JPH0752603Y2 - Leak detection line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a liquid leakage detection line for detecting damage to a pipeline or a storage tank that transports liquids such as sulfuric acid and caustic soda.

[Prior Art] The applicant of the present invention can detect a leak over a wide range by previously installing it in a pipeline or a storage tank for transporting a liquid such as sulfuric acid or caustic soda, and detecting the leak over a wide range. I proposed a line (see Japanese Utility Model Application No. 61-151259).

The liquid leakage detection line is composed of a pair of electrode wires made of a conductor coated with an insulating layer made of a polymer material having an ester bond, and an inner braid made of a non-liquid absorbing synthetic fiber yarn and a liquid absorbing layer on the outer circumference. And an external braided body made of yarn. And, specifically, the inner braid is not only liquid-absorbing but also non-liquid-soluble, for example, a monofilament-like polyethylene fiber yarn is used, and the outer braid is not only liquid-absorbing but also liquid-soluble multifilament-shaped. Polyester fiber yarn was used.

In the above leak detection line, when a leak such as sulfuric acid occurs, the liquid-absorbing and liquid-soluble outer braid absorbs it, and the non-liquid-absorbing and non-liquid-soluble inner braid holds it. Then, sulfuric acid or the like that permeates through the inner braid dissolves the insulator layer, and a short circuit or a state close to a short circuit is formed between the pair of conductors of the electrode wire. Therefore, the leakage can be detected by measuring the insulation resistance between the conductors from one end of the leakage detection line. Even if normal water enters the leak detection line due to rainfall or the like, the insulator layer does not dissolve, so that no malfunction occurs.

[Problems to be solved by the device]

In the above-mentioned conventional liquid leakage detection line, liquid leakage such as sulfuric acid enters the outer braid → the inner braid → the insulator layer in order,
It takes a certain amount of time from the occurrence of liquid leakage to its detection. However, in the conventional liquid leakage detection line, the time from the occurrence of liquid leakage until the insulator dissolves and the resistance value between the conductors of the electrode wires falls below a predetermined value, that is, the detection time, is However, there was a problem in that there was a large difference and the variation was large. If there is a large variation in the detection time, it becomes difficult to set the specification that the leak is detected within a predetermined time, and the reliability thereof is also reduced.

The present invention has been made in view of such problems of the conventional technique, and an object of the present invention is to provide a liquid leakage detection line with extremely small variation in liquid leakage detection time.

[Means for Solving the Problems]

In order to achieve the above object, the liquid leakage detection wire of the present invention has electrode wires covered with an insulator made of a polymer material having an ester bond on a conductor and arranged substantially parallel to each other. In a liquid leakage detection line formed by sequentially covering braids, the inner braids are alternately arranged with groups of non-liquid-soluble and non-absorbent yarns and groups of liquid-soluble and liquid-absorbent yarns. The outer braid is composed of liquid-soluble, liquid-absorbent and weather-resistant yarn.

[Action]

By arranging the inner braid with groups of non-liquid-soluble and non-liquid-absorbing yarns and groups of liquid-soluble and liquid-absorbing yarns alternately arranged, liquid leakage and liquid absorption The group of non-liquid-soluble and non-absorptive yarns dissolves and the liquid-absorbent liquid is absorbed while the group of non-liquid-soluble yarns quickly dissolves and secures the passage of the leakage liquid to the insulator. The leaked liquid in which the sexual thread is dissolved is prevented from diffusing to the periphery and held until the insulator is dissolved.
Therefore, as in the case where the inner braid is composed of only non-liquid-soluble and non-liquid-absorbing yarns, the degree of influence of the leakage of liquid is affected by the degree of coarseness and denseness of the braid of the inner braid and the change over time. Furthermore, since the outer braid has not only a mechanical protection function but also excellent weather resistance, the inner braid is prevented from changing over time due to the weather and the like, and the predetermined operation of the inner braid is maintained.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a liquid leakage detection line of the present invention, and FIG. 2 is a structural diagram of an internal braid.

