is positioned and moved relative to the outer pipe segment 2 in such a way that the free ends 21 of the fixing lugs 20 are received by the inlet ends 41 of the guide grooves 40. If a concentric arrangement of the inner pipe segment 1 relative to the outer pipe segment 2 is envisaged, the fixing lugs 20 must have radial dimensions that are substantially equal to each other. It is advantageous if the inlet ends 41 of the guide grooves 40 have a tangential width that is greater than the tangential width of the fixing lugs 20, in order to facilitate the insertion of the guide lugs 20 into the guide grooves 40. The inner pipe segment 1 is then slid further into the outer pipe segment 2, the fixing lugs 20 being forced in the direction of the holes 45 by the guide grooves 40. In this case the guide grooves 40 preferably taper in the direction from the inlet end 41 towards the positioning end 42, as shown in Figure 3. The slanting of the bottom 48 of the guide grooves 40 shown in Figure 6 is advantageous here, because as a result of it an elastic deformation will occur in the inner pipe wall 11 and/or the outer pipe wall 16, depending on their rigidity. In this example the inner pipe segment 1 is made of plastic, and the outer pipe segment 2 is made of metal, so that the inner pipe wall 11 can be pressed inwards and can spring out again. The tangential width of the positioning ends 42 of the guide grooves 40 is advantageously equal to the tangential width of the guide lugs 20, in order to force the guide lug 20 into the intended position when the free ends 21 of the fixing lugs 20 have reached the positioning ends 42. The free ends 21 then fall into the holes 45, and the inner pipe wall 11 moves outwards again. The inner pipe segment 1 and the outer pipe segment 2 are then connected to each other. This is already the case if at the positioning end 42 the guide groove 40 is provided with a recess in the bottom 48, instead of a hole 45. However, a hole has the advantage over a recess that it can be made more easily. If desired, a nail, screw or the like can be provided in the bores 22 of the fixing lugs 20, in order to give additional security to the connection between the inner pipe segment 1 and the outer pipe segment 2. In the example described a form-fit connection is produced between inner pipe segment 1 and outer pipe segment 2, as a result of the slanting of the bottom 48 of the guide groove 40 and the elastic deformability of the inner pipe wall 11 and/or the outer pipe wall 16. At least one of the inner pipe wall 11, the outer pipe wall 16 and the fixing lug 20 is preferably made elastically deformable, so that a form-fit connection can result between inner pipe segment 1 and outer pipe segment 2. If two fixing lugs 20 situated diametrically opposite each other according to the example described are used, in the mounted state the inner pipe segment 1 can be moved relative to the outer pipe segment 2. The inner pipe segment 1 can then in fact be rotated about a tilting line that coincides with the axes of the fixing lugs 20. In order to prevent such a movement, radially directed distance pieces 30 can be fitted on the outer surface 13 of the inner pipe segment l, as shown in Figures 1 and 2. The number of distance pieces 30 is not critical; in the example shown there are two distance pieces 30. The distance pieces 30 can be fitted in any desired positions on the outer surface 13. In the case of this preferred embodiment the two distance pieces 30 are situated diametrically opposite each other, and they are at a substantially equal axial distance from the second end 15 of the inner pipe segment 1. In the case of the illustrated embodiment of the inner pipe segment 1 the tangential positions of the fixing lugs 20, on the one hand, and the distance pieces 30, on the other hand, differ from each other. If there is a concentric arrangement of the inner pipe segment 1 relative to the outer pipe segment 2, as is the case in this example, the radial dimensions of the distance pieces 30 must be substantially equal to each other. The distance pieces 30 are preferably fitted on a line that in the tangential direction is at right angles to the abovementioned tilting line. Again, if one fixing lug or more than two fixing lugs 20 are used, the distance pieces 30 can be used to support the inner pipe segment 1 at certain positions on the outer pipe segment 2, so that the position of the inner pipe segment 1 can be fixed relative to the outer pipe segment 2. Freedom of rotation of the inner pipe segment 1 relative to the outer pipe segment 2 can also be prevented by the use of three or more fixing lugs 20. It will be clear to the person skilled in the art that the scope of the present invention is not restricted to the examples discussed above, but that various changes and modifications thereof are possible without deviating from the scope of the invention as defined in the appended claims. For instance, the pipe segments illustrated have a substantially circular transverse contour, but they could also have, for example, a square transverse contour. It is not necessary here for the transverse contours of the various pipe segments to be the same shape. The pipe segments shown are bend segments, but they could also be another shape and be, for example, straight. Moreover, in the description above it is stated, for example, that the fixing lugs 20 are provided on the inner pipe segment 1, with the guide grooves 40 being provided on the outer pipe segment 2. It is also conceivable within the scope of the present invention for the inner pipe segment 1 to be provided with the guide grooves 40 and for the outer pipe segment 2 to be provided with the fixing lugs 20. The distance pieces 30 shown can be used not only in the case of pipe systems according to the invention, but also in the case of the known pipe systems . In the example described the distance pieces 30 are fitted on the outer surface 13 of the inner pipe segment 1, but they can also be fitted on the inner surface 17 of the outer pipe segment 2.

