JPH09145590A - Measuring apparatus for dry particle-size-distribution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a measuring apparatus for dry particle-size-distribution by which nearly the total amount of a used sample, to be measured, can be collected simply and surely without being contaminated with other sample or the like. SOLUTION: In the measuring apparatus, a powdery sample S which is dispersed by a disperser 1 is made to flow into a measuring cell 5, a beam of light is made incident on the measuring cell 5 so as to be transmitted, and a particle-size distribution is measured on the basis of detection data on the scattered light and the transmitted light of the sample S. At this time, the disperser 1 is constituted in such a way that a stirring wing 3 which is turned and driven by a motor 4 is installed inside a container 2 in which the sample S is housed. In addition, the upstream side and the downstream side of the measuring cell 5 are connected to the container 2 at the disperser 1 via a forward pipe 8 and a backward pipe 10, and an airtight circulating route 11 is constituted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry particle size distribution measuring device for measuring a particle size distribution of a sample by flowing a measuring sample composed of powdery or granular particles or a mixture thereof into a measuring cell.

[0002]

2. Description of the Related Art In recent years, measurement of dry particle size distribution has become automatic. FIG. 3 schematically shows a main part of a conventional example of such a dry particle size distribution measuring apparatus. This apparatus quantitatively supplies a measurement sample S from a sample supply device 33 to the orifice 31 of an ejector-type disperser 32 in which an orifice 31 is inserted into a sample supply cylinder 30 to which compressed air ca is supplied. The measurement sample S dispersed by the disperser 32 is caused to flow into the measurement cell 35 of the measurement optical section 34, and the measurement sample S that has passed through the measurement cell 35 is collected in the suction device 37 via the tube 36.

[0003]

However, in the above-mentioned conventional example, since the measurement sample S that has once passed through the measurement cell 35 is collected by the aspirator 37 via the tube 36, the collected sample is reused for measurement, for example. In order to do so, the collection bag of the aspirator 37 must be replaced for each sample,
The work is complicated. Further, since the previous measurement sample S is attached to the tube 36 and the like, when the measurement sample S is different from the previous time, the measurement sample S collected by the suction device 37 is contaminated and cannot be reused.

The present invention has been made in view of the above matters, and an object thereof is to easily and surely recover almost all of the used measurement sample without being contaminated by other samples. A distribution measuring device is provided.

[0005]

In order to achieve the above object, according to the present invention, a powdery or granular sample dispersed by a disperser is made to flow into a measuring cell, and a light beam is made incident on the measuring cell and transmitted therethrough. The dry type particle size distribution measuring device for measuring the particle size distribution of the sample based on the detection data of the scattered light and / or the transmitted light of the sample has the following configuration. That is, the disperser is configured such that a stirring blade that is rotationally driven by a motor is provided in a container that stores a sample, and the upstream side and the downstream side of the measurement cell are connected to the disperser via a forward path tube and a return path tube. To form a closed circulation path.

In the dry particle size distribution measuring apparatus of the present invention, the sample contained in the container of the disperser is dispersed by the rotation of the stirring blade, and the dispersed sample is dispersed by the air flow created by the stirring blade.
Since it circulates in the closed circulation path that returns to the container of the disperser through the outward tube, the measurement cell, and the return tube, it is contaminated by other samples by exchanging the circulation path for each sample to be measured. Without, almost all of the used sample can be collected easily and reliably.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a dry particle size distribution measuring device of the present invention. Reference numeral 1 denotes an impactor-type disperser, in which a stirring blade 3 for dispersing the measurement sample S is installed in a container 2 containing a powdery measurement sample S, and the stirring blade 3 is rotationally driven by a motor 4 outside the container 2. Is configured to. The container 2 of the impactor type disperser 1 has a bottom portion which is openably and closably closed by a bottom lid 2a as shown in FIG. 2, and a stirring blade 3 is provided on the bottom lid 2a. Motor 4 for this stirring blade 3
Are detachably connected.

Reference numeral 5 is a measurement cell (hereinafter referred to as a flow cell)
In the optical chamber 6 that constitutes the measurement optical section, the optical chamber 6 is arranged vertically. The upstream side of the flow cell 5 is connected to the upper portion of the container 2 of the impactor type disperser 1 by an outward pipe 8 with a valve 7 interposed therebetween.
The downstream side of the flow cell 5 is connected to the lower portion of the container 2 by a return pipe 10 with a valve 9 interposed in the middle. That is, the container 2, the outward tube 8, the flow cell 5, and the return tube 10 constitute a closed circulation unit 11 for the measurement sample S. The circulation path unit 11 has a simple structure as described above, and can be easily removed from the optical chamber 6 as it is and replaced with another circulation path unit 11. Reference numerals 12a and 12b are windows of the flow cell 5.

In the optical chamber 6, He--Ne is contained.
A laser 13 is provided and its laser light is reflected by a reflection mirror 14.
It is configured such that the light enters the flow cell 5 via the beam expander 15 arranged opposite to the window 12a via a and 14b and is transmitted therethrough. Reference numeral 16 denotes a magnifying lens provided so as to face the window 12b.

