Liquid level monitoring system

Abstract

The invention discloses a liquid level monitoring system which comprises a light source capable of generating an input light beam; the interferometer is optically connected to the light source, the interferometer is configured to divide an input light beam into two output light beams which are respectively emitted to a solution to be detected and the reference reflecting part, and return light beams reflected by the solution to be detected and the reference reflecting part are converged in the interferometer and are interfered to form an interference spectrum; the interference spectrum carries the liquid level information of the to-be-detected solution, so that the purpose of monitoring the liquid level of the to-be-detected solution is achieved. In addition, the interferometer can also enable the output light beam to be focused outside the interferometer, the focus of the output light beam can extend into the solution to be detected on the premise that the output light beam does not need to be in contact with the solution to be detected, and non-contact in-situ lossless high-precision monitoring on the solution to be detected is achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of liquid level monitoring, and in particular, relates to a liquid level monitoring system. Background Art

[0002] In chemical experiments and industrial production, it is necessary to monitor the status of the reaction liquid at all times, such as liquid surface stratification, liquid surface film formation, liquid surface flow, liquid surface evaporation, etc. High-precision liquid level monitoring can not only reveal the status of the chemical reaction, but also accurately detect and supervise the chemical production process.

[0003] There are various types of liquid level meters, the main types are tuning fork vibration type, magnetic levitation type, pressure type, ultrasonic wave, sonar wave, magnetic flap, radar, etc. However, the accuracy of these liquid level meters is low and it is difficult to meet the needs of liquid level monitoring in chemical experiments and industrial production. Summary of the invention

[0004] The embodiment of the present application provides a liquid level monitoring system, which can perform in-situ non-destructive high-precision monitoring of a solution to be tested.

[0005] The embodiment of the present application provides a liquid level monitoring system, which includes: a light source, configured to generate an input light beam; and an interferometer, optically connected to the light source, the interferometer is configured to split the input light beam into two output light beams to be emitted to a solution to be tested and a reference reflector respectively, and to make the return light beams reflected by the solution to be tested and the reference reflector merge in the interferometer and interfere to form an interference spectrum, and the interference spectrum carries the liquid level information of the solution to be tested. The interferometer is also configured to make each output light beam emit from the interferometer and focus on the outside of the interferometer.

[0006] Optionally, the interferometer includes a beam splitter and two optical paths, the interferometer is optically connected to the light source through the beam splitter; the beam splitter is optically connected to each optical path and is configured to split an input light beam into two output light beams, and output them to the two optical paths respectively; each optical path is configured to converge the focus of the received output light beam to the outside of the end of the optical path, and provide a return light beam to the beam splitter so that the return light beams of the two optical paths interfere in the beam splitter to form an interference spectrum.

[0007] Optionally, the optical path includes a plurality of light polymerizing components, and the plurality of light polymerizing components are distributed along a propagation direction of the output light beam. The optical path sequentially focuses the received output light beam multiple times through the plurality of light polymerizing components to extend the length of the optical path.

[0008] Optionally, the plurality of light polymerizers include a first light polymerizer and at least one second light polymerizer, and in the propagation direction of the output light beam, the first light polymerizer is located on the upstream side of the at least one second light polymerizer; the first light polymerizer is configured to converge the output light beam at a first focus, and the at least one second light polymerizer is configured to converge the light beam diverging after the first focus at at least one second focus, and the second focus at the end in the propagation direction of the output light beam is located outside the optical path and is spaced apart from the end of the optical path.

[0009] Optionally, the second light polymerizer includes a first lens and a second lens arranged opposite to each other, the first lens is configured to converge the divergent output light beam into a parallel light beam, and the second lens is configured to converge the parallel light beam output by the first lens at a second focus; in the propagation direction of the output light beam, the image distance of the second lens of the second light polymerizer at the end is greater than the distance between the second lens and the end of the optical path.

[0010] Optionally, the optical pathway also includes a tube body, a hollow portion is formed inside the tube body, and the hollow portion axially penetrates the tube body; a plurality of light polymers are arranged in the hollow portion at intervals along the axial direction of the tube body, and the focus of the light polymer at the end in the propagation direction of the output light beam is located outside the axial direction of the tube body and is spaced apart from the tube body.

[0011] Optionally, the optical pathway is configured such that a distance between a focus of the output light beam outside the optical pathway and an end of the optical pathway is adjustably settable.

[0012] Optionally, the optical pathway includes at least one second light polymerizer, the second light polymerizer includes a first lens and a second lens arranged opposite to each other, the first lens is configured to converge a divergent output light beam into a parallel light beam, and the second lens is configured to converge the parallel light beam output by the first lens to a second focus; the second lens is configured to be movably arranged along the propagation direction of the output light beam to adjust the position of the second focus.

