JP2020008343A - Liquid level sensor - Google Patents

Abstract

To provide a liquid level sensor with which it is possible to simplify means for detecting static capacitance.SOLUTION: The liquid level sensor comprises a conductive detection member 10 for forming static capacitance between a water 2 that gradually increases in a liquid retention container 1 and itself, and static capacitance detection means 20 of self-capacitance type that outputs a detection value in accordance with a change of static capacitance, the conductive detection member 10 being connected to the static capacitance detection means 20 by integrally rearranging a plurality of detection units, with the plurality of detection units arrayed in the height direction of the liquid retention container 1. One length of conductive wire 11 of the conductive detection member 10 is connected to the static capacitance detection means 20 and, furthermore, the conductive wire 11 is processed into a plurality of bend detection parts 12 and connection detection parts 13 and since the plurality of these bend detection parts 12 and connection detection parts 13 are integral as a detection unit, the number of terminals of the static capacitance detection means 20 can be reduced to one. Therefore, it can be expected that the configuration of the static capacitance detection means 20 is simplified.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid level sensor that measures liquid levels of various liquids by using a capacitance value.

  There are various types of water level sensors, and one of them is a capacitance type that can be used regardless of the non-conductivity or conductivity of the liquid. Although not shown, the capacitance type water level sensor includes a plurality of detection electrodes for detecting a water level, and detection means connected to the plurality of detection electrodes, and the plurality of detection electrodes are arranged like a slider. (See Patent Document 1).

US 9,488,513

  The conventional water level sensor is configured as described above, and although suppression of power and the like can be expected, since it is a configuration that captures the detection values of a plurality of detection electrodes, the number of terminals of the detection means increases, and as a result, the configuration of the detection means Is complicated.

  The present invention has been made in view of the above, and an object of the present invention is to provide a liquid level sensor that can simplify means for detecting capacitance.

In the present invention, in order to solve the above problems, a conductive detection member that forms a capacitance between a liquid that increases and decreases in a liquid reservoir, and a capacitance that outputs a detection value according to a change in the capacitance Detection means,
The conduction detecting member is characterized in that a plurality of detecting sections are integrally arranged and connected to the capacitance detecting means, and the plurality of detecting sections are arranged in the height direction.

Note that the conductivity detection member includes a conductive wire connected to the capacitance detection means facing the wall of the liquid storage body,
The conductive wire includes a plurality of bending detection units arranged at predetermined intervals in the height direction of the liquid storage body, and includes a connection detection unit that connects the plurality of bending detection units,
Each of the bend detecting portions can be formed by a conductive wire being wound around a liquid storage body and approaching the same.

In addition, the conductivity detection member includes a conductive wire connected to the capacitance detection unit facing the wall of the liquid storage body,
The conductive wire includes a plurality of bending detection units arranged at predetermined intervals in the height direction of the liquid storage body, and includes a connection detection unit that connects the plurality of bending detection units,
Each of the bending detecting portions may include an extended portion extending laterally from an end of the connection detecting portion, and a folded portion that is folded substantially in a bellows shape from the end of the extended portion toward the connection detecting portion.

Further, the conductivity detection member includes a conductive pattern connected to the capacitance detection unit facing the wall of the liquid storage body,
The conductive pattern includes a detection trunk piece that is connected to the capacitance detection means in the height direction of the liquid storage body, and includes a plurality of detection pieces extending laterally from one side of the detection trunk piece, The plurality of detection pieces can be arranged at predetermined intervals in the height direction of the liquid storage body.

Further, the conductivity detection member includes a conductive pattern connected to the capacitance detection means facing the wall of the liquid storage body,
The conductive pattern includes a detection trunk connected to the capacitance detecting means in the height direction of the liquid storage body, and a plurality of detection fragments extending laterally from both sides of the detection trunk. A plurality of detection pieces can be arranged at predetermined intervals in the height direction of the liquid storage body.