Claims: CLAIMS 1. Pipe system, comprising an inner pipe segment (1) and an outer pipe segment (2) , in which the inner pipe segment (1) has smaller transverse dimensions than the outer pipe segment (2) and is fitted with radial clearance in the interior of the outer pipe segment (2) , in which the inner pipe segment (1) is fixed to the outer pipe segment (2) , in which at least one of the abovementioned pipe segments (1) is provided with at least one substantially radially directed fixing lug (20) , and in which the other pipe segment (2) is provided with a guide groove (40) comprising an inlet end (41) and a positioning end (42) , for receiving and guiding a free end (21) of said fixing lug (20) . 2. Pipe system according to claim 1, characterized in that the tangential width of the guide groove (40) at the inlet end (41) is greater than the tangential width of the guide groove (40) at the positioning end (42) . 3. Pipe system according to claim 1 or 2, characterized in that at the positioning end (42) the guide groove (40) is provided with a recess in a bottom (48) , for receiving the free end (21) of the fixing lug (20) . 4. Pipe system according to claim 1 or 2, characterized in that at the positioning end (42) the guide groove (40) is provided with a hole (45) for receiving the free end (21) of the fixing lug (20) . 5. Pipe system according to claim 4, characterized in that the at least one fixing lug (20) is provided with a bore (22) . 6. Pipe system according to any of the preceding claims, characterized in that the radial depth of the bottom (48) of the guide groove (40) varies in the axial direction in such a way that the bottom (48) of the guide groove (40) slants upwards in the direction from the inlet end (41) towards the positioning end (42) . 7. Pipe system according to claim 6, characterized in that at least one of the inner pipe segment (1) , the outer pipe segment (2) and the fixing lug (20) is elastically deformable, the fixing lug (20) having such radial dimensions that the fixing lug (20) with its free end (21) connects to the bottom (48) of the guide groove (40) when the fixing lug (20) is moved relative to the guide groove (40) . 8. Pipe system according to any of the preceding claims, characterized in that the guide groove (40) is provided in a thickened part (43) of a wall (16) of the abovementioned other pipe segment (2) . 9. Pipe system according to any of the preceding claims , characterized in that at least one of the pipe segments (1) is provided with at least one substantially radially directed distance piece (30) . 10. Pipe system according to any of the preceding claims, characterized in that the at least one fixing lug (20) is circular cylindrical at any rate at its free end (21) , the free end (21) preferably being tapered. 11. Pipe system according to any of the preceding claims, characterized in that the inner pipe segment (1) and the outer pipe segment (2) are concentric bend segments. 12. Pipe system according to any of the preceding claims, characterized in that the at least one fixing lug (20) is provided on the inner pipe segment (1) , and in that the guide groove (40) is provided on the outer pipe segment (2) , the inner pipe segment (1) preferably being provided with two fixing lugs (20) , situated diametrically opposite each other. 5 13. Outer pipe segment (2), designed to contain an inner pipe segment (1) with at least one radially directed fixing lug (20) and to be fixed thereto, comprising at least one guide groove (40) for receiving and guiding said fixing lug 0 (20) , the at least one guide groove (40) having a stop, preferably in the form of a part of an inner circumference of a hole (45) or of a recess in a bottom (48) of the guide groove (40) . 5 14. Inner pipe segment (1), designed to be inserted into an outer pipe segment (2) with at least one radially directed fixing lug (20) and to be fixed thereto, comprising at least one guide groove (40) for receiving and guiding said fixing lug (20) , the at least one guide groove (40) having a stop, Q preferably in the form of a part of an inner circumference of a hole (45) or of a recess in a bottom (48) of the guide groove (40) .

Inventors: NOORLANDER HANS NICOLAAS, WILLEMSE PETRUS JOHANNES, NOORLANDER, HANS, NICOLAAS, WILLEMSE, PETRUS, JOHANNES
Applicants: INTERACTIVE BOUWPRODUCTEN B V, INTERACTIVE BOUWPRODUCTEN B.V.
Application year: 2001
Main classification: F16L9
IPC codes: F16L9, F16L43