JPS5913808B2 - Method and device for manufacturing filled electrical cables - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for measuring the filling efficiency of the filling process in the manufacture of waterproof cables. The capacitances are measured and 6 these capacitances are compared.

Telecommunications cables, especially those buried underground,
It is desirable to have a moisture-proof structure to prevent moisture from penetrating the cable.

Generally, such moisture resistance is achieved by filling the cable with a suitable filler, such as mineral oil or a mixture of mineral oil and polyethylene, during manufacture of the cable. For good results, the filling material should be 6
All space within the cable not occupied by conductors etc. shall be filled. Various methods and devices for filling cables are known, 6 for example U.S. Pat.
No. 2215, No. 3854444, No. 3850139, No. 3789099, No. 3876487 and No. 37
No. 33225. In conventional filling techniques, the filler material is applied after the cable core is formed and before the final binder and cover are applied.

At this point in production. Although it is difficult to inject the filler compound into the cable core because it is packed in a relatively small size, it is necessary to fill the filler space uniformly and without any gaps in order to prevent moisture from entering during later use. must be done. Various methods have been devised to determine the amount or proportion of filler that has entered the cable, which indicates the efficiency of the filling process.

One method is to cut off the end of the finished cable V). This applies water pressure to one end of the cut cable piece. If more than a predetermined amount of water flows out of the other end of a cable piece, the cable is considered defective.
Another method is to weigh the cable segment, since the weight of the unfilled space is known and the correct amount of fill material to be filled is known. must be at least the sum of these two weights. Another method to determine the quality of a filled cable is to measure the capacitance between multiple pairs of conductors on the outer part of the cable and then measure the capacitance between multiple pairs of conductors on the inner part. 6 and then compare these measurements. An index representing the filling efficiency is obtained by dividing the difference between the two measurements by the measurement of the outer conductor pair. By comparing this with an experimentally determined quantity, it is possible to determine whether the cable is valid.

Prior art methods for determining filling efficiency, such as the example given above, involve testing completed cables. Therefore, if it was discovered that the filling efficiency was inadequate, the entire cable could be scrapped or it would be necessary to attempt refilling. Also,
When measuring or testing a short length of cable, there is no way to determine whether the rest of the cable is the same as the test piece, and the test result is also at risk. On the other hand, even when testing the entire cable using the capacitance measurement described above, cable failures are often due to defects in very short sections, so if you know the location, you can cut them out. It can also be removed. This last drawback is a problem common to all prior art techniques, and there is no way to determine where in the cable the filling is less than the allowable value.

Another disadvantage of the prior art is that all tests are performed on finished cables, which means that defective cables must be scrapped or refilled.
In either case, extra time and expense were required. The above problems are solved by the process of continuously monitoring the capacitance changes of the outer conductor pairs while the six cables pass through the filling chamber according to the present invention. The process of continuously monitoring the capacitance changes of the inner conductor pair while the cable passes through the filling chamber, and comparing the monitored capacitance changes of the outer conductor pair and the inner conductor pair with each other during filling. The present invention is solved by a method and apparatus that includes the steps of ascertaining the filling efficiency of an operation and providing an indication of the location along the length of the cable of the point or area where the variation in filling efficiency has occurred.

Through the above process, the location of cable defects caused by a decrease in filling efficiency during the filling operation can be clearly pointed out.

The filling efficiency here is simply the ratio of the filled volume to the fillable volume, and in terms of cross-sectional area.
It is the ratio of the cross-sectional area that is actually filled to the cross-sectional area that can be filled. By implementing the above process and continuously monitoring changes in capacitance, the present invention can be used to control the filling operation to maintain the filling efficiency within acceptable limits during manufacturing. It is possible.

