Induction cable, coupling device, and method for producing an induction cable

Abstract

An induction cable contains a plurality of cable conductors each having a conductor strand surrounded by insulation. The conductor strand contains a plurality of conductor sections which are spaced apart in the longitudinal cable direction at resonance dividing points by insulating intermediate pieces. The induction cable furthermore has a coupling device on which a plurality of the conductor strands are separated forming coupling ends at coupling positions. The coupling ends are connected to each other via the coupling device. A simple providing and installing of the induction cable and a simple replacement of damaged cable parts is thus enabled.

Claims

1. An induction cable, comprising: a plurality of cable cores each having a conductor strand being surrounded by insulation and said conductor strand having a plurality of conductor sections which are respectively spaced apart at an insulating intermediate region by at least one insulating intermediate piece at resonance separation points in a cable longitudinal direction, said conductor strands having coupling ends at a coupling position; a coupling device having two coupling parts and a coupling module having receptacles for said coupling ends of said conductor strands and disposed at the coupling position; said coupling device is disposed at a resonance separation point, and said receptacles of said coupling module including a plurality of first receptacles for a first connection type and for accommodating first coupling ends of said coupling ends, wherein in each case said at least one insulating intermediate piece is situated in each of said first receptacles; the induction cable further satisfying one of the following two conditions: a) the induction cable is subdivided at the coupling position so as to form two cable ends, and said two coupling parts of said coupling device combining said cable ends, said receptacles of said coupling module include a plurality of second receptacles for a second connection type and for accommodating second coupling ends of said coupling ends, wherein two said coupling ends are electrically conductively connected to one another in each of said second receptacles; or b) only some of said conductor strands are connected by said coupling device and some of said conductor strands are continuous at the coupling position without interruption wherein said coupling module has a number of recesses formed therein for a passage of said conductor strands which are continuous at the coupling position.

2. The induction cable according to claim 1, wherein said coupling ends can be reversibly connected to one another by means of said coupling device.

3. The induction cable according to claim 1, wherein said coupling ends are held in said coupling device by means of plug connections and, to this end, plug connection elements are selectively formed at said coupling ends or in that said coupling ends are plugged into said receptacles of said coupling module.

4. The induction cable according to claim 1, further comprising sleeves disposed in said receptacles, said coupling ends being introduced into said sleeves and said sleeves are selectively formed from an insulating material or a conductive material.

5. The induction cable according to claim 4, wherein said sleeves each selectively have an at least partially profiled inner wall, or said coupling ends are provided with a profiled portion.

6. The induction cable according to claim 4, further comprising a termination piece fitted onto each of said coupling ends.

7. The induction cable according to claim 1, wherein said coupling module has a star-shaped carrier on which said receptacles are formed, wherein said star-shaped carrier having arms in which the first receptacles in a form of passage holes are formed and wherein said recesses, which are formed for the passage of said conductor strands which are continuous at the coupling position, are open radially and are formed between said arms.

8. The induction cable according to claim 1, wherein said coupling module is an injection-molded part.

9. The induction cable according to claim 1, further comprising a functional line selected from the group consisting of a strain-relief device, a sensor line and a data line, said functional line is guided through said coupling device without interruption or so as to form two partial pieces which are connected to one another.

10. The induction cable according to claim 1, wherein said coupling ends have a connection direction which is not parallel to the longitudinal direction but which is at a prespecified angle in relation to the longitudinal direction.

11. The induction cable according to claim 1, further comprising a sensor module integrated in said coupling device.

12. The induction cable according to claim 4, wherein said insulating material is a ceramic.

13. A method for producing an induction cable, which comprises the steps of: connecting coupling ends of a plurality of cable cores to one another with an aid of a coupling device, the coupling device having two coupling parts and a coupling module with receptacles for coupling ends of a plurality of conductor strands of the cable cores and disposed at a coupling position, the coupling device is disposed at a resonance separation point, and the receptacles of the coupling module including a plurality of first receptacles for a first connection type and for accommodating first coupling ends of the coupling ends, the coupling device having in each case at least one insulating intermediate piece disposed in each of the first receptacles; the induction cable further satisfying one of the following two conditions: a) the induction cable is subdivided at the coupling position so as to form two cable ends, and the two coupling parts of the coupling device combining the cable ends, and the receptacles of the coupling module have a plurality of second receptacles for a second connection type and for accommodating second coupling ends of the coupling ends, wherein two of the coupling ends are electrically conductively connected to one another in each of the second receptacles; or b) only some of the conductor strands are connected by the coupling device and some of the conductor strands are continuous at the coupling position without interruption wherein the coupling module having a number of recesses formed therein for a passage of the conductor strands which are continuous at the coupling position.