Reference numeral 17 denotes a photodetector which detects the light which has passed through the flow cell 5 and passed through the window 12b. For example, photodiodes are arranged in a ring shape. The transmitted light data detected by this photodetector 17 is sent to the multiplexer 18 and A /
It is configured to be selected by the CPU 20 via the D converter 19 and to input only the selected transmitted light data to the control device 21. The control device 21 is provided with a display unit 22 that displays the particle size distribution measured based on the input detection data. The control device 21 also controls the mechanical parts such as the opening and closing of the valves 7 and 9 and the driving of the motor 4 in addition to the calculation processing of the particle size distribution.

Reference numeral 23 is a photodetector composed of a plurality of photodiodes, which are windows 12a and 12b for individually detecting scattered light having different scattering angles, which is generated when the measurement sample S flowing in the flow cell 5 is irradiated with the laser light. It is located relative to. The scattered light data detected by each of the photodetectors 23 is also input to the control device 21 in the same manner as the transmitted light data.

Next, the operation of the dry particle size distribution measuring apparatus having the above-mentioned structure will be described according to the operation procedure. (1) First, the bottom cover 2a of the container 2 of the impactor type disperser 1 is opened and the measurement sample S in the form of powder is contained inside the container 2. (2) Next, with the valves 7 and 9 closed, the stirring blade 3 of the impactor-type disperser 1 is set to 10,000 to 30,000 rp.
Rotate at a rotation speed of m for over ten seconds to several minutes.
Thereby, the dispersion process of the measurement sample S can be performed without lowering the dispersion efficiency as compared with the case of the ejector type disperser. (3) Valves 7 and 9 while continuing to rotate the stirring blade 3
open. Thereby, the container 2 of the impactor type disperser 1
The measurement sample S filling the inside flows from the outward pipe 8 to the flow cell 5 by the air flow created by the stirring blade 3, and the return pipe 1
The circulation of returning from 0 to the container 2 of the impactor type dispersing device 1 again is repeated. (4) At this time, the measurement sample S flowing in the flow cell 5
Traverses the laser light from the He-Ne laser 13. The scattered light at this time is detected by the photodetectors 17 and 23. The detection outputs of these photodetectors 17 and 23 are input to the control device 21, and the particle size distribution is calculated and displayed based on the data. (5) When the measurement is completed, the rotation of the stirring blade 3 of the impactor type disperser 1 is stopped, the entire circulation path unit 11 is removed from the optical chamber 6, and the measurement sample S in this circulation path unit 11 is collected. After the collection, the circulation path unit 11 is washed and used for measurement of another measurement sample S.
In addition, when another measurement sample S is to be measured immediately after the measurement, another circulation path unit 11 containing the measurement sample S in the container 2 of the impactor type disperser 1 is provided in the optical chamber 6. This can be done by mounting.

In the dry particle size distribution measuring apparatus, since the measurement sample S is circulated in the closed circulation path unit 11,
After the measurement, almost the entire amount of the measurement sample S can be recovered without being contaminated with other substances. In addition, even with a measurement sample that reacts when mixed with another substance or a toxic measurement sample, the particle size distribution can be measured safely by the dry measurement method without any problem. Also, since the measurement sample is circulated and measured,
Even a small amount of measurement sample can be measured.

[0014]

As described above, according to the present invention, the dispersing device is constructed by providing a stirring blade, which is rotationally driven by a motor, in the container for containing the sample, and the upstream side and the downstream side of the measuring cell are arranged. By connecting to the container of the disperser through the forward pipe and the return pipe, a closed circulation path is formed, so that the sample dispersed by the disperser can be circulated in the circulation path for measurement. By exchanging the circulation path for each sample to be measured, almost all of the used sample can be collected easily and reliably without being contaminated by other samples.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an example of a dry particle size distribution measuring device of the present invention.

FIG. 2 is an explanatory view of an opening operation of a container bottom lid of the impactor type dispersion device in the apparatus.

FIG. 3 is a diagram showing a conventional example.

[Explanation of symbols]

1 ... Impactor type disperser, 2 ... Container, 3 ... Stirrer, 4
... Motor, 5 ... Measuring cell (flow cell), 8 ... Forward tube,
10 ... Return pipe, 11 ... Circulation path unit, S ... Measurement sample

Claims (1)

[Claims] 1. A powder-granular sample dispersed by a disperser is caused to flow into a measurement cell, and a light beam is made incident on the measurement cell to be transmitted, and based on detection data of scattered light and / or transmitted light of the sample. In a dry particle size distribution measuring apparatus for measuring the particle size distribution of a sample, the disperser is provided with a stirring blade that is rotationally driven by a motor in a container that contains the sample, and the upstream side and the downstream side of the measurement cell are A dry-type particle size distribution measuring apparatus, characterized in that the circulation path is connected to the container of the disperser via an outward pipe and a return pipe to form a closed circulation path.