DE9419865U1 - Transition pipe connection - Google Patents

Description

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Dipl.-Ing. Harald Ostriga* J. ...;." · j .' · "I H- ^{Telex 8591274os} P ^ad Dipl.-ing. Bernd Sonnet*

Dipl.-ing. Jochen-Peter Wirths h~^,

^{r D} Stresemannstr. 6-8

* Authorized by the European Patent Office 42275 Wuppertal-Barmen

Oslriga, Sonnet & Wirlhs ■ PO Box 20 16 53 ■ D-42216 Wuppertal

S/g

Applicant: Reinert. Ritz GmbH

Ernst-Heinkel-Str. 2
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48531 Nordhorn

Designation

of the invention: transition pipe connection

The invention relates to a transition pipe connection with at least one plastic pipe with a sleeve-like widened pipe end, with a metal pipe section that can be inserted into the pipe end and with a sleeve that can be pushed over the respective pipe end, the pipe section having on its outside several circumferentially extending grooves with a preferably trapezoidal cross-section and the sleeve being able to be pressed over the sleeve-like widened pipe end with the pipe section firmly seated therein, the inner diameter of the sleeve being larger than the outer diameter of the pipe section following the pipe end, but smaller than that of the sleeve-like widened pipe end.

In a known transition pipe connection, e.g. according to DE 88 15 273 U1, a positive-locking clamp or squeeze connection is created, whereby the sleeve presses displaced material from the sleeve-like widened end of the plastic pipe partially into the circumferential grooves of the metal pipe body.

Postgiroami Crcdil- and Volksbank eGinbll Commerzbank &Lgr;&Ogr; USl-IdNr,

Essen ·Wuppertnl-Bariiiicn· · · · · Wunpcrlal-ßamicn VAT-No.

(BLZ3Ö0 100 43)445 04-431 * (BCzJiSWOO 38) 5awS<«TÄ4 &iacgr; ** · (oT.Z.330 400 01) 4 034 R23 DE 12106867ft

Reinert. Ritz GmbH

A similar transition pipe connection is also known from DE 29 11 708 C2, where the deformed material of the pipe end is completely accommodated in the grooves.

In transition pipe connections of the type underlying the invention, it is important that a high tensile strength is achieved between the two pipe sections and that the plastic material in the connection area is arranged in such a way that the material is not overstressed when the connection is made, which could lead to a weakening of the subsequent pipe connection.

This is usually not always guaranteed with the known transition pipe connections, because although the displaced plastic material can be completely deformed into the circumferential grooves, it can also relax here.

One aim of the invention is to provide a transition pipe connection that can withstand higher loads while subjecting the plastic pipe section to less material stress.

A transition pipe connection that solves this problem is characterized according to the invention by a deformation ring (22) that leads the sleeve (13), has a considerably greater wall thickness than the sleeve (13) and is provided with a leading conical shoulder (26) formed on its inner circumference, which extends from a first diameter (27) on the ring face (28), which is larger than the outer diameter (24) of the adjacent free pipe section (25), to a second diameter (23)

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tapered, which corresponds approximately to the inner diameter of the sleeve (13).

According to the invention, the main focus is not on ensuring that the plastic material displaced during the crimp assembly is completely absorbed by the circumferential grooves, but rather that these are completely filled by the displaced material. The invention is based on the idea that this cannot be achieved by moving a sleeve that also forms the displacement body according to the prior art, because this sleeve tends to drive the material that is bulging outwards in front of its front edge instead of inserting it specifically into the circumferential grooves. This is only possible by using a special deformation ring according to the invention, the purpose of which is to press the material displaced by it into the circumferential grooves one after the other and, above all, while maintaining its elastic state. The sleeve, which is only pushed over afterwards, essentially aims to prevent the material molded into the circumferential grooves from returning, but does not take over the actual squeezing process.

It can be achieved that, if material protrudes outwards at all during this type of deformation, it will at least find sufficient space in the free space created by the conical shoulder that it will no longer be pushed forward significantly in front of the deformation ring.

