CH711285B1 - Shunting for the connection of a first pipe section with connection sleeve with a second pipe section with a spigot. - Google Patents

Abstract

Anti-thrust device (18) for connecting a first tube section (1) with a connection sleeve (3) to a second tube section (4) with an insertion end (5), the insertion end (5) being inserted into the connection sleeve (3) and the thrust protection device (3) 18) ensures a frictional and / or positive connection between an axial portion of the insertion end (5) and the connection sleeve (3). The at least formed as a circular ring segment Schubsicherung (18) is characterized in that it comprises a first, radially outwardly disposed metallic portion (33) which in connected first pipe section (1) and second pipe section (4) in frictional and / or positive contact with an inner wall portion (14) of the connection sleeve (3), and a second, radially inwardly disposed metallic region (34), which in connected first pipe section (1) and second pipe section (4) in frictional and / or positive contact with an outer wall portion (14) of the insertion end (5), wherein the first metallic portion (33) and the second metallic portion (34) are formed electrically isolated from each other.

Description

description

Technical field The present invention relates to connecting elements for electrically conductive, typically metallic pipe sections in the form of thrust protection devices. Furthermore, the present invention relates to methods for producing such shear protection and uses of such shear protection.

PRIOR ART If metallic pipes, preferably buried metallic pipes for the transport of water, natural gas, or other liquid or gaseous media, are connected to one another, care must be taken to ensure that they also remain in the ground for a very long time and below A slight and mechanically stable connection is always guaranteed in the event of slight earth movements.

For this purpose, a connection sleeve is formed in such pipes at one end of a respective pipe section, while the other end is designed as a free end without such a connection sleeve (or there are 2 different types of pipe sections, each with connection sleeves on both sides and such without any connections). The connecting sleeve serves as a receiving element for the free end of the next pipe section, the free end of the next pipe section is pushed into the connecting sleeve designed with a larger inside diameter and the two pipe sections are sealed on the one hand and, on the other hand, non-positively and / or positively and / or materially mechanically connected.

To facilitate this, there has long been a design according to the prior art, in which the connecting sleeve has at least two circumferential grooves on its inside. A circumferential elastic plastic seal is inserted into one of these grooves before inserting the free end, which is to ensure the tightness. In a second circumferential groove, generally located further back, viewed in the direction of insertion, a so-called thrust protection is also introduced: a metallic ring-shaped or ring-segment-shaped element which is intended to ensure the mechanical connection. In order to facilitate this connection, there is usually a circumferential weld bead on the outside at the insertion end, slightly offset from the front edge, which then comes to rest just in front of the insertion direction and typically comes into contact with the thrust protection. The connection via the thrust protection is typically made via a non-positive and / or positive connection; A cohesive connection is usually avoided in order to be able to separate the pipe sections again without destroying them.

DISCLOSURE OF THE INVENTION It is an object of the present invention, inter alia, to provide an improved connection of this type between metallic pipe sections, specifically to provide an improved thrust protection.

The present invention thus on the one hand a thrust protection device according to claim 1, a method for producing such an anti-shear device, a connection between two line sections using such an anti-shear device, and a method for producing such a connection.

Specifically, the present invention relates to a thrust protection for the connection of a first pipe section with a socket with a second pipe section with an insertion end, wherein the insertion end is inserted into the connection sleeve and the thrust protection is a non-positive and / or positive connection between an axial portion of the insertion end and the connection sleeve guaranteed.

The proposed, at least as a circular ring segment, preferably designed as a circumferential ring, thrust protection has a first, radially outer arranged metallic area which, when the first pipe section and the second pipe section are connected, preferably exclusively in non-positive and / or positive contact with an inner wall section Connection sleeve is standing and does not contact the second pipe section. In addition, the thrust protection has a second, radially internal metallic area, which, when the first pipe section and the second pipe section are connected, is in frictional and / or positive contact preferably exclusively with an outer wall section of the insertion end of the second pipe section and, in other words, does not contact the first pipe section , The thrust protection is designed in such a way that the first metallic region and the second metallic region are designed to be electrically insulated from one another.

