Apparatus and method for measuring or predicting the distribution state of liquid or humidity

Abstract

To provide an apparatus and method for measuring or predicting the distribution of liquid or humidity in an object of arbitrary shape, using a sensor made of a flexible, soft, and non-bulky fiber material that can detect the magnitude of liquid leakage or humidity at three or more multi-level levels. [Solution] A thread-like or fabric-like liquid wetting or humidity sensor made of a fibrous material, capable of detecting the magnitude of liquid wetting or humidity at a multi-level level of three or more values, is placed in two or more areas of an object of arbitrary shape. The distribution state of liquid or humidity in the object is measured or predicted using at least the output value corresponding to the liquid wetting or humidity from each sensor, the change in the output value over time, and the position information of each sensor.

Description

[Technical Field]

[0001] The present invention relates to an apparatus capable of measuring or predicting the distribution state of liquid or humidity, and a method for measuring or predicting liquid leakage or humidity distribution. More specifically, the present invention relates to an apparatus and method in which thread-like or fabric-like liquid wetting or humidity sensors made of fibrous material, capable of detecting the magnitude level of liquid wetting or humidity at a multi-level level of three or more values, are each placed in at least two or more areas of an object of arbitrary shape, and the level of liquid or humidity is measured in real time by each sensor, and based on the obtained level, the liquid or humidity distribution state in the space on the object can be measured or predicted. [Background technology]

[0002] Conventionally, various sensors have been known for detecting the presence or absence of liquids, etc., as follows: The applicant has proposed novel contact sensing members in the following Patent Documents 1 and 2. The contact sensing fiber members disclosed in Patent Documents 1 and 2 can be processed in long lengths, have excellent mass productivity, can be used as warp threads in woven and warp-knitted fabrics, are flexible and have a superior texture, are significantly less expensive than conventional contact sensing fiber members (piezoelectric threads) using piezoelectric materials, and utilize covering technology, a fiber processing technology for which know-how has been established. As a result, processing into fiber members such as woven and knitted fabrics is possible, processing in long lengths is possible, mass productivity is excellent, and a processed yarn with a much better texture can be realized compared to piezoelectric threads.

[0003] Patent documents 1 and 2 disclose a contact sensing fiber member having at least two covering yarns, each consisting of a linear conductor as a core material with insulating fibers wrapped in one direction as a covering material, with two of these covering yarns positioned close to each other. The sensing fiber member detects contact or load of an object by reading the change in resistance between the linear conductors of the two closely positioned covering yarns. Furthermore, since the primary purpose was to detect contact or load, polyester, polylactic acid, and nylon were used as the covering material (sheath yarn), and it was disclosed that moisture could also be detected with these materials. Regarding moisture, only the calculation of △I / I to detect the difference in the presence or absence of moisture (ON / OFF) is described. Patent document 2 states that it is possible to track the drying state after moisture is applied at one location, but the specific method is not disclosed. Optical sensors are disclosed in the following patent documents 3 and 4. Furthermore, various liquid detection sensors, including conductive and capacitive types, are disclosed in the following Patent Documents 5 to 11. Furthermore, Patent Document 12 discloses the arrangement of multiple liquid sensors. However, conventional water and liquid detection sensors, and devices equipped with them, were not capable of measuring or predicting the distribution of fluid leakage, humidity, or dryness in objects of arbitrary shapes, such as diapers, clothing, and bedding like bed sheets, due to human sweating or urinary incontinence, at low cost and in a simple manner. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2022 / 138862 [Patent Document 2] International Publication No. 2023 / 249064 [Patent Document 3] Japanese Patent Publication No. 2022-189365 [Patent Document 4] Japanese Patent Application Laid-Open No. 2023-170176 [Patent Document 5] Japanese Patent Application Laid-Open No. 2003-344334 [Patent Document 6] Japanese Patent Application Laid-Open No. 2003-222602 [Patent Document 7] Japanese Patent Application Laid-Open No. 2016-097227 [Patent Document 8] Japanese Patent Application Laid-Open No. 2007-047153 [Patent Document 9] International Publication No. 2019 / 107165 [Patent Document 10] Japanese Patent Application Laid-Open No. 2022-148437 [Patent Document 11] Japanese Patent Application Laid-Open No. 2021-116601 [Patent Document 12] Japanese Patent Application Laid-Open No. 2018-054021 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] In view of the above-described state of the art, the problems to be solved by the present invention are to be able to detect liquid leakage or humidity levels of three or more values in a multi-value level, and to be composed of a fiber material that is very inexpensive, flexible, has a good texture, and is not bulky, and to provide a device and a method capable of measuring or predicting liquid leakage or humidity distribution states in an object of an arbitrary shape using a long or large-area sensor. [Means for Solving the Problems] <000​​​Moreover, with the above-described configuration, the resulting sensor, despite being very inexpensive, can not only detect the presence or absence of moisture in a binary ON / OFF value, but also the sensor resistance value can change analogously and continuously corresponding to the amount of water present, thereby discovering that the magnitude of the moisture content and the magnitude of humidity can also be detected. Then, by disposing a filamentous or cloth-like liquid wettability or humidity sensor composed of a fiber material, which can detect the level of liquid wettability or humidity in three or more multi-level values, in at least two or more, preferably three or more regions of an object of any shape, respectively, it is considered that the level of liquid leakage or humidity can be measured in real time, and based on the time change characteristics of the obtained level, the liquid leakage or humidity distribution state in the space on the object can be measured or predicted. Therefore, as a result of intensive studies and repeated experiments by the present inventors, it has been newly found that the above problems can be solved by adopting the following configuration, and the present invention has been completed.

