JP4638391B2 - Liquid quality sensor and fixing structure of liquid quality sensor - Google Patents

Description

  The present invention relates to a liquid quality sensor for detecting a change in liquid quality such as a liquid leak from a condenser or the like of a thermal power generation facility, for example, a device through which seawater flows, and a fixing structure of the liquid quality sensor.

  Conventionally, in a thermal power generation facility or the like, steam generated in a boiler is cooled and condensed by a condenser and circulated and used as boiler water (pure water). Here, a cooling pipe for cooling the steam in the condenser is provided, and seawater for cooling flows through the cooling pipe. However, when a crack or the like occurs in the cooling pipe, seawater leaks from there. Then, it is mixed in the condensed boiler condensate, and the condensed water is mixed with salt to corrode various pipes. Therefore, various seawater leakage detection devices have been developed to check for seawater leakage from the condenser (see, for example, Patent Document 1).

  However, in the case of the above-described prior art, since the boiler water condensed at the lower part of the condenser is collected and subjected to liquid analysis, the leaked seawater is significantly diluted with the boiler water, and the detection sensitivity is lowered accordingly. is there. In addition, the actual seawater leak is caused by cracking a part of the condenser, but in the case of the above technology, it is impossible to specify which part of the condenser is leaking, and it takes time to deal with it. ,There's a problem.

  Therefore, the present applicant has previously proposed a leak detection device as shown in FIG. 10 (Patent Document 2). As shown in FIG. 10, the conventional leak detection apparatus is installed below the target device 200 for liquid leak detection, and in a first direction parallel to one direction and a second direction intersecting with the one direction. The electrical conductivity between the metal wires 2A to 2H, 3A, and 3B that are arranged and separated from each other and any metal wire in the first direction and any metal wire in the second direction is increased. At this time, there is provided leak position specifying means 201 for specifying the position where the metal wires intersect at that time as the leak position of the target device (see FIG. 1 of Patent Document 2).

JP 2001-141596 A JP 2004-144708 A

  However, the leak detection apparatus according to Patent Document 2 is installed below the leak detection target device, and tries to detect a change in resistance between electrodes due to a difference in electrical conductivity when seawater and condensed water fall. Yes. In this method, seawater diluted with water is mixed in compared to the change in electrical characteristics between the electrodes when dripping water enters between the electrodes and when it does not (space or water vapor exists between the electrodes). In order to detect seawater dripping with small changes in electrical characteristics due to the sensor, it is necessary to stretch the sensor in a plane and very densely, and it is difficult to detect scattered seawater There's a problem.

  Therefore, in order to make it possible to detect the scattered seawater, as shown in FIG. 9, a pair of center electrode 301 and outer conductor 302 are insulated from each other by an insulator 303 in a falling water recovery tank, and the insulator Developed a liquid leak detection sensor 300 in which a V-groove 304 is provided in 303 and a part of the center conductor 301 is exposed. For example, a resistance between a pair of conductors is measured by a TDR (Time Domain Reflectometry) device (not shown). (Japanese Patent Application 2005-54910, filed February 28, 2005).

However, when forming the long part of the continuous liquid leak detection sensor 300 having the exposed portion 305 on the insulator 303, the exposed portion 305 is provided on the insulator 303, so that the central conductor 301 located at the center is well formed. There is a problem that it cannot be stored and jumps out. This is a problem both at the time of manufacture and at the time of use, and there is a problem that a qualified measurement cannot be performed.
For this reason, there is a problem that it is difficult to accurately detect minute liquid leakage of seawater in a wide area such as a condenser.

  In view of the above problems, an object of the present invention is to provide a liquid quality sensor capable of stably detecting a liquid leak such as seawater leak of a condenser with high sensitivity and a fixing structure of the liquid quality sensor. And

A first aspect of the present invention for solving the above-described problem is a liquid quality sensor comprising a pair of conductors for detecting a change in liquid quality in a solution, which is formed continuously in the axial direction, and is substantially V An insulator having a first groove having a letter-shaped opening and a second groove formed in communication with the first groove; a central conductor buried in the second groove; and the central conductor with pressing, the a liquid-capable holding member to the center conductor to be filled in the first groove side, the pressing in a state of pressing the central conductor by a member, presser have covered the entire member and the insulator, and liquid permeation And a liquid quality sensor having an external conductor.

