DE2542644A1 - EXPANSION SLEEVE FOR PIPES - Google Patents

Description

Ba 3370

Center Scientifique et Technique du Batiment, Paris / France

Expansion sleeve for pipes

The invention relates to an expansion sleeve for pipes, in particular for plastic pipes.

Plastic pipes have considerable coefficients of linear thermal expansion; they are for example in the case of polyvinyl chloride about six times as large and in the case of polyolefins about twelve times as large as in the case of steel pipes. The assembly of such plastic pipes requires therefore the attachment of relatively numerous expansion sleeves, with their arrangement in a certain Connection with the rigid attachment points must be made. The remaining attachment points must be free Allow sliding movement of the pipe so that the pipe does not experience any impermissible deformation.

The invention is based on the object of creating an expansion sleeve that is used when assembling such Plastic pipes meets the requirements and which also has further advantages over the known designs.

According to the invention, this object is essentially achieved in that a flexible, smooth tube is attached s is connected at one end with two rigid rings, which are connected to the ends of the tubes by connecting elements

609817/0319

binding stand, that also the flexible, smooth tube and said rigid rings are disposed inside a rigid shell on which the flexible tube rests can support, and that one of said rings is slidable relative to the rigid jacket, which in turn attached to the other ring.

Such an expansion sleeve does not require any appreciable actuation force on the part of the plastic pipe, because the expansion sleeve itself - even before each expansion of the plastic pipe - is subject to tensile stress exerts on the free end of the tube, which is due to the bias applied to the expansion sleeve will.

In addition, the pressure prevailing inside the expansion sleeve according to the invention does not act as in most known cases, an elongation of the expansion sleeve, since the effects of the pressure on both ends are exactly in balance and because the contact surfaces with the fluid are designed to be exactly symmetrical. The pressure Rather, it even causes a tendency to shorten the expansion sleeve, since the flexible tube attaches itself to the puts on rigid outer coat.

These and other features of the invention emerge from the subclaims and from the following description of an embodiment. Show in the drawing

1 shows a schematic representation of the assembly of an expansion sleeve on a pipeline;

60981 7/0319

2 shows a longitudinal section through an embodiment of the expansion sleeve according to the invention before assembly;

3 shows a longitudinal section according to FIG. 2 without assumed expansion of the plastic pipe;

4 shows a longitudinal section according to FIGS. 2 and 3, but with assumed expansion of the plastic pipe.

Fig. 1 shows the assembly of a line of a plastic pipe 1, which is slidable in support bearings 2 to 2c and is firmly held in support bearings 3 and 4.

The fixed support bearing 4 is located on an inventive Expansion sleeve 5

This expansion sleeve 5, which is located between the ends la and Ib of the plastic pipe 1, contains a flexible tube 6 (Fig. 2, 3 and 4) made of rubber or a Elastomer; the material of this flexible tube 6 must with the fluid to be transported under the Operating conditions (especially taking into account the temperature) must be compatible.

The flexible tube 6 is glued at its ends with two rigid rings 7 and 8, which for guidance and Support of the flexible tube 6 are used. These rings 7, 8 must be those generated by the fluid Can withstand temperature, also the pressure of this fluid transmitted by the flexible tube 6 will. The rings 7 and 8 are at both ends

609817/0319

-H-

edited so that on the one hand, a repulsed one Part 6a, 6b of the flexible tube 6 and at the other end reinforcement sleeves 9 and 10, which are on the outside of the flexible tube 6 are arranged. These sleeves 9 and 10 are reinforcing elements that are intended to prevent that the flexible tube 6 adapts to the shape of the rings 7 and 8 under the action of the pressure. These reinforcement sleeves 9 and 10 are constantly with the flexible tube 6 and with the rings 7, 8, preferably by gluing, tied together. In a modified embodiment, the reinforcing sleeves 9 and 10 can be made in one piece with the pipe 6, the entire element being produced, for example, in a casting or injection molding process.

The processing of the rings 7 and 8 should also be done so that there is no risk of damage to the Tube 6 and the sleeves 9, 10 consists of a sharp edge. To avoid any editing, you can do this Manufacture parts in a casting, pressing or injection process.

The rings 7 and 8 are connected to the ends la, Ic of the pipe via connecting elements 11 and 12, which are designed as clamps and have an inner annular projection 13 on which the ends la and Ib of the pipe 1 on the one hand and the rings on the other 7 or 8 come to the system. The end of the connecting element 11 or 12 which is in engagement with the pipe 1 can either enclose the pipe from the outside (as shown) or engage in the pipe. On the connecting element 11 a receptacle 15 is provided for the support bearing ¹ I, which serves as a fixed point.

