SENSOR DEVICE

Description

[0001] The invention relates to a sensor device for determining moisture using an electrical conductivity measurement, wherein a non-conductive carrier has individual electrical conductors, wherein the respective electrical conductor (38) is an integral part of an adhesive closure part (8) and wherein the electrical resistance between the electrical conductors depends on the amount of moisture on the carrier and the electrical conductors.

[0002] EP 0 403 994 B1 discloses a capacitive humidity sensor consisting of a capacitor with at least two metallic layers forming the electrodes, at least one of which is permeable to water vapor, wherein a moisture-sensitive polymer film is provided as a dielectric between the electrodes.

[0003] The change in the capacitance of the humidity sensor known in this way in the presence of air with different moisture content is due to the fact that the water molecules in the air diffuse into the polymer film forming the dielectric and thus measurably change the dielectric constant and consequently the capacitance value of the capacitor formed in this way.

[0004] DE 195 19 099 Cl discloses another humidity sensor, wherein electrodes are applied to a non-conductive substrate, preferably the windshield of a motor vehicle, and wherein the resistance between the electrodes depends on the amount of moisture present on the substrate and the electrodes, which consist of conductive tracks of high electrical conductivity covered by a resistive layer of low electrical conductivity. With the known humidity sensor, in particular those amounts of moisture relevant for controlling windshield wipers can be reliably determined.

[0005] EP 3 192 482 A1 relates to a moisture detection device for a device used to monitor access to a patient. A section of the device is deformable into a cuff which can be repositioned around the circumference of a hose, the device having fastening means for this purpose. In one embodiment, the fastening means each have a strip provided with an adhesive or bonding layer. The device preferably further comprises an electrically conductive structure integrated into a textile fabric, which is used for moisture detection. The electrically conductive structure can be formed by conductive warp and weft threads of the fabric.

[0006] Based on this prior art, the invention aims to create a sensor device for determining humidity that is more versatile than known solutions. A sensor device with the features of claim 1 in its entirety achieves this objective.

[0007] Because the electrical conductor is an integral part of the adhesive fastener, a sensor device is created that can be used in a wide variety of ways, as it can be attached almost anywhere on-site in a reversible manner due to the fastener's adhesive nature. Such an adhesive fastener, without the electrical conductor, is typically part of a fastener that can be opened and closed almost any number of times, for which the patent holder has become highly well-known both in the professional community and among consumers under the trademark Kletten®.

[0008] The adhesive-backed component with the electrical conductors, preferably equipped with barbs, can be hooked onto itself, thus enabling it to be attached as a standalone solution wherever moisture measurement is required. Even in hard-to-reach places, the sensor device with its flexible adhesive-backed component can be easily and repositionably attached for moisture detection. This repositionable adhesive-backed component can also be manufactured as an extra-thin micro-extruded film with a three-dimensional structure, achieving a high degree of flexibility. Furthermore, such an adhesive-backed component with its elastic conductor is flexible and resistant to both temperature and washing. Depending on the plastic material used for the non-conductive carrier, the adhesive-backed component and its electrical conductor are also resistant to chemicals.

[0009] In the sensor device according to the invention, the adhesive closure element consists of a base fabric made of warp and weft threads, which is at least partially penetrated by at least one functional thread. This functional thread partially protrudes beyond the base fabric to form the individual closure elements, and the electrical conductor is woven into the base fabric as a further functional thread. Besides such a woven structure for the adhesive closure element, it can also be produced in a knitted version or, in an alternative embodiment, as a cast microreplication product, in which case the electrical conductors are embedded at least partially exposed in the cast, non-conductive base material. In any case, a planar, and in particular band-shaped, adhesive closure element can be realized cost-effectively as a woven closure component, with the electrical conductor being partially exposed and woven into the base fabric.In this way, large quantities of sensor devices can be continuously obtained and cut to length by separating them from the belt.

[0010] In a particularly preferred embodiment of the sensor device according to the invention, one functional thread forms individual loops which are cut open to form hook elements and preferably subjected to heat treatment at the ends thus obtained, forming thickenings at the head. These thickenings at the head regularly form mushroom-shaped closure heads for the adhesive closure part, which can interlock particularly well with a suitable nonwoven or loop material of another or the same adhesive closure part. Thus, the adhesive closure part with the electrical conductors can have the hook elements on one side and a loop or loop material on the opposite side with which the hook elements can interlock accordingly.It is also possible to create both hooks and loop or hook elements on the same side in order to form a permanently resealable closure mechanism.

