JPS5875041A - Detection for leakage of water - Google Patents

Abstract

PURPOSE:To detect the leakage of water from a cooling pipe without the influence of electromagnetic induction, by measuring the quantity of light, which is charged from one ends of optical fiber lines provided in parallel under the cooling pipe, in the side of the other ends. CONSTITUTION:An extrahigh voltage power cable 6 is stored and laid in a through 7, and a water supply-side cooling pipe 8a and a return-side cooling pipe 8b are provided in parallel above the cable, and optical fiber lines 9a and 9b are provided in parallel just under cooling pipes below the cable. A detecting part 15 where a part of a protection layer 14 is cut to expose the surface of an optical fiber 13 is arranged just under a connection part 16 between cooling pipes. The optical signal charged by a light transmitter 17 is detected by a light receiver 18. If the detecting part 15 is covered with cooling water because of the leakage of water from cooling pipes, this optical signal is refracted partially; and thus, the change of the quantity of light is measured in transmission and reception ends to detect whether cooling water is leaked or not.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a water leakage detection method useful for detecting the presence or absence of water leakage from cooling pipes housed in a disaster prevention trough, for example.

(Conventional Wave Technique) In general, for cables installed inside a trough, a cooling pipe is installed in the upper part of the trough to increase the allowable current of the cable.
The cable is cooled by cooling water injected into the cooling pipe.

However, such cable lines have the disadvantage that cooling water leaks from the cooling pipes themselves or from the joints between the cooling pipes.

Conventional methods for detecting water leakage from cooling pipes include:
For example, as shown in Figure 1, a flowmeter l placed at a predetermined position.
a, 1b to measure the amount of water sent and the amount of water on the return route 2, and calculate the difference in flow rate using a microcomputer or sequence controller 3, or by arranging a pair of electrodes to which a constant DC voltage is applied in the trough, The presence or absence of conduction of this electrode I: Therefore, a method of detecting water leakage is known.

In addition, in the figure, 4 indicates a pump, and 5 indicates cooling water.

(Problems with conventional technology) However, in the former case, (a) the accuracy of the flow rate needle is poor, making it difficult to detect small-scale water leaks, and (b) Furthermore, since it requires a device such as a microcomputer to detect and judge the flow rate difference, it has the disadvantage of being 20% more expensive.

In addition, in the latter case, (a) the lead wire connecting the electrode and the power source is made of a conductor, so the lead wire receives induction from the power cable laid nearby, and is installed in this circuit. This has the drawback that the detector used in the detection method malfunctions, and for this reason, its reliability as a detection means is low, so that it can only be used as an auxiliary method.

(Objective of the Invention) The present invention was made based on the above-mentioned circumstances, and it is an object of the present invention to provide a highly reliable water leakage detection method that is not guided by small cables.

(Example of the invention) Hereinafter, the present invention will be explained based on the drawings of one embodiment.

In FIG. 2, for example, an ultra-high voltage power cable 6 is housed and installed in a trough 7, and above the cable there is a cooling pipe 3a on the water supply side, a cooling pipe 8b on the return side, and further below the cable, That is, at the inner bottom of the trough, ζ binary fiber lines 9a and 9b are provided directly below each cooling pipe, respectively.

Inside the trough 7, a partition plate 1 made of an aluminum plate or the like is installed, for example, as shown in Figure 3 ζ2, to prevent the spread of cable fire.
Each room 11a is divided into a plurality of rooms by 0.
1 to 11d include optical fiber wires 9a and 9b, which will be described later.
At least one detection section 128 to 12b is provided.

As shown in FIG. 134, the optical fiber lines 9a and 9b consist of an optical fiber 13 and a protective layer 14 covering the outer periphery of the optical fiber 13, and a part of this protective layer is cut off and exposed from the outer surface of the optical fiber 16 (hereinafter referred to as , this exposed portion is abbreviated as the detection section 15).

It is preferable that the detection unit 15 is disposed directly below the connection portion 16 of the cooling pipe indicated by the dotted line in the figure. This is because water leakage from the cooling pipes often occurs at the joints of the cooling pipes, rather than from the cooling pipe bodies.

