JP2019095392A - Level measurement device - Google Patents

Abstract

To provide a level measurement device capable of: achieving low cost with its simple structure and its simple manufacturing; and being placed corresponding flexibly to the shape or the size of a container.SOLUTION: A level measurement device 1 measures an upper surface height (water surface) of water (object to be measured) stored in a container 100. The level measurement device includes: a flexible circuit board 10 in which a plurality of electrode patterns 13-1-5 are formed on an insulation substrate 11; and one common electrode 30 placed at a position facing the electrode patterns 13-1-5 of the flexible circuit board 10. The flexible circuit board 10 is bonded on an outer peripheral surface of the container 100 so that heights of the individual electrode patterns 13-1-5 have different positions. Meanwhile, the common electrode 30 is placed at a position facing the individual electrode patters 13-1-5 inside the container 100.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a level measuring device that measures the level (upper surface height) of a measurement object such as liquid.

  Conventionally, as a level measuring device that detects the liquid level (liquid level) of liquid stored in a container such as a water tank, the water depth is measured from the water pressure obtained by a float type that detects the moving position of the float or a pressure sensor. There are pressure sensor types, etc. However, these level measuring devices have a problem that the structure is complicated and the cost can not be reduced.

  As a level measuring device which solves the said problem, there exists a level measuring device as described in FIG. 4 of FIG. 4, FIG. 5, etc. of patent document 1, for example. This level measuring instrument consists of seven pairs of seven pairs of electrode layers (E1a to E7a, E1b to E7b (Exb in FIG. 5)) on the outer surface of the cylindrical structure (30) made of an insulating material. Of the electrode pair (P1 to P7), and detecting the capacitance of the electrode pair (P1 to P7) which changes depending on the liquid entering the cavity (31) It measures the level.

Japanese Patent Application Laid-Open No. 11-311562

  However, not only the cylindrical structure (30) is necessary in the level measuring device shown in the above-mentioned Patent Document 1, but the electrode layers (E1a to E7a, E1b) are formed on the curved outer peripheral surface of the cylindrical structure (30). ~ E7b [Exb in FIG. 5] must be formed, and it can not be said that the structure and manufacture are simple. In addition, since the cylindrical structure (30) has a predetermined outer diameter size, it may be difficult to insert and install it, for example, in a narrow container.

  The present invention has been made in view of the above-described point, and the object thereof is to simplify the structure and manufacture, to achieve cost reduction, and to flexibly correspond to the shape and size of the container. It is in providing the level measuring instrument which can be done.

According to the present invention, in a level measuring instrument for measuring the upper surface height of a measurement object stored in a container, a circuit board having a plurality of electrode patterns formed on an insulating substrate and each electrode pattern of the circuit board are opposed. A common electrode disposed at a position, wherein the circuit board is disposed outside the container so that the heights of the respective electrode patterns are different, and the common electrode is disposed inside the container It is characterized in that it is installed at a position opposite to each of the electrode patterns.
As a measurement object, in addition to liquid such as water, it may be other than liquid such as soil.
According to the present invention, since the circuit board on which the electrode pattern is formed is disposed outside the container, the circuit board and the electrode pattern do not touch the object to be measured in the container, and therefore the durability is improved. be able to. On the other hand, the common electrode is immersed in the object to be measured, but since this is a common electrode, the degree of freedom in shape, structure, and material is high compared to the electrode pattern, and its durability is easily maintained high. Can.
In addition, since the circuit board may be installed outside the container and the common electrode may be installed in the container, the installation can be easily performed. Further, since only the common electrode is inserted into the container, the installation space is small, so that even a narrow container etc. can be easily installed, and can be installed flexibly corresponding to the shape and size of the container.

  The present invention is the level measuring instrument having the above-mentioned feature, wherein the common electrode also serves as a ground electrode by being grounded.

Further, the present invention is the level measuring instrument having the above-mentioned features, wherein the common electrode is formed only of a metal conductor.
By this, the common electrode can be configured by a metal conductor of a simple configuration. That is, since it is not necessary to form an electrode pattern etc. as a common electrode, for example, since it can comprise by a metal rod etc., not only a cost reduction can be achieved, an installation space can also be made small, and the installation can be performed easily.

  According to the level measuring instrument according to the present invention, the structure and the manufacturing can be simplified, the cost can be reduced, and the shape and the size of the container can be flexibly corresponded to the installation.

It is a schematic block diagram which shows the state which installed the level measuring device 1 in the container 100. FIG. FIG. 2 is a schematic view showing an electrical configuration of the level measuring instrument 1; FIG. 2 is a plan view of the flexible circuit board 10; It is a top view of flexible circuit board 10B.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration view showing a state in which a level measuring instrument 1 according to an embodiment of the present invention is installed in a container 100, FIG. 2 is a schematic view showing its electrical configuration, and FIG. FIG. 1 is a plan view of a circuit board (hereinafter referred to as “flexible circuit board”) 10. As shown in FIG. 1, the level measuring instrument 1 includes a flexible circuit board 10 in which a plurality of electrode patterns 13-1 to 5 are formed on an insulating substrate 11, and electrode patterns 13-1 to 5 of the flexible circuit board 10. And one common electrode 30 installed at a position opposed to the above, and the flexible circuit board 10 is the outside (peripheral surface) of the container 100, and the height of each of the electrode patterns 13-1 to 5 is The common electrodes 30 are disposed at different positions at predetermined intervals in the vertical direction, and the common electrodes 30 are disposed at positions facing the respective electrode patterns 13-1 to 5 in the container 100. In the following description, "upper" refers to the shallow side of the water depth of the container 100, and "lower" refers to the deep side of the water depth of the container 100.