14. The method according to claim 13, which further comprises: connecting two cable ends to one another by means of the coupling device, in such a way that the cable ends are rotated relative to one another about a cable longitudinal direction, disposing sleeves disposed in the receptacles, the coupling ends being introduced into the sleeves and the sleeves are selectively formed from an insulating material or a conductive material; introducing each of the first coupling ends into a sleeve; fitting a plug connector element to each of the second coupling ends, namely a plug pin on one side and a plug sleeve on the other side; fitting a termination cap onto the end side of a respective first coupling end and a free space between the termination cap and the sleeve is filled with a further insulation material.

15. The method according to claim 13, wherein conductor sections are provided as individual lengths and are connected by means of the coupling device so as to form resonance separation points.

16. The induction cable according to claim 4, wherein: each of the first coupling ends is introduced into a sleeve being an insulating sleeve; and a plug connector element is fitted to each of the second coupling ends, namely a plug pin on one side and a plug sleeve on the other side.

17. The induction cable according to claim 16 wherein a termination cap is fitted onto said end side of the respective first coupling end and a free space between the termination cap and the sleeve is filled with a further insulation material.

18. The induction cable according to claim 10, wherein the conductor strands are running helically and having a pitch, wherein the connection direction of the receptacles corresponds to the pitch.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a symbolic, side view of an induction cable according to the invention;

(2) FIG. 2 is a cross-sectional view of the induction cable having a plurality of component cables;

(3) FIG. 3 is a cross-sectional view of a component cable;

(4) FIG. 4 is a plan view of a carrier, which is configured as a separator star, of a coupling module;

(5) FIG. 5 is a cross-sectional view of a further variant embodiment of the carrier of a coupling module;

(6) FIG. 6 is a schematic cross-sectional view of the coupling device having two coupling parts;

(7) FIG. 7 is an illustration of a detail of a further exemplary embodiment of a coupling module; and

(8) FIG. 8 is a highly simplified schematic illustration of receptacles, which are oriented in a connection direction, having conductor strands.

DETAILED DESCRIPTION OF THE INVENTION

(9) In the figures, similarly acting parts are provided with the same reference symbols.

(10) Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown an induction cable 1 extending in a cable longitudinal direction 2 and has, in the exemplary embodiment, a plurality of coupling devices 3 at which individual partial cable pieces 4 are coupled to one another. The induction cable 1 usually has a large number of cable cores 6. In this case, each individual cable core 6 is formed by a plurality of conductor sections 8 which are spaced apart from one another in the cable longitudinal direction 2 by insulating intermediate pieces 10. The conductor sections 8 together with the insulating intermediate pieces 10 form a conductor strand 9 which is sheathed by an insulation 11 (compare, in particular, FIG. 6 in this respect) in order to form the cable core 6. The insulation 11 is selectively a taping or else an, in particular extruded, insulation sheath. The intermediate pieces 10 are composed of a suitable insulation material, in particular of ceramic.

(11) In this case, the conductor sections 8 have a contact spacing a typically in the region of several tens of meters, for example in the region of 50 m or a multiple thereof. The overall length of an induction cable 1 of this kind is usually several hundreds of meters, in particular in the region of a few kilometers, for example in the range of from 1 to 3 km. Induction cables 1 of this kind are laid in the ground in order to inductively heat oil sands. The induction cables are usually introduced into pipes for this purpose. The coupling devices 3 are at a distance of greater than the contact spacing a, in particular a multiple of the contact spacing a, in relation to one another.

(12) At the same time, the intermediate pieces 10 define resonance separation points R which are arranged in the contact spacing a. The resonance separation points R of the various cable cores 6 are located at different longitudinal positions, wherein a plurality of the cable cores 6 are preferably combined to form groups, of which the resonance separation points R are located at an identical longitudinal position. In the exemplary embodiment, two groups of cable cores 6 are formed, the resonance separation points R of the groups being offset in relation to one another by half a contact spacing a.

