DE102020133903A1 - Sensor device and method for detecting the presence of media using a sensor device - Google Patents

Abstract

A sensor device (500) and a method for detecting the presence of media using a sensor device (500) are described, the sensor device (500) having at least one sensor film (100), the sensor film (100) having at least a first electrically conductive Layer (130) and a second electrically conductive layer (150), wherein at least one insulating layer (110) made of electrically non-conductive material is arranged between the first electrically conductive layer (130) and the second electrically conductive layer (150). The sensor film (100) has openings (170) that run through the first electrically conductive layer (130), the second electrically conductive layer (150) and the at least one insulating layer (110), each of the openings (170) being related on the first electrically conductive layer (130), the second electrically conductive layer (150) and the at least one insulating layer (110) spans an equally large free area, and wherein the layer thickness of the at least one insulating layer (110) is greater than the layer thickness in each case of the first electrically conductive layer (130) and the layer thickness of the second electrically conductive layer (150).

Description

What is described and claimed herein relates to a sensor device and a method for detecting the presence of media using a sensor device. Media can be liquids or fine-grained solids, for example.

To detect the presence of media, such as water or another liquid, sensor devices are used which have sensor foils that are connected to an evaluation circuit. The sensor foils have openings into which liquid can penetrate, the sensor foils comprising a layer structure with two electrically conductive layers which are separated from one another by an insulating spacer layer. When liquid enters the openings, a short circuit occurs between the electrically conductive layers, which leads to a change in resistance that can be detected by the evaluation circuit. In this way, for example, leaks can be detected.

Such sensor devices can be provided, for example, on roofs, in sanitary areas (for example bathrooms), in industrial plants, etc. for monitoring in order to determine the escape of liquids or other media, such as fine-grained solids.

A frequent problem with sensor devices with a sensor film, which have separate electrode layers via a spacer layer or insulation layer, is that a short circuit can be generated, for example, when openings are made to accommodate the liquids to be detected or the like, or when the sensor film is “cut to size”. , which results from the fact that the two electrode layers are brought into contact with each other when the openings are made or when the foil is "cut to size". Of course, the short circuit only occurs when a voltage is applied to the sensor foil.

From the state of the art this is out EP 2 844 972 B1 a leak detector is known which has a sensor film which has a carrier film and conductive electrode films arranged on both sides of the carrier film. In this case, an upper first conductive electrode foil has circular openings in a pattern which have a larger diameter than concentric openings in the carrier foil and the second conductive electrode foil arranged underneath. The corresponding openings in the carrier foil and the second conductive electrode foil are produced by punching. Since a short circuit may occur between the first conductive electrode sheet and the second conductive electrode sheet during punching, a short circuit at the in EP 2 844 972 B1 described sensor film is prevented on the one hand by the fact that the openings in the first conductive electrode foil are produced by means of etching and on the other hand the openings in the carrier foil and the second conductive electrode foil are smaller than the openings in the first electrode foil.

the inside EP 2 844 972 B1 However, the layer structure described and the method for producing the sensor film have significant disadvantages. For example, due to the smaller opening in the carrier film, drops that do not reach the second conductive electrode film located underneath can be held, so that no reliable detection of leaks can take place.

Furthermore, the known prior art has the disadvantage that two different methods have to be carried out to produce the openings. In addition, it is fundamentally not possible to produce both openings with different diameters in one work step. Therefore, the cost of producing a film is significantly increased.

Furthermore, the sensor area of the sensor film from the prior art is relatively small compared to the area of the sensor film, which makes it difficult to detect leaks.

An object of an embodiment according to the invention can therefore be to create a possibility that allows a simple layer structure for a sensor film that is easy to produce, a relatively large sensor area can be provided and the dimensions of the sensor film can be easily changed without, among other things, contacting of a first electrically conductive layer and a second electrically conductive layer is produced, which would cause a short circuit.

Furthermore, a method is to be made possible with which a sensor device can be operated and which allow reliable detection of the presence of a medium.

• - die Sensorfolie Öffnungen aufweist, die durch die erste elektrisch leitende Schicht, die zweite elektrisch leitende Schicht und die mindestens eine Isolationsschicht verlaufen,
• - jede der Öffnungen in Bezug auf die erste elektrisch leitende Schicht, die zweite elektrisch leitende Schicht und die mindestens eine Isolationsschicht eine gleich große freie Fläche aufspannt, und
• - die Schichtdicke der mindestens einen Isolationsschicht jeweils größer ist als die Schichtdicke der ersten elektrisch leitenden Schicht und die Schichtdicke der zweiten elektrisch leitenden Schicht.

According to one aspect, such an embodiment of the invention relates, at least in a core idea, to a sensor device for detecting the presence of a medium, comprising: at least one sensor film, the sensor film having at least a first electrically conductive layer and a second electrically conductive layer, with between the first electrically conductive Layer and the second electrically conductive Layer at least one insulation layer made of electrically non-conductive material is arranged, wherein

• - the sensor film has openings that run through the first electrically conductive layer, the second electrically conductive layer and the at least one insulating layer,
• - each of the openings spans an equally large free area in relation to the first electrically conductive layer, the second electrically conductive layer and the at least one insulating layer, and
• - The layer thickness of the at least one insulation layer is greater than the layer thickness of the first electrically conductive layer and the layer thickness of the second electrically conductive layer.

The structure of the sensor film of the sensor device is characterized in that the layer thickness of the at least one insulating layer is greater than the layer thickness of the first electrically conductive layer and the layer thickness of the second electrically conductive layer. This ensures that even when the openings are made in the sensor foil and when the sensor foil is "cut to size", no contact can be made between the two electrically conductive layers via the insulating layer. It is therefore not possible for regions of the first electrically conductive layer and/or the second electrically conductive layer to come into contact with the respective other electrically conductive layer via the insulating layer.

The use of appropriate layers (insulation layer, electrically conductive layers) with the layer thicknesses matched to one another therefore allows the sensor film to be adapted to local conditions using simple means such as scissors. Furthermore, the production of the sensor film is easy to implement because, for example, punching tools can be used which make the openings in the sensor film, with the openings being produced all at once through the sensor film. This also ensures that the opening width of the openings in the individual layers of the sensor film is the same and that the openings in the individual layers are congruent, so that no drops of liquid or the like of a medium stick to edges of different sizes or slightly offset from one another Openings within the layer structure comes.

The presence of a medium, such as a liquid, is detected by a drop of liquid getting into the opening and then creating a short circuit or at least a measurable reduction in the electrical resistance between the first electrically conductive layer and the second electrically conductive layer, which via a Evaluation circuit is detected. Due to the above-described mode of operation, when short-circuiting is mentioned here in connection with the invention, the already mentioned measurable reduction in electrical resistance is also meant.

For this purpose, the electrically conductive layers consist, for example, of an electrically conductive metal (e.g. aluminum, copper, brass, stainless steel, gold and other metals) or an electrically conductive plastic, with carbon being introduced into a plastic for conductivity, for example.

Depending on the medium to be monitored and the environment in which the sensor device is used, chemically stable metals can be used accordingly, for example in a chemically aggressive environment or a chemically aggressive medium.

