Sensor for optical inspection of liquids

Abstract

The invention relates to a sensor for optical inspection of liquids, the sensor comprising a light source and a light detector, at least one first optical fibre extending from the light source into an inspection chamber, a second optical fibre being assigned to each of the at least one first optical fibre, the second optical fibre extending from the inspection chamber to the light detector, wherein the first and the assigned second optical fibers are opposite in the region of the inspection chamber. According to the invention, the sensor comprises a base body with a fastening section, the base body can be inserted into an assigned opening of a superordinate structural assembly, the base body can be fastened to the superordinate structural assembly at the fastening section, and the fastening section separates a first side and a second side of the base body from each other. Wherein the base body forms an inspection chamber on a first side, the light source and the light detector are arranged on a second side, and the at least one first optical fiber and the at least one second optical fiber are arranged in the interior of the base body, each penetrating through a fixed section.

Description

Technical Field

[0001] The invention relates to a sensor according to the preamble of claim 1 , a sensor arrangement having such a sensor and a method for producing such a sensor. Background Art

[0002] DE 102021201017 A1 discloses a measuring system for optically checking hydraulic fluids in pipelines. The pipeline has a transparent section through which light from a light source can be injected into the interior of the pipeline, wherein the light filtered by the liquid can be emitted from the pipeline again toward a light detector through other transparent sections. The transparent section is made relatively large, so that a high-quality inspection result can be achieved. However, the measuring device is therefore not suitable for use in pipelines that carry high hydraulic pressures, which can be 100 bar or more. The relatively large transparent section made of glass cannot withstand such pressure loads.

[0003] Another measuring system for optically checking liquids is known from WO 2014 / 090309 A1. Here, light is introduced and discharged into the liquid by means of optical fibers. The ends of the optical fibers are opposed to each other with a fiber spacing of perhaps 0.5 mm. The described system structure is more suitable for scientific research than for real hydraulic equipment. In particular, the small fiber spacing of 0.5 mm is achieved by a circular channel, the support of which is arranged inside a cup containing the liquid to be checked. The optical fiber is guided through the liquid unprotected here. In real hydraulic equipment, the optical fiber would be destroyed after a short time. The problem of pressure-resistant sealing of the optical fiber does not arise at all for cups used within the scope of test equipment. Summary of the invention

[0004] The advantage of the sensor according to the present invention is that it can be installed as a whole in the only opening of the upper structural assembly in order to check the liquid flowing in the upper structural assembly. The optical fiber is protected here to prevent damage caused by the high pressure of the liquid and / or by the high flow rate of the liquid. Here, it is impossible for liquid to reach the environment of the upper structural assembly from the side of the optical fiber from the inside of the upper structural assembly. The spacing between the first and second optical fibers in the inspection area can be further reduced relative to the prior art in order to improve the quality of the inspection result, even if a low-cost light source and a low-cost and thus mostly insensitive light detector are used. The sensor according to the present invention can be manufactured in large quantities at low cost and can be used in a large number of different upper structural assemblies without changes. It only slightly affects the flow in the upper structural assembly. The sensor requires particularly little structural space and is very strong.

[0005] According to claim 1, the sensor comprises a base body with a fastening section, wherein the base body can be inserted into an associated opening of a superordinate assembly, wherein the sensor can be fastened to the superordinate assembly at the fastening section, wherein the fastening section separates a first side and a second side of the base body from each other, wherein the base body forms an inspection chamber on the first side, wherein a light source and a light detector are arranged on the second side, wherein at least one first optical fiber and at least one second optical fiber are arranged inside the base body, wherein they each pass through the fastening section. Correspondingly, the first side is arranged inside the superordinate assembly, wherein the second side is arranged outside the superordinate assembly. The fastening section can be matched to a separate capping nut, which can be screwed to an external thread surrounding the opening in the superordinate assembly, so that the base body can be fastened to the superordinate assembly by means of the capping nut. The aforementioned opening in the superordinate assembly is preferably designed to be circular, wherein the fastening section of the base body is matched to the opening in such a way that the corresponding fixed connection can be closed in a liquid-tight manner.