  In this example, the container 100 is a container (water tank) whose upper surface is opened, and water (liquid, measurement object) 150 is stored therein to a predetermined water level.

  The flexible circuit board 10 has a plurality of (five in this example) electrode patterns 13-1 to 5 above and below it on one surface of an insulating substrate 11 made of a substantially rectangular and longitudinally long flexible synthetic resin film. It is configured to be formed in one row at predetermined intervals in the direction (vertical direction). Each of the electrode patterns 13-1 to 13-5 has the same rectangular shape, and is formed by screen-printing, for example, a conductive paste on the insulating substrate 11 with a gap of the same interval. A strip-like lead-out portion 21 is connected to a predetermined position on the outer periphery of the insulating substrate 11, and a water level detection means 23 is connected to the other end side of the lead-out portion 21. The water level detection means 23 may be formed on the same film as the insulating substrate 11. A circuit pattern 15 is connected to each of the electrode patterns 13-1 to 5, and these circuit patterns 15 are connected to the water level detection means 23 through the lead-out portion 21.

  The water level detection means 23 is a circuit that detects the electric capacity between each of the electrode patterns 13-1 to 5 and the common electrode 30 to detect the water level of the water 150 in the container 100. That is, the water level detection means 23 measures the electric capacity between each of the electrode patterns 13-1 to 5 and the common electrode 30, respectively, and when there is water 150 between them or not (in addition, in the electrode pattern 13). It is a circuit which detects the water level (liquid level) in the container 100 from the difference in the electrostatic capacitance which arises in which position the water 150 exists. As shown in FIG. 2, the water level detection means 23 includes capacitance detection units 231-1 to 5-5 connecting the circuit patterns 15 drawn from the electrode patterns 13-1 to 5 and capacitance detection units 231-1 to 5-5. And a measured water level output unit 233 which receives a signal of the detected capacitance value and detects and outputs a water level.

  In this embodiment, the flexible circuit board 10 is attached to the outer surface of the container 100. However, since the flexible circuit board 10 has flexibility, the outer surface shape of the container 100 is curved, or Even if it is bent, it can easily follow it, bend and bend, and can be attached closely to the outer surface.

  The common electrode 30 is constituted by a single linear elongated rod-like body having conductivity, and more specifically, is constituted by a metal rod such as iron or brass. That is, it is formed only of a metal conductor. The common electrode 30 has a length at least facing all the electrode patterns 13-1 to 5 of the flexible circuit board 10. Further, one end of the common electrode 30 is grounded by the conducting wire 31. That is, the common electrode 30 doubles as a ground electrode. The conducting wire 31 may be made of the same metal rod as that of the common electrode 30, and one end thereof may be directly grounded. Such a configuration further simplifies the structure. The common electrode 30 is installed at a position facing the portion (portion of each of the electrode patterns 13-1 to 5) in the container 100 to which the circuit board 10 is attached. At this time, the common electrode 30 is installed at the same distance from each of the electrode patterns 13-1 to 5. As a result, the capacitances between the electrode patterns 13-1 to 13-5 and the common electrode 30 become the same as long as the medium filling the gap therebetween is the same.

  In the level measuring instrument 1 having the above configuration, for example, if the water level in the container 100 is at the level L1 shown in FIG. 1, water 150 is interposed between the electrode patterns 13-1 to 13 and the common electrode 30. Air is interposed between the electrode patterns 13-4 and 5 and the common electrode 30. Therefore, the capacitances between the electrode patterns 13-1 to 13-3 and the common electrode 30, and the capacitances between the electrode patterns 13-4 and 5 and the common electrode 30 are largely different. For this reason, the measured water level output means 233 can detect the water level in the container 100 by comparing the capacitances of the electrode patterns 13-1 to 5.

  As described above, according to the level measuring instrument 1, the flexible circuit board 10 on which the electrode patterns 13-1 to 5 are formed is installed outside the container 100, so the flexible circuit board 10 and the electrode pattern 13- 1 to 5 do not touch the water (solution, medium, object to be measured) 150 in the container 100, so that the durability can be improved. That is, deterioration (corrosion, ion exchange, etc.) of the electrode patterns 13-1 to 5 does not occur. Moreover, since the electrode patterns 13-1 to 5 are not immersed in the water 150, the measured value is stabilized. On the other hand, although the common electrode 30 is immersed in the water 150, since this is the common electrode 30, it has a high degree of freedom in shape, structure, and material as compared with the electrode patterns 13-1 to 5, and its durability easily It can maintain high sex.

