EP0883771A1

EP0883771A1 - Pipe connection

Info

Publication number: EP0883771A1
Application number: EP97917999A
Authority: EP
Inventors: Rolf Diederichs
Original assignee: Mannesmann AG
Current assignee: Mapress GmbH and Co KG
Priority date: 1996-02-28
Filing date: 1997-02-19
Publication date: 1998-12-16
Also published as: JP2000505531A; DE19609257C2; US6059338A; CA2248301A1; CN1212750A; WO1997032153A1; DE19609257A1; PL328869A1; KR19990087281A; CZ276298A3

Abstract

The invention relates to a pipe connection in a pipe whose smooth-ended end section is pushed onto a metal fitting which has at least one sheath-like region extending lengthways and provided with a stop element located at the start of the sheath region and projecting radially outwards; a seal is provided between the pipe and fitting, which are joined permanently with the aid of a press tool which is applied on the outside and deforms the pipe plastically. To make a pipe connection of this type suitable for high pressures and temperatures and usable in different application fields it is proposed that the pipe (4, 4') and fitting (1) should be made in the known way of plastically deformable metal and a seal (5, 5') should be provided in the contact region between the outer surface of the fitting (1) and the inner surface of the pipe (4, 4') fitted onto it, said seal covering the entire contact region; the contact region should be provided with at least one crimp-type deformation point (7') which forms the axial securing element at the fitting end and also grips the fitting (1); the distance between the deformation point (7) and the end face of the fitting (1) is small enough to ensure that the seal (5') in that region is also gripped by the deformation.

Description

description

Pipe connection

The invention relates to a pipe connection according to the preamble of the main claim.

A generic pipe connection is known from Geberit (see

Extract from the company brochure). In this system, a so-called composite pipe is pushed onto a gunmetal fitting, the composite pipe consisting of an inner pipe that transports the liquid with an aluminum jacket and an overlying casing pipe that takes over the external protection. Inner tube and cladding tube are made of plastic. The fitting has a region extending in the longitudinal direction, which is provided with a stop, up to which the pipe to be connected is pushed on. The area adjacent to the stop has two inner grooves, in each of which a sealing ring is arranged. The rest of the section is heavily contoured so that the tube that is slid on can be molded into the contour during pressing. After being pushed on, a pair of crimping pliers is attached and the pipe is pressed on both in the sealing ring area and in the contoured area. The sealing ring area takes on the sealing function and the contoured area the axial securing. A disadvantage of this system is that the composite pipe can only be used for a narrow temperature and pressure range. Furthermore, the fitting is very complex to produce, since the contoured end regions and the sealing ring region have to be manufactured precisely.

Another press connection system is known from Deutsche ALWA GmbH (see excerpt from the company brochure). With this system for copper pipes and fittings made of copper there is a continuous inside in the almost flush-fitting fitting

Rubber cuff arranged. In the middle, the cuff has a radially inwardly extending web, which serves as a stop for the inserted tubes. In order to axially fix the inserted rubber sleeve, the end areas of the fitting are flanged inwards. With a wide pressing jaw having pressing pliers, two spaced apart from the fitting Beads are formed in such a way that the inserted tube is pressed in in this area. The disadvantage of this system is that the press jaw takes up a lot of space, so that pressing in narrow areas becomes impossible. In addition, an extension is required for the majority of the fittings, especially for T-pieces, so that the pressing tongs can be attached.

DE 91 13 050 U1 is a connection for line pipes can be removed, consisting of a fitting having a socket on which a protective sleeve covering the socket is detachably arranged at a radial distance from the socket and a composite pipe, the end region of which with radial plastic deformation with the one sealing ring having connecting piece is connectable. In order to connect the end of the composite pipe to the connecting piece, the protective sleeve is separated from the fitting and pushed back onto the pipe to such an extent that the end of the composite pipe can be radially pressed with a pressing pliers under deformation. After pressing and removing the crimping pliers, the protective sleeve is connected to the fitting as originally, so that the deformed area of the composite pipe is not visible from the outside, the pushed-on protective sleeve also forming a kink protection. This line connection is very expensive to manufacture, since the socket of the fitting must be specially designed in order to secure and seal the composite pipe pressed thereon sufficiently. In addition, the sealing point is so far removed from the end face of the socket of the fitting that a gap formation between the outer surface of the socket and the inner surface of the lifted composite pipe is not excluded.