[0011] It is particularly preferred that each additional functional thread is woven into the base fabric as a linear electrical conductor in the form of a warp thread.

[0012] Particularly good results can be achieved if the subsequent functional thread of the sensor device consists of a stainless multifilament stainless steel yarn, while the non-conductive carrier or base fabric of the adhesive fastener is made of a plastic material such as polyamide or polyester. The non-conductive yarns of the adhesive fastener are preferably made of hydrophobic materials such as polypropylene and / or polyester, and such hydrophobic materials dry faster, so that the sensor is available again for moisture detection relatively quickly.

[0013] In a further preferred embodiment of the sensor device according to the invention, the additional functional threads are arranged in pairs and run parallel to each other at a predefinable distance from one another within the adhesive closure part. Preferably, the adhesive closure part is designed as a planar, flexible band, along whose two longitudinal edges the additional functional thread runs in the form of an electrical conductor over the entire length of the band. In this way, a defined measurement situation is created, which facilitates obtaining reproducible measurement results with the sensor device according to the invention for a wide variety of measurement applications.

[0014] The electrically conductive functional threads are preferably bonded firmly to a non-conductive polyurethane layer on the reverse side. A surface-mounted adhesive fastener is preferably attached to this layer, forming a releasable hook-and-loop fastener with the fastener elements of the adhesive fastener itself. This surface-mounted adhesive fastener can be a velour material, which, when necessary, can be brought into engagement with the mushroom-shaped fastener elements of the base fabric to form the hook-and-loop closure. The non-conductive layers are important because they ensure that no short circuit occurs when the adhesive fastener, with its integrally integrated conductors, comes into contact with metallic components such as a metal pipe. This is regularly the case when the moisture detection sensor is attached to such metallic components.

[0015] For reading the sensor values, it is preferably provided that electrical contact points are embedded or applied to the strip-shaped adhesive closure part, into which the respective functional thread in the form of the electrical conductor terminates. This achieves a particularly space-saving measurement point on the adhesive closure part. The contact points can be solder joints or, preferably, consist of plug-and-socket solutions.

[0016] In a further particularly preferred embodiment of the sensor device according to the invention, an evaluation unit for the measurement data is connected to each of the other functional filaments, i.e., the electrical conductors. In addition to capacitive measurement data evaluation, as described in the prior art, it is also possible to send an electric current through an electrical conductor of the sensor device using a voltage source. A display unit connected to both electrical conductors determines the magnitude of the electric current flowing, which then serves as a measure of the respective humidity present on the otherwise non-conductive substrate due to the humidity of the surrounding atmosphere. In this respect, an electrical resistance measurement is implemented, and the higher the humidity, the lower the electrical resistance and the higher the measured value displayed on the display unit.

[0017] The invention also relates to an adhesive closure element as part of a sensor device as described above, comprising non-conductive functional threads that form individual closure elements protruding from a non-conductive base fabric, and electrically conductive functional threads as an integral component of the base fabric. In this way, an adhesive closure element as a basic component can subsequently be coupled on-site with a variety of different sensor evaluation devices. This has no equivalent in the prior art.

[0018] The sensor device according to the invention will now be explained in more detail with reference to an exemplary embodiment as shown in the drawing. The drawing shows, in a general and not to scale, the following: Figure 1 shows the tissue image of the sensor device with integrated electrical conductors; Figure 2 shows a side view of the flat adhesive closure part after the Figure 1; and Figure 3, in a highly simplified manner, shows a top view of sections of a ribbon-shaped sensor device with an attached evaluation unit.

[0019] The Figure 1 shows a partial top view of a flat adhesive fastener component, as used in the Figure 3 The component designated 8 serves as the basic component for the sensor device according to the invention. The adhesive closure element 8 can be extended arbitrarily within the image plane in both the one and the other image direction, and the geometric dimensions of the surface structure depend on the specifications of the weaving device on which the adhesive closure element is manufactured.

[0020] The adhesive fastener part 8 consists of warp threads 10 and weft threads 12, which are interwoven in a transverse arrangement to form the base fabric 14 for the adhesive fastener part 8. Furthermore, the base fabric 14 is designed with functional threads 16 in the manner of pile threads, and the respective functional thread 16 forms the individual fastening elements 18 for the planar adhesive fastener part. Furthermore, looking towards the Figure 1 seen on its upper side with an arrow 20 indicating the production direction for the adhesive fastener part 8 in the context of weaving production.