The problem with such buried metallic lines can namely be the fact that they are electrically conductive between the different sections and over the entire line. On the one hand, the electrical conductivity over the entire line is generally undesirable in many areas, and on the other hand and in particular the electrical conductivity at the respective contact point between two line sections is problematic with regard to corrosion. In the past, the durability of water pipes made of ductile cast iron was primarily affected to a high degree by the electrical conductivity of the socket connection. Due to heterogeneous bedding of the pipes or due to the influence of external currents due to macro elements with external cathodes or due to the effects of stray currents, this electrical contact leads to the formation of galvanic corrosion. The effect of the longitudinal

CH 711 285 B1 conductivity is clearly shown by the significantly higher durability of cast iron pipes for gas, which are generally not designed to be electrically conductive.

[OO1O] The longitudinal conductivity of the pipelines was required in the past for the use of the water supply network as an earthing system. With the removal of this requirement, it is sensible in terms of long durability and corrosion technology to design the sleeve connection electrically insulating.

At high nominal pressure, as occurs, for example, in power plant constructions, non-positive sleeve connections are used. The retaining ring of the existing connecting elements is made of cast iron and thus represents an electrically conductive metal connection between two pipes, which can be problematic.

[0012] Certain approaches rely on plastic-based retaining rings. Experience shows, however, that although these ensure the electrical insulation effect, the mechanical loads in the multi-axis stress state are too high.

The solution in the present case is that the two functions "electrical insulation" and "mechanical load transfer" are separated within the retaining ring. It is important not only to achieve this separation with an outer coating of the retaining ring. Due to manufacturing tolerances, there are always point loads and overstressing of the coating, and ultimately ultimately contacting despite the coating. Such systems have therefore not proven themselves in the past.

For sustainable electrical insulation, it is essential to primarily subject the plastic component to compressive stresses and, if at all, only shear stresses. So that no damage from flowing processes is possible, a spatially cross-linked epoxy resin can be used with the plastic, which can also be mixed with quartz sand. The two halves of the retaining ring do not only have the function of the thrust protection. Rather, they are supposed to relieve the local stress peaks between the cast iron pipe, welding bead and retaining ring and introduce them evenly, mainly as compressive stress, into the insulating plastic component.

Ideally, the plastic component only has the function of connecting the individual components of the retaining ring and the electrical separating layer (in this case the quartz sand).

The electrical insulation can be achieved by an electrically insulating pressure-resistant material. The focus is on sand or glass fibers. But it is also conceivable to use cement mortar.

Accordingly, a first preferred embodiment of the proposed thrust protection is characterized in that the electrical insulation between the first metallic region and the second metallic region is designed as a continuous, essentially axially extending layer that electrically separates the two metallic regions from one another, wherein the first metallic region is arranged radially on the outside of this layer and the second metallic region is arranged radially on the inside of this layer. This layer is designed to be electrically non-conductive, which typically means that the material used has an electrical conductivity of less than 10 ^-8 S · m ^_1 .

[0018] Furthermore, the layer is preferably formed on the basis of a non-electrically conductive plastic material. This plastic material can be formed on the basis of a crosslinked or uncrosslinked polymer, which in particular can preferably be mixed with one or more fillers.

The material of the layer can preferably be a thermosetting polymer, preferably a crosslinked polymer based on phenol, bisphenol and / or aliphatic building blocks, particularly preferably in the form of an epoxy resin.

A further preferred embodiment is characterized in that the fillers in the plastic material of the insulating layer are glass fibers and / or particulate fillers, preferably with an average grain size (d50) in the range from 0.01-0.5 mm, particularly preferably with an average grain size (d50) in the range of 0.1-0.3.

[0021] The particulate fillers are preferably selected from the following group: ground glass, broken glass, glass balls, particulate inorganic mineral fillers. The particulate inorganic mineral fillers can be, for example, rock powder, silicates, carbonates, oxides, hydroxides. Sand is particularly preferably used, very particularly preferably quartz sand, as the particulate filler.

