JPS62132147A - Temperature correction for decision on deterioration of wire covering - Google Patents

Abstract

PURPOSE:To always judge the degree of deterioration of wire covering accurately detecting the hardness at a reference state, by pressurizing a decision unit with pressure needle and providing a temperature sensor. CONSTITUTION:A decision unit body 1 is equipped with a pressure needle 4, a temperature sensor 8 and the like. Then, a receptacle 5 is retracted to allow a covered wire W into a broader clearance 14 between the receptacle and the pressure needle 4. Under such a condition, when an operator holds a grip section of a lever 13, the receptacle 5 advances together with a lever 13 to grasp the wire W securely between the receptacle and a mobile guide 10. The pressure needle 4 presses the wire W by a pressure force with a pressure spring 6 and the displacement thereof along the length of the pressure needle 4 is varies with the hardness of a cover body of the wire W. The current displacement is detected with a displacement sensor 7 to measure the hardness thereof. The sensor 8 also gets in contact with a cover body to measure the temperature thereof. In addition, a circuit section 2 calculates the hardness of the cover boy at a reference temperature by a computation processing from the hardness detected with a sensor 7, the temperature detected with the sensor 8 and the like and the results of the decision are displayed 3.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is a deterioration test for determining the deterioration of the covering portion of a covered wire that is mainly used outdoors, such as a lead-in telephone line made of soft vinyl chloride coated wire. The present invention relates to a temperature correction method for performing temperature correction in a determination device.

<Prior Art> When coated wires such as vinyl chloride coated wires are used outdoors for a long time, the coating material deteriorates and cracks occur, leading to insulation failure.

Therefore, a determination device has already been proposed that determines the degree of deterioration of a covered wire in use at the site of use.

The determination device holds a covered wire to be measured between a pressure needle to which a constant pressure is applied and a pedestal facing the same, and detects the hardness of the covering of the wire from the amount of displacement of the pressure needle. The device is designed to determine the degree of deterioration, and the entire device is small and portable.

<Problems to be solved by the invention> By the way, covered electric wires installed outdoors become hot due to direct sunlight and cooled due to cold air, and the deterioration state of the coated wires is the same. Even in the case of steel, it exhibits different hardness depending on the environmental temperature at the construction site. Therefore, it is not possible to determine the actual degree of deterioration of such a covered wire by simply measuring the hardness of the covering at the installation site.

The present invention has been made in view of the above-mentioned problems, and is designed to always detect hardness in a reference state and accurately determine the degree of deterioration, regardless of the environmental conditions at the construction site or measurement site. The purpose is to

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention is provided with a temperature sensor that comes into contact with the covering almost simultaneously with the application of pressure by the pressure needle in advance on the main body of the determination device, and The temperature of the sheath is calculated from the temperature measured after a certain period of time after the temperature sensor contacts the sheath, or the temperature of the sheath is actually measured by contact for the required time, and the temperature of the sheath and the hardness of the sheath at that time are calculated. A linear equation of hardness/temperature that corresponds to the rain sound and has a constant linear coefficient is searched for from This is a configuration of the temperature correction method for the determiner.

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings. FIG. 1 is a block diagram of a wire coating deterioration determiner used to implement the method of the present invention, and the determiner includes a determiner main body I, a circuit section 2, and a display section 3.

FIG. 1 shows the approximate planar shape of the determiner main body I.
As shown in the figure, the determiner main body 1 includes a pressure needle 4, a pedestal 5 facing the pressure needle 4, a pressure spring 6 that applies a constant pressure force to the pressure needle 4, and a pressure spring 6 for applying a constant pressure force to the pressure needle 4. It is equipped with a displacement sensor 7 such as a potentiometer for detecting displacement, and a temperature sensor 8 such as a thermistor is arranged in parallel at a position adjacent to the pressure needle 4. In the figure, reference numeral 9 denotes a frame of the main body L of the determination device, IO a movable guide, II a spring that supports the movable guide IO in a retractable manner, I2 a spring that supports the temperature sensor 8 in a retractable manner, and 13 a pedestal. This is a lever that supports 5.

