DE9416411U1 - Pipe, especially plastic pipe, and pipe connection from such pipes - Google Patents

Description

DIPPING. HORST ROSE DIPL.-ING. PETER KÖSCL · blPL'.-lNG/PSTER SOBISCH

PATENT ATTORNEYS AUTHORIZED BY THE EUROPEAN PATENT OFFICE - EUROPEAN PATENT ATTORNEYS

Patent Attorneys Rose, Kosel & Sobisch · Odastrasse 4a

Odastrasse4a, D-37581 Bad Gandersheim D-37581 Bad Gandersheim

Germany

Telephone (05382)4038 Telex957422siedpd Fax (05382)4030

YourRef. OurRef. Date

2464/38 11 October 1994

Karl Schöngen KG

DESCRIPTION

Pipe, in particular plastic pipe, and pipe connection made of such pipes

The invention relates to a pipe, in particular a plastic pipe, which has at least one end an end section along the pipe axis for forming a mechanical connection between several pipes, a sleeve for connecting such pipes and a pipe connection made of such pipes with or without such a sleeve.

Such pipes are usually used as empty or laying pipes for power and telecommunications cables and also for gas lines in the ground, especially for laying with so-called "soil rockets". This can, for example, substantial time and costs be saved when creating new house connections, because, for example, roads can be crossed under this way without

-2-PS/N

Bank account: NORD/LB, NL Bad Gandersheim (bank code 250 500 &oacgr;&ogr;&ggr;, ktöT^r. 22j 11&bgr;'^&ogr;&iacgr; ffcetgirekontfc: Postgiroamt Hannover (bank code 250100 30), account no. 66715-307

Oil to tear them up. Due to the special advantages, this type of installation has now become widespread.

Since the installation pipe is pulled into the ground by the earth-piercing rocket, the pipe string used with it must have a corresponding tensile strength. This could be achieved by using appropriately long one-piece pipes. However, such one-piece pipes are practically impossible to handle during transport to the construction site and before they are installed due to the required length, especially with larger diameters.

It has therefore become common practice to assemble the pipe string from a corresponding number of individual pipes in standardized lengths. The individual pipes, usually made of PVC, are welded or glued together. Water or gas tightness is not important here; the glued or welded points simply have to be designed in such a way that the ingress of soil or coarse dirt, which could lead to blockage of the pipe, is prevented.

It is known to use adhesive sleeves to connect the individual pipes. However, the usual adhesive sleeves lead to either the outer or inner wall of the pipe string having steps after assembly. This can lead to either the pipe string tearing when pulled into the ground or making it difficult to insert cables into the pipe string.

In order to obtain sufficient tensile strength of the adhesive or welded joint and to avoid steps inside or outside the pipe string, it is also known that such a pipe has an end section at its ends

-3-

Ol along the pipe axis to form a mechanical connection between several such pipes, whereby the end section has a notch over half the pipe cross-section of approximately the length of one to two pipe diameters to obtain a jointed adhesive or welding point. This creates a correspondingly long adhesive or welding joint in the direction of the pipe axis, so that the tensile forces in the pipe string can be transmitted as shear forces in the adhesive or welding joint.

The known methods for connecting pipes require qualified personnel on site. To produce welded joints, appropriate equipment with a power supply must be brought to the site.

It is therefore the object of the invention to further develop a pipe of the type mentioned at the outset in such a way that the production of a pipe connection is possible with or without a sleeve while avoiding the disadvantages described above.

The object is achieved according to the invention by a pipe with the features according to one of the appended claims to 4. The inventive design of the end section of a pipe of the type mentioned at the beginning makes it possible to produce a positive, tensile connection of such pipes simply by pushing them into one another. This avoids the costs of an adhesive and the additional work for qualified personnel, the pipe string can be assembled and laid in a much shorter time and the connection of the pipes is not affected by the weather conditions. In addition, the equipment required as an alternative to the adhesive for the production of welds

-A-

Oil connections are eliminated.

It is particularly expedient if the pipe according to the invention has an end section according to one of claims 1 or 3 at one end and an end section according to one of claims 2 or 4 at another end.

By using several such pipes, pipe strings of any length can be put together from any number of identical pipes particularly easily and without any additional aids such as couplings, etc., and with minimal production and storage costs during pipe production.

However, it can also be useful if a pipe has an end section according to one of claims 1 or 2 or 3 or 4 at each of its ends. Although either a corresponding sleeve or a pipe with corresponding counter-end pieces is then required to connect two pipes, this can be advantageous if several pipe strands frequently meet and need to be connected. Such pipes can also be used to connect pipe strands that meet, as previously described.

