JPH08297089A - Method and apparatus for detection of component - Google Patents

Abstract

PURPOSE: To provide a method and an apparatus by which a component contained in a sample in an actually existing form is measured by means of light and without destroying the sample. CONSTITUTION: The detection method is composed of a process which uses an optical sensor probe 2 composed of an integrating sphere and in which a sample 7 is compressed, of a process in which the compressed sample is irradiated with light by the probe 2, of a process in which diffused and reflected light from the sample 7 is sampled by the probe 2 and of a computation process in which an optical intensity related to a component to be detected is detected from the sampled light so as to compute the component. The optical sensor probe 2 is composed of the integrating sphere which detects the component contained in the sample in an actually existing form and of light projecting and light receiving fibers 3, 4 (4). On the integrating sphere, an incident port through which the light is introduced from the light projecting fiber 3, is provided at one end in the radial direction, and an irradiation and sampling port 5 by which the sample 7 is irradiated with the introduced light and by which the diffused and reflected light from the sample 7 is sampled is provided at the other end in the radial direction. In addition, the integrating sphere comprises at least one detection port by which the diffused and reflected light is derived to the outside by the light receiving fibers 4, 4'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is based on spectroscopic analysis using near infrared rays, visible light, etc., in which the components contained in the object to be measured remain as they are (this state is hereinafter referred to as "existing form"), that is, without destruction. The present invention relates to an apparatus for measuring, for example, a method and an apparatus for measuring components such as raw leaves, processed tea leaves, rough tea, and water of product tea, which are raw materials for tea production, in an existing form.

[0002]

2. Description of the Related Art Measurement of components such as water contained in tea and food is indispensable for production and quality control.

When the sample is a powder, components such as water contained therein can be measured by near-infrared diffuse reflectance spectroscopy, and several methods have been conventionally used as the measurements by this spectroscopy. . One of them is to fill a measuring container with a sample to be measured, place it on an integrating sphere installed in a spectrophotometer, spectrally collect light from a light source, irradiate the sample, and The diffuse reflection light of is collected and received, and the component contained in the sample absorbs the infrared ray of a specific wavelength, and the attenuation of the light intensity of that wavelength is measured from the received light to measure the sample. Is a method of measuring the components contained in.

Another measurement method is to insert a near-infrared ray into a sample by inserting a fiber probe in which a fiber that guides near-infrared ray into a sample and a fiber that introduces diffuse reflection light from the sample are coaxial. And the diffuse reflection light from the sample is received, and the component contained in the sample is measured from the light intensity as in the above method.

The measurement by such spectroscopic analysis is sufficient if the sample is a powder, and it is not necessary to destroy the sample as in the chemical analysis.

[0006]

However, if the sample is not a powder, the sample must first be dried and ground. In this way, so-called on-line measurement cannot be performed because the component composition of the sample changes, the measurement cost increases, and a crushing step is required. Therefore, for example, when making tea, it is desired to measure the water content of the tea and adjust the drying process so that the water content is within the optimum range. , Crushing it and measuring the water content,
A smooth tea-making process cannot be carried out. Further, some samples are not suitable for crushing depending on the components contained in the samples. Conventional near infrared diffuse reflectance spectroscopy cannot be performed on such samples.

Further, in the measurement using the integrating sphere, an integrating sphere is installed between the sample part and the detecting part of the spectrophotometer, and the measuring container filled with the sample is fixed and measured there, so that the measuring device is complicated. As a result, the size became large, and it was not possible to make online measurements on industrial equipment.

The object of the present invention is to eliminate the above-mentioned drawbacks.
It is an object of the present invention to provide a method and an apparatus for measuring components contained in a sample in an existent form without destroying the sample by using near infrared rays, visible light and the like (hereinafter, simply referred to as light).

[0009]

According to the present invention for achieving the above object, a method for detecting a component contained in an existing sample using an optical sensor probe composed of an integrating sphere includes a step of compressing a sample. A step of irradiating a compressed sample with light by a probe, a step of collecting diffusely reflected light from the sample with a probe, and a step of calculating the component by detecting the collected light.