[0013] Optionally, the light source is a broadband light source; and / or the wavelength range of the light source is 790nm to 910nm; and / or the central wavelength of each optical element of the interferometer matches the central wavelength of the light source, and the bandwidth of each optical element is greater than or equal to the bandwidth of the light source.

[0014] Optionally, the liquid level monitoring system also includes: a spectrometer, optically connected to the interferometer and configured to collect interference spectra; a data processing device, connected to the spectrometer and configured to perform optical tomography on the solution to be tested based on the liquid level information carried by the interference spectrum collected by the spectrometer.

[0015] The liquid level monitoring system provided by the embodiment of the present application includes a light source and an interferometer. The interferometer can divide the input light beam generated by the light source into two output light beams, and respectively project them to the solution to be tested and the reference reflector. The return light beam formed after reflection by the solution to be tested and the return light beam formed after reflection by the reference reflector return to the interferometer, and converge in the interferometer to interfere to form an interference spectrum, which carries the liquid level information of the solution to be tested, thereby achieving the purpose of liquid level monitoring of the solution to be tested. The embodiment of the present application can flexibly adjust the spatial resolution by selecting the bandwidth of the light source, thereby improving the monitoring accuracy. In addition, the interferometer can focus the output light beam on the outside of the interferometer. Under the premise that the interferometer does not need to contact the solution to be tested, the focus of the output light beam can extend into the inside of the solution to be tested, and the light spot gathers at the focus, and the imaging resolution is the highest, realizing non-contact, in-situ, non-destructive, high-precision monitoring of the solution to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 It is a structural schematic diagram of a liquid level monitoring system according to an embodiment of the present application.

[0018] Figure 2 yes Figure 1 A schematic cross-sectional structure diagram of the optical pathway of the liquid level monitoring system is shown.

[0019] Figure 3 This is an image of the n-hexane solution before volatilization monitored by the liquid level monitoring system 1 provided in the embodiment of the present application.

[0020] Figure 4 This is an image of the n-hexane solution after volatilization monitored by the liquid level monitoring system 1 provided by the embodiment of the present application. DETAILED DESCRIPTION

[0021] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating examples of the present application. In the accompanying drawings and the following description, at least some of the known structures and technologies are not shown to avoid unnecessary ambiguity in the present application; and, for clarity, the size of some structures may be exaggerated. In addition, the features, structures or characteristics described below may be combined in one or more embodiments in any suitable manner.

[0022] In the description of the present application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating directions or positional relationships, are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0023] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the embodiments of the present application. In the description of the present application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0024] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The embodiments will be described in detail below in conjunction with the accompanying drawings.

[0025] Figure 1 Schematic diagram of the structure of a liquid level monitoring system according to an embodiment of the present application. Figure 1 Also shown is a solution to be tested 2 and a reference reflector 3. Figure 1The liquid level monitoring system 1 provided in the embodiment of the present application includes a light source 10 and an interferometer 20. The light source 10 is configured to generate an input light beam. The interferometer 20 is optically connected to the light source 10, and the interferometer 20 is configured to split the input light beam output by the light source 10 into two output light beams to be emitted to the solution to be tested 2 and the reference reflector 3 respectively, and to make the return light beam reflected by the solution to be tested 2 and the reference reflector 3 merge and interfere in the interferometer 20 to form an interference spectrum, and the interference spectrum carries the liquid level information of the solution to be tested 2. The interferometer 20 is also configured to make each output light beam emit from the interferometer 20 and focus on the outside of the interferometer 20.

[0026] The light source 10 may be a broadband light source. The wider the spectrum generated by the light source 10 is, the higher the longitudinal resolution is.

[0027] Exemplarily, the interferometer 20 may be a Michelson interferometer.

[0028] The interferometer 20 may be directly optically connected to the light source 10 , or may be indirectly optically connected to the light source 10 via an optical element, such as a circulator.

[0029] The two output beams formed by the interferometer 20 splitting the input beam into coherent beams.

[0030] The two output beams of the interferometer 20 are respectively used to irradiate the solution to be tested 2 and the reference reflector 3. The return beam reflected by the solution to be tested 2 and the return beam reflected by the reference reflector 3 meet the interference condition and converge in the interferometer 20 to interfere and form an interference spectrum. In other words, the interferometer 20 includes two optical paths, one of which is directed to the solution to be tested 2 and then returns, and the other is directed to the reference reflector 3 and then returns. In order to ensure that the two return beams can interfere, it is necessary to ensure that the optical path difference of the two optical paths is consistent, so that an interference spectrum can be formed. Optionally, the optical elements contained in the two optical paths are strictly consistent to minimize the dispersion of the system in hardware.

