DE29600382U1 - Pipe coupling - Google Patents

Description

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EUROPEAN PATENT ATTORNEY

VNR: 100 307

H. BAUER · AM KEILBUSCH 4 · D-52080 AACHEN

Utility model application

TELEPHONE O24 &Ogr;5/9&Ogr;33

Note: ENBI IMUTH bv, fax &ogr;240s/9034

Kamperweg 1, NL-6361 GZ Nuth;

STEINZEUG GmbH, Max-Planck-Straße 6, D-50858 Cologne

Designation: "Pipe coupling"

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BVMJ (4227) 09 January 1996

Stoneware pipes, but also cast iron pipes and plastic pipes made of a thermosetting material, are often used as sewage or rainwater pipes. To connect individual pipe sections to form a longer pipe, the individual pipe sections have a socket with an enlarged diameter at one end, while the other end has the same diameter as the rest of the pipe body, but is usually referred to in technical terms as a so-called "pointed end". The molded socket has an inner diameter such that another pipe section can be pushed into it with its pointed end. By means of very different sealing systems, a reliable seal is achieved for the pipeline thus formed, both from the inside to the outside and from the outside to the inside, after pushing a pointed end into the socket of an associated neighboring pipe.

It is problematic with such pipes if a piece of pipe in the middle of a longer assembly, which is laid underground, for example, has a defect, which could cause the medium flowing inside the pipe to leak out. Such defects leading to leaks can arise, for example, from damage to the pipe as a result of construction work, e.g. with excavators, pickaxes or earth drills.

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Because the pipe is laid underground or by means of some kind of fastening element on a surface or a supporting structure and in particular because of the socket-shaped connection, it is not possible to replace a single defective pipe section in the overall system. For example, if a single pipe section of a stoneware pipe laid underground is destroyed during excavation work, it is not possible to install a new pipe section in its place without exposing a large part of the pipe to achieve the necessary flexibility to insert the pointed end of the replaced pipe section into the socket of the adjacent pipe section of the existing pipe. As it is therefore not possible to replace a single pipe section in such pipes, defective pipe sections are usually sealed from the outside using various types of bandages or sleeves, whereby these connection points have often subsequently proven to be weak points and places where leaks occur again.

The invention is based on the object of developing a pipe coupling, in particular for a stoneware pipe to be repaired, which enables the replacement of a single pipe section that is connected to adjacent pipe sections.

This object is achieved by a pipe coupling according to the invention, which

a sleeve-shaped central part having an inner diameter that is slightly larger than the outer diameter of the tube, the central part being provided with an external thread at two ends,

two ring-shaped sealing elements made of an elastic material, the inner diameter of which is adapted to the outer diameter of the pipe,

and two union sleeves, each with an internal thread and a contact surface arranged at right angles to the central axis of the union sleeve

wherein a sealing element can be inserted into a union sleeve, an inner diameter of the contact surfaces is slightly larger than the outer diameter of the pipe and the union sleeves with the internal threads can be screwed onto the external threads of the middle part in such a way that the sealing elements can be pressed axially against an end face of the middle part by means of the contact surfaces and are consequently radially deformable.

With the pipe coupling according to the invention, a pipeline that needs to be repaired can be sealed again in a very simple manner, for example, by first cutting open the defective pipe section and removing it completely from the assembly. Then a suitable pipe section that can be used as a replacement is divided into two parts, preferably in the middle area, as perpendicular as possible to the longitudinal axis of the pipe. The section with the pointed end is inserted into the corresponding socket of the adjacent pipe section in the assembly and the section with the socket is put onto the pipe section in the assembly, which borders with its pointed end on the removed defective pipe section. If the damage to a defective pipe section is very localized (e.g. a small hole), this pipe section can even be reused in the form of two parts after a separation process as described above.

Before using the sections, the pipe coupling according to the invention, consisting of the aforementioned individual parts, is pushed onto one of the sections. This is then pushed over the joint that occurs at a separation point between the two sections of the replacement pipe, so that this joint is in the area

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between the two sealing elements. The union sleeves are then screwed onto the middle section from both sides until the sealing elements are radially deformed as a result of the axial pressure and create an absolutely tight connection between the outer pipe surface and the middle section.

By means of the pipe coupling according to the invention, a bridge is created between the two sections of a replacement pipe section, which reliably prevents both axial displacement of these sections and radial displacement of the sections. This means that defective pipe sections from a stoneware pipe laid in a composite, for example, can be replaced reliably and with very little effort, without the need to expose large lengths of pipe to achieve the necessary mobility of the individual pipe sections.