That is, the method of the present invention also includes the step of changing filling operation parameters in response to variations in filling efficiency to correct for the variations. One of these parameters is. pressure and temperature of the filling compound. Includes the speed of cable movement during the filling process. In Figure 1. A cable core 1 is shown wound around a shaft 14 on a rotatable pull-out reel 2. The wick 1 is shown passing through a filling chamber generally designated by the number 3. The core 1 advances from the filling chamber 3 through a total of 4 lengths in the direction of 6 take-up reels. The take-up reel is driven by 6 suitable drive means 10, not shown.
Between the filling chamber 3 and the length 4, 6 binders are wrapped around the core, and an aluminum cover is placed over the binders. In addition, various processes are performed in which the insulating jacket covers the cover, but these are all processes well known to those skilled in the art of communication cables.
Not shown here. In the embodiments shown in FIGS. 1 and 2. The cable core 1 includes a plurality of twisted wire pairs of insulated conductors 6.

It is connected via an outer twisted pair lead 8 consisting of a conductor 7 to a capacitance measuring circuit, an encoder and a transmitter. These are generally designated by block 9 and are shown in detail in FIGS. 3 and 4. The circuit of block 9 is connected to input coupling coil 12 via output lead 11.
This coil rotates together with the reel 2. The input coupling coil 12 is connected to the output coupling coil 13 fixed on the shaft 14.
is combined with The coil 13 is connected via a lead 16. It is connected to the receiver and decoder shown in block 17. These details are shown in FIG. Similarly, the inner twisted wire pair (FIG. 2), consisting of 6 insulated conductors 18, is connected via 61 pairs of leads 19 to the inputs of the capacitance measuring circuit 6 encoder and transmitter.

These are indicated by block 21 and the details are similar to block 9 of FIGS. 3 and 4. The circuitry of block 21 is connected to coupling coil 12 by output lead 22. The signal from lead 22 is coupled from coil 12 to stationary coil 13, which is further connected via lead 23 to a receiver indicated by block 24. receiver 24
is similar to block 17 shown in FIG. Furthermore, the outputs of the six receivers 17 and 24 are . It is connected to a computer that can use a general-purpose computer, that is, a processor 26,
I will discuss its purpose in detail later.

The capacitance monitoring circuitry contained within blocks 9 and 17 and shown in FIGS. 3 and 4 provides a highly accurate monitoring function.

Other circuits for monitoring capacitance changes may also be used depending on their accuracy and speed of response. In the following description, blocks 9 and 171C for measuring changes in capacitance between conductors 7 will be described, but blocks 21 and 24 for measuring changes in capacitance between 6 conductors 18 are also substantially the same circuits. be. Since coils 12 and 13 are commonly used for the two monitoring systems, blocks 21 and 24 are connected to block 9.
and 17 in that they use a different frequency. As the filling process progresses, the mutual capacitance between the six pairs of conductors 7 increases.

This is because air has a dielectric constant of 1.0. For example, dielectric constant 2
．． This is because it is replaced by a filling compound having 2. moreover. As the length of the filled portion of the cable core increases, the capacity increases as a function of this length. The monitoring device. It operates under the assumption that under normal process conditions the outer conductor pair 7 is filled with approximately 100% filling compound. This is because this conductor pair is outside the cable core 1 when passing through the filling chamber 3. Third
In the figure, a reference voltage source 31 generates a DC voltage of 6, eg, positive 5 volts, which is applied via a lead 32 to an inverting amplifier 34 and one contact 42 of a transfer switch 39.