[0031] The reference reflector 3 may be a reflector, so that most of the light beams irradiated to the reference reflector 3 can be reflected back to the interferometer, thereby improving the return efficiency.

[0032] After the output light beam is directed to the solution to be tested 2, different substances at different depths in the solution to be tested 2 can be irradiated. Different substances have different refractive indices to light and different backscattering intensities to light, so the imaging brightness is also different. For example, the imaging of some substances is very bright, because strong backscattered light is generated; while the imaging of some substances is very dark, such as the imaging of aqueous solutions, where only the interface between water and air has a strong line of imaging, and the interior is relatively dim, because the refractive index at the junction of the liquid surface has a sudden change, generating stronger backscattered light. Therefore, the return light beam reflected by the solution to be tested 2 and the reference reflector 3 converges in the interferometer 20 and interferes to form an interference spectrum that carries the liquid level information of the solution to be tested 2. The liquid level monitoring system 1 provided in the embodiment of the present application is very suitable for observing the liquid surface boundary, thereby measuring the liquid surface thickness.

[0033] The light intensities of the two output beams divided by the interferometer 20 are different. Among them, the output beam with a weaker light intensity is directed to the reference reflector 3, and the output beam with a stronger light intensity is directed to the solution to be tested 2. This is because the backscattered light reflected by the solution to be tested 2 is very weak, and the stronger light splitting for the solution to be tested 2 can increase the light intensity of the return light beam reflected by the solution to be tested 2. Exemplarily, the light intensity ratio of the two output beams divided by the interferometer 20 can be 1:9.

[0034] The liquid level monitoring system 1 provided in the embodiment of the present application includes a light source 10 and an interferometer 20. The interferometer 20 can split the input light beam generated by the light source 10 into two output light beams, and respectively emit them to the solution to be tested 2 and the reference reflector 3. The return light beam formed after reflection by the solution to be tested 2 and the return light beam formed after reflection by the reference reflector 3 return to the interferometer 20, and converge in the interferometer 20 to interfere to form an interference spectrum. The interference spectrum carries the liquid level information of the solution to be tested 2, thereby achieving the purpose of liquid level monitoring of the solution to be tested 2.

[0035] The embodiment of the present application can flexibly adjust the spatial resolution by selecting the bandwidth of the light source 10, thereby improving the monitoring accuracy. In addition, the interferometer 20 can focus the output light beam on the outside of the interferometer 20. Under the premise that the interferometer 20 does not need to contact the solution 2 to be tested, the focus of the output light beam can be extended into the inside of the solution 2 to be tested, and the light spot is concentrated at the focus, and the imaging resolution is the highest, realizing non-contact, in-situ, non-destructive, high-precision monitoring of the solution 2 to be tested. In addition, the focus of the output light beam is directed to the inside of the solution 2 to be tested, which can also improve the light return efficiency of the optical path.

[0036] In some embodiments, the interferometer 20 includes a beam splitter 21 and two optical paths 22, and the interferometer 20 is optically connected to the light source 10 through the beam splitter 21. The beam splitter 21 is optically connected to each optical path 22, and is configured to split the input light beam output by the light source 10 into two output light beams, and output them to the two optical paths respectively. Each optical path 22 is configured to converge the focus of the received output light beam to the outside of the end of the optical path 22, and provide the return light beam to the beam splitter 21 so that the return light beams of the two optical paths 22 interfere in the beam splitter 21 to form an interference spectrum.

[0037] Optionally, the interferometer 20 may include a first optical path and a second optical path, and the reference reflector 3 coupled to the first optical path may be a reflector. The first optical path is optically connected to the reflector to transmit the output light beam received by the first optical path to the reflector, and provide the return light beam reflected by the reflector to the beam splitter 21. The second optical path can be optically connected to the solution to be measured 2 to focus the output light beam received by the second optical path on the solution to be measured 2, and provide the return light beam reflected by the solution to be measured 2 to the beam splitter 21.

[0038] The beam splitter 21 may be directly optically connected to the light source 10 , or may be indirectly optically connected to the light source 10 via an optical element.

[0039] The beam splitter 21 may be directly connected to each optical path 22, or may be indirectly connected to each optical path 22 through an optical element. Exemplarily, at least one collimator is disposed between the beam splitter 21 and each optical path 22, so that the output light beam is collimated by the collimator and then emitted to the optical path 22.

[0040] The optical splitter 21 is used to split and distribute the input light beam and combine the return light beams of each optical path 22. The optical splitter 21 can be, for example, a coupler. As another example, the optical splitter 21 can also be any other suitable device capable of splitting, combining and distributing optical signals.