The optical sensor probe is on an integrating sphere,
It has an entrance for introducing light into one end of its diametrical direction, and irradiates the sample with the light introduced at the other end of its diametrical direction to collect diffused reflected light from the sample. It has a sampling port, and further has at least one detection port for detecting diffuse reflected light.

It is preferable that the compressing step comprises a step of pressing a probe whose irradiation / collecting port is made of an optical material against the sample in the means for sending the sample. It is also desirable that the method comprises the step of feeding between the other feeding means in the vicinity of and above the feeding means. In this case, the other feed means are transparent to light. Further, it is desirable that the compression step comprises a step of vibrating the feeding means.

Further, the compression step may consist of a step of pressing the sample in the cell, or a step of vibrating the cell containing the sample. The surface of the cell that the probe approaches is transparent to light.

When the sample in the cell is irradiated with a wide area and is detected, it is desirable to further include a step of moving the cell and the probe relatively.

The light incident on the sensor probe is preferably divided into absorption light having a wavelength absorbed by the component to be detected and reference light having a wavelength not absorbed by the component to be detected and arranged in series. At this time, the calculation step calculates the component based on the intensity of the absorbed light and the intensity of the reference light.

An apparatus for detecting a component contained in an existent sample of the present invention has a light source and an entrance for introducing light into one end in the diameter direction, and introduces the introduced light into the sample. Sensor probe which has an irradiation / collection port for irradiating the sample to collect diffused reflected light from the sample at the other end in the diameter direction, and further has at least one detection port for detecting diffused reflected light. A detector for detecting the light from the detection port, a calculating means for calculating the component based on the detected value, and a compressing means for compressing the sample.

The compressing means may comprise means for pressing a probe whose irradiation / collecting port is made of an optical material against the sample, or may comprise a pair of sample feeding means arranged opposite to each other. Here, the feeding means, to which the sensor probe is in proximity, is transparent to light.

The sample compression means may be vibrable.

The sample compression means preferably comprises means for pressing the sample in the cell, the surface of the cell facing the probe being transparent to light.

When performing detection on the entire sample in the cell, it is desirable to further include means for moving the cell and the probe relative to each other.

The light is incident on the sensor probe by means of dividing the light into absorption light having a wavelength absorbed by the component to be detected and reference light having a wavelength not absorbed by the component to be detected and providing them in series. At this time, the calculation means calculates the component based on the intensity of the absorbed light and the intensity of the reference light.

It is desirable that a collimator is provided at the entrance so that the light introduced by the projecting optical fiber is converted into a condensed light flux and applied to the sample. Further, it is desirable that the light passes through a rod-shaped member made of an optical material that extends through the entrance port to the irradiation / collection port.

A detector for detecting the intensity of light may be directly attached to the detection opening of this probe.

[0023]

The compressed sample is irradiated with light by an optical sensor probe, diffuse reflected light whose intensity is changed by being absorbed by the component is detected, and the component is detected based on the diffuse reflected light.

The sample is compressed by pressing the photosensor probe directly onto the sample.

The sample is compressed by vibrating the feeding means, supplying the sample between the pair of feeding means, or pressing the sample in the cell.

By relatively moving the cell and the optical sensor probe, the sample in the cell can be irradiated with light over a wide range.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 schematically shows a substantially rectangular parallelepiped housing 1 in which an optical sensor probe 2 used in the measuring apparatus of the present invention is housed. The sensor probe 2 is composed of an integrating sphere as described below, and is provided with a projecting optical fiber 3 for guiding light inside and a light receiving fiber 4, 4'for guiding light out of the optical fiber 3. An irradiation / collection port 5 (see FIG. 2) is provided at the bottom of the sensor probe 2, and that portion is exposed outside the bottom of the housing 1.

The housing 1 is suspended by a wire, and the tip of the wire is connected to elevators 6 and 6'mounted on an external frame. The elevator is composed of a coil and a plunger, and pulls up the plunger by a magnetic force generated by energizing the coil. Therefore, the elevator can move the housing 1 up and down to move it away from or approach the sample 7. The elevator is not limited to this as long as it can raise and lower the housing. For example, a pneumatic cylinder may be used.

