DE2545470C2 - Centering an electrical conductor in an insulating sleeve - Google Patents

Description

The invention relates to a method according to claim 1 of the main patent.

The main patent deals with the task of automatically closing an electrical conductor in an insulating sheath center so that the conductor is evenly surrounded over its entire length by the insulating sleeve and this, As with plastic high-voltage cables, the same electrical resistance to applied voltages is everywhere having.

The present invention is based on the object of a further improvement of the method and to achieve the arrangement according to the main patent.

The solution is achieved through the features of the

2i claim 1. An advantageous development of this The method is characterized in claim 2. Beneficial Arrangements for carrying out these processes are given in claims 3 to 10.

The advantages of the invention are particularly therein too

in see that in addition to the eccentricity of the conductor, the outer diameter of the cable and the position of the conductor in its insulating sheath can be measured without contact in the immediate vicinity of the extruder. Pendulum movements of the cable and water droplets

> i on the cable cannot influence the measurement result according to the invention. Another important advantage is that the arrangement calibrates itself.

An execution example! der. "- r ^r indung is in the

■ * "drawings shown.

Fig. 1 shows the measuring arrangement in a schematic representation. Fig. 2 contains a block diagram the pulse evaluators 10 and 11. F i g. 3 is the illustration of a cable core in a parallel line grid

■ * '< can be found. 4 shows a cable section with a drop of water and the line grid. F i g. 5 illustrates the evaluation of a video signal with imperfections caused e.g. B. by water droplets on the edge of the cable core.

In Fig. 1 is the arrangement used to carry out the method according to the invention schematically shown. The conductor 1, which is provided with an insulating jacket in the extruder 2, passes through the cross-linking of the Insulation of the cable 3 serving, under steam pressure

> 5 vertical CV tube 45. The CV tube 45 is equipped with a Sight glass unit 19 is provided, in which the measurements are made. As with the procedure According to the main patent, the cable core 3 of two perpendicular to each other, of the light sources

w) 6 and 7 outgoing radiation beams x-rayed. The beams are received by radiation receivers 8 and 9, where the cable core to be measured is on a Target, e.g. B. a silicon multi-diode vidicon, is imaged and scanned by an electron beam.

t> 5 The electron beam is generated in cameras 8 and 9 Line grid parallel to the wire contour.

3 shows the cable core 3 to be imaged Line grid. The amplitudes of the individual lines

reach their maximum values at the points where the rays of the radiation source do not yet hit the insulating hell (left of A and right of D), while they practically come to zero where the rays are completely shielded by the conductor from the grid (between B and C). The eccentricity of the conductor is determined by counting the lines between A and B and between C and D and by calculating the quotient of the values determined. The resulting image signals are evaluated in the pulse evaluators 10 and 11 and compared with the setpoint values in the comparators 12 and 13. If the values determined from the image signals deviate from the nominal values, the extruder drives 4 and 5 are influenced in such a way that the error in the extruder 2 is corrected.

Based on this method already described in the main patent, according to the present Invention incorrect measurements due to spatially limited interferences on the cable circumference avoided will.

If there is a disturbance on the cable core shown, such as a water droplet 44 (FIG. 4), it also causes disturbances in the video signal and in the raster 42 of lines a to / "appearing in the area 43 to be mapped Fig. 5 shows in curve 3a the effect of such interference points on the pulse sequence, where these points lead to sudden changes in brightness I, II and III in the image contents of the relevant lines b, c and d prevent, a threshold value signal 3b is generated in the video signal evaluator 24 (FIG. 2) after a threshold value formation from the video signal shown in curve 3a. By means of a retriggerable monostable multivibrator connected downstream of the threshold value switch, the output pulse duration of the voltage curve 3c is determined by the last trigger pulse T. Actual the time constant of the monostable multivibrator greater than or equal to τ-Mi (r = period of Line sync pulses, / ι is the time from the end of the line sync pulse to the end of the image blanking), interference points are hidden. The signal voltage shown in curve 3c can only jump back from its positive value to zero if the image content of at least one complete line was previously black.

The measuring arrangement according to the invention is constructed in such a way that it sees itself automatically. It is in the fig. 2 in a block diagram, which provides more information about the structure of the pulse evaluator 10 and 11 there. For the sake of simplicity, only those connected to the camera 9 are shown here Facilities described. The devices connected to the camera 8 are identical to these.

The image recorded by the camera 9 is fed to the video signal evaluator 24, which is controlled by the Quartz time base 40, which specifies all the frequencies required for the measuring arrangement, is controlled. From the In the video signal evaluator 24, the signal goes through the error subtraction stage 27, on the one hand, to measure the eccentricity 28 and to the display device 20 for the eccentricity, on the other hand via a device 30 for Measurement of the position of the conductor in the insulating sleeve and to the position indicator 3). The lamps 31 show the Deviations of the conductor from the center to the right or left. From the device 28 for eccentricity measurement and 30 for position measurement, the signal goes to Mcßwcrtkompurator 39. where it comes with the setpoint

is compared. The measured value comparator39 corresponds to the comparator 12 in Figure 1. The nominal value for the eccentricity of the conductor is fixed. He is Zero. If there is a deviation of the actual value from the setpoint value, it is displayed in the device 38

To determine the diameter, the video signal goes from the evaluator 24 to the diameter evaluator 25, which is connected to the display device 26 for the diameter. The diameter evaluator 25 in turn is also connected to the Meßwertkoinparator 39, where the actual diameter with the by means of the digital switch 20 input target diameter is compared. Deviations will be back displayed at device 38.