It is generally preferred that the proportion of filler, particularly preferably selected as quartz sand, in the insulating plastic layer between the two metallic areas in the range of 2-80 percent by weight, preferably in the range of 20-70 percent by weight, particularly preferably in the range of 50-60 percent by weight. A further preferred embodiment is characterized in that the layer, measured in the radial direction over the entire extent, has a thickness (d) of at least 0.1 mm, preferably in the range of 0.5-4 mm.

It is further preferred if the layer extends at least in sections axially and parallel to a main axis of the anti-thrust device, the layer either running axially and parallel or inclined, in sections even radially to this main axis, or only in one or more axial sections , and runs parallel to the main axis between these axial sections, these sections then preferably being radially offset, in

CH 711 285 B1 to which the section facing the free end of the insertion end is arranged radially further outwards, a vertical, curved or inclined layer region is arranged. Viewed in a radial sectional view, layer guides in the form of a horizontal or inclined straight line, stair-shaped or Z-shaped guides, or zigzag guides of this insulating layer are therefore possible.

Furthermore, the thrust protection can preferably be designed in the form of a circumferential ring, in which either individual ring segments are connected to one another via preferably elastic connecting elements, or in which the circumferential ring is constructed from circumferential one-piece elements.

The thrust protection can further preferably have a radially inner, axially extending circular cylindrical inner surface for non-positive and / or positive contact with the outer surface of the insertion end, as well as a radially outer, conically widening contact surface inclined to the axis for positive and / or positive contact with a preferably substantially correspondingly inclined inner contact surface of the connecting sleeve, the angle of inclination of the conically widening contact surface relative to the axis preferably being in the range of 10-45 °, in particular preferably in the range of 15-30 °.

The inner surface can be formed by the second metallic region and the contact surface by the first metallic region, preferably the first metallic region and the second metallic region being formed from the same material, preferably from iron or an iron alloy, for example as Cast iron or as a turned part, particularly preferably made of ductile cast iron or steel.

Furthermore, the present invention relates to a method for producing such a thrust protection.

This manufacturing method is preferably characterized in that the first and the second metallic region are manufactured in a first step in the form of encircling rings or in the form of partially encircling circular ring segments, and then (optionally after surface treatment of the rings in the area of the contact surface) insulating layer, for example using sandblasting and / or by chemical etching) the two areas are preferably connected to one another by a continuous axially extending layer, the layer electrically separating the areas from one another, and the first metallic area being arranged radially on the outside of this layer and the second metallic region is arranged radially on the inside of this layer. A preferred variant of this method is characterized in that the layer is formed as part of an entire coating of at least one of the areas in a coating process.

Furthermore, the present invention relates to a connection between two metal line sections using such a thrust protection, with a first and a second line section. The connection comprises a first and a second line section as well as the additional connecting elements, in particular the thrust protection, and optionally an elastic sealing element. In this case, a first line section has a connecting sleeve which has at least one radially inwardly open first chamber in the form of an at least partially circumferential groove, and preferably at least one further inwardly open chamber in the form of a circumferential groove for receiving an elastic seal, the the first chamber further preferably has a conically widening inner flank which contacts the thrust lock arranged in the first chamber via its first region. Furthermore, the second line section is inserted with its insertion end into the connecting sleeve, and contacts the thrust protection via its second area with a portion of the outer surface of the insertion end and preferably has a circumferential weld bead on the outside, which is used for axial contacting of the thrust protection, preferably at the inside thereof Insertion direction viewed front side, is provided.

Finally, the present invention relates to a method for producing a connection, as described above, preferably characterized in that, optionally after inserting an elastic seal, preferably in the form of a circumferential ring made of an elastic plastic material, in the Connection sleeve, the thrust lock is inserted into the first chamber, the thrust lock is widened with a mounting wedge if necessary, and then the insertion end is inserted into the connection sleeve along the axis until the welding bead comes to lie in front of the thrust lock in the insertion direction.

Further embodiments are specified in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are described below with reference to the drawings, which serve only for explanation and are not to be interpreted as restrictive. In the drawings:

1 shows an axial section through a connecting sleeve with an inserted insertion end at the end of a tube with an inserted seal and thrust protection.

