CH710986A1 - Connection arrangement with a connector and a thermally insulated pipe. - Google Patents

Abstract

In a connection assembly comprising a thermally insulated conduit (2) and a fitting (10) having a sleeve-like member (9) engaging the thermal insulation (3), this member is formed of a polymer containing polyketones or of polyketones consists. It has been found that such an element is resistant to the components of thermal insulation.

Description

Field of invention

The invention relates to a connection arrangement comprising a connection device and a thermally insulated pipe, wherein the thermally insulated pipe at least one inner pipe, at least one around the inner pipe arranged thermal insulation, which in particular consists of a polyurethane foam or comprises a polyurethane foam, and preferably one around has an outer jacket arranged around the thermal insulation, and wherein the connection device comprises a connection body with a plug-in sleeve for insertion into the inner tube and a sleeve-like element for placement on the inner tube. The invention also relates to a connection device for such a connection arrangement. The invention also relates to a method for connecting a thermally insulated conduit pipe to a connection body.

background

There are thermally insulated pipes are known which have an inner pipe for the medium to be conducted, wherein the inner pipe is surrounded for thermal insulation with an insulating layer. As a rule, an outer jacket is also provided. The inner tube can consist of plastic and e.g. be a pipe made of cross-linked polyethylene (PEx). The insulation layer usually consists of foamed polyurethane (PU). However, foamed thermoplastics such as polyethylene are also used. The outer jacket, if present, can also consist of plastic and the conduit pipe can be provided with a corrugation in order to improve its flexibility, or it can be smooth on the outside. The outer jacket can also be made of metal. A method for producing such pipes or such a pipe is known in particular from EP-A 0 897 788. Heat-insulated conduit pipes of the type described are e.g. used in heating networks, drinking water pipes, sewage pipes and cooling pipes.

In the end connection of a connector with such a pipe or with a similar thermally insulated pipe, the procedure is on the one hand so that the outer jacket and the heat insulation are removed in the connection area, whereby a short piece of the inner pipe is exposed. A connecting body of the connecting piece is then fastened in the inner pipe, for which a large number of procedures or configurations of connecting pieces are available.

A common procedure or a generic connection arrangement provides that first a sliding sleeve is pushed onto the pipe, then the plastic pipe is expanded with a tool, the connecting body is pushed into the expanded pipe and finally the sliding sleeve as a compression sleeve with the aid of a Tool is pushed in the direction of the pipe end over the inner tube, so that the socket of the connection body is fixed by pressing in the inner tube. The part of the inner pipe freed from the thermal insulation of the conduit is later insulated again, it being known to be arranged in a shell which is then foamed with a heat-insulating material.

In WO 2011/009 598 A1 a generic connection arrangement is proposed to improve the procedure, in which a plug-in sleeve of the connector is inserted into the inner tube and a calibration ring is hammered into the inner tube from the outside. In WO 2013/110 204 A1, another generic connection arrangement with a connection piece is proposed, in which a clamping sleeve is inserted between the inner tube and the thermal insulation. Such connection arrangements allow a very efficient procedure, since the thermal insulation at the end of the conduit does not have to be removed.

In any case, the materials from which the sleeve and the clamping ring are made must be able to withstand the not inconsiderable forces. For this reason, high-performance plastics are used, especially polyarylsolfones and polyvinylidene difluoride (PVDF) are common. The disadvantage in both cases is the high price of these polymers. The insignificantly cheaper polyarylsulfones have the disadvantage that they tend to form stress cracks. In many cases, the thermal insulation consists of PU foam. This is formed during the manufacturing process in a chemical reaction from the isocyanate component and the so-called polyol component. It is known that polyarylsulfones can form stress cracks in contact with PU foam or its starting components.

Presentation of the invention

It is the object of the invention to create a connection arrangement with a connector and a thermally insulated conduit which does not have the disadvantage mentioned.

[0008] This is achieved by a connection arrangement with the characterizing feature of claim 1.

It has been shown that by designing the sleeve-like element in such a way that it is formed from a polymer which contains polyketones or consists of polyketones, cracks in the sleeve-like element can be avoided.

