SU842496A1 - Device for counting and determination of particle sizes in optically dense media - Google Patents

Description

analyzed medium. This leads to the complication of the hydrodynamic channel of the device and limits its scope for the analysis of various dispersion systems.

The closest in technical essence to the present invention is a device containing a rectangular cross section cuvette, an illuminator that forms a registration area in a cuvette, a photo receiver that detects light flashes scattered by particles when passing the registration area, and located at an angle of 90 to the axis; and an electronic unit for processing electrical signals SCH1. However, in the indicated device, when analyzing optically dense dispersion systems, the distribution curve of the analyzed particles in size is broadened. Depending on the location of the scattering particle, the light rays in the cell pass a different geometric path, and the signal amplitude from the particle differs by an amount proportional to the difference in the absorption of these rays by the medium being analyzed. The broadening of the distribution curve becomes significant for optically dense dispersion media and for a large base cell.

The purpose of the invention is to improve the accuracy of determining the number and size of particles.

The goal is achieved in that a device for counting and determining particle sizes in optically dense media, containing an illuminator, a measuring cell of a rectangular section, a photodetector registering scattered radiation, and an electronic signal processing unit, have two attenuators with variable optical density, the first the attenuator is located between the illuminator and the entrance window of the cuvette, and the second attenuator is located between the exit window of the cuvette and the photodetector.

JCpOMe, the attenuators are made in a VMde transparent cells, having the form of rectangular triangular prisms, and set so that their faces opposite the refracting angles are in the planes of the output and input windows of the cuvette, respectively.

The attenuator can be made in the form of an optical wedge from neutral glass, a dashed optical wedge, or a prismatic cuvette of a triangular cross section. Before carrying out the analysis, the internal cavity of the attenuator cell is filled with the analyzed medium, the optical density of which coincides with the optical density of the test.

The drawing shows a diagram of the proposed device.

The device contains an illuminator 1, attenuators 2 and 3 with a linearly varying optical density (optical wedges), a measuring cell 4 of rectangular cross section with translucent input and output windows, a photodetector 5 and an electronic unit 6 for signal processing.

The device works as follows.

The luminous flux from the illuminator 1 passes the attenuator 2 and through the input window into the measuring cell to form in it a brightly lit registration area. Part of the light flux scattered by the particle 7 when passing through the registration zone passes through the exit window of the cell, the attenuator 3 and hits the entrance pupil of the photodetector 5. The signals received from the photoreceiver output are processed by the electronic unit 6.

Beam A when passing through the measuring cell in the direction of the axis of the illuminator is absorbed by the dispersion medium to a lesser extent than beam B. Absorption of beam A, compensating for the difference in attenuation of beams A and B, occurs as it passes through a linear attenuator 2. The mechanism the attenuation of the rays A and B after scattering on the particle 7. The difference in attenuation of the scattered rays is compensated for in the linear attenuator 3.

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The parameters of the attenuators 2 and J are selected depending on the absorption coefficient of the dispersion medium and the parameters of the cross section of the measuring cell.

The proposed device allows the range of the analyzed media to be expanded, thereby increasing the accuracy. Determining the number and size of particles. Its use is especially effective for comrades whose optical density is greater than the optical density of water.

Claims (4)

1. A device for identifying and determining particle size in optically dense media containing a lighter, a measuring cell of a rectangular cross section, a photodetector registering scattered radiation, and an elecrtic signal processing unit, characterized in that, in order to improve the accuracy of quantity determination and dimensions of particles, two attenuators with variable optical density are introduced into it, with the first attenuator located between the illuminator and the entrance window of the cuvette, and the second attenuator is between the exit window of the cuvette and the photodetector, 2. The device according to claim 1, characterized in that the attenuators are made in the form of translucent angles that have the shape of rectangular triangular prisms, and are set like this. that their edges opposite the refractive angles are in the planes of the output and input windows of the cuvette, respectively. Sources of information taken into account in the examination 1. Patent of Japan, No. 51-22396, Kji. Ml T 2, pub. 1976. 2.Patent of Germany If 1673132, cl. S 01 M 15/00, published 1973. 3.Patent of France No. 2065190, cl. 6 About N 15/00, .public. 1971. 4.E.Alexander Marlens. Errors in Mesurements and Counting of Articles using Zight Scattering. - Journal of the Air Pollution Control Association, 1968, vol. 18, 10, p. 658 (prototype).