2 different geometrical designs of thrust protection devices for different designs and sizes of connecting sleeves;

CH 711 285 B1

Fig. 3 shear protection with insulating layers, wherein 3a) shows an embodiment with a stepped insulating layer, in 3b) an embodiment with an inclined straight insulating layer and in 3c) an embodiment with an axial insulating layer;

Fig. 4 views of two thrust locks in the axial direction, in 4a) a construction in the form of a circumferential ring and in 4b) a construction in the form of circular ring segments connected by connecting elements, and

5 is a sectional view of a prototype, and

6 shows the results of the AC resistance measurements.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows an axial section of a connection between a first pipe section 1 with a connecting sleeve 3 and a second pipe section 4, which has an insertion end 5 without a connecting sleeve. The connecting sleeve 3 expands the interior 3 of the first pipe section 1 at the free end of the first pipe section, this expansion being formed gradually on the inside by the sleeve section running apart to a certain extent in a trumpet shape.

There is on the inside of the connecting sleeve 3, a first stage in the form of paragraph 9, where the inner diameter of the inner surface 8 is expanded in a first stage to an expanded inner surface 10, the inner diameter of which is slightly larger than the outer diameter of the insertion end 5 of the other line 4.

This is followed by a further expansion in terms of diameter in the form of the rear chamber 11 for the elastic seal. This rear chamber is to a certain extent a circumferential, open groove and serves to accommodate an elastic sealing ring 12 which is clamped in this chamber between the outer wall 7 of the pipe section 4 and this chamber 11 and thus ensures the seal between the two pipe sections. In order to mechanically hold this sealing profile 12 in this circumferential groove 11, a corresponding groove can be provided in the seal, into which a circumferential inward groove 19 engages in the outer wall of the chamber 11.

Further towards the end of the connecting sleeve, the diameter is tapered again, approximately to the inside diameter according to section 10, and then widens into an extension area 20, which serves to accommodate the welding bead 17 when the insertion end is pushed further in, if necessary. This is followed by a somewhat trapezoidal front chamber 13, which has an axial end wall in the form of the vertical section 15, and a conically widening inner flank 14, the conical widening now being understood in the insertion direction of the insertion end 5. This flank 14 lowers down to the front opening 16, the outside diameter of which is somewhat larger than the inside diameter in the region 10 described above. The connecting sleeve 3 is closed off by the front vertical surface of the front end 21.

In this connection sleeve 3, the insertion end of the second tube 4 is now inserted. Basically, an inner space 6 is enclosed there by the same inner diameter, and set back somewhat from the free end, this second tube has a circumferential welding bead 17 which projects beyond the cylindrical surface contour of the outer surface 7 of the wall of FIG. The function of this welding bead 17 will be explained below.

In the front chamber 13, an additional element, namely the approximately trapezoidal thrust lock 18, is now arranged.

If such a connection is made, the elastic circumferential seal 12 is inserted and positioned in the sleeve 3 in a first step. The thrust safety device 18 is then inserted and typically widened by a mounting wedge, which is possible since such thrust safety devices generally have a slight deformability in the radial direction. The free end 5 of the second line 4 is then pushed into the connecting sleeve, to the extent that the welding bead 17 comes to rest just behind (in the direction of insertion) the push lock 18. In this way, a non-positive and / or positive connection between the two line sections is effected. Pulling out without additional tools is impossible. This is done by trying to pull the line 4 out of the connecting sleeve 3, then the welding bead 17, as far as the friction of the lower surface 22 of the thrust protection on the outer wall 7 of the insertion end is not sufficient, is pushed back as far as possible against the thrust protection 18, and then the inclined surface of the thrust safety device 18 is pressed against the likewise inclined surface 17 in the front chamber. As a result, the anti-shear device 18 clamps further, is pressed together in the radial direction, and prevents the two lines 1, 4 from being able to be separated from one another.