In order to be able to produce pipe strands with a substantially smooth inside and outside and without a change in cross-section, it is advantageous if the pipe according to one of claims 1 or 2 is characterized in that the wall thickness in the recessed area is substantially less than half the wall thickness in the area of the pipe adjacent to the end section, in particular in combination with a pipe according to one of claims 3 or 4, which is characterized in that the wall thickness in the recessed area is substantially more than half the wall thickness in the

-5-

Oi the area of the pipe adjacent to the end section is .

For particularly good durability of the connection between two pipes, it is best if the recessed area extends over the entire circumference of the pipe. This also makes assembly particularly easy because when two pipes are put together, no attention needs to be paid to the orientation of the pipes in relation to one another.

Particularly in the case of pipes with a non-circular, e.g. almost square, cross-section, it can also be useful if the recessed area only extends over part of the circumference of the pipe.

For a reliable connection of pipes according to the invention, it is advantageous if the pipe according to one of claims 1, 2, 7, 9, 10 is characterized in that the rib or the groove is arranged in the part of the recessed area adjoining the respective adjacent end of the pipe, in particular for combination with a pipe according to one of claims 3, 4, 8 to 10, which is characterized in that the rib or the groove is arranged in the part of the recessed area adjoining the respective adjacent end of the pipe.

For connecting two pipes with identical end sections, a sleeve with the features of the recessed area according to one of claims 1 to 4, adapted accordingly, is particularly suitable.

The advantages of the pipe according to the invention are particularly evident in a pipe which is pushed together by

-6-

Ol end sections of two previously described pipes or two pipes and a socket made pipe connection, in which the inner area has a lower bending stiffness about an axis transverse to the pipe axis than the outer area.

The pipe connection according to the invention has the particular advantage over the known pipe connections that it is not only easy to manufacture, but can also be separated and reassembled several times without causing any damage. This not only makes a cable accessible for repair purposes, for example, but branches can also be added later or the entire pipe string can be dismantled and reused elsewhere, for example when replacing it with one with a larger cross-section.

These advantages can be achieved particularly easily in terms of manufacturing technology if such a pipe connection is characterized in that the wall thickness of the respective inner region is substantially smaller ^than that of the respective outer region, in particular if the wall thickness of the respective inner region is substantially about 80% of the wall thickness of the respective outer region.

The invention will be explained in more detail below using embodiments shown in the drawings. For better visibility, the height of the rib, the depth of the groove and the wall thickness of the pipe are shown in the drawings partially not to scale. They show:

Fig. 1 a) to d) four different end sections of a pipe according to the invention;

-7-

Ol Fig. 2 a) to c) the production of a socketless pipe connection according to the invention;

Fig. 3 a) and b) a sleeve according to the invention and a pipe connection made with another sleeve according to the invention; and

Fig. 4 a) to d) the release of a pipe connection according to the invention.

In Fig. 1 a) a pipe 1 is shown, at one end 2 of which an end section 3 is arranged along the pipe axis 4. The end section 3 has a region 6 that is set back relative to an outer surface 5 of the pipe 1. In the part of the set-back region 6 that is remote from the end 2 of the pipe 1, a rib 7 is arranged that runs approximately transversely to the pipe axis 4, has a cross-section that rises in a ramp-like manner from the adjacent end 2 along the pipe axis 4 and whose side facing away from the adjacent end 2 is arranged essentially approximately perpendicular to the pipe axis 4.

The wall thickness of the pipe 1 produced in the recessed area 6 outside the rib 7 is approximately 44% of the wall thickness of the pipe 1 in the area of the pipe 1 adjacent to the end section.

In Fig. 1 b) a pipe 1 is shown with an end section 3, in which the area 6 is set back relative to an inner surface 11 of the pipe 1 and which has in its part of the set-back area 6 adjoining the end 2 a groove 9 running approximately transversely to the pipe axis 4, the end 2 of which

-8th-

·

• «

The side 10 facing the oil is arranged substantially approximately perpendicular to the tube axis 4.

The wall thickness of the pipe 1 produced in the recessed area 6 outside the groove 6 is approximately 54% of the wall thickness of the pipe 1 in the area of the pipe 1 adjacent to the end section.

The pipe 1 shown in Fig. 1 c) has in its one end section 3 a region 6 which is set back relative to an outer surface 5 of the pipe 1 and has a groove 9 running approximately transversely to the pipe axis 4, the side 10 of the groove 9 facing the adjacent end 2 being arranged essentially approximately perpendicular to the pipe axis 4. The wall thickness in the set-back region 6 outside the groove 9 corresponds to that of the pipe in Fig. 1 a).

The pipe 1 in Fig. 1 d) has a rib 7 pointing towards the pipe axis 4 in its recessed area 6 relative to the inner surface 11 in the part adjoining the end 2, as described for Fig. 1 a). The wall thickness in the recessed area 6 outside the rib 7 corresponds to that of the pipe in Fig. 1 b).