A differently designed conduit connection is disclosed in DE-GM 74 06 802. This consists of a coupling ring made of thermoplastic plastic for connecting butt-jointed tube ends with outside reinforcements such as ribs, beads or the like. The

Coupling ring has a circumferential bead which engages in the gap of the butt abutting pipe ends and ring surfaces which conically decrease in the outer diameter towards the coupling ring ends. The coupling ring can be inserted into the pipe ends and can be firmly attached by gluing, preferably using a two-component adhesive. This pipe connection has the Disadvantage that the pipes to be connected must be provided with external reinforcements to ensure the required rigidity of the connection. In addition, the coupling ring must be provided with conical ring surfaces in order to ensure perfect bonding.

The object of the invention is to provide a pipe connection of the generic type, which consists of simple to produce elements, which is suitable for higher pressures and temperatures and in which the risk of gap formation is excluded.

This object is achieved with the features specified in the characterizing part of claims 1 and 4. Advantageous further developments are part of subclaims.

An advantage of the pipe connection according to the invention is that the required positioning of the pushed-on pipe on the fitting can be recognized directly visually without any additional aids. The metallic press connection, which has been tried and tested for years by deforming the pipe and fitting, is retained, so that high axial

Longitudinal forces and thus high internal pressures can be transmitted. In special cases with extremely high demands on the axial safety, it may be necessary to provide two or more bead-like indentations spaced apart from one another. It is essential to the invention that the distance from the deformation point to the end face of the fitting is so small that the

Area lying seal is also detected by the deformation. In this way, the formation of a gap between the outer surface of the fitting and the inner surface of the pushed-on pipe is prevented.

Advantageously, the stop is designed as a roof-like or flange-like bead to z. B. with presses or lathes in a simple manner. The seal is preferably made of elastomer, e.g. B. butyl rubber, EPDM, fluororubber, etc. manufactured. Depending on the intended use, other sealing materials can also be used, especially with regard to higher temperatures and aggressive media to be transported. To the To keep the cross-sectional change in the connection area as small as possible, a range of 0.5 to 10 mm is selected for the thickness of the seal, depending on the pipe diameter. The end region of the fitting, including the stop, can be pressed from a pipe section or can be made from solid material by turning or extrusion. This basic element can be connected to an elbow, T-piece or threaded part by welding. As a special case, the stop can even be omitted if the element to be connected z. B. threaded part itself has a stop.

Another possibility of achieving the object is characterized in that a hardening adhesive is applied in the contact area between the outer surface of the fitting and the inner surface of the pushed-on pipe. This creates a cohesive connection that both the

Sealing function as well as securing against axial displacement takes over. A special adhesive, e.g. used a two-component adhesive based on epoxy resin. The advantage of this connection technology can be seen in the fact that no press tool is required at low line pressures. In this case, the wall thicknesses for pipe and fitting can be selected to be very small, since they are not designed with regard to the pressing, but only have to withstand the internal pressure. The thin wall of the fitting also has the advantage that the inner diameter of the line is only slightly reduced. If higher line pressures are required, this pipe connection can also be mechanically pressed for gluing.

Compared to the glued pipe connections in fittings and pipes made of plastic, the proposed system has the advantage that the area of application is considerably larger with regard to temperature and internal pressure.

When laying pipes, depending on the area of application, e.g. B. constantly moist room may be required to protect the outer surface. A plastic coating of the pipes known per se has proven to be particularly advantageous. This also applies to the outer area of the fitting stop. The pipe connection according to the invention is explained in more detail in the drawing with the aid of a few exemplary embodiments.

Show it:

1 shows a longitudinal section through a first embodiment of the pipe connection according to the invention FIG. 2 as FIG. 1, but a variant of the first embodiment

Figure 3 as Fig. 1, but a further embodiment

In Figure 1, a first embodiment of the pipe connection according to the invention is shown in a longitudinal section, wherein the state before and in the right half the state after the pressing can be seen in the left half of the figure. The core of the connection is a fitting 1 made of plastically deformable metal, which has a stop 2 extending radially outwards. This is followed at least on one side by a longitudinally extending cylindrical section 3, 3 '. In this exemplary embodiment, two smooth-ended conduit pipes 4, 4 'made of plastically deformable metal are pushed onto the fitting 1, namely up to the stop 2. In the contact area between the fitting 1 and the conduit pipe 4, 4', between the outer surface of the cylindrical section 3, 3 'of the fitting 1 and the inner surface of the pushed-on tube 4,4', a seal 5,5 'is arranged. This seal 5.5 'extends over the entire contact area. To facilitate the pushing on, the outer surface of the seal can be 5.5 'with a

Liquid wetted or lubricated with a soap-like agent. The seal 5,5 'takes over the seal in this embodiment, so that the liquid to be transported can not penetrate outside. So that this connection can also transmit the axial forces caused by the internal pressure, if necessary and depending on the line pressure, two bead-like pressing points 6 ", 7" are formed in succession by a pressing tool, not shown here, of which a bead-like pressing point 7 'is located at the end of the cylindrical section 3,3 '. The pressing points 6 ', 7' are characterized in that both the fitting 1 and the respective pushed-on pipe 4, 4 'are also deformed. The kind of Contact z. B. hexagonal or lemon-shaped segments depends on the contour of the mouth of the press jaws, not shown here.