[0041] The optical splitter 21 may include an input port 211 and two output ports 212, wherein the input port 211 is optically connected to the light source 10 to receive an input light beam output by the light source 10. The two optical paths 22 are optically connected to a corresponding output port 212. It should be noted that the output port 212 not only enables light (such as the aforementioned output light beam) to be output from the inside of the optical splitter 21, but also enables light (such as the aforementioned return light beam) to enter the inside of the optical splitter 21 through the output port 212.

[0042] The optical path 22 is used to transmit the output light beam and the return light beam, and a single or multiple identical or different optical elements may be provided in the optical path 22. The end of the optical path 22 refers to the end at the end in the propagation direction of the output light beam. In other words, the output light beam is emitted from the optical path 22 through the end of the optical path 22.

[0043] It can be understood that the two optical paths 22 are optically isolated from each other to avoid mutual interference and influence.

[0044] It is understandable that most of the solutions to be tested are placed in reaction containers, and the liquid surface is a certain distance from the container mouth. The inventors recognize that in order to ensure a higher lateral resolution, the focal position of the optical path 22 is relatively short. For a higher reaction container, it is difficult for the focal point to be projected into the solution to be tested in the reaction container.

[0045] To this end, in some embodiments, reference Figure 2 The cross-sectional structure diagram of the optical path of the liquid level monitoring system 1 is shown in FIG. Figure 2 The dashed line in the figure schematically represents the output beam. Figure 2 The optical path 22 includes a plurality of light polymerizing components, and the plurality of light polymerizing components are distributed along the propagation direction of the output light beam. The optical path 22 focuses the received output light beam multiple times in sequence through the plurality of light polymerizing components to extend the length of the optical path 22.

[0046] A plurality of light-emitting polymers are sequentially distributed along the propagation direction of the output light beam, and each light-emitting polymer can converge or focus the output light beam. After being focused, the output light beam can diverge again until it encounters the next light-emitting polymer and is focused again. The focal point at the end in the propagation direction of the output light beam is outside the end of the optical path 22.

[0047] Exemplarily, the light-aggregating member may be a lens, which is a high-performance, wide-spectrum scanning lens to ensure that a large-range scan is performed while preventing distortion of images at locations far from the optical axis.

[0048] As some other examples, the light converging element may also be any other suitable optical element capable of converging light.

[0049] The embodiment of the present application arranges multiple optical polymer components in the optical path 22 to focus the output light beam multiple times in sequence, thereby appropriately extending the propagation path of the output light beam, thereby extending the length of the optical path 22, making it easier for the optical path 22 to extend into a container with a long barrel mouth distance to directly monitor the solution to be tested in the container. While ensuring a better spatial resolution, the loss of light directed to the solution to be tested is reduced, the return efficiency of the optical path and the system signal-to-noise ratio are improved, and the monitoring accuracy and monitoring effect are improved.

[0050] In some embodiments, the plurality of light polymerizers include a first light polymerizer 221 and at least one second light polymerizer 222. In the propagation direction of the output light beam, the first light polymerizer 221 is located at the upstream side of the at least one second light polymerizer 222. The first light polymerizer 221 is configured to converge the output light beam to a first focus X, and the at least one second light polymerizer 222 is configured to converge the light beam diverging after passing through the first focus X to at least one second focus Y. The second focus Y at the end in the propagation direction of the output light beam is located outside the optical path 22 and is spaced apart from the end of the optical path 22.

[0051] The first light polymerizer 221 is located at the upstream side of the at least one second light polymerizer 222 . The output light beam in the optical path 22 first passes through the first light polymerizer 221 and then passes through the at least one second light polymerizer 222 .

[0052] The collimator between the beam splitter 21 and each optical path 22 outputs a parallel light beam, and the first light polymerizer 221 can focus the parallel light beam at a first focus X, which is located inside the optical path 22. The divergent light beams after passing through the first focus X are irradiated to the second light polymerizer 222, and the second light polymerizer 222 can focus the divergent light beams at a second focus Y again.

[0053] Each second light polymerizer 222 corresponds to a second focus Y. Optionally, the number of the second light polymerizer 222 may be one, and the second focus Y formed by the second light polymerizer 222 converging the light is located outside the optical path 22 and is spaced apart from the end of the optical path 22. Optionally, the number of the second light polymerizer 222 may also be multiple, and the second light polymerizer 222 adjacent to the first light polymerizer 221 can focus the light beam diverging after passing through the first focus X to the second focus Y, and the other second light polymerizers 222 can focus the light beam diverging after passing through the second focus Y adjacent to it to another second focus Y. Among them, only the second focus Y at the end in the propagation direction of the output light beam is located outside the optical path 22 and is spaced apart from the end of the optical path 22, and the other second focuses Y are all inside the optical path 22.

[0054] Optionally, the first light polymerizing element 221 may be a scanning lens.