[0007] That is, the present invention is as follows. [1] An apparatus in which a filamentous or cloth-like liquid wettability or humidity sensor composed of a fiber material, which can detect the level of liquid wettability or humidity in three or more multi-level values, is disposed in two or more regions of an object of any shape, respectively, and each sensor measures the level of liquid wettability or humidity in real time, and based on the obtained level, the distribution state of liquid or humidity on the object can be measured or predicted. [2] The apparatus according to [1], wherein the filamentous or cloth-like liquid wettability or humidity sensor composed of the fiber material is a multifilament yarn having a core-sheath structure in which an insulating fiber-containing sheath yarn is wound around a conductive core yarn that is a metal fiber or whose surface is covered with a metal, and the sheath yarn is a hydrophilic fiber. [3] The apparatus according to [1] or [2], wherein the outermost surface portion of the conductive core yarn is a non-corrosive metal selected from the group consisting of stainless steel, copper, silver, gold, platinum, gold, and copper tin plating. [4] The apparatus according to [3], wherein the surface of the sheath yarn is a hydrophilic material. [5] The apparatus according to [4], wherein the hydrophilic material is copper ammonium rayon (Bemberg®). [6] The apparatus according to [1] or [2] above, wherein the object of arbitrary shape is a diaper comprising an inner top sheet (nonwoven fabric), an absorbent pad (pad of superabsorbent polymer), an outer film that wraps the absorbent pad on the opposite side of the top sheet, and a gathered portion adjacent to the outer film, and the apparatus detects that the amount of urine absorbed in the diaper is close to saturation by detection by sensors located in the center and its edges of the absorbent pad and near the gathered portion. [7] The following steps: A step of reading the output values ​​of two or more sensors located at different locations using the apparatus described in [1] or [2] above; A step of calculating or measuring the change over time in the output value of each of the two or more sensors; A process of inputting the position information of the two or more sensors and determining the spatial distribution state of liquid leakage or humidity from this position information and the output values ​​of each sensor; A step of calculating a predicted value of the liquid wetting or humidity state after a predetermined period of time at the time of sensor output, based on the output value of each sensor, the change in output over time, and the position information of each sensor; and A method for measuring or predicting the distribution state of liquid wetting or humidity in a space of an object of arbitrary shape, comprising the step of presenting at least one of the obtained distribution state or predicted value. [Effects of the Invention]