The connection body is preferably also formed from a polymer which contains polyketones or consists of polyketones. It can thus be ensured that this element of the connection arrangement is also not impaired by the action of substances which are in the PU foam.

It is preferred that the polymer contains 50-100% by weight, preferably 90-100% by weight, of structural units of the formula (I)

Where R 1 and R 2 independently of one another represent alkyl, in particular ethyl and propyl, or

[0013] where R 1 is alkyl ether or aryl ether and R 2 is alkyl or aryl.

In one embodiment of the invention, the sleeve-like element is designed as a compression sleeve, which is pushed over the widened end region of the inner tube.

In a further preferred embodiment of the connecting arrangement, the sleeve-like element is arranged as a clamping sleeve between the outer wall of the inner tube and the insulating layer. This allows a reproducible secure attachment of the clamping sleeve. Furthermore, a design of the connection arrangement is preferred in which the connection body forms a stop for the end face of the inner pipe and the connection body carries a retaining ring which at its one end forms a second stop for the end face of the conduit pipe and which attaches to the connection body at its other end is, wherein the clamping sleeve engages over the retaining ring and has an internal thread and a rear collar, and in which the clamping sleeve is screwed onto the inner tube. Such a design results in a very simple and reliable connection between the conduit and the connector. The retaining ring can also be formed from the aforementioned polymer with polyketones.

It is preferred that the retaining ring forms an indicator in that the other end of the retaining ring can be seen when the clamping sleeve is screwed sufficiently far onto the inner tube. A preferred embodiment comprises that the receptacle has a plurality of circumferential outer ribs which are at a changing distance from the front end of the receptacle along their circumference.

It is a further object of the invention to provide a connection device for a connection arrangement which does not have the disadvantage mentioned.

This is achieved with a connection device comprising a connection body with a plug-in sleeve and a sleeve-like element overlapping the connection body, in which the sleeve-like element is formed from a polymer which contains polyketones or consists of polyketones. This also results in the effect that the sleeve-like element made of or with polyketones in the insulating foam does not suffer any cracks or other damage.

The connection body is preferably also formed from a polymer which contains polyketones or consists of polyketones. It is further preferred that the polymer contains 50-100% by weight, preferably 90-100% by weight, of structural units of the formula (I)

Wherein R 1 and R 2 independently of one another represent alkyl, in particular ethyl and propyl, or

[0021] where R 1 is alkyl ether or aryl ether and R 2 is alkyl or aryl.

A preferred embodiment of the connection device is arranged on the connection body retaining ring, which has a stop with a stop surface at one end, which is intended for the end face of an inner tube of a thermally insulated pipe, and a fastening means at its other end has, by means of which the retaining ring is attached to the connector body. The retaining ring can also be formed from a polymer which contains polyketones or consists of polyketones, in particular to the stated% by weight of the aforesaid polymer according to the above structural formula.

[0023] Another object of the invention is to create a method which avoids the mentioned disadvantages of crack formation.

This is achieved by a method according to claim 14.

Brief description of the drawings

[0025] Further refinements, advantages and applications of the invention emerge from the dependent claims and from the description that follows based on the figures. 1 shows a sectional view through the end of a thermally insulated conduit pipe with a connection piece fastened thereon according to an embodiment of the invention before a sleeve-like element (clamping sleeve) is completely inserted between the insulation and the inner pipe; FIG. 2 shows a sectional view according to FIG. 1 with a completely inserted sleeve-like element or a clamping sleeve completely screwed on; 3 shows a diagrammatic view of the clamping sleeve with the internal thread and with a tool engaging the clamping sleeve; 4 shows a simplified representation of a further embodiment with a sleeve-like element which is arranged on the exposed inner pipe of the conduit pipe and which serves as a displaceable compression sleeve; FIG. 5 shows the illustration of FIG. 4 with the end position of the compression sleeve; and FIG. 6 shows the illustration of FIG. 5 with an indicated shell and thermal insulation introduced into it.

