JPH0128450Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a particle size distribution measuring device, in particular a device capable of measuring both centrifugal and natural sedimentation modes, which allows the cell to be reliably stopped and set at the measurement position. This invention relates to a distribution measuring device. A centrifugal particle size distribution analyzer has a disk attached perpendicularly to a horizontal motor drive shaft, and a rectangular parallelepiped sedimentation container (cell) attached to the circumference of the disk. Particle size distribution is measured by detecting the light transmittance of the sample liquid, taking advantage of the fact that when particles settle, the sedimentation rate differs depending on their size. This measurement of light transmittance is always performed at a specific position on the rotational orbit of the cell while it is rotating, and detection signals at other positions are ignored. This measuring position is chosen in such a way that it is also possible to carry out measurements under gravity, ie in the natural sedimentation mode, and is usually in a vertical position. However, in the case of natural sedimentation mode, it is not easy to bring the cell accurately to this measurement position, and when it is carried out by visual measurement by the measurer, there is no reproducibility, which may affect the measurement accuracy.

This invention aims to eliminate this inconvenience and provide a particle size distribution measuring device that is easy to handle.

FIG. 1 is a schematic explanatory diagram of a particle size distribution measuring apparatus according to an embodiment of this invention, and FIG. 2 is a front view of its rotating disk. In the figure, a hole in a rotational position detection disk 8 provided separately from a disk 4 on which a cell 3 attached to the horizontal drive shaft of a motor 10 is connected to a position detection light source 7 and a position detection light receiver. The position of the hole is defined so that the cell 3 is located at the measurement position when it comes between the cell 3 and the element 9. At this measurement position, the position detection light receiving element 9 receives the light from the light source 7 and outputs a position detection signal.
A measurement signal transmitted through the light receiving element 2 and detected by the light receiving element 2 is taken into the measurement system via the switch circuit 11. Further, this position detection signal causes the switch circuit 15 to operate and the power source 17 to turn on the indicator light 16. 5 is a rotational balance cell. Therefore, for example, in a centrifugal particle size analyzer, cell 3
The absorbance of cell 3 when there are no particles in the sample liquid is set to zero, and the absorbance when particles at a certain concentration are present in the sample liquid is set as 100, and the cell 3 is rotated to remove particles. The purpose is to observe the change in absorbance during sedimentation, but for this purpose, first put a pure sample solution into cell 3,
It is positioned between the light source 1 and the light receiving element 2, that is, at the measurement position. At this time, if the cell 3 is accurately located at the measurement position, the position detection disk 8 will be located between the position detection light source 7 and the light receiving element 9, and the measurement position indicator light 16 will light up. Therefore, if you fix the disk 4 when this lights up, the cell 3 will be located at the correct measurement position, and the absorbance will be 0 and 100%.
Calibrate with. Note that 12 is an amplifier, 13 is a recorder, and 14 is a calculator, which constitute a measurement system.

On the other hand, when measuring the particle size distribution in the natural sedimentation mode, moving the disk 4 during the measurement will disturb the sedimentation state, so the cell 3 must be fixed at the measurement position from the beginning. That is, in the case of the natural sedimentation mode, the cell 3 is fixed at a position where the indicator light 16 is lit, so that the indicator light 16 is always lit even during measurement.

FIG. 3 shows a modified embodiment of this invention, in which, unlike the switch circuit 15 described above, A,
A switch circuit 18 is used to switch to the B side, and the switch is switched to the A side at the measurement position and to the B side at other locations.A switch 19 is also provided in the B side circuit, and the measurer can close the switch 19 in the natural sedimentation mode. By doing so, the alarm 20 will issue a warning when the cell 3 moves away from the detection position.

In addition, the position detection signal is sent via the servo amplifier.
It is also possible to automatically stop and hold the measurement position by feeding back to the disk drive system.

As mentioned above, in the past, cell positioning was performed arbitrarily and manually during zero and 100% calibration or measurement in natural sedimentation mode, resulting in inaccurate and troublesome operations. It is easy to operate and has excellent reproducibility, and the indicator light flashes during measurement in centrifugal sedimentation mode, lights continuously during measurement in natural sedimentation mode, and has an alarm function, making it highly accurate. measurements can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a particle size distribution measuring apparatus according to an embodiment of this invention, FIG. 2 is a front view of a disk, and FIG. 3 is an explanatory diagram of main parts of a modified embodiment of this invention. 1: light source, 2: light receiving element, 3: cell, 4: disk, 6: motor drive shaft, 7: position detection light source,
8: Disk for position detection, 9: Light receiving element for position detection,
10: Motor, 11, 15: Switch circuit, 1
6: Indicator light.

Claims (1)

[Scope of utility model registration request] A cell to be filled with a measurement sample is installed at a position on the circumference of a disk mounted perpendicularly to the horizontal motor drive shaft, and the cell is loaded at a specific position on the rotational trajectory of the cell.
In an apparatus in which a light source and a light-receiving element are arranged opposite to a disk, and the particle size distribution is measured by changes in light transmitted through the cell, the disk is attached to the motor drive shaft separately from the disk, and this A switch circuit comprising a hole or a protrusion on the disk at a position corresponding to the mounting position of the cell, and a means for optically detecting the hole or protrusion, and selecting a measurement signal from the light receiving element based on a detection signal of the measurement position. 1. A particle size distribution measuring device characterized by comprising means for controlling the cell and displaying that the cell is at a measurement position.