[0008] The sensor used in the apparatus according to the present invention, which can measure or predict the distribution state of liquid or humidity in an object, is flexible, has a good texture, can be processed into long lengths, can be used as warp threads in woven or warp-knitted fabrics, and is easy to fix to nonwoven or woven fabrics. Therefore, it can measure the state of liquid wetting or humidity in a space of an object of any shape, not at a single point, but in a linear or planar area. Furthermore, it is highly mass-producible, resulting in significantly lower costs, and the apparatus using it is also low-cost. In this way, measurement of the positional distribution of liquid wetting, humidity, or dryness over a large area becomes possible using a low-cost fiber material with a very good texture, and the positional distribution of liquid and the time-dependent changes in wetting spread can be measured in real time, making it possible to predict before areas that should not be wet (or dried) become wet (or dry). As a result, it becomes possible to automatically grasp the distribution state of liquid leakage and humidity, and predict and forecast the occurrence of abnormalities, in real time, without the need for people to directly measure around. Furthermore, by using machine learning to analyze the vast amount of data on the trends of these values, it becomes possible to analyze anomaly occurrences and understand patterns, enabling more accurate predictions and forecasts. Therefore, using this sensor, it is possible to realize a device or method for measuring or predicting the presence or absence of liquid and the humidity distribution in objects of arbitrary shape, such as curtains, bed sheets, diapers, clothing, sheets and mats, noren curtains, sunshades, etc., at low cost and in a simple manner. For example, it becomes possible to measure or predict the distribution of human sweating and dampness in bedding such as bed sheets and comforters for the prevention of pressure ulcers, as well as to detect the urine absorption state in diapers and predict the occurrence of leakage. Alternatively, it can be used to measure and predict the occurrence of wetting during cargo transport in logistics centers, and to prevent water damage; measure and predict indoor humidity distribution using curtains or noren; measure humidity distribution and predict humidity changes in transport rooms for freezing and refrigeration; measure or predict soil moisture and fertilizer conditions linearly or in a planar manner rather than at specific points in agriculture and horticulture; measure and predict humidity distribution in greenhouses, enabling the prediction and prevention of disease outbreaks caused by prolonged exposure to high humidity; predict fluctuations in liquid level in chemical tanks in chemical plants in multiple stages; detect leaks at multiple points in piping; and predict overflow in revetments in civil engineering. Furthermore, the apparatus and methods according to the present invention are not limited to these applications but can be widely used for various other purposes. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of an example of the structure of a thread-like or fabric-like liquid wetting or humidity sensor made of fibrous material, capable of detecting the magnitude of liquid wetting or humidity at three or more levels. [Figure 2] The diagram (or photograph) illustrates an object of arbitrary shape consisting of a diaper comprising an inner top sheet (nonwoven fabric), an absorbent pad (absorbent polymer pad), an outer film that wraps the absorbent pad on the opposite side of the top sheet, and a gathered section adjacent to the outer film, as well as the locations where sensors are installed (circle 1, circle 2, circle 2', circle 3). [Figure 3] This graph shows the detection results from each sensor placed in the central part of the absorbent pad (circle 1), both ends of the absorbent pad (circles 2 and 2'), and between the absorbent pad and the outer film (inside the gathered portion) (circle 3) in Example 1. [Figure 4] This is a schematic diagram of a cloth with four sensors mounted on it, as used in Example 2. [Figure 5] This is an explanatory diagram of the wetting level in Example 2. [Figure 6] This is an explanatory diagram showing the relationship between the wet level value and the prediction index in Example 2. [Figure 7] This is a photograph showing the state of spraying water onto Ch.1, Ch.2, Ch.3, and Ch.4 in Example 2. [Figure 8] This graph shows the time variation of the resistance values ​​of each sensor in Example 2. [Figure 9] The wetting levels of each sensor at each time point t1 to t8 in Example 2, and the values ​​of the predictive index P calculated from these values ​​are shown. [Figure 10] Figure 9 shows an example of a monitor screen displaying the wet state immediately before t8. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below. One embodiment of the present invention is a device in which thread-like or fabric-like liquid wetting or humidity sensors made of a fibrous material, capable of detecting the magnitude of liquid wetting or humidity at a multi-level level of three or more values, are placed in two or more areas of an object of arbitrary shape, and each sensor measures the level of liquid or humidity in real time, and based on the obtained levels, the distribution state of liquid or humidity in the object can be measured or predicted. Preferably, the yarn-like or fabric-like liquid wetting or humidity sensor made from the fibrous material is a multi-twisted yarn having a core-sheath structure in which a sheath yarn containing insulating fibers is wrapped around a conductive core yarn which is a metal fiber or whose surface is covered with metal, and the sheath yarn is a hydrophilic fiber. Hereinafter, the multi-twisted yarn may be referred to as a sensing fiber member.

[0011] The linear conductor (core thread) used as the core material is not particularly limited as long as it is conductive, but it may be a linear conductor whose material itself is conductive, such as a conductive fiber, or a linear conductor in which conductivity has been imparted to a non-conductive fiber. The former is preferable if it is a metal fiber made from stainless steel, as it ensures corrosion resistance and simplifies termination processing for connection to circuits, etc. The latter is preferable from the viewpoint of improving texture and flexibility, such as using a material in which metal plating such as silver or copper is applied around a nylon fiber, or a material in which metal foil is processed into a tape shape and wound around a fiber, or a material in which an aerosol-like conductor is applied to the surface of a fiber by spraying it. In this case, it is preferable that the conductive fiber is made of multifilaments, as this provides good conductivity and increases strength. Furthermore, from the viewpoint of detecting sweat and urine, it is preferable that the outermost surface of the conductive core thread be a non-corrosive metal selected from the group consisting of stainless steel, copper, silver, gold, platinum, and copper-tin plating. Furthermore, the linear conductor may consist of one or more metal wires, although this may worsen the texture, from the standpoint of cost reduction. For example, using metal wires with a diameter of approximately 30 μm to 1 mm can significantly increase the strength.

