75 results about "Refractometer" patented technology

The invention discloses an online refractometer calibration method, which comprises a standard condition calibration mode and a working condition calibration mode, and calibration items comprise temperature indication error, refractive index or concentration indication error, repeatability and stability. The standard condition calibration mode is used for calibration under the conditions of specific refractive index or concentration and specified temperature, and is suitable for a detachable instrument or the condition that the requirement for measurement accuracy is high and the instrument can be used as a reference instrument; the working condition calibration mode is used for calibration under the working medium and working condition, and is suitable for instruments which cannot be detached or the condition that working condition parameters of the instruments need to be calibrated. A standard condition calibration mode can adopt a fixed online refractometer calibration device, and dynamic calibration under a specified temperature condition is realized through a constant-temperature liquid storage tank and a circulating pipeline in the device; the working condition calibration mode can adopt a mobile online refractometer calibration device which is connected with a working condition pipeline provided with a calibrated online refractometer to dynamically calibrate the calibrated online refractometer on a user site under the working condition.

This work relates to a geometric-phase metasurface combined with a fluidic circuit for tuning the properties of the metasurface (especially its diffraction efficiency). We consider two aspects of particular interest: A) Dynamic on-demand diffractive optics (operating in transmission), both as optical elements for altering incident light, and as sensors of the refractive index of a fluid; and B) Transparent, reflective displays. Here the display itself is transmissive, but operates in reflection. One application of dynamic on-demand diffractive optics is to replace the lens array often needed in light field displays.

The utility model relates to a laser cleaning device for a refractometer. The laser cleaning device comprises a refractometer prism, an optical fiber and a laser, the refractometer prism is embedded in the end face of the online refractometer and comprises a first plane and a second plane; the first plane is exposed out of the outer surface of the end face of the online refractometer and is in contact with to-be-detected liquid; the second plane is opposite to the first plane and is positioned in the online refractometer; the optical fiber is arranged in the online refractometer and comprises a first end face and a second end face; the first end face is opposite to a second plane of the refractometer prism, and the second end face is connected with the laser; the laser is used for generating a laser beam capable of cleaning dirt attached to the first plane. The cleaning degree of cleaning can be greatly improved, noise and vibration are avoided, no mechanical operation part exists, energy is saved, cleaning can be conducted while measurement is conducted, and the measurement precision is not affected.

The nitrogen blowing instrument refractor is characterized by comprising a fuming cupboard, a nitrogen blowing instrument body is arranged on the fuming cupboard, an illuminating lamp is arranged beside the nitrogen blowing instrument body, a placement plate is arranged on the fuming cupboard, a sliding groove is formed in the placement plate, a supporting plate is arranged in the sliding groove, a transverse moving groove is formed in the supporting plate, and a guide rod is arranged in the transverse moving groove; a sliding block is arranged in the transverse moving groove; when observation is needed, a supporting plate is pulled out of a placement plate along a sliding groove, then a sliding block is moved left and right, the sliding block is made to move left and right in a transverse moving groove along a guide rod, through front-back and left-right movement, a turning mirror on a connecting block is made to move to the position over a 96-well plate, observation is conducted from the upper end of the turning mirror, the 96-well plate is illuminated by an illuminating lamp, and the 96-well plate is illuminated by the illuminating lamp. Light is transmitted to the eyes of an observer at the upper end of the turning mirror through the two refraction lenses, observation is completed, the head does not need to go deep into a fuming cupboard for observation, harm to the body is reduced, meanwhile, observation can be conducted without closing nitrogen blowing, and the usability is improved.

The light transmission structure comprises a light transmission piece and a plurality of light source sets, the wavelengths of light emitted by the light source sets are different, the light transmission piece is provided with a plurality of independent light inlet channels, each light inlet channel is provided with a light inlet and a light outlet, the light inlets correspond to the light source sets in a one-to-one mode, and the light source sets are arranged on the light inlet channels in a one-to-one mode. The light outlets correspond to the light inlet side of a prism of the refractometer, and the light inlet channels are arranged at intervals and are crossed with one another, so that divergence angles of light beams emitted by the light outlets are adjusted, the light beams are ensured not to be overlapped after being imaged, namely a bright-dark interface is relatively clear during imaging, the measurement accuracy of the refractive index of liquid is ensured, and the measurement accuracy of the refractive index of the liquid is improved. And the calculation deviation of the liquid concentration is ensured to be within a reasonable range.

