DE9203999U1 - Device for flexible connection of a thermoplastic pipe - Google Patents

Description

Managing Directors: E. Barrie Stephens C. Eng. Martyn Robert Champ ("jtLJ I ^CHE Wolfgang Schön, Dipl.-Betriebswirt

^p jw ^ j^ μg; ^i ^ji M^W Klaus Straszewski, Dipl.-Ingenieur

■ Kü^^^^UEB Il I District Court Bielefeld HRB 7168

Deutsche Tecalemit GmbH Postf. 12 01 28 4800 Bielefeld 12 · K.-Oldewurtel-Str. 40 ■ Telephone (05 21) 40 49-0 · Fax (05 21) 40 49 305

Your reference Your letter in front Our reference Date

Sch/kh 19.03.92

074/337

Facility for flexible connection

a thermoplastic pipe &PSgr;

The invention relates to a plastic pipeline which consists of a thermoplastic material and has flexible elements made of an elastomer, which form a material bond with the thermoplastic component.

Plastic pipelines, as used in the automotive industry, often consist of thermoplastic pipes combined with elastomer hoses. The purpose of these elastomer hoses is to enable manual assembly onto a nozzle of a unit, such as a tank. Otherwise, such lines have all the known advantages of thermoplastic pipes. In the case of fuel lines, where the thermoplastics polyamide 11 and polyamide 12 are mostly used, the selection criteria are the excellent resistance to fuels, as well as the good permeability properties and excellent impact strength.

Sheet 2 ^Date 19.03.92

074/337

The connection between the thermoplastic pipe and the elastomer hose is currently made by pressing a double collar sleeve or similar into the thermoplastic pipe, resulting in a contour being formed on the outside wall of the pipe and then pushing the elastomer hose over the thermoplastic pipe. This connection is secured by the additional application of a hose clamp. In addition to the assembly effort, this connection technology also brings with it a potential leak point. Assembly errors, such as an insufficient length of push-on, can lead to

of the elastomer hose onto the thermoplastic pipe *

or an incorrectly fitted hose clamp can cause a leak or even completely loosen the connection. It was also found that even with a correctly fitted line, a relatively high leak rate occurs compared to other connection technologies, such as screw connections and connections with "Christmas tree ¹ ! profiles". The reasons for this lie in the high manufacturing tolerances of the elastomer hoses and in the fact that the hose clamps do not tighten completely round, but always have an oval shape, so that "leakage channels" form.

Based on this known state of the art, the invention is based on the object of designing a plastic pipeline in such a way that a completely tight and secure connection is established between the thermoplastic pipe and the flexible elastomer element.

Sheet 3 Date 19.03.92

074/337

This is achieved by using a so-called hard-soft connection technology. The previously manufactured thermoplastic pipe is placed in an elastomer processing machine and the elastomer part is injected onto the thermoplastic pipe. The complete part is then subjected to a vulcanization process. This creates a material-locking and therefore tight and inseparable connection between the thermoplastic pipe and the flexible elastomer part. To date, such a technology for combining a thermoplastic and elastomer part does not exist.

Another embodiment of the invention consists in placing the thermoplastic pipe and an elastomer hose, which has also been manufactured beforehand, over-molded with elastomer in the overlapping area and then vulcanized. This method is used when elastomer hoses that cannot be manufactured using the injection molding process or when flexible elastomer pipe segments are inserted between two thermoplastic pipe sections. The figures show in detail:

Figure 1: The direct connection of a thermoplastic plastic pipe with an elastomer hose

Figure 2: The indirect bonding of a thermoplastic pipe via a bonding layer with an elastomeric hose.

Sheet 4 Date 19.03.92

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Figure 3: The indirect connection of two thermoplastic pipes via two respective connecting layers with an elastomer hose

In Figure 1, the thermoplastic plastic pipe (1), e.g. made of polyamide 11 or polyamide 12, is pushed into an elastomer hose (2); the elastomer hose is made of a very specific material quality, e.g. X-NBR. The pipe (1) and the hose (2) overlap in the bonding area (3). Due to the selected material combination, it is possible to create a material bond between the two elements using a vulcanization process, which ensures absolute tightness for all operating conditions. The flexible connection in the direction of the arrow (5) is made using the elastomer hose (2) to the nozzle of a metal pipe socket, housing, flange or similar (not shown). The bonding area (3) of the overlap between the pipe (1) and the hose (2) has the length 1 and the diameter d.

In Figure 2, a thermoplastic plastic pipe (1) of a certain material quality is pushed into an expanded elastomer hose (2) of a certain material quality in the push-on area (8). In the outer connection zone of both, a connection is made via an elastomer molded part (4) of the corresponding material quality, which, in the process of vulcanization, ensures a material-tight bond between the pipe (1) and the hose (2) for all operating states of this connection in the overlapping areas (7.1 and 7.2).

Biatt ₅ Date ig .0.3.

074/337

The flexible connection in the direction of the arrow (5) is made using the elastomer hose (2) to the nozzle of a metal pipe socket, housing, flange or similar (not shown). The overlapping areas (7.1 and 7.2) of the pipe (1) and hose (2) and the attachment areas (8) each have the length 1 and the diameter d.

In Figure 3, two thermoplastic plastic pipes (1) and (6) of a certain material quality are pushed into an expanded elastomer hose (2) of a certain material quality in the push-on area (8). In the outer connection zones, a connection is made using two elastomer molded parts (4) of a corresponding material quality in the overlapping areas (7.1 and 7.2), which, in the vulcanization process, represents a material-tight bond between the pipes (1) and (6) and the hose (2) for all operating conditions of this connection.

Claims (9)

Protection claims 1) Pipe made of a thermoplastic material with a flexible connecting element for connection to a pipe socket, a housing, a flange, a grommet or similar, characterized in that the thermoplastic plastic pipe (1) and the elastomer hose (2) in the composite area (3) or via an elastomer molded part (4) in the overlapping areas (7.1 and 7.2) have a material-locking connection, produced by the vulcanization process. 2) Pipeline according to claim 1)
characterized in that the elastomer hose (2) is attached directly to the thermoplastic pipe (1). 3) Pipeline according to one or more of the claims D - 2) characterized in that the connection of the pipe (1) and the hose (2) with a molded part (4) is produced in a material-locking connection using the vulcanization process. 4) Pipeline according to one or more of the claims D - 3) characterized in that a material connection exists between the outer wall of the thermoplastic pipe (1) and the inner wall of the connecting element made of elastomer hose (2). Sheet g Date !9.Q _3-9 074/337 5) Pipeline according to one or more of claims 1) - 4) characterized in that one of the end faces of the thermoplastic plastic pipe (1) and the elastomer hose (2) are firmly connected to one another via a molded part (4). 6) Pipeline according to one or more of the claims D - 5) characterized in that the thermoplastic plastic pipe (1) and/or (6) is made of polyamide. 7) Pipeline according to one or more of claims 1) - 6) characterized in that the thermoplastic pipe (1) and/or (6) represents a multilayer pipe. 8) Pipeline according to one or more of the claims D - 7) characterized in that the elastomer hose (2) or the elastomer molded part (4) consists of the elastomer quality X-NBR or its modifications. 9) Pipeline according to one or more of the claims D - 8) characterized in that the geometric conditions in the bonded area (3) or the overlapping areas (7.1 and 7.2) plus the attachment areas (8) are each 0.5 = 1/d = 3.