  A second invention is the liquid quality sensor according to the first invention, wherein the first groove portion and the second groove portion are linearly or spirally formed in the axial direction.

  A third invention is the liquid quality sensor according to the first or second invention, wherein the central conductor is a stranded wire made of a nickel wire, and the outer conductor is a knitted nickel wire.

  A fourth invention is a structure for fixing a liquid quality sensor that is fixed to a wall surface of a solution tank in which a solution is stored, and is arranged in a layer with a predetermined interval in order to detect the liquid quality in the solution tank. The liquid quality sensor according to any one of claims 1 to 3, a fixing plug provided at an end of the liquid quality sensor, and provided with confidentiality from the outside of the solution tank, The liquid quality sensor fixing structure has a fixing adapter connected to a fixing plug.

  According to the present invention, the central conductor can be reliably installed, and a change in liquid quality can be reliably detected over a wide range, for example, seawater leak in a condenser can be detected with high sensitivity and stability. It becomes possible.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

A liquid quality sensor according to a first embodiment of the present invention will be described with reference to the drawings.
Hereinafter, in this embodiment, a liquid leak detection sensor will be described as an example of the liquid quality sensor.
FIG. 1 is a cross-sectional view of a liquid leakage detection sensor which is a specific example of the liquid quality sensor according to the first embodiment.
As shown in FIG. 1, a liquid leak detection sensor 10 according to the present embodiment is a liquid leak detection sensor comprising a pair of conductors for detecting a change in liquid quality in a solution, and is formed continuously in the axial direction. The first groove portion 11 having a substantially V-shaped opening, and an insulator 13 having a second groove portion 12 formed so as to communicate with the first groove portion 11, and the second groove portion 12 are buried. The center conductor 14 is held by the core-shaped center conductor 14, the pressing member 15 that holds the central conductor 14, and is buried on the first groove 11 side, and the pressing member (for example, a stranded wire made of wires 15 a to 15 d) 15. It has the outer conductor 16 which covers the whole insulator 13 in the pressed state.

  In the present invention, the second groove portion 12 in which the center conductor 14 is installed and the first groove portion 11 in which the pressing member 15 for holding the center conductor 14 is installed have a two-stage configuration. The pressing member 15 is installed in the one groove portion 11, and the whole is covered with the external conductor 16 in this state, thereby preventing the center conductor 14 from jumping out from the insulator 13.

  Here, the liquid quality change in the present invention is not limited to the one in which the signal changes due to the drop, intrusion, or diffusion of a solution different from the solution in which the liquid quality sensor is immersed, for example, an X-ray or the like Such a component that changes (degrades, diffuses, etc.) the constituent elements of the liquid quality by the excitation action of a medium such as light or sound is also included. Also included are changes in factors over time, such as changes in the medium itself.

  Here, it is preferable that the center conductor 14 is made of a metal wire (particularly pure nickel) and a plurality of wires are formed in a twisted wire shape.

  Further, the insulator 13 is formed by integrally forming a two-step groove of the first groove portion 11 and the second groove portion 12, and is preferably made of, for example, polyethylene.

  The holding member 15 that puts the central conductor 14 in the second groove 12 and holds it so as not to protrude is made of a plurality of insulated wires twisted together.

  The outer conductor 16 is made of a metal wire (especially pure nickel) in a net shape, and maintains a predetermined positional relationship from the center conductor 14 via the insulator 13.

Here, the ratio between the diameter of the central conductor 14 and the inner diameter of the outer conductor 16 is preferably 2 to 5, for example.
The diameter ratio of the outer conductor is preferably set to 0.01 to 0.2, for example, of the entire diameter of the liquid leak detection sensor 10.
The dielectric constant (relative dielectric constant / conductor ratio) of the insulator 13 is preferably 0.5 to 1.5, for example.

The volume resistivity of the insulator 13 is preferably 10 ¹⁰ Ω · m or more, for example. For example, in the case of polyethylene, the volume resistivity is preferably 10 ¹⁴ Ω · m or more.
Further, the relative permeability of the insulator 13 is preferably 0.5 to 2, for example. For example, the relative permeability of a resin such as polyethylene is about 1.

  As a specific example of the liquid leak detection sensor 10, the thickness of the central conductor 14 is, for example, 3.5 mm, the thickness of the external conductor 16 is 0.5 mm, the outer diameter of the insulator 13 is 12 mm, and the external conductor The outer diameter of 16 is preferably 13 mm.