Ways of Carrying Out the Invention

1 and 2 show a sectional illustration through the end region of a thermally insulated conduit pipe, the longitudinal axis L of the conduit pipe lying in the plane of the section. To simplify the figure, only the part of the rotationally symmetrical conduit and of the connection piece, which is essentially rotationally symmetrical in the connection area, is shown above the longitudinal axis L. The connection piece can have any known design or function as a pipe coupling or armature or as a fitting and can be designed accordingly outside its connection area shown with the conduit pipe. In particular, the connection piece at the other end can be configured in the same way as at the end shown. The conduit pipe in each case has thermal insulation or thermal insulation (not shown in full thickness) surrounding the inner pipe, and it preferably has an outer jacket. In particular, the thermal insulation and the outer jacket are corrugated. Such a conduit pipe can in particular be designed or manufactured according to EP-A 897 788.

The line pipe 1 is made with the foamed thermal insulation or insulation layer 3, which is usually formed from a polyurethane foam and optionally with the outer jacket 4 made of plastic. The thermal insulation surrounds the inner pipe 2 and rests against its outer wall 6. To simplify the drawing, the conduit is not shown as a corrugated pipe, but as a smooth pipe. The fitting can be used with either type of pipe. At the end of the conduit 1, a connection piece 10 shown as a preferred example is attached in the manner described below. A differently designed connection piece can also be used, which likewise has a sleeve-like element that is designed for placement between the inner pipe and the thermal insulation of the conduit pipe. For example, an embodiment according to EP 2 457 011 B1 can be provided.

In the preferred embodiment, the connection piece 10 has a connection body 11 which is provided with a plug-in sleeve 13 which is designed to be inserted into the inner tube 2 of the conduit pipe. Thus, the outside diameter of the socket is adapted to the inside diameter of the inner tube 2, so that a precisely fitting insertion can take place and the socket achieves a fluid-tight connection with the inner wall of the inner tube. In the preferred embodiment shown, the socket 13 has ribs 23, which will be explained below. The plug-in sleeve could additionally or instead be provided with other sealing means, in particular with at least one O-ring.

Subsequent to the plug-in sleeve 13, the connection body 11 has a stop 12 which, when the plug-in sleeve 13 is fully inserted, comes to rest on the end face 5 of the inner tube 2. A retaining ring 14, which in particular has the Z-shape visible in the cross-section in FIGS. 1 and 2, is arranged on the connection body 11. The retaining ring 14 forms a second stop 15 for the end face of the inner pipe 2 and rests with the stop surface 16 on the end face 5 when the connection between the conduit pipe and the connector has been made. The stop 15 of the retaining ring 14 is e.g. designed as a continuous annular flange, but could also have interruptions. In the position of FIG. 1, the stop surface 16 of the stop 15 is not yet in close contact with the end surface 5 of the inner tube 2, but is still slightly spaced therefrom. In the position of FIG. 2, the surface 16 of the stop 15 then rests against the end surface 5 of the inner tube 2. The retaining ring is fastened to the connection body 11 at its other end 17 facing away from the stop 15. In the example shown, this attachment is designed such that a flange 27 of the retaining ring 14 engages in a correspondingly designed groove in the connection body 11, as can be seen in FIGS. 1 and 2. This flange 27 can also be annular and continuous, but could also have interruptions. The attachment of the end 17 of the retaining ring to the connection body 10 can also be done by screwing, riveting, gluing or welding. Between the stop 15 and the flange 27 or the end 17 of the retaining ring 14 extends an annular retaining ring part 18, which can be designed without interruption or with interruptions and which is not rigidly connected to the connector body 11 and can thus expand under tension. This part does not have to lie directly on the connection body 11 either. The retaining ring 14 is preferably made of a plastic.