In further versions, the openings in the sensor film can be stretched. "Elongated" means that the openings are not circular as in the prior art. The sensor foil therefore has no circular openings. Elongated openings are therefore, for example, elongated openings and oval openings, with the openings being rounded off at their ends so that there are no sharp edges in the openings, which on the one hand form starting points for a tear in the sensor film and on the other hand also allow droplets of a medium to adhere that could make it difficult or impossible to detect the presence of a medium. Elongated openings can extend in one direction or be curved once or multiple times. Exemplary shapes include but are not limited to a substantially C-, S-, or bracket-like arch shape. In further versions, the openings can also have, for example, a T-shape with rounded edges/corners.

In further embodiments, differently designed openings can also be provided in the sensor film. The openings can form a pattern.

It is essential that the sensor area is enlarged compared to circular openings due to the design of the openings. The sensor area of an opening in the sensor film is the distance between the electrically conductive layers plus the respective material thickness of the electrically conductive layers multiplied by the length/circumference of the opening. The effective sensor area of the sensor foil is consequently the sum of these areas in the openings.

In comparison, the remaining surface area of the sensor foil should be minimized in order to optimize the detection accuracy of a medium that is present, whereby, depending on the application, the mechanical stability or a minimum of mechanical stability or a minimum of the mechanical stability that is still necessary should be maintained, which ultimately leads to Enlargement or maximization of the sensor surface leads and, in order to improve the sensitivity of the sensor device, in particular includes or includes a maximization of the number of openings in the sensor film.

The formation of the openings also depends on the medium from which the presence is to be detected. For example, different liquids form droplets of different sizes. The opening width of the openings can then also be determined with this. In addition, the distance between the openings in the sensor film can also depend on the medium whose presence is to be detected. In other embodiments, the distance from adjacent openings in the sensor film can essentially only ever be as large as the average droplet size of a specific liquid.

In further embodiments, a protective layer made of an electrically non-conductive material is arranged on the first electrically conductive layer and/or the second electrically conductive layer. This layer can consist of a non-conductive plastic, for example, which has chemical resistance to the environment and/or a corresponding medium, for example. In further embodiments, the at least one protective layer can be connected to the electrically conductive layers in a slightly adhering or adhesive manner.

In order to contact the sensor film with a corresponding device, it is necessary in further embodiments for the protective layer to be partially removed at the contact point. If a protective layer is connected to the first electrically conductive layer and/or the second electrically conductive layer, an adhesive bond can be removed by thermal or mechanical influence, for example. In the case of an adhesive connection between the protective layer and an associated first or second electrically conductive layer, the protective layer can simply be pulled off and, for example, cut into.

In further embodiments, the protective layer on the first electrically conductive layer and/or the protective layer on the second electrically conductive layer has openings corresponding to the openings in the first electrically conductive layer, the second electrically conductive layer and the at least one insulating layer. The openings can be introduced together with the openings in the first electrically conductive layer, the insulating layer and the second electrically conductive layer. Alternatively, it is also possible to apply at least one protective layer with openings already provided to a prefabricated sensor film with corresponding openings, or to connect at least one protective layer or a sensor film blank, with either the at least one protective layer or the sensor film blank having openings, and then to cut the openings into the to introduce the other part in each case, with the existing openings in the other part serving for orientation or as a template for aligning and introducing openings.

In further embodiments, for example, a protective layer arranged on an underside of the sensor film can have no openings. Such designs can be used, for example, in areas where condensation of humidity does not occur or is unlikely to occur, e.g. in the bathroom (shower, bathtub, etc.). Leakage liquid as the medium to be detected would then collect in the openings, with the lower protective layer preventing leakage liquid from penetrating. A leak can thus be detected and the substrate of the sensor foil is protected from leaking liquid.

In further embodiments, a first insulation layer and a second insulation layer are provided, with at least one reinforcement layer being arranged between the first insulation layer and the second insulation layer and the first insulation layer being connected to the first electrically conductive layer and the second insulation layer being connected to the second electrically conductive layer, wherein the first insulating layer, the second insulating layer and the reinforcing layer have corresponding openings to the openings in the first electrically conductive layer and the second electrically conductive layer. Since the insulation layer can be made of plastic and is therefore sensitive to high loads, the sensor film can be reinforced by the reinforcement layer. High mechanical loads can arise, for example, because the sensor foil has to bear its own weight over a long distance or is stretched without being supported by the substrate. In the case of high forces parallel to the film plane of the sensor film, the insulation layer could stretch, which could cause cracks in the electrically conductive layers, which could even lead to inoperability. The reinforcement layer, for example made of a strong, poorly stretchable material, preferably made of metal, eg a stainless steel foil, introduces a fuse into the sensor foil. In addition, two insulation layers are then required, which can be glued to the reinforcement layer, for example. In these embodiments, it is essential that both insulation layers each have a greater layer thickness than the electrically conductive layers provided in each case, so that when openings are made in the sensor film or when the sensor film is cut to size, there is no undesired contact between the electrically conductive layers and the metal existing reinforcement layer occurs.

In further embodiments, at least one outer layer of the sensor film has a hydrophobic and/or oleophobic coating. The outer layers can be, for example, the first and/or second electrically conductive layer or the protective layers on the corresponding electrically conductive layers. The hydrophobic and/or oleophobic coating has the advantage that drops of a corresponding liquid, such as water or oil or a liquid containing water or oil, that strike the surface of the sensor film are forced into the openings due to the coating, so that a reliable Detection of the presence of a corresponding liquid can be achieved. In particular, it is thus possible, for example, for each drop that strikes the sensor film to be forced into a corresponding opening, so that a leak can be detected immediately. For this it is also advantageous if the distance between the openings is as small as possible, preferably not larger than the average droplet diameter of the respective liquid.

In further embodiments, the sensor device has an evaluation unit which is connected to the electrically conductive layers of the sensor film, so that the presence of media can be detected. For this purpose, for example, a voltage can be applied to the two electrically conductive layers via the evaluation unit.

In further embodiments, the sensor device has a contact unit, which has a housing in which two opposing contacts are accommodated, which are each connected to one of the two electrically conductive layers, the contacts each being connectable to an electrical line. The sensor foil is contacted via the contact unit. A connection can thus be established between the sensor film and an evaluation unit, with electrical lines extending from the housing and the contacts to the evaluation unit.

In further versions, the housing is designed in two parts and has a latching mechanism, by means of which the contacts can be pressed against the electrically conductive layers via the housing. The locking mechanism ensures that after the contacts of the contact unit have been connected to the corresponding electrically conductive layers, the contact pressure of the contacts on the electrically conductive layers is maintained. The housing can have at least one elevation or another clamping device in the area of the opposing contacts, which provides protection against the sensor film being pulled out of the housing of the contact unit or the contact unit being pulled off the sensor film.

