JP2003042933A - Instrument for measuring particle-size distribution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a particle-size distribution measuring instrument, capable of separating a discharged sample solution into a dispersive medium and a measuring objective sample, capable of removing the measurement object sample and the dispersive medium bringing environmental pollution from a waste liquid, and capable of recovering the valuable measurement object sample. SOLUTION: In the particle size distribution measuring instrument 1, the measurement object samples S1 -Sn are mixed into the dispersive media 4a, 4b under agitation, to prepare the sample solution S, and the intensities of transmitted light Lt and scattered light Ls, generated when the sample solution S is irradiated with light, are measured to a particle size distribution of the measurement object samples. The instrument 1 is provided with a waste liquid treating part 17 for separating the dispersive media 4a, 4b and the measuring objective samples S1 -Sn in a flow passage 16, for discharging the sample solution S after the measurement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle size distribution measuring device such as a laser diffraction / scattering type particle size distribution measuring device for measuring the particle size distribution of powder particles.

[0002]

2. Description of the Related Art Conventionally, in a laser diffraction / scattering type particle size distribution measuring apparatus, a sample liquid to be measured is mixed and stirred in a dispersion medium to generate a sample liquid, and the sample liquid is circulated in a circulation system including cells. In this state, there is a particle size distribution measuring device for measuring the particle size distribution of a sample to be measured by measuring the intensity of transmitted light and scattered light generated when the cell is irradiated with light. A general particle size distribution measuring device is configured so that the sample liquid after the measurement is discharged as a waste liquid and is not left in the circulation system.

[0003]

However, some of the samples to be measured may contain heavy metals such as lead, which is an environmental pollutant, and it is not possible to directly discharge the sample liquid containing such samples to be measured. However, there was a problem from the viewpoint of preventing environmental pollution. Moreover, not only the precious metals such as gold and platinum, but also important samples related to trade secrets may be contained in the sample to be measured,
In some cases, the dispersion medium also contains a substance that may pollute the environment, such as an organic solvent.

Therefore, the operator once collects the discharged sample liquid using a plastic container or the like and then filters it to take out the sample to be measured from the collected sample liquid or to collect the sample to be measured. The removed dispersion medium such as the organic solvent was sometimes collected. However, in this case, there is a problem that extra time and labor are required for the recovery work, and a troublesome waste liquid treatment needs to be performed in order to reliably recover the sample to be measured and the dispersion medium.

According to the present invention, in a laser diffraction / scattering type particle size distribution measuring apparatus, a discharged sample liquid is separated into a dispersion medium and a measurement target sample, and the measurement target sample and the dispersion medium causing environmental pollution are removed from the waste liquid. Alternatively, it is an object of the present invention to provide a particle size distribution measuring device capable of recovering a valuable sample to be measured from a waste liquid.

[0006]

In order to achieve the above object, the particle size distribution measuring apparatus of the present invention comprises mixing and stirring a sample to be measured with a dispersion medium to generate a sample liquid, and irradiating the sample liquid with light. In a particle size distribution measuring device that measures the particle size distribution of the sample to be measured by measuring the intensity of transmitted light and scattered light generated when the dispersion liquid and the object to be measured are in the flow path for discharging the sample liquid after measurement. A feature is that a waste liquid processing section for separating the sample is provided. (Claim 1)

In the particle size distribution measuring apparatus, since the dispersion medium and the sample to be measured can be separated by the waste liquid processing section provided in the flow path for flowing the sample liquid as the waste liquid, by storing the separated dispersion medium. The dispersion medium can be recovered very easily. Further, the separated sample to be measured can be similarly easily recovered.

When the waste liquid processing section has a dispersion medium recovery section for recovering the separated dispersion medium and making it reusable (claim 2), by reusing the dispersion medium,
The cost for measuring the particle size distribution can be suppressed. In particular, in the case of a dispersion medium that may adversely affect the environment such as an organic solvent, minimizing its use can contribute to environmental protection.

When the waste liquid treatment section has a measurement object sample recovery section for recovering the separated measurement object sample (Claim 3), the measurement object sample can be reused. In this case, it can contribute to cost reduction. Further, when the sample to be measured is a compound such as a newly developed drug which is related to trade secrets, the confidentiality can be kept by surely collecting it.
In addition, when the sample to be measured is an environmental pollutant,
By reliably collecting this, it can contribute to environmental protection. Further, the same sample to be measured can be dispersed in different dispersion media for measurement, or can be repeatedly analyzed under various different conditions such as different temperatures and pHs.