This ensures that the displaced plastic material within the connection zone is not overstressed, but remains in an elastic state.

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state that would theoretically allow the pipe section in question to elastically deform again after the sleeve has been removed. A piece of plastic pipe treated in this way is not stressed, in contrast to the known transition pipe connections of the same type.

The slope of the conical shoulder of the deformation ring and the depth of the circumferential grooves are advantageously dimensioned so that the pressed material of the sleeve-like widened pipe end completely fills the circumferential grooves of the metallic pipe piece one after the other while still in a shape-elastic state, whereby the slope of the conical shoulder of the deformation ring is preferably less than that of the step at the transition to the sleeve-like widened pipe end, whereby optimal results can be achieved.

If, according to a further embodiment, the deformation ring has a recess on its rear side for receiving a front section of the sleeve, the deformation ring and sleeve can be easily moved in the longitudinal direction of the pipe connection in one operation until the sleeve has reached its intended place for securing the connection arrangement and the deformation ring can be pulled off the metal pipe section by moving it further in the previous direction.

In order to ensure in a simple manner under all operating conditions that the circumferential grooves can be completely filled by the displaced material without any problems, it is intended that the ribs defining the circumferential grooves of the metallic pipe section are provided with essentially axially displaced

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running relief grooves to allow air displaced from the circumferential grooves to escape.

While conventional transition devices of the type outlined in the preamble of claim 2 are also intended to guarantee the tightness of the pipe connection, which sometimes - particularly due to the resilience of the material - has not been achieved with sufficient reliability, a further embodiment of the invention provides that the section of the metal pipe section having the circumferential grooves and ribs (connecting section) is preceded by a spigot end with a seal receptacle (sealing section) and the end of the plastic pipe section is widened in two stages like a sleeve, with the outermost stage being assigned to the connecting section and the inner stage to the sealing section. This spatially separates the zone of the compression connection from the seal. They are arranged axially in front of or behind one another, so that they cannot influence or hinder one another in a disadvantageous way.

There have already been crimp connections of the type described in which additional seals have been used, but these are very badly affected during the manufacture of the crimp connection and for this reason alone can only guarantee their sealing effect by chance.

The outside diameter of the sealing section of the metal pipe section should be no larger than the groove base diameter of the connecting section, but preferably smaller. This creates a frontmost rib on the metal pipe section that is limited by the circumferential groove and which

Reinert. Ritz GmbH

According to a further embodiment, it is also designed as a stop shoulder against the inner socket base of the expanded end section of the plastic pipe.

Furthermore, the invention is best understood from the following detailed description of an embodiment shown in the drawings. In the drawings, each half in longitudinal section, half in elevation:
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Fig. 1 the essential parts for a transition pipe connection according to the invention in a not yet assembled state,

Fig. 2 a 'snapshot' during the production of the transition pipe connection

Fig. 3 the finished transition pipe connection and
Fig. 3a a detail of a variant.

Components of a transition pipe connection, designated overall with 10, are a plastic pipe section 11 and a metallic pipe section 12 as well as a sleeve 13.

The plastic pipe 10, which consists of PE, PP or a similar plastic, which can be extruded, injection-molded or machined, has at least one sleeve-like widened section 14 at its free end, which is referred to below as sleeve-like widened pipe end. The entire inner axial length of this sleeve-like widened pipe end 14 is 15

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(The inner diameter is 16 and the outer diameter is 17.

A pipe section 18 of the metal pipe piece 12 corresponds to the sleeve-like widened pipe end 14, the axial length of which, which extends into the sleeve-like widened pipe end 14, is correspondingly designated by 15. This section 18 comprises several, in the embodiment four, ribs 19, 19' with circumferential grooves 20, 20' arranged between them and outside the last rib 19. The ribs 19, 19' have an outer diameter 21 which is slightly larger than the inner diameter 16 of the sleeve-like widened pipe end 14, so that a tight fit is achieved in the inserted state.