The output of amplifier 34 is applied via lead 37 to another contact 38 of switch 39. The switch 39 can take various forms and can be realized, for example, as a solid state component. The voltage applied to contacts 42 and 38 is 33, respectively, in FIG.
and 36. Switch 39 applies a positive 33 or negative 36 reference voltage to buffer amplifier 46 via lead 44. As will be described later, by periodically operating switch 39, a waveform such as 45 in FIG. 5 can be generated on lead 44 and output lead 47 of amplifier 46. The output of the amplifier 46 is a differential amplifier (
A constant current generator) 48 is applied to its negative input, and its output is applied to a conductor 7 via a charging resistor, thereby charging (or discharging) the inter-conductor capacitance. Because amplifier 48 provides a small amount of gain relative to the reference input voltage, the interconductor capacitance is higher than the positive or negative reference voltage, respectively. Or charging pressure is low. The buffer amplifier 51 charges (and discharges) the capacitance.
will be monitored. Amplifier 51 serves to isolate the capacitive charging circuit from the loading effects of other parts of the circuit. The output of amplifier 51 is shown as waveform 55 in FIG. 5, and is applied via lead 66 to the summing or positive input of amplifier 48. As a result. Amplifier 48 monitors the difference between its two voltage inputs and supplies a constant current through resistor 49 to charge or discharge the capacitance of conductor 7. The output of amplifier 51 is also applied via lead 52 to a voltage divider consisting of resistors 53 and 54. The output of this divider is shown by curve 59 in FIG.
and 58 are applied to one input of each. Comparators 57 and 58 have positive and negative reference voltages applied to their other inputs via leads 41 and 37, respectively. Furthermore, the output of amplifier 51, shown by curve 55 in FIG. 5, is also connected to one input of each of six comparators 63 and 64, with the other inputs of these comparators . Positive and negative reference voltages are applied via leads 41 and 37, respectively. The outputs of comparators 57 and 58 are applied to flip-flop 61, the output of which is used to control switch 39.

The input waveform to the comparator 57 (59 in FIG. 5) is the lead 41.
When equal to or greater than the positive reference voltage above, comparator 57 generates an output to set flip-flop 61 so that contact 43 of switch 39 is connected to contact 38. Therefore, a negative reference voltage is applied to amplifier 46. Conversely, if the input waveform (59 in FIG. 5) is equal to or more negative than the input from lead 37 to comparator 58. Comparator 58 generates an output to reverse flip-flop 61 and toggle the switch so that a positive reference voltage is applied to amplifier 46. Through this operation, a waveform 45 shown in FIG. 5 is generated and applied to the amplifier 48. The circuit described above monitors the capacitance of the conductor 7 until the charge on the conductor 7 reaches a specified reference value.

The capacitor is then discharged and recharged six times to a reference value of reverse polarity. The length of charge and discharge cycles should be monitored to also assess capacity changes. This applies to comparators 63 and 64 in the circuits of FIGS. 3 and 4.
This is performed by a circuit associated with this. As mentioned above, the output of the buffer amplifier 51 follows the charging and discharging of the capacitance of the 6 conductor pairs 7, and its waveform 6 becomes like the waveform 55 in FIG.

This output is applied to comparators 63 and 64. Comparator 6
The outputs of 3 and 64 are applied to two inputs of a NOR gate 67. When no signal is applied to either of the two inputs of NOR gate 67, gate 67 produces a true or on signal at its output, but when a signal is present at either input, the output is turned off. If the signal applied from amplifier 51 to comparator 63 is smaller than the signal on lead 41, comparator 63
produces no output signal. Similarly, if the signal from amplifier 51 to comparator 64 is greater than the signal on lead 37, comparator 64 will not produce an output. When these two conditions are met, NOR gate 67 generates an on signal. However, if the input from amplifier 51 to comparator 63 is equal to or greater than the signal on lead 41, comparator 63 will produce an output. The Noah gate 67 is thereby turned off. Similarly,
When the signal from amplifier 51 to comparator 64 is less than or equal to the signal on lead 37, comparator 64 produces an output and NOR gate 67 is turned off. Come on. When waveform 55 of FIG. 5 is applied to comparators 63 and 64, the output of 6-NOR gate 67 becomes waveform 68 of FIG. 5, and the length of the charging cycle is represented by the on time T in the figure. When the cable is filled. Because the capacitance increases, the period T
increases, and as a result, the slopes of waveforms 55 and 59 become gentler. In FIG. 4, the output of 6-NOR gate 67 is applied to one input of AND gate 69, and gate 6
A clock signal from a crystal oscillator clock 70 is applied to the other input of 9. The output of gate 69 is applied to binary counter 71. Time T of waveform 68 in FIG.
}, that is, when the NOR gate 67 is producing a true or on output, a series of digital pulses having the clock frequency are applied to the counter 71.
A binary number counted by 1 and representing the length of time T is output to shift register 72. The timing control circuit 73 is
A signal from flip-flop 61 is received via lead 65, and each time the state of flip-flop 61 changes, counter 71 is reset and shift register 7 is reset.
2 is sent out serially to the digit divider 74.