Depending on the size and diameter of the lines to be connected to one another, such thrust protection devices 18 can be designed differently. Possible different dimensions are shown in FIGS. 2a-2d. In Fig. 2a a thrust protection with a small axial length I is shown, in Fig. 2d a correspondingly particularly long thrust protection. The total height h1 can also be varied, and the height at the rear end h2 can also be designed differently depending on the dimensions. The length I is typically in the range

CH 711 285 B1 of 18-30 mm, the height h1 typically in the range of 14-20 mm, and the height h2 typically in the range of 10-15 mm for conventional water pipes.

Such a push lock 18 has an inner surface 22; Inner surface because this surface faces the interior of the thrust protection device or the outer surface 7 of the insertion end of the line 4. Then there is, as an introduction aid, a beveled area 28. This serves to ensure that when the tube 4 is pushed in, when the welding bead hits the thrust protection device, the thrust protection device 18 is not simply shifted in the axial direction, but above all is also expanded radially and the welding bead 17 can slide under the thrust lock 18. This is followed by the narrow rear side 27, followed by the inclined contact surface of 18, which should then rest against the surface 14 of the inside of the connecting sleeve. The angle of inclination of the surface 23 to the axis 36 is designated by the character α in FIG. 2c. Typically, the angle of inclination α for the surface 23 is somewhat larger than the angle of inclination of the surface 14 to the axis 36.

The inclined surface 23 normally merges into a curved guide according to FIG. 25 into the front 24, which in turn is now radial. At the front lower edge, designated by the reference number 27, there is no rounding or beveling, this should be so because only so the welding bead 17 can also come into contact with the front face 24 in a really controlled manner and thus exert an exclusively axial moment on the thrust protection device 18 when an attempt is made to pull the line 4 out of the sleeve 3.

In Fig. 3 different designs of the insulating layer 29 between the two different metallic areas of the anti-shear device 18 are now shown. The insulating layer 29 separates a first metallic region 33 arranged radially on the outside from a second metallic region 34 arranged radially on the inside. In other words, the regions 33 and 34 are formed as separate circumferential metallic profiles or configured as circular ring segments. In between is the continuous layer 29, which, as already described above, is preferably formed from a plastic material filled with quartz sand, typically an epoxy resin. This layer 29 is not conductive.

Different geometric configurations of this layer 29 are shown in FIG. 3. 3a shows a stepped variant, here there is a first axially extending region 30, viewed from the rear to the front, this is followed by a conically widening obliquely extending region 31, and then merges into a second, axial region 32 is in turn offset from first region 30. An alternative to this configuration can also be designed such that region 31 runs radially and, in other words, layer 29 is designed in a step-like manner.

It is important that the two metallic areas 33 and 34 do not come into contact at any point and so the electrical conductivity between the sleeve 3 and the second pipe 4 is made impossible.

An alternative design is shown in Fig. 3b, here the entire layer is designed inclined.

A third possible variant is shown in Fig. 3c, here the layer 29 is axially aligned over the entire length I of the thrust protection. Also shown in FIG. 3 is the thickness d measured in the radial direction.

The different designs according to FIG. 3 have different advantages. In any case, it is advantageous if the corresponding plastic layer 29 is subjected to shear forces as little as possible or only to a limited extent or only in certain sections. Plastic layers are generally resistant to pressure, but less to shear forces, and variants a and b in FIG. 3, for example, are particularly advantageous in this regard.

Fig. 4 shows an axial view of a whole such a thrust lock in two different variants.

A circumferential ring is shown in FIG. 4a. In this construction, the first metallic region 33 and the second metallic region 34 are each formed as individual, separate rings, in between there is a continuous and coherent layer 29 which separates these two regions 33 and 34 in an electrically conductive and thus galvanic manner.

4b shows a variant where individual ring segments 37 of the thrust protection 18 are connected with the aid of connecting elements 38, which are typically designed to be slightly elastic for expansion during installation. For this purpose there are axially extending openings in the individual ring segments 37, into which the dumbbell-shaped elastic elements 38 are inserted. The form fit between the ring segments and the elastic elements can also be implemented differently. Such a ring can also have only 3 segments or 5 or more segments. In this case too, the individual segments 37 are each formed from two separate metallic areas 33 and 34, which are mechanically connected to one another via a coherent layer 29, but are electrically or galvanically separated.