In order to measure the components of the sample according to the present invention, it is impossible to obtain a satisfactory measured value when the sample is full of gaps.
At the time of measurement, the housing 1 is lowered and brought into contact with the sample, and further, the weight of the sensor probe 2 and further the weight (see FIG. 1) are adjusted as necessary, so that the sample 7 is pressed so as to be suitable for the measurement. .

FIG. 2 shows a sectional view of the sensor probe 2. An entrance port 10 for introducing light is provided at the apex of the sensor probe 2, and a collimator lens system 11 is installed at the entrance port 1.
It is located outside of it to match zero. The light guided from the projection optical fiber 3 becomes a condensed light beam by the collimator lens system 11.

At the bottom of the sensor probe 2, that is, at the position facing the entrance 10, circular irradiation made of quartz.
A sampling port 5 is provided. The material of the irradiation / collection port 5 is not limited to quartz, but may be an optical material such as glass.
The light incident inside passes through this irradiation / collection port and is irradiated onto the sample. The diameter of the irradiation / collection port 5 is preferably φ + 6 mm, where φ is the diameter of the light that passes through the irradiation / collection port 5 through the collimator lens 11 and is irradiated on the sample 7.

The light emitted from the irradiation / collection port 5 is applied to the sample and enters the sample. Then, the diffuse reflection light 12 from the sample is collected by the irradiation / collection port and enters the sensor probe 2. Here, a component in the sample absorbs light of a specific wavelength when the light is diffusely reflected in the sample. Therefore, the intensity of light of that wavelength is significantly attenuated and enters the sensor probe 2. The intensity of light having a wavelength that is not involved in the absorption enters the sensor probe 2 with almost no attenuation. Light of such a wavelength that is not attenuated is used as reference light.

The upper hemisphere of the sensor probe 2 has a detection port 1 for guiding the diffuse reflection light 12 to the outside in order to detect it.
4, 14 'are provided. The diffuse reflection light 12 that has entered from the irradiation / collection port 5 is reflected one after another by the sensor probe 2, that is, the inner wall of the integrating sphere, and reflected toward the detection port 14 passes through the detection port 14 and is connected. It is led out through the light receiving fibers 4, 4 '. It should be noted that some of the light that enters the inside of the entrance 10 is specularly reflected by the surface of the irradiation / collection port 5 and the interface with the sample and does not enter the sample 7, but such light is an integrating sphere. There is almost nothing that reflects on the inner surface of the and goes to the detection port. As such light is repeatedly reflected, the irradiation / collection port 5
The sample 7 is irradiated with the light passing through and becomes diffuse reflected light.

In this embodiment, the case where there are two detection ports is illustrated, but when the direction of diffuse reflected light is uniform, the number of detection ports may be one. On the other hand, if the uniformity of the direction is poor, it is desirable to further provide a detection port.

In FIG. 2, the sample 7 is placed on a conveyor 8 for feeding in and out. It is desirable that the speed of the conveyor be appropriately adjusted according to the detection light and the state of the sample.

FIG. 3 shows a modification of the sensor probe. Here, the same reference numerals as those in FIG. 2 are attached to the corresponding elements. In this sensor probe 30, the tip of a projection optical fiber 31 passes through the entrance 10 and extends to the irradiation / collection port 5 and is embedded therein. When the fiber 31 is extended in this manner, the incident light surely passes through the irradiation / collection port and is irradiated onto the sample 7. Further, the specular reflection light generated at the interface between the fiber and the sample is not scattered inside the sensor probe 30. Therefore, the accuracy of this embodiment is very high. Further, by housing this fiber 31 in a stainless steel cylinder, it is possible to prevent light from leaking out from the fiber 31. Further, when the outer circumference of the stainless steel cylinder is plated with gold, aluminum or the like, diffuse reflection light that has entered the sensor probe 30 is effectively reflected in the sensor probe 30, and the detection port 14
Can lead to.

In this embodiment, the fiber 31 is a part of the throwing optical fiber, but the present invention is not limited to this, and a rod-shaped optical material such as quartz is provided between the entrance and the irradiation / collection entrance.
It may be configured by connecting a throwing optical fiber to the upper end of the rod-shaped member.