The shoulder 19" of the rib 19' located furthest at the end of the pipe section 12 strikes the internal stop shoulder 14" inclined in the same direction at the end of the sleeve-like expansion 14.

A special deformation ring 22 is used to produce a crimp connection between the pipe sections 11 and 12 pushed into one another. The deformation ring has a significantly greater wall thickness than the sleeve 13, but the same or approximately the same inner diameter 23. This inner diameter 23 is at least slightly larger than the outer diameter 24 of the "free" pipe section 25 following the sleeve-like widened pipe end 14. On the other hand, the inner diameter 23 is not inconsiderably smaller than the outer diameter 17 of the sleeve-like widened pipe end 14.

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The special feature of the deformation ring 22 is the conical shoulder 26 attached to its inner surface, which extends from a first diameter 27 on the front ring face 28, which is larger than the outer diameter 17 of the sleeve-like widened pipe end 14, to a diameter that corresponds to the inner diameter 23 of the sleeve 13. This results in a certain conical inclination, which is designated 29 and is approximately 15° in the exemplary embodiment. In contrast, the inclination 30 of the transition section 31 between the sleeve-like widened pipe end 14 and the adjacent pipe section 25 is somewhat larger and is approximately 20° in the exemplary embodiment.

This geometry, in particular the diameter ratios, are optimized in relation to the depth 32 of the circumferential grooves 20 so that the material of the sleeve-like widened pipe end 14 displaced by pushing forward the deformation ring 22 can completely fill the circumferential grooves 20 (and at least partially fill the open end groove 20'). In practice, the groove depth 32 is approximately 1 to 3 mm, depending on the nominal size of the transition connection. The air displaced by pressing the displaced plastic material into the circumferential grooves 20 can escape through longitudinal grooves 40, of which each rib 19 or 19' has one and these individual grooves 40 are arranged in a common alignment.

Fig. 2, which differs from Fig. 1 in that the two pipe sections 11 and 12 are now pushed into one another and that the deformation ring 22 has performed part of its deformation work, clearly shows how the deformation ring under diameter

Reinert. Ritz GmbH *: ·**!

tapering of the sleeve-like widened pipe end 14 presses material into the circumferential grooves 20 and finally into 20' one after the other. Due to the described arrangement and also the relatively small groove depth, this takes place in a material deformation area that is still elastic. If the finished pipe connection (Fig. 3) were not secured by the sleeve 13, the plastic material could elastically deform back to almost its original position. Consequently, the sleeve 13, unlike in the prior art, essentially has the task of preventing this elastic recovery and thereby securing the compression connection.

The deformation ring 22 is pushed completely over the sleeve-like widened pipe end 14 and then expediently over the metal pipe section until it can be removed from it. This handling makes it possible to move both the deformation ring 22 and the sleeve 13 in one operation, for which purpose a positive coupling is also provided between these rings, which is designated 33 in Fig. 2 and consists of a small rear internal recess in the deformation ring 22, into which the front sleeve end can be accommodated.

It is of course also possible to pull the deformation ring 22 back again after the squeezing work has been carried out and to remove it from the plastic pipe section 11 and only then to slide on the sleeve 13.

From Fig. 2 it is also clear that the jacket of the socket-like widened pipe end 14 is only reduced to a diameter 34, which is still slightly larger than the diameter 2 4 of the adjacent undeformed

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plastic pipe section 25 so that it is kept away from any stresses and strains.

Fig. 2 also clearly shows that the deformation shoulder 26 creates a free space in which any plastic material that protrudes outwards during the deformation process can find space and is not pushed forward in front of the front face 28 of the ring body 22.

The detail marked in Fig. 3 and shown in Fig. 3a, in contrast to the other representations, only shows a metal pipe 12' covered or coated with a thin plastic layer 35 and is intended to explain that this plastic layer 35 is also squeezed when the transition pipe connection is made, without causing any interference.

Although the transition pipe connection 10 produced in the manner described has, on the one hand, a high tensile strength and, on the other hand, also a high sealing effect, the tightness of the connection can be further increased by the measures described below.

