JP5317854B2 - Conductive fluid detector - Google Patents

Description

  The present invention relates to a conductive fluid detector used to detect the presence of a conductive fluid such as a fluid metal, and more specifically, the leakage of a conductive fluid from a portion where the conductive fluid is stored. The present invention relates to a highly reliable conductive fluid detector that is highly reliable and can be used stably without malfunction due to dust, container deformation, or the like.

There are various types of conductive fluid detectors, but the basic principle is that one or more conductive wires are arranged in parallel to change the electrical characteristics between the conductive wires or between the conductive wires and other conductors. Many detections are used.
For example, the most common conductive fluid detector for detecting leakage of a liquid metal such as a fast breeder reactor is often used as an electrode type. This is done by passing a conductive wire through a bead-shaped insulator and detecting a decrease in the electrical resistance caused by the contact electrode projecting from the tip of the leading insulator contacting the conductive fluid. It detects the presence of sex fluid. This electrode-type conductive fluid detector is very simple and is often used as a conductive water leak detection means.

  Conductive conductive fluid detectors that measure the conduction resistance between the contact electrodes and issue an alarm upon conduction are commercially available from many control equipment manufacturers, and there are almost no problems with their electrical circuits. However, the conductive fluid detector applied to many conductive fluids other than water has various problems peculiar to the applied conductive fluid. If each problem is not solved, it is actually used as a conductive fluid detector. I can't do that.

  When the conductive fluid to be applied is water, the water has a small surface tension, good wettability with many metals, and the insulator used for the conductive wire between the contact electrode and the measuring instrument can be used sufficiently with plastic. . Even when heat resistance, corrosion resistance against acids, alkalis, etc. must be taken into account, it is generally sufficient to use stainless steel, copper, nickel or the like as the conductor and fluorine resin or polyimide resin as the insulator.

  On the other hand, in the case of molten metal such as molten aluminum, there are various problems in the materials and shapes of conductors and insulators, their arrangement, or attachment to equipment depending on the characteristics of each metal. For example, the corrosive problem of aluminum having a high melting point is typical. In addition, in order to introduce mercury that has a high surface tension and poor wettability to the electrode to the contact electrode even if it is a metal at normal temperature, use a fluorine coated resin with poor wettability or use mercury from the soot. It is necessary to take measures such as installing a mercury reservoir to collect a certain amount.

In FIG. 5, conductive wires 24 and 24 are passed through a bead-shaped insulator 21 as an insulator, and conductive fluids 24 and 24 led out from the end face of the leading insulator 21 are used as contact electrodes 25 and 25. The conventional example of a detector is shown. In FIG. 5, such a conductive fluid detector is attached to the container-like member 22, and the conductive fluid flowing out to the bottom of the member 22 is detected.

  The conductive fluid detector in which the conductive wires 24 and 24 are passed through the bead-shaped insulator 21 as an insulator is simple in structure and low in cost. However, the portions between the conductive wires 24 and 24 are opened between the insulators 21, and conductive foreign substances such as wires, metal pieces, and metal powders are likely to adhere to the gaps of the insulators 21, which causes malfunction. . In addition, a malfunction can also occur due to a short circuit caused by mutual contact or the like at the intermediate portion of the conductive wires 24, 24 reaching the contact electrodes 25, 25 provided on the insulator 21 at the tip. Furthermore, a conductive foreign material such as metal powder adheres to the end face of the tip insulator 21 provided with the contact electrodes 25, 25, or further provided on the end face of the tip insulator 21 as shown in FIG. A malfunction also occurs when the contact electrodes 25, 25 come into contact with the protruding deformation portion 23 of the member 22.