The utility model discloses a fixed online refractometer calibration device which comprises a plurality of liquid storage bottles, a constant-temperature liquid storage tank, a refractometer calibration structure and a circulating pipeline, the liquid storage bottles are used for containing different liquid media. The constant-temperature liquid storage tank is respectively connected with the plurality of liquid storage bottles; two ends of the circulating pipeline are respectively communicated with the constant-temperature liquid storage tank; the refractometer calibration structure is arranged on the circulating pipeline and comprises a reference refractometer, a calibrated refractometer and a temperature sensor. According to the fixed online refractometer calibration device, dynamic calibration can be implemented under the conditions of specific refractive index or concentration and specified temperature, and data deviation caused by factors such as temperature and flow of a liquid medium in offline static calibration is avoided; the device is suitable for detachable online refractometers or online refractometers which have high requirements on measurement accuracy and can be used as reference instruments, and is reasonable in design and high in operability.

The utility model relates to the technical field of pipeline connection, in particular to a pipe joint convenient for mounting a refractometer, which comprises a joint body, and a joint inner groove is arranged on the upper end face of the joint body to ensure that a sensor can be stably mounted in the joint so as to perform accurate measurement or monitoring work. The left side and the right side of the connector body are arranged to be planar installation end faces, two guide cavities are formed in the bottom of the connector inner groove in a bilateral symmetry mode, and an installation opening is formed in the middle of the bottom face of the connector inner groove and used for installing and fixing the refractometer. When the connector is used, the planar mounting end face is arranged at the side end of the connector body, and the pipe connecting groove is formed in the connector position of the pipe connector, so that the connector body is in butt joint with a pipeline to form a sealed folding opening, the butt joint sealing performance of the pipeline and the connector body is greatly improved, and the fluid leakage condition is prevented.

Methods and systems configured to measure content of a target substance in a fluid sample using a refractometer including a light source and a light sensor. A method includes: calibrating the refractometer by identifying a calibration pixel pattern of first pixels of the light sensor illuminated by light from the light source that has reflected off a sensing surface of a container including a reference fluid having a known reference density; identifying a blood pixel pattern of second pixels of the light sensor illuminated by light from the light source that has reflected off the sensing surface when the fluid sample is present in the container; identifying a pixel shift distance along the light sensor from the calibration pixel pattern to the fluid pixel pattern; and determining the content of the target substance in the fluid sample based on the pixel shift distance.

The invention belongs to the technical field of bletilla striata polysaccharide preparation, and provides a high-purity bletilla striata polysaccharide preparation quality control method, which comprises: constructing a raw material spectrum-polysaccharide content prediction model by using Fourier transform near infrared spectroscopy and partial least squares regression PLSR, and intelligently determining an initial material-liquid ratio based on a predicted value; in the extraction stage, the concentration is monitored in real time through an online refractometer, the ultrasonic power, the extraction time or the volume of a supplemented solvent is dynamically adjusted, and it is ensured that the concentration and the viscosity of an extracting solution are in the optimal interval; in the purification stage, the dosage of a purification reagent and the heating rate are dynamically adjusted according to the real-time concentration; in the concentration stage, according to the real-time concentration and viscosity, the vacuum degree is adjusted in a segmented mode, heating is controlled, and end point coking is prevented; according to the invention, on-line monitoring and closed-loop feedback control of key parameters in the whole process are realized, and the purity, uniformity and production stability of the product are remarkably improved.

The invention relates to the technical field of physical quantity precision measurement, in particular to a piston effective area measurement system and method. The system comprises an optical pressure measuring device and a piston pressure gauge pressure measuring device. The optical pressure measuring device comprises a box body, a measuring cavity, a reference cavity and a laser refractometer. The measuring cavity is used for filling a gas medium; the reference cavity maintains a vacuum state; the laser refractometer emits laser to the measuring cavity and the reference cavity. The piston pressure gauge pressure measuring device comprises a piston pressure gauge which comprises an air cylinder and a piston. The piston divides the cylinder into a first space and a second space. The gas source is communicated with the second space and the measuring cavity through the three-way valve, the refractive index of gas in the measuring cavity is obtained through the laser refractometer, and the pressure of the gas is determined through the refractive index of the gas. Calibration of the effective area of the piston is traced to basic physical constants and high-precision measured physical quantities, the pressure is accurately measured, and high precision and reliability of a calibration result are guaranteed.