  Further, the liquid storage body includes a first liquid storage body that stores liquid, and a second liquid storage body that fits into the first liquid storage body from outside without substantially any gap. The conductive detection member can be attached to any one of the peripheral walls of the liquid reservoir.

  Here, the liquid reservoir in the claims is not particularly limited to transparent, opaque, and translucent. The liquid reservoir includes at least various tanks, containers, bottles, bags, bathtubs, and the like. Further, the liquid includes at least water, pure water, body fluid, paint, mucus, drug solution, solution, and the like. This increase or decrease in liquid includes an increase or decrease in liquid. The conductive detection member may be attached to the wall of the liquid storage body, specifically, at least a part of the inner surface or outer surface of the peripheral wall by a method such as winding, sticking, bonding, or sticking, and may be in contact with the liquid. , Need not be in contact.

  The conductive detection member includes a bendable resin sheet and a conductive wire connected to the capacitance detecting means, and any one of the resin sheet and the conductive wire can be directly attached to the wall of the liquid storage body. It also includes a bendable resin sheet and a conductive pattern connected to the capacitance detecting means, and any one of the resin sheet and the conductive pattern can be directly attached to the wall of the liquid storage body.

  According to the present invention, the conductivity detection member is connected to the capacitance detection means, and the plurality of detection units of the conductivity detection member are not separate structures but are integrated structures, so that the detection units can be substantially unitized. In addition, the number of terminals of the capacitance detecting means can be reduced.

  According to the present invention, since the conductive detection member integrally includes the plurality of detection units and the plurality of detection units are arranged in the height direction, it is possible to simplify the means for detecting the capacitance. There is an effect that can be.

  According to the second aspect of the present invention, since one conductive wire of the conductive detecting member is connected to the capacitance detecting means, and the plurality of bending detecting portions and the connection detecting portion of the conductive wire are integrated, The number of terminals of the capacitance detecting means can be reduced. Therefore, simplification of the configuration of the capacitance detecting means can be expected. In addition, since the bending detecting section is formed by winding the conductive wire around the liquid reservoir substantially in a coil, the change in capacitance can be detected with high accuracy, and the conductive wire is prevented from being displaced in the vertical direction. You can also.

  According to the third aspect of the invention, it is possible to simplify the configuration of the capacitance detecting means and diversify the shape of the conductive wire. In addition, since the liquid level can be detected by attaching a conductive wire to a part of the wall of the liquid storage body, it is not necessary to attach a conductive wire to the entire circumference of the wall of the liquid storage body, thereby improving the handleability. Becomes possible.

According to the fourth aspect of the present invention, since it is not necessary to wind the conductive wire around the wall of the liquid storage body over time, simplification, speeding up, and facilitation of the manufacturing operation of the liquid level sensor can be expected.
According to the fifth aspect of the present invention, since it is not necessary to wind a conductive wire around the wall of the liquid storage body, it is possible to simplify, speed up, and facilitate the manufacturing operation of the liquid level sensor. Further, since the number of detection pieces of the conductive pattern is increased, the area of the detection pieces facing the liquid increases, and the liquid level can be detected with high accuracy.