JP 2008-26264 A JP 2002-277341 A JP 2000-131178 A Japanese Patent Laid-Open No. 11-72408 Japanese Patent Laid-Open No. 08-303964

In view of the problems in the conventional conductive fluid detector, the present invention is less likely to cause malfunctions caused by short-circuiting of the intermediate portion of the conductive wire, adhesion of foreign matter on the front end surface, contact with deformed protrusions of the member, and the like. Provided is a conductive fluid detector that can be applied to a molten metal such as aluminum having a melting point , and can also be applied to observation and measurement by means other than copper wires such as a fiberscope and a thermocouple pH electrode. For the purpose.

In the present invention, in order to achieve the above object, the conductive wires 4 and 4 are accommodated in a metal tube-like sheath 1 and an inorganic insulating material powder 5 such as magnesia powder is filled between the conductive wires 4 and 4 and the sheath 1. And use an insulated sheath cable. Further, the tips of the conductive wires 4 and 4 exposed from the sheath 1 and the inorganic insulating material powder 5 are contact electrodes 6 and 6, and the cover 1 is provided by extending the sheath 1 beyond the contact electrodes 6 and 6. The cover portion 2 is provided with a window-like opening 3 through which a conductive fluid flows. In addition, a monitor pipe 8 penetrating through the sheath 1 from the cover 2 to the opposite end of the sheath 1 is provided.

That is, the conductive fluid detector according to the present invention has the contact electrodes 6 and 6 at the tip, and detects the electrical continuity by the conductive fluid in contact with the contact electrodes 6 and 6 to detect the presence of the conductive fluid. A sheathed cable in which conductive wires 4 and 4 are housed in a metal tube-shaped sheath 1 and an insulating material powder 5 such as magnesia powder is filled between the conductive wires 4 and 4 and the sheath 1 for insulation. The opening 1 is formed by cutting the side surface near the distal end of the sheath 1 into a window shape, and the inorganic insulating material powder 5 is led out from the opening 3 to form the hollow cover 2. The contact electrodes 6 and 6 connected to the conductive wires 4 and 4 are led out from the end face of the inorganic insulating material powder 5 into the cover portion 2, and the end portion on the opposite side of the sheath 1 from the cover portion 2. monitoring pipe 8 which penetrates through the same sheath 1 over It is those provided.

In this case, the contact electrodes 6 and 6 are preferably integrally connected to the conductive wires 4 and 4 passing through the inside of the sheath 1. Further, two ends of the conductive wires 4 and 4 led out from the inorganic insulating material powder 5 in the cover portion 2 are joined to each other, and two conductive wires 4 and 4 are provided for each contact terminal 6 and 6 of one pole. Should be assigned. Thereby, even if there is a trouble such as disconnection in one conductive wire 4, electrical continuity can be secured by the other copper wire 4.

In such a conductive fluid detector, the conductive wires 4 and 4 are covered with the continuous sheath 1 and the inorganic insulating material powder 5 is filled between the sheath 1 and the conductive wires 4 and 4. The conductive wires 4 and 4 do not come into contact with foreign matter, and the conductive wires 4 and 4 do not come into contact with each other, so that a malfunction due to a short circuit can be reliably prevented. Further, since the monitor pipe 8 is provided in the sheath 1, a fiberscope is inserted into the monitor pipe 8 to visually observe the state of the tip of the conductive fluid detector, or a thermocouple or the like is measured therein. Observation, measurement, and the like by means other than the conductive wires 4 and 4 are possible, such as measuring the temperature and hydrogen concentration at the tip of the conductive fluid detector by inserting a temperature element, pH electrode, and the like.

It is sectional drawing which shows one Example of the electroconductive fluid detector and its adapter part by this invention. It is a principal part perspective view of the front-end | tip part of one Example of the electroconductive fluid detector by this invention. It is a principal part perspective view of the front-end | tip part of the other Example of the electroconductive fluid detector by this invention. It is a principal part perspective view of the front-end | tip part of the comparative example with respect to this invention of an electroconductive fluid detector . It is the schematic sectional drawing which showed the prior art example of the electroconductive fluid detector with the usage example.