6098 17/0319

2 ' ■ ·.' 6 4

A rigid jacket 16 is provided over the flexible tube 6 and the rings 7 and 8, which by the fluid generated temperature and fluid pressure (transmitted from flexible tube 6) must resist.

The ring 7 must allow a sliding movement of the jacket 16 when the flexible tube 6 is displaced; For this reason, the ring 7 has a greater length than the ring 8 to which the jacket 16 is firmly connected is.

The inner surface of the jacket 16 and the outer surface of the ring 7 must also be designed in a suitable manner in order to enable said sliding movement of the shell 16.

As Fig. 2 shows, an outer ring 17 is provided between the connecting element 11 and the jacket 16, whereby the flexible tube 6 is kept under a certain prestress before its assembly.

This outer ring 17 is mounted when the expansion sleeve is manufactured, but must be easily removed can be when the expansion sleeve is installed in the finished pipeline network, shortly before the Installation.

The expansion sleeve works as follows:

If the expansion sleeve 5 is mounted on the pipe 1 and the bearings 3 and 4 are attached to the fixed points, so the outer ring 17 can be removed. As long as there is no

609817/0319

- '/ 644

Fluid located in the pipe 1 then results a tensile stress on the free end of the pipe 1. This tensile stress is exerted by the flexible pipe 6 caused during the manufacture of the expansion sleeve 5 in the factory when assembling the outer ring 17 is placed under a bias. This tensile stress

is carried by the pipe, the expansion of which is to be ensured, to the next plague point.

If the network now comes under the pressure of the fluid at ambient temperature, nothing occurs in the pipe Expansion to. On the contrary, the tensile stress on the flexible tube 6 increases somewhat because its wall under the effect of the mean fluid pressure in contact with the inner wall of the rigid jacket 16 comes, as Fig. 3 illustrates.

If the temperature and the pressure of the fluid increase in the network, then occurs in the plastic pipe 1 an extension to; it is taken up in that the flexible tube 6 returns to its starting position, which causes the shell 16 to slide on the ring 7.

The expansion sleeve 5 is not noticeably stressed by the plastic pipe 1; the effect of the .Possibly. The pressure prevailing inside the network does not cause any stress in the expansion sleeve, which an expansion of the pipe 1 would be opposed.

6098 17/0319

Such an expansion sleeve according to the invention can be used before geous in central heating systems, also in hot water distribution circuits and in all other pipeline systems in which temperature changes of the fluid can occur.

60981 7/0319

ORIGINAL INSPECTED

Claims (8)

Claims /l.y/ Expansion sleeve for pipes, especially for plastic pipes, characterized in that a flexible, smooth tube is connected at its ends to two rigid rings which are connected to the ends the tubes are connected via connecting elements, that also the flexible, smooth tube and said rigid rings are arranged inside a rigid jacket on which the flexible Can support tube, and that one of said rings is slidable relative to the rigid Coat, which in turn is attached to the other ring. 2. expansion sleeve according to claim 1, characterized in that the flexible tube inside said rings is attached and that its ends are turned back around the ends of the rings. 3. expansion sleeve according to claims 1 and 2, characterized in that on the outside of the flexible Tube and reinforcing sleeves made of flexible material are provided on the rigid rings. 4. expansion sleeve according to claim 3, characterized in that that the flexible tube and the reinforcing sleeves are made in one piece in an injection molding, casting or pressing process are made. 609817/0319 2 b -i 2 6 A 5. expansion sleeve according to claim 1, characterized in that that the connecting elements are designed as sleeves, which at the same time with the pipe and with the rigid ring in engagement, each of these two sleeves having an inner annular projection, on which the ends of the pipe and the adjacent rigid ring come to rest, the sleeve can come to rest on one of the ends of the rigid jacket. 6. expansion sleeve according to one of claims 1 to 5, characterized in that the flexible tube in front the assembly of the expansion sleeve in the pipeline network is subjected to a pretensioning. 7. expansion sleeve according to claim 6, characterized in that the bias is generated with the aid of an outer ring which is releasably arranged on one of the rigid inner rings between one of the connecting elements and the rigid outer coat. 8. expansion sleeve according to claim 5, characterized in that that one of the bearings for fixing the pipe network is attached to one of the connecting elements. 609817/0319