JP2572246Y2 - Water leak detection device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water leakage detecting device used for performing a water leakage inspection of a watertight cable.

[0002]

2. Description of the Related Art Watertight cables such as CV cables laid outdoors are filled with a watertight compound between conductors and between a conductor and an insulator to prevent water running. In the manufacture of such a cable, one end of the cable is cut out and used as a sample to perform a water leakage test. FIG. 2 shows a schematic diagram of a conventional apparatus for water leakage test. In the figure, a water tank 1 is filled with water 2 and a cable 3 is connected to the water tank 1.
Is fixed so as to penetrate through a seal 4 at a bottom portion of the base. In the cable 3, the conductor 5 has a stranded structure. The gap between the conductor 5 and the insulator of the cable 3 is filled with a watertight compound (not shown). Therefore, the cable 3
When a water pressure is applied to one end of the water, if the water pressure is within a certain range, the water 2 should have a watertight property enough to prevent the water 2 from leaking outside.

[0003] In order to test the cable 3, settings as shown in the figure are performed, and a saucer 6 is arranged below the conductor 5 exposed on the outside of the cable 3, and sulfuric acid 7 is stored therein. A thermocouple 8 is attached to the bottom of the tray 6, and the thermocouple 8 is connected to a temperature recorder 9. When the temperature recorder 9 is operated in the above-described state, if water leaks from the cable 3, the water 2 flows to the receiving tray 6 and generates sulfuric acid 7. As a result, the output of the thermocouple 8 changes, and the change is recorded by the temperature recorder 9.
Many thermocouples are connected to the temperature recorder 9 from the same device, and these temperature changes are recorded on the recording paper 10. This makes it possible to conduct a water leak test on many cable terminals at once.

[0004]

However, the above-described conventional water leakage detection device requires care in handling because it uses a chemical such as sulfuric acid which generates heat. If the amount of water leakage is extremely small, it takes time to generate heat,
There is also a problem that the test time is lengthened due to a delay in detection of water leakage. Further, there is a problem that the temperature and humidity of the atmosphere are easily affected. This invention has been made in view of the above, the prior art likewise can be simultaneously used for simple and multiple leakage inspection, further providing a leak detection device with enhanced shortened sensitivity time for leak detection The purpose is to do so.

[0005]

Means for Solving the Problems The present devised the plurality of samples
Apply water pressure to each end of the cable, and
In a water leak detection device that detects the presence or absence of water leakage from the end,
Conductor exposed at each other end of each sample cable is used as a hygroscopic member
To cover each conductor and the hygroscopic member on it.
A pair of electrodes are connected respectively, and a connection is made between each pair of electrodes.
Set the multiple variable resistors to different resistance values, and
Connect both ends of these variable resistors in parallel to the temperature recorder, and
Of the reference output voltage of each variable resistor by the temperature recorder
Are recorded in parallel as temperature changes.

[0006]

When a predetermined voltage is applied between each pair of electrodes, each variable
Since the resistors have different resistance values, the voltage at both ends of each variable resistor
Input to the temperature recorder as different reference output voltages.
Is forced. On the other hand, each hygroscopic member is
When water is absorbed by leaking water, the voltage between each pair of electrodes
Since the air resistance decreases, the reference output voltage of each variable resistor also changes.
Become Therefore, the temperature recorder measures the change of each reference output voltage.
Convert to temperature change and record.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 is a schematic view showing an embodiment of a water leakage detection device according to the present invention. In the figure, it is assumed that one end of a cable 3 to be subjected to a water leakage test is exposed from the tank 1 as described above with reference to FIG. A hygroscopic member 11 made of gauze or the like is wound around the conductor 5 exposed at the end of the cable 3. Further, an electrode plate 12 made of lead or the like is wound around the outer periphery of the hygroscopic member 11. And this electrode plate 12
One end of an electrode 13A made of bare copper wire is bound to the other end, and the other end is connected to a terminal 10A of the monitoring unit 10. One end of the other electrode 13 </ b> B is bound to the conductor 5, and the other end is connected to the terminal 10 </ b> B of the monitoring unit 10.