[0006] The light source and / or the light detector are preferably fixed, preferably directly fixed on the second side of the matrix at most. The liquid mentioned is preferably oil, especially hydraulic oil, such as HLP or HEES. The liquid can be under high pressure during the inspection, and the high pressure can be greater than 100 bar, for example. The first and / or second optical fibers are preferably made of crystalline materials respectively, wherein they can also be made into hollow fibers (hollow silica waveguides (Hollow Silica Waveguide)) composed of glass. As a result, they conduct the preferred infrared light particularly well. Simple glass or SiO2 strongly absorbs the preferred infrared light and is therefore not preferred. The first and / or second optical fibers can also be composed of transparent plastic. The upper structural assembly is preferably a pipeline, a valve block, a pump, a hydraulic motor or a tank of a hydraulic circuit. The matrix is ​​preferably formed in one piece. In particular, if the first wall spacing should be adjustable, the matrix can be formed in multiple pieces.

[0007] At least one first optical fiber and at least one second optical fiber are preferably designed so that they can conduct infrared light with low loss. The inspection of the liquid is preferably carried out with infrared light, because extremely convincing measured values ​​can be achieved thereby. Preferably, light with a wavelength between 2650nm and 20000nm is used in order to obtain a particularly convincing structure. Correspondingly, the optical fiber should conduct this light particularly well. This can be achieved without problems by selecting suitable materials for the optical fiber. At least one first optical fiber and at least one second optical fiber are preferably arranged substantially completely inside the substrate, wherein they can extend into the light source or the light detector, wherein these optical fibers are preferably directly adjacent to the substrate.

[0008] Advantageous developments and refinements of the invention are described in the dependent claims.

[0009] It can be provided that at least one first optical fiber and at least one second optical fiber are each extended in a J-shaped bend such that the first optical fiber and the assigned second optical fiber are extended together in a U-shaped manner, wherein the respective U-shape comprises a base and two legs, wherein the inspection chamber is arranged in the region of the base, wherein the light source and the light detector are each arranged at the free ends of the assigned legs. This results in a particularly compact sensor. Nevertheless, too narrow a bending radius of the optical fiber can be avoided. The two legs preferably extend through the fixing section, wherein the legs preferably extend straight at most.

[0010] It can be provided that the inspection chamber is formed by an inspection slot which partially has a constant first wall spacing, wherein at least one first optical fiber and at least one second optical fiber exit in the region of the constant first wall spacing. The constant wall spacing can be easily established, wherein the wall spacing can nevertheless be selected to be particularly small. This results in a high evaluation quality.

[0011] It can be provided that the inspection gap has a first side wall with a first flat section and a second side wall with a second flat section, wherein the first and second sections extend parallel to each other at a first wall distance, wherein all first optical fibers exit at the first flat section, wherein all second optical fibers exit at the second flat section. Preferably, the first optical fibers terminate exactly flush at the first flat section, wherein the second optical fibers terminate exactly flush at the second section. It goes without saying that deviations from this ideal state may occur due to tolerances. For the quality of the inspection result, the fiber spacing at the end between the first and the assigned second optical fibers is primarily important. With this embodiment, on the one hand, a very narrow inspection chamber can be realized, which provides the best possible inspection result due to the low light attenuation. On the other hand, a sufficiently extended liquid film is generated in the inspection chamber, the optical properties of which correspond to the optical properties of the liquid flowing freely around the sensor, so that the evaluation result represents the entire liquid in the upper structural assembly. This embodiment is particularly cost-effective.

[0012] It can be provided that the second wall distance between the first and second side walls, measured next to the first and second flat sections, is greater than the first wall distance. As a result, tools, in particular saw blades or electro-erosion wires, for producing the first and second flat sections can be inserted into the base body without problems.