[0012] The fineness of the linear conductor, for example, conductive fiber, is preferably 10 dtex to 15,000 dtex, and more preferably 20 dtex to 5,000 dtex, from the viewpoint of easily obtaining a good texture. In the case of a multifilament, the fineness of the single filament is preferably 1 dtex to 30 dtex, and more preferably 2 dtex to 10 dtex, from the viewpoint of easily obtaining a good texture and easily obtaining high conductivity. The number of filaments is more preferably 10 to 200. Having 10 or more filaments is preferable because it is easier to obtain a good texture and ensure good conductivity. However, if the number of filaments is too high, the cost will increase and the rigidity will also increase, which may conversely reduce the texture. Considering all of these factors, it is preferable to keep the number of filaments within the above range.

[0013] The conductive material forming the linear conductor may be the same material between the two covering yarns in a pair, or different materials may be used; any combination of materials can be used. For contact, load, and tension sensing applications, using the same conductive material is preferable because it allows for efficient production. When sensing liquids such as water, if different materials are used as the linear conductors of the two covering yarns in a pair, a voltage or current is generated by an electrochemical action called galvanic action when the liquid adheres to these different materials, enabling liquid sensing without a power source. Examples of combinations of different materials include iron and copper, iron and silver, aluminum and copper, silver and copper, and any other combination can be used.

[0014] In this specification, the term "insulating fiber" as a covering material (also called sheath thread or cover thread) is not particularly limited as long as it can electrically insulate two pairs of linear conductors that serve as the core material as described above. However, it is preferable that the fiber is hydrophilic and sensitive to changes in humidity and dryness over time in order to detect wetting and humidity. It is preferable that the surface of the sheath thread is made of a hydrophilic material. The resistance between linear conductors of covering yarns placed in close proximity to each other (sensor resistance) is within the range of 0.5kΩ to 5GΩ, and the sensor resistance is 20 times to 1 × 10⁻¹⁶ times the resistance of the linear conductors alone (wiring resistance). 9 It is preferable that it is twice as much. This prevents electrical short circuits when a voltage is applied between two linear conductors constituting two adjacent covering yarns, and because the sensor resistance is sufficiently large compared to the wiring resistance, detection can be performed correctly without being affected by the wiring resistance. It is even preferable that the sensor resistance is in the range of 1kΩ to 1GΩ, as this simplifies the readout circuit. The range of electrical resistivity of the sheath yarn material is 10 4 Ω·m~5×10 9 A resistance of Ω·m is preferable because it easily satisfies the above-mentioned range of sensor resistance values. Furthermore, a higher sensor resistance value is practically preferable from an energy-saving standpoint because it can reduce the standby current during measurement.

[0015] In this embodiment, the multi-twisted yarn (sensing fiber member) preferably uses a combination of fibers that dry more quickly as the material of the covering material (sheath yarn, cover yarn). In particular when sensing moisture, using quick-drying fibers for the cover yarn allows it to dry quickly after coming into contact with moisture, thus returning to its original state more quickly. Cellulose fibers are particularly preferred as quick-drying fibers. Suitable cellulose fibers include natural cellulose fibers such as cotton and linen, regenerated cellulose fibers such as rayon, polynosic, lyocell, cupro (copper ammonium rayon, Bemberg®), and modal, and semi-synthetic fibers such as acetate, with cupro being the most preferred. Multifilament long fibers are particularly preferred.

[0016] The fineness of the insulating fiber is preferably 15 dtex to 25,000 dtex, and more preferably 30 dtex to 8,000 dtex, from the viewpoint of easily ensuring insulating properties. Furthermore, in the case of multifilament, the fineness of the single filament is preferably 1 dtex to 10 dtex, and more preferably 2 dtex to 8 dtex, from the viewpoint of more easily obtaining a good texture. Also,

[0017] There are no particular limitations on the apparatus for measuring the resistance change between two covering yarns, each consisting of a linear conductor as a core material and covered with multifilament insulating fibers wound in one direction as a covering material. The conductive fibers are opened at the ends of the two covering yarns, and a source meter (SMU, source measure unit) capable of supplying voltage and current while simultaneously measuring voltage, current, and resistance is connected to measure the resistance between the pair of covering yarns. Alternatively, without using such measuring equipment, a readout circuit consisting of an analog / digital conversion circuit, a current-voltage conversion circuit, an amplification circuit, etc., can be fabricated and used to measure the resistance.