Further, as shown in FIG. 2, the first groove portion 11 and the second groove portion 12 may be linear along the axis, or as shown in FIG. You may do it.
Thereby, when changing the direction of a groove | channel, it is not necessary to change a direction at the time of construction, and construction becomes possible easily.

As shown in FIG. 4, when the liquid leak detection sensor 10 is wound around the drum 20, the cable groove is set in advance according to the construction direction and the unwinding direction from the drum 20 during manufacture. You may do it.
That is, the groove direction may be changed for each length corresponding to the construction position so that the liquid leakage detection sensor 10 rotates the groove one turn with respect to the length for winding the drum 20 once. .
The liquid leak detection sensor 10 may be manufactured while adjusting the direction of the groove by combining desired directions at the time of construction.

  As a result, when it is desired to construct the groove in a specific direction, it is not necessary to twist the cable during construction, and the construction can be easily performed.

Here, the reason why the pressing member 15 is made of a stranded wire is to make it easy for a leaked liquid to enter from between the stranded wires so as to instantly sense a change in liquid quality due to leakage.
Further, in the present invention, the pressing member 15 is not limited to one made of a stranded wire, and as shown in FIG. 5, for example, a plurality of pores 15a are formed in the pressing member 15, and the pores 15a are passed. A leaked liquid may be detected.

Next, FIG. 6 shows an example of a liquid leak detection apparatus which is an example of a liquid quality inspection apparatus using such a liquid leak detection sensor.
As shown in FIG. 6, the liquid leakage detection device 70, which is an example of a liquid quality inspection device, applies a pulse voltage between the liquid leakage detection sensor 10 according to the first embodiment and the pair of conductive wires. A liquid leakage position specifying device 71 that specifies the liquid leakage position of the target device based on the time until the reflected voltage returns between the conductive wires is provided. The condenser 101 has a plurality of cooling tubes 101a, and seawater 102 as cooling water flows into the cooling tubes 101a. The steam 106 from the boiler is cooled by the cooling tube 101a, becomes condensed water 103, and is recovered in a recovery tank below the condenser 101. A liquid leak detection sensor 10 is immersed in the recovery tank at a predetermined distance from the liquid surface.

In FIG. 6, the liquid leak detection sensor 10 and the liquid leak position specifying device 71 are connected by a signal line 72, process the detection result, and display the result on the monitor 73 as a warning.
This display indicates the signal intensity, the presence / absence of liquid leakage from the signal intensity, and the location thereof.

FIG. 7 shows an example of a fixing structure between the signal line 72 and the liquid leak detection sensor 10 installed in the collection tank.
As shown in FIG. 7, the liquid quality sensor fixing structure 50 according to this embodiment is a liquid quality sensor fixing structure that is fixed to a wall 51 of a recovery tank that stores condensed water of a condenser, for example. In order to detect the liquid quality in the tank, the liquid leak detection sensor 10 disposed in the layer with a predetermined interval, the fixing plug 52 provided at the end of the liquid leak detection sensor 10, and the The fixing adapter 53 is provided on the wall 51 while having confidentiality from the outside of the recovery tank and is connected to the fixing plug 52.

The fixing adapter 53 is provided with a liquid seal by a plurality of O-rings 54 so as to maintain confidentiality.
The concave portion of the first contact 52a in the fitting portion of the fixing plug 52 and the tip of the central conductor 14 are connected, and the outer conductor 16 and the metal fixing plug 52 are connected by fastening the nut 55. Thus, the inside and the outside are both conducted. A sealing member 56 is provided inside the fixing plug 52.

  Further, a second contact 53a is provided at the central portion of the fixing adapter 53, and a tip portion of the first contact 52a that is electrically connected to the central conductor 14 of the liquid leak detection sensor 10 and a concave portion between the second contact 53a. The fixing plug 52 and the fixing adapter 53 which are connected and are electrically connected to the outer conductor 16 side are fastened via a coupling 57 so as to ensure conduction. Note that an external signal line 72 as shown in FIG. 6 is connected to the fixing adapter 53, and a signal is sent to the liquid leakage position specifying device 71, where the detection result is processed and the result is sent to the monitor 73. Is displayed as a warning.