(13) In contrast, a respective coupling device 3 defines a coupling position K at which, therefore, a plurality of cable cores 6 are interrupted and connected by the coupling device 3. Here, interrupted is intended to be understood to mean that the cable core 6 or the conductor strand 9 is not guided further without interruption, but rather is separated so as to form coupling ends 20a, b (compare, for example, FIGS. 3 and 6 in this respect). The individual cable cores 6 typically have a diameter in the range of from, for example, 1.5 to 2.5 mm, wherein the conductor strand 9 has a diameter of typically 0.8 to 1.5 mm.

(14) A preferred construction of an induction cable 1 of this kind is illustrated in FIG. 2. According to FIG. 2, the overall induction cable 1 is made up of a plurality of component cables 12, wherein each component cable 12 in turn has a plurality of core bundles 14 which each have a strain-relief device 16 in the center. The individual core bundles 14 are a composite, in particular a braided composite, of a plurality of cable cores 6 which, in turn, are arranged around a central strand, in particular an optical waveguide 15. In the exemplary embodiment, the core bundles 14 are braided in two layers around the optical waveguide 15. Overall, six of these core bundles 14 are then arranged, in particular braided, around the strain-relief device 16 of the component cable 12 and form the component cable 12. The component cable 12 preferably has a cable sheath 18. The three component cables 12 are, in turn, usually braided with one another and likewise surrounded by a further cable sheath 18.

(15) FIG. 3 shows a cross section through one of the component cables 12 with the core bundle 14 braided around the strain-relief device 16. In each of the core bundles 14, the individual cable cores 16 are arranged, in particular braided, around the central optical waveguide 15. In this case, FIG. 3 shows a section through the induction cable 1 at one of the resonance separation points R. The dark circles mark first coupling ends 20a in the region of the resonance separation point R, that is to say in the region of the insulating intermediate pieces 10, whereas the light circles show second coupling ends 20b of the conductor sections 8 which are of continuous design or are then electrically contact-connected to one another by the coupling device 3.

(16) FIG. 4 illustrates a first variant embodiment of a coupling module 22 which is designed as a separator star. The coupling module contains an approximately star-shaped carrier 24 which has, corresponding to the positions of the first coupling ends 20a, first receptacles 26a in the form of passage holes which form first connections. The carrier 24 therefore has arms in which these first receptacles 26a are made in the manner of passage bores. Recesses 28, which are open radially to the outside, are formed between these arms. The continuous conductor sections 8 which are guided without interruption are inserted into these recesses 28 from the outside. In contrast, the first receptacles 26a define the resonance separation point R with the insulating intermediate piece 10.

(17) Furthermore, a functional connection 30 is formed centrally in the carrier 24, the functional connection being configured to guide and, in particular, to connect a central functional conductor, specifically the optical waveguide 15. This functional connection 30 is configured, for example, in the manner of a plug connector for connecting two light guide ends or receives corresponding plug connection elements.

(18) Whereas only a limited number of cable cores 6 are interrupted in the case of the separator star according to FIG. 4, all of the cable cores 6 of the core bundle 14 are interrupted and connected to one another by the coupling module 22 in the case of coupling module 22, as is illustrated in FIG. 5. In FIG. 5, the dark circles once again indicate the first coupling ends 20a of the electrically conductively guided conductor sections 8 and the light circles once again indicate the second coupling ends 20b at the resonance separation point R. In this respect, FIG. 5 therefore shows a cable end 32 within the meaning of the present application. Here, the light circles at the same time also define second receptacles 26b in which the coupling ends 20b are situated. These second receptacles 26b are, in turn, formed by bushings through the carrier 24. The carrier 24 is generally composed of an insulating material, in particular plastic, and is configured, for example, in an approximately plate-like or disk-like manner with only a small thickness in the cable longitudinal direction 2.

(19) In the present case, cable is generally intended to be understood to mean any common composite of cable cores 6, in particular a braided composite. Therefore, the core bundle 14 forms a smallest cable unit. The next largest medium cable unit is formed by the component cable 12, and the next largest cable unit in turn is finally formed by the entire induction cable 2.

(20) The different refinements of the coupling device 3 described here selectively relate to the smallest cable unit (core bundle 14), the medium cable unit (component cable 12) or the overall cable unit (inductor cable 2). The described construction of the coupling device 3 therefore serves selectively to connect the core bundle 14, the component cable 12 or else the entire induction cable 1.