[0018] The sensing fiber member of this embodiment can detect external forces by changing the impedance between two linear conductors in response to external forces. If a substance that can cause this impedance change is included between the two linear conductors, the presence or absence of this substance can be detected. For example, if water other than ultrapure water such as tap water, saline solution, an ion drink, or a mixture of water and ethanol is dropped between two linear conductors, the resistance between the linear conductors decreases significantly and the current between them increases, allowing the presence or absence of these liquids to be detected. Similarly, since an impedance change occurs when humidity changes, it can also be used as a humidity sensor. The yarn-like or fabric-like liquid wetting or humidity sensors made of fibrous material according to this embodiment can be placed in two or more areas on an object of arbitrary shape, and can detect linear, planar, or three-dimensional spatial ranges. For example, a bed sheet (approximately 0.5-2m wide and 1-2.5m long) can be divided into multiple sections (3-20 sections), and sensors can be placed in each section to measure moisture or humidity. Furthermore, moisture at a specific location can be predicted from its position, displacement, and change. For instance, when performing sensing at 20 locations, divided into 4 sections in the width direction and 5 sections in the length direction, conventionally it was necessary to place an individual sensor in every section. However, in this embodiment, by placing sensors of roughly the same length as the sheet so as to span the sections in both the length and width directions, measurement and prediction for all 20 sections can be performed with just 9 sensors, thus reducing the number of sensors required. Furthermore, by strategically placing the absorbent material of a diaper (approximately 10-20 cm wide and 20-50 cm long) in adjacent areas (near the gathers, where urine leakage should not occur), it becomes possible to predict urine leakage.

[0019] Other embodiments of the present invention include at least the following steps: A process of reading the output values ​​of two or more sensors located at different locations using the aforementioned device; A step of calculating or measuring the change over time in the output value of each of the two or more sensors; A process of inputting the position information of the two or more sensors and determining the spatial distribution state of liquid leakage or humidity from this position information and the output values ​​of each sensor; A step of calculating a predicted value of the liquid wetting or humidity state after a predetermined period of time at the time of sensor output, based on the output value of each sensor, the change in output over time, and the position information of each sensor; and A step of presenting at least one of the obtained distribution state or predicted value; This method involves measuring or predicting the distribution of liquid wetting or humidity in a space within an object of arbitrary shape. An example of an embodiment is described below.

[0020] As a predictive system for preventing liquid wetting, a sheet is prepared by arranging n sensors (where n is an integer of 3 or more) according to the present invention within a cloth, and as shown in Figure 4, the sensors are defined as the i-th sensor (where i is a natural number from 1 to n) in the order of their position coordinates. As shown in Figure 6, the output value of each sensor is read at a certain time t, and the level of liquid wetting in the area of ​​the obtained i-th sensor is expressed as a function of time t, W i Let (t) be used here for explanatory purposes. i Let (t) ≥ 0, and assume that a larger value of W indicates a greater degree of wetting. Also, let k be an integer outside the range of 1 to n (k < 1 or k > n), and W k Let (t) = 0. Furthermore, the sensor output values ​​may be read by directly reading the resistance value of each sensor with a resistance meter, or by using a circuit in which a known electrical resistance and each sensor are connected in series, and a circuit is used to read the voltage value at a fixed point on the circuit. Alternatively, a Wheatstone bridge or a multi-stage comparator circuit may be used, and the method of reading the output values ​​according to the liquid wetting and humidity of each sensor is not limited to this invention. Also, W represents the liquid wetting level. i (t) may be the value obtained by directly converting the analog output of the sensor to digital, or, as shown in Figure 5, the liquid wetting level value may be defined according to the sensor output value based on a pre-set multi-stage threshold, and should be determined appropriately depending on the application. Next, at time t + Δt, which is Δt after time t, an index P indicating the possibility of liquid wetting in the i-th sensor area is defined as follows. i (t + Δt) is defined as follows. P i (t + Δt) = A1 * (W i+1 (t) + W i-1 (t)) + A2 * (W i+2 (t) + W i-2 (t)) + … + A n-1 * (W i+(n-1) (t) + W i-(n-1) (t)) Here, A1, A2 ··· A n-1 are constants determined according to the purpose of use, and A1 > A2 > ··· > A n-1 > 0. That is, as a prediction index of wetting occurrence, it is an index that weights the wetting level values of sensors adjacent to the target sensor more heavily and reduces the degree of reflection from the output values of sensors at distant positions. As an example, the measurement or prediction method when there are four areas where sensors are arranged will be described below using the block diagram shown in FIG. 6. Using the above definition, for example, the index P2(t + Δt) indicating the possibility of liquid wetting in the area of the second sensor is P2(t + Δt) = A1 * W1(t) + A1 * W3(t) + A2 * W4(t) , Here, A1 > A2 > 0 is set. Thus, an index can be calculated that weights the current wetting level values of the first and third sensors adjacent to the second sensor more heavily and reduces the influence of the wetting level of the fourth sensor at a more distant position. By calculating this P2(t) value each time the sensor output value is captured, the risk of wetting occurrence in the area of the second sensor can be predicted. The same operation is performed for the other first, third, and fourth sensors. Furthermore, for the liquid wetting level W i (t), the change ΔW i(t) is determined by measurement or calculation. This can be done by storing the time change of the sensor output value in memory and calculating the difference between the output value from a certain time period ago and the current output value in real time, or by directly measuring the relationship between past values ​​and current values ​​using a multi-stage comparator or similar circuit. ΔW i If (t) is a positive value, it indicates that the degree of wetting is increasing, and conversely, if it is a negative value, it indicates that drying is progressing. Furthermore, the magnitude of this value can be used to determine the degree of wetting or drying. ΔW i For (t), similar to the method described above, an index P' is used, which heavily weights the influence of adjacent sensors and lessens the influence of distant sensors, based on the positional information of each sensor. i By appropriately defining (t), it is possible to predict the future wetting state of the sensor of interest.

