CH632574A5 - PIPE CONNECTION WITH TWO PIPE ENDS. - Google Patents

Description

The invention relates to a pipe connection with two pipe ends, in which either the one pipe end as a thermoplastic-coated pipe insertion end is arranged in a socket-shaped extension serving as a receiving pipe section of the other pipe end or both pipe ends as a thermoplastic-coated insertion pipe ends in one serving as receiving pipe sections for these pipe insertion ends Connection sleeve are held, the inner wall of the receiving tube section or the receiving tube sections with a thermoplastic

Are plastic coated, and in which a heatable insert body is arranged in the annular gap between the respective insertion tube end and the respective receiving tube section.

Particularly in the case of plastic-coated metal pipes for installation technology, it is necessary to connect pipe ends tightly and at the same time in a pressure-resistant manner and to ensure sufficient elasticity and elasticity for the respective application in order to avoid damage to the connection caused by use. The receiving pipe section of such connections is either formed by a sleeve-shaped widening of the one pipe end, or two opposite receiving pipe sections are formed in a suitable connecting sleeve, that is to say in a fitting or a so-called double sleeve. The invention is based on such so-called plug-in socket connections.

It is already known (OE-PS 239 018, CH-PS 507081) to use a heatable insert body in the form of a heating insert embedded in the pipe sleeve, which contains metallic and electrically fed heating wires, for connecting plastic pipes made entirely of a thermoplastic. Such plastic insert bodies with electrical heating elements on the one hand require a not inconsiderable manufacturing outlay, including the connection terminal or the like to be led out of the connection, and on the other hand require the provision and connection of a special electrical voltage source at the construction site, which involves careful assembly work with electrical sources. Thirdly, in these known connecting devices, it is necessary in many applications to introduce additional locking bodies to increase the mechanical strength of such connections.

The invention has for its object to provide a device of the type specified in particular for plastic-coated metal pipes, in which a very simple insert body can be used without additional heating elements and can be heated accordingly easily and which requires no additional locking means and sealing means except the insert body. Rather, the insert body should not only enable fusion welding of the connection, but also additionally ensure a mechanical and, in particular, pressure-tight locking of the connection. The insert body itself and the work required to establish the connection are to be simplified as much as possible.

This is achieved according to the invention in that the heatable insert body is designed as an insert sleeve made entirely of a heat-conducting material, the outer end of which is directed towards the edge of the receiving tube section and extends beyond this edge in the longitudinal direction of the tube, and that the insert sleeve extends in its annular gap Area is provided with openings arranged distributed over its circumference. The insert sleeve expediently consists of a good heat conductor, in particular of aluminum or its suitable alloys. The end protruding over the edge of the receiving tube section itself serves to introduce the heat into the insert sleeve without additional contacting measures, in particular using suitable heating tongs or the like, which can simply be placed on the construction site. After inserting the insert sleeve into the receiving tube section and inserting the insert tube end, the insert sleeve is heated up in this way. As a result of the heating of the insert sleeve, the plastic layers of the receiving tube section and of the insert tube end that are facing each other melt. The molten plastic fills the annular gap in a homogeneous weld and thereby passes through the openings in the insert sleeve. This amalgamation and the connection established through the breakthroughs will make it a secure and

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achieved mechanical locking of the entire connection. With a suitable choice of plastics, the required sealing of the connection can also be achieved. After the plastic mass has solidified within the annular gap, a pipe connection is produced which, depending on the choice of plastic, has the desired thermal, chemical and mechanical strength, without additional sealing or locking means having to be introduced into the annular gap. The insert sleeve takes on both the function of the heating element and the locking function.

The described advantages of the invention have a very particular effect if, according to one embodiment of the invention, at least the outer coating of the insert tube end consists of a thermoplastic elastomer containing blowing agent, that is to say a so-called thermoplastic rubber. During the heating of the insert sleeve as described, this elastomer of the outer coating of the insert tube end expands and at the same time fills the entire annular gap elastically with the melted plastic layer of the receiving tube section, in particular it simultaneously brings through the openings in the insert sleeve, so that overall there is an elastic and at the same time firm and locked connection results, which also has a high sealing effect. If thermoplastic elastomers with a high melting point are used, a reliable locking and sealing system is also obtained with so-called hot pipes. Such a connection can meet high thermal, chemical and mechanical requirements.

