JP2004069512A - Particle size distribution measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a particle size distribution measurement device capable of efficiently draining waste liquid after use in a measurement circulation system and minimizing a preparation time between one measurement and the following measurement for efficiently performing desired measurement in a short time when a plurality of measurement processes are sequentially carried out. <P>SOLUTION: In this particle size distribution measurement device having a measurement circulation system 19 connecting a dispersion bath 2 for dispersing a sample 6 in a dispersion medium 9, a flow cell 16, and a circulation pump 17 via a circulation passage 18, a waste liquid storage tank 22 is connected to the measurement circulation system 19 via a switch valve 20. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a particle size distribution measuring device.
[0002]
2. Description of the Related Art As one of particle size distribution measuring devices, a measurement circulation system in which a dispersion bath for dispersing a sample in a dispersion medium and forming a sample liquid, a flow cell, and a circulation pump are connected through a circulation channel. In some cases, a laser beam is irradiated to the flow cell in a state where the sample liquid is supplied to the flow cell, and the particle size distribution is measured by utilizing a diffraction or scattering phenomenon of light caused by particles in the sample liquid.
In the above particle size distribution measuring device, when the measurement of a certain sample is completed, an on-off valve attached to the measurement circulation system is opened to drain the sample liquid, and then the on-off valve is closed to close the measurement circulation system. Is washed with a washing liquid, the opening and closing valve is opened again, and the washed liquid is drained to prepare for the next sample measurement.
[0004]
[Problems to be solved by the invention]
However, in the conventional particle size distribution measuring device, when the sample water existing in the measurement circulation system or the washing water after washing is discharged from the measurement circulation system as a waste liquid after the measurement is completed, a so-called spontaneous discharge takes a form. In this case, if the end of the drain hose is immersed in the drain in the drain outside the device, or if the hose is long, it takes time to discharge the waste liquid. It takes a long time to perform the measurement, and particularly when a large number of samples are measured, it is not possible to efficiently perform a desired measurement in a short time.
The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to make it possible to efficiently drain waste liquid after measurement in a measurement circulation system and to perform a plurality of measurements continuously. In such a case, it is possible to provide a particle size distribution measuring device capable of performing a desired measurement efficiently in a short time by minimizing a preparation time between one measurement and a subsequent measurement. It is.
[0006]
In order to achieve the above object, the present invention provides a measuring circulating system in which a dispersion bath for dispersing a sample in a dispersion medium, a flow cell, and a circulating pump are connected via a circulating flow path. In the particle size distribution measuring device provided, a waste liquid storage tank is connected to the measurement circulation system via an on-off valve.
In the above particle size distribution measuring device, when one measurement is completed, an opening / closing valve between the measurement circulation system and the waste liquid storage tank is opened, and the sample liquid after measurement present in the measurement circulation system is drained. Discharge to storage tank. After discharging the sample liquid, the on-off valve is closed, the inside of the measurement circulating system is washed with the cleaning liquid, and the liquid used for the cleaning is discharged to the waste liquid storage tank via the on-off valve. Thereafter, the on-off valve is closed and the process waits for the next measurement. By doing so, the waste liquid after the measurement can be drained from the measurement circulation system in a short time as compared with the related art, so that the waiting time until the next measurement is reduced, and a plurality of measurements are continuously performed. In this case, a desired measurement can be efficiently performed in a short time. Then, the waste liquid discharged to the waste liquid storage tank may be appropriately discharged to the drainage channel until the next measurement is completed.
[0008]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. 1 and 2 show one embodiment of the present invention. First, FIG. 1 schematically shows an example of the configuration of a particle size distribution measuring apparatus according to the present invention. In this figure, reference numeral 1 denotes a measuring apparatus main body, which is configured as follows. That is, reference numeral 2 denotes a dispersion bath, in which a stirring blade 4 rotated by a motor 3 is provided, and an ultrasonic vibrator 5 oscillated by an oscillator is provided outside the bottom thereof. A sample liquid (also referred to as a suspension) 10 is prepared by adjusting particles (for example, powder or granules) 6 as a sample and a dispersion medium 9 supplied from a dispersion medium tank 7 through a dispersion medium supply pipe 8. It is assumed that. Reference numeral 11 denotes an opening / closing valve such as a normally closed solenoid valve provided in the dispersion medium supply pipe 8. Reference numeral 12 denotes a cleaning liquid tank for storing the cleaning liquid 13, which supplies the cleaning liquid 13 to the dispersion bath 2 through a cleaning liquid supply pipe 15 having an on-off valve 14 such as a normally closed solenoid valve.
[0009]
Reference numeral 16 denotes a flow cell as a sample cell, which is connected to the dispersion bath 2 by a circulation flow path 18 provided with a circulation pump 17, and forms a measurement circulation system 19 together with these members 2, 17, and 18. A drain pipe 21 is connected between the flow cell 16 of the measurement circulation system 19 and the circulation pump 17 via an on-off valve 20 such as a normally closed solenoid valve. The waste liquid storage tank 22 is connected to the side. In this case, it is preferable that the drain pipe 21 is considerably thicker than the pipe constituting the circulation channel 18 and is as short as possible.