Therefore, the counting cycle of the counter 71 is . This is done in conjunction with the monitored capacitance charging and discharging cycles. Furthermore, the 6 actual counts represent the length of the charge and discharge cycles, which change (increase) as the filling process progresses. Digit divider 74 also receives input from clock 70 as well as the contents of shift register 72 and produces 61 pairs of output frequencies.

For example, this frequency is 6.25kHz and 5.68kHz.
, one of which is the binary ``1'' from shift register 72
” and the other represents the binary “O”. The output of divider 74 is sent from low pass filter 76 to coupling coil 12 .
This becomes a signal representing the capacitance of the conductor 7. At this stage of operation in the monitoring system shown in FIG. 1, an audio frequency signal will be generated indicative of the capacitance of the conductor 7 during the filling process.

Similarly, a signal indicating the capacitance of the six conductors 18 is produced by the circuit of the transmitter 21. There are many ways in which comparisons can be made to these signals to determine fill effectiveness. Fourth
The remaining circuitry in the figure shows one configuration approach for doing this. The audio frequency signal of coil 12 is detected by coil 13 and applied from lead 16 to bandpass filter JMOV.

Filter R7 passes only the capacitance of conductor 7 and frequencies representing changes in capacitance. A similar filter in receiver 24 passes only those frequencies indicative of the capacitance and capacitance changes of conductor 18. The signal from filter JMoV has a frequency (6.25kHz
z or 5.68 kHz) to a transducer 78 which generates a voltage output with an amplitude according to the frequency.

The output of this converter is applied to a voltage comparator 79, converted into a 1-bit 62-decimal number, and applied to a shift register 81.

Comparator 79 and shift register 81 will continuously receive asynchronous serial data from the transmitter. Comparator 79
The output of is also applied to the synchronous logic circuit 831fC.

Circuit 83 detects the time when a complete data word is entered into shift register 81 and simultaneously signals data holding circuit 82 connected to register 81 to store the data word. The holding circuit 82 then reads the read command signal 85.
Then, the computer 26 receives the signal from the holding circuit 82 from the lead 86 and stores it.
The binary data read into computer 26 from lead 86 relates to the capacitance between conductors 7. The length meter 4 in FIG. 1 also receives a signal from the calculator 26 from a lead 88. Similarly, data regarding the capacitance between conductors 18 is also applied to computer 26 from lead 87. The signal applied from the length meter 4 to the calculator 26 is a pulse generated per certain length b, for example, one pulse is applied per foot of the cable 1. The operation of the calculation steps performed by calculator 26 is best understood by the flow diagram of FIG.

As previously mentioned, the signals applied to the coil 12 and the signals from the length meter form the data necessary to calculate the filling efficiency of the filling process. The circuitry of receiver 17 in FIG. 4 is designed so that this data is used by computer 26. However, it is clear that the operations described below can be performed using a device other than a computer if necessary. Block 91 in FIG. 6 shows data input to computer 26.

The computer then determines the cable length for each of the outer twisted wire pair 7 and the inner twisted wire pair 18 by dividing the capacitance change by the change in cable run length, as shown in block 92 of FIG. Calculate the increment or slope of capacitance per unit length of . The calculator 26 then compares the slope of the capacitance of the outer conductor thus obtained with a predetermined slope value 6 and, if there is a difference, calculates the percent value of the difference.

The predetermined slope value is equivalent to 1km in length! It is based on a cable with an average mutual capacitance of 252 nanofarads. This step is illustrated at block 93 in FIG. The calculator 26 performs the same calculation for the inner conductor pair 18, but in this case calculates the percentage difference from the capacitance slope of the outer conductor pair 7.

This is shown at block 94 in FIG. The computer then calculates the filling efficiency for the outer twisted wire pair 7, as shown in block 96 of FIG.

The charging efficiency is determined by the mutual capacitance difference and is a function of two main variables.