  Therefore, there is no deterioration in the propagation characteristics of the liquid leak detection sensor 10 when penetrating the wall 51 of the recovery tank, and the confidentiality is improved. Therefore, the extent and position of seawater leak are accurately identified from the impedance distribution. be able to.

FIG. 8 is an example showing a TDR measurement test result when the detection of seawater leak is simulated using the liquid leak detection device 70 of FIG.
In the test, a section of about 10 m of the liquid leak detection sensor 10 is spirally installed in a 750 × 750 mm container, submerged in circulating pure water, and TDR measurement is performed when seawater is locally dripped. went.

  As shown in FIG. 8, it was found that a change in impedance occurred in a part (4 m to 5 m and 7 m to 8 m) of the liquid leak detection sensor 10 immersed in water, and the change increased with time.

  In general, a condenser is a unit in which a structure in which a thin tube extending in the longitudinal direction is bent 180 degrees in a direction perpendicular to the same on a single plane and then folded back in the longitudinal direction is defined as one unit. A large number of layers are stacked in the direction. And the cooling seawater which flowed in from the entrance side of a thin tube cools the boiler vapor | steam sprayed on the outer side of a condenser, makes it condensed water, and flows out from the exit side of a thin tube. The condensed water is stored in a recovery tank installed below, and then reused as circulating water.

  In such a plurality of narrow tubes, for example, when leakage due to seawater corrosion occurs, seawater leaks from the corroded portion and falls into the recovery tank. Since the recovery tank is only condensed water, the liquid leak detection sensor usually shows an almost constant value, but when seawater falls, the ion concentration in the falling part changes, and this change is detected as a change in electrical conductivity. You can identify leaks.

  In the above embodiment, the condenser is exemplified as the liquid leakage target device. However, the present invention is not limited to this, and the liquid leakage detection sensor according to the present invention is applied to the liquid having different properties from the liquid leakage. It is possible to accurately detect leakage by installing and measuring the signal intensity in the TDR device.

  As described above, the liquid quality sensor according to the present invention can reliably detect a liquid leak over a wide range, and is suitable for, for example, detecting a seawater leak of a condenser with high sensitivity and stability. .

It is the schematic of the liquid leak detection sensor which concerns on a present Example. It is a perspective view of the liquid leak detection sensor which concerns on a present Example. It is a perspective view of the other liquid leak detection sensor which concerns on a present Example. It is a perspective view of the pressing member which concerns on a present Example. 1 is a schematic cross-sectional view of a liquid leak detection sensor according to Embodiment 1. 6 is a schematic diagram of a liquid leakage detection apparatus according to Embodiment 2. FIG. 6 is a schematic diagram illustrating a fixing structure of a liquid leakage detection sensor according to Embodiment 2. FIG. It is a figure which shows the TDR measurement test result at the time of simulating the detection of seawater leak. It is sectional drawing of a liquid leak detection sensor. It is a figure which shows the TDR measurement test result of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid leak detection sensor 11 1st groove part 12 2nd groove part 13 Insulator 14 Center conductor 15 Holding member 16 Outer conductor 101 Condenser 102 Seawater 103 Condensed water

Claims (4)

A liquid quality sensor comprising a pair of conductors for detecting a change in liquid quality in a solution,
An insulator having a first groove formed continuously in the axial direction and having a substantially V-shaped opening; and a second groove formed in communication along the first groove;
A central conductor buried in the second groove,
A pressing member that presses the central conductor and is permeable to the central conductor buried in the first groove,
The pressing in a state of pressing the central conductor by a member, liquid quality sensor and an external conductor having the entire not covered, and liquid-permeable presser and member insulator. In claim 1,
The liquid quality sensor, wherein the first groove portion and the second groove portion are linearly or spirally formed in the axial direction. In claim 1 or 2,
The liquid sensor according to claim 1, wherein the central conductor is a stranded wire made of a nickel wire, and the outer conductor is a nickel knitted wire. A fixing structure of a liquid quality sensor that is fixed to a wall surface of a solution tank in which a solution is stored,
The liquid quality sensor according to any one of claims 1 to 3, wherein the liquid quality sensor is disposed in the layer with a predetermined interval for detecting the liquid quality in the solution tank;
A fixing plug provided at an end of the liquid quality sensor;
A fixing structure for a liquid quality sensor, comprising: a fixing adapter provided with confidentiality from the outside of the solution tank and connected to the fixing plug.

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