In order to form draft angles and to reduce the notch stresses in the area of the transition from the side 8 of the rib 7 to the recessed area 6 or from the side 10 of the groove 9 to the groove base, it can be advantageous if the side 8 of the rib 7 or the side 10 of the groove 9 is inclined by a few degrees relative to the pipe axis 4.

The height of the rib 7 and the depth of the groove 9 are in the

-9-

·

-9-

Ol figures are shown significantly exaggerated. In practical pipe designs it has been found that a rib height or groove depth of about 20-30% of the wall thickness in the recessed area 6 is appropriate.

Fig. 2 shows the production of a pipe connection between a pipe with an end section shown in Fig. 1 a) and a pipe with an end section shown in Fig. 1 b). First, the pipe with the end section according to Fig. 1 b) is pushed onto the pipe with the end section according to Fig. 1 a) until its end hits the ramp side of the rib (Fig. 2 a). As the pipes are pushed together further, the pipe with the end section according to Fig. 1 b) is elastically expanded in the area between the end and the groove (Fig. 2 b). For pipes according to the ones described in Fig. 1, the change in diameter is about 1-1.5%. If the pipes are pushed further together, the pipe with the end section according to Fig. 1 b) contracts again and the rib of the pipe with the end section according to Fig. 1 a) engages in the groove of the pipe with the end section according to Fig. 1 b) (Fig. 2 c). This creates a tensile, positive connection between the pipes, which meets the tightness requirements for empty or laying pipes for use in the ground.

Fig. 3 a) shows a sleeve 12 for connecting two pipes with end sections according to Fig. 1 b). The sleeve 12 consists of two end sections directly connected to one another according to Fig. 1 a). The sleeve 12 can also be imagined as a pipe with two end sections according to Fig. 1 a), where the distance between the end sections is zero.

Fig. 3 b) shows a sleeve 12

-10-

-10-

manufactured pipe connection of two pipes with end sections according to Fig. la).

With one socket 12 each according to Fig. 3 a) and Fig. 3 b), for example, a pipe extension by one socket length can be produced.

Using the end sections described in Fig. 1, any combination of such pipes with and without sockets can be produced directly or via extensions assembled from corresponding sockets.

The pipe sections can of course also be designed as branches or intersections and connecting shafts or distribution boxes with corresponding end sections can be integrated into a pipe string. For this purpose, pipe sockets with end sections can also be provided as welded parts, for example.

The very special advantage of the pipes and sleeves according to the invention and the pipe connections made from them compared to the prior art is that the pipe connections made from such pipes and/or sleeves can be separated and reassembled several times without causing any damage and with minimal effort.

The release of a pipe connection according to the invention between two pipes with end sections according to Fig. 1 a) and 1 b) is shown in Fig. 4. The wall thicknesses and the movement of the pipes relative to each other are shown greatly exaggerated for the sake of clarity. Starting from the joined, tensile pipe connection (Fig. 4 a), one of the two pipes is bent, e.g. by lifting the laid pipe string in the area of the pipe connection.

-11-

•11-

Ol In this case, the end of the tube with the end section according to Fig. 1 b) is elastically expanded in diameter at its end so that the rib 7 emerges from the groove 9. The gap 15 created between the outer surfaces 5 of the tubes is now fixed with a suitable tool, e.g. a blade 16 (Fig. 4 b).

By bending the pipe connection in the opposite direction, the rib 7 on the side opposite the blade 16 is disengaged from the groove 9 in the same way (Fig. 4 c).

Now the tubes can be pulled apart (Fig. 4 d).

The loosening is facilitated if the respective inner area 13 has a lower bending stiffness than the respective outer area 14 around an axis transverse to the pipe axis 4. If the pipes are made of the same material, this can be achieved by making the wall thickness of the respective inner area 13 substantially smaller than that of the respective outer area 14. In a pipe connection with end sections as shown in Fig. 1, the wall thickness of the respective inner area 13 is substantially about 80% of the wall thickness of the respective outer area 14.

Even if the invention is preferably suitable for use with plastic pipes, the advantages of the invention can also be used with pipes made of other materials when the dimensions are adapted to the material properties.