FIG. 2 (or FIG. 3) is as shown in FIG.
It is illustrated that the sensor probe 2 is housed in the housing 1 and the sensor probe 2 is directly pressed against the sample to compress the sample and detect the components.
As will be described with reference to FIG. 6, when the probe is brought close to the sample via a conveyor for pressing the sample and a holding plate (or cell), the irradiation / collecting port 5 needs to be made of an optical material such as quartz. Instead, it may be a simple opening.

4 to 6 show another sample compression method.

In FIG. 4, as shown in FIGS. 1 to 3, the sample is sent in and out by a conveyor 40, but another conveyor 41 is arranged adjacent to the conveyor 40, and the sample is supplied therebetween. To do. Conveyors 40 and 4
Between 1 the sample is compressed and has no gaps. Here, as the belt of the belt conveyor 41, a material that is substantially transparent to light or a net-shaped belt is used. The sensor probe 2 is arranged near the belt conveyor 41.

As shown in FIG. 4, the compressed sample is irradiated with light from the sensor probe 2, and the diffuse reflected light from the sample is collected by the sensor probe 2 and collected.

Instead of the other belt conveyors described above, a vibration conveyor or the like which sends out the sample while vibrating it may be used. However, the vibration at this time needs to be such that the sample becomes dense. Even if the sample becomes dense due to vibration, it is difficult to measure a sample that vibrates during measurement, so the vibration is stopped.

In FIG. 5, the sample is filled in the cell 42 and compressed. At this time, the compression may be performed by pressing the sample with a pressing plate or by vibrating the cell 42. Alternatively, the sensor probe itself may be pressed down.

In FIG. 6, a quartz cell 43 is filled with a sample and pressed from above with a glass pressing plate. The material of this cell is not limited to quartz, and an optical material such as glass can be used. The pressure to be applied is appropriately set depending on the sample, but when the sample is tea leaves, it is not limited to this, but when it is 20 to 30 g / cm 2, accurate measurement can be performed.

The sensor probe is arranged near the bottom surface.
Since the cell is made of an optical material, the light from the sensor probe 2 passes through the cell and enters inside, and the diffusely reflected light from the sample passes through the cell and enters the sensor probe.

To obtain an average measurement for a sample,
The sensor probe may be fixed, and the cell 43 may be rotated and moved by the conventional rotating means and moving means. On the contrary, the cell is fixed and the sensor probe 2 is placed along the bottom of the cell.
May be rotated or moved.

When the sensor probe 2 is moved in the radial direction with respect to the center of the cell simultaneously with the rotation of the cell 43, it is possible to easily irradiate, sample, and measure the entire sample in the cell.

It is desirable that the sensor probe is brought as close as possible to the bottom surface of the cell so that other light does not enter in order to measure without noise. When measuring the water content, attach the sensor probe 2 from the bottom of the cell.
It was possible to obtain an acceptable measurement value even when the measurement value was placed at a position of about mm.

FIG. 7 is a block diagram showing an embodiment of the measuring apparatus. The measuring device basically includes a light source unit 50, a sampling unit 60, and a detection unit 70.

The light source 51 housed in the lamp house 52 in the light source section 50 is a light source for generating light, preferably near infrared rays, for example, a halogen lamp, and is connected to the power source 53. The light from the light source 51 passes through the chopper 54, is condensed by the lens, and is sent to the projection optical fiber 3.

As shown in FIG. 8, the chopper 54 has a disk shape, is provided with a plurality of openings, and is provided with a filter 55. The filter 55 allows light having a specific wavelength to pass therethrough. In this embodiment, the filter 55 allows light having a specific band centered at the maximum wavelength absorbed by the component to be measured contained in the sample to pass therethrough. And a filter that passes the reference light in a specific band centered on a wavelength that is not absorbed by the component to be measured contained in the sample are alternately arranged, but it is not necessary to alternately arrange them in this way and the same function is achieved. You may continue with the filter.