According to the embodiment shown, the metal pipe section 12 does not end with the connecting section 18; rather, it has a sealing section 36 of length 37. This sealing section 36, which marks the tip end of the metal pipe section 12, supports sealing rings (O-rings) 39 in two recesses 38.

To accommodate the sealing section 36 of the metallic pipe section 12, the pipe section 25 of the plastic

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material pipe 11 is available, which in the embodiment represents the first stage of a two-stage socket-like expansion, the last of which is the socket-like expanded pipe end 14.

As Fig. 2 and Fig. 3 clearly show, the functions of 'connecting' and 'sealing' of the transition pipe connection are spatially and functionally separated from one another. In particular, it should be noted that the sealing zone is not involved in the creation of the connection zone in any way, and therefore cannot be damaged. It should also be emphasized that, with regard to pressure-bearing lines, the sealing zone is arranged on the pressure side in front of the connection zone, so that this connection zone cannot be affected by aggressive fluids because it is shielded by the seals 39.

Claims (8)

Expectations 1. Transition pipe connection with at least one plastic pipe with a sleeve-like widened pipe end, with a metal pipe section that can be inserted into the pipe end and with a sleeve that can be pushed over the respective pipe end, the pipe section having on its outside a plurality of grooves running in the circumferential direction with a preferably trapezoidal cross-section and the sleeve being able to be pressed over the sleeve-like widened pipe end with the pipe section firmly seated therein, the inner diameter of the sleeve being larger than the outer diameter of the pipe section following the pipe end, but smaller than that of the sleeve-like widened pipe end, characterized by a deformation ring (22) leading the sleeve (13), which has a considerably greater wall thickness than the sleeve (13) and is provided with a leading conical shoulder (26) formed on its inner circumference, which extends from a first diameter (27) on the annular face (28), which is larger than the outer diameter (24) of the adjacent free pipe section (25), to a second diameter (23) which approximately corresponds to the inner diameter of the sleeve (13). 2. Transition pipe connection according to claim 1, characterized in that the slope (angle 29) of the conical shoulder (26) of the deformation ring (22) and the depth (32) of the circumferential grooves (20) are dimensioned such that the pressed material of the sleeve-like expanded pipe end (14) completely fills the circumferential grooves of the metallic pipe section (12) one after the other while still in a shape-elastic state. Reinert. Ritz GmbH 3. Transition pipe connection according to claim 1 or 2, characterized in that the slope (angle 29) of the conical shoulder (26) of the deformation ring (22) is less than the slope (angle 30) of the step (31) at the transition to the sleeve-like widened pipe end (14). 4. Transition pipe connection according to one of claims 1 to 3, characterized in that the deformation ring (22) has a recess on its rear side for receiving a front section of the sleeve (13) (coupling region (33)). 5. Transition pipe connection according to one of claims 1 to 4, characterized in that the circumferential grooves (20) of the metallic pipe section (12) defining ribs (19, 19') are provided with substantially axially extending relief grooves (40) for the escape of air displaced from the circumferential grooves (20). 6. Transition pipe connection according to one of claims 1 to 5, characterized in that the section of the metal pipe section having the circumferential grooves and ribs (19, 19') (connecting section) is preceded by a spigot end with receptacles for sealing rings (39) (sealing section) and the end of the plastic pipe section (14) is widened in two stages like a sleeve, the outermost stage (14) being assigned to the connecting section and the inner stage (25) to the sealing section. 7. Transition pipe connection according to one of claims 2 to 6, characterized in that the outer diameter (41) of the sealing section of the metallic pipe piece Reinert. Ritz GmbH *! · · ·· ·*" (12) is at most as large as the groove base diameter (42) of the connecting section. 8. Transition pipe connection according to one of claims 1 to 7, characterized in that the foremost circumferential groove-defining rib (19') on the metallic pipe piece (12) simultaneously forms a stop shoulder (19") against the inner socket base (14") of the widened end section (14) of the plastic pipe (11).
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