[0013] It can be provided that the inspection slot is open on the side of the basic body facing away from the fixing section. Through this opening, the tool mentioned can be inserted into the basic body without problems.

[0014] It can be provided that the first wall spacing is selected in such a way that the first and the assigned second optical fibers are opposite each other with a fiber spacing that is between 30 μm and 300 μm, preferably between 50 μm and 200 μm. The fiber spacing mentioned can be, for example, 100 μm. With such a narrow inspection chamber, it is possible that particles in the fluid flow past the inspection gap on the outside so that they do not interfere with the optical inspection of the fluid. It should be noted that particles with the diameter of the optical fibers may block all the light emitted by the first optical fiber so that it is essentially impossible for it to reach the assigned second optical fiber.

[0015] It can be provided that at least one first optical fiber and / or at least one second optical fiber are individually accommodated in respectively assigned fiber channels in the base body, wherein they are respectively bonded to at least a section of the fiber channels. Preferably, all first optical fibers and all second optical fibers are accommodated in respectively assigned fiber channels and are at least partially bonded there. In this way, the desired compressive strength and the desired tightness of the sensor are achieved.

[0016] It can be provided that at least one first optical fiber and / or at least one second optical fiber respectively have a constant first cross-sectional shape within the scope of their entire length, wherein the assigned fiber channel extends along the sealing length with a constant second cross-sectional shape, which is equidistantly matched to the first cross-sectional shape, so that a bonding gap is generated between the first and second cross-sectional shapes, wherein the bonding gap is filled with adhesive so that on the one hand the relevant first optical fiber or the relevant second optical fiber is fixedly connected to the substrate, wherein on the other hand liquid is prohibited from passing through the bonding gap from the interior of the upper structural assembly to the outside of the upper structural assembly. Preferably all first optical fibers and all second optical fibers have a constant cross-sectional shape within the scope of their entire length, wherein they are received in the corresponding adjusted fiber channel. It should be noted that the first or second optical fiber is not necessarily glued to the fiber channel in the center. Due to manufacturing tolerances, it is better to say that the opposite situation can be expected. However, as long as the adhesive exerts its sealing effect, this is no harm. When the sensor is used in a hydraulic system, the liquid in the upper structural assembly can be under a pressure of 100 bar or more. In the described manner, this high pressure can be reliably sealed. The adhesive is preferably an adhesive which has a low viscosity in the uncured state, in particular an acrylate adhesive or an epoxy adhesive.

[0017] The sealing length is preferably at least 50% of the diameter of the opening in the upper structural assembly. The bonding gap is preferably filled with adhesive within a range of at least 80% of the sealing length. Thus, a reliable seal can also be achieved with respect to the high pressure in the upper structural assembly.

[0018] It can be provided that the fiber channel opens out at the first or second side wall with a second cross-sectional shape. Correspondingly, the sealing length is measured starting from the first or second side wall. Preferably, the base body with the first and second optical fibers is produced in that a blank of the base body without a test gap is provided, wherein for each pair consisting of the first and the assigned second optical fiber, a single common optical fiber is glued into the relevant common fiber channel, wherein the test gap is then produced, wherein the common optical fiber is cut into the first optical fiber and the separate second optical fiber. Preferably, the test gap, in particular the first and second flat sections, are produced by sawing, wherein preferably a diamond saw blade is used at most. The test gap can be produced by means of electric spark cutting.

[0019] It can be provided that at least the following section of the base body is produced by a 3D printing method, at which the fiber channel extends in a curved manner. Thin and curved fiber channels can be produced economically in this way. Preferably, selective laser sintering (https: / / de.wikipedia.org / wiki / Selektives_Lasersintern) is used as a 3D printing method. Preferably, a part of the base body is produced in a conventional manner, especially in a cutting manner, wherein only the section with thin and curved fiber channels is produced by a 3D printing method in order to save costs.

[0020] Furthermore, a sensor device is claimed, wherein the sensor device comprises a superordinate assembly and a sensor according to the invention, wherein a filter is connected to the flow path in the flow direction of the liquid before the test gap, wherein the filter is designed in such a way that it filters out particles from the liquid that are larger than a first wall distance, thereby reliably preventing particles from adhering to the test gap.