The waste liquid storage tank 22 is provided, for example, in the measuring device main body 1 and includes an air vent pipe 22a, and at the bottom thereof, an open / close valve 23 such as a normally closed solenoid valve and a discharge pump 24. The drainage channel 25 is connected. The downstream side of the drainage channel 25 is connected to a drainage channel (not shown) outside the apparatus. The content of the waste liquid storage tank 22 is larger than the total amount of the sample liquid 10 used for one measurement and the total amount of the cleaning liquid 13 used for cleaning the measurement circulation system 19 after the measurement. For example, it is set to a level that can accommodate about five times the liquid (waste liquid).
Reference numeral 26 denotes a laser light source provided on one side of the flow cell 16, reference numerals 27 and 28 denote condensing lenses and photodetectors provided on the other side of the flow cell 16, and the photodetector 27 comprises, for example, a plurality of detectors. Are arranged in a ring shape, and convert the incident scattered light into an electric signal.
Reference numeral 29 denotes a signal switching circuit such as a multiplexer for sequentially switching and outputting the electric signal from the photodetector 28, and reference numeral 30 denotes an AD converter for converting the electric signal into a digital value.
An arithmetic control unit 31 controls various parts of the measuring apparatus main body 1 and performs various calculations, and is a computer such as a personal computer, for example. The computer 31 includes a CPU 32, a ROM 33, a RAM 34, an input device 35 such as a keyboard, a display operation device 36, a printer (not shown), and the like.
In the ROM 33, in addition to various control programs, a program for calculating a particle size distribution operation constant using parameters input to the sample and the dispersion medium, and a particle size distribution operation constant file are stored. And a program for obtaining the particle size distribution. The RAM 34 stores the results of the arithmetic processing by the CPU 32 and the information input by the input device 35, as well as various parameters and particle size distribution calculation constant files. Further, the display operation device 36 is configured to display processing results of the CPU 32, data stored in the RAM 34, and various types of input information, and to input control information and the like on the screen in an interactive manner.
Next, the operation of the particle size distribution measuring device having the above configuration will be described with reference to FIG. First, the function key “inject” (not shown) on the screen of the display / operation device 36 of the computer 31 is operated. As a result, the on-off valve 11 is opened, and an appropriate amount of the dispersion medium 9 is introduced into the dispersion bath 2 (Step S1).
Then, the function key "circulation" (not shown) on the screen is operated. As a result, the agitating and circulating pump 17 operates, the dispersion medium 9 circulates in the measurement circulation system 19 along the circulation flow path 18, and the flow cell 16 is filled with the dispersion medium 9 (step S2).
Next, the function key "blank" (not shown) on the screen is operated. Thus, the laser light is emitted from the laser light source 26 to the flow cell 16 filled with the circulating dispersion medium 9, and the amount of scattered (diffraction) light is measured (blank measurement) without particles. The data at this time is stored in the CPU 32 (step S3).
After the blank measurement, an appropriate amount of the sample 6 is put into the dispersion bath 2 (step S4).
The function key "Agitate" (not shown) on the screen is operated. As a result, the motor 3 operates, the stirring blade 4 rotates, and the dispersion medium 7 containing the sample 6 is stirred. Along with this operation, the function key "ultrasonic" (not shown) on the screen is operated. As a result, the ultrasonic vibrator 5 operates to perform an ultrasonic dispersion process so that the sample 6 is uniformly dispersed in the dispersion medium 9, and a predetermined sample liquid 10 is obtained (Step S5). Then, at the same time as the start of the ultrasonic dispersion processing, the function key “circulation” is operated. Thereby, the circulation pump 17 operates, and the sample liquid 10 circulates in the measurement circulation system 19. By irradiating the flow cell 16 with a laser beam in this state (step S6), the main measurement using the sample liquid 10 is performed.
The scattered light generated by the irradiation of the laser light is taken into the photodetector 28 (step S6).
Then, a signal corresponding to the intensity of the scattered light is output from the photodetector 28, and this signal is input to the CPU 32 via the signal switching circuit 29 and the AD converter 30. The CPU 32 performs the particle size distribution calculation in consideration of the data at the time of the blank measurement (step S7).
Then, the result of the particle size distribution calculation is displayed on the display screen of the display operation device 36 as a particle size distribution graph (step S8).
After performing the desired measurement, the on-off valve 20 is opened by operating the function key "Drain" (not shown) on the screen (step S9), and the sample in the measurement circulation system 19 is opened. All the liquid 10 is discharged (step S10), and stored in the waste liquid storage tank 22 via the drain pipe 21. In this case, the drain pipe 21 is made as thick and as short as possible as compared with the circulation flow path 18 in the measurement circulation system 19 and the waste liquid storage tank 22 is provided with an air vent pipe 22a. 10 is discharged from the measurement circulation system 19 at once (quickly).