It is a front explanatory view showing typically the embodiment of the liquid level sensor concerning the present invention. It is explanatory drawing which shows typically the state which hold | maintained the liquid storage container in the sky of the desk in embodiment of the liquid level sensor which concerns on this invention. It is a graph which shows the Raw count in embodiment of the liquid level sensor which concerns on this invention typically. It is a perspective explanatory view showing typically the operation principle in an embodiment of a liquid level sensor concerning the present invention. It is explanatory drawing which shows typically the state which hold | maintained the liquid storage container in 2nd Embodiment of the liquid level sensor which concerns on this invention above a metal member. It is a graph which shows Raw count in a 2nd embodiment of the liquid level sensor concerning the present invention typically. It is explanatory drawing which shows typically the state which kept the liquid storage container low above the metal member in 3rd Embodiment of the liquid level sensor which concerns on this invention. It is a graph which shows Raw count in a 3rd embodiment of a liquid level sensor concerning the present invention typically. It is explanatory drawing which shows typically the conductive wire in 4th Embodiment of the liquid level sensor which concerns on this invention. It is explanatory drawing which shows 5th Embodiment of the liquid level sensor which concerns on this invention typically. It is explanatory drawing which shows 6th Embodiment of the liquid level sensor which concerns on this invention typically. It is explanatory drawing which shows typically the state which hold | maintained the liquid storage container in 6th Embodiment of the liquid level sensor which concerns on this invention above a desk. It is a graph which shows Raw count in the 6th embodiment of the liquid level sensor concerning the present invention typically. It is a plane explanatory view showing a 7th embodiment of a liquid level sensor concerning the present invention.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1 to FIG. A conductive detection member that forms a capacitance between the conductive detection member and a self-capacitance type capacitance detection unit that outputs a RAW count that is a detection value according to a change in the capacitance; Is provided with a plurality of detection units integrally arranged, and the plurality of detection units are arranged in the height direction of the liquid storage container 1, and detects a change in water level as a change in capacitance.

  As shown in FIGS. 1 and 2, the liquid storage container 1 is not particularly limited, but is formed of, for example, a substantially test tube-shaped bottomed cylindrical shape or a bottomed cylindrical shape by a fluororesin, and is formed of a liquid. Store some water 2 A water supply pipe (not shown) is connected to the liquid storage container 1, and water 2 gradually increases in the liquid storage container 1 by the water supply action of the water supply pipe.

  As shown in FIGS. 1 and 2, the conductivity detecting member 10 is formed of a single conductive wire 11 wound around the peripheral wall of the liquid storage container 1 and connected to the capacitance detecting means 20. The conductive wire 11 is not particularly limited, but is made of, for example, a coated copper wire or an enamel-coated copper wire covered with a vinyl chloride resin. It is directly wound from the direction upward, covered with a transparent adhesive tape or the like, positioned and fixed, and the lower end is electrically connected to the capacitance detecting means 20.

  The conductive wires 11 include a plurality of bend detection units (four in the present embodiment) 12 arranged at predetermined equal intervals in the height direction of the liquid storage container 1, in other words, in the vertical direction, and the plurality of bend detection units. A plurality of connection detectors (four in this embodiment) 13 for vertically connecting the parts 12 are integrally provided, and the plurality of bending detectors 12 and the connection detectors 13 serve as detectors in the liquid storage container 1. And the water 2 of the other.

  When measuring the increasing water level between the plurality of bend detection units 12 and between the uppermost bend detection unit 12 and the upper end of the liquid storage container 1, for example, a level 1, level 2, level 3, and level 4 (see FIG. 2). Each of the bend detecting units 12 is formed by winding the conductive wire 11 tightly around the lower part, near the center, and above the liquid storage container 1, and bringing the coiled conductive wire 11 into close proximity.

  The capacitance detecting means 20 includes, for example, a microcontroller or the like. A predetermined history and the like are stored in the RAM, a predetermined program is stored in the ROM, and the predetermined program is rewritten by the controller as necessary. Can be The microcontroller is not particularly limited, but includes, for example, a CPU, a RAM, a ROM, an I / O block, and the like, and a Cypress PSoC that can design digital and analog circuits separately in the IC. (A registered trademark of Cypress Semiconductor Corporation) or the like is used. The capacitance detecting means 20 is connected to a computer device (not shown), a monitor, various alarms, and the like, as necessary, in addition to the end of the conductive wire 11 to facilitate measurement and monitoring.

  Such a capacitance detecting means 20 functions as a computer when the CPU reads a predetermined program stored in the ROM using the RAM area as a work area, thereby realizing a predetermined function as a computer and contributing to water level measurement. That is, the capacitance detecting means 20 has a function of converting a change in capacitance between the water 2 and the conductive wire 11 into a Raw count (detected value) to detect the change, and a function of recording the detected Raw count. And realize.