[0021] A further sensor arrangement is claimed, wherein the sensor arrangement comprises a superordinate component and a sensor according to the invention, wherein the test slot is oriented parallel to the flow direction in the superordinate component, so that the flow of liquid in the superordinate component causes a flow through the test slot. This embodiment is not mandatory, since diffusion effects can already be sufficient to ensure sufficient oil exchange in the test slot. However, ideally the liquid is conveyed into the test slot by flow effects and by diffusion effects.

[0022] Furthermore, protection is claimed for a method for producing a sensor according to the invention, in which a blank without an inspection slot of a base body is provided, which blank has a common fiber channel for each pairing consisting of a first and a second optical fiber, in which the common optical fiber is glued into the common fiber channel, in which an inspection slot is subsequently produced, in which the common optical fiber is cut into a first optical fiber and a second optical fiber.

[0023] It goes without saying that the aforementioned features still to be explained below can be used not only in the respectively specified combination but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is explained in detail below with the aid of the accompanying drawings.

[0025] Figure 1 A sensor device having a sensor according to the invention is shown;

[0026] Figure 2 shows a perspective partial view of the base body in the region of the 3D-printed second section;

[0027] Figure 3 Shown in accordance with Figure 1 A roughly schematic partial longitudinal section view of a sensor in the region of the inspection gap; and

[0028] Figure 4 A roughly schematic partial cross section of the sensor is shown in the region of the fiber channel. DETAILED DESCRIPTION

[0029] Figure 1 A sensor device 10 is shown with a sensor 20 according to the invention. The sensor 20 is installed in a superordinate structural component 11 in the form of a hydraulic line. The superordinate structural component 11 has a circular opening 12, which is surrounded by a circular annular projection, which in turn is provided with an external thread 13. A lock nut 35 is screwed onto the external thread 13, which clamps a fastening section 33 in a fluid-tight manner on a base body 30 of the sensor 20. The fastening section 33 is designed here as a radially outwardly projecting fastening web 34, which is designed rotationally symmetrically with respect to a center axis 36 of the base body 30. The aforementioned center axis 36 coincides with the center of the circle of the opening 12.

[0030] The fixing section 33 separates the first side and the second side 31, 32 of the base body 30 from each other. The first side 31 is arranged in the cavity 15 filled with liquid inside the upper structural assembly 11. The second side 32 is arranged outside the upper structural assembly 11. A light source 23 and a light detector 24 are fixed on the second side 32. The light source 23 is, for example, a light emitting diode that emits infrared light. The light detector 24 includes, for example, a photodiode, wherein at most a plurality of photodiodes are preferably provided, which are sensitive in different spectral ranges by means of optical filters. The light detector 24 can also be made in the type of a spectrometer, so that the spectrum can be continuously decomposed. The light source 23 and the light detector 24 are connected to an evaluation unit 26, which controls the light source 23 and determines at least one property of the liquid from the measurement results generated by the light detector 24. Preferably, the aging state of the hydraulic oil is determined, wherein in particular the following characteristic values ​​are determined, which indicate how long the hydraulic oil can be expected to be used.

[0031] The state of the liquid in the upper structural assembly 11 is preferably continuously monitored with the evaluation device 26. In particular, the liquid used and its quality can be determined. The aging state of the liquid and / or its expected possible service life can be found out. Contamination caused by water or other fluids, for example, can be identified. If a situation such as exceeding the reliable liquid service life or being lower than the reliable liquid quality is found, the upper structural assembly 11 can be blocked in terms of its function or relieved in terms of its load. The evaluation device 26 is preferably in a data exchange connection with a cloud server via the Internet, wherein a computationally intensive evaluation is performed on the cloud server, wherein the user can, for example, call the results of the cloud server with the aid of a small program. The evaluation device 26 can be connected to a local display, on which the found inspection results are displayed in real time. Other sensors, such as temperature sensors, for inspecting the liquid can be arranged in the housing 66.