[0021] In the arrangement shown, according to the Figure 1The respective weft threads 12 are formed in an arc shape resembling a sine or cosine wave, and at the intersections between warp threads 10 and weft threads 12, the warp threads 10 run parallel to the production direction 20 and parallel to each other in a straight line. The wave- or arc-shaped design of the weft threads 12 creates a defined mechanical resistance that counteracts any potential out-of-engagement movement of the corresponding fastening elements. However, it is understood that the aforementioned weft threads 12 can also run in a straight line parallel to each other, and this configuration forms the basis for the band-shaped sensor device according to the Figure 3 The respective functional thread 16 runs at least partially between two adjacent warp threads 10 in the base fabric 14, whereby in the Figure 1In the arrangement shown, every fourth weft thread 12 is under-engaged, and the other weft threads 12 are over-engaged. At the point of each under-engagement of the base fabric 14, the functional thread 16 forms a corresponding overlying loop 22, followed immediately by another loop 24, resulting in a kind of V-shape. However, other types of weaves are also conceivable, for example, binding the functional thread 16 in a W-shape or the like.

[0022] The aforementioned loops 22, 24 form the closure elements 18 and remain the loops 22, 24 as in Figure 1When closed, a type of fuzzy adhesive fastener is formed. To obtain hook- or mushroom-shaped closure elements 28, the loops 22, 24 on the side are cut open in a ratio of approximately one-third to two-thirds, so that a closure hook 30 is formed. By folding over the top 32 of the base fabric 14 to the underside 26 of the band 8, the closure hooks 30 can engage releasably with lower loop elements 34 of an additionally attached velour 35, which is firmly bonded to the base fabric 14 via an adhesive layer 52 on its underside, preferably made of polyurethane. The adhesive layer 52 partially encloses the contact conductors 38 from the rear and thus forms an electrical insulating layer towards the velour 35. The respective conductor 38 remains free at the top, however, to allow for moisture detection.If the aforementioned separation or cutting process is carried out thermally for the individual loops 22, 24, and in particular the free loop ends are then heated further, the ends shrink and, due to the surface tension of the plastic material, form mushroom-shaped closure heads 36 that protrude on all sides beyond a corresponding stem part 37. It is also possible in this way to create combined closures on the upper surface 32, i.e., closures with hook- and loop-shaped elements on a common side of the base fabric 14. This allows for the attachment of correspondingly designed loop and hook elements of another adhesive closure part of a Velcro® fastener (not shown). For this purpose, not all loops 22, 24 are cut open to form a hook or mushroom head, but remain as loop-shaped engagement material.

[0023] As can be further seen from the Figure 1 In addition to the one functional threads 16 in the form of the individual loops 22, 24, the further functional threads 38 in the form of electrical conductors are introduced as warp threads, which thus run parallel to the warp threads 10 along the rest of the base fabric 14, with each further electrically conductive functional thread 38 alternatingly over or under the respective weft threads 12 and thus being firmly anchored in the base fabric 14.

[0024] How in particular the presentation after the Figure 2 As shown, a single warp thread 10 can also consist of a pair of warp threads or be multi-stranded in some other way. This also applies to the weft threads 12, which, according to the cross-sectional or view representation, are shown in the Figure 2In alternating order, each pair of warp threads 10 is either over- or under-threaded. The respective functional or pile thread 16, skipping one weft thread pair 12 in each instance, over-threads the two following weft thread pairs 12 in the row shown, as well as each electrical conductor as the next functional thread 38.

[0025] The form of volume 8, as shown in the presentation after the Figure 3 prefabricated base fabrics 14 of the Figure 1 Accordingly, along both of its longitudinal edges, the further functional thread 38 is adjacent to each other. This thread is more or less embedded in the base fabric 14 and in any case has exposed areas 40 facing the environment, which can come into contact with moisture that can accumulate on the flexible, non-conductive band 42. Since the band 42 cannot be shown in its entirety, it is, according to the illustration, Figure 3The image is shown interrupted. As can further be seen from the... Figure 3 The free ends of each further functional thread 38 terminate in a contact point 44, to which an evaluation unit is connected. Instead of a connection via solder joints, the contact points 44 can also consist of a socket part into which the evaluation unit can be plugged in using associated connectors (not shown).

[0026] With the aid of a voltage source 48, usually in the form of a DC battery, electric current is passed through the sensor device according to the Figure 3The current is sent via their respective electrical conductors as the further functional threads 38 and with the aid of a display device 50 the measure of the flowing electric current is determined, which is also a measure of the respective humidity that is distributed from the surrounding atmosphere on the band 42 together with its electrical conductors 38 arranged in pairs to each other.