[0055] The embodiment of the present application uses two light polymer components to extend the length of the optical path 22 , which is low-cost and can reduce light loss to a minimum.

[0056] In some embodiments, the second light condenser 222 includes a first lens 2221 and a second lens 2222 that are arranged opposite to each other, the first lens 2221 is configured to converge the divergent output light beam into a parallel light beam, and the second lens 2222 is configured to converge the parallel light beam output by the first lens 2221 to a second focus Y. In the propagation direction of the output light beam, the image distance of the second lens 2222 of the second light condenser 222 at the end is greater than the distance between the second lens 2222 and the end of the optical path 22.

[0057] The first lens 2221 and the second lens 2222 are arranged opposite to each other along a propagation direction of the output light beam, so that the output light beam is transmitted in parallel through the first lens 2221 and the second lens 2222 .

[0058] The second light emitting diode 222 at the end in the propagation direction of the output light beam is the last second light emitting diode 222 and is also the second light emitting diode 222 adjacent to the end of the optical path 22 .

[0059] The embodiment of the present application designs the position of the second lens 2222 of the second light polymerizer 222 at the end so that the image distance of the second lens 2222 is greater than the distance between the second lens 2222 and the end of the optical path 22, thereby ensuring that the second focus Y formed by the output light beam converged by the second lens 2222 is located outside the end of the optical path 22, with a simple structure and ingenious design.

[0060] In some embodiments, the optical path 22 further includes a tube body 223, the interior of the tube body 223 forms a hollow portion 2231, and the hollow portion 2231 axially penetrates the tube body 223. A plurality of light-emitting polymers are arranged in the hollow portion 2231 at intervals along the axial direction of the tube body 223, and the focus of the light-emitting polymer at the end in the propagation direction of the output light beam is located outside the axial direction of the tube body 223 and is arranged at intervals from the end of the tube body 223.

[0061] The light polymerizing element may be connected to the inner tube wall of the tube body 223 in a suitable manner. For example, the inner tube wall of the tube body 223 may be provided with a circumferentially extending annular groove, and the light polymerizing element is embedded in the annular groove.

[0062] Optionally, the tube body 223 may include a plurality of tube segments, which are fixedly connected or detachably connected in sequence along the axial direction of the tube body 223. The light polymerizing member may be located at the axial end of the corresponding tube segment to facilitate the connection operation between the light polymerizing member and the tube body 223. As another example, the tube body 223 may be an integrally formed structure.

[0063] The interior of the tube body 223 forms a hollow portion 2231, which allows the light beam to propagate axially in the hollow portion 2231. The tube body 223 may be made of a light shielding material.

[0064] The inner wall of the tube body 223 may be coated with a reflective material to reduce light scattering when the output light beam is emitted toward the inner wall of the tube body 223 .

[0065] It can be understood that the end of the tube body 223 refers to the end at the end in the propagation direction of the output light beam in the tube body 223, that is, the end for the output light beam to be emitted.

[0066] Optionally, the plurality of light-emitting elements may include a first light-emitting element 221 and at least one second light-emitting element 222. The first light-emitting element 221 is capable of converging the output light beam to a first focus X in the tube body 223, and the at least one second light-emitting element 222 is configured to converge the light beam diverging after passing through the first focus X to at least one second focus Y, and the second focus Y at the end in the propagation direction of the output light beam is located outside the tube body 223 and spaced from the end of the tube body 223.

[0067] The first light-receiving unit 221 may be adjacent to the beginning of the tube 223 , and the second light-receiving unit 222 at the endmost in the propagation direction of the output light beam may be adjacent to the end of the tube 223 .

[0068] A transparent cover 224 may be provided at the end of the tube 223, and at least one second light polymerizing member 222 is provided between the first light polymerizing member 221 and the transparent cover 224. The transparent cover 224 blocks the hollow portion 2231, so that the output light beam passes through the transparent cover 224 and is focused on the outside of the end of the tube 223. The transparent cover 224 may protect the light polymerizing members, and prevent impurities such as water and dust from entering the hollow portion 2231 and contaminating the light polymerizing members. Exemplarily, the transparent cover 224 may be a sapphire sheet or other structural members with high structural strength and good light transmittance.

[0069] The embodiment of the present application can provide a relatively closed light path for the optical path 22 by providing the tube body 223, effectively preventing the light beam in the optical path 22 from being disturbed or affected by external light. In addition, the tube body 223 can carry multiple light polymerizing components and other optical elements included in the optical path 22, with a high degree of structural integration, and the structure of the optical path 22 is more stable.

[0070] In some embodiments, the optical pathway 22 is configured such that the distance between the focus of the output light beam outside the optical pathway 22 and the end of the optical pathway 22 can be adjusted. In other words, the distance between the focus of the output light beam outside the optical pathway 22 and the end of the optical pathway 22 can be adjusted through the optical pathway 22.