During the measurement, the same image appears almost continuously on the storage layer of the vidicon Pictured The picture is as in fig. 3 shows very high contrast. There is black in the center of the image because there is no light due to the conductor or the conductor smoothing the storage layer falls. Outside egg · .. * Adenandes falls the light from the light source directly onto -ias target. It there is therefore a risk that the image will be burned into the storage layer of the vidicon, which leads to Can lead to incorrect measurements. In such cases, the measuring instrument can suddenly change the Do not determine the wire diameter.

In order to avoid such incorrect measurements, in the arrangement according to the invention, monitoring and Self-dumping facilities provided.

Thus, at regular time intervals, a cable simulation 32 is inserted into the beam path instead of the cable 3 of the camera 9 and imaged on the target with the aid of the illumination source 6a. Again For the sake of simplicity, only the measuring and measuring device according to the invention following the camera 9 Calibration device described. The device 11 connected to the camera 8 is identical to this.

The control of the lighting sources 6 U: '; d 6a takes place by means of the device 23. As with the measurement of the cable data, the calibration simulation of the Kabuls mapped and electron-optically scanned. The video signal is in the evaluator 24 with respect to Diameter data and the eccentricity of the conductor are evaluated. The measured actual calibration values for diameter and eccentricity are compared in the calibration value comparator 37 with the corresponding setpoint values. The target value of the eccentricity is fixed in the arrangement. The calibration diameter is for example entered by means of a digital switch 33. If the actual calibration values deviate from the target values to a certain extent, which goes beyond a predetermined threshold value, the deviation is determined by means of the device 36 deliberately. Regardless of this, any deviation of the actual values from the setpoint values in the calibration board 34 processed. The difference is shown with the ad 35 reported. Error signals are stored and are used to correct the video signal at the next Measuring process. Here, the correction signals in the error subtraction stage 27 for the measured values considered :. In this way, the values measured on the cable are affected by errors in the measuring arrangement adjusted, which are caused by aging of the components or instabilities.

Deviations of the actual value of the conductor eccentricity from the nominal value are recorded via a digital printer control 21 given to a digital printer. In addition, these values can of course also be used directly Control of the extruder drives 4 and 5 are used

that via the connection 22 with the crfindungsgemcn Plant are connected.

In addition, the terminals 22 can also use the Data of the conductor cross-centericity indicated in Fig. 29, the length of the pipe and the diameter of the cable with a Digital printer.

For this purpose 2 sheets of drawings

Claims (3)

Patent claims: 1. Method for centering an electrical conductor in an insulating sheath, in which the insulating sheath X-rayed and the conductor and the insulating sleeve constantly on the target of an image pickup tube (e.g. Vidikon), the image with a Electron beam is scanned and converted into a train of pulses, the pulses on both sides of the symmetry axis of the conductor pattern counted separately and from both numbers of the The quotient is formed, whereupon control pulses are derived if the quotient deviates from one and for bringing about the central position of the conductor within the insulating sheath to an actuating device of the extruder, according to patent P 2402480.4, characterized in that the pulse evaluation device (10, II) in predetermined time intervals by comparing the one brought into the beam path Calibration cable replica (32) automatically calibrated the measurement pulses received with predetermined setpoints and that of spatially limited defects on the insulating sleeve caused disturbances in Video signal can be faded out by forming a threshold value signal from the video signal, which is in turn converted to a positive output signal, which only then goes back to zero, if at least one complete line of the image on the target, as scanned by the electron beam is dark. 2. The method according to claim 1, characterized in that from the Videc "ügnal with the help of the Pulse evaluation device (Ii /, 11) the outer diameter of the insulating sleeve is also determined. 3. Arrangement for performing the method according to claim 1 or 2, characterized in that that a short distance behind an extruder (2) two mutually perpendicular planes erected radiation sources (6, 7) with their receivers (8, 9) depicting the cable core are provided are that the extruder (2) is driven by two servomotors (4, 5) located in these levels can be centered and the servomotors (4, 5) can be controlled by the control values obtained in the receivers are and that for the image blanking signals obtained in receivers (8, 9) pulse evaluators (10,11) are provided, which via comparators (12, 13) for the setpoint and actual values with the servomotors in Connected are that each pulse evaluator (10 or 11) a self-calibration device and a Elimination device for eliminating defects on the cable circumference due to spatially limited defects Incorrect measurements resulting from the fact that the self-calibration device is made up of one in the Beam path of the receiver (8 or 9) fade-in calibration standard (32), a video signal evaluator (24), devices (28 or 30) for determining the actual values of the eccentricity and the position of the conductor, a comparator (37) for comparing calibration actual and target values, a calibration board (34) for processing and storage of the deviations determined by the calibration value comparator (37) up to the beginning of the the measuring process following the calibration process and one in the measuring circuit between the video signal evaluators (24) and the devices (28 or 30) for determining the actual values of the eccentricity and the Position and the measured value comparator (39) connected to the calibration board (34) downstream of the error subtraction stage (27) and that the elimination device consists essentially of a retriggerable monostable multivibrator in the video signal evaluator (24).