Manufacture of a prototype and measurements:

3 shows how the metallic separation can be implemented. FIG. 5 shows a prototype that has been built, it is a construction according to FIG. 4b, and a view into the slot that would be provided for the connecting element 38 is shown. The two rings of the metallic areas 33 and 34 were in

CH 711 285 B1

Produced turning process and then glued together with epoxy resin, which fine quartz sand was mixed in, using spacers (see Fig. 4b). The adhesive surfaces were sandblasted beforehand. After the adhesive had cured, the ring was divided into 4 segments in a manner analogous to a cast iron template. Corresponding holes and slots were created for the final connection of the segments by means of the rubber elements (FIG. 4b).

Measurements:

Experimental setup of the test track: In a practical test, the new retaining ring was installed in a sleeve. The goal was to apply pressure to the two pipe sections and to expose them to mechanical forces. The test section consisted of 2 natural pipes and a socket connection from the applicant including the thrust protection according to the invention.

The structure for measuring the resistance via the socket connection with the new thrust protection consisted of two nested Natural pipes. For the measurement, brackets were welded onto both sides of the sleeve so that the metal of the pipes could be contacted with clamps. The potential difference U [mV], the compensating current I [mA] and the AC and DC resistance Rac [Ω] / R _D c [Ω] could thus be measured at these connections via the sleeve. A device of the type FLUKE 1625 was used for the resistance measurement. The voltages and compensating currents were recorded using a Fluke 87 device.

The test sequence took place in the following test steps:

1. Without water; 2. Filled with water (6 bar); 2.2. Additionally angled 3 °; 3. Filled with water (10 bar); 4. Filled with water (16 bar); 5. Filled with water (25 bar); 5.2. Additional 3 ° angled [0058] Results:

The results per test step are shown in Table 1.

Table 1: Measurement results on the examined socket connection

U [mV] I [mA] Rac [Ω] Rdc [Ω] 1. Without water 144 0.62 69.8 115.3 2. 2. Filled with water (6 bar) 40 0.48 32.7 55.8 2.2. Additionally angled 3 ° 39 0.59 26.7 49.9 Third Filled with water (10 bar) 52 1.01 26.4 31.3 4th Filled with water (16 bar) 61 1.05 19.0 27.6 5th Filled with water (25 bar) 25 0.72 18.3 26.7 5.2. Additionally angled 3 ° 52 1.02 18.4 25.6

Before filling with water, the socket connection showed a resistance of around 100 Ω, the AC resistance being relatively smaller than the DC resistance in relative terms.

With the water filling, a first pressure load and the response of the thrust protection, the resistance values of the connection halved. With increasing pressure up to 25 bar, the resistance decreased again by around half.

A potential difference as well as a compensating current could be measured between the two tubes over the entire duration of the experiment. This fact confirms the effectiveness of the galvanic isolation of the retaining ring. 6 shows the results of the AC resistance measurements.

Based on the measured values, it can thus be said that there was no metallic contact between the two pipes with the new connection. The galvanic isolation remained even under a pressure of 25 bar and an additional angling of 3 °.

The measurements show that the electrical separation effect of the new connection is not dependent on the filling, pressurization and deflection. Although the resistance values decreased with increasing pressure, no metallic conductive connection via the sleeve was found during any of the operating conditions.

The proposed new method thus ensures sustainable protection against corrosion in the case of heterogeneous bedding, stray current and galvanic corrosion with foreign cathodes.

Further improvements can be achieved via the production. It is possible to connect the electrical separation function together with the elastomer elements to connect the segments. Specifically, a circumferential elastomer ring can be provided, the insulating component being incorporated or connected directly into it. These include, for example, the covering with glass fiber fabric or the use of larger ceramic elements

CH 711 285 B1 possible. The individual elements of the retaining ring are then connected directly to the elastomer ring. This also has a function as an assembly aid.