[0021] The liquid wetting level W obtained at each sensor as described above. i (t), prediction index P i (t), ΔW i Another predictive index P' based on (t) i (t) At least one of the indicators shall be presented. The method of presentation may include displaying it on a screen or a remote computer, vibrating, sounding a warning, or illuminating a warning light, etc., to inform users and related parties, or it may be a method of sending predetermined commands or data to another device without human intervention. Furthermore, to obtain a predicted wetness value, the results of comparing the magnitudes of each sensor output value or the difference between each sensor output value can be calculated and used for prediction. Setting more indicators for analysis may enable more accurate prediction and measurement, but these can also be omitted as appropriate to reduce the time required for calculation. The indicators used for prediction should be determined according to the application of measurement and prediction of the object, such as whether it is necessary to detect the constantly changing situation without fail, or whether intermittent recording once every few minutes or hours is sufficient, whether the circuit used for analysis can be made somewhat large, or whether it is necessary to read the data using a power-saving circuit in a space-saving manner of a few centimeters or less.

[0022] In the above embodiments, the device was used as a measuring or predicting device to prevent liquid wetting. However, in another example, it can also be used when it is desired to maintain humidity within a certain high range. In this case as well, the sensor output value corresponding to the humidity is measured, its fluctuation over time is measured, a future predicted value is defined based on the positional information of the sensors, and this is calculated from the measured values ​​of each sensor. For example, in the transportation and storage of fresh food products, maintaining freshness requires that the humidity throughout the storage area, such as transport containers and refrigerated spaces, be kept within a certain range. By installing sensors near entrances and doors where humidity fluctuations are most likely to occur, as well as on the ceiling, central walls, and bottom of the storage area, it is possible to understand the humidity distribution inside the box at low cost, predict humidity fluctuations in the storage area, and issue alerts as needed. Alternatively, when applied to greenhouse cultivation, conventional methods only allowed for point-level humidity measurement, requiring numerous expensive sensors for multi-point humidity measurement. However, using the embodiment of this invention, long-length sensors can be embedded in the soil to detect soil dryness and wetness over a wide area, and to measure and / or predict the distribution of moisture levels at each sensor location. Furthermore, by placing sensors at multiple locations on the greenhouse wall, the humidity distribution within the greenhouse can be understood and its condition predicted. This enables prediction of disease outbreaks caused by prolonged exposure to high humidity environments, and allows for optimal humidity and air conditioning management by linking the predicted data with the greenhouse's air conditioning control mechanism. [Examples]

[0023] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The measurement methods for each characteristic value used in the following examples were as follows.

[0024] (1) Measurement of resistance (current) The resistance between two linear conductors in two adjacent covering yarns was measured by electrically disconnecting the two linear conductors at one end of the covering yarn and simultaneously supplying voltage and current between the two linear conductors at the other end, while connecting a source meter (SMU: Source Measure Unit, Keithley 2614B) capable of measuring voltage, current, and resistance. 100mV was applied between the two linear conductors, and the change in current (or resistance) during moisture dripping and drying was monitored. The measurement environment was 25°C and 34%RH.