In FIG. 1, reference numeral 1 is a conductor having a circular cross section, 2 is an insulator coated on the conductor 1, and an electrode wire 3 is formed from these, and a pair of electrode wires 3, 3 are arranged substantially in parallel. Yes (may be twisted). Reference numeral 4 is an inner braid covering the outer circumferences of the pair of electrode wires 3, 3, and 5 is an outer braid.

The insulator 2 is a polymer material having an ester bond,
Resins produced by polycondensation of polyhydric organic acids and polyhydric alcohols, and various resins can be obtained depending on the difference between organic acids and alcohols. Either of them may be used,
In particular, the unsaturated polyester resin is also preferable because it has water resistance and can be readily dissolved in sulfuric acid or caustic soda.

As the non-liquid-soluble, non-liquid-absorbing thread forming the inner braid 4, for example, a monofilament-like thread made of fibers such as polyethylene and polypropylene is suitable. Further, as the liquid-soluble and liquid-absorbent yarn which is used in combination with the non-liquid-soluble and non-liquid-absorbent yarn, for example, a multifilament yarn made of fibers such as polyester and tetron is suitable. Figure 2 shows a non-liquid-soluble, non-liquid-absorbing thread 4a.
An example of the braid of the group consisting of and the group consisting of the liquid-soluble and liquid-absorbent yarn 4b is shown. The group of yarns refers to one yarn or a plurality of yarns gathered together from one supply reel when braiding. In the illustrated example, left-handed thread,
An inner braided body 4 is shown in which the right-handed yarns are arranged alternately with two monofilament-like yarns 4a and four striking and two multifilament-like yarns 4b and four striking. . When a leak liquid such as sulfuric acid or caustic soda is touched, the leak liquid is absorbed in the multifilament yarn 4b, and the multifilament yarn 4b is melted. However, since the monofilament-shaped thread 4a remains in the lattice shape, the leaked liquid in which the multifilament-shaped thread 4b is dissolved dissolves the insulator 2 while being held by this lattice.

The outer braid 5 has a mechanical protection function such as relaxing the pressure applied to the insulator 2 of the electrode wire 3 via the inner braid 4 at the binding portion or the like. As the liquid-soluble, liquid-absorptive, and weather-resistant yarn forming the outer braid 5, for example, a black multifilament yarn made of polyester fiber is preferable. When a leak of sulfuric acid or caustic soda occurs, the liquid-absorbing and liquid-soluble outer braid 5 first absorbs it, and the monofilament-shaped yarn 4a of the inner braid 4 is held. In particular, since the outer braid 5 has weather resistance due to black color, the outer braid 5 absorbs sunlight rays such as ultraviolet rays,
The inner braid 4 particularly prevents non-liquid-soluble and non-liquid-absorbing yarn 4a from changing over time.

Also, at the liquid leakage site, the black outer braid 5 and the group of liquid-soluble and liquid-absorbent threads 4b of the inner braid 4 are dissolved,
A group of non-liquid-soluble and non-liquid-absorbent white threads of the inner braid 4
Since only 4a remains, the white color of the non-liquid-soluble / non-absorptive thread 4a remaining at the leak location can be clearly seen in the black color of the outer braid 5 around the leak location, and the leak location can be found. Is easy.

Next, the results of measuring the leak detection performance with respect to sulfuric acid in the present invention example and the comparative example described below will be described.

In the present invention example, a pair of electrode wires 3 is made of a copper conductor 1 having a diameter of 0.65 mmφ and an insulator 2 coated with polyester having a thickness of 15 μm and twisted at a pitch of 20 mm to have an outer diameter of 1.36 mm. , The inner braid 4 was arranged by alternately arranging two 100-denier twin-threaded black Tetron yarns with four strokes and two 200-denier single-thread white polyethylene yarns with four strokes for a total of 16 strokes.
Using an outer diameter of 2.16 mm (thickness 0.40 mm) that was braided with 9 mm, the outer braid 5 was braided with four 100 denier twin yarn black Tetron yarns with 24 strokes at a pitch of 16 mm. Is 2.
86 mm (thickness 0.35 mm) was used as a detection line sample with a length of about 1 m.