In further embodiments, the sensor device has a plurality of first webs of sensor films running parallel and spaced apart from one another and a plurality of second webs of sensor films running parallel and spaced apart from one another, the first webs and the second webs being arranged one above the other in a different orientation from one another and each individual web having is connected to a common evaluation unit. This enables localization of an area where the presence of a medium occurs. The first webs and second webs can be arranged in such a way that the openings of the first webs run substantially congruently with the openings of the second webs. Congruent does not mean that the openings have to lie exactly on top of each other, since this is the case, for example, with C-shaped or otherwise formed elongated openings in first webs in a first direction and correspondingly formed openings in second webs in a second direction, which, for example, runs orthogonally to the first direction , is not always possible. It is essential that the openings in the first and second webs, which are arranged congruently with one another, lie one above the other in a central region of the openings, so that, for example, a liquid droplet of a medium can pass both through an opening in one of the first webs and then into an opening in one of the second webs and thus creates a short circuit in the two tracks, which is detected by the common evaluation unit. The position of the drop in an area can then be determined using the information obtained. In this case, the first tracks and the second tracks must also be electrically insulated from one another, so that a short circuit does not occur between the first tracks and the second tracks. In further embodiments, the sensor foils can also be designed in this way be chosen so that even with an orthogonal or other arrangement of the first and second webs, the openings are aligned congruently with one another and lie on top of one another.

Such an arrangement can have, for example, a matrix arrangement, with the first and second tracks running perpendicular to one another in one area.

The width of the respective webs or sensor foils is decisive for the fineness in relation to the point at which a liquid drop occurs. I.e. the smaller the width of the tracks, the more precisely a stepping point can be determined.

In further embodiments, the first webs of sensor films and the second webs of sensor films are separated from one another by at least one spacer layer and/or at least the first webs of sensor films are separated from a substrate by at least one spacer layer. The spacer layer between the first tracks of sensor foils and the second tracks of sensor foils prevents a short circuit from occurring between them. A spacer layer between the first webs of sensor foils and a substrate prevents, for example, chemical reactions of the substrate with the sensor foil. For example, concrete is highly alkaline and capable of chemical changes. An effect on the sensor foil can thus be avoided via a spacer layer. The at least one spacer layer can be designed as a net, for example, and have a relatively large mesh size. The mesh size is to be designed for the static and dynamic forces acting on the entire arrangement. Care must also be taken to ensure that no large "air pockets" exist or sink marks are generated when such an arrangement is installed. The spacer layer may consist of a mesh or Mesh fabrics are formed, such as is used in the construction industry.

In further versions, the layer thickness of the at least one insulation layer is at least 6 times greater than the layer thickness of the at least one first electrically conductive layer and the layer thickness of the at least one second electrically conductive layer. Such a ratio of the respective layer thicknesses to one another ensures, for example in the case of a material pairing of polyethylene terephthalate (PET) as an insulating layer and electrically conductive layers made of metal (e.g. aluminium), that no short circuit occurs, regardless of the method used to make the openings and to "cut" the sensor foil is generated or may occur.

Particularly suitable methods for “cutting” the sensor foil or making openings include, for example, processing using a laser or water jet. However, the specified layer thickness of the at least one insulating layer compared to the electrically conductive layers ensures that no electrical short circuits can occur due to shearing forces, even when openings are made by punching and when the sensor films are cut.

Another aspect of the invention also relates to an embodiment in terms of a method for detecting the presence of media using one of the sensor devices described above, wherein a voltage is applied to the two electrically conductive layers via an evaluation unit, and wherein a change in voltage due to the presence of a medium in the area of an opening is recognized by the evaluation unit as the presence of the medium and a response to the presence is output.

The method relates to a resistance measurement in the form of a voltage divider, with a measurement voltage being applied to an electrically conductive layer via a high-impedance series resistor, which is part of the evaluation electronics of the evaluation unit, with a voltage divider being formed from the high-impedance series resistor and the resistance between the electrically conductive layers . The second electrically conductive layer that is not connected to the series resistor is connected by the evaluation electronics to ground or mass potential, which corresponds to the negative pole of the measurement voltage. Due to the extremely high resistance of the insulation layer, the measurement voltage is therefore approximately measured in the absence of, for example, a leaking liquid or another medium in at least one of the openings. If the sensor surface of the openings is touched by leakage liquid, the resistance between the electrically conductive layers and thus the medium voltage of the voltage divider decreases. The evaluation electronics can measure this voltage continuously with an AD converter or compare it with an analogue circuit using a comparator. If the mean voltage of the voltage divider falls below a definable value, the presence of a leaking liquid or a medium in the openings is detected. The evaluation unit can then issue messages or initiate measures such as closing valves or switching off pumps, conveyors, etc.

In further versions, the voltage is measured at the electrically conductive layers at definable intervals and the current direction is reversed after each measurement in order to avoid electrolysis effects on the electrically conductive layers. In addition, electrolysis effects of the contacts of contact units can also be largely avoided in this way. The result of this is that the sensor device can be operated over a long period of time without erroneous measurement results or a failure occurring.

The direction of measurement can be reversed very slowly, e.g. in the range of several seconds, so that there is an ohmic resistance measurement.

If the switching frequency is greatly increased, e.g. in a range of several hundred Hertz, an impedance measurement occurs. This allows the measurement to be adapted to different liquids as media and their electrical properties.

In addition, according to one embodiment, the sensor device and the method according to the invention are designed and set up such that the contacting or contacting quality between the contacts with the respective electrically conductive layers can be verified in a further testing process. Here, a test current is routed from the evaluation electronics via a first connection cable to the first contact, on to the layer assigned to it, to the second contact and from there via a second connection cable back to the evaluation electronics, which means that unwanted resistances, for example, can be detected.

Furthermore, according to the invention, the application of a cleaning current can be provided in such a way that, for example, a resistance-forming oxidative insulating layer between the contacts and conductive layers can be loosened or removed.

Further features, advantages, effects and details result from the following description, in which at least one exemplary embodiment is described in detail, if appropriate with reference to one or more drawings. Described and/or illustrated features form the subject matter alone or in any meaningful combination, possibly also independently of the claims, and in particular can also be the subject matter of one or more separate applications. Identical, similar and/or functionally identical parts are provided with the same reference symbols.

In addition, there is no need to show and describe components that are not essential for understanding the technical teaching disclosed herein. In the following, the reference symbols are not repeated for all elements that have already been introduced and shown, provided that the elements themselves and their function have already been described or are known to a person skilled in the art. Information relating to the erection and arrangement of components relate to the exemplary embodiments shown and are not to be understood as limiting.

• 1 einen Schichtaufbau einer Sensorfolie in einer ersten Ausführungsform;
• 2 einen Schichtaufbau einer Sensorfolie in einer zweiten Ausführungsform;
• 3 verschiedene Ausbildungen und Anordnungen von Öffnungen in einer Sensorfolie;
• 4 das Messprinzip einer Sensoreinrichtung;
• 5 schematische Darstellungen von Abstandsschichten;
• 6 einen Schichtaufbau einer Sensoreinrichtung mit mehreren ersten und zweiten Bahnen von Sensorfolien und Abstandsschichten;
• 7 eine schematische Darstellung einer Sensoreinrichtung mit mehreren ersten und zweiten Bahnen von Sensorfolien in einer Matrixstruktur;
• 8 ein Ablaufdiagramm einer Auswerteeinheit zum Betreiben einer Sensoreinrichtung;
• 9 verschiedene Darstellungen von Bestandteilen für die Kontaktierung einer Sensorfolie;
• 10 schematische Darstellung des Aufbaus einer Auswerteeinheit und
• 11 verschiedene Darstellungen einer Kontakteinheit für die Kontaktierung einer Sensorfolie.