Then, by operating the function key "wash" (not shown) on the screen, the on-off valve 20 is closed (step S11) and the on-off valve 14 is opened. When the on-off valve 14 is opened, the cleaning liquid 13 is supplied from the cleaning liquid tank 12 to the measurement circulation system 19 via the dispersion bath 2 and circulated, whereby all parts in the measurement circulation system 19 are cleaned. (Step S12).
When the cleaning is completed, the on-off valve 14 is closed and the on-off valve 20 is opened (step S13), and the cleaning liquid 13 in the measurement circulation system 19 is entirely discharged (step S14). The waste liquid is stored in the waste liquid storage tank 22. The discharge of the cleaning liquid 13 from the measurement circulation system 19 is promptly performed for the same reason as the discharge of the sample liquid 10. Thereafter, the on-off valve 20 is closed (step S15), and a standby state for the next measurement is established.
The waste liquid such as the sample liquid 10 and the cleaning liquid 13 discharged into the waste liquid storage tank 22 after the measurement is temporarily stored in the waste liquid storage tank 22, and this waste liquid is used for the next measurement. Even if the liquid is slowly discharged from the waste liquid storage tank 22 to the drain (not shown) outside the apparatus through the drain 25 during this time, the next measurement is not hindered at all. Then, the sample liquid 10 is newly supplied to the washed measurement circulating system 19 and circulated to perform the blank measurement or the main measurement.
As described above, in the particle size distribution measuring apparatus according to the above embodiment, when one measurement is completed, the sample liquid 10 used for the measurement, the cleaning liquid 13 used for cleaning the measurement circulation system 19, etc. Is discharged directly into a waste liquid storage tank 22 provided in the apparatus, instead of being discharged directly to a drainage channel outside the apparatus, as in the prior art. Is set to the standby state for the next measurement in as short a time as possible, so that when performing multiple measurements in succession, the preparation time between measurements can be reduced, and multiple measurements can be performed. Is performed continuously, desired measurement can be performed efficiently in a short time.
In the particle size distribution measuring device described above, the drainage pipe 21 connecting the measurement circulation system 19 and the waste liquid storage tank 22 is thicker and wider than the circulation flow path 18 of the measurement circulation system 19. The waste liquid in the measurement circulating system 19 can be discharged at a stretch because the waste liquid storage tank 22 is provided with an air vent pipe 22a. The displacement of the air with the liquid is quickly performed, and the waste liquid is discharged from the measurement circulation system 19 very quickly.
The waste liquid temporarily stored in the waste liquid storage tank 22 is discharged to a drain outside the apparatus by opening an on-off valve 23 provided in a drain flow path 25 and operating a discharge pump 24. You. Note that the on-off valve 23 and the discharge pump 24 are not necessarily provided. Further, instead of the discharge pump 24, air may be pressure-fed to the waste liquid storage tank 22 to quickly discharge the waste liquid therein.
The particle size distribution measuring apparatus in the above embodiment irradiates the flow cell 16 with laser light, and utilizes the light diffraction or scattering phenomenon of the particles in the sample solution 10 in the flow cell 16 to reduce the particle size. Although the present invention is configured as a so-called static light scattering type particle size distribution measuring device for performing a diameter distribution measurement, the present invention is not limited to this, and a dispersion bath 10 for dispersing a sample 6 in a dispersion medium 9 and a flow cell 16 The same can be applied to a particle size distribution measuring device provided with a measurement circulation system 19 in which a measurement circulation system 19 is connected to a circulation pump 17 via a circulation flow path 18. Therefore, if the apparatus has the measurement circulation system 19, the particles scattered in the dispersion medium and perform the Brownian motion are irradiated with light, and the interference light generated by the Doppler shift of the scattered light by the particles is electrically detected. The present invention can be similarly applied to a dynamic light scattering type particle size distribution measuring device which converts the detection signal into a signal and calculates the particle size distribution by subjecting the detected signal to appropriate arithmetic processing.
[0031]
As described above, according to the particle size distribution measuring apparatus of the present invention, it is possible to efficiently drain the waste liquid such as the sample liquid and the cleaning liquid after the measurement in the measurement circulating system, and to perform the plural measurement. Is performed continuously, the preparation time between one measurement and the next measurement can be reduced as much as possible, and desired measurement can be performed efficiently in a short time. Therefore, many samples can be measured efficiently in a short time.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an example of the configuration of a particle size distribution measuring device of the present invention.
FIG. 2 is a flowchart for explaining the operation of the particle size distribution measuring device.
[Description of Signs] 2 ... Dispersion bath, 6 ... Sample, 9 ... Dispersion medium, 16 ... Flow cell, 17 ... Circulation pump, 19 ... Measurement circulation system, 20 ... On-off valve, 22 ... Waste liquid storage tank.

Claims (1)

In a particle size distribution measuring apparatus having a measurement circulation system in which a dispersion bath for dispersing a sample in a dispersion medium, a flow cell, and a circulation pump are connected through a circulation flow path, a waste liquid is supplied to the measurement circulation system through an on-off valve. A particle size distribution measuring device characterized by connecting a storage tank.

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