Figure 2 shows in the same longitudinal section a variant of the embodiment described above, wherein the same reference numerals have been used for the same parts. For pipe connections where e.g. If an unalloyed steel is used for the fitting 1 and the line pipes 4, 4 ', it may be necessary, depending on the area of application, to protect the outer surface from a corrosion attack. For this purpose, the respective conduit 4, 4 'is covered with a plastic jacket 9, 9' in a manner known per se. Likewise, the exterior outside of the cylindrical section 3, 3 'of the fitting 1 is covered with plastic 8 or coated with plastic paint. When pushing on the conduit 4, 4 ', care must be taken that the respective end face of the conduit, 4, 4' extends up to the casing 8 of the stop 2.

When the two bead-like pressing points 7, 7 'are pressed on, the plastic jacket 9, 9' is also deformed. This procedure has the advantage that reworking after pressing is not necessary or only to a small extent.

Figure 3 has in the same longitudinal section as Figure 1, a further embodiment of the pipe connection according to the invention, wherein the same reference numerals have been used for the same parts. In contrast to Figure 1, in the contact area between the outer surface of the fitting 1 and the inner surface of the respectively pushed pipe 4, 4 ', not a seal, but e.g. a curable adhesive 10, 10 'is arranged. After curing, this results in a material connection, the adhesive 10, 10 'taking on both the sealing function and the axial securing. Since the forces to be transmitted by such a connection are limited, a bead-like pressing can additionally be formed, as in FIG. 1. The adhesive connection will be sufficient for lower pressure levels, while the additional mechanical axial securing will be preferred for higher pressures and possibly additional vibration stresses on the lines.

Claims

Claims:

1. Pipe connection with a pipe, the smooth end portion of which is pushed onto a metallic fitting, which has at least one sleeve-like region extending in the longitudinal direction, which is provided with a stop lying at the beginning of the extension and extending radially outwards, and in the between the pipe and fitting a seal is arranged and pipe and fitting are inseparably connected to one another by means of an externally attached pressing tool which plastically deforms the pipe, characterized in that the pipe (4, 4 ') and fitting (1) are made of plastically deformable metal in a known manner and in A gasket (5,5 ') extending over the entire contact area is arranged between the outer surface of the fitting (1) and the inner surface of the pushed-on tube (4,4') and the contact area also has at least one bead-like at the fitting end which forms the axial securing means the fitting (1) telle (7 ') and the distance from the deformation point (7') to the end face of the fitting (1) is so small that the seal (5 ') lying in this area is also included in the deformation.

2. Pipe connection according to claim 1, characterized in that the seal (5,5 ') consists of an elastomer.

Pipe connection according to claim 1 and 2, characterized in that the thickness of the seal (5.5 ^* ) depending on the dimension of the pipes (4,4 ') in one

Range from 05 to 10 mm.

4. Pipe connection with a pipe, the end section of which is pushed onto a fitting which has at least one sleeve-like region which extends in the longitudinal direction and is provided with a stop which lies at the beginning of the extension and extends radially outwards and by means of a stop over the whole Contact area between the outer surface of the fitting and of the inner surface of the pushed-on pipe adhesive, a material connection is produced, characterized in that the pipe (4, 4 ') has a cylindrical smooth outer surface and a smooth end section and pipe (4, 4') and fitting (1) are made of plastically deformable metal.

5. Pipe connection according to claim 4, characterized in that the adhesive (10, 10 ') is a two-component adhesive based on epoxy resin.

6. Pipe connection according to claim 4 and 5, characterized in that at high internal pressures the contact area at least one the axial

Fuse supporting the pipe (4,4 ') and the fitting (1) with the bead-like deformation point (6', 7 ').

7. Pipe connection according to claim 1 or 4, characterized in that the tube (4,4 ') and fitting (1) are made of stainless steel (stainless steel).

8. Pipe connection according to claim 1 or 4, characterized in that the tube (4,4 ') and fitting (1) are made of titanium.

9. Pipe connection according to one of claims 1 to 8, characterized in that the fitting (1) outside the cylindrical section (3,3 ') is provided with an anti-corrosion agent (8).

10. Pipe connection according to one of claims 1 to 8, characterized in that the outer surface of the tube (4,4 ') is provided with an anti-corrosion agent. 11. Pipe connection according to claim 9 or 10, characterized in that the anti-corrosion agent is a plastic coating (10,10 ').

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