When the chopper 54 is rotated by the chopper drive section 54 '(motor) connected to the power source 53,
The light passes through the filters one after another, and becomes a pulsed light having a predetermined wavelength, and sequentially emerges.

The light passing through the projection optical fiber 3 is incident on the sensor probe 2 in the sampling section 60. Then, the collected light is collected through the light receiving fiber 4 and sent to the detection unit 70.

The sampling unit 60 includes, for example, an elevator as shown in FIG. 1, another belt conveyor as shown in FIG.
The drive unit 61 is represented by a drive device for rotating the cell and a drive device for moving the sensor probe.

The collected light is input to the detector 72 via the condenser lens 71. The detector 72 is a controller 73
The temperature is controlled by and the intensity of the absorbed light of the wavelength absorbed by the component to be measured and the intensity of the reference light of the wavelength not affected by the component to be measured are sequentially detected from the input light.

The output of the detector 72 is input to the computer 74. The synchronization signal from the chopper 54 and the signal from the integrating sphere (sensor probe) are input to the computer 74, the components to be detected are calculated, and the CR
A quantity and a graph are displayed on T.

In this device, the concentration of the component to be detected can be measured and measured by appropriately selecting the filter that allows the specific wavelength absorbed by the component to pass.

As an example of the filter for measuring the water content in samples such as fresh leaves, processed tea leaves, rough tea and product tea, those having the following central wavelengths can be mentioned. When the concentration of water contained in tea is high, the center wavelength is 1200 nm, and when the concentration of water is relatively low, the center wavelength is 1450 nm,
When the concentration of water is low, the filter has a center wavelength of 1940 nm. In this way, the central wavelength is changed depending on the concentration of water, for example, when the concentration of water is high,
Using a filter with a center wavelength of 1940 nm,
This is because the light intensity to be detected is significantly attenuated and saturated, and the water content cannot be measured.

At this time, the center wavelengths of the filters are 1270 nm and 214 as reference wavelengths that do not absorb the moisture.
A 0 nm one is used.

By increasing the number of filters, components other than water, such as neutral detergent fibers (total fibers), total nitrogen, theanine, etc., can be simultaneously detected.

In the above-mentioned embodiment, the sensor probe 2 and the detecting section 70 are connected by the light receiving fiber. However, as shown in FIG. 9, the detector 72 'is directly attached to the detecting port of the sensor probe 2. May be.

[0062]

According to the method of the present invention, a compressed sample is irradiated with light by an optical sensor probe, and the optical sensor probe impinges on the sample to absorb diffuse reflected light whose intensity is changed by the component. Can be detected. Therefore, not only a powder sample but also a non-powder sample can be measured in the existing form without destroying the components contained in the sample.

If the sample is compressed, even if it moves, it has almost no effect on the measurement, and therefore, online measurement can be performed.

When the sample is filled in the cell, by relatively moving the cell and the optical sensor probe, it is possible to irradiate and sample the sample in the cell over a wide range, and highly accurate measurement can be performed.

[Brief description of drawings]

FIG. 1 shows a state in which a housing having a sensor probe of the present invention inside is pressed against a sample.

FIG. 2 shows a schematic cross-sectional view of the sensor probe of the present invention.

FIG. 3 shows a schematic sectional view of a sensor probe according to another embodiment of the present invention.

FIG. 4 shows a schematic diagram of an apparatus for compressing a sample.

FIG. 5 shows a schematic diagram of another device for compressing a sample.

FIG. 6 shows a schematic diagram of another device for compressing a sample.

FIG. 7 is a block diagram showing an embodiment of the measuring apparatus of the present invention.

FIG. 8 is a schematic view of a light source unit.

FIG. 9 shows a partially enlarged view of another sensor probe used in the present invention, in which a detector is attached to a detection port.