The comparative example is a book except that the inner braid 4 is braided with two 200-denier double-threaded white polyethylene yarns with 16 strokes at a pitch of 9 mm and a coating outer diameter of 2.16 mm (thickness 0.40 mm). It is the same as the devised example.

Then, 20 new articles of the present invention and 20 new articles of the comparative example were prepared, and a sulfuric acid dropping test was conducted on each of the 20 new articles using the apparatus of FIG.

In FIG. 3, the detection sample 11 having a length of about 1 m is placed on the pad 12, the conductors on the electrode wires at both ends are exposed, and a 5 kΩ resistor 13 is connected to one end by a clip 14 and the other end is connected. A leak detector 15 with a recorder 16 was connected with a clip 14.
The liquid leakage detector 15 is, for example, an AC power supply for applying an AC voltage between the electrode wires, and a current flowing by the voltage application is converted into a DC voltage by a circuit resistance or a rectifier circuit inserted in the voltage application circuit and compared with a reference voltage value. Then, the generation of the abnormal current is detected, and the recorder 16 records the change in the DC voltage. Then, a buret 17 was installed in the upper middle of the detection sample 11, sulfuric acid having a concentration of 98% was dropped at a rate of 0.02 ml / sec, and the time (minute) until the insulation resistance reached 5 kOhm or less was measured.

The results are shown in Table 1 and FIG.

As shown in Table 1 and FIG. 4, the comparative example has a standard deviation of 1 minute.
While the variation is 38 seconds, the standard deviation of the present invention example is 18 seconds, which is reduced to about 18%. In addition, the average value is 3 minutes and 53 seconds in the comparative example, while it is 3 minutes and 32 seconds in the present invention example.
Seconds, it has decreased to about 91%. As a result, in the maximum value, the present invention example is reduced to 65.8% of the comparative example, and the reliability for the detection time is high, so it is easy to set the specification that the leak is detected at the predetermined time, and the reliability is also high. Become.

[Effect of device]

In the liquid leakage detection line of the present invention, the inner braid is formed by alternately arranging groups of non-liquid-soluble, non-liquid-absorbing threads and groups of liquid-soluble, liquid-absorbing threads. The outer braid is composed of liquid-soluble, liquid-absorbent and weather-resistant yarns, and the group of liquid-soluble liquid-absorbent yarns is quickly dissolved by the liquid leakage to secure a passage for the liquid leakage to the insulator. , The non-liquid-soluble, non-liquid-absorbing thread group neither dissolves nor absorbs liquid, and prevents leakage of liquid from spreading to the surroundings and holds it until the insulator dissolves. Becomes extremely small, which facilitates the specification setting of detecting a leak within a predetermined time, and improves its reliability. In addition, since the outer braid has a mechanical protection function and is excellent in weather resistance, the inner braid is prevented from changing over time due to the weather, etc. Can withstand long-term use.

[Brief description of drawings]

FIG. 1 is a sectional view of the liquid leakage detection line of the present invention, FIG. 2 is a structural diagram of an internal braid, FIG. 3 is a diagram showing an inspection device for the liquid leakage detection line, and FIG. 4 is a liquid leakage detection time. It is a graph showing variation. 1 ... Conductor, 2 ... Insulator, 3 ... Electrode wire, 4 ... Internal braid,
4a ... Non-liquid-soluble, non-liquid-absorbing yarn, 4b ... Liquid-soluble, liquid-absorbing yarn, 5 ... External braid.

Claims (1)

[Scope of utility model registration request] 1. A conductor is provided with a pair of electrode wires coated with an insulator made of a polymer material having an ester bond, which are substantially parallel to each other, and the outer periphery of which is sequentially covered with an inner braid and an outer braid. In the liquid leakage detection line, the inner braid is formed by alternately arranging groups of non-liquid-soluble and non-absorbent yarns and groups of liquid-soluble and liquid-absorbent yarns, and the outer braid is A leak detection line comprising a soluble, liquid-absorbing, and weather-resistant thread.