(21) A dedicated coupling device 3 is expediently provided for each component cable 12, so that each component cable 12 can be independently separated. As an alternative, an overall coupling device 3 is also provided, it being possible for the induction cable 1 to be separated overall at a separation point by the overall coupling device.

(22) A special variant embodiment of the coupling device 3 is illustrated in FIG. 6. According to FIG. 6, the coupling device 3 has two coupling parts 34a, 34b which each receive a carrier 24 and comprise housing parts 36a, 36b which can be connected to one another to form the coupling and therefore hold the carrier 24 and therefore also the individual coupling ends 20a, 20b in a defined relative position in relation to one another. The housing parts 36a, 36b are configured, in a manner not illustrated in detail here, as plug parts or else as parts which can be screwed, for example, so that the two coupling parts 34a, 34b are therefore fastened to one another by screw-connection in the manner of screw couplings or, for example, by latching, and the carriers 24 are offset in relation to one another.

(23) In order to form the insulating intermediate pieces 10, insulating sleeves 38, in particular ceramic sleeves into which the first coupling ends 20a are introduced, are formed in the exemplary embodiment. In the exemplary embodiment, a termination cap 40, in particular which is composed of metal, is fitted, for example by welding, onto the end side of a respective coupling end. In addition, the free space between the cap 40 and the sleeve 38 is filled with a further insulation material, in particular a silicone gel 42 or else an adhesive. This provides good insulation of the first coupling ends 20a in relation to one another and achieves a high degree of resistance to partial discharge. In contrast to this, plug connector elements are fitted in the case of the coupling ends 20b of the conductor sections 8, specifically a plug pin 44 on one side and a plug sleeve 46 on the other side. The plug connector elements serve to electrically conductively connect the second coupling ends 20b. The plug connector elements are electrically conductively connected, for example by welding or else by a crimping process, to the respective second coupling end 20b. The electrically conductive connection is automatically formed when the two coupling parts 34a, 34b are combined.

(24) In the exemplary embodiment described in relation to FIG. 6, the intermediate piece 10 is configured in a manner divided into two in as much as two insulating sleeves 38 are each fitted to the first coupling ends 20a. There may further be an air gap between these sleeves 38 in the coupled state.

(25) FIG. 7 illustrates an alternative refinement of a sleeve 38, in which a double sleeve, in particular a ceramic sleeve, is situated in a respective first receptacle 26a of the carrier 22, it being possible for the coupling ends 20a to be plugged into said double sleeve from both sides.

(26) Finally, FIG. 8 shows a highly simplified illustration of another particular variant embodiment in which the receptacles 26a, 26b are oriented in a connection direction 50 at an angle in relation to the longitudinal direction 2. In this case, the angle corresponds, in particular, to a pitch angle of the individual cable cores 6 which the individual cable cores assume as a result of being braided with one another. This ensures that the cable cores 6 are in alignment with the connections 26a, 26b, so that a simple plug-in operation is possible.

(27) Particularly in the case of this variant embodiment, it is possible to also use a flat cable to form the induction cable 1, in the case of the flat cable the individual conductor strands 9 each initially being arranged within a common plane in a common insulation sheath, and this ribbon cable then being wound around a central strand. Accordingly, it is also possible to provide a coupling device 3 for a ribbon cable of this kind which may be bent, the individual connections 26a, 26b being lined up next to one another in one row in the case of said coupling device.

(28) Furthermore, a sensor module 52 is integrated into the coupling device 3, both the induction cable 1 itself and also the environment, that is to say characteristic data about the induction field for example, being monitored by the sensor module and corresponding measurement data being passed on to an evaluation unit, not illustrated in any detail here. Parameters to be monitored are, for example, the cable temperature, the ambient temperature or else seismic movements etc.

(29) The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: 1 Induction cable 2 Cable longitudinal direction 3 Coupling device 4 Partial cable piece 6 Cable core 8 Conductor section 9 Conductor strand 10 Intermediate piece 11 Insulation 12 Component cable 14 Core bundle 15 Optical waveguide 16 Strain-relief means 18 Cable sheath 20a, b Coupling end 22 Coupling module 24 Carrier 26a First connections 26b Second connections 28 Recess 30 Functional connection 32 Cable end 34a, b Coupling part 36a, b Housing parts 38 Insulating sleeve 40 Cap 42 Silicone gel 44 Plug pin 46 Plug sleeve 50 Connection direction 52 Sensor module a Contact spacing R Resonance separation point K Coupling position