In the present invention, in order to achieve the object, an inorganic insulating cable is used, a cover portion is provided at the distal end portion of the sheath, a contact electrode is disposed therein, and the distal end surface of the cover portion is covered with the end surface cover 7. It was.
Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  An inorganic insulated cable is used as a cable member for the conductive fluid detector. As shown in FIG. 2, one or more conductive wires 4 and 4 are accommodated in a tubular sheath 1 made of stainless steel tube or the like, and magnesia powder or the like is further interposed between the sheath 1 and the conductive wires 4 and 4. The inorganic insulating material powder 5 is filled. The sheath and the conductive wires 4 and 4 and the conductive wires 4 and 4 are insulated from each other by the inorganic insulating material powder 5.

  In the embodiment shown in FIG. 2, a two-core sheath cable in which two conductive wires 4 and 4 are housed in a sheath 1 is used. Further, in this example, a tube pipe having a smaller diameter is inserted as a monitor pipe 8 for introducing a fiberscope on the central axis of the sheath 1.

  As shown in FIG. 2, both side surfaces of the distal end portion of a tubular sheath 1 made of stainless steel or the like are cut out in a window shape, and openings 3 are provided on both side surfaces of the distal end portion of the sheath 1. Further, the inorganic insulating material powder 5 inside the sheath 1 at the opening 3 is discharged and removed, and the portion becomes the hollow cover portion 2. Inside the cover portion 2, the tips of the conductive wires 4, 4 are led out into the cover portion 2 from the end face of the partially removed inorganic insulating material powder 5. Contact electrodes 5 and 5 are used. The end surface of the cover portion 2 that is hollow inside is closed, and this sealed and closed portion is the end surface cover 7.

FIG. 1 shows a tip portion of the conductive fluid detector and an adapter portion connected to electrode lead wires 12 and 12 for connecting the conductive wires 4 and 4 to a measurement circuit.
The ends of the conductive wires 4 and 4 opposite to the contact electrodes 6 and 6 are led out from the sheath 1 and the inorganic insulating material powder 5 and connected to the electrode lead wires 12 and 12 through the soters 11 and 11. As the electrode lead wires 12 and 12, so-called soft cables in which conductive wires such as copper are covered with a resin coating or the like can be used. Conductive wires 4 and 4 of the conductive fluid detector are connected to a measurement circuit via electrode lead wires 12 and 12.

  An end portion of the monitor pipe 8 that passes through substantially the center of the sheath 1 on the side opposite to the contact electrodes 6 and 6 side is derived from the sheath 1 and the inorganic insulating material powder 5, and a cylindrical reinforcing pipe is provided on the outer periphery of the derived end portion. 9 is fitted and fixed. A screw is cut on the outer peripheral portion of the tip of the reinforcing pipe 9, and a cylindrical cap 14 with a cap nut-like end face closed is screwed and attached thereto.

  A small diameter portion of a stepped cylindrical adapter case 10 is fitted to the end of the sheath 1 to which the conductive wires 4 and 4 are connected, on the opposite side to the contact electrodes 6 and 6 side, such as welding and brazing. It is fixed by means. In the adapter case 10, the connecting portions between the conductive wires 4 and 4 and the electrode lead wires 12 and 12 are accommodated. Further, the adapter case 10 is filled with an insulating material 13 such as an epoxy resin. Therefore, the connecting portions of the conductive wires 4 and 4 and the electrode lead wires 12 and 12 are embedded in the insulating material 13. Further, in the illustrated example, the joint between the monitor pipe 8 and the reinforcing pipe 9 is also embedded in the insulating material 13.

  The method of using the conductive fluid detector having such a configuration is basically the same as the conventional one described above. The contact electrodes 6 and 6 side is arranged at a place where the presence of the conductive fluid is to be detected, and the electrode lead wires 12 and 12 are connected to a measurement circuit so that the electrical resistance between the contact electrodes 6 and 6, the energization current value, etc. Observe changes. A conductive fluid is detected when a change occurs in the electrical resistance between the contact electrodes 6 and 6, the energization current value, and the like.