1. The name of this design product: Handheld refractometer. 2. Purpose of this design product: This design product is used to measure the total content of soluble substances in liquids. 3. The key point of the design of this product lies in its shape. 4. The picture or photo that best illustrates the design points: three-dimensional picture.

The invention discloses a method for detecting the salinity of water in oil, which comprises the following steps: step a, uniformly mixing an oil sample, measuring a sample, adding a non-polar solvent into the sample, and uniformly mixing to obtain a sample mixed solution; step b, carrying out centrifugal treatment on the sample mixed solution, standing, carrying out oil-water separation on the sample mixed solution, obtaining a mixed solution of a non-polar solvent and oil liquid on the upper layer of the sample mixed solution, and obtaining a water phase on the lower layer of the sample mixed solution; c, according to the volume of the water phase separated from the sample mixed solution, carrying out water volume adaptation treatment to obtain a detection water sample; and step d, sucking the detection water sample, dripping the detection water sample on a refraction prism of the seawater salinity detector, obtaining the salinity concentration in the detection water sample, and determining whether the water sample is seawater or fresh water according to the salinity concentration of the water sample.

The utility model discloses a refractometer cleaning waste liquid collecting device which comprises a collecting box arranged on one side of a refractometer, the collecting box comprises a waste liquid cavity, a clean cavity and a top cover from bottom to top, a partition plate is arranged between the waste liquid cavity and the clean cavity, and the partition plate is at least used for separating the waste liquid cavity from the clean cavity; a plurality of vertical plates with different heights are arranged on the inner wall of the bottom of the waste liquid cavity, a submersible pump is arranged at one corner of the bottom of the waste liquid cavity and connected with a water feeding pipe, and a valve located in the top cover is arranged at the top end of the water feeding pipe. According to the collecting box, liquid generated after the refractometer is cleaned can be recycled, the recycled cleaning liquid can be filtered, the cleaning liquid can be repeatedly used, the refractometer can be repeatedly cleaned, the cleaning effect on the refractometer is improved, and meanwhile the used cleaning liquid is saved.

The utility model discloses an adjustable refractometer, one end of the refractometer body is provided with a prism body and a cover plate capable of pressing liquid to be detected on the surface of the prism body, and the refractometer body is internally provided with a prism support. The outer wall of one end of the refractometer body is provided with a pressing structure for promoting the cover plate to press the prism body, and the outer wall of the refractometer body is in threaded connection with an adjusting screw cylinder for adjusting the height of the prism support; according to the utility model, the adjusting screw for refractometer calibration is improved, the adjusting screw cylinder is used for replacing the adjusting screw, and the limiting structure which can be automatically locked with the adjusting screw cylinder after being lifted upwards is arranged in the adjusting screw cylinder, so that when a prism is adjusted, only the cap at the top of the extension rod needs to be lifted, and the adjusting screw cylinder can be automatically locked with the adjusting screw cylinder. After the extension rod is lifted to the top of the adjusting screw cylinder, the cap is manually rotated to achieve lifting of the adjusting screw cylinder, and compared with a traditional integrated adjusting screw, the adjusting structure does not need extra tools such as a screwdriver.

The invention relates to the technical field of refractometers, and discloses a refractometer calibration device which comprises a base, a supporting transverse plate is arranged above the base, a driving mechanism used for driving the supporting transverse plate to ascend and descend is arranged on the base, a mounting cover is arranged below the supporting transverse plate, and the mounting cover is elastically connected with the supporting transverse plate through an elastic connecting assembly. A mounting shaft is rotationally mounted in the mounting cover, a first motor is fixedly mounted on one side of the mounting cover, and the output end of the first motor is fixedly connected with one end of the mounting shaft; by arranging a plurality of liquid dropping nozzles, the device can drop standard liquid with different concentrations, the standard liquid is dropped by adopting the liquid dropping nozzles, the standard liquid can be accurately dropped onto a detection prism of the refractometer body, and when the dropped standard liquid needs to be switched, a mounting shaft is driven by a first motor to rotate, so that the dropped standard liquid can be switched. The liquid dropping nozzle for dropping liquid towards the refractometer body is replaced, so that different standard liquids are dropped, and the calibration precision is improved.