  Next, the principle of measuring the water level by the liquid level sensor will be described. For example, as shown in FIG. 1, a conductive wire 11 of a conductive detection member 10, specifically a wire diameter of 0.55 mm, is formed on the outer surface of a peripheral wall of a liquid storage container 1 formed of a fluororesin into a test tube shape having an outer diameter of 12 mm. An enamel-coated copper wire is wound around to form a liquid level sensor, and the end of the conductive wire 11 of the liquid level sensor is connected to the capacitance detecting means 20, and the empty liquid storage container 1 is set as shown in FIG. After the table 30 is held at a height of 47 mm above the desk 30, the Raw count is measured and recorded by the capacitance detecting means 20.

  Next, the liquid storage container 1 is filled with water 2 and its water level is adjusted to level 1, and the RAW count is measured and recorded by the capacitance detecting means 20. Thereafter, the liquid storage container 1 is filled with water 2 in a stepwise manner, and the water level is sequentially adjusted to level 2, level 3, and level 4, and the RAW count is measured and recorded by the capacitance detecting means 20 every time the water level is adjusted. I do. When these Raw counts are represented in a graph, as shown in FIG. 3, the raw count of level 1 is about 6150, the raw count of level 4 is about 6370, and the ratio thereof is + 3.57%. If measured, the water level can be continuously detected.

  Next, the operation principle of the liquid level sensor will be described. The operation principle of the liquid level sensor is the same as that of a normal touch switch of the self-capacitance type. In a normal touch switch of the self-capacitance type, a conductive detection electrode connected to an input terminal of the capacitance detecting means 20 is connected between a GND of the capacitance detecting means 20 through a conductive material or a dielectric around the conductive detecting electrode. To form a capacitance. The capacitance detection means 20 using the PSoC detects the capacitance and outputs a Raw count proportional to the capacitance.

  Here, the fact that the human body touches the detection electrode means that, when the human body is not touching, the human body having a higher relative dielectric constant than air touches the detection electrode that air has touched. The capacitance between the two increases. For this reason, the RAW count becomes larger when the human body touches, as compared with the case where the human body does not touch, so that a change in the count value can be interpreted as the human body touching. Also, the larger the area of the human body touching the detection electrode, the larger the change in the Raw count. This is because the capacitance is proportional to the facing area as shown in the equation (1) with the capacitor in FIG.

In FIG. 4, the capacitance C of the capacitor is C [F], the dielectric constant of the dielectric is ε [F / m], the area of the opposing electrode plates is S [m ² ], Assuming that the distance between the opposing electrode plates is d [m],
C = ε _r ε ₀ S / d (Equation 1)
Where ε _r = dielectric constant
ε ₀ = 8.85418781762 × 10 ⁻¹² (dielectric constant in vacuum)

  The liquid level sensor according to the present embodiment will be described based on the above description. When the liquid 2 is filled in the liquid storage container 1 and the water 2 faces the conductive wire 11, the conductive wire 11, specifically, the bending detecting unit 12 is used. The connection detection unit 13 functions as a detection electrode similarly to the detection electrode of the touch switch. At this time, the water 2 in the liquid storage container 1 becomes an object to be detected like the human body of the touch switch, and thus causes a change in the Raw count.

  When the water 2 is further filled in the liquid storage container 1 and the amount of water increases, the facing area of the water 2 in the liquid storage container 1 and the bending detection unit 12 and the connection detection unit 13 of the conductive wire 11 increases. Accordingly, the amount of change in the Raw count increases. That is, the RAW count increases as the liquid storage container 1 is filled with the water 2 and the amount of water increases, as compared with the case where the liquid storage container 1 is empty. The above is the operation principle of the liquid level sensor.