  In addition, since the flexible circuit board 10 may be installed outside the container 100 and the common electrode 30 may be installed in the container 100, the installation can be easily performed. Further, since only the common electrode 30 is inserted into the container 100, the installation space is small, so that even a narrow container 100 or the like can be easily installed, and can be installed flexibly corresponding to the shape and size of the container 100. .

  By the way, in the above description, the detection of the water level in the container 100 is performed so as to digitally detect whether the electrode pattern 13 is above or below the water surface in units of the electrode patterns 13-1 to 5. In the example described above, the detection of the water level can also be performed in an analog manner by detecting a change in capacitance in any one of the electrode patterns 13. That is, for example, when the water surface in the container 100 is at the level L2 shown in FIG. 1, that is, in the middle of the electrode pattern 13-2, its electrostatic capacity is an electrode pattern in which the water 150 is all interposed. Unlike the capacitance of 13-1 and the capacitance of the electrode patterns 13-3 to 5 in which air intervenes in all, the capacitance is an intermediate capacitance therebetween. Moreover, the capacitance changes in accordance with the fluctuation of the water surface. Therefore, the position of the water surface in the electrode pattern 13-2 in which the water surface is halfway can be detected in an analog manner.

  FIG. 4 is a plan view of a flexible circuit board 10B according to another embodiment of the present invention. In the flexible circuit board 10B shown in the figure, the same or corresponding parts as in the flexible circuit board 10 according to the embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals (however, the suffix "B" is attached to each reference numeral). Attached). The items other than the items described below are the same as those in the embodiment shown in FIGS.

  The flexible circuit board 10B differs from the flexible circuit board 10 in the shapes of the electrode patterns 13B-1 to -5. That is, all of the electrode patterns 13B-1 to 5-5 have the same shape, and the upper side and the lower side are formed in a parallelogram in which the upper side and the lower side are inclined with respect to the water surface. And between the electrode patterns 13B adjacent to the upper and lower sides, a position where the opposite sides (ie, the upper side of the lower electrode pattern 13B and the lower side of the upper electrode pattern 13B) intersect with the same horizontal plane It is configured to be

  According to this structure, even when the water surface is located in the space between the electrode patterns 13B adjacent to the upper and lower sides, the electrostatic capacitance of the electrode patterns 13B on the upper and lower sides is changed by the movement of the water surface. Therefore, all water level positions can be detected in an analog manner.

  In the above embodiment, a metal rod is used as the common electrode 30. However, the present invention is not limited to this. For example, a ground pattern is formed on a band-like hard or flexible insulating substrate The point is that any configuration may be used as long as it is a common electrode (one through which electricity passes) installed at a position facing each of the electrode patterns 13-1 to 5 of the flexible circuit board 10. . Of course, when the common electrode 30 is formed of only a metal conductor, for example, a metal rod, not only significant cost reduction can be achieved as compared with the configuration in which an electrode pattern or the like is formed on the insulating substrate It can be easily made smaller by making it a thin rod-like body, and since it is also rigid, its installation can be easily performed.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications may be made within the scope of the claims and the technical idea described in the specification and the drawings. It is possible. It is within the scope of the technical idea of the present invention as far as the functions and effects of the present invention can be obtained regardless of any shape, structure or material not described in the specification and drawings directly. For example, in the above embodiment, a flexible circuit board is used as the circuit board, but in some cases, a hard circuit board may be used. Moreover, in the said embodiment, although the measurement object was used as water, various solutions other than water may be used, and also soil etc. may be sufficient other than a solution. The point is that any measurement object can be used as long as it can detect capacitance.

  The container used in the present invention may be various small containers or a large container such as a reservoir. Further, in the above embodiment, each electrode pattern is configured to be vertically positioned in the vertical direction, but the present invention is not limited to this, and the electrode patterns may be installed to be different in height in the diagonal direction. Further, the intervals for providing the plurality of electrode patterns do not have to be the same, and the plurality of electrode patterns may be arranged at different separation distances. The point is that as long as the electrode patterns are disposed at different heights, they may be disposed in any manner.

  In addition, the embodiments described above and shown in the respective drawings can be combined with each other unless the purpose, configuration, and the like are consistent. In addition, even if a part of the above description and the contents of the description of each figure can be an independent embodiment, the embodiment of the present invention is an embodiment combining the above description and each figure. It is not limited to

1 Level measuring instrument 10 Flexible circuit board (circuit board)
11 Insulating substrate 13-1-5 electrode pattern 30 common electrode 100 container 150 water (object to be measured)

Claims (3)

In a level measuring instrument for measuring the top surface height of a measurement object stored in a container,
A circuit board having a plurality of electrode patterns formed on an insulating substrate;
A common electrode disposed at a position opposed to each electrode pattern of the circuit board;
Have
The circuit board is installed outside the container so that the heights of the electrode patterns are different from each other,
A level measuring instrument characterized in that the common electrode is disposed at a position facing the respective electrode patterns inside the container. The level measuring instrument according to claim 1, wherein
The level measuring instrument, wherein the common electrode doubles as a ground electrode by being grounded. The level measuring instrument according to claim 1 or 2, wherein
The level measuring instrument, wherein the common electrode is formed only of a metal conductor.

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