The pedestal 5 can be moved back to the left in FIG. 1 together with the lever I3, and when in use, the coated wire to be measured is placed in the gap 4 between the pedestal 5 and the pressure needle 4, which is widened by the retreat of the pedestal 5. Insert W. In this state, the operator presses lever 1.
When the grip part (not shown) of 3 is grasped, the pedestal 5 moves to the lever 13.
move forward to the position shown by the solid line, and move the movable guide 1
The covered wire W is clamped and fixed between the wire and the wire. The pressure needle 4 is brought into pressure contact with the fixed covered wire W by a constant pressing force from the pressure spring 6, and the amount of displacement along the longitudinal direction of the pressure needle 4 is adjusted according to the hardness of the covering of the covered wire W. Change. Since the amount of displacement at that time is detected by the displacement sensor 7, the hardness of the covering body is ultimately measured by the displacement sensor 7. Further, at the same time that the pressure needle 4 comes into pressure contact with the covering, the temperature sensor 8 comes into contact with the covering, and the temperature of the covering is detected by the contact.

The circuit section 2 has built-in calculation means, storage means, power supply, etc., and performs predetermined calculation processing based on the hardness detected by the displacement sensor 7, the temperature detected by the temperature sensor 8, etc. The hardness of the coating at the reference temperature is calculated. In addition, the display section 3 displays one hardness value at the reference temperature calculated in the circuit section 2, or displays the hardness at the reference temperature of the covering that is the measurement target in the circuit section 2 and the judgment reference value. When comparing the hardness standard value, the determination result is displayed.

Now, when the inventor of the present invention repeatedly conducted experiments and measurements regarding the relationship between the hardness of the covering of the covered wire W and the temperature, it was found that the hardness and temperature have a primary relationship, and that regardless of the progress of deterioration, We found the fact that the linear coefficient in the relationship is constant.

In other words, as shown in the characteristic diagram in Figure 2, if we graph the relationship between hardness and temperature with temperature on the horizontal axis and hardness on the vertical axis, each temperature of the coating in a given state of deterioration will be The hardness value for each is a straight line S with a constant slope. , S4. ...appeared above. And these straight lines S. .

S3. The slopes of ... were all r-0.36J. In this case, the hardness of the steel wire is rlooJ.

In FIG. 2, the straight line S is shown as a solid line. indicates the hardness/temperature relationship of the coating in the reference state, and as the coating deteriorates, its hardness will show a higher value. straight line S
l is a straight line S indicating a reference state. Although it ranks higher,
The straight line S is also the straight line S in the reference state. The straight line S in the reference state has the same slope (same first-order coefficient) as . is parallel to

Therefore, in the present invention, based on the above knowledge, calculations for determining the hardness at the reference temperature are performed in the order shown in the flowchart of FIG. First, in step Nl, the temperature T1 of the covering is determined by measurement by the temperature sensor 8, and
In step N2, the hardness H in that temperature state is detected by measurement by the displacement sensor 7. Here, if the temperature T of the covering body cannot be immediately determined by measurement, as will be described later,
First, the measured temperature 'r, (t2
) may be detected and the temperature T of the covering body may be determined from this measured temperature r2(tz) by performing necessary calculations.

Then, in step N3, by applying both values of temperature T and hardness H3 to the graph, a linear equation (straight line S) corresponding to both values is obtained. The straight line of the following equation is
This is a straight line that passes through point P whose coordinates are ('r,,H,) and whose slope is r-0,36J. The straight line Sl of this - following equation and the reference temperature (specifically 20°C) T.

The point of intersection with the vertical line passing through the point is the reference temperature T of the covering to be measured. The hardness is Ha. So step N
4 is the reference temperature T. The hardness Ha at is calculated by proportional calculation. This reference temperature T. The hardness Ha at is displayed on the display section 3. The operator visually checks this hardness value Ha and compares it with the determination reference value H6 of the wire coating to determine the degree of deterioration.

Further, if the storage means in the circuit section 2 stores the judgment reference value H8 for each type of covered wire, the hardness Ha and the judgment reference value H already calculated in the circuit section 2 in step N5.
6 to determine the degree of deterioration, and in step N6, the determination result of usability/unusability is displayed on the display section 3.

By the way, according to the inventor's experiments, the temperature T of the wire sheathing is not detected immediately after the temperature sensor 8 contacts it. During the middle of the day in midsummer, the covered wire W is heated to a fairly high temperature, and on the other hand, the tester itself! The temperature of the temperature sensor 8 itself is about the outside temperature, and if there is a temperature difference between the wire sheathing W and the temperature sensor 8, the temperature sensor 8 detects the true temperature T1 of the sheathing. It takes a considerable amount of time.