  According to the above configuration, one conductive wire 11 of the conductive detection member 10 is connected to the capacitance detecting means 20, and the conductive wire 11 is processed into a plurality of bending detection units 12 and connection detection units 13. Since the plurality of bending detection units 12 and the connection detection unit 13 are integrated, the number of terminals of the capacitance detection unit 20 can be one. Therefore, simplification of the configuration of the capacitance detecting means 20 can be greatly expected.

  Further, since the bending detecting unit 12 is formed by winding the conductive wire 11 around the liquid storage container 1, a change in capacitance can be detected with high accuracy. In addition, since the conductive wire 11 is wound tightly around the liquid storage container 1, the displacement of the conductive wire 11 in the vertical direction can be effectively prevented. Further, since the measurement is performed by using the capacitance, malfunctions due to adhesion of dirt on the surface of the liquid level sensor are reduced, and it is possible to reduce the influence of dust, rain, and the like. Furthermore, if the dielectric constant around the conductivity detection member 10 is reduced, the detection capability of the conductivity detection member 10 can be improved.

  Next, FIG. 5 shows a second embodiment of the present invention. In this case, a metal member 31 is arranged on a desk 30 located below the liquid storage container 1 so that a capacitance detecting means 20 is provided. Is connected to GND.

  Although the metal member 31 is not particularly limited, for example, a thin aluminum foil or the like is used, and the height up to the lower end of the liquid storage container 1 is the same as the above-described embodiment (for example, 47 mm). Is set. The other parts are the same as those in the above-described embodiment, and a description thereof will be omitted.

  In the above configuration, the empty liquid storage container 1 is held above the metal member 31 as shown in FIG. 5, and after the Raw count is measured and recorded by the capacitance detecting means 20, the water 2 is poured into the liquid storage container 1. After filling, the water level is adjusted to level 1 and the Raw count is measured and recorded by the capacitance detecting means 20. After that, the liquid 2 is gradually filled into the liquid storage container 1 and the water level is sequentially adjusted to level 2, level 3, and level 4, and the RAW count is measured by the capacitance detecting means 20 every time the water level is adjusted. Record.

  When these raw counts are represented in a graph, as shown in FIG. 6, the raw count of level 1 is about 6250, the raw count of level 4 is about 6470, and the ratio thereof is + 3.52%. The measurement enables the water level to be detected. Further, the Raw count can be increased by disposing the metal member 31.

  Next, FIG. 7 shows a third embodiment of the present invention. In this case, a metal member 31 is arranged on a desk 30 located below the liquid storage container 1 and a capacitance detecting means 20 is provided. And the height from the metal member 31 to the lower end of the liquid storage container 1 is set lower (for example, 16 mm) than in the above embodiment. The other parts are the same as those in the above-described embodiment, and a description thereof will be omitted.

  In the above configuration, the empty liquid storage container 1 is held above the metal member 31 as shown in FIG. 7, and after the Raw count is measured and recorded by the capacitance detecting means 20, the water 2 is poured into the liquid storage container 1. After filling, the water level is adjusted to level 1 and the Raw count is measured and recorded by the capacitance detecting means 20. After that, the liquid 2 is gradually filled into the liquid storage container 1 and the water level is sequentially adjusted to level 2, level 3, and level 4, and the RAW count is measured by the capacitance detecting means 20 every time the water level is adjusted. Record.

  When these Raw counts are represented in a graph, as shown in FIG. 8, the Raw count of level 1 is about 6380, the raw count of level 4 is about 6590, and the ratio thereof is + 3.29%. The measurement enables the water level to be detected. Further, since the height from the metal member 31 to the lower end of the liquid storage container 1 is adjusted to be low, the value of the Raw count can be further increased.

  Next, FIG. 9 shows a fourth embodiment of the present invention. In this case, the conductivity detection member 10 is attached to a part of the wall of the liquid storage Is connected to one conductive line 11.