According to a further embodiment of the invention, a particularly expedient design of the insert sleeve and the connection results when the outer end of the insert sleeve engages over the edge of the receiving tube section in a cap-like manner. On the one hand, this results in a particularly closed design of the connection, since the insert sleeve covers the entire annular gap, including the edge of the receiving tube section. On the other hand, in the melting process described, the plastic mass can also penetrate into the space between the edge of the receiving tube section and the overlapping section of the insert sleeve and bring about an additional seal. A particularly good mechanical termination of the connection is thus achieved. On the other hand, if the overlapping part of the insert sleeve is in heat-conducting contact with the edge of the receiving tube section, it is also possible to heat at least this edge via the insert sleeve and thus favor the melting process in the upper region. Finally, a particularly expedient attachment surface for the respective heating tool, in particular heating tongs, is achieved.

In a further embodiment of the invention, the inner end of the insert sleeve expediently overlaps the end face of the insert tube end. In this way, on the one hand, a safe insertion limitation for the insertion tube end is formed, in particular also in cooperation with the overlapping of the edge of the receiving tube section. On the other hand, a secure closure of the annular gap is achieved at the bottom, so that no molten plastic mass can enter the interior of the line.

According to a further embodiment of the invention, the outer end of the insert sleeve, which extends over the edge of the receiving tube section, is provided with control openings which are distributed around the circumference and which open out into the annular gap on the inside. These control breakthroughs are also filled by the molten plastic mass and, as soon as molten plastic mass emerges, in particular the expanding elastomer, make the completed melting process visible, so that the heating process can be ended in good time.

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In order to promote the locking action of the insert sleeve, it is expedient if, in a further embodiment of the invention, the insert sleeve is provided on its inner and outer circumference with projections, in particular ring gearing, which oppose each other and oppose an opening movement of the connection.

According to a further embodiment of the invention, the insert sleeve is conically tapered inwards at least on its outer wall in the annular gap. This achieves a certain self-clamping effect of the insert sleeve, which promotes the sealing and locking effect.

If the invention is used in a connecting device in which two insertion tube ends are surrounded by a connecting sleeve (fitting, double sleeve) each having an associated receiving tube section, then, according to a further embodiment of the invention, an annular compensating body made of elastic is expediently located between the mutually facing inner ends of the insert sleeves Plastic, in particular an elastomer, arranged. This further improves the ability of the connection to absorb vibrations and strains.

The connection designed according to the invention and in particular the insert sleeve has the further advantage that manufacturing tolerances of the pipes to be connected and in particular of the push-in pipe end and the receiving pipe section or the receiving pipe sections are recorded. This compensating effect can be increased due to the good locking and sealing effect achieved by the invention, if the receiving tube section is provided with longitudinal waves.

Further details and advantages of the invention result from the claims and the following description of an embodiment of the invention with reference to the drawing.

The drawing shows a half longitudinally sectioned side view of a connecting device according to the invention.

In the illustrated embodiment of the invention, two smooth pipe insertion ends 1 and 2 made of metal material, for. As steel or aluminum, connected to each other, for which purpose a receiving tube section 3 or 4 on a common connecting sleeve 5 made of metallic material, for. B. steel or aluminum are provided. The connecting sleeve 5 therefore forms a fitting or a double sleeve. The plug-in tube ends 1 and 2 are coated on the inside and outside with plastic, the outer coatings denoted by 6 consisting of a thermoplastic elastomer containing blowing agent. The connecting sleeve 5 is also coated on the inside and outside with plastic, at least the inside coating 7 being made of a thermoplastic material whose essential properties correspond to the plastic of the outside coating 6 of the insert tube ends 1 and 2.

In each case in the annular gap between the insertion tube end 1 or 2, an insert sleeve 8 is arranged, which is formed entirely from a heat-conducting material, in particular from a good heat conductor such as aluminum or its alloys. As shown in the upper part of the drawing to simplify the drawing, the outer end of the insert sleeve 8 overlaps the edge 5a of the respective receiving tube section 3 or 4 of the connecting sleeve 5 in a cap shape. The part 9 of the insert sleeve 8 which surrounds the edge lies directly on the inside against the outer wall of the edge 5a, so that heat transfer is also formed there. As the upper part of the drawing clearly shows, the outer end of the insert sleeve 8 facing the edge 5a of the receiving tube section 3 or 4 extends in the tube longitudinal direction beyond this edge 5a, in the exemplary embodiment with a cap-shaped configuration. The outer wall of this outside the annular gap

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lying part of each insert sleeve 8 is used to abut the heating tool used, z. B. a heat gun.