[0032] The light emitted by the light source 23 is guided to the inspection slot 40 by means of the first optical fiber 21. In the inspection slot 40 there is a liquid to be inspected, which is illuminated by the light emerging from the first optical fiber 21. Depending on the state of the liquid, different parts of the spectrum are absorbed, wherein the light filtered in this way is at least partially incident on the second optical fiber 22, wherein the light is guided by the second optical fiber to the light detector 24. The first and second optical fibers 21, 22 are preferably each made as glass fibers. The light source 23, the light detector 24 and the evaluation unit 26 are preferably surrounded by a housing 66, which is fixedly connected to the base body 30, so that the components mentioned are preferably protected against environmental influences according to protection class IP68 at most.

[0033] When the last-mentioned light is incident on the second optical fiber 22, a lot of light can be lost, wherein the loss depends decisively on the fiber spacing (in Figure 2 The distance between the end faces of the first and second optical fibers 21, 22 is 51 in the figure, that is, how large the distance is between the end faces of the first and second optical fibers 21, 22. If the fiber distance is in the order of magnitude of the diameter of the first and second optical fibers 21, 22, the light losses are so small that they rarely interfere with the signal evaluation. The sensor according to the invention has the advantage that the first wall distance of the test slot 40 can be selected to be arbitrarily small within the scope of manufacturability (in Figure 3 45 ), wherein the flow within the upstream assembly 11 is nevertheless only slightly disturbed.

[0034] At this point, it should be noted that there may be very high pressures inside the upper component 11. Conventional light-transmissive materials, such as glass, are generally not able to withstand such high pressures. However, within the scope of the invention, the high liquid pressure acts only on the very small end faces of the first and second optical fibers 21, 22, which are firmly bonded to the base body 30. This arrangement can withstand high liquid pressures in the upper component without problems. This is particularly the case because in Figure 1 The sealing length 52 in the figure can be selected to be large. Ideally, the first or second optical fiber 21, 22 is connected to the assigned fiber channel (in the range of its entire circumference) along the entire sealing length 52. Figure 4 The bonding surface, which is larger than the end face of the first or second optical fiber 21, 22, can transmit the force generated by the liquid pressure without any problem. It goes without saying that the ideal bonding described above can only be achieved approximately, wherein the bonding that can actually be achieved is absolutely good enough.

[0035] The first and second optical fibers 21, 22 have a U-shaped course, which has a base and two legs. The inspection slot 40 is arranged in the area of ​​the base. The two legs each pass through the fixing section 33, wherein the light source 23 and the light detector 24 are each arranged at one end of the assigned leg. Correspondingly, the first and second optical fibers 21, 22 each extend in a J-shaped bend when viewed in themselves.

[0036] This J-shape of the fiber channel 50 makes its manufacture significantly difficult. First of all, it should be noted that the diameter of the fiber channel 50 is between Figure 1 Shown exaggeratedly.

[0037] The base body 30 preferably has a first section 60 manufactured in a conventional manner, in particular by cutting, and a second section 61 printed by 3D. First, the first section 60 is manufactured, wherein the second section 61 is subsequently printed, so that the first and second sections 60, 61 are connected to each other in a material-locking manner. In the region of the first section 60, the straight legs of the U-shape are arranged. These sections of the fiber channel 50 can be manufactured without problems by means of drilling. The drilling diameter is selected so large that the liquid adhesive can be injected there without problems. The adhesive gap can be excessively thick there, because the strength of the adhesive there is not important.

[0038] In the 3D-printed second section 61, the fiber channel 50 is first reduced to a diameter that is optimal for bonding by means of a funnel-shaped taper 55. Adjacent to the funnel-shaped taper 55 is a curved section of the fiber channel 50, which has a diameter of 1.5 mm in diameter over its total length. Figure 4 The second cross-sectional shape shown in FIG. This section of the fiber channel 50 cannot be manufactured using conventional manufacturing methods, so 3D printing methods, especially selective laser sintering, have been selected. In order to keep the corresponding manufacturing time short, the volume of the second section 61 is reduced to a minimum.

