SU137689A1 - Automatic refractometer - Google Patents

Description

BASIC Auth. St. No. 130210 describes an automatic refractometer, in the follow system of which a thermal compensation device is used, consisting of a thermistor and a calibrated resistance.

In the proposed automatic refractometer - a device for measuring, recording and controlling the concentration of sugar (solids) in the wash water, instead of the specified temperature compensating device, an optical thermal compression device is used, which provides automatic compensation for temperature error and provides more accurate readings.

The drawing shows an electrical diagram of a refractometer with an optical temperature compensating device.

From the light source 1, the beam through the filter 2 and condenser 3 impinges on the measuring prism 4 washed by the wash water (containing sugar - dry matter). Part of the light beam is absorbed by the washings, and the rest of it is completely reflected in the prism. The reflected beam exits the prism 4 and forms the bright part of the floor. The border between the light and the dark part of the floor (the border of light and shade) is formed by the limiting ray of reflection; The position of the light intensity boundary is determined by the refractive index of the measured solution. The exit from the measuring prism 4 uch (light intensity limit) is projected by a two-lens 5-6 lens and a block 7 of photoresistances, reflected from the mirror S.

Along the second branch, the beam from the light source 1 through the light filter 9 and the condenser 10 falls on the measuring lens 11, the flat surface of which is in contact with the exemplary liquid (mixed water). The beam (chiaroscuro border), emerging from the prism 11, is projected by a two-lens lens 12-13 on the block 14 of photo-motivations, reflected from the mirror 15.

No. 137689-2 -

Wash waters are constantly washed in a cuvette with an exemplary liquid, which accepts temneruru wash water (this contributes to the thin wall of the brass cuvette). The voltage from the bridge diagonal, the shoulders of which include blocks 7 and 14 of photoresistances, is fed to the input of the electronic bridge amplifier. The output of the amplifier of this bridge is connected to a reversible electric motor, 16, which is connected via a gearbox to the electronic bridge by means of a selsyn-sensor 17, connected to a selenium-irieman 18, located in the concentration sensor, and a selsyn. - an original of a selsyn indicator (not shown in the drawing). A sealsin receiver 18 is connected by means of a cam to a mirror 8.

In the equilibrium state of the follow-up system, the light-shade boundary from prism 4 is projected onto the central part of the photoresistance block 7, and the light-shadow angle from prism 11 to the central part of the / - / photoresistance unit. With this. M, a useful cod at the exit of the power bridge is not sufficient to drive the reversing motor and the selsyn-sensor. The concentration of sugar (dry matter) in the wash water leads to a shift in the light and shade boundary, and the photoresistance unit 7 is in the light or dark zone. A beam (the shadow border) is projected onto the photoprotection unit 14, the position of which in space does not depend on the change in concentration, but depends on the change in the telorate of the sample solution. Depending on which part of the beam falls on the block of photoreactives 7 (dark or bright nOoie), the output voltage of the amplifier of the electron bridge is determined, which causes the rotation of the reversing motor 16, the selsion sensor 17, the selsina 18 and the mirror 8 The receiver-18 18 grows mirror 8 in such a way that the light intensity is projected onto the photoresistance unit 7; , returns to its original position, which corresponds to the equilibrium equilibrium trace n1, with which it is measured. The angle of rotation of the tractor 17 to bring the light from 1 to 1 into the initial position is proportional to the change in the concentration of sugar (dry matter) in the washing waters and is fixed on the cheek, on the electronic bridge and on the scale of the selsyne indicator (readings are shown at i; temperature 20 °).

The compensation is varied} and the refracted index npo.AHjHiHbbx of water from temperature change, is carried out by the second branch of the optical circuit (optical filter 9, condenser 10, prism 11, two-lens 12-13 lens and mirror 15). If, following the spraying of the tempered water temperature, at a constant concentration, the position of the light and shade on the photoresistance block 7 changes, the position of the light and shade on the photoresistance block 14 changes accordingly due to the temperature of the sample solution. As a result, the voltage across the diagonal of the bridge, in whose shoulders there are built-in blocks of photoresistance, will be zero and the refrastometer will not have its own readings. Since the measured and sample fluids have the same temperature coefficient, the prisms 4 and // are similar to each other, and the photoresistance blocks are located at the same distance from their projection lenses at different focal lengths, the same linear displacement of the light and shadow boundaries in both branches of the optical system. In both arms of the bridge circuit, the block resistances change by the same amount and, as a result of this, the equilibrium state of the