Schematically show:

• 1 a layer structure of a sensor film in a first embodiment;
• 2 a layer structure of a sensor film in a second embodiment;
• 3 various configurations and arrangements of openings in a sensor film;
• 4 the measuring principle of a sensor device;
• 5 schematic representations of spacer layers;
• 6 a layer structure of a sensor device with a plurality of first and second webs of sensor foils and spacer layers;
• 7 a schematic representation of a sensor device with a plurality of first and second webs of sensor foils in a matrix structure;
• 8th a flowchart of an evaluation unit for operating a sensor device;
• 9 various representations of components for contacting a sensor film;
• 10 schematic representation of the structure of an evaluation unit and
• 11 different representations of a contact unit for contacting a sensor foil.

The figures describe embodiments of sensor devices 500 and components thereof that are provided for detecting leaks. In this case, the presence of a leaking liquid is determined via the sensor devices 500 . Such sensor devices 500 can be used, for example, to detect leaking liquid in various areas, such as in showers, bathtubs, washing machines, dishwashers, pipes (drain, inflow, etc.) and roofs of all types. Furthermore, the sensor devices 500 can be provided to protect rooms in which sensitive devices are housed (protection of IT equipment). But it can also be used to monitor industrial plants. For example, the escape of dangerous (poisonous) or highly flammable liquids can be detected immediately and appropriate measures can be taken after detection.

Compared to leak detection, the detection of leaking liquid is simultaneous with its presence. Damage can therefore be prevented at an early stage if a corresponding detection of the presence of leaking liquid takes place. In an exemplary embodiment with a matrix arrangement of sensor foils 100, it is possible to restrict the detection of leaks to a small area in the case of large areas, which further reduces the effort and saves costs.

An essential component of the sensor devices 500 is in each case at least one sensor film 100 which can be connected or is connected to an evaluation unit 400 via a contact unit 300 .

1 shows a layer structure of a sensor film 100 in a first embodiment.

Sensor film 100 has a first electrically conductive layer 130 and a second electrically conductive layer 150, with first electrically conductive layer 130 being an upper layer and second electrically conductive layer 150 being a lower layer of the layer structure of sensor film 100 shown in the embodiments shown . The electrically conductive layers 130, 150 function as electrodes in the sensor film 100. An insulating layer 110 is arranged between the electrically conductive layers 130 , 150 . In addition, protective layers 140 , 160 are provided on the top and bottom of sensor film 100 , protective layer 140 being applied to first electrically conductive layer 130 and protective layer 160 to second electrically conductive layer 150 .

In further specific embodiments that are not shown, a sensor film 100 can also have a layer structure without the protective layers 140 , 160 .

In the embodiments shown, the electrically conductive layers 130, 150 consist of a metal foil. For example, the metal foil may be aluminum 10-100 microns thick.

Depending on the ambient conditions and the leakage liquid, other metals, such as copper, brass, stainless steel, gold and other metals, or other materials can also be used as the electrode material for the electrically conductive layers 130, 150. In the case of a chemically aggressive environment or chemically aggressive leakage liquid, chemically more stable metals can be used accordingly.

Furthermore, the first electrically conductive layer 130 and the second electrically conductive layer 150 can consist of different metals or materials.

In further embodiments, the electrically conductive layers 130, 150 can also consist of conductive plastic to which, for example, carbon has been added for conductivity or is conductive due to its properties.

The insulating layer 110 consists of electrically non-conductive plastic such as PET.

The layers of the layer structure of the sensor film 100, namely the insulation layer 110, the electrically conductive layers 130, 150 and the protective layers 140, 160 can be glued together.

The protective layers 140, 160 are electrically non-conductive and may be made of a non-conductive plastic, which may also have chemical resistance to the environment and spill fluid. In further embodiments, the protective layers 140, 160 can be lightly adhesively bonded to the electrically conductive layers 130, 150. In this case, the protective layers 140, 160 must later be partially removed at the contact point of the sensor film 100. In the case of an adhesive bond, this can happen, for example, due to thermal or mechanical influences.

The sensor foils 100 are correspondingly designed in such a way that the individual layers extend over the entire width and length of the sensor foils 100 . The sensor foils 100 can essentially be of any length in relation to their length. Depending on the required length, the sensor foil 100 can be cut to length, for example (for example using scissors or the like). After cutting to length, the contact is made, for which a contact unit 300 (see 9 and 11 ) can be connected to the sensor film 100. The width of the sensor foils 100 can be provided in specific dimensions. It is also possible here to make an adjustment by cutting or the like. In a matrix arrangement, the width of sensor foils 100 determines the fineness with which leaks can be detected (see 6 and 7 ).

2 shows a layer structure of a sensor film 100 in a second embodiment.

With very high mechanical loads on the sensor film 100, the structure can 1 be insufficient because an insulating layer 110 made of plastic cannot absorb high loads. High mechanical loads can arise, for example, because the sensor film 100 has to bear its own weight over a long distance or is stretched without the sensor film 100 being supported by the substrate. With high forces parallel to the film plane of the sensor film 100, the insulation layer 110 of the sensor film 100 would 1 stretch. As a result, cracks can form in the electrically conductive layers 130, 150, which can go as far as making them inoperable.

the inside 2 The layer structure of the sensor film 100 shown in a second embodiment offers a solution for sensor films 100 that are exposed to high loads.

For this purpose, the layer structure for the sensor film 100 of the second embodiment 2 a reinforcement layer 120 on. The reinforcement layer 120 consists of a tensile, poorly or non-extensible material. For this purpose, the reinforcing layer 120 can consist of metal, for example a stainless steel foil. The reinforcement layer 120 can thus be electrically conductive, so that an insulation layer 112, 114 is applied to the reinforcement layer 120 on both sides (top side and bottom side). A first insulating layer 112 may be applied to the top of the reinforcement layer 110 and a second insulating layer 114 may be applied to the underside of the reinforcement layer 110 . For this purpose, the insulation layers 112, 114 can be glued to the reinforcement layer 110, for example.

The insulation layers 112, 114 can consist of the same material as the insulation layer 110. In the second embodiment, the electrically conductive layers 130, 150 can be glued to the insulation layers 112, 114 like the electrically conductive layers 130, 150 of the first embodiment.

To detect the presence of a leaking liquid, the sensor foils 100 have openings 170 which extend through the layer structure and provide a short circuit between the two electrodes, formed by the electrically conductive layers 130, 150, when a drop of leaking liquid falls into the openings 170 reached.

So that the sensor foils 100 have sensor properties, structures in the form of continuous openings 170 are introduced. The openings 170 can, for example, be introduced mechanically, for example by punching, or with the aid of lasers or a water jet. The sensor films 100 must be processed in such a way that the electrically conductive layers 130, 150 and possibly also a reinforcement layer 120 are not in contact with one another after processing, since they would otherwise cause an undesirable electrical short circuit. During punching and cutting, this could occur due to shearing forces.