[0039] Figure 2 A perspective partial view of the substrate 30 in the region of the second section 61 of 3D printing is shown. The flat surface 62 on the substrate 30 is preferably manufactured in a conventional manner, wherein it serves as a starting point for 3D printing. There, two tubular sections 64 are first printed, which follow the desired course of the first or second optical fiber respectively assigned. The tubular sections 64 each have a circular outer circumferential shape, wherein the assigned first or second optical fiber is arranged in the corresponding center of the circle. The outer diameter of the outer circumferential shape mentioned is preferably constant next to the first and second side walls 41, 42. The two tubular sections 64 are preferably configured to be mirror-symmetrical to each other.

[0040] The two tubular sections 64 are reinforced by means of the webs 63 so that in the flat section (at the Figure 3 In the region of the tubular section 64 (reference numerals 43, 44), substantially no deformations are produced under the action of flow forces which would have a negative impact on the evaluation results. The web 63 is designed in the form of a flat plate with a constant thickness, the center surface of which coincides with the plane containing the first and second optical fibers. The aforementioned thickness of the web 63 is selected to be significantly smaller than the outer diameter of the tubular section 64 in the sense of minimizing the volume.

[0041] The recess 65 in the web 63 is indicated, which is arranged in the extension of the flat section (reference numerals 43, 44) of the first or second side wall 41, 42. The flat section mentioned is preferably produced in a separate working step after 3D printing, for example by sawing or spark cutting. In this case, the recess 65 serves as an exit area for a corresponding tool, that is, a saw blade or a cutting wire. Furthermore, the web 65 extends from the flat surface 62 up to the two tubular sections 64.

[0042] Figure 3 Shown in accordance with Figure 1 4 , in the region of the inspection slot 40. The inspection slot 40 is defined by a first and a second side wall 41, 42. The first and second optical fibers 21, 22 each exit at a flat first or second section 43, 44 of the assigned first or second side wall 41, 42, where they terminate flush with the section. This can be achieved by gluing a single common optical fiber into the base body 30, wherein the common fiber is cut into the first and the separate second optical fibers 21, 22 only during the production of the first and second flat sections 43, 44. In addition, in this way, the best possible orientation of the first and second optical fibers 21, 22 in the region of the inspection slot 40 is ensured, so that light losses due to misorientation are avoided when the light is transferred from the first optical fiber 21 to the second optical fiber 22.

[0043] The first and second flat sections 43, 44 extend parallel to each other with a first wall spacing 45. The first wall spacing 45 is selected to be so small that the desired evaluation can be performed as well as possible, wherein the first wall spacing can still be manufactured. Next to the first and second flat sections 43, 44, the first and second side walls 41, 42 have a significantly larger second wall spacing 46. The profile in the region of the second wall spacing 46 is manufactured with a 3D printing method. It is optimized on the one hand in terms of the flow direction of low eddy currents, so that it extends in a gently circular arc shape. In the region of the flat sections 43, 44, the profile is made so as to provide free space, which allows the tool for manufacturing the flat sections 43, 44 to be placed without problems. The edge diameter of the circular flat sections 43, 44 is just selected to be as large as necessary for the inspection of the liquid. Therefore, the corresponding separate manufacture of the first and second flat sections 43, 44 can be carried out in the shortest possible time.

[0044] In addition, Figure 3 In FIG. 5 , it can be seen that the bonding gap 56 between the first or second optical fiber 21, 22 and the respectively assigned fiber channel 50 is filled with adhesive 57. Figure 3In the region shown, the adhesive layer is loaded particularly high due to the pressure of the liquid. The adhesive layer thickness is optimized particularly there with regard to the best adhesive strength. It goes without saying that the adhesive layer thickness and the diameter of the first and second optical fibers 21, 22 are in the Figure 3 Shown exaggeratedly.