  The conductive wire 11 includes a plurality of bend detection units 12A arranged at predetermined intervals in the height direction of the liquid storage container 1, and a plurality of connection detection units 13 that vertically connect the plurality of bend detection units 12A. The liquid storage container 1 is integrally provided, and the inner or outer surface of the peripheral wall of the liquid storage container 1 is covered with a transparent adhesive tape or the like, and is positioned and fixed. Each of the bending detecting portions 12A includes an extended portion 14 extending horizontally from an end of the connection detecting portion 13 in a horizontal direction, and a folded portion which is continuously folded from the end of the extended portion 14 in the direction of the connection detecting portion 13 in a substantially bellows shape. 15 and is integrally formed. The other parts are the same as those in the above-described embodiment, and a description thereof will be omitted.

  It is apparent that the same effects as those of the above embodiment can be expected in this embodiment, and that the shape of the conductive wire 11 can be diversified. In addition, since the conductive wire 11 can be attached to a part of the peripheral wall of the liquid storage container 1, it is not necessary to attach the conductive wire 11 to the entire peripheral wall of the liquid storage container 1, and the handling of the conductive wire 11 is greatly improved. Can be improved.

  Next, FIG. 10 shows a fifth embodiment of the present invention. In this case, a conductive sheet 16 is attached to a wall of the liquid storage container 1, And the conductive pattern 17 facing the wall of the liquid storage container 1, and the conductive pattern 17 is connected to the capacitance detecting means 20.

  The resin sheet 16 is not particularly limited, but may be, for example, polyester, polypropylene, polyethylene, polyethylene terephthalate, polycarbonate, polyamide, polyimide, phenol resin, glass fiber impregnated epoxy resin, ABS resin, acrylic resin, or these. Made of an alloy insulating sheet. After the formation of the conductive pattern 17, the resin sheet 16 is cut into a substantially comb-like planar shape, and is adhered to the outer surface of the peripheral wall of the liquid storage container 1 via an adhesive tape or the like.

  The conductive pattern 17 is linearly oriented in the height direction of the liquid storage container 1 and has an elongated detection trunk piece 18 whose end is connected to the capacitance detection means 20. A plurality of detection pieces 19 each extending in the horizontal and horizontal directions are integrally provided, and are printed on the resin sheet 16 in a substantially comb-shaped plane. The conductive pattern 17 is screened using a conductive material such as gold, silver, copper, nickel, chromium, aluminum, brass, a laminated member or alloy thereof, a conductive paste, carbon nanotube, carbon nanofiber, or a conductive polymer. Printed.

  The detection trunk piece 18 and the plurality of detection pieces 19 form a capacitance between the detection trunk piece 18 and the water 2 in the liquid storage container 1 as a detection unit. The plurality of detection pieces 19 are arranged at predetermined intervals in the height direction of the liquid storage container 1, and each detection piece 19 is formed in a flat rectangular shape that is thicker than the detection trunk piece 18.

  In the case of manufacturing such a liquid level sensor, a conductive material for the conductive pattern 17 is screen-printed on the resin sheet 16 in a substantially comb-shaped plane and dried and cured to form the conductive pattern 17. The resin sheet 16 may be cut along the peripheral edge portion 17 and then the resin sheet 16 may be adhered to the outer surface of the peripheral wall of the liquid storage container 1 via an adhesive tape or the like. The other parts are the same as those in the above-described embodiment, and a description thereof will be omitted.

  In this embodiment, the same operation and effect as the above embodiment can be expected, and the conductive pattern 17 is divided into a detection trunk piece 18 and a plurality of detection pieces 19, and these detection trunk pieces 18 and the plurality of detection pieces 19 are integrated. Therefore, the detection part can be unified. Therefore, the number of terminals of the capacitance detecting means 20 can be reduced to one, and the configuration of the capacitance detecting means 20 can be simplified. Also, since it is not necessary to carefully wind up one conductive wire 11 around the peripheral wall of the liquid storage container 1 over time, simplification, speeding up, and simplification of the manufacturing operation of the liquid level sensor can be greatly expected.