The first variable to consider is the mutual interaction of the 62 insulated conductors 7. and the physical spacing relative to other insulated conductors 6 within the cable. The second variable is the conductor. It is the dielectric constant of the insulating material filled between conductors. However, from a practical point of view, the physical spacing variables can be assumed to be nearly constant during the cable filling process6.
It can be regarded as a constant in calculations.

Therefore, it is necessary to consider only the dielectric constant of the insulating material covering the six conductors. Calculations must be made in the form of mutual capacitance. As mentioned above, the filling efficiency is expressed by the ratio of the cross-sectional area filled with the waterproofing compound to the cross-sectional area where 100% filling is possible.

Furthermore, it is a function of the ratio of the part filled with the compound to the total cross-sectional area or the dielectric constant of the total cross-sectional area.

Therefore, the filling efficiency can be determined by the following formula.

Filling efficiency: where EF = permittivity of the fillable area of the cable EPJ = permittivity of the pure filler compound. By measuring the change in this permittivity, the amount of filler compound added can be determined. .

However, since this change cannot be measured directly, an equation must be used that describes the above change for the total change in measurable mutual capacitance.

This is given by the following equation. EFmax = Maximum value of E for 100% filling EFmin = 1.00 in air E = Overall permittivity EI = Dielectric constant of conductor and insulator Mutual capacitance without filling R = When filling 100% By substituting the equation for the mutual capacitance EF into the above equation, we can solve for the filling efficiency.

However, if we look only at a specific cable, the first equation can be simplified.

For example, in testing during manufacture of a polypropylene insulated cable with a mutual capacitance of 52 nanofurads per Kn1, the equation becomes: Here, ΔE = difference between the capacitance of the outer conductor and a predetermined value. or the difference in the capacitance of the inner and outer conductors (block 93 or 94 in FIG. 6). In the example cable above, the ΔE(7)01) value is limited to the range O-16.

All of the above calculations are shown as occurring in blocks 96 and 103 of FIG.

The derivation of the equation described above is as follows. The overall relative dielectric constant E of the composite is given by:
E=EIVI+EFVF・・・・・・・・・・・・・・・
・ (1) Here, EF is the relative permittivity of the filling EI is the relative permittivity of the insulator of the conductor VI is the relative volume of the insulator F is the relative volume of the filling Generally E, VI and VF is unknown.

E may be measured for 100% filling rather than no filling. EF is 100 instead of unfilled.
(:fl) is known for filling. E1 is known. Therefore, VF and VI can be determined by substituting the known EI and EF.

That is, EFmax=EFEF at 100% filling
min = EF without filling Also, VI = 1 - F Now solving equation (1) for EF, its derivative is: 1 ≦ where the cable as a function of the % difference in relative permittivity of the composite. The percent change in relative dielectric constant of the filled region is obtained.

Now the relative filling efficiency (RFE) as a function of %ΔEF
), use the following formula.

That is, by using equation (2) and substituting 6 EFmax=2.22 into equation (3), it is simplified as follows.

FIG. 7 shows the filling efficiency equation as a function of the percentage difference in mutual capacitance for the example cable described above.

As mentioned above, it is assumed that the outer stranded conductor 7 is normally 100% filled.

If this filling is actually performed when the gradient is calculated in block 93 of FIG. 6, the calculated filling efficiency in block 96 will be the maximum of 100%. However, if the above-described filling is not performed, the filling efficiency will be that calculated at block 96 of FIG. If this value is less than a predetermined value, the calculator 26 sends a signal to the lead 98 in FIG. Attempts are made to satisfy predetermined filling conditions. This operation is illustrated in block 101 of FIG. Valve 99 is a Model 6 manufactured by Digital Dynamics of Sunnyvale, California.
A digital flow valve such as the 607D can be used. Additionally, computer 26 issues a signal to lead pair 102 of FIG. 1 to increase the temperature of filling chamber 3 and reduce the stickiness of the filling compound.

The computer 26 can also output a signal from the lead 110 to control the driving means 10 to change the speed at which the cable 1 is advanced. Obviously the computer continuously monitors the filling efficiency of one of the above variables. Or a combination;
Or you can control everything.

