DE8628900U1 - Tracking cable - Google Patents

Description

Tracking cable.

The invention relates to a coaxial cable with an internal conductor as the cable core and an insulation layer surrounding the conductor in a ring shape with inserts to form a protective layer against moisture and mechanical damage.

Supply lines for gas, water and waste disposal lines are usually laid underground. Often, the position or course of a line must be determined during new installations, when determining damage or when planning construction work. For lines made of metallic materials and for cables, well-known locating methods are used. However, these locating methods use the metallic lines or one of the cable cores for locating.

In the pipe networks used today, house connections for gas, water and waste disposal lines, non-metallic materials such as plastic, asbestos cement or clay are often used. With lines made of these materials, it is difficult to locate the position and depth, as the methods and means known for locating metal lines and cables cannot be used. It is therefore the object of the present invention to develop a coaxial cable of the type mentioned at the beginning.

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so that it can be used as a locating cable for locating non-metallic lines.

To solve this problem, it is proposed to provide in accordance with the invention that, in order to form a locating cable for a non-metallic pipeline, a layer of an approximately rigid plastic with fiber reinforcement is arranged around the conductor.

Using such a coaxial cable, which has a conductive structure at its core, it is possible to locate non-metallic pipes by position and depth. The coaxial cable is used in conjunction with a well-known audio frequency locating device, consisting of an audio frequency transmitter and an audio frequency receiver.

Preferred embodiments of the invention are characterized in the subclaims.

An embodiment of the invention is explained in more detail below with reference to the drawing.

Fig. 1 'a coaxial cable in a vertical sectional view,

Fig. 2 shows a locating device with a locating cable in its arrangement in and around a line to be located in a schematic representation,

F 1 g. 3 the function of the locating cable in a locating device in a schematic representation, F i g. 4 the relationship between the position of the receiver coil, the position of the conductor of the coaxial cable and the intensity of the received tone in a schematic representation, and

Fig. 5 Examples of arrangement of the search coil holder in relation to the conductor of the locating cable in a schematic representation.

The coaxial cable shown in cross-section in Fig. 1 consists of a conductor 10 which is surrounded by an insulating layer 11, on which a further layer 12 is arranged, which consists of a plastic with a fiber reinforcement 12a made of carbon fibers or glass fibers. A further protective layer 13 made of a suitable plastic is laid over this layer. The entire coaxial cable 20 has this structure between its ends 21, 22.

The use of such a coaxial cable 20, which contains the electrically conductive conductor 10, enables the location of non-metallic pipes 50 according to position and depth. When handling the coaxial cable 20 in conjunction with an audio frequency locating device 30, 40 as shown in Fig. 2, the procedure is such that the coaxial cable 20 is pushed as far as possible into the open end 51 of the non-conductive pipe 50.

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so that one end 21 of the coaxial cable 20 is as far away as possible or at the other end of the tube 50. When inserting the coaxial cable 20 into the tube 50, the smallest bending radius of the largely rigid coaxial cable must be observed. After inserting the coaxial

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connected via an insulated cable to the other end 22 of the coaxial cable 20, which is usually arranged on a reel 23. At the same time, the audio frequency transmitter 30 is connected to the auxiliary earth 31. The auxiliary earth 31 should be about 5 m away from the detection route.

Preferably, the roller 23 is arranged on insulating feet 24 in order to prevent premature discharge of the audio frequency current.

The location can be carried out after coupling (— 10 kHz) and power adjustment of the audio frequency transmitter. The galvanic coupling to the audio frequency transmitter generates a partially capacitive current which forms an alternating field around the conductor 10 of the coaxial cable 20 through which it flows, as shown in Fig. 3.

The actual location can then be carried out using the maximum method for a rough determination of the position and the minimum method for a precise determination of the position of the pipeline, as shown schematically in Fig. 4. The coil 45 of the audio frequency

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receiver 40 in the coil holder 46 is initially arranged parallel to the horizontal, which results in the intensity distribution indicated in the drawing. Then the coil 45 is arranged vertically, so that by determining the minimum intensity of the audio frequency, the position of the conductor 10 and thus the position of the pipeline (not shown in this figure) can be precisely determined.

By using a right-angled, isosceles triangle, the laying depth can be easily determined. By adjusting the coil holder 46 so that the coil is at an angle of 45° to the horizontal, the distance (A, B) corresponds to the laying depth (T). This locating method for finding non-metallic pipes can be used in the supply sector as well as in civil engineering and when searching for sewage pipes.

The coaxial cable that has now been created is particularly suitable for carrying out this process, or rather, it creates the possibility for carrying out the process for the first time, since the additional layer 12 with the fiber reinforcement 12a offers the possibility of inserting the coaxial cable into a pipeline, whereby when the cable is guided, it follows the pipeline path. The use of fiber reinforcement also prevents the cable from becoming fatigued, whereby the outer

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Protective layer 13 prevents mechanical or chemical damage from outside.

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Claims (4)

DI PL.-I NQ. J. RICHTER PATENT ATTORNEYS DIPL.-ING. F. WERDERMANN SELECTED REPRESENTATIVES AT THE EPO · PROFESSIONAL· REPRESENTATIVES BEFORE EPO ■ MANDATAIRES AGREES PRES LOEB SOOO HAMBURG 36 / 29.10.1986 NEUER WALL 1O 9 (O 4O) 340045/340056 TELESRAMMER: INVENTIUS HAMBURG TELEX 2163 551 INTU D OUR FILE S . 864O8~III"4568 Applicant; Hans-Jürgen Sültmann, 2050 Hamburg 80 Ortunqs cable. protection claims; 1. Coaxial cable with an inner conductor as the cable core and an insulation layer surrounding the conductor in a ring shape with inserts to form a protective layer against moisture and mechanical damage, characterized in that a layer (12) made of an almost rigid plastic with a fiber reinforcement (12a) is arranged around the conductor (10) to form a locating cable for a non-metallic pipeline. [ti* 'j &iacgr;&ogr; ill ))] 2. Coaxial cable according to claim 1, characterized in that the fiber reinforcement (12a) consists of glass fiber mats or carbon fibers. 3. Coaxial cable according to claim 1 or 2, characterized in that an insulating layer (11) made of PVC or polyethylene is arranged between the conductor (10) and the layer (12). 4. Coaxial cable according to one of claims 1 to 3, characterized in that a protective layer (13) made of a suitable plastic, preferably a thermosetting plastic, is arranged annularly surrounding the layer (12). ix-