Claims (16)

DIPL.-ING. HORST ROSE DIPLrING. PETER KDSSL* DIPLrING.'PETER SOBISCH PATENT ATTORNEYS AUTHORIZED BY THE EUROPEAN PATENT OFFICE - EUROPEAN PATENT ATTORNEYS Patent Attorneys Rose, Kosel & Sobisch · Odastrasse 4a Odastrasse4a, D-37581 Bad Gandersheim D-37581 Bad Gandersheim Germany Telephone (05382)4038 Telex957422siedpd Fax (05382)4030 YourRef. OurRef. Date 2464/38 H- October 1994 Karl Schöngen KG EXPECTATIONS 1. Pipe (1), in particular a plastic pipe, which has an end section (3) along the pipe axis (4) at least at one end (2) for forming a mechanical connection between several pipes, characterized in that the at least one end section (3) has, at least on part of the pipe circumference, a region (6) which is set back relative to an outer surface (5) of the pipe (1) and has a rib (7) which runs approximately transversely to the pipe axis (4), which has a cross-section which rises in a ramp-like manner from the respective adjacent end (2) along the pipe axis (4) and whose side facing away from the respective adjacent end (2) (8) is arranged substantially approximately perpendicular to the tube axis (4). 2. Pipe (1), in particular plastic pipe, which is -2- Bank account: NORD/LB, NL Bad Gandersheim (bank code 250 500 OOJ.MS.-TCC 221 J8§70;ftj5Jgirokento: {"ostgiroamt Hannover (bank code 25010030), account no. 66715-307 -2- Ol at least one end (2) has an end section (3) along the pipe axis (4) for forming a mechanical connection between several pipes, characterized in that the at least one end section (3) has at least on part of the pipe circumference a region (6) which is set back relative to an outer surface (5) of the pipe (1) and has a groove (9) running approximately transversely to the pipe axis (4), wherein the side (10) of the groove facing the respective adjacent end (2) (9) is arranged substantially approximately perpendicular to the tube axis (4). 3. Pipe (1), in particular a plastic pipe, which has an end section (3) at at least one end (2) along the pipe axis (4) for forming a mechanical connection between several pipes, characterized in that the at least one end section (3) has at least on part of the pipe circumference a recess in relation to an inner surface (H) of the tube (1) has a region (6) which is set back and has a rib (7) which runs approximately transversely to the tube axis (4), which has a cross-section which rises in a ramp-like manner from the respective adjacent end (2) along the tube axis (4) and whose side (8) facing away from the respective adjacent end (2) is arranged substantially approximately perpendicular to the tube axis (4). 4. Pipe (1), in particular a plastic pipe, which has an end section (3) at at least one end (2) along the pipe axis (4) for forming a mechanical connection between several pipes, characterized in that the at least one end section (3) is arranged at least on a part of the pipe -3- -3- Oil circumference one opposite an inner surface (11) of the pipe (1) has a recessed region (6) with a groove (9) running approximately transversely to the pipe axis (4), wherein the side (10) of the groove (9) facing the respective adjacent end (2) is arranged essentially approximately perpendicular to the pipe axis (4). 5. Pipe (1), in particular a plastic pipe, which has an end section (3) according to one of claims 1 or 3 at one end (2) and an end section (3) according to one of claims 2 or 4 at another end. 6. Pipe (1), in particular a plastic pipe, which has at each of its ends (2) an end section (3) according to one of claims 1 or 2 or 3 or 4. 7. Pipe (1), in particular plastic pipe, according to one of claims 1 or 2, characterized in that the wall thickness in the recessed area (6) is substantially less than half the wall thickness in the area of the pipe (1) adjacent to the end section (3). 8. Pipe (1), in particular plastic pipe, according to one of claims 3 or 4, characterized in that the wall thickness in the recessed area (6) is essentially more than half the wall thickness in the area of the pipe (1) adjacent to the end section (3). 9. Pipe (1), in particular plastic pipe, according to one of the preceding claims, characterized in that the recessed area (6) extends over the entire -A- -4- Oil circumference of the pipe (1). 10. Pipe (1), in particular plastic pipe, according to one of claims 1 to 8, characterized in that the recessed region (6) extends only over a part of the circumference of the pipe (1). 11. Pipe (1), in particular plastic pipe, according to one of claims 1, 2, 7, 9, 10, characterized in that the rib (7) or the groove (9) is arranged in the part of the recessed area (6) remote from the respective adjacent end (2) of the pipe (1). 12. Pipe (1), in particular a plastic pipe, according to one of claims 3, 4, 8 to 10, characterized in that the rib (7) or the groove (9) is arranged in the part of the recessed area (6) adjoining the respective adjacent end (2) of the pipe (1). 13. Sleeve (12) for connecting pipes (1) according to one or more of the preceding claims with the features of the recessed area according to one of claims 1 to 4. 14. Pipe connection produced by pushing the end sections (3) of two pipes (1) according to one of the preceding claims or two pipes (1) and a sleeve (12) according to claim 13 into one another, in which the respective inner region (13) has a lower bending stiffness about an axis transverse to the pipe axis (4) than the respective outer region (14). 15. Pipe connection according to claim 14, characterized in that the wall thickness of the respective inner -5- -5- Oil area (13) is substantially lower than that of the respective outer area (14). 16. Pipe connection according to claim 15, characterized in that the wall thickness of the respective inner region (13) is essentially about 80% of the wall thickness of the respective outer region (14).