Calculator 26 also calculates the filling efficiency of inner twisted wire pair 18 using the above equation as shown in block 103 of FIG. The calculated value may be different from the value calculated for the outer twisted wire pair 7 (block 96 in FIG. 6). This is because the slopes are different (
(See blocks 93 and 94 in FIG. 6). When the calculated value is less than the predetermined required value as determined by block 104, the calculator 26 returns to the clock 10 of FIG.
A signal is generated to control the variable as shown in 6.

These signals are similar to the signals generated in block 101 of FIG. 6 and indicate the pressure or temperature of the froth-filling compound. or 6 to control the speed of cable 1. During operation of the device, computer 26 sends a signal to lead 107 and records the results of continuous monitoring of filling efficiency in recording device 108.

This record can be made by printing the numerical value directly for each corresponding length of the filled cable core or by using the blocks 96 and 10 in Figure 6.
This plots the data calculated in step 3 and the cable length. Although the accuracy is lower than the above method, the conductor 18
Filling efficiency can also be obtained by measuring only the change in capacitance of a pair of stranded conductors close to the center of the cable, such as .

A signal indicating such a capacity is processed in the same manner as described above and entered into the computer 26. Calculator 26 contains standard capacitance change values for a particular cable and processes the measured change values through blocks 93, 96, 97, 101 and 108 of FIG. To summarize the above, 1. In a method for measuring the filling rate of a filling operation in the manufacture of waterproof cables containing multiple conductors, changes in the capacitance of the outer conductor pair are continuously monitored as the cable passes through a filling chamber. , continuously monitor the change in capacitance of the inner conductor pair as the cable passes through the filling chamber, and compare the capacitance changes of the outer and inner conductor pairs with each other to determine the performance of the filling operation. and a step of checking the filling efficiency.

2. The method in paragraph 1 above fails. moreover. A step is included for providing an indication as to the location along the length of the cable that is causing the change in filling efficiency.

3. The method of item 1 above further includes the step of comparing Vc and the monitored capacitance change of the outer conductor pair with a predetermined reference value.

4 In addition to the method in item 1 above. The process includes generating control signals to vary parameters of the filling operation in response to variations in fill efficiency to maintain the variations within an acceptable range.

5. In the method of paragraph 4 above, the pressure of the filler material is varied to keep the variation within the acceptable range.

6. In the method of paragraph 4 above, the temperature of the filler material is varied to keep the fluctuations within the acceptable range.

7 In accordance with the method of item 4 above, 6 the control signal increases the speed at which the cable passes through the filling chamber by Fbl.

8. A method for monitoring the amount of fill introduced into a cable during its passage through a filling chamber, comprising: a step for monitoring changes in capacitance of torsion conductor pairs within the cable; and 6.
comparing the monitored capacitance change to a predetermined standard capacitance change value.

9. A first means for continuously measuring changes in capacitance of an outer pair of conductors as the cable passes through a filling chamber, using an apparatus for measuring filling efficiency in the manufacture of waterproof cables containing a plurality of conductors; A second step that continuously measures the change in capacitance of the inner conductor pair as the cable passes through the filling chamber.
means. and means associated with the first and second means for generating a signal indicating a change in capacitance when the capacitance changes.

IO In the apparatus of paragraph 9 above, 6 means are included for determining filling efficiency, including means for comparing the capacitance change of the outer conductor pair with the capacitance change of the inner conductor pair.

11 In addition to the apparatus of paragraph 10 above, 6 the comparing means generates a control signal in response to variations in the filling efficiency and 6 changes parameters of the filling operation to maintain the variations within an acceptable range. Contains the means for

A device for measuring the filling efficiency of the filling process in the manufacture of waterproof cables containing two or more conductors is used to continuously charge and discharge the capacity of a pair of conductors between the upper and lower voltage limits. means including a voltage source; comparison means for generating a signal for reversing the voltage applied to the capacitor in response to the charge on the capacitor reaching a charging limit; a second comparison means for indicating that the charge of the capacitance exceeds upper and lower voltage limits; means for generating a pulse train in the absence of the indication from the second comparison means; and means for generating a pulse train in the absence of the indication from the second comparison means; means for counting the pulses produced during the charging and for indicating by the counts the charging and discharging times of the capacitor.