[0045] Figure 4 A schematic partial cross section of the sensor 20 in the region of the fiber channel 50 is shown. The cross section is at the sealing length (at Figure 1 52) in the region perpendicular to the first or second optical fiber 21, 22. The first and second optical fibers 21, 22 have a first circular cross-sectional shape 53 at their outer circumference within the scope of their total length. The second cross-sectional shape 54 of the fiber channel 50 is equidistantly matched to the first cross-sectional shape 53, so that it is also circular here. The diameter difference of half between the first and second cross-sectional shapes 53, 54 corresponds to the nominal thickness of the bonding gap 56. It goes without saying that the bonding of the first or second optical fiber 21, 22 in the assigned fiber channel 50, right in the middle, is difficult to achieve. This is not important within the scope of the present invention, as long as only sufficient tightness and strength of the bonding are achieved.

[0046] List of reference numerals:

[0047] 10 Sensor device

[0048] 11 Superior structural components

[0049] 12 Opening

[0050] 13 External thread

[0051] 14 Flow direction

[0052] 15 Cavity filled with liquid

[0053] 20 Sensors

[0054] 21 First Optical Fiber

[0055] 22 Second optical fiber

[0056] 23 Light Source

[0057] 24 Photodetectors

[0058] 25 Examination Room

[0059] 26 evaluation units

[0060] 30 Matrix

[0061] 31 First side

[0062] 32 Second side

[0063] 33 Fixed segments

[0064] 34 Fixed tab

[0065] 35 Lock nut

[0066] 40 Check the gap

[0067] 41 First side wall

[0068] 42 Second side wall

[0069] 43 First flat section

[0070] 44 Second flat section

[0071] 45 First wall distance

[0072] 46 Second wall spacing

[0073] 47 Maximum horizontal dimension

[0074] 50 Fiber Channel

[0075] 51 Fiber spacing

[0076] 52 Sealing length

[0077] 53 First cross-sectional shape

[0078] 54 Second cross-sectional shape

[0079] 55 Funnel-shaped taper

[0080] 56 Glue gap

[0081] 57 Adhesive

[0082] 60 The first section of the base

[0083] 61 The second section of the base

[0084] 62 Flat surface

[0085] 63 splice

[0086] 64 Tubular segments

[0087] 65 Gap

[0088] 66 Shell

Claims

1. A sensor (20) for optically inspecting a liquid flowing in a superordinate structural assembly (11), wherein the sensor (20) comprises a light source (23) and a light detector (24), wherein an inspection chamber (25) of the sensor (20) is arranged inside the superordinate structural assembly (11), wherein at least one first optical fiber (21) extends from the light source (23) to the inspection chamber (25), wherein a second optical fiber (22) is respectively assigned to each of the at least one first optical fiber (21), the second optical fiber extending from the inspection chamber (25) to the light detector (24), wherein the first and the assigned second optical fibers (21, 22) are arranged opposite each other in the region of the inspection chamber (25), so that light emitted by the light source (23) can reach the light detector (24) via the first optical fibers (21), further via the liquid in the inspection chamber (25), and further via the second optical fibers (22), It is characterized in that The sensor (20) comprises a base body (30) with a fixing section (33), wherein the base body (30) can be inserted into an assigned opening (12) of a superordinate structural assembly (11), wherein the base body can be fixed to the superordinate structural assembly (11) at the fixing section (33), wherein the fixing section (33) separates a first side and a second side (31, 32) of the base body (30) from each other, wherein the base body (30) forms an inspection chamber (25) on the first side (31), wherein the light source (23) and the light detector (24) are arranged on the second side (32), wherein at least one first optical fiber (21) and at least one second optical fiber (22) are arranged inside the base body (30), wherein they each pass through the fixing section (33).