[0025] [Example 1] As a yarn-like or fabric-like liquid wetting or humidity sensor (sensing yarn) made from a fibrous material that can detect the magnitude of liquid wetting or humidity at three or more levels, a double covering yarn was prepared using metal fiber (Naslon) (registered trademark) (manufactured by Nippon Seisen Co., Ltd., product no. 12-100, steel type SUS304, fiber diameter 12 μm, basis weight 0.11 g / m, thickness 0.11 mm) as the core yarn and Bemberg (registered trademark) (manufactured by Asahi Kasei Corporation, cupro regenerated cellulose fiber, product no. SNP, fineness 110 dtex, filament count 60) as the sheath yarn, and two of these were bundled together and further twisted into a multi-twisted yarn. Using two bobbins of the above-mentioned sheath yarn, each was twisted in a Z-shape, and the core yarn was covered with it so that the twist count was Z900T / m. The two resulting double-covered yarns were then combined and twisted in an S-shape to produce a multi-twisted yarn with a twist count of S320T / m. The fineness of this insulating fiber was 4178 dtex. The twist coefficient of this multi-twisted yarn is K=(SS+SC). 1 / 2 The twist coefficient K, expressed as ×R{wherein SS is the fineness (dtex) of the linear conductor as the core material, SC is the total fineness (dtex) of the covering material, and R is the number of turns (twists) (turns / m) of the covering material}, was 38814. Figure 1 is a schematic diagram of the structure of the obtained twisted yarns.

[0026] As a diaper, I obtained Lifree Secure-Fit Paper Pants Pad (16cm wide x 45.5cm long) manufactured by Unicharm Corporation. As shown in Figure 2, the above diaper consists of the following main components: an inner top sheet (nonwoven fabric), an absorbent pad (a pad made of superabsorbent polymer), an outer film that wraps the absorbent pad on the opposite side of the top sheet, and a gathered section adjacent to the outer film. As shown in Figure 2, each sensing thread, 20 cm in length, was positioned to pass through the entire length of the diaper, in the center of the absorbent pad (circle 1), both ends (circles 2 and 2'), and just inside the gathered section on the top sheet (circle 3). A source meter was connected to one end of each sensing thread, and 100 mL of water was poured into the center of the absorbent pad in two separate pours. The resistance value of each sensing thread was then measured.

[0027] The results are shown in Figure 3. In the central part of the absorbent pad (circle 1), and at both ends (circles 2 and 2'), the resistance changed (decreased) from approximately 1 GΩ to 100 KΩ from the time of the first 100 mL of water injection. This change indicated a significant increase in moisture (wetting), and the resistance remained at approximately 1 MΩ for about 60 minutes thereafter. On the other hand, in the space between the absorbent pad and the outer film (inside the gathered section) (circle 3), the change during the first injection of 100 mL of water was small, and thereafter remained at approximately 100 MΩ for about 60 seconds. Subsequently, a second injection of 100 mL of water was performed. In circles 1, 2, and 2', a small change in resistance level was detected, decreasing from approximately 1 MΩ to 100 KΩ. However, after about 10 seconds, it returned to approximately 100 MΩ and remained at that level. In contrast, in test 3, the second addition of 100 mL of water caused the resistance to change (decrease) from approximately 100 MΩ to approximately 100 KΩ. This change indicated a significant increase in moisture (wetting), after which the resistance remained at approximately 1 MΩ. By measuring how much water the absorbent material can hold, it becomes possible to make future predictions. (In this example, it is possible to predict that urine leakage will occur a certain time after the first water application (depending on the frequency of urination).) From these results, it can be seen that applying the present invention to diapers makes it possible to predict urine leakage.

[0028] [Example 2] To simulate water damage detection and prediction during cargo transport at a logistics center, a cloth was prepared with four sensors mounted on it, similar to those in Example 1 except for its length of 30 cm, as shown in Figure 4. The sensors were numbered Ch.1, Ch.2, Ch.3, and Ch.4 from left to right. Here, as shown in Figure 7, a cardboard box was placed on Ch.1, and the area where this sensor is located was designated as a region where wetting should not occur. In this system, approximately 10 mL of tap water was sprayed onto the sensor area of ​​Ch.4, and 30 seconds later, approximately 10 mL of tap water was similarly sprayed onto the sensor area of ​​Ch.3. Figure 8 shows the time change in the resistance value of each sensor at this time. Here, as shown in Figures 5 and 6, the wetting level is denoted as W, and W=0 when the sensor resistance value is 1 GΩ or more, W=1 when it is 20 MΩ or more but less than 1 GΩ, W=2 when it is 3 MΩ or more but less than 20 MΩ, W=3 when it is 1 MΩ or more but less than 3 MΩ, and W=4 when it is less than 1 MΩ. Furthermore, let P be the index for wetness prediction at each time and each sensor. P = (sum of wet levels of adjacent sensors) × 5 + (wet level of the remaining sensor) × 1 Figure 9 shows the wetting levels of each sensor at each time point t1 to t8 in Figure 8, and the values ​​of the prediction index P calculated from these values. Furthermore, the displayed content was changed according to these prediction index values ​​and wetting levels. That is, When the wetness level is 1 or higher, the displayed message is "Wetness occurred." In all other cases, when the predictive index P is 0, the displayed content is "normal". When the predictive index P is between 1 and 5, the message displayed is "Caution advised." When the predictive index P is between 6 and 10, the message is "dangerous". When the predictive index P is greater than 10, the message is "particularly dangerous". That's what I decided. The two rightmost columns of Figure 9 show the information presented based on the prediction index P in Ch.1 and Ch.2. According to this, using this prediction index, it was possible to predict the occurrence of wetting in Area 1 from time t2, which is considerably earlier than the actual wetting time t8, and to generate an alert corresponding to this prediction index. For example, Figure 10 is an example of a monitor screen showing the wet state just before t8 in Figure 9, and it is possible to monitor the wetting level and the prediction index P using such a monitor screen. [Industrial applicability]