The sleeve-like element 9, which comes to lie between the inner tube 2 and the thermal insulation, is arranged on the connecting body 11 above the retaining ring 14. In this example, this sleeve-like element is designed as a clamping sleeve 9. The clamping sleeve 9 has a sleeve part with an internal thread 8. This internal thread is adapted to the external diameter of the internal tube 2 so that the clamping sleeve can be screwed onto the internal tube. The internal thread has a configuration, in particular a rounding of the thread turns, which is conducive to rolling the thread turns on the outer skin of the inner tube and thereby avoids cutting into the outer skin of the inner tube 2 as much as possible. Damage to the inner tube 2 is thus avoided as far as possible. At the rear end (seen in the screwing-in direction) of the clamping sleeve 9, a substantially annular collar 19 is provided which rests on the connection body 11. At this end of the clamping sleeve 9, a means of engagement for a tool is also provided, which will be explained below so that the sleeve 9 can be screwed onto the inner tube with the aid of the tool. In another embodiment of the connection piece, instead of a clamping sleeve that can be screwed onto the inner tube, a sleeve-like element can be provided, which is pressed between the inner tube and the thermal insulation.

In FIG. 1 it is shown that the plug-in sleeve 13 has been pushed into the inner tube 2. The clamping sleeve 9 has already been partially screwed onto the inner tube 2. It displaces the heat insulating insulation 3 of the pipe. This can be facilitated by a special design of the clamping sleeve, which will be explained later. The clamping sleeve 9 is screwed on further until its collar 19 comes to rest with its stop surface 29 on the stop surface 26 of the stop 15 of the retaining ring 14. If the clamping sleeve 9 is screwed a little further onto the inner tube 2, the stop 15 is pressed against the end face 5 of the inner tube 2 by the clamping sleeve 9 and the previously mentioned slight distance between the stop surface 16 and the end surface 5 is closed. This can be seen in FIG. The retaining ring 14 is thus elastically deformed in its area 18 and the attachment of the retaining ring 14 with its end 17 on the connection body 11 also presses the connection body 11 with its stop against the end face 5 of the inner tube.

According to the present invention, the sleeve-like element, which is arranged between the inner pipe 2 and the thermal insulation 3, and which is the clamping sleeve 9 in the present example, is formed from a polymer which contains polyketones or consists of polyketones. Accordingly, the polymer comprises polyketones and blends of polyketones. Polyketones are known materials and are characterized by the keto group (C = 0) in the polymer chain. Polyketones thus comprise polymers which contain 50-100% by weight, preferably 90-100% by weight, of structural units of the formula (I)

The term polyketones encompasses the simple polyketones (PK) in which R 1 and R 2, independently of one another, each represent alkyl (such as 1,2-ethyl and 1,2-propyl). Simple polyketones can be obtained by catalytically converting carbon monoxide with the corresponding alkenes, such as propene and / or ethene. Such polyketones are commercially available, for example, under the trade name Akrotek.

The term polyketones also includes the polyether ketones (PEK) in which R 1 is alkyl ether or aryl ether and R 2 is alkyl or aryl. Polyetherketones also include polymers such as polyetheretherketones (PEEK) and polyetherketoneketone (PEKK). Polyether ketones can be obtained, for example, by reacting bi-substituted alkyl or aryl ketones with diols or biphenols. Such polyketones are commercially available, for example, under the trade name Victrex.

The term alkyl stands in particular for unsubstituted C1-C4 alkyl; the term aryl stands in particular for phenyl and naphthyl.

The formation of the sleeve-like element from or comprising polyketones results in a high level of security against cracking in this element and thus against failure of the connector.

The connection body 11 can also be formed from the above polyketone-containing polymer or from the above polymer consisting of polyketones. The retaining ring 14 may also be formed from the above polyketone-containing polymer or from the above polymer composed of polyketones.

To facilitate the introduction of the sleeve-like element 9 into the thermal insulation 3, it can be partially or completely removed beforehand with a tool in the area around the inner tube in which the sleeve-like element is introduced or comes to rest after the introduction. However, the sleeve-like element itself can also have means which facilitate introduction. 3 shows an example of the clamping sleeve 9, in which this has cutting means 39 which cut the heat-insulating insulation 3 when the clamping sleeve is screwed onto the inner tube 2. This makes screwing easier. Furthermore, FIG. 3 shows an example of the engagement means on the clamping sleeve, which in this case consists of a toothing 34 on which a corresponding tool 35 with a counter toothing 36 can be attached. This tool also has receptacles 37 (only one is visible in FIG. 4) into which an actuating member can be inserted in order to rotate the clamping sleeve 9 for screwing on. Of course, the design of the tool can also be such that the clamping sleeve 9 can be screwed on by a motor.