The relative material thickness of the electrically conductive layers 130, 150 (or reinforcing layer 120) and the insulating layer 110 (or insulating layers 112, 114) is matched to one another so that undesired (false) short circuits do not occur. The relative layer thickness of the insulation layers 110, 112, 114 is at least twice as large as the layer thickness of the electrically conductive layers 130, 150 or the reinforcement layer 120.

In versions with an insulation layer 110 made of PET, for example, the layer thickness is six times greater than the layer thickness of the electrically conductive layers 130, 150 made of aluminum, for example. This ensures that the cut electrically conductive layers 130, 150 do not have any electrical contact during processing with simple mechanical means, such as commercially available scissors.

The material thickness or layer thickness of the insulation layer 110 must also be chosen such that it has sufficient mechanical stability for the corresponding application with openings 170 .

Due to the structure described, the sensor film 100 can therefore advantageously be severed in any form during installation using simple mechanical means, such as scissors, and can thus be adapted to the respective local conditions. In addition, sections can be removed in order to adapt the sensor film 100 to the spatial conditions in order to avoid, for example, spatial obstacles 600 (see, for example, 7 ). The functionality is always given. Even regional cracks in the electrically conductive layers 130, 150, which do not extend over the entire width of the sensor film 100, have no effect on the functionality. Cracks in the electrically conductive layers 130, 150, which extend over the entire length or width of a sensor film 100, would divide the respective electrically conductive layer 130, 150. In this case, the section of the electrically conductive layer 130, 150 that is contacted would still be functional, and the other section would not. Is the electrically conductive layer 130, 150 in at least a small portion of the width or length of the sensor pad If 100 is not torn, there is an electrical connection with the rest and thus the entire electrically conductive layer 130, 150 is functional.

In 3 Various configurations and arrangements of openings 170 in sensor foils 100 are shown.

Examples of possible forms of openings 170 are shown in 3a) shown. Depending on the leakage liquid and the physical conditions, the width of an opening 170 should be selected such that the smallest drop that occurs cannot fall through the opening 170 without touching the two electrically conductive layers 130, 150 in order to create a short circuit. With water as the leakage liquid, the width of an opening 170 can therefore be between 2-6 mm, preferably between 3-4 mm. A round opening is to be avoided because a drop of leakage liquid can be held by the sensor film 100 from all sides and the drop is thus prevented from flowing through. In the 3a) forms shown therefore have an elongated shape, which preferably have a length of at least twice the width. Furthermore, corners in the openings 170 are rounded off as far as possible in order to make the sensor film 100 more stable and to avoid cracks.

3b) and c ) show different arrangement possibilities of the openings 170. The different forms from 3a) can also be combined with each other. It is also possible to combine shapes of different sizes or widths. The aim of the arrangement of the openings 170 is to achieve the smallest possible residual surface of the sensor film 100 in order to maximize the sensitive area of the sensor film 100 so that the smallest amounts of leaking liquid can be reliably detected. The stability of the sensor film 100 counteracts this. The arrangement of the openings 100 must therefore also be selected in each case in such a way that the sensor film 100 has sufficient stability.

Since the leakage liquid reduces the resistance between the electrically conductive layers 130, 150, the effective sensor area of an opening 170 of the sensor film 100 is the distance between the electrically conductive layers 130, 150 plus the respective material thickness (layer thickness) of the electrically conductive layers 130, 150 multiplied with the length/circumference of the opening 170. The effective sensor area of the sensor film 100 is consequently the sum of these areas in the openings 170. The remaining surface area of the sensor film 100 is primarily used for mechanical stability and makes no contribution to determining the presence of leaking liquid. In order to obtain as much sensor area as possible, as many openings 170 as possible are made in sensor foils 100 . The smaller the remaining residual surface of the sensor film 100, the more likely it is that a single drop of leaking liquid will be reliably detected by evaluation electronics 410 of an evaluation unit 400. Furthermore, this reduces the distance to the sensor surface for the leakage liquid.

For this purpose, for example, the greatest distance from opening 170 to opening 170 of the sensor film 100 can be 4 mm. If a drop of spherical leakage liquid with a diameter of 4 mm falls on the sensor surface, in the worst case it will hit the ball in such a way that the diameter of the sphere is at the greatest distance from the openings 170 . Due to gravity and impact, the drop on the sensor sheet 100 flattens out and widens. The remaining kinetic energy causes the drop to move. If the drop touches the electrically conductive layers 130, 150, the leaking liquid is recognized by the evaluation electronics 410. If the drop of leakage liquid partially falls onto an opening 170 in the sensor film 100, the drop is reliably detected by the evaluation electronics 410. A movement of the leakage liquid on the sensor film 100 can be forced, for example, by the sensor film 100 having a slight incline. For this purpose, the sensor film 100 must be arranged accordingly on a substrate or an arrangement underneath.

Another method is to coat the respective top layer (e.g. protective layer 140) with a substance that repels leaking liquid, e.g. a hydrophobic or oleophobic coating. Furthermore, the upper protective layer 140 can also have such properties.

The remaining area of the sensor foil 100 and the number and shape of the openings 170 determine the stability and tear resistance of the sensor foil 100. For large areas, e.g. roofs, the foil stability of the sensor foil 100 plays a major role during installation. Thus, the maximum sensor surface and the stability of the sensor foil 100 can always be adapted to the respective application.

For the determination of leakage liquid it is important that even the smallest amounts of leakage liquid can penetrate the sensor foil 100 in the openings 170 . For the arrangement of a sensor device 500 in a matrix structure (see 6 , 7 ) the ability to penetrate the openings 170 is essential so that a short circuit can be generated by a drop in two sensor films 100 that are oriented differently from one another and are arranged one above the other.

In further embodiments, a sensor film 100 can be designed in such a way that the lower protective layer 160 has no openings 170 . Such a sensor film 100 can be used in areas in which little or no condensation of atmospheric moisture occurs, such as under a shower or bathtub in the bathroom. With such a sensor film 100, the leakage liquid can collect in the openings 170, with the lower protective layer 160 preventing the leakage liquid from penetrating. With such an embodiment, a leak can be detected and the substrate of the sensor film 100 can be protected from the leaking liquid.

The measuring principle used to measure the leakage liquid is shown 4 . This is a resistance measurement in the form of a voltage divider. In this case, R1 corresponds to the high-impedance series resistor that is located on evaluation electronics 410. The value of R1 is between 100-1000 kΩ depending on the leakage liquid whose presence is to be monitored. By applying a measuring voltage UM via the series resistor R1 to one of the electrically conductive layers 130, 150, a voltage divider is created consisting of the high-impedance resistor R1 and the resistor R2 between the electrically conductive layers 130, 150. The second electrically conductive layer that is not connected to the series resistor Layer 150 is connected by evaluation electronics 410 to the ground potential, which corresponds to the negative pole of measurement voltage UM. Due to the extremely high resistance of the insulation layer 110 due to its properties and layer thickness, the measuring voltage UM is measured approximately in the absence of leakage liquid. If the sensor surface (Z-axis of the openings 170) is touched by leakage liquid, the resistance between the electrically conductive layers 130, 150 and thus the mean voltage of the voltage divider decreases. The evaluation electronics 410 can measure this voltage continuously with an AD converter or compare it with an analog circuit with a comparator. If the mean voltage of the voltage divider falls below a specific, definable value, the evaluation unit 400 detects the presence of leaking liquid and outputs a corresponding output via at least one unit connected to an interface unit 440 .