[0071] By adjusting the focal position of the output light beam focused on the outside of the optical pathway 22 through the optical pathway 22, the focal point can be placed exactly at a preset position in the solution 2 to be tested, so as to accurately monitor various subtle state changes of the solution 2 to be tested, such as liquid surface stratification, liquid surface film formation, liquid surface flow, and subtle changes in liquid surface height, thereby improving the monitoring accuracy.

[0072] The optical path 22 of the embodiment of the present application can adjust the specific position of the focus of the output light beam formed outside the optical path 22. By adjusting the focus position, the liquid level monitoring system 1 can be suitable for liquid level monitoring of test solutions of various liquid level heights, and liquid level monitoring of test solutions contained in various containers of different heights, thereby improving the application versatility and flexibility of the liquid level monitoring system 1.

[0073] In some embodiments, the optical pathway 22 may include a plurality of light polymers, at least some of which may be movably disposed along the propagation direction of the output light beam, so that the distance between the focus of the output light beam outside the optical pathway 22 and the end of the optical pathway 22 may be adjusted by moving at least some of the light polymers, and the adjustment method is simple and reliable.

[0074] In some embodiments, the optical path 22 may include at least one second light condenser 222, the second light condenser 222 includes a first lens 2221 and a second lens 2222 that are arranged opposite to each other, the first lens 2221 is configured to converge the divergent output light beam into a parallel light beam, and the second lens 2222 is configured to converge the parallel light beam output by the first lens 2221 to a second focus Y. The second lens 2222 is configured to be movably arranged along the propagation direction of the output light beam to adjust the position of the second focus Y.

[0075] The output light beam input into the optical path 22 may be emitted to the second light-aggregating component 222 directly, or may be emitted to the second light-aggregating component 222 after passing through other optical elements (such as a collimator, other light-aggregating components, etc.).

[0076] Optionally, the number of the second light polymerizer 222 can be one, and the second lens 2222 of the second light polymerizer 222 is located at the end of the optical path 22, and the second focus Y formed after passing through the second lens 2222 is located outside the optical path 22. The second lens 2222 can move along the propagation direction of the output light beam, so as to adjust the distance between the second focus Y formed after passing through the second lens 2222 and the end of the optical path 22. It can be understood that the movement of the second lens 2222 can also adjust the distance between the first lens 2221 and the second lens 2222. Since the light beam between the first lens 2221 and the second lens 2222 is a parallel light beam, the distance adjustment between the two has little effect on the light path transmission efficiency.

[0077] Optionally, the number of the second light-emitting polymerizers 222 may be more than two. The second lens 2222 of at least one second light-emitting polymerizer 222 is configured to be movably disposed along the propagation direction of the output light beam. Exemplarily, the at least one second light-emitting polymerizer 222 may be a second light-emitting polymerizer 222 at the end in the propagation direction of the output light beam.

[0078] In some embodiments, the optical pathway 22 further includes a tube body 223 . The light-collecting member of the optical pathway 22 is disposed in a hollow portion 2231 in the tube body 223 and is movably connected to the tube body 223 along a propagation direction of the output light beam.

[0079] Optionally, the optical path 22 may include at least one second light-emitting element 222 disposed in the tube body 223, the second light-emitting element 222 including a first lens 2221 and a second lens 2222 disposed opposite to each other, the second lens 2222 being configured to be movably connected to the tube body 223 along the propagation direction of the output light beam. Exemplarily, the second lens 2222 may be embedded in a sleeve, the sleeve being movably disposed along the axial direction of the tube body 223 to drive the second lens 2222 to move axially relative to the tube body 223.

[0080] The inventors recognize that spectral bandwidth is an important parameter of the light source. The wider the light source bandwidth, the shorter the coherence length and the higher the longitudinal resolution. For this reason, in some embodiments, the light source 10 is a broadband light source. The liquid level monitoring system 1 can use a broadband light source to perform high-precision micron-level monitoring of the liquid level state of the solution to be tested that is several millimeters (e.g., one or two millimeters) high, and the longitudinal resolution and monitoring accuracy of the system can reach 2-5 microns.

[0081] At the same time, the imaging depth of the liquid level monitoring system 1 must also be considered. To this end, in some embodiments, the wavelength range of the light source 10 is 790nm to 910nm.

[0082] The smaller the central wavelength of the light source 10, the higher the resolution; the larger the central wavelength, the greater the imaging degree. Thus, a balance can be achieved between resolution and imaging depth. The light source 10 of the embodiment of the present application is a broadband light source, and its band range is between 790nm and 910nm. The central wavelength of the output light beam emitted by the light source 10 is 850nm, and the bandwidth is 120nm. It can obtain both a higher resolution and a sufficient imaging depth to meet the purpose of liquid level monitoring of a variety of solutions to be tested.