  Further, since the conductive pattern 17 is screen-printed, the plurality of detection pieces 19 can be formed uniformly and with high accuracy, and excellent mass productivity can be expected. In addition, according to the screen printing method, the conductive material is supplied and printed according to the principle of "first-in first-out" of the conductive material, so that a conductive material having a higher viscosity can be used continuously than other printing methods. Becomes Further, if a plurality of conductive patterns 17 are screen-printed on the resin sheet 16 and the plurality of conductive patterns 17 are engaged with each other, a useless area on the resin sheet 16 is reduced, and the resin sheet 16 can be efficiently used. Becomes possible.

  Next, FIG. 11 to FIG. 13 show a sixth embodiment of the present invention. In this case, the conductive detection member 10 is provided with a resin sheet 16 adhered to the wall of the liquid storage container 1, The conductive sheet 17 is formed on the resin sheet 16 by screen printing or the like, and is formed from the conductive pattern 17 facing the wall of the liquid storage container 1. The pattern of the conductive pattern 17 is changed and connected to the capacitance detecting means 20. .

  The conductive pattern 17 is linearly oriented in the height direction of the liquid storage container 1 and has an elongated detection trunk piece 18 whose end is connected to the capacitance detection means 20. A plurality of detection pieces 19 each extending in the horizontal direction are integrally provided, and a plurality of T-characters are printed on the resin sheet 16 in a form of being arranged in a vertical line.

  The detection trunk piece 18 and the plurality of detection pieces 19 form a capacitance between the detection trunk piece 18 and the water 2 in the liquid storage container 1 as a detection unit. The plurality of detection pieces 19 are arranged at predetermined intervals in the height direction of the liquid storage container 1, and each detection piece 19 is formed in a flat rectangular shape that is thicker than the detection trunk piece 18. When measuring the water level of the increasing water 2 between the plurality of detection pieces 19, the water level is used as, for example, level 1, level 2, level 3, and level 4 from below to above (see FIG. 12). . The other parts are the same as those in the above-described embodiment, and a description thereof will be omitted.

  In the above configuration, the empty liquid storage container 1 is held above the desk 30, and the Raw count is measured and recorded by the capacitance detecting means 20, and then the liquid storage container 1 is filled with water 2 and the water level is set to the level. It is adjusted to 1 and the Raw count is measured and recorded by the capacitance detecting means 20. Then, the liquid 2 is gradually filled into the liquid storage container 1 and the water level is sequentially adjusted to level 2, level 3, and level 4, and the RAW count is measured and recorded by the capacitance detecting means 20 every time the water level is adjusted. I do. When these raw counts are represented in a graph, as shown in FIG. 13, the raw count of level 1 is about 7885, the raw count of level 4 is about 7945, and the ratio thereof is + 0.76%. The measurement enables the water level to be detected.

  In this embodiment, the same operation and effect as the above embodiment can be expected, and the conductive pattern 17 is divided into a detection trunk piece 18 and a plurality of detection pieces 19, and these detection trunk pieces 18 and the plurality of detection pieces 19 are integrated. Therefore, the detection portion can be unified, and the number of terminals of the capacitance detection means 20 can be reduced to one. Therefore, the configuration of the capacitance detecting means 20 can be simplified. Further, since the number of the plurality of detecting pieces 19 is larger than that in the above embodiment, the area of the detecting pieces 19 facing the water 2 increases, and the water level can be detected with high accuracy.

  Next, FIG. 14 shows a seventh embodiment of the present invention. In this case, the liquid storage container 1 is divided into a first liquid storage container 3 for storing water 2 and a first liquid storage container 3. The second liquid storage container 4 is fitted into the container 3 from the outside without any gap and protected, and is divided into two parts. The conductive liquid is applied to the outer surface of the peripheral wall of the first liquid storage container 3 or the inner surface of the peripheral wall of the second liquid storage container 4. The detection member 10 is attached.