In order to largely avoid electrolysis effects in the electrically conductive layers 130, 150 and the contacts 320, the current direction is reversed after each measurement (see Fig 8th ). The direction of measurement is reversed very slowly, for example in the range of several seconds, so that an ohmic resistance measurement is available.

Out of 8th shows that the measurement direction is changed after each measurement. If the switching frequency is greatly increased, eg in the range of several hundred Hertz, an impedance measurement occurs. The evaluation unit 400 can thus be adapted to different leakage liquids and their electrical properties. This allows the range of use to be increased by adjusting the controls. For example, an evaluation unit 400 can be adapted to different areas of use and liquids to be monitored. However, it is also possible to monitor the presence of several different liquids, with the frequency being changed at regular intervals.

5 shows schematic representations of spacer layers 200 for a sensor device 500 with a plurality of sensor films 100, as in an exemplary embodiment in FIGS 6 and 7 is shown.

For local delimitation when detecting leaking liquid and for determining leaks in large areas, it is possible to lay several sensor foils 100 in a matrix arrangement and thus limit the area of the leak to a specific smaller area.

In a large number of applications, sensor foils 100 should not be placed directly on a substrate, for example in order to avoid chemical reactions between the substrate of sensor foil 100 . For example, concrete is highly alkaline and capable of causing chemical changes in sensor foils 100 having a construction as described herein. In order to prevent the substrate from having any effect on the sensor foils 100, a spacer layer 200, for example in the form of a network structure, as is shown in 5 shown in two different configurations, to be laid on a substrate. Spacer layers 200 with a network structure can consist, for example, of commercially available mesh or grid fabric, as is used in the construction industry. Instead of a net-like spacer layer 200 between a substrate and a sensor film 100, however, spacer layers 200 of a different design can also be laid. However, in the case of spacer layers 200 described further between two layers of sensor films 100, it is essential that these spacer layers 200 have openings which allow leakage liquid to pass through in the Z-direction.

When forming a matrix structure for the sensor device 500, after the arrangement or laying of a spacer layer 200, several strips of sensor foils 100 are laid.

the 6 and 7 show the structure schematically. 6 shows a layered structure of a sensor device 500 with a plurality of first and second webs of sensor foils 100 and spacer layers 200. 7 shows a further representation of the sensor device of FIG 6 .

First, a spacer layer 200 is laid on the ground. For the sensor device 500, the area to be monitored is then laid, e.g. in the X direction, with several strips of sensor foils 100. Each individual web is connected to the evaluation electronics 410 of the evaluation unit 400 at one end. The individual webs of sensor foils 100 must not touch one another. This can be achieved, for example, with insulating adhesive tape or spacers.

The webs of sensor foils 100 laid in the X-direction are followed by a spacer layer 200 with a network structure, as is shown, for example, in 5 is shown. The spacer layer 200 can have large meshes, for example with mesh widths of 10*10 mm, for electrical insulation of the two sensor film levels. The lattice or mesh structure ensures a largely barrier-free vertical movement of leaking liquids.

A plurality of webs of sensor foils 100 are then laid in the Y direction on the upper spacer layer 200 . Each individual web is connected to the evaluation electronics 410 of the evaluation unit 400 at one end. A further non-electrically conductive layer 130, 150 can then be applied to the structure shown, it being necessary to ensure that leakage liquid can reach the sensor foils 100 in order to be able to provide a detection. In further versions, for example, the shower is installed above it or the roof is laid (e.g. with flat roofs).

In the structure shown, when leaking liquid occurs, a leak is first detected in a path in the Y direction due to a short circuit by the evaluation electronics 410 and then, due to the vertical flow of the leaking liquid, in a path in the X direction. The evaluation area of the leakage is determined by the existing web width of the sensor foils 100 and the X and Y signaling of the evaluation electronics 410 . The evaluation area can be changed as required by varying the width of the sensor film.

It is important that the leakage liquid can easily penetrate the sensor foils 100 and thus moves on to the next sensor foil level, which is achieved due to the sensor foils 100 and the layer structure described herein.

With the help of the matrix arrangement of the sensor films 100, it is possible to cover any large area, e.g. flat roofs, with sensor films 100 and still detect small leakage areas with the evaluation electronics 410. In this way, for example, major damage to buildings can be avoided.

A further possibility of locally delimiting the leakage detection consists in laying individual segments of a sensor film 100 which are not in contact with one another by means of adhesive tape or spacers. The size of the segments can be freely determined. For this purpose, for example, a sensor foil 100 can be divided into segments (e.g. by cutting to size). All segments must each be connected individually to the evaluation electronics 410 of an evaluation unit 400 via lines. A second layer of sensor foils 100, as in the matrix arrangement, can be omitted, but the wiring complexity is greater.

The contacting of the electrically conductive layers 130, 150 for the electrical connection to an evaluation unit 400 with the evaluation electronics 410 can have different requirements depending on the type of metal used for the layers 130, 150. Solder connections are generally not suitable when the insulating layer 110 is made of plastic because the soldering temperatures would melt the plastic. Furthermore, the different metals can only be soldered to different degrees. Furthermore, connecting the electrically conductive layers 130, 150 via a soldering process usually requires the execution of a skilled worker since this process is not user-friendly. The use of contact blocks 300 addresses this problem.

For example, the electrically conductive layers 130, 150 can be contacted via spring-loaded terminals. These are arranged in such a way that contact springs 330 press against each other on the sensor film 100 or the electrically conductive layers 130, 150, and thus make electrical contact with the two electrically conductive layers 130, 150 in each case.

9 shows different representations of components for the contacting of sensor foils 100 and 11 shows various representations of a contact unit 300 for contacting sensor foils 100.

The contact units 300 are designed, for example, in such a way that a housing 310 consists of an upper housing part 312 and a lower housing part 311 . The housing parts 311, 312 are made of plastic and have insulating properties. Both housing parts 311, 312 have each have a receptacle 314 into which the contacts 320 are inserted ( 9c ) and 11d ), e), f)).

11 a) shows the formation of contacts 320. The contacts 320 consist of a plastic housing and have on one side the two electrically conductive or guided embedded contact springs 330 made of copper, for example, which are provided for electrical contacting with the layers 130, 150. On the other side, the contacts 320 have two feet 324 which are inserted into corresponding receptacles 313 in the two housing parts 311 and 312. When inserting, snap-in hooks 326 also slide along a wall of receptacles 314 until these projections 317 are run over and held by projections 317 . The contacts 320 each have two contact springs 330 which, when the housing parts 311, 312 are in the connected state, press against the electrically conductive layers 130, 150 and thus provide the contacting.

The receptacles 314 are open on one side, as in FIGS 11e) and 11 f) shown so that wires 340 can be inserted into the corresponding openings 322 .