[0083] In some embodiments, the central wavelength of each optical element of the interferometer 20 matches the central wavelength of the light source 10, and the bandwidth of each optical element is greater than or equal to the bandwidth of the light source, so as to ensure that the bandwidth of the light source is not lost and ensure a high longitudinal resolution of the entire system.

[0084] Optionally, the optical elements of the interferometer 20 may include, for example, a beam splitter, a collimator, and light emitting elements.

[0085] In some embodiments, the liquid level monitoring system 1 further includes a spectrometer 30 and a data processing device 40. The spectrometer 30 is optically connected to the interferometer 20 and is configured to collect interference spectra. The data processing device 40 is connected to the spectrometer 30 and is configured to perform optical tomography on the solution 2 to be tested according to the liquid level information carried by the interference spectra collected by the spectrometer 30.

[0086] The spectrometer 30 may include an input port, an achromatic collimating lens, a grating, a focusing lens, a detector, etc. The input port of the spectrometer 30 may be an optical fiber input, and the divergent light of the optical fiber is converted into a parallel light beam through the achromatic collimating lens and hits the grating, and the divergent light of the grating is finally focused on the pixel of the linear array detector through the focusing lens.

[0087] The data processing device 40 may be a computer. The data processing device 40 controls the optical subsystem to collect interference spectrum signals through the mechanical structure and the electric control subsystem, and transmits the signals to the software subsystem. The data can be analyzed in real time through algorithm processing and the three-dimensional model of optical tomography can be displayed.

[0088] Specifically, when the focus generated by the interferometer 20 reaches the inside of the solution to be tested 2, the light is incident on the interface between the two substances in the solution to be tested 2, generating strong backscattered light. The original spectrum is Fourier transformed, and the frequency domain spectrum obtained by the spectrometer is converted into the spatial domain. After spectral calibration, the distance between the two surfaces of the liquid can be obtained.

[0089] The liquid level monitoring system 1 provided in the embodiment of the present application not only achieves a micron-level spatial resolution that is unmatched by existing liquid level meters, but is also capable of performing two-dimensional imaging of the liquid level state of the solution to be tested and three-dimensional imaging of the crystals inside the solution to be tested, thereby facilitating real-time detection of subtle changes in the liquid level state.

[0090] In some embodiments, the liquid level monitoring system 1 also includes a circulator 50, the circulator 50 includes a first port 51, a second port 52 and a third port 53, the first port 51 is optically connected to the light source 10, the second port 52 is optically connected to the interferometer 20, and the third port 53 is optically connected to the spectrometer 30.

[0091] The input light beam generated by the light source 10 is incident on the circulator 50 through the first port 51 and is emitted to the interferometer 20 through the second port 52 of the circulator 50. The interference spectrum generated by the interferometer 20 is incident on the circulator 50 through the second port 52 and is output to the spectrometer 30 through the third port 53.

[0092] In the embodiment of the present application, the circulator 50 is provided to make the optical path between the light source 10, the interferometer 20 and the spectrometer 30 clearer and reduce the interference of the optical path.

[0093] The liquid level monitoring system 1 provided in the embodiment of the present application can monitor the liquid level change of the solution to be tested minutely and accurately. The liquid level monitoring situation of the liquid level monitoring system 1 in the embodiment of the present application is described below by taking the solution to be tested as a normal hexane solution as an example.

[0094] Figure 3 is an image of a n-hexane solution before volatilization monitored by the liquid level monitoring system 1 provided in an embodiment of the present application, Figure 4 This is an image of the n-hexane solution after volatilization monitored by the liquid level monitoring system 1 provided by the embodiment of the present application. Figure 3 and Figure 4 The thickness change of the solution before and after the volatilization of n-hexane within the preset time is shown. The initial height of the n-hexane solution contained in the regular cylindrical container is 1440μm. After a period of time, the height of the n-hexane solution in the regular cylindrical container is 550μm, which is 62% volatilized. In this way, the volatilization of n-hexane in the n-hexane solution within the preset time is obtained.

[0095] It can be seen that the liquid level monitoring system 1 provided in the embodiment of the present application is capable of capturing slight changes in the liquid level (up to micrometer level) when the liquid level of the solution to be tested is slightly disturbed or changed.

[0096] The liquid level monitoring system 1 provided in the embodiment of the present application also has the ability to monitor the stratification, impurities and other structures inside the solution to be tested. The liquid level monitoring system 1 can not only obtain a two-dimensional image of the stratification, impurities and other structures inside the solution to be tested, but also obtain three-dimensional information inside the solution to be tested through a three-dimensional scanning function.

