CN222166858U - Alcohol concentration measuring device based on grazing incidence method - Google Patents

Abstract

The present application discloses an alcohol concentration measuring device based on grazing incidence method in the field of solubility detection devices, which includes a light source, which emits light used for testing; an optical device, which is arranged on the optical path of the light emitted by the light source and converges the light; a spectrometer, which is arranged on the rear side of the optical device, and the light focus converged by the optical device passes through the spectrometer, and disperses the light passing through the spectrometer; an optical signal receiving and processing unit, which is used to detect the light passing through the spectrometer; when in use, a test liquid is added to the spectrometer, and after the light is incident at a fixed point and passes through the liquid, grazing incidence is formed on the spectrometer, and the angles of the outgoing light rays are all within the critical angle, forming a field of view with a light-dark boundary with the critical angle as the boundary, that is, a semi-shaded field of view, which will be captured by the optical signal receiving and processing unit; the semi-shaded field of view will not be affected by bubbles and impurities in the solution, but is only related to the boundary, has low requirements on the sample, and ensures detection accuracy.

Description

Alcohol concentration measuring device based on grazing incidence method

Technical Field

The application relates to the technical field of liquid solubility detection devices, in particular to an alcohol concentration measurement device based on a grazing incidence method.

Background

Alcohol and water have different refractive indexes, and the alcohol concentration and the refractive index of the alcohol solution are in a linear relation in a certain concentration range, so that the concentration of the alcohol solution can be accurately measured by measuring the refractive index of the alcohol solution. The refractive index is generally measured by means of the refractive characteristic of light, and conventional measurement methods include a minimum deflection angle method, a total reflection method, a grazing incidence method and the like. Since refractive index measurement can obtain higher measurement accuracy, measuring refractive index with high accuracy becomes an effective method for identifying composition of a substance, determining purity and concentration of a substance, and evaluating quality of a substance. In practice, the minimum deflection angle method requires that the sample be processed into a prismatic shape, typically used to measure solid samples. Refractive methods generally use the property of total reflection of light at two interfaces to make refractive index measurements. The measurement accuracy depends on the measurement accuracy of the position of the half shadow field after total reflection. The measurement of the precision is affected by the monochromaticity of incident light, the infiltration degree of an interface, the dispersion characteristic of a reflection interface, the displacement measurement precision of a detector and other factors. The special high-precision refractometer is high in price and complex in operation, and needs to be operated and analyzed by a professional, and most refractometers have high requirements on the sample, and impurities and bubbles can influence the measurement result.

Disclosure of utility model

The application aims to provide an alcohol concentration measuring device based on a grazing incidence method, which aims to solve the defects that most refractometers in the prior art have higher requirements on a sample, the measuring result is possibly influenced by impurities and bubbles, and the detection precision cannot be ensured.

In order to solve the technical problems, the application is realized by adopting the following technical scheme:

an alcohol concentration measuring device based on grazing incidence method comprises

A light source that emits light for testing;

An optical device disposed on an optical path of the light emitted from the light source and converging the light;

A beam splitter which is disposed on a rear side of the optical device, and through which a light focal point converged by the optical device passes, and which disperses light passing through the beam splitter;

And an optical signal receiving and processing unit configured to detect light passing through the optical splitter.

According to a further scheme of the application, the optical device comprises a collimating lens and a converging lens which are arranged at intervals and coaxially, a light-reducing polarizer is arranged on the light path between the collimating lens and the converging lens, and the light-reducing polarizer can move along the direction of the light path.

In a further aspect, the light-reducing polarizer includes an attenuation sheet and a polarizing sheet that are disposed at intervals and coaxially, and the light is sequentially transmitted through the attenuation sheet and the polarizing sheet.

According to a further scheme of the application, the beam splitter comprises a first prism and a second prism, a shading sheet is connected between opposite prism faces of the first prism and the second prism, and a liquid storage area is formed between the first prism and the second prism and the shading sheet.

In a further scheme, the shading sheet is U-shaped.

According to a further scheme of the application, the optical signal receiving and processing part comprises an optical filter, a charge coupler and a computer;

The optical filter is arranged on one side of the charge coupler, which faces the light splitting body, the charge coupler is electrically connected with the computer, light emitted by the light splitting body is displayed on the optical filter and captured by the Charge Coupler (CCD), and the computer calculates through the relation between displacement and refractive index.