FIG. 4 is a characteristic diagram showing the change over time between the temperature T of the covering body and the measured temperature T2 of the temperature sensor 8, which was obtained by measurement by the inventor of the present invention, and based on the characteristic diagram, the temperature sensor 8 is The state of change between the temperature T measured by the temperature sensor 8 and the temperature T of the covering when it comes into contact with the covering will be explained.

Suppose now that the covered wire W is at a high temperature, and the temperature sensor 8 is at a lower temperature T2(0) than this. When the temperature sensor 8 comes into contact with the covering at almost the same time as the pressure needle 4 presses (time t), the contact portion of the covering is cooled by the temperature sensor 8, and its temperature T1 temporarily decreases. do. The temperature T measured by the temperature sensor 8 gradually increases by absorbing the heat of the temperature sensor 1 and the cover. After a certain short period of time has elapsed, the cooling of the contact part of the covering body stops, and its temperature TI rises in parallel with the temperature T measured by the temperature sensor 8, and after a sufficiently long time (5 to 6 seconds) after contact, As time passes, the temperature of the contact portion returns to the temperature before contact, and the temperature sensor 8 detects the true temperature T of the covering.

If the temperature sensor 8 is kept in contact with the covering for a sufficiently long time in this way, the true temperature T of the covering can be detected even if there is a large temperature difference between the temperature sensor 8 and the covering. However, it is not preferable to continue pressurizing the pressure needle 4 and contacting the temperature sensor 8 for a sufficiently long time at the measurement site in order to proceed with the work efficiently. In particular, in the case of a type in which the main body of the analyzer is measured by the operator's grasping operation, as shown in Figure 1, it becomes necessary to avoid holding the instrument for the required period of time, which places a heavy burden on the operator. This makes it difficult to hire. When measuring by gripping, it is desirable that the measurement result be obtained within 1 to 3 seconds after gripping.

Therefore, the inventor of the present invention studied a method of estimating the true temperature TI of the covering from the temperature rt(tt) measured by the temperature sensor 8 after a certain short time (t,) of contact.

As shown in FIG. 4, the temperature of the coating before the temperature sensor 8 comes into contact with it is T, and the temperature measured by the temperature sensor 8 (which is also the temperature of the temperature sensor 8 itself) is 'rt(o),
After a certain short time of contact, the later measured temperature is 'r t(tt)
Assuming that, the temperature difference between the covering body and the temperature sensor 8 is ΔT
11 If the temperature change at the time of contact with temperature sensor 8 is 8T, then ΔT,=TI-72(0)...
...(a)ΔT 2-T t(tt)-'r t(0)
......(b), T, -ΔT, 1Δ'r 2(o)...
...(c). Here, temperature difference ΔT, = α × Δ
Assuming T, T,=α×Δrt+'rt(o)...
...(d).

If it is possible to calculate TI by substituting a specific value for the temperature coefficient α, assuming that α is a constant temperature coefficient, then the true value of the covering body can be calculated from the measured temperature T1 (11) at t after a certain short time of contact. Therefore, it is possible to estimate the temperature T1 of .

Therefore, the inventor investigated the relationship between the time t2 after contact, the temperature coefficient α, and the temperature change ΔT of the temperature sensor 8 after contact. The result is the characteristic diagram shown in FIG.

As is clear from the figure, regardless of the magnitude of the temperature difference ΔT between the covering and the temperature sensor 8, the time t after contact,
After 1.5 seconds, the range of change in the temperature coefficient α becomes narrower, and thereafter, as the time t after contact becomes longer, the temperature coefficient α converges to a constant value.

As described above, if the determination device body 1 is of the type in which measurement is performed by an operator's gripping operation, it is not possible to take a long time after contact. If the time t after contact is set to 1.8 seconds, the temperature coefficient α takes a value between "4" and "7". In the region where the temperature difference ΔT1 is small, the temperature coefficient α
Since the error caused in the coating temperature difference T due to the difference in the value of is small, the error will be reduced overall if the temperature coefficient α is adjusted to a region where the temperature difference ΔT+ is large. Therefore, here, the temperature coefficient α is set according to the region where the temperature difference ΔT1 is large.
is set to "4".

Under these settings, as shown by the dotted line in the flowchart of FIG. 3, first, in step M+, the temperature sensor 8 The measured temperature 'rp(tt) of is detected. The values obtained up to this point are the measured temperature 'r, (tz
) and the temperature before contact 'r, (o).