Each insert sleeve 8 is provided in its area running in the annular gap between the insertion tube end 1 or 2 and the receiving tube section 3 or 4 with openings arranged distributed over its circumference. Furthermore, the outer end of each insert sleeve 8, which extends over the edge of the receiving tube section 3 or 4, is provided with control openings 11 which are distributed over the circumference and which open into the inner annular gap, as the drawing shows.

Each insert sleeve 8 also has on its inner and outer circumference in opposite directions and an opening movement of the connection projections 12 in the form of ring teeth. Finally, each insert sleeve 8 is conically tapered on its outer wall in the annular gap, e.g. with an inclination angle of approx. 30 °.

If the insert sleeves 8 and the insert tube ends 1 and 2 are pushed into the respective receiving tube sections 3 and 4 of the connecting sleeve 5 in the manner shown in the drawing, then the insert sleeve is attached using a suitable heating tool that acts on the free outer end of the insert sleeves 8 8 warmed. Since the insert sleeves 8 are made of a material which is a good heat conductor, in particular a suitable metal,

consist, the entire insert sleeve 8 is heated uniformly. This heating causes the facing plastic layers 6 and 7 to melt. If elastomer containing blowing agent is used, this plastic expands. The 5 heated and melted plastic fills the entire annular gap and passes through the openings 10, so that there is a homogeneous welding of the entire plastic mass located in the annular gap, the openings 10 forming a kind of multiple reinforcement after the plastic mass has solidified. During the heating and melting process, plastic material also enters the control openings 11 from the annular gap. As soon as this plastic mass is visible from the outside in the control openings, this signals the end of the melting process and the heating 15 can be set.

As the drawing shows, the inner end of each insert sleeve 8 also overlaps the end face of the associated insertion tube end 1 or 2, as shown at 13. When using the connecting sleeve 5 20 shown in the drawing with two mutually opposite receiving tube sections 3 and 4, an annular compensating body 14 made of elastic plastic, in particular an elastomer, is arranged between the mutually facing inner ends 13 of the insert sleeves 8.

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Claims (8)

632 574 PATENT CLAIMS 1.Pipe connection with two pipe ends, in which either the pipe end as a pipe insertion end coated with a thermoplastic is arranged in a socket-shaped extension of the other pipe end serving as a receiving pipe section, or both pipe ends as a plug-in pipe ends coated with a thermoplastic plastic in a connecting sleeve serving as receiving pipe sections for these pipe insertion ends are held, wherein the inner wall of the receiving tube section or the receiving tube sections are coated with a thermoplastic, and in which a heatable insert body surrounding the insert tube end is arranged in the annular gap between the respective insert tube end and the characterized, characterized in that the heated insert body as an insert sleeve (8) formed entirely from a heat-conducting material is formed, the outer sleeve of which faces the edge (5a) of the receiving tube section (3, 4) seres end extends in the longitudinal direction of the tube beyond this edge, and that the insert sleeve is provided in its area running in the annular gap with openings (10) distributed over its circumference. 2. Pipe connection according to claim 1, characterized in that at least the outer coating (6) of the insertion tube end (1,2) consists of a blowing agent-containing thermoplastic elastomer. 3. Pipe connection according to claim 1 or 2, characterized in that the outer end of the insert sleeve (8) overlaps the edge (5a) of the receiving tube section (3, 4) in a cap shape. 4. Pipe connection according to one of claims 1 to 3, characterized in that the inner end (13) of the insert sleeve (8) engages over the end face of the insertion tube end (1, 2). 5. Pipe connection according to one of claims 1 to 4, characterized in that the outer, over the edge of the receiving tube section (3,4) extending end of the insert sleeve (8) is provided with control openings (11) distributed over the circumference, which open into the annular gap on the inside. 6. Pipe connection according to one of claims 1 to 5, characterized in that the insert sleeve (8) is provided on its inner and outer circumference with projections (12), in particular ring gearing, which face in opposite directions and an opening movement of the connection. 7. Pipe connection according to one of claims 1 to 6, characterized in that the insert sleeve (8) is at least on its outer wall in the annular gap tapered inwards. 8. Pipe connection according to one of claims 1 to 7, in which both pipe ends are formed as push-in pipe ends and are each surrounded by an associated receiving tube section having a connecting sleeve, characterized in that between the mutually facing inner ends (13) of the insert sleeve (8) an annular Compensating body (14) made of elastic plastic is arranged.