According to a further scheme of the application, the center of the light source, the center of the optical device and the center of the beam splitter are coaxially arranged.

According to a further scheme, the light source is an LED, and the LED is low in price.

Compared with the prior art, the application has the beneficial effects that:

When the application is used, the test liquid is added into the beam splitter, after the light is incident at a fixed point and penetrates through the liquid, glancing incidence is formed on the beam splitter, the angles of emergent light rays are all within a critical angle, a field of view with the critical angle as a boundary to form a bright-dark boundary, namely a half shadow field of view, which can be captured by the light signal receiving and processing part, is not influenced by bubbles and impurities in the solution, is only related to the boundary, has lower requirements on a sample, and ensures the detection precision.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present application;

FIG. 2 is a schematic diagram of the split-beam body grazing incidence half-shadow field of view in the present application;

Wherein the method comprises the steps of

1. A light source; 2, a collimating lens, 3, a neutral attenuation sheet, 4, a polaroid, 5, a condensing lens, 6, a first prism, 7, a shading sheet, 8, a second prism, 9, an optical filter, 10 and a charge coupler.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application, its application, or uses.

Referring to FIG. 1, in this embodiment, a grazing incidence method-based alcohol concentration measuring device is disclosed, comprising

The light source 1 emits light for testing, the optical device is arranged on an optical path of the light emitted by the light source 1 and collects light, the optical device is arranged on the rear side of the optical device, a light focus collected by the optical device passes through the inside of the optical device and disperses the light passing through the optical device, the light signal receiving and processing part is used for detecting the light passing through the optical device, and the light source 1 uses an LED light emitting diode and generates a white light source.

The structure in the device is specifically described below;

continuing to observe fig. 1, the optical device in this embodiment includes a collimator lens 2 and a converging lens 5 that are disposed at intervals and coaxially, and a light-reducing polarizer is disposed on an optical path between the collimator lens 2 and the converging lens 5, and the light-reducing polarizer is composed of an attenuation sheet 3 and a polarizing sheet 4 that are disposed at intervals and coaxially, and light is sequentially transmitted through the attenuation sheet 3 and the polarizing sheet 4.

The beam splitter in this embodiment includes a first prism 6 and a second prism 8, a light shielding sheet 7 is connected between opposite prism surfaces of the first prism 6 and the second prism 8, a liquid storage area is formed between the first prism 6 and the second prism 8 and the light shielding sheet 7, and liquid alcohol is contained in the liquid storage area, wherein the light shielding sheet 7 is in a U shape, the collimating lens 2 and the converging lens 5 adopt lenses 2 and 5 with focal lengths of 50mm and diameters of 10mm, and an angle for generating converging light is about 18 degrees.

The optical signal receiving and processing part in the embodiment comprises an optical filter 9, a charge coupler 10 and a computer, wherein the optical filter 9 is arranged on one side of the charge coupler 10 facing the beam splitter, and the charge coupler 10 is electrically connected with the computer.

When the light source is used, the LED light-emitting diode generates a white light source, the collimating lens 2 emits a collimated light beam, the light intensity is regulated through the attenuation sheet 3, the polarization of the light is changed through the polarization sheet 4, and the light is converged through the converging lens 5 and is incident into the light-splitting sample cell. The incident light is transmitted through the first prism 6 to enter the liquid film at a fixed point, and the focus falls at the interface of the first prism 6 and the liquid level. The incident solution light forms grazing incidence at the shading sheet 7, and the light smaller than the critical angle exits to form a half-shadow field of view. The outgoing light is emitted from the second prism 8, enters the optical signal receiving processing system, is captured by the CCD10, and is calculated by a computer through the relation between displacement and refractive index.

The displacement versus refractive index relationship with reference to fig. 2 is:

Wherein the refractive index of the two prisms is The refractive index of the liquid to be measured isThe refractive index of air isAnd (2) and. Fixed incident point A, shading sheet position B (critical of light emergent liquid), emergent point C of second prism 8. A vertical distance to the light shielding sheet 7B is projected on the image screen as O and is set as displacement origin, and the thickness of the liquid film isDistance B from the exit face of the second prism 8The emergent surface of the second prism 8 is parallel to the image screen and has a distance of。

The computer program calculates the refractive index of the solution to be measured through the relation between the displacement and the refractive index, and further calculates the solution concentration through the empirical formula of the refractive index and the solution concentration of different solutions, and the prior art is not repeated here.