According to one embodiment of the pipe coupling, it is proposed that the end faces of the middle part each have a radially inward-facing, circumferential inclined surface.

This inward-facing bevel causes the sealing elements to deform very reliably radially inwards as a result of the axial pressure exerted by the union sleeves, thus creating a very secure and pressure-resistant seal between the middle section and the outer pipe surface.

It is also particularly advantageous if the contact surfaces are each designed as an annular surface arranged on a collar of a union sleeve that is angled inwards at a right angle.

In this way, the contact surfaces can be manufactured very easily, and the ring-shaped design ensures a particularly even distribution of the contact pressure.

In further developing the invention, it is provided that a sliding ring is provided between the sealing elements and the respectively associated contact surface.

By choosing the right material for the sliding ring, a significant reduction in the friction torque when tightening the union sleeves can be achieved, as there is now a relative movement between the sliding ring and the union sleeve and a sliding movement with high friction between the union sleeve and the sealing element made of an elastic material is avoided.

Furthermore, according to the invention it is proposed that the union sleeves each have an annular groove between the internal thread and the contact surface, into which a collar provided on the sealing elements extends.

This allows the sealing elements to be held particularly securely in the union sleeves, and when the union sleeves are tightened, unwanted displacement of the sealing elements, which could result in incomplete sealing, is reliably prevented.

Finally, it is particularly advantageous to provide cams distributed around the circumference of the central part and/or the coupling sleeves.

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These male-shaped cams, which protrude outwards, are expediently arranged in such a way over the circumference of the central part and/or the coupling sleeves that a specially adapted key with female-shaped recesses can be placed on them in order to achieve the tightening torque required for pressing the sealing elements between the central part and the coupling sleeves without
to be able to deal with difficulties.

The invention is explained in more detail below using an embodiment shown in the drawing. It shows;

Fig. 1 is an exploded view of a pipe coupling in section;

Fig. 2 the pipe coupling in assembled condition in partial section and

Fig. 3 half of a side view of the pipe coupling.

As shown in Fig. 1, the pipe coupling consists of a sleeve-shaped middle part 1, two union sleeves 2, two ring-shaped sealing elements 3 and two sliding rings 4. The inner diameter 5 of the middle part 1 is slightly larger than the outer diameter of a pipe to be repaired (not shown).

The middle part 1 also has an external thread 6 at each of its two ends. Front sides 7 of the middle part 1 each have a radially inwardly directed circumferential inclined surface, which is at an angle of 45° to a central axis 8 of the middle part 1. In the area between the external threads 6, cams 9 are provided that are rectangular in cross section and are evenly distributed over the circumference of the middle part 1.

The union sleeves 2 each have an internal thread 12 at one end. At the other end, facing away from the front side 7 of the middle part 1, the union sleeves 2 are each provided with a contact surface 13 arranged at right angles to the central axis 8. These contact surfaces 13 are each designed as a circumferential ring surface arranged on a collar 14 of a union sleeve 2 that is angled inwards at right angles. An annular groove 15 is provided between the internal thread 12 and the contact surface 13, the width and depth of which is adapted to the sliding rings 4 and the collar 10 on the sealing elements 3.

The sealing elements 3 are in the form of rings, which have a right-angled, circumferential collar 10 at one end. The other end of the sealing elements 3, which faces a front side 7 of the middle part 1, is rounded on the outside and is provided with an axially aligned annular gap 11, which can be expanded by excess pressure inside the pipe so that an outside lip is pressed against the inside of the middle part 1 and an inside lip is pressed against the outside of the pipe. A medium under pressure inside the pipe can penetrate into the annular gap 11 via the opening cross-section and consequently expand the relevant end of the sealing element 3, whereby a reliable seal between two stoneware pipes can be achieved even if their center axes are not exactly aligned with one another.

The inner diameter 5 of the middle part 1 corresponds to the common inner diameter of the sealing elements 3 and the sliding rings 4 as well as the diameter 16 of the union sleeves 2 in the area of the collars 14.

Fig. 2 shows the pipe coupling according to the invention in the assembled state of the individual components. The sliding rings 4 and the sealing elements 3 are each inserted into the annular grooves 15 of the union sleeves 2, with the sliding rings 4 being arranged between the sealing elements 3 and the collars 14 of the union sleeves 2.

are. The union sleeves 2 are each screwed onto the external threads 6 of the middle part 1 with their internal threads 12. However, the screwing is initially only carried out up to a point at which no significant pressure is exerted by the contact surface 13 of the collar 14 of a union sleeve 2 on the sliding ring 4 or the sealing element 3. The internal diameter of the sealing elements 3 therefore initially remains unchanged compared to the initial state.