[0027] The ribbon-shaped sensor device according to the Figure 3It can also be used without evaluation unit 46 and, for example, connected to the control unit of a standard household washing machine. With a sensor device attached to the underside of the washing machine, unwanted moisture leakage from the bottom can be detected, and the machine or its water supply can be shut off. For this moisture detection, it has proven advantageous to make the additional functional threads 38 electrically conductive, for example, by using galvanized copper wires, such as those commonly used for conducting electricity.

[0028] Since the band 42 is extremely flexible and can be redirected in a loop-like fashion and releasably attached to third-party components of almost any design, another preferred application would be if such a band 42 were to encompass a socket joint in pipelines in order to detect any potential water leakage in the area of ​​the socket joint. If an evaluation device is then used that enables wireless transmission of measured values, moisture monitoring can be carried out centrally, and several such bands 42 can be monitored simultaneously.

[0029] Furthermore, the special fabric design of the base fabric 14 ensures that the open fabric structure of the tape 42 cannot become saturated with water vapor during operation with the sensor device, which could significantly reduce the measurement sensitivity. Instead, the open fabric structure allows for repeated drying, and the sensor, thus regenerated, is available for further moisture measurements without measurement errors. The fiber material can also be at least partially hydrophobic or coated, thereby removing any residual moisture that would be detrimental to the measurement.

[0030] It goes without saying that the sensor device presented above is only one possible embodiment of a multitude of designs. For example, it would be conceivable to combine several different fabrics, resulting in a wide variety of fabric top surfaces 32 and fabric bottom surfaces 26. Furthermore, it is also possible to obtain the adhesive closure element as a micro-replicated part using a casting process (chill-roll process) and to incorporate the electrical conductors, as well as the additional functional threads 38, at least partially exposed into the casting material.

[0031] Since the band solution after the Figure 3Since the tape can be manufactured in virtually any length, it is also possible to offer it as a retail product without customizing it for a specific application, allowing the customer to freely decide what they actually want to use the sensor device for. This approach has no equivalent in the prior art.

Claims

1. Sensor device for determining moisture using an electrical conductivity measurement, comprising a non-conducting support, wherein the non-conducting support has individual electrical conductors (38), wherein the respective electrical conductor (38) is an integral component of a hook-and-loop fastener part (8) and wherein the electrical resistance between the electrical conductors (38) is dependent upon the amount of moisture present on the support and the electrical conductors (38), characterized in that the hook-and-loop fastener part (8) is made of a base fabric (14), made of warp (10) and weft threads (12), through which passes, at least partially, at least one functional thread (16) which partially forms the fastener elements (18) protruding above the base fabric (14), and in that the electrical conductor is woven into the base fabric (14) as a respective further functional thread (38).

2. Sensor device according to claim 1, characterized by hook elements (30), wherein the hook elements (30) are formed in that the loops (22, 24) of the functional thread (16) are cut open on the side in a ratio of approximately one third to three thirds, wherein terminal thickenings (36) are preferably formed at the free loop ends, which are formed in that the loops (22, 24) are separated thermally and the free loop ends are further heated.

3. Sensor device according to one of claims 1 or 2, characterized in that each further functional thread (38) is woven into the base fabric (14) as a warp thread (10).

4. Sensor device according to one of the preceding claims, characterized in that each further functional thread (38) consists of a non-rusting, multifilament stainless steel yarn.

5. Sensor device according to one of the preceding claims, characterized in that the further functional threads (38) run parallel in associated pairs at a prespecifiable distance from one another in the hook-and-loop fastener part (8).

6. Sensor device according to one of the preceding claims, characterized in that the hook-and-loop fastener part (8) is designed as a flat, flexible strip (42), along whose two longitudinal edges a further functional thread (38) runs over the entire strip length in each case.

7. Sensor device according to one of the preceding claims, characterized in that the electrically-conductive further functional threads (38) are firmly bonded on the rear side to a non-conductive polyurethane layer (52), which preferably adjoins a surface adhesion part (35), which is fixedly connected to this layer (52).

8. Sensor device according to claim 7, wherein the surface adhesion part (35) forms an again releasable hook-and-loop fastener with the fastener elements (18) of the hook-and-loop fastener part (8).

9. Sensor device according to one of the preceding claims, characterized in that electrical contacting points (44) are applied or incorporated into the strip-like hook-and-loop fastener part (8), in which the respective further functional thread (38) ends.

10. Sensor device according to one of the preceding claims, characterized in that an evaluation device (46) for the measurement data is connected to the respective further functional thread (38).