The monitoring unit 10 is a device for measuring the electric resistance between the electrodes 13A and 13B. This monitoring unit 1
At 0, a power supply 14, a resistor 15, a variable resistor 16 and a temperature recorder 17 are provided. The power supply 14 and the resistor 15 are connected in series to the terminal 10A, and the resistor 15 and the terminal 10B
A variable resistor 16 is inserted between the two. Variable resistor 1
6 is measured by a temperature recorder 17, and the result is recorded on a recording sheet 18.
As described above, in the device of the present invention, the electric resistance between the electrodes 13A and 13B is reduced by absorbing the water leaked into the gap between the conductors 5 by the hygroscopic member 11. Therefore, the electrodes 13A, 13
By comparing the electrical resistance between B and the subsequent change in electrical resistance, it can be determined whether or not water has leaked to the conductor 5. The operation principle of the monitoring unit 10 will be described with reference to FIG.

FIG. 3 shows an equivalent circuit of the monitoring unit 10.
In the figure, the voltage of the power supply 14 is E1, the resistance of the resistor 15 is R1, the resistance of the variable resistor 16 is R2, the terminals 10A and 10A.
Assuming that the resistance between B is R3, the voltage E0 input to the temperature recorder 17 can be obtained by an equation as shown in the figure.
That is, the value obtained by dividing R2 by the sum of the resistances R1, R2 and R3 and E1
To obtain the voltage E0. Therefore, electrode 1
If the electric resistance R3 between 3A and 13B changes, the input voltage E0 of the temperature recorder 17 also changes and can be detected.

FIG. 4 shows an embodiment in which, for example, four monitoring units are connected to the temperature recorder 17. In this case, the variable resistances VR1, VR2, VR3, VR4 of the respective monitoring units are selected so as to gradually increase in value. As a result, the temperature recorder 17 has four types of reference output voltages.
Input, for example, 40 ° C., 50 ° C., 60
° C and 70 ° C are set as reference temperatures. Obedience
Thus, the resistance R3 between the pair of electrodes described above is increased due to water leakage.
When the voltage drops, the reference output voltage of each variable resistor changes.
In, the change in the recording paper 18 as a change in the respective reference temperature
It can be recorded. As a result, the lines recorded on the recording paper 18 do not overlap each other, and a large number of samples are clearly formed.
Cable monitoring can be performed simultaneously. The present invention is not limited to the above embodiment. In the above embodiment, the hygroscopic member was gauze, and the electrode was configured by binding a bare copper wire, for example. It may be configured.

[0011]

[Effects of the Invention] The water leakage detection device of the present invention described above
A hygroscopic member is arranged so as to cover the conductor of each sample cable, and the resistance change between each conductor and the hygroscopic member is measured by a pair of electrodes.
And a variable resistor to detect water leakage, so that no special agent is required, and it is hardly affected by the temperature of the atmosphere, and water leakage can be detected automatically in a short time and efficiently.
Combining a temperature recorder with multiple variable resistors
Can monitor multiple sample cables simultaneously.
In addition, the environmental temperature can be measured at the same time. Also, since it can be almost completely automated, it can be used for maintenance and inspection of various production facilities and test facilities that do not want to leak water.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a water leakage detection device of the present invention.

FIG. 2 is a schematic diagram showing the entire configuration of a conventional test apparatus for detecting water leakage.

FIG. 3 is a connection diagram showing an equivalent circuit of the monitoring unit of the present invention.

FIG. 4 is a connection diagram showing an overall configuration of the present invention.

[Explanation of symbols]

Reference Signs List 3 cable 5 conductor 10 monitoring unit 11 hygroscopic member 12 electrode plate 13A, 13B electrode 17 temperature recorder

Continuation of the front page (72) Inventor Kenji Kato 2-1-1, Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Showa Electric Cable & Cable Co., Ltd. (56) References JP-A-2-115735 (JP, A) Sho Akai 57-17431 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] (1)Apply water pressure to each end of multiple sample cables.
In addition, the presence or absence of water leakage from each other end of each sample cable is determined.
In the leak detection device that detects Conductor exposed at each other end of each sample cable
A covering hygroscopic member, Connected to each of the conductors and each of the hygroscopic members covering the conductors
Multiple pairs of electrodes, Connected between the pair of electrodes, each having a different resistance value
And a plurality of variable resistors set to Both ends of each of the variable resistors are connected in parallel, and each of the variable resistors is connected.
Changes in the reference output voltage of the resistor are recorded as temperature changes in parallel.
Water leak detection device, comprising:
Place.