When the waste liquid treating section has a filter having a finer mesh than the sample to be measured in order to separate the sample to be measured from the dispersion medium (Claim 4), the sample to be measured can be reliably made with an extremely simple structure. The sample can be separated, and the separated sample to be measured can be collected simultaneously with the replacement of the filter.

[0011]

1 is a diagram showing the overall structure of a laser diffraction / scattering type particle size distribution measuring apparatus 1 according to an embodiment of the present invention, in which 2 is a measuring unit and 3 is this measuring unit 2. Is a processing unit such as a personal computer connected to the communication line.

The measuring unit 2 has, for example, two types of dispersion media 4a, 4
b, an automatic dispersion medium supply unit (hereinafter referred to as a reservoir unit) 4 capable of selectively introducing the cleaning liquid 4c,
It has a sample holder 5 capable of sequentially loading one measurement target sample Sm from a plurality of measurement target samples S _{1 to} Sn. In addition, the measurement unit 2 mixes the measurement target sample Sm with the dispersion media 4a and 4b to generate the sample liquid S.
A pump 7 for circulating the sample solution S, a cell 8 in which the sample solution S is flown, a solenoid valve 9 for draining the sample solution S, and a particle mass for each particle contained in the sample solution S. Ultrasonic generator 10 for preventing the generation of noise
And form a circulation system 11.

Reference numeral 12 is a laser light source for irradiating the cell 8 with laser light, and 13 is a detector 13 for measuring the intensities of the transmitted light Lt and scattered light Ls of the laser light from the laser light source 12, and a plurality of detectors 13 are provided. It is composed of detectors 13a to 13n. Then, the laser light source 12 and the detector 13
Form an optical system 14. In addition, 15 is each detector 1
It is a measurement unit that calculates the particle size distribution of the measurement target sample Sm using the outputs from 3a to 13n.

By connecting 16 to the solenoid valve 9,
A waste liquid flow path for discharging the sample liquid S, which has been circulated in the circulation system 11 and whose particle size distribution has been measured, as waste liquid,
Reference numeral 17 denotes a waste liquid processing section provided in the waste liquid flow path 16 for separating the waste liquid into the dispersion media 4a and 4b and the sample Sm to be measured.

Reference numeral 18 denotes a sample-to-be-measured sample recovery section which constitutes the waste liquid processing section 17, and 19 denotes a dispersion medium recovery section. The sample-to-be-measured sample recovery section 18 uses a filter 20 to capture only the sample-to-be-measured Sm. The dispersion medium collection unit 19 collects the dispersion mediums 4a and 4b that have passed through the measurement target sample collection unit 18.

The measuring unit 15 communicates with the personal computer 3 and outputs control signals to the above-mentioned respective units 4 to 19 to obtain the particle size distributions of a plurality of samples S _{1 to} Sn to be measured. Is configured as follows.

FIG. 2 is an enlarged view showing the structure of the main part of the sample collection part 18 to be measured. The example shown in FIG. 2 illustrates an example of the sample collection unit 18 to be measured, but does not limit the present invention.

As shown in FIG. 2, the waste liquid flow path 16 is divided at appropriate places, one pipe body 16a is fixed in position, and the other pipe body 16b is provided with the actuator 16.
It is configured to be slidable up and down by c. That is, the waste liquid flow path 16 is moved to the filter 20 by the rising of the pipe body 16b.
The filter 20 is opened from the waste liquid flow path 16 as the pipe 16b descends.

Reference numeral 18b is a table that is rotated by a motor 18a (see FIG. 1) of the sample collection unit 18 to be measured, and has a hole 18c on which a plurality of filters 20 can be set. Further, a taper 18 for determining the position of the filter 20 is provided on the outer periphery of the upper surface of the hole 18c.
forming d. That is, the actuator 16c
Installation and opening of the filter 20 by the table 18
By combining rotations of b, different filters 20 are sequentially replaced in the waste liquid flow path 16 to form an automatic filter replacement mechanism that enables setting.