If a leak in a stoneware pipe is to be repaired by using the pipe coupling according to the invention, it is first necessary to completely remove the defective pipe section from the assembly. Of the adjacent pipe sections, which may still be in the ground, one has a socket at its end, while the other has its so-called pointed end pointing towards the gap in the pipe. A pipe section intended for replacement that is the same as the defective pipe section or that only has a small defect itself may have to be cut into two parts at the defective point using a cutting device, preferably perpendicular to its longitudinal axis, whereby one of the two sections should be shortened by an amount in the order of magnitude of the axial socket length to make it easier to assemble. The pipe coupling pre-assembled as described above is then pushed onto one of the two sections, whereupon both sections are inserted or plugged into the corresponding ends of the pipeline on both sides of the gap. The two sections are aligned with the longitudinal axis of the pipeline and the pipe coupling according to the invention is then pushed over the separation point between the two sections. The previously mentioned shortening of one of the sections to make it easier to assemble must in any case be carried out in such a way that the gap remaining between the two sections after their assembly has a smaller axial extent than the length of the middle part 1. The pre-assembled pipe coupling must therefore be in the area of the separation point between the

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both parts so that the gap is completely in the area of the middle part 1 of the pipe coupling. Then it is only necessary to tighten the union sleeves 2, whereby the sealing elements 3 are pressed axially against the end faces 7 of the middle part 1 provided with inclined surfaces by means of the contact surfaces 13. This axial pressing causes, among other things, the supporting effect of the inclined surface on

the front side 7 a radial deformation of the sealing element 3 consisting of an elastic material, whereby this in turn is pressed between the middle part 1 or the union sleeve 2 and the outside of the respective parts to be connected, not shown, and thus brings about a reliable seal.

In order to achieve the torque required for the deformation of the sealing element 3 between the union sleeve 2 and the middle part 1, cams 9 are arranged evenly distributed over the circumference of the middle part 1 in the area between the external threads 6, while cams 17 are formed on the union sleeves 2, as can be seen from Fig. 3, in the area of the angled collar 14, also distributed over the circumference. Both the recesses 9 and the cams 17 allow special keys (not shown) to be attached, which are equipped with corresponding matrix-shaped indentations. Due to the leverage effect, the torques required for secure sealing can be achieved easily by hand with the help of such special keys.

Claims (7)

- 10- Protection claims: 1. Pipe coupling, in particular for a stoneware pipe to be repaired, with: a sleeve-shaped central part (1) which has an inner diameter (5) that is slightly larger than the outer diameter of the tube, the central part (1) being provided with an external thread (6) at each of its two ends, two ring-shaped sealing elements (3) made of an elastic material, the inner diameter of which is adapted to the outer diameter of the pipe, and two union sleeves (2), each with an internal thread (12) and a contact surface (13) arranged at right angles to the central axis (8) of the union sleeve (2), wherein a sealing element (3) can be inserted into a union sleeve (2), an inner diameter (16) of the contact surfaces (13) is slightly larger than the outer diameter of the pipe and the union sleeves (2) with the internal threads (12) can be screwed onto the external threads (6) of the middle part (1) in such a way that the sealing elements (3) can be pressed axially against an end face (7) of the middle part (1) by means of the contact surfaces (13) and as a result can be radially deformed, 2. Pipe coupling according to claim 1, characterized in that the end faces (7) of the central part (1) each have a radially inwardly directed, circumferential inclined surface. · ·· ■ - 11 - 3. Pipe coupling according to claim 1 or 2, characterized in that the contact surfaces (13) are each designed as an annular surface arranged on a collar (14) of a union sleeve (2) that is bent inwards at a right angle. 4. Pipe coupling according to one of claims 1 to 3, characterized in that a sliding ring (4) is provided between the sealing elements (3) and the respectively associated contact surface (13). 5. Pipe coupling according to one of claims 1 to 4, characterized in that the union sleeves (2) each have an annular groove (15) between the internal thread (12) and the contact surface (13), into which a collar (10) provided on the sealing elements (3) extends. 6. Pipe coupling according to one of claims 1 to 5, characterized in that cams (9 and 17) are provided on the central part (1) and/or the coupling sleeves (2) distributed over the circumference. 7. Pipe coupling according to one of claims 1 to 6, characterized in that each sealing element (3) is rounded on the outside at its end facing an end face (7) of the central part (1) and is provided with an axially aligned annular gap (11).