Detecting alcohol solution with certain concentration;

And 1, constructing a device, and adjusting an optical main shaft to be horizontal, so that two triangular prisms (a first prism 6 and a second prism 8) and a CCD (charge coupled device) are positioned appropriately, and the clearest half-shadow field of view can be obtained.

And 2, preparing pure water and preparing 3 alcohol solutions with different concentrations in a normal temperature environment, and recording the corresponding alcohol solution concentrations. Pure water was used as a reference liquid. And 3 kinds of calibration solutions are sequentially injected between the double triangular prism slits according to the sequence from low concentration to high concentration, and after the solutions are stabilized, the positions of the cut-off lines are recorded and are respectively compared with the positions of the cut-off lines of the reference solution. The computer uses a cubic function to fit the displacement of the cut-off and the solution concentration curve as a calibration curve.

And 3, injecting reference liquid pure water into a sample groove (a liquid storage area between the first prism 6 and the second prism 8), and recording the position of a cut-off line after the solution is stable.

And 4, injecting the liquid to be measured into the sample tank, recording the position of the cut-off line of the liquid to be measured after the liquid is stable, and comparing the position of the cut-off line with the position of the cut-off line of the reference liquid. And calculating the concentration of the solution to be measured by using a calibration curve through a computer.

In summary, the novel device for measuring the concentration of the alcohol solution uses the LED as the light source 1 for wide spectrum incidence, uses the standard two prisms as the container, has low cost and compact structure, is easy to realize device miniaturization, uses the grazing incidence method as the main principle of the device, has simple structure and lower requirements on samples, strengthens the contrast ratio of a half shadow field of view through the improvement measures of the polaroid 4, the shading sheet 7 and the like, improves the measurement accuracy, has simple operation process, has low requirements on environment and is easy to use.

It will be appreciated by those skilled in the art that the present application can be carried out in other embodiments without departing from the spirit or essential characteristics thereof. Accordingly, the above disclosed embodiments are illustrative in all respects, and not exclusive. All changes that come within the scope of the application or equivalents thereto are intended to be embraced therein.

Claims (6)

1. A device for measuring alcohol concentration based on grazing incidence method, characterized in that it includes A light source (1) that emits light used for testing; An optical device arranged on the optical path of the light emitted by the light source (1) and focusing the light; A beam splitter is arranged at the rear side of the optical device, and the focus of light gathered by the optical device passes through the inside of the beam splitter, and the light passing through the beam splitter is dispersed; an optical signal receiving and processing unit, which is used to detect the light passing through the spectrometer; The optical device comprises a collimating lens (2) and a converging lens (5) which are spaced apart and coaxially arranged, a light-dimming polarizer being provided on the optical path between the collimating lens (2) and the converging lens (5); the beam splitter comprises a first prism (6) and a second prism (8), a light shielding sheet (7) being connected between the opposing prism faces of the first prism (6) and the second prism (8), and a liquid storage area being formed between the first prism (6) and the second prism (8) and the light shielding sheet (7). 2. The alcohol concentration measuring device based on grazing incidence method according to claim 1 is characterized in that: The light-reducing polarizer comprises an attenuation plate (3) and a polarizer (4) which are spaced apart and coaxially arranged, and the light passes through the attenuation plate (3) and the polarizer (4) in sequence. 3. The alcohol concentration measuring device based on the grazing incidence method according to claim 1 is characterized in that the shading sheet (7) is U-shaped. 4. The alcohol concentration measuring device based on the grazing incidence method according to claim 1, characterized in that the optical signal receiving and processing unit comprises a filter (9), a charge coupled device (10) and a computer; The optical filter (9) is mounted on a side of the charge coupler (10) facing the beam splitter, and the charge coupler (10) is electrically connected to the computer. 5. The alcohol concentration measuring device based on the grazing incidence method according to claim 1 is characterized in that the light source (1), the optical device, and the center of the spectrometer are coaxially arranged. 6. The alcohol concentration measuring device based on the grazing incidence method according to any one of claims 1 to 5, characterized in that the light source (1) is an LED light emitting diode.