The upper housing part 312 has two latching arms 318 with latching hooks. The lower housing part 311 has corresponding rail-like guides 319 .

After the contacts 320 have been inserted into the respective receptacles 314 of the upper housing part 312 and the lower housing part 311 and the wires 340 of the lines 350 have been inserted into the openings 322, the two housing parts 311, 312 are connected to one another, the latching arms 318 of the upper housing part 312 are inserted into the guides 319 of the lower housing part 311. The latching hooks of the latching arms 318 can then have a first projection 360 in the guides 319, as in 11c ) shown, locked to each other and kept at a defined distance from each other. Therefore, there is a distance between the two housing parts 311, 312. The housing 310 with the housing parts 311, 312 can then be pushed onto a sensor film 100. The two housing parts 311, 312 are then pressed together until the latching hooks of the latching arms 318 engage the second lower projections 370, as shown in FIG 11c shown, engage behind and thus provide a lock. In this case, the contact springs 330 then press against the electrically conductive layers 130, 150 and provide contact via this. The pressure via the contact springs 330 is ensured due to the latching of the two housing parts 311, 312. For this purpose, the sensor film 100 may have to be partially freed from the protective layers 140, 160 in the area of the contact. This can be achieved by the measures mentioned above.

In order to prevent the housing parts 311, 312 from being pulled off a sensor film 100 or the electrically conductive layers 130, 150, the housing parts 311, 312 have holding means. In the in the 9 and 11 In the embodiments shown, the lower housing part 311 has cams 316 [ 9c ) and c )-f)], which engage in the latched state of the two housing parts 311, 312 in corresponding receptacles 315 on the upper housing part 312 and hold the sensor film 100 in between.

The wires 340 of the cable can be plugged in or screwed in for contact, similar to a luster terminal. The closed design of the housing 310 of the housing parts 311, 312, except for the cable connection at the rear, protects the contacts 320 from leaking liquid.

The described contacting via the contact units 300 is very user-friendly. Furthermore, no special contacting surface is necessary, on which e.g. other types of metal have to be applied.

Since the contacting of the sensor foil 100 can often no longer be accessed after it has been laid, e.g. in the case of an arrangement under a shower or on a flat roof, it can involve a great deal of effort in the event of a fault to access it. For example, in the case of a shower, the bathroom is tiled after laying sensor foils 100 and contacting, and the shower tray is glued with silicone. In the case of flat roofs, the sensor foil 100 is usually located under insulation and tar paper.

However, since the measurements by the evaluation unit 400 must make reliable statements, the evaluation electronics 410 are able to check the contacting of the contacts 320 with the electrically conductive layers 130, 150. This is done by contacting the two electrically conductive layers 130, 150 with at least two contacts 320 each. Each of these contacts 320 has a separate cable connection to the evaluation electronics 410. Before the evaluation electronics 410 start measuring the leakage liquid, the contacting of the electrically conductive layers 130, 150 is checked. For this purpose, a test current is sent from the evaluation electronics 410 via a first connecting cable to the first contact 320, further via the associated layer 130 or 150 to the second contact and from there via the second connecting cable back to the evaluation electronics 410 Posted. If this circuit is interrupted at any point, it will be registered by the 410 evaluation electronics. Otherwise it can be ensured that the subsequent measurement of leakage liquid is valid.

Metal contacts and the metal of the electrically conductive layers 130, 150 can also oxidize and thereby significantly increase the contact resistance, so that the evaluation electronics 410 are no longer able to carry out usable measurements. In order to prevent this, preferably permanently, the evaluation electronics 410 clean the contacts 320 with a cleaning current, similar to the minimum current for relay contacts.

In addition, there is the possibility in further versions of regenerating the contacts 320 with suitable electronics, for which purpose the cable of the contacts 320 of one of the electrically conductive layers 130, 150 is disconnected from the evaluation electronics 410 and connected to a cleaning unit with cleaning electronics. Existing oxide layers are then removed using suitable currents and voltages and the resulting plasma. The cleaned contacts 320 can then be reconnected.

The length of a connection cable can be several hundred meters and depends only on the resistance of the individual conductors. Since this resistance is very low in relation to the resistance measurement of the leaking liquid, large distances can be covered.

8th shows a flowchart of an evaluation unit 400 for operating a sensor device 500 and 10 shows a schematic representation of the structure of an evaluation unit 400 in one embodiment.

The evaluation unit 400 with the evaluation electronics 410 consists of an analog part and a digital part. The analog part is used to carry out a classic resistance measurement and is designed accordingly. Furthermore, the analog part has a contact interface 402 via which the lines 350 (cables) are connected from the contact units 300 to the evaluation unit 400 . The digital part has a controller 420, which has a microcontroller with appropriate software. The microcontroller is responsible for the evaluation and control. The control includes, for example, switching to contact testing and subsequent switching to testing of leaking liquid. Furthermore, this activity takes place after a fixed time interval. In the meantime, the microcontroller can switch the electronics to minimum energy consumption.

The evaluation unit 400 has an energy generation unit 430 (battery, rechargeable battery, mains operation) and an interface unit 440 which has an analog interface 442 , a serial interface 444 and a radio interface 446 . The interface unit 440 can be used, for example, to communicate or issue instructions with/to a programmable logic controller (PLC) 450, a host 460, a WLAN 470 network and/or a smartphone app. For example, warnings (display, siren, warning light, etc.) or messages (e-mail, SMS, app) can be issued. Instructions can also be issued, such as closing valves or notifying service staff. After a leak has been detected, a variety of measures can be taken, with the above examples not being conclusive.

A sensor device 500 can be controlled by the in 8th shown program sequence take place.

In step S0, the monitoring of a leak is started.

In step S1, the contacts 320 are checked, as above with reference to FIG 9 and 11 described.

In step S2 it is checked whether the contacts 320 are in order. If this is not the case, a message is issued in step S3. The contacts 320 can then be cleaned or contact units 300 can be exchanged. The method then starts again at step S1.

If no faults could be detected for the contacts 320, the measuring device is switched over in step S4 in order to avoid electrolysis effects on the contacts 320 and the electrically conductive layers 130, 150.

Then, in step S5, the leakage is measured via the sensor foils 100 in the manner described above by means of a resistance measurement.

If no leakage was detected in step S6, in step S8 a contact cleaning is carried out by means of current in the with respect to the 9 and 11 described way. However, if a leak is discovered, a message is issued in step S7, which can then trigger further measures.

After cleaning the contacts 320 in step S8, a deactivation takes place in step S9, The measurements are interrupted or paused for a definable period of time for an energy-saving mode.

In further embodiments that are not shown, a continuous measurement can also take place.

After step S9, the method begins again with step S1 until the process is ended.

A system with a sensor device 500 can be used, for example, indoors and outdoors (bathroom, kitchen, washroom, roof, etc.).

For this purpose, at least one sensor foil 100 can be laid and the sensor foil 100 can be connected to the evaluation electronics 410 . For this purpose, the output signals can be connected to a home automation controller.

In a further embodiment, at least one sensor foil 100 can be laid and the at least one sensor foil 100 can be connected via cables to evaluation electronics 410 arranged in the same room. In this case, it is possible for a display which shows the measurement results to be arranged in the same room. In this case, the sensor device 500 can be battery-operated, for example.