It is also possible to make bores or cutouts on the contact surfaces between the two halves of the retaining ring, into which holes electrically insulating elements are inserted. On the one hand, these ensure the correct positioning and also the correct distance between the two halves during the connection.

A prior coating of the individual ring parts with a fusion-bonded epoxy resin ensures corrosion protection and also prevents the bridging of the two elements by metal chips. Since the surfaces are already optimally coated, the two elements can be glued together very easily. Quartz sand or glass fibers can also be added for bonding.

Reference symbol list [0068]

Pipe section with connecting sleeve

Interior of 1

Connection sleeve from 1

Pipe section with insertion end

Insertable, free end of 4

Interior of 4

Outer surface of the wall of 4

Inner surface of 1

Heel in 8 rearmost area of 3 rear chamber for elastic seal in 3, seal chamber encircling elastic seal front chamber of 3, securing chamber flaring inner flank of 13 vertical section of 13 front opening of 13 and 3 respectively

welding bead

Shear protection circumferential inward groove in 11

Extension area of 13 front end of 3

Inner surface of 18

Contact surface from 18 to connection sleeve

Front of 18 curved

Transition area from 23 to 24 narrow back of 18 front lower edge of 18, contact area for welding bead

CH 711 285 B1 chamfered area insulating layer rear axial area of 29 conically widening area of 29 front axial area of 29 metallic area of 18 for contact and contact to connection sleeve metallic area of 18 for contact and contact at insertion end

Outer wall section from insertion end with contact to 18

axis

Circular ring segment from 18

Connecting element of 18 between 37 d thickness of 29

I axial length of 18 h1 total radial height of 18 h2 height at the rear of 18 α inclination angle of 23 to the axial direction

Claims (13)