The conductivity detecting member 10 in this case is not particularly limited, and may be a conductive wire type or a conductive pattern type. The other parts are the same as those in the above-described embodiment, and a description thereof will be omitted.
In this embodiment, the same operation and effect as those in the above embodiment can be expected, and furthermore, diversification of the configuration of the liquid storage container 1 and the liquid level sensor can be expected.

  Note that the conductivity detection member 10 of the above embodiment can detect a change in water level as a change in capacitance, even if there is an object with a high dielectric constant in the surroundings. In this case, it is desirable to mount the device at a distance from an object having a high dielectric constant. In the above-described embodiment, the number of the plurality of bending detectors 12 of the conductive wire 11 is four, but the number is not limited to this and may be increased or decreased as needed.

  In addition, the number of the plurality of detection pieces 19 of the conductive pattern 17 is also four, but the number is not limited thereto, and may be increased or decreased as needed. Further, a conductive detection member 10 for forming a capacitance between the water 2 that gradually decreases in the liquid storage container 1 and a self-capacitance type capacitance for outputting a detection value according to a change in the capacitance. A liquid level sensor including the detection unit 20 may be used. In this case, the Raw count decreases as the amount of water 2 in the liquid storage container 1 decreases.

  The liquid level sensor according to the present invention is used in the field of measuring liquid levels of various liquids.

1 liquid storage container (liquid storage body)
2 water (liquid)
3 First liquid storage container 4 First liquid storage container 10 Conduction detection member 11 Conduction wire 12 Bend detection unit (detection unit)
12A Bending detector (detector)
13 Connection detection unit (detection unit)
14 Elongated part 15 Folded part 16 Resin sheet 17 Conductive pattern 18 Detection trunk piece (detection part)
19 Detection piece (detection part)
20 Capacitance detection means

Claims (5)

A conductive detection member that forms a capacitance between the liquid that increases and decreases in the liquid reservoir, and a capacitance detection unit that outputs a detection value according to a change in the capacitance,
The liquid level sensor, wherein the conductive detection member is provided with a plurality of detection units integrally arranged and connected to a capacitance detection unit, and the plurality of detection units are arranged in a height direction. The conductivity detection member includes a conductive wire connected to the capacitance detection means facing the wall of the liquid storage body,
The conductive wire includes a plurality of bend detection units arranged at predetermined intervals in the height direction of the liquid storage body, and a connection detection unit that connects the plurality of bend detection units,
The liquid level sensor according to claim 1, wherein each of the bend detecting units is formed by a conductive wire being substantially coiled and approaching the liquid storage body. The conductivity detection member includes a conductive wire connected to the capacitance detection means facing the wall of the liquid storage body,
The conductive wire includes a plurality of bending detection units arranged at predetermined intervals in the height direction of the liquid storage body, and includes a connection detection unit that connects the plurality of bending detection units,
2. The liquid according to claim 1, wherein each of the bending detecting portions includes an extended portion that extends laterally from an end of the connection detecting portion, and a folded portion that is folded from the end of the extended portion in a substantially bellows shape toward the connection detecting portion. Position sensor. The conductive detection member includes a conductive pattern that is connected to the capacitance detection unit facing the wall of the liquid storage body,
The conductive pattern includes a detection trunk piece that is connected to the capacitance detection means in the height direction of the liquid storage body, and includes a plurality of detection pieces extending laterally from one side of the detection trunk piece, The liquid level sensor according to claim 1, wherein the plurality of detection pieces are arranged at predetermined intervals in a height direction of the liquid storage body. The conductive detection member includes a conductive pattern that is connected to the capacitance detection unit facing the wall of the liquid storage body,
The conductive pattern includes a detection trunk connected to the capacitance detecting means in the height direction of the liquid storage body, and a plurality of detection fragments extending laterally from both sides of the detection trunk. The liquid level sensor according to claim 1, wherein the plurality of detection pieces are arranged at predetermined intervals in a height direction of the liquid storage body.

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