The invention can also be carried out in other ways. In particular, it is possible to proceed with a connection device with a sliding sleeve and with an expansion of the inner tube, according to the method explained in the introduction as known. This is explained here only briefly with reference to the roughly schematic FIGS. 4 to 6, since it is known to the person skilled in the art. Thus, the outer jacket 4 of the thermally insulated conduit pipe is first cut and peeled off and the thermal insulation 3 or the insulation foam is then removed mechanically as far as necessary. A sliding sleeve of the connection device is then pushed onto the exposed inner tube 2 as its sleeve-like element 9. This sliding sleeve or the sleeve-like element is formed from a polymer which contains polyketones or consists of polyketones. There follows a step in which the inner tube 2 is widened at the end with a tool, which is not shown here. The plug-in sleeve 13 of the connection body 11, which is preferably also formed from a polymer which contains polyketones or consists of polyketones, is then inserted into the widened end of the inner tube 2. Subsequently, the sliding sleeve is pushed again in the direction of the free end of the inner tube 2 over the widened area with the help of a tool and this is pressed together again by the sliding sleeve so that the connection body 11 with the plug-in sleeve 13 is mechanically fixed by the press connection in the inner tube 2. At least the part of the inner pipe that has been freed from the thermal insulation is then insulated again, which can be done in such a way that this part of the inner pipe and, as a rule, also the parts of the connection device protruding from the inner pipe are arranged in a closed shell, only indicated by the rectangle 30, which is then foamed with the insulating material 31 in a known manner. The sliding sleeve comes to lie in the heat-insulating material 31 and other parts of the connection device may come to lie in the heat-insulating material and come into contact with the insulation foam or its starting components (isocyanate and polyol). Preferably, all parts of the connection device that come into contact with the heat-insulating material are formed from a polymer which contains polyketones or consists of polyketones. The explanations given above regarding the polyketones and their formula also apply to this exemplary embodiment.

The stress cracking resistance of the plastic polyketone to the action of isocyanate or polyol has been confirmed in tests. Test specimens made of RIAMAXX HR XE4355 KTW-M polyketone were immersed in a bath made of isocyanate or in a bath made of polyol at room temperature and under bending stress. Then tensile tests were carried out in comparison with untreated polyketone test specimens. Test specimens immersed in isocyanate showed after 48 hours of immersion and after 16 days of immersion and after 62 days of immersion and also after 121 days (4 months) no deviation in the properties in the tensile test compared to untreated test specimens made from the polyketone. Likewise, the test specimens immersed in polyol after 1 month immersion in polyol and after 2 months immersion in polyol showed no deviation in the properties in the tensile test compared to untreated test specimens.

In summary, it can be said that in a connection arrangement which comprises a conduit with an inner pipe, thermal insulation and a connection device which has at least one connection part coming to lie in the thermal insulation, this connection part is formed from a polymer which contains polyketones or of polyketones. Other parts of the connection device can also be formed from the polymer containing polyketones or from the polymer consisting of polyketones.

Claims (15)