The above-described automatic filter changing mechanism allows a plurality of filters 20 to be set on the rotating table 18b in order to collect a plurality of samples to be measured separately. It may slide. In any case, by collecting multiple measurement target samples separately, it is possible to collect multiple measurement target samples without mixing each measurement target sample when they are continuously measured. Available.

The filter 20 has a flange 20a having an outer periphery which is caught in the hole 18c, and the flange 20a.
Conical permeable membrane part 20 made of a filter material having a finer mesh size than the particle size of any measurement target sample
b, and is configured so that the sample Sm to be measured can be separated from the sample liquid S by the permeable membrane portion 20b. It goes without saying that the configuration of the filter 20 is not limited to that shown in this example.

The mesh of the permeable membrane portion 20b can improve the flow of waste liquid by using a mesh if the sample to be measured has a size of about 1 mm.
When the sample to be measured to be handled is of the micron order, a disposable membrane can be used. Further, in order to improve the flow, the surface area of the filter 20 should be increased by increasing the size of the filter 20 or forming a large number of irregularities on the permeable membrane 20b.
It is conceivable to use a plurality of filters in order of coarse particles.

The particle size distribution measuring apparatus 1 according to the present invention comprises a filter 2
Since the sample liquid S discharged by using 0 is separated into the sample to be measured and the dispersion medium, and the sample to be measured is reliably captured,
If the dispersion medium is a harmless aqueous solution, it can be discharged as it is. Further, when a valuable sample to be measured is measured, it can be collected by removing the filter 20.

If the sample to be measured is sufficiently removed from the dispersion medium separated by the filter 20, it can be reused. That is, the dispersion medium can be collected in the tank 19a as shown in FIG. 1 and returned to the reservoir unit 4 by the pump 19b. If the dispersion medium does not need to be reused, the valve 1
The dispersion medium can be discharged as it is by opening 9c.

In order to simplify the drawing, the drawing shown in FIG. 1 shows an example in which only the dispersion medium 4a is reused, and the structure for reusing the other dispersion medium 4b is omitted.
Further, various modifications are possible, such as providing a switching valve at the downstream end of the waste liquid flow path 16 for switching between collecting in the tank 19a and discharging as it is.

FIG. 3 is a flow chart showing an example of processing by the control program P executed by the personal computer 3 when the particle size distributions of a plurality of measurement target samples S _{1 to} Sn are sequentially measured. The processing contents shown in FIG. 3 will be described below with reference to FIGS. 1 and 2.

In FIG. 3, S1 is a mixing unit 6 that uses, for example, an organic solvent (hereinafter, simply referred to as solvent 4a) as a dispersion medium 4a for particle size distribution measurement using the reservoir unit 4.
It is the step of injecting into the inside. That is, the reservoir unit 4 that has received the command from the personal computer 3 has a solenoid valve 4d for taking out the solvent 4a (the reservoir unit 4 also has solenoid valves 4e, 4 for taking out the dispersion medium 4b and the cleaning liquid 4c).
the solvent 4a is injected into the mixing section 6 by driving the pump 4g and the float 4
Water is supplied until h reaches a predetermined height. Reference numeral 4i is a controller that controls the solenoid valves 4d to 4f and the pump 4g by checking the water level from the position of the floating ball 4h.

In S2, the injected solvent 4a is added to the centrifugal pump 7
The solvent 4a is agitated with a solvent such as
It is a step of circulating in 1. By this step S1, the solvent 4a is filled in the circulation system 11, and the bubbles mixed in the circulation system 11 can be removed.

S3 is a step of performing a blank measurement using the injected solvent 4a. The intensities of the transmitted light Lt and each scattered light Ls obtained in this blank measurement are used in the calculation of the particle size distribution and so on, and are stored in the personal computer 3.

S4 is a step of sequentially introducing the measurement target sample Sm from the measurement target samples S _{1 to} Sn into the mixing section 6 using the sample holder 5. The sample holder 5
For example, 24 cups 5a respectively accommodating the measurement target samples S _{1 to} Sn rotate around a rotation shaft 5b, and the measurement target samples S _{1 to} Sn are sequentially instructed by a personal computer 3 (processing unit). It is configured to be charged into the mixing section 6.

S 5 is a step in which the sample Sm to be measured is mixed with the solvent 4 a and stirred to form the sample solution S, and the sample solution S is circulated in the circulation system 11. That is, according to an instruction from the personal computer 3, the pump 7 is driven to mix the sample Sm to be measured with the solvent 4a, and the sample Sm can be circulated in the circulation system 11 while being stirred.