In addition, since the protective layer of the optical fiber wire detection part (2, 1, s) is removed and is easily damaged, in order to prevent this, protect such part with a transparent resin or a glass tube, etc., if necessary. You can.

In the water leakage detection system described above, for example, one end side I of the trough: the optical transmitter 17 (optical fiber 1
A signal is introduced at 6, and this signal will be detected by optical receiver 18.

If the detection unit 15 is covered with cooling water due to water leakage from the cooling pipe, the introduced optical signal will be partially refracted at the core.

Therefore, by measuring the change in the amount of light at the transmitting and receiving end (=), it is possible to detect whether or not cooling water is leaking from the cooling pipe 1.

That is, if there is no water leakage, the amount of light at the transmitting and receiving ends will not change, but if there is water leakage, the amount of light at the receiving end will be lower than that at the transmitting end.

When water leakage is detected, an alarm (not shown) is activated and a pulp (not shown) is automatically closed, thereby stopping the injection of cooling water.

Since a cooling system is usually installed in the moxibustion system between manholes, if the information on the manholes is sent to the cooling station (not shown) (= = cable line), it will be possible to determine in which manholes water leakage occurs. to know whether it is true (two things)

(Effects of the Invention) In the above-mentioned second embodiment of the present invention, water leakage from the cooling pipes is detected using optical fiber wires, so there are the following advantages when compared with the conventional method.

(b) In the conventional method, it was difficult to detect a small amount of water leakage, but this can be easily detected with the present invention.

(b) Since detection is performed using optical fiber lines, there is no influence of electromagnetic induction from nearby electrical cables, thereby providing a reliable method of detecting water leakage that is free from malfunctions.

(c) By adjusting the porium on the receiving side, malfunctions due to dew condensation, etc. can be prevented.

In other words, in the past, if there was condensation inside the trough, there was a concern that the water droplets caused by the condensation would cause the electrodes to become conductive, but in this proposal, the detector would only activate when a certain amount of water leaked. By adjusting the receiver's polyurethane, it is possible to prevent malfunctions like those that occurred in the past.

B) Since the configuration of the control device for determining the presence or absence of water leakage is simple, the device can be manufactured at low cost, thereby providing an inexpensive water leakage detection system.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional water leakage detection method, Fig. 2 is an explanatory diagram showing a water leakage detection situation in the present invention, Fig. 6 is a sectional view taken along the line A-A' in Fig. 2, and Fig. 4 is an explanatory diagram of a water leakage detection method according to the present invention. FIG. 3 is an explanatory diagram showing a fiber wire detection section. 6 ・・・・・・・・・・・・・・・・・・・・・Cable 7 ・・・・・・・・・・・・・・・ Song/trough 8a, f3b...・・・・・・・・・・・・Cooling pipe 9
a, 9b......Optical fiber line 10......
...Partition plate 12Jl ~ 12d, 15-...Detection section 16 ...... Optical fiber 14 ...... ...Song...Protected layer representative Patent attorney Sa Suyama - Same as above Yama 1) Akinobu

Claims (1)

[Claims] 1. A cooling pipe is provided above the cable and an optical fiber line is provided below the cable in the trough in which the cable is housed, and the amount of light introduced from one end of the optical fiber line is controlled by the other. A water leakage detection method, characterized in that the presence or absence of water leakage from the cooling pipe is detected by measuring at the end side. 2. The water leakage detection method according to claim 1, characterized in that the optical fiber line is located on a vertical line of the cooling pipe. 3. The inside of the trough is divided into a plurality of chambers by a partition plate, and in each of the divided chambers, it is confirmed that there is at least one part where the optical fiber is exposed for a required length due to peeling off the protective layer of the optical fiber wire. Characteristic claim 1
Water leakage detection method described in section. 4. The water leakage detection method according to claim 13, wherein the exposed portion of the optical fiber is located below the connection portion of the cooling pipe.