In yet another embodiment, the measurement results or instructions may be wirelessly transmitted to a host. From there, messages and status information containing the measurement results can be transmitted to a display or, for example, to various recipients via WLAN. For example, a message can be sent via e-mail or, for example, to a mobile phone via a corresponding app, etc.

In an industrial company, for example, at least one sensor film 100 can be laid in a room and connected to an evaluation unit 400 with corresponding evaluation electronics 410 via contact units and cables. The output signals can be connected to a PLC 450. For this purpose, the SPS 450 can be connected to a fieldbus (e.g. Profibus, Modbus, etc.). Status information and notifications can be sent and corresponding control instructions can be sent to other units (display, valves, etc.).

It should be understood that the foregoing detailed description and drawings, while representing certain exemplary embodiments of the invention, are intended for purposes of illustration only and should not be construed as limiting the scope of the invention. Various modifications of the configurations described are possible without departing from the scope of the following claims and their range of equivalence. In particular, features of the exemplary embodiments that are not mentioned in the claims also emerge from this description and the figures. Such features may also occur in combinations other than those specifically disclosed herein. Therefore, the fact that several such features are mentioned together in the same sentence or in some other type of textual context does not justify the conclusion that they can only occur in the specifically disclosed combination; instead, it is generally to be assumed that several such features can also be omitted or modified individually, provided this does not call into question the functionality of the invention.

Throughout the specification and claims, the term "a" is used as an indefinite article and does not limit the number of parts to one. Should "a" have the meaning of "only one", then this is to be understood by the person skilled in the art from the context or is clearly disclosed through the use of appropriate expressions such as "a single".

In this context, it should be noted that the terms "comprise", "have", "contain", "include" and "with" as used in this description and the claims and their grammatical changes are intended as a non-exhaustive list of features, such as process steps, devices, areas, sizes and the like and in no way exclude the presence of other or additional features or groupings of other or additional features.

Reference List

100

sensor foil

110

insulation layer

112

insulation layer

114

insulation layer

120

reinforcement layer

130

layer

140

protective layer

150

layer

160

protective layer

170

opening

200

spacer layer

300

contact unit

310

Housing

311

housing part

312

housing part

313

recording

314

recording

315

recording

316

cam

317

head Start

318

locking arm

319

guide

320

Contact

322

recording

324

Foot

326

latch hook

330

contact spring

340

wire

350

Management

360

head Start

370

head Start

400

evaluation unit

402

contact interface

410

evaluation electronics

420

steering

430

power supply unit

440

interface unit

442

analog interface

444

serial interface

446

radio interface

450

SPS

460

host

470

WIRELESS INTERNET ACCESS

480

smartphone app

500

sensor device

600

obstacles

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 2844972 B1 [0005, 0006]

Claims (16)

Sensor device for detecting the presence of a medium, comprising: at least one sensor film (100), wherein the sensor film (100) has at least a first electrically conductive layer (130) and a second electrically conductive layer (150), wherein between the first electrically conductive layer (130) and the second electrically conductive layer ( 150) at least one insulation layer (110) made of electrically non-conductive material is arranged, wherein - the sensor film (100) has openings (170) which run through the first electrically conductive layer (130), the second electrically conductive layer (150) and the at least one insulating layer (110), - Each of the openings (170) spans an equally large free area in relation to the first electrically conductive layer (130), the second electrically conductive layer (150) and the at least one insulating layer (110), and - The layer thickness of the at least one insulating layer (110) is greater than the layer thickness of the first electrically conductive layer (130) and the layer thickness of the second electrically conductive layer (150). sensor device claim 1 , wherein the openings (170) are stretched. sensor device claim 1 or 2 , A protective layer (140; 160) made of an electrically non-conductive material being arranged on the first electrically conductive layer (130) and/or the second electrically conductive layer (150). sensor device claim 3 , wherein the protective layer (140) on the first electrically conductive layer (130) and/or the protective layer (160) on the second electrically conductive layer (150) has openings (170) corresponding to the openings (170) in the first electrically conductive layer (130), the second electrically conductive layer (150) and the at least one insulating layer (110). Sensor device according to one of Claims 1 until 4 , wherein a first insulation layer (112) and a second insulation layer (114) are provided, at least one reinforcement layer (120) being arranged between the first insulation layer (112) and the second insulation layer (114) and the first insulation layer (112) having the first electrically conductive layer (130) and the second insulation layer (114) is connected to the second electrically conductive layer (150), the first insulation layer (112), the second insulation layer (114) and the reinforcement layer (120) having corresponding openings (170 ) to the openings (170) in the first electrically conductive layer (130) and the second electrically conductive layer (150). Sensor device according to one of Claims 1 until 5 , wherein at least one outer layer of the sensor film (100) has a hydrophobic and/or oleophobic coating. Sensor device according to one of Claims 1 until 6 , Having an evaluation unit (400) which is connected to the electrically conductive layers (130, 150) of the sensor film (100). Sensor device according to one of Claims 1 until 7 , having a contact unit (300), which has a housing (310) in which two opposing contacts (320) are accommodated, which are each connected to one of the two electrically conductive layers (130; 150), the contacts (320) can each be connected to at least one electrical line. sensor device claim 8 , wherein the housing (310) is formed in two parts and has a latching mechanism by means of which the contacts (320) can be pressed against the electrically conductive layers (130, 150) via the housing (310). Sensor device having a plurality of first webs of sensor foils (100) running parallel and spaced apart from one another and a plurality of second webs of sensor foils (100) running parallel and spaced apart from one another, the first webs and the second webs being arranged one above the other in mutually different orientations and each individual web is connected to a common evaluation unit (400). sensor device claim 10 , wherein the first webs of sensor foils (100) and the second webs of sensor foils (100) have at least one spacer layer (200), and/or at least the first webs of sensor foils (100) are separated from one another by at least one spacer layer (200). are separated. Procedure according to one of Claims 1 until 11 , wherein the layer thickness of the at least one insulation layer (110) is at least 6 times greater than the layer thickness of the at least one first electrically conductive layer (130) and the layer thickness of the at least one second electrically conductive layer (150). Method for detecting the presence of media using a sensor device (500) according to one of Claims 1 until 12 , With an evaluation unit (400) a Span voltage is applied to the two electrically conductive layers (130, 150), and wherein a change in voltage due to the presence of a medium in the area of an opening (170) is recognized by the evaluation unit (400) as the presence of the medium and a response to the presence is issued. procedure after Claim 13 , wherein the voltage is measured at the electrically conductive layers (130, 150) at definable intervals and the current direction is reversed after each measurement. Procedure according to one of Claims 12 until 15 , the method comprising checking the contacting of the contacts (320) with the electrically conductive layers (130, 150), a test current from the evaluation electronics (410) via a first connecting cable to the first contact (320) further via the layer assigned to it (130 or 150) is sent to the second contact (320) and from there via a second connecting cable back to the evaluation electronics (410). Procedure according to one of Claims 12 until 15 , the method comprising applying a cleaning current for contact cleaning.

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