[0029] The present invention provides a device capable of measuring or predicting the liquid wetting or humidity distribution state in a space on an object of arbitrary shape, and the yarn-like or fabric-like liquid wetting or humidity sensor (sensing yarn) made of a fibrous material, which can detect the magnitude level of liquid wetting or humidity at three or more multi-level levels, is preferably a multi-twisted yarn having a core-sheath structure in which a sheath yarn containing insulating fibers is wrapped around and covered with a conductive core yarn which is a metal fiber or whose surface is covered with metal, and the yarn is multi-twisted. Therefore, the sensor can be processed in long lengths, is highly productive for mass production, can be used as warp thread in woven or warp-knitted fabrics, is easy to fix to nonwoven fabrics, is flexible and has a superior texture, is significantly low-cost, and the equipment using it is also low-cost. Therefore, using this sensor, it is possible to realize a device or method that can easily and inexpensively measure or predict the distribution of moisture, humidity, or dryness in objects of any shape, such as diapers, clothing, or bedding such as bed sheets in cases of pressure ulcers, due to human sweating, urinary incontinence, etc. Specifically, it becomes possible to measure the location distribution of liquid wetting, humidity, or dryness over a large area using low-cost textile materials with a very pleasant texture. Furthermore, since the location distribution of liquid and the temporal changes in wetting can be measured in real time, it becomes possible to predict when areas that need to be prevented from getting wet (or drying) will get wet (or dry). Furthermore, the apparatus and method according to the present invention are not limited to diapers, clothing, and bedding such as bed sheets, but can be widely used for various other applications.

Claims

1. A device comprising thread-like or fabric-like liquid wetting or humidity sensors made of fibrous material, capable of detecting the magnitude of liquid wetting or humidity levels at three or more multi-level levels, each sensor placed in two or more areas of an object of arbitrary shape, which measures the level of liquid wetting or humidity in real time, and which can measure or predict the distribution state of liquid or humidity in the object based on the obtained levels.

2. The apparatus according to claim 1, wherein the thread-like or fabric-like liquid wetting or humidity sensor made of the aforementioned fibrous material is a multi-twisted yarn having a core-sheath structure in which a sheath yarn containing an insulating fiber is wrapped around a conductive core yarn which is a metal fiber or whose surface is covered with metal, and the sheath yarn is a hydrophilic fiber.

3. The apparatus according to claim 1 or 2, wherein the outermost surface of the conductive core thread is a non-corrosive metal selected from the group consisting of stainless steel, copper, silver, gold, platinum, gold, and copper-tin plating.

4. The apparatus according to claim 3, wherein the surface of the sheath thread is made of a hydrophilic material.

5. The apparatus according to claim 4, wherein the hydrophilic material is copper ammonium rayon (Cupro, Bemberg®).

6. The apparatus according to claim 1 or 2, wherein the object of arbitrary shape is a diaper composed of an inner top sheet (nonwoven fabric), an absorbent pad (a pad of superabsorbent polymer), an outer film that wraps the absorbent pad on the opposite side of the top sheet, and a gathered portion adjacent to the outer film, and the apparatus detects that the amount of urine absorbed in the diaper is close to saturation by detection by sensors positioned in the central part and its edges of the absorbent pad, and near the gathered portion.

7. The following steps: A step of reading the output values ​​of two or more sensors located at different locations using the apparatus described in claim 1 or 2; A step of calculating or measuring the change over time in the output value of each of the two or more sensors; A step of inputting the position information of the two or more sensors and determining the spatial distribution state of liquid leakage or humidity from this position information and the output values ​​of each sensor; A step of calculating a predicted value of the liquid wetting or humidity state after a predetermined period of time at the time of sensor output, based on the output value of each sensor, the change in output over time, and the position information of each sensor; and A step of presenting at least one of the obtained distribution state or predicted value; A method for measuring or predicting the distribution of liquid wetting or humidity in a space within an object of arbitrary shape, including [a specific example].

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