The present invention relates to the field of liquid refractive index measurement, and particularly to a refractometer and an intelligent cup. The present invention discloses a refractometer and an intelligent cup, wherein the refractometer includes a light source, a prism, a lens unit and a photoelectric sensor. The prism has a contact interface in contact with the liquid to be measured. The light source is a plurality of point light sources arranged in sequence at least in one direction. The light source is configured such that the light emitted by the light source enters the prism through the incident surface of the prism and irradiates the contact interface. The photoelectric sensor is disposed on the image-side focal plane of the lens unit. The light reflected from the contact interface exits the prism through the exit surface of the prism and is imaged on the photoelectric sensor by the lens unit with infinity focusing. The refractometer of the present invention has the advantages of low cost, small size, large measurement range and good robustness.

1. Name of the product under this design: Digital Refractometer (MSDR‑DPlus). 2. Purpose of this design product: This design product is an instrument used in the laboratory to measure the refractive index of liquids. 3. The key point of the design of this product lies in its shape. 4. The picture or photo that best illustrates the design points: three-dimensional picture.

This interference type refractometer comprises a light source (2), a light detector (4) which detects the intensity of received light, an optical system (6; 8; 10; 12) which causes the optical path of light emitted from the light source (2) to branch into a first optical path and a second optical path, then causes the first optical path and the second optical path to merge, and guides interference light of the light from the first optical path and the light from the second optical path to the light detector, a phase modulating unit (18; 20) which is disposed on the first optical path and / or the second optical path and which electrically modulates a phase difference between the light on the first optical path and the light on the second optical path, a control unit (22) which is configured to cause a drive voltage of the phase modulating unit (18; 20) to change over time with a prescribed amplitude and periodicity, to cause the intensity of the interference light detected by the light detector (4, 4') to change over time, a storage unit (24) which stores the intensity of the interference light detected by the light detector (4, 4'), and a calculating unit (26) which performs calculation processing using the intensity of the interference light stored in the storage unit (24), wherein: the control unit (22) is configured to cause the storage unit (24) to store the change over time in the intensity of the interference light in a reference state in which no sample is present on the first optical path and the change over time in the intensity of the interference light in a measurement state in which a sample is present on the first optical path, in association with the change over time in the drive voltage of the phase modulating unit (18; 20); and the calculating unit (26) is configured to obtain an amount of change in the phase of the interference light due to the sample, using a relationship between the change over time in the intensity of the interference light and the change over time in the drive voltage, stored by the storage unit (24), in the reference state, and a relationship between the change over time in the intensity of the interference light and the change over time in the drive voltage in the measurement state, and to obtain the refractive index of the sample on the basis of the amount of change in the phase.

A refractometer comprises a light source module (1), a reflection module (2), a convergence module (3), a photosensitive array (4), a control module and a processor; the control module is used to control the light source module (1) to emit a light beam, the reflection module (2) is used to receive the light beam from the light source module (1), and when the light beam from the light source module (1) meets the total reflection condition in the reflection module, the light beam is totally reflected in the reflection module (2) and incident on the convergence module (3); the convergence module (3) is used to converge the light beam from the reflection module (2) onto the focal plane of the convergence module (3); the photosensitive array (4) is located on the focal plane of the convergence module (3), and the control module is further used to control the photosensitive array (4) to detect the received light beam and output a detection image; the processor is used to determine a brightness mutation boundary in the detection image according to the detection image, and to determine the refractive index corresponding to the brightness mutation boundary according to the position of the brightness mutation boundary.

The present invention comprises: a light source (2); a light detector (4) that detects the intensity of the received light; an optical system (6, 8, 10, 12) that branches an optical path of light emitted from the light source (2) into a first optical path and a second optical path, merges the first optical path and the second optical path, and guides interference light of the light of the first optical path and the light of the second optical path to the photodetector; a phase modulation unit (18, 20) that is disposed on the first optical path and / or the second optical path and that electrically modulates the phase difference between the light of the first optical path and the light of the second optical path; a control unit (22) configured so as to temporally change the intensity of the interference light detected by the photodetectors (4, 4 ') by temporally changing the drive voltage of the phase modulation units (18, 20) at a predetermined amplitude and periodicity, and a control unit (22) configured so as to temporally change the intensity of the interference light detected by the photodetectors (4, 4'); a storage unit (24) that stores the intensity of the interference light detected by the photodetectors (4, 4 '); and a calculation unit (26) that performs calculation processing using the intensity of the interference light stored in the storage unit (24). The control unit (22) is configured so as to compare a temporal change in the intensity of the interference light in a reference state in which no sample is present on the first optical path and a temporal change in the intensity of the interference light in a measurement state in which a sample is present on the first optical path with the phase modulation unit (18; the time change of the drive voltage of the drive circuit (20, 20) is stored in the storage unit (24) in association with the time change of the drive voltage. The calculation unit (26) is configured so as to calculate the time variation of the driving voltage and the time variation of the intensity of the interference light in the reference state stored in the storage unit (24), and to calculate the time variation of the driving voltage in the measurement state by using the relationship between the time variation of the intensity of the interference light in the reference state and the time variation of the driving voltage in the measurement state stored in the storage unit (24). The amount of phase change of the interference light caused by the sample is determined, and the refractive index of the sample is determined on the basis of the amount of phase change.