1. Connection arrangement comprising a connection device (10) and a thermally insulated conduit pipe (1), the thermally insulated conduit pipe having at least one inner pipe (2), at least one thermal insulation (3) arranged around the inner pipe, which in particular consists of a polyurethane foam or in particular comprises a polyurethane foam, and preferably has an outer jacket (4) arranged around the thermal insulation, and wherein the connection device (10) has a connection body (11) with a socket (13) for insertion into the inner tube and a sleeve-like element (9) which is designed for placement on the inner tube, characterized in that the sleeve-like element (9) is formed from a polymer which contains polyketones or consists of polyketones. 2. Connection arrangement according to claim 1, characterized in that the connection body (11) is formed from a polymer which contains polyketones, or consists of polyketones. 3. Connection arrangement according to claim 1 or 2, characterized in that the sleeve-like element is a clamping sleeve (9) which is arranged between the outer wall (6) of the inner pipe (2) and the insulating layer (3) of the conduit pipe (1) and is made of the thermal insulation layer of the conduit protrudes. 4. Connecting arrangement according to claim 1 or 2, characterized in that the sleeve-like element (9) is a compression sleeve which rests on the outer wall of the inner pipe in a region of the pipe in which the thermal insulation layer (3) of the pipe is removed and subsequently replaced applied thermal insulation (31) has been replaced. 5. Connection arrangement according to one of claims 1 to 3, characterized in that the connection body (11) forms a stop (12) for the end face (5) of the inner tube (2), that the connection body (11) carries a retaining ring (14) which at one end forms a second stop (15) for the end face (5) of the conduit pipe and which is fastened at its other end (17) to the connection body (11), the sleeve-like element (9) holding the retaining ring (14) overlaps, and that the retaining ring is formed from a polymer which contains polyketones or consists of polyketones. 6. Connecting arrangement according to claim 5, characterized in that the sleeve-like element is designed as a clamping sleeve and has an internal thread (8) and a rear collar (19), and that the clamping sleeve (9) is screwed onto the inner tube (2). 7. Connection arrangement according to one of claims 1 to 6, characterized in that the polymer contains 50-100% by weight, preferably 90-100% by weight, of structural units of the formula (I) where R 1 and R 2 independently of one another represent alkyl, in particular ethyl and propyl, or where R 1 is alkyl ether or aryl ether and R 2 is alkyl or aryl. 8. Connecting arrangement according to one of claims 4 to 6, characterized in that the retaining ring (14) forms an indicator in that the other end (17) of the retaining ring (14) becomes visible when the clamping sleeve (9) is sufficiently far onto the inner tube (2) is screwed on. 9. Connection arrangement according to one of claims 1 to 8, characterized in that the socket (13) has a plurality of circumferential outer ribs (23) which have an alternating distance from the front end (33) of the socket along their circumference. 10. Connection device (10) for a connection arrangement according to one of claims 1 to 9, comprising a connection body (11) with a plug-in sleeve (13) and a sleeve-like element (9) which extends radially at a distance from the plug-in sleeve of the connection body (11), characterized in that that the sleeve-like element is formed from a polymer which contains polyketones or consists of polyketones. 11. Connection device according to claim 10, characterized in that the connection body (11) is formed from a polymer which contains polyketones or consists of polyketones. 12. Connection device according to one of claims 9 or 10, with a retaining ring (14) which is arranged on the connection body (11) and has a stop (15) with a stop surface (16) at one end, which is for the end face (5) an inner pipe of a thermally insulated conduit pipe is determined, and which has a fastening means (27) at its other end (17) by means of which the retaining ring (14) is attached to the connecting body (11), characterized in that the retaining ring is formed from a polymer is, which contains polyketones or consists of polyketones. 13. Connection device according to one of claims 10 to 12, characterized in that the polymer contains 50-100% by weight, preferably 90-100% by weight, structural units of the formula (I) where R 1 and R 2 independently of one another represent alkyl, in particular ethyl and propyl, or where R 1 is alkyl ether or aryl ether and R 2 is alkyl or aryl. 14. A method for connecting a thermally insulated conduit pipe (1) to a connection body, which has an inner pipe (2), thermal insulation (3) and preferably an outer jacket (4), and wherein the connection body (11) is attached to the conduit pipe by a plug-in sleeve (13) of the connection body is inserted into the inner pipe and a sleeve-like element (9) is placed on the inner pipe, whereby the connection body is fixed on or in the conduit pipe, characterized in that the sleeve-like element (9) is formed from a polymer, which contains polyketones or consists of polyketones. 15. The method according to claim 14, characterized in that the polymer contains 50-100% by weight, preferably 90-100% by weight, structural units of the formula (I) where R 1 and R 2 independently of one another represent alkyl, in particular ethyl and propyl, or where R 1 is alkyl ether or aryl ether and R 2 is alkyl or aryl.