13 In the apparatus of item 12 above. Further, means for continuously charging and discharging the capacitance of the second pair of conductors between upper and lower limits of six voltages; third comparison means for responsively reversing the voltage applied to the capacitance, and a fourth comparison for indicating that the charge on the capacitance of the second conductor pair has exceeded upper and lower voltage limits. means for generating a second pulse train when there is no indication from the fourth comparison means. and means for counting the pulses produced during the display and indicating by the counts the charging and discharging times of the capacitance of the second conductor pair.

14 In the apparatus of item 13 above, 6 further includes means for converting the pulse into a signal indicative of the capacitance of the outer conductor pair and the inner conductor pair, and a means for converting the signal indicative of the capacitance of the outer conductor pair. compared to the signal indicating the capacitance of the inner conductor pair.
and means for determining the filling efficiency of the filling process.

15. In the apparatus of paragraph 14 above, the means for determining includes means for generating control signals to vary the parameters of the filling process to maintain the filling efficiency within an acceptable range.

16. In accordance with the apparatus of paragraph 14 above, the means for determining includes means for generating an indication indicating the variation in fill efficiency.

17 In the apparatus of item 16 above. Means are included for monitoring the run of the cable through the filling chamber to indicate where along the cable length variations in filling efficiency occur.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a part of the cable core, filling device, length meter, and monitoring device, and FIG. 2 is a diagram showing a block diagram of the monitoring device and the connection to the cable core. )6 3rd
The figure is a capacitance measurement circuit diagram. Figure 4 is a diagram of the encoder circuit, transmitter, and receiver/decoder circuit used in the present invention, Figure 5 is a diagram of waveforms appearing at various points in the above measurement circuit, and Figure 6 is a diagram realized by the present invention. This is a flowchart of the computer used. and FIG. 7 is a diagram showing a graph of filling efficiency for a particular type of cable. [Description of main parts of drawings] Terms used in claims Code Cable...16 Filling chamber...3
, outer conductor pair...76 inner conductor pair...
...18, First means...9,17, Second means...21,246 Means for generating a signal...
...266 Charging and discharging means ...48,
Comparison means...57, 58, second comparison means...
...63,64,Means for generating pulse train・
...69,70. Means for representing charging and discharging times...71.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a filled electrical cable that includes a plurality of outer and inner stranded conductor pairs and is waterproofed in the longitudinal direction, the unit length of the outer and inner conductor pairs being waterproofed in the longitudinal direction. A method for manufacturing a filled electrical cable, which includes the steps of: measuring the capacitance per unit; and determining the filling efficiency of the electrical cable using calculations from the measurement process, Continuously during the filling operation; continuously determining the change in capacitance of each of said measured conductor pairs relative to the reference signal; percentage difference in capacitance of the outer conductor pair with respect to the reference value; calculate the percentage difference in capacitance of the inner conductor pair to the percentage difference in capacitance of the outer conductor pair; calculate the percentage difference in capacitance of the outer conductor pair and the inner conductor pair from the two calculated percentage differences; continuously and separately determine the filling efficiency of the pair; in response to the difference between the determined filling efficiency value and the value of the reference signal, the pressure and temperature of the filling material, or the forward speed of the cable, etc. A method for producing a filled electrical cable, characterized in that it forms a control signal that changes in the direction of adjusting or more filling parameters. 2. first means for continuously measuring the change in capacitance of the outer conductor pair within the cable as the cable passes through the filling chamber; a second means for continuously measuring a change in capacitance of the inner pair of conductors; related to the first and second means, measuring the change when the capacitance of the conductor changes; means for generating a signal indicative of the filling efficiency; and means for comparing the capacitance change of the outer conductor pair with the capacitance change of the inner conductor pair to determine the filling efficiency; In response to the difference between the value of the reference signal and the value of the reference signal, parameters related to the filling operation such as the pressure and temperature of the filling material, the forward speed of the cable, etc. An apparatus for manufacturing a filled electrical cable, characterized in that the comparing means includes control signal generating means for maintaining the temperature of the filled electrical cable.