The invention discloses an organic liquid hydrogen storage online hydrogen content detection device and method. Comprising a detection box, a sealing cup is arranged in the detection box, a sample injection pipe is arranged on the detection box, a quantitative roller is arranged on the sample injection pipe, a plurality of quantitative grooves are formed in the quantitative roller, a temperature control assembly is arranged in the detection box, a weighing assembly is arranged below the sealing cup, a measuring pipe is arranged on the lower portion of the sealing cup, and a temperature control assembly is arranged on the measuring pipe. A refractometer is arranged in the detection box, and a transmission module is further arranged in the detection box. The method disclosed by the invention has the advantages that two groups of data are utilized to establish each stable standard curve at 25-30 DEG C, so that standard data can be checked at each temperature. And then the detection device is used for detecting the sample, the available hydrogen amount is obtained by comparing the standard curve at the corresponding temperature according to the detection temperature, the process of mutual correction at different temperatures is omitted, and errors generated in the process are erased, so that the detection data is more accurate.

An eye-examining apparatus for diagnosing myopia capable of simultaneously measuring the corneal curvature, refractive power, and axial length of the eye to be examined includes a keratometer; a refractometer including an infrared measurement light source, a lens array, and a refractor sensor; an axial length measurement unit including a beam splitter, a reference mirror, and a light detector; and a computation unit configured to calculate the corneal curvature, refractive power, and axial length of the eye to be examined.

The invention discloses a refractometer for measuring liquid concentration and a liquid concentration detection method, the refractometer comprises a light emitting unit, a prism and an imaging unit, the light emitting unit comprises a light source for providing a plurality of probe lights with different wavelengths, and the light incident surface and the light emergent surface of the prism are respectively provided with at least one light incident hole and a plurality of light emergent holes matched with the light incident hole; the detection light forms a virtual light through hole channel in the prism so as to limit the light beam divergence angle of the detection light, the detection light with different wavelengths forms an image array with different spatial positions and / or time differences on the imaging surface of the imaging unit, and the detection light with each wavelength outputs one piece of test data in space or time. According to the invention, a plurality of detection lights with different wavelengths are adopted to correspondingly output a plurality of test data, and a final liquid concentration result is output in a mean value mode, so that the measurement error can be effectively reduced, and the accuracy and the stability of the test result are improved.

The invention discloses a high fructose corn syrup on-line detection device, and relates to the technical field of high fructose corn syrup detection, and the high fructose corn syrup on-line detection device comprises a multi-parameter detection unit which comprises a first on-line near-infrared analyzer, a second on-line near-infrared analyzer, a third on-line near-infrared analyzer, a first refractometer, a second refractometer and a pH sensor; the data acquisition and transmission unit comprises an intelligent gateway and an industrial-grade isolation gatekeeper; the SPC dynamic control unit comprises an industrial server, a communication module and a display terminal; and the abnormity early warning module is integrated in the industrial server and is connected with the audible and visual alarm and the PLC controller. Through multi-sensor cooperative detection, real-time data transmission and SPC dynamic analysis, real-time adjustment of production parameters is achieved, stable product quality is ensured, and meanwhile labor and detection cost is reduced.