[Explanation of symbols]

 1 Housing 2 Sensor probe 3 Optical fiber 4, 4'Light receiving fiber 5 Irradiation / sampling port 6, 6 'Elevator 7 Sample 8 Belt conveyor 11 Collimator 10 Inlet port 12 Diffuse reflected light 14, 14' Detection port 30 Sensor probe 31 Optical fiber 40 Conveyor 41 Conveyor 42 Cell 43 Cell

Claims (21)

[Claims] 1. A method for detecting a component contained in an existent sample using an optical sensor probe comprising an integrating sphere, comprising the steps of compressing the sample, and applying the probe to the compressed sample. A step of irradiating light, a step of collecting diffusely reflected light from the sample with the probe, and a step of calculating the component by detecting the collected light, the optical sensor probe, On the integrating sphere, one end in the diametrical direction has an entrance for introducing the light therein, and the light introduced at the other end in the diametrical direction is irradiated to the sample, and diffuse reflection from the sample is performed. The method according to claim 1, further comprising an irradiation / collection port for collecting light, and further having at least one detection port for detecting the diffuse reflection light. 2. The method according to claim 1, wherein the sample is moved by a feeding means. 3. The method according to claim 2, wherein the irradiation / collecting port of the probe is made of an optical material, and the compressing step includes a step of pressing the probe against the sample in the feeding means. , A method characterized by the following. 4. The method according to claim 2, wherein the compressing step comprises the step of supplying between the feeding means and another feeding means disposed in close proximity thereto. A method which is transparent to the light. 5. The method of claim 2, wherein the compressing step comprises the step of vibrating the feed means. 6. The method of claim 1, wherein the compressing step comprises pressing a sample in a cell, the probe approaching surface of the cell transparent to the light. There is a method. 7. The method of claim 1, wherein the compressing step comprises vibrating a cell containing the sample. 8. The method of claim 7, further comprising the step of moving the cell and the probe relative to each other. 9. The method according to claim 1, wherein the absorption light having a wavelength absorbed by the component to be detected and the reference light having a wavelength not absorbed by the component to be detected are separated and arranged in series. And irradiating the sample with the light, and calculating the component based on the intensity of the absorbed light and the intensity of the reference light. 10. The method according to claim 1, wherein a collimator provided at the entrance makes the light introduced by the projecting optical fiber into a condensed light beam and irradiates the sample. And how to. 11. The method according to claim 1, wherein the light passes through a rod made of an optical material that extends through the entrance and reaches the irradiation / collection entrance. 12. An apparatus for detecting a component contained in an existing sample, comprising: a light source; and an entrance for introducing the light into one end in a diameter direction, the light being introduced. An sphere having an irradiation / collecting port for irradiating a sample and collecting diffusely reflected light from the sample at the other end in the diameter direction, and further having at least one detection port for detecting the diffusely reflected light. An apparatus comprising: a sensor probe including: a detector that detects light from the detection port; a calculating unit that calculates the component from the detected value; and a compressing unit that compresses the sample. 13. The apparatus according to claim 12, wherein the irradiation / collection port of the probe is made of an optical material, and the sample compressing means is means for pressing the probe against the sample. apparatus. 14. The apparatus according to claim 12, wherein the sample compressing means comprises a pair of sample feeding means opposed to each other, and the sample is compressed by feeding the sample between the sample feeding means. A device characterized by the above. 15. The apparatus according to claim 12, wherein the sample compressing means can vibrate, the probe approaches, and the sample feeding means is transparent to the light. Device to do. 16. The apparatus according to claim 12, wherein the sample compressing means comprises means for pressing a sample in a cell, and the surface of the cell facing the probe is transparent to the light. A device characterized by: 17. The apparatus according to claim 16, further comprising means for relatively moving the cell and the probe. 18. The apparatus according to claim 12, wherein the absorbed light having a wavelength at which a component to be detected absorbs the light,
Separated into a reference light of a wavelength that the component to be detected does not absorb,
The device is characterized in that the light is made incident on the sensor probe by means of providing in series, and the calculating means calculates the component based on the intensity of the absorbed light and the intensity of the reference light. 19. The apparatus according to claim 12, wherein the collimator provided at the entrance port irradiates the sample with the light introduced by the projection optical fiber as a condensed light beam. And the device. 20. The apparatus according to claim 12, wherein the light passes through a rod made of an optical material that extends through the entrance to the irradiation / collection entrance. 21. The apparatus according to claim 12, wherein the detector is attached to a detection opening of the probe.
A device characterized by the above.