[0097] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, m and / or n can represent: m exists alone, m and n exist at the same time, and n exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0098] In the description of the embodiments of the present application, the term "plurality" refers to more than two (including two).

[0099] In the embodiments of the present application, "parallel" includes not only the absolutely parallel situation, but also the roughly parallel situation conventionally recognized in engineering; at the same time, "perpendicular" also includes not only the absolutely perpendicular situation, but also the roughly perpendicular situation conventionally recognized in engineering. For example, if the angle between two directions is 85°-90°, the two directions can be considered perpendicular; if the angle between two directions is 0°-5°, the two directions can be considered parallel.

[0100] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A liquid level monitoring system, characterized in that: include: a light source configured to generate an input light beam; as well as An interferometer, optically connected to the light source, configured to split the input light beam into two output light beams to be emitted to the solution to be tested and the reference reflector respectively, and to make the return light beams reflected by the solution to be tested and the reference reflector merge and interfere in the interferometer to form an interference spectrum, wherein the interference spectrum carries the liquid level information of the solution to be tested; The interferometer is further configured such that each of the output light beams exits the interferometer and is focused outside the interferometer.

2. The liquid level monitoring system according to claim 1, characterized in that: The interferometer comprises a beam splitter and two optical paths, the interferometer is optically connected to the light source through the beam splitter; the beam splitter is optically connected to each of the optical paths and is configured to split the input light beam into two output light beams and output them to the two optical paths respectively; Each of the optical paths is configured to converge the focus of the received output light beam outside the end of the optical path and provide the return light beam to the beam splitter so that the return light beams of the two optical paths interfere in the beam splitter to form the interference spectrum.

3. The liquid level monitoring system according to claim 2, characterized in that: The optical path includes a plurality of light-emitting polymer components, and the plurality of light-emitting polymer components are distributed along the propagation direction of the output light beam. The optical path sequentially focuses the received output light beam multiple times through the plurality of light-emitting polymer components to extend the length of the optical path.

4. The liquid level monitoring system according to claim 3, characterized in that: The plurality of light polymerizing elements include a first light polymerizing element and at least one second light polymerizing element, and in the propagation direction of the output light beam, the first light polymerizing element is located at an upstream side of the at least one second light polymerizing element; The first light polymerizing member is configured to converge the output light beam at a first focus, and the at least one second light polymerizing member is configured to converge the light beam diverging after passing through the first focus at at least one second focus, and the second focus at the end in the propagation direction of the output light beam is located outside the optical path and is spaced apart from the end of the optical path.

5. The liquid level monitoring system according to claim 4, characterized in that: The second light-aggregating member comprises a first lens and a second lens disposed opposite to each other, wherein the first lens is configured to converge the divergent output light beam into a parallel light beam, and the second lens is configured to converge the parallel light beam output by the first lens to the second focus; In the propagation direction of the output light beam, the image distance of the second lens of the second light ray polymerizing member located at the end is greater than the distance between the second lens and the end of the optical path.

6. The liquid level monitoring system according to claim 3, characterized in that: The optical path further comprises a tube body, a hollow portion is formed inside the tube body, and the hollow portion axially penetrates the tube body; The plurality of light polymerizing members are spaced apart in the hollow portion along the axial direction of the tube body, and the focus of the light polymerizing member at the end in the propagation direction of the output light beam is located outside the axial direction of the tube body and spaced apart from the tube body.

7. The liquid level monitoring system according to claim 2, characterized in that: The optical pathway is configured such that a distance between the focal point at which the output light beam is outside the optical pathway and an end of the optical pathway is adjustably settable.

8. The liquid level monitoring system according to claim 7, characterized in that: The optical path includes at least one second light-aggregating member, the second light-aggregating member includes a first lens and a second lens disposed opposite to each other, the first lens is configured to converge the divergent output light beam into a parallel light beam, and the second lens is configured to converge the parallel light beam output by the first lens to a second focus; The second lens is configured to be movably disposed along a propagation direction of the output light beam to adjust a position of the second focus.

9. The liquid level monitoring system according to claim 1, characterized in that: The light source is a broadband light source; and / or The wavelength range of the light source is 790nm to 910nm; and / or The central wavelength of each optical element of the interferometer matches the central wavelength of the light source, and the bandwidth of each optical element is greater than or equal to the bandwidth of the light source.

10. The liquid level monitoring system according to claim 1, characterized in that: Also includes: a spectrometer optically connected to the interferometer and configured to collect the interference spectrum; A data processing device is connected to the spectrometer and is configured to perform optical tomography on the solution to be tested according to the liquid level information carried by the interference spectrum collected by the spectrometer.

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