  As already described, the insulation of the conductive wires 4 and 4 is ensured by the sheath 1 and the inorganic insulating material powder 5 according to the present invention, and malfunction due to a short circuit is prevented. Furthermore, since the contact electrodes 6 and 6 are protected by the cover portion 2 and the end surface cover 7, it is possible to prevent malfunction due to a short circuit.

FIG. 3 shows another embodiment of the conductive fluid detector of the present invention. Also in this conductive fluid detector, a window 3 is provided on the distal end side of the sheath 1, the inorganic insulating material powder 5 is removed from a portion of the window 3 to form a hollow cover portion 2, and the end surface of the cover portion 2 is Closed by the end face cover 7. This structure is basically the same as the above-described embodiment.

In this conductive fluid detector, a four-core inorganic insulated cable in which four conductive wires 4 and 4 are accommodated in one sheath 1 is used. Lead ends of the conductive wires 4 and 4 are led out from the inorganic insulating material powder 5 in the cover portion 2 to be contact electrodes 6 and 6. Then, the two ends of the conductive wires 4 and 4 led out from the inorganic insulating material powder 5 are joined by means of brazing or the like, and are electrically connected. In these conductive fluid detectors, two conductive wires 4, 4 are assigned to each contact electrode 6, 6, so that even if there is a trouble such as disconnection of one conductive wire, it can be used. Higher reliability can be secured.

In the conductive fluid detector shown in FIG. 3, the monitor pipe 8 is provided substantially at the center of the sheath 1. However, in the conductive fluid detector shown in FIG. 4 shown as a comparative example, such a monitor pipe 8 is provided. Is not provided. The monitor pipe 8 has a fiberscope inserted therein to visually observe the tip of the conductive fluid detector, or a temperature measuring element such as a thermocouple, a pH electrode, or the like inserted therein to insert the fiberscope. Used to measure tip temperature and hydrogen concentration. It is necessary to provide a monitor pipe 8 for such observation and measurement.

  Since the conductive fluid detector according to the present invention can detect the presence of the conductive fluid with high reliability, the conductive fluid detector can be used to detect leakage of a liquid metal including, for example, a fast breeder reactor.

DESCRIPTION OF SYMBOLS 1 Sheath 2 Cover part 3 Opening part 4 Conductive wire 5 Insulating material powder 6 Contact electrode 7 End surface cover
8 monitor pipes

Claims (3)

Conductive fluid having contact electrodes (6) and (6) at the tip, and detecting the electrical continuity by the conductive fluid in contact with the contact electrodes (6) and (6) to detect the presence of the conductive fluid In the detector, the conductive wires (4) and (4) are accommodated in a metal tube-like sheath (1), and the inorganic insulating material powder (5) is placed between the conductive wires (4) and (4) and the sheath (1). ) Is used to cut the side surface near the tip of the sheath (1) into a window shape to form an opening (3), and inorganic insulation in the opening (3) The material powder (5) is led out to form a hollow cover part (2), and the conductive wires (4), (4) are formed in the cover part (2) from the end face of the inorganic insulating material powder (5). connected Sesshoku electrode (6) on, dissipate deriving (6), the cover part (2) Shisu opposite of (1) Conductive fluid detectors, characterized in that a monitoring pipe (8) which penetrates through the same sheath (1) over part. The conductive fluid detection according to claim 1, wherein the contact electrodes (6) and (6) are integrally formed with conductive wires (4) and (4) passing through the inside of the sheath (1). vessel. Two ends of the conductive wires (4) and (4) derived from the inorganic insulating material powder (5) in the cover portion (2) are joined to each other, and one contact electrode (6) and (6) 3. The conductive fluid detector according to claim 1, wherein two conductive wires (4) and (4) are assigned to each.

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