Further, in the particle size distribution measuring apparatus 1 of this example, the ultrasonic wave transmitter 10 is driven to prevent the formation of the lump of the sample Sm to be measured, and to circulate the sample liquid in the circulation system 11. S is configured to be sufficiently dispersed and kept in a stirred state.

S6 is a step of measuring the particle size distribution of the sample liquid S circulating in the circulation system 11. That is, when the sufficiently stirred sample liquid S circulates in the circulation system 11, laser light is emitted from the laser light source 12 to the cell 8 in accordance with a command from the personal computer 3, and the transmitted light L generated at that time is generated.
t and the intensity of each scattered light Ls are detected by the detectors 13a to 13n.
Detect by. The outputs of the detectors 13a to 13n are loaded into the personal computer 3 and analyzed to obtain the particle size distribution of the measurement target sample Sm. That is, these steps S1 to S6 indicate the measurement procedure of the measurement target component.

S7 is a filter 2 which is different for each sample to be measured.
This is a step for setting 0. In other words, the measurement unit 15 has the measurement target sample collection unit 18 before opening the solenoid valve 9.
Control is performed to set one filter 20 in the waste liquid flow path 16 as already described with reference to FIG. (Thereafter, different filters 20 are set each time this step S7 is executed.)

S8 is a step of draining the measured sample liquid S. At this time, almost all of the measurement target sample Sm is discharged, so that most of the measurement target sample Sm used for the measurement is captured by the filter 20. However, some measurement target sample Sm is left in the circulation system 11.

Step S9 is a step of injecting the solvent 4a for cleaning the circulation system 11 into the mixing section 6 using the reservoir unit 4 and the like.

S10 is the solvent 4 using the centrifugal pump 7 or the like.
a step of stirring and cleaning the circulation system 11 by stirring a and circulating the circulation system 11;
The same dispersion medium 4a used for measuring the particle size distribution of the measurement target sample Sm is circulated in the circulation system 11 to be washed with stirring.

S11 is a blank measurement performed using the solvent 4a after washing with stirring. At this time, when almost no sample Sm to be measured remains in the circulation system 11, the transmitted light Lt having almost the same transmittance as the blank measurement in step S3 is obtained, and the scattered light Ls that is almost 0 is detected. . However, when the measurement target sample Sm remains in the circulation system 11, the transmitted light Lt becomes weak and the scattered light Ls becomes strong. Therefore, the personal computer 3 records the result of the blank measurement in step S11.

S12 is a step of draining the washed solvent 4a. That is, the measurement target sample Sm dropped from the circulation system 11 in the stirring and washing step S8 is discharged and also captured by the filter 20.

Step S13 is a step of judging the degree of fouling of the circulation system 11 based on the measurement value of step S11. In the case of the present example, for example, the degree of contamination is judged by the measured value of the transmitted light Lt being 99% or more of the value at the time of the blank measurement in step S3. If the measured value of the transmitted light Lt does not reach 99%, it is determined that the degree of contamination is large (that is, a large amount of the sample Sm to be measured remains in the circulation system 11) and the process is repeated from step S9. The cleaning operation is repeated.

The circulation system 1 is used to judge the degree of contamination of the circulation system 11.
By judging by the measured value of the transmitted light Lt in the blank measurement after the circulation cleaning of No. 1, it is possible to judge the contamination in the entire circulation system 11 and whether the next particle size distribution measurement can be performed. Can be reliably determined. In addition, although the description is omitted in this example, the scattered light L
It is possible to accurately determine the degree of contamination of the circulation system 11 based on the measured values of s and reflected light.