The invention provides a capacitive refractometer based on a variable capacitor, and relates to the technical field of atmospheric waveguide parameter detection, and the capacitive refractometer comprises a capacitance detection circuit, a frequency mixing module, a filter circuit and a data processing module which are connected in sequence; wherein the capacitance sensor adopting the variable capacitance is arranged in the capacitance detection circuit; the capacitance value of the capacitance sensor is associated with the entering gas; wherein a detection electric signal influenced by the capacitance value of the variable capacitor is detected and obtained through the capacitance detection circuit, the detection electric signal is subjected to frequency mixing through the frequency mixing module, and the electric signal subjected to frequency mixing is filtered through the filter circuit to generate a stable oscillation signal; the data processing module is also connected with a temperature compensation module; detecting and acquiring a temperature electric signal through a temperature compensation module; the stable oscillation signal and the temperature electric signal are subjected to digital-to-analog conversion and data processing through the data processing module, the refractive index is obtained, and the device has the advantages of being low in cost, high in precision and high in anti-interference capacity.

The utility model relates to a self-cleaning online refractometer which comprises a refractometer body and a flow cell pipeline, a measuring part is arranged at the top of the refractometer, a measuring window is formed in the end of the measuring part, the measuring part is of a columnar structure, the measuring end is obliquely arranged, and the flow cell pipeline is of an approximate Y-shaped three-way structure with the two ends open and the interior hollow. The measuring part of the refractometer main body extends into the side wall of the flow cell pipeline, the inclined surface of the measuring part corresponds to the flowing direction of liquid in the flow cell pipeline, the end part of the measuring part of the refractometer is inclined, the measuring window is formed in the end surface inclined relative to the refractometer, and the measuring part of the refractometer penetrates through the side wall of the flow cell pipeline, so that the liquid in the flow cell pipeline can be measured. The refractometer is arranged in the flow cell pipeline and extends into the flow cell, so that the refractometer extends into the end face in the flow cell pipeline, a preset angle can be formed between the refractometer and the flowing direction of the detection liquid, and the detection window is cleaned through scouring force generated by flowing of the detection liquid.

The utility model discloses a device for measuring the concentration of spinning bath lotion at a constant temperature, belongs to the technical field of spinning bath detection, and aims to solve the problems that a display screen on a refractometer is easily contaminated by dust to influence use and the refractometer is not easy to quickly level according to the flatness of a workbench. A dustproof mechanism is arranged on the outer wall of one end of the refractometer body corresponding to the display screen; a leveling assembly is arranged on the bottom surface of the refractometer body; dustproof protection is carried out on the display screen on the refractometer through the transparent dustproof cover, when the refractometer is used, the inserting plate is pushed upwards to be separated from the limiting sleeve, the transparent dustproof cover is rotated to expose the display screen, the refractometer can be arranged, the wedge plate is pushed to move by rotating the four adjusting screw rods respectively, and the refractometer can be arranged under the running fit of the ball head and the refractometer body. The refractometer body is rapidly leveled, and the problems that a display screen on the refractometer is prone to being contaminated with dust, use is affected, and the refractometer is not prone to being rapidly leveled according to the flatness of the workbench are effectively solved.

The utility model provides a portable water quality salinity detection box, which relates to the salinity detection field, and comprises a water storage box and a refractometer, the water storage box comprises a box body and an upper cover, the box body is used for containing liquid to be detected, the box body and the upper cover are both barrel-shaped structures, the outer side wall of the box body is provided with external threads, and the refractometer is arranged on the box body. External threads are arranged on the inner side wall of the box body, internal threads matched with the external threads are arranged on the inner side wall of the upper cover, the box body and the upper cover are connected in a screwed mode through the external threads and the internal threads, and a sealing piston is arranged at the lower end of the upper cover. The sealing piston can be driven to move up and down in the box body by rotating and screwing the upper cover, so that the salinity change of the to-be-detected liquid in the box body can be observed according to different air pressures, the use is convenient, the structure is small and exquisite, the carrying is convenient, and the production cost is low.

The present invention relates to the technical field of determining the position of a two-phase interface, and more specifically to a method and device for determining a two-phase interface. By reading and recording the refractive index value measured and displayed by an in-situ online refractometer, the position of the interface between two liquids of different phases in a liquid separation tank is determined. The device for determining the two-phase interface provided by the present invention has a simple and clear structure, does not require major improvements to the liquid separation tank, and has a simple installation process. It only requires fixing the light source to the top or bottom of the light source, and ensuring that the light source and the detection component can be correctly aligned with the liquid to be measured. The axis of the detection component is located in the horizontal direction and can be inserted into different liquid levels of the liquid separation tank. Through this principle, the online refractometer can measure the refractive index of the liquid in real time online, thereby obtaining the liquid level information of the liquid. This measurement method is fast, accurate, and continuous, and is very suitable for occasions where the liquid position needs to be monitored in real time.