The temperature change ΔT is obtained from both temperature measurements. This temperature change ΔT is multiplied by the temperature coefficient α (=4), and the sum (sometimes subtracted, in which case the difference) of the product plus the temperature 'r, (o) before contact is the coating temperature. T, and by these calculations, the temperature T1 of the covering body is determined in step M2.

By setting the temperature coefficient α in this way, the true temperature T1 of the covering can be calculated from the change ΔT in the measured temperature after a certain short time (b = 1.8 seconds) after contact with the temperature sensor 8. can do.

From this coating temperature T and the hardness HI at that time, a linear equation corresponding to both is obtained by following the steps from step N3 in the flowchart of FIG. 3, and from this equation, the reference temperature T is calculated. A hardness Ha is obtained.

In the above example, the temperature coefficient α was fixed at a constant value and the coating temperature T1 was calculated using the temperature coefficient α, but if we look at it strictly, it can also be seen from the characteristic diagram in Figure 5. As such, the temperature coefficient α increases or decreases depending on the temperature difference ΔT between the covering body, the temperature, and the sensor 8.

If the temperature difference ΔT+ between the covering and the temperature sensor 8 is large,
Since the change T2 in the temperature measured by the temperature sensor 8 after contact is also large, the temperature coefficient α may be increased or decreased depending on the magnitude of the change ΔT in the measured temperature after contact. In other words, considering the temperature coefficient α as a function of the temperature change ΔT2, α=F(ΔT2)...
(E) may also be used.

By changing the value of the temperature coefficient α according to the magnitude of the temperature change ΔT in this manner, a more accurate covering temperature T1 can be obtained, and thereby temperature correction can be performed accurately.

<Effects of the Invention> As described above, the method of the present invention utilizes the knowledge obtained through experiments by the inventor that the temperature and hardness of a covered wire have a linear relationship with a certain coefficient. Therefore, by calculation based on this knowledge, it is possible to calculate the hardness at the reference temperature from the temperature and hardness of the sheathing at the time of measurement, and the degree of deterioration of the sheathing can be accurately determined regardless of the environmental conditions at the measurement site. can do.

Furthermore, by estimating the temperature of the sheath by multiplying the change in temperature measured after a certain period of time after contact with the temperature sensor by the experimentally determined temperature coefficient, it does not take much time to measure the temperature of the sheath. Judgment results can be obtained in an extremely short period of time, and operations can be carried out efficiently without placing any burden on the operator.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a wire coating deterioration determination device used to carry out the method of the present invention, Fig. 2 is a characteristic diagram showing the relationship between the temperature and hardness of the covered wire, and Fig. 3 shows the determination operation according to the method of the present invention. The flowchart, FIG. 4 is a characteristic diagram showing the change over time between the covering body temperature and the measured temperature, and FIG. 5 is a characteristic diagram showing the change over time in the temperature coefficient in each temperature difference region. l... Judgment unit body, 2... Circuit section, 3... Display section, 4... Pressure needle, 5... pedestal, 7... Displacement sensor, 8... Temperature sensor, T1... Covering temperature, 'r
2(0),'r z(tt)...Measurement temperature of the temperature sensor, ΔT,...Temperature difference between the covering and the temperature sensor, ΔT
,...Change in measured temperature.

Claims (2)

[Claims] (1) A covered wire to be measured is held between a pressure needle to which a constant pressure is applied and a pedestal facing it, and the hardness of the wire's coating is detected from the amount of displacement of the pressure needle, and its deterioration is detected. This is a temperature correction method for a wire coating deterioration determination device that determines the degree of deterioration of a wire. The temperature of the sheath can be calculated from the temperature measured after a certain period of time after contacting the sheath, or the temperature of the sheath is actually measured by contacting the sheath for the required time, and the temperature of the sheath and the hardness of the sheath at that time are calculated. A wire coating deterioration determination device, characterized in that it searches for a linear expression of hardness/temperature that corresponds to and has a constant linear coefficient, and calculates the hardness of the coating at a reference temperature from the linear expression of hardness/temperature. Temperature correction method. (2) When calculating the covering temperature, multiply the change in temperature measured by the temperature sensor after a certain period of time has passed after contact by a certain temperature coefficient, and then add the temperature measured by the temperature sensor before contact to the product. 2. A temperature correction method for a wire coating deterioration determiner according to claim 1, which performs an operation of adding and subtracting and using the sum or difference as the coating temperature.