Cleaning operations S9 to S1 for carrying out the circulation cleaning.
2 is repeatedly performed according to the cleaning state of the circulation system 11 until the measurement target sample Sm in the circulation system 11 is sufficiently exhausted. Therefore, when the measurement target sample Sm hardly remains in the circulation system 11 during drainage, one cleaning is performed. While the operations S8 to S12 may be sufficient, in the case of the adhesive measurement target sample Sm, it may be necessary to perform the operations a plurality of times in succession. In any case, since a small amount of the measurement target sample Sm left in the circulation system 11 is captured in the minimum required time, the filter 20 captures all the measurement target sample Sm input from the cup 5a. It

[0043] S14, a step of particle size distribution measurement of all the sample to be measured S ₁ to Sn to determine whether the termination, the if there are still measured sample S ₁ to Sn unmeasured yet By returning the processing to step S1,
You can move to the next measurement. That is, by performing the series of processes shown in FIG. 3, the particle size distribution measuring device 1 fully automatically measures the particle size distributions of the plurality of measurement target samples S _{1 to} Sn even without an operator. The measurement result can be stored in the personal computer 3 and the measured measurement target sample Sm can be collected by using the filter 20.

Therefore, the valuable sample to be measured should be kept as it is.
It is automatically collected without being discarded and wasted.
This can be used repeatedly. Also, the test target
If the material Sm is an environmental pollutant, it must be collected.
Appropriate disposal can be performed by and. In addition, the book
As shown in the example, each filter 20 has a sample S to be measured. ₁
When recovering Sn, each filter 20
Collected measurement target sample S₁~ Sn again in cup 5a
Change the temperature condition, pH, type of dispersion medium, etc.
It is also possible to measure repeatedly. That is, the measurement pair
Elephant sample S₁~ Sn is involved in trade secrets such as newly developed chemicals
If it is a compound such as
Fee S₁~ It is possible to conduct research and development by repeatedly using Sn.
Not only can it be used, but it can also be useful for maintaining confidentiality.

Further, if the sample to be measured is sufficiently removed, the dispersion medium can be reused. Therefore, when an organic solvent or the like is used as the dispersion medium as in this example, the reuse can save the cost. By reducing the waste liquid,
The load on the environment is greatly reduced.

[0046]

In the particle size distribution measuring apparatus of the present invention, the dispersion medium and the sample to be measured can be separated by the waste liquid treatment section provided in the flow path for flowing the sample liquid as the waste liquid, so that the separated dispersion medium is stored. By preserving it, the dispersion medium can be recovered very easily, and the cost for measuring the particle size distribution can be suppressed. In particular, in the case of a dispersion medium that may adversely affect the environment such as an organic solvent, minimizing its use can contribute to environmental protection.

Similarly, the separated sample to be measured can be easily recovered, which can contribute to cost reduction especially in the case of a valuable sample to be measured. Further, when the sample to be measured is a compound such as a newly developed drug which is related to trade secrets, the confidentiality can be kept by surely collecting it. In addition, when the sample to be measured is an environmental pollutant, it is possible to contribute to environmental protection by reliably collecting it. Further, the same sample to be measured can be dispersed in different dispersion media for measurement, or can be repeatedly analyzed under various different conditions such as different temperatures and pHs.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a particle size distribution measuring device of the present invention.

FIG. 2 is an enlarged view showing a configuration of a main part of the particle size distribution measuring device.

FIG. 3 is a diagram showing a flow of processing by a control program for analyzing a plurality of measurement target samples by using the particle size distribution measuring device of the present invention.

[Explanation of symbols]

1 ... a particle size distribution measuring apparatus, 4a, 4b ... dispersion medium, 16 ... disposal passage, 17 ... waste liquid treatment unit, 18 ... measurement target sample recovery unit, 19 ... dispersion medium recovery unit, S ... sample liquid, S ₁ ~ S
n, Sm ... Sample to be measured.

Claims (4)

[Claims] 1. Particles of a sample to be measured by mixing and stirring a sample to be measured in a dispersion medium to generate a sample liquid, and measuring the intensity of transmitted light and scattered light generated when the sample liquid is irradiated with light. A particle size distribution measuring device for measuring a particle size distribution, characterized in that a waste liquid processing unit for separating a dispersion medium and a sample to be measured is provided in a channel for discharging a sample liquid after measurement. . 2. The particle size distribution measuring device according to claim 1, wherein the waste liquid processing unit has a dispersion medium recovery unit that recovers the separated dispersion medium and makes it reusable. 3. The particle size distribution measuring device according to claim 1, wherein the waste liquid processing unit has a measurement target sample recovery unit that recovers the separated measurement target sample. 4. The particle size distribution measuring device according to claim 1, wherein the waste liquid processing unit has a filter having a finer mesh than the sample to be measured in order to separate the sample to be measured from the dispersion medium. .