RU1777054C - Concentration meter - Google Patents

Abstract

Usage: analytical instrumentation, spectrophotometry for process control. The inventive concentrator contains a radiation source, lenses, two cuvettes, two mirrors and a photodetector consisting of a rotating interference filter made with the possibility of changing the angle of inclination to the axis of its rotation, as well as the angle between the axis of rotation and the axis of the cell, scattering cameras and photodetector. 1 ill.

Description

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The invention relates to analytical instrumentation and can be used to measure the concentration of various elements in optically transparent media according to the characteristics of the absorption spectra.

The aim of the invention is to increase the selectivity of analysis in complex technological solutions.

This goal is achieved by the fact that a second reference channel is introduced into the concentrator, and the reference and measuring channels are arranged so that the angles between the channel axes and the axis of rotation of the filter are equal in total to the angle between the channel axes and both channels have a common interference filter and a photodetector.

The drawing shows an optical diagram of a concentrator.

The concentration meter contains a radiation source 1, two diaphragms 2, two lenses 3, two reflective mirrors 4, two cuvettes 5,

interference light filter 6. integrating camera 7 and photodetector 8.

The device for separating the light beam is an angular screen with two diaphragms. The planes of the angular screen 2, lenses 3, mirrors 4, cuvette 5 can be installed at different angles to the axis of symmetry of the circuit, pass through the center of the interference filter to the filament of the emitter source in such a way that "1 a2 or.

The interference filter is made with a rotation drive and with the possibility of changing the angle of inclination to the axis of its rotation, as well as the angle of inclination to the axis of symmetry of the circuit passing through its center.

According to the invention, the concentration meter works as follows

Two rays, formed from one light source 1 and through the diaphragms 2. of the lens 3, are reflected by the mirrors 4 and pass through one cell, respectively

at

3

with the analyzed sample, and the other through the cuvette with the reference sample, the interference filter b, integrating the camera 7 and simultaneously detected by the photodetector 8, the channels are located at some angles at and ai to the axis of rotation of the filter so that the sum of the angles ai + 0.1 is equal to the angle between rays. Since the plane of the filter, in turn, is inclined to the axis of rotation at a certain angle, when the filter rotates, the angles of incidence of the rays on the filter change in antiphase ranging from Ai (A1) to A a ("2) also in the proto phase where Ai is the wavelength of the maximum transmittance of the filter when the beam falls on the filter at an angle ea - / 3; A2 - the same when the beam falls on the filter at an angle u + / 3. In that case,

if "1" 2 p, in the range of wavelengths from

Ai to Ar, the optical density varies linearly (which is done with a small difference AI-Aa). The total intensity of the light incident on the photodetector will be modulated only if the dependence of the optical density or transmission in the wavelength region between Ai and Kg for two samples is distinguishable, i.e. only with a difference in the material composition of the sample and the sample. Moreover, the modulation depth at fixed angles is proportional to

Tnp (Al) - TPR (A2) - T0br (A) - Tobr (A2)

or

ATpr DTobr -2STST

This allows you to measure DL / DY (DT / YES) or A (Ai) -A (Az) for

samples relative to a similar value for the sample. In the general case, at A1 (w) Ar ("2), the values of the derivatives of optical density or transmission in

different spectral regions for the analyzed and standard samples. The presence of angles between the channels and the axis of rotation of the filter and the possibility of changing the angle / 3 of the inclination of the filter to the axis of rotation allow measurement of the relative difference between the first derivatives of optical densities or transmittances in the interval between two wavelengths of Ach and Ar for two (analyzed and standard)

samples at the same time, which in turn

allows you to combine the advantages of differential and derivative spectrophotometry; in particular, this allows

first derivative method, where maxima

The transmission of the complex-complexing agent complex and the complexing agent itself are close or coincide.

Claims (1)

The claims Concentrator comprising an optically coupled radiation source, a measuring channel, an interference filter with a rotation drive, mounted so that the axis of rotation of the filter makes an acute angle with the optical axis of the measuring channel, and an angle different from the direct with the plane of the filter and a photodetector comprising an integrating camera and a photodetector, characterized in that, in order to increase the selectivity of the analysis, a reference channel is optically coupled to the radiation source and the filter so that cally component with an axis the axis of rotation of the filter is an acute angle, and the sum of the angles between the axis of rotation of the filter and the optical axis of the channels is equal to the angle between the optical axis of the channels. cvi