2. The sensor (20) according to claim 1, At least one first optical fiber (21) and at least one second optical fiber (22) are respectively extended in a J-shaped bend, so that the first optical fiber (21) and the assigned second optical fiber (22) are extended together in a U-shape, wherein the corresponding U-shape includes a base and two legs, wherein the inspection chamber (25) is arranged in the area of ​​the base, and wherein the light source (23) and the light detector (24) are respectively arranged at the free ends of the assigned legs.

3. The sensor (20) according to any one of the preceding claims, The inspection chamber (25) is formed by an inspection slot (40) which partially has a constant first wall distance (45), wherein at least one first optical fiber (21) and at least one second optical fiber (22) exit in the region of the constant first wall distance (45).

4. The sensor (20) according to claim 3, The inspection slot (40) has a first side wall (41) with a first flat section (43) and a second side wall (42) with a second flat section (44), wherein the first and second sections (43, 44) extend parallel to each other at a first wall distance (45), wherein all first optical fibers (21) emerge at the first flat section (43), and wherein all second optical fibers (22) emerge at the second flat section (44).

5. The sensor (20) according to claim 4, A second wall distance (46) between the first and second side walls (41, 42), measured next to the first and second flat sections (43, 44), is greater than the first wall distance (45).

6. The sensor (20) according to any one of claims 3 to 5, The inspection slot (40) is open on the side of the base body (30) facing away from the fastening section (33).

7. The sensor (20) according to any one of the preceding claims, The first wall distance (45) is selected such that the first and the associated second optical fibers (21, 22) are disposed opposite each other at a fiber distance (51) between 30 μm and 300 μm, preferably between 50 μm and 200 μm.

8. The sensor (20) according to any one of the preceding claims, At least one first optical fiber (21) and / or at least one second optical fiber (22) are individually accommodated in respectively assigned fiber channels (50) in the base body (30), wherein they are respectively bonded to at least a section of the fiber channel (50).

9. The sensor (20) according to claim 8, At least one first optical fiber (21) and / or at least one second optical fiber (22) each have a constant first cross-sectional shape (53) over their entire length, wherein the assigned fiber channel (50) extends along the sealing length (52) with a constant second cross-sectional shape (54), which second cross-sectional shape is equidistantly matched to the first cross-sectional shape (53), so that a bonding gap (56) is generated between the first and second cross-sectional shapes, wherein the bonding gap (56) is filled with an adhesive (57), so that on the one hand the relevant first optical fiber or the relevant second optical fiber (21, 22) is fixedly connected to the base body (30), and on the other hand liquid is prevented from passing through the bonding gap (56) from the interior of the upper structural assembly (11) to the outside of the upper structural assembly (11).

10. The sensor (20) according to claim 9, The fiber channel (50) opens out at the first or second side wall (41, 42) with a second cross-sectional shape (54).

11. The sensor (20) according to any one of claims 8 to 10, In this case, at least that portion of the base body (30) at which the fiber channel (50) runs in a curved manner is produced by a 3D printing method.

12. A sensor device (10) comprising a superordinate structural assembly (11) and a sensor (20) according to any one of the preceding claims, A filter is connected to the flow path upstream of the inspection gap (40) in the flow direction (14) of the liquid, wherein the filter is designed such that it filters out particles from the liquid that are greater than a first wall distance (45).

13. A sensor device (10) comprising a superordinate structural assembly (11) and a sensor (20) according to any one of claims 3 to 11, wherein the sensor device is designed as claimed in claim 12, The inspection slot (40) is oriented parallel to the flow direction (14) in the superordinate component (11), so that a flow of liquid in the superordinate component (11) causes a flow through the inspection slot (40).

14. A method for producing a sensor (20) according to any one of claims 8 to 11, provided that these claims refer back to claim 3, A blank of the base body (30) without an inspection slot (40) is provided, which has a common fiber channel for each pair consisting of a first and a second optical fiber (21, 22), wherein the common optical fiber is glued into the common fiber channel, wherein the inspection slot is subsequently produced, wherein the common optical fiber is cut into the first and second optical fibers (21, 22).

Images