claims 1. thrust protection (18) for the connection of a first pipe section (1) with a connecting sleeve (3) with a second pipe section (4) with an insertion end (5), the insertion end (5) being inserted into the connection sleeve (3) and the Thrust protection (18) ensures a non-positive and / or positive connection between an axial section of the insertion end (5) and the connecting sleeve (3), characterized in that the thrust protection (18), which is at least designed as a circular ring segment (37), arranges a first, radially outside has a metallic area (33) which, when the first pipe section (1) and the second pipe section (4) are connected, is in frictional and / or form-fitting contact with an inner wall section (14) of the connecting sleeve (3), a second metallic area arranged radially on the inside ( 34), which, when the first pipe section (1) and the second pipe section (4) are connected, in a force-locking and / or formsc there is positive contact with an outer wall section (35) of the insertion end (5), the first metallic region (33) and the second metallic region (34) being electrically insulated from one another. 2. thrust protection (18) according to claim 1, characterized in that the electrical insulation between the first metallic region (33) and the second metallic region (34) is designed as a continuous axially extending layer (29) which the regions (33, 34) electrically separates from one another, the first metallic region (33) being arranged radially on the outside of this layer (29) and the second metallic region (34) being arranged radially on the inside of this layer (29). 3. thrust protection (18) according to claim 2, characterized in that the layer (29) is formed on the basis of a plastic material, preferably on the basis of a crosslinked or uncrosslinked polymer, which is particularly preferably mixed with one or more fillers, it being in particular preferably the polymer is a thermosetting polymer, preferably a crosslinked polymer based on phenol, bisphenol and / or aliphatic building blocks, particularly preferably in the form of an epoxy resin. 4. Shear protection (18) according to claim 3, characterized in that the fillers are glass fibers and / or particulate fillers, preferably with an average grain size d50 in the range of 0.01-0.5 mm, particularly preferably with an average Grain size d50 in the range of 0.1-0.3, with the particulate fillers preferably being selected from the following group: ground glass, broken glass, glass spheres, particulate inorganic mineral fillers, including stone powder, silicates, carbonates, oxides, hydroxides, where CH 711 285 B1 particularly preferably uses quartz sand as the particulate filler, and the proportion of filler is in the range from 2-80 percent by weight, preferably in the range from 20-70 percent by weight, particularly preferably in the range from 50-60 percent by weight. 5. thrust protection (18) according to any one of the preceding claims 2-4, characterized in that the layer (29) measured in the radial direction over the entire extent a thickness (d) of at least 0.1 mm, preferably in the range of 0, 5-4 mm. 6. thrust protection (18) according to any one of the preceding claims 2-5, characterized in that the layer (29) at least in sections axially and parallel to a main axis (36) of the thrust protection (18), the layer (29) either as a whole axially and parallel to this main axis (36), or only in one or more axial sections (30,32), and between these axial sections (30,32), which are then preferably radially offset by the free end ( 5) of the insertion end facing section (32) is arranged radially further outwards, a curved or inclined (31) layer area is arranged. 7. thrust protection (18) according to any one of the preceding claims, characterized in that it is designed in the form of a circumferential ring, in which either individual circular ring segments (37) are connected to one another via preferably elastic connecting elements (38), or in which the circumferential ring is constructed from circumferential one-piece elements (29, 33, 34). 8. thrust protection (18) according to any one of the preceding claims, characterized in that it has a radially inner, axially extending circular cylindrical inner surface (22) for non-positive and / or positive contact with the outer surface (35) of the insertion end (5), and a radially outside, conically widening contact surface (23) inclined to the axis (36) for non-positive and / or form-fitting contact with a preferably correspondingly inclined inner contact surface (14) of the connecting sleeve (3), preferably the angle of inclination of the conically expanding contact surface (23) to the axis (36) in the range of 10-45 °, particularly preferably in the range of 15-30 °. 9. thrust lock (18) according to claim 8, characterized in that the inner surface (22) is formed by the second metallic region (34) and the contact surface (23) by the first metallic region (33), preferably the first metallic region (33) and the second metallic region (34) are formed from the same material, preferably from iron or an iron alloy, particularly preferably from cast iron, from ductile cast iron or steel. 10. A method for producing a thrust protection device (18) according to one of the preceding claims, characterized in that the first and the second metallic region (33, 34) are manufactured in a first step in the form of circumferential rings or in the form of partially circumferential circular ring segments, and then the two areas are preferably connected to one another by a continuous axially extending layer (29), the layer (29) electrically separating the areas (33, 34) from one another, and the first metallic area (33) radially on the outside of this layer (29) is arranged and the second metallic region (34) is arranged radially on the inside of this layer (29). 11. The method according to claim 10, characterized in that the layer (29) is formed as part of an entire coating of at least one of the areas (33, 34) in a coating process. 12. Connection between two metal pipe sections (1,4) using a thrust protection device (18) according to one of the preceding claims 1-9, characterized in that a first pipe section (1) has a connecting sleeve (3) which has at least one radially inward has an open first chamber (13) in the form of an at least partially circumferential groove, preferably at least one further inwardly open chamber (11) in the form of a circumferential groove for receiving an elastic seal (12), and wherein the first chamber further preferably a conical has widening inner contact surface (14) which contacts the thrust lock (18) arranged in the first chamber (13) via its first region (33), and that the second pipe section (4) is inserted into the connecting sleeve with its insertion end (5) , with a portion (35) of the outer surface of the insertion end (5) contacts the thrust protection (18) over its second area (34) and preferably has a circumferential welding bead (17) on the outside (7), which is provided for the axial contacting of the thrust protection (18), preferably on its front side when viewed in the direction of insertion. 13. A method for producing a connection according to claim 12, characterized in that a circumferential welding bead (17) is provided on the outside (7), optionally after inserting an elastic seal (12), preferably in the form of a circumferential ring made of an elastic plastic material , in the connecting sleeve (3), the thrust lock (18) is placed in the first chamber, if necessary, the thrust lock (18) is widened with a mounting wedge, and then the insertion end (5) into the connecting sleeve (3) along the axis (36) is inserted until the welding bead (17) comes to rest in front of the push lock (18) in the insertion direction. CH 711 285 B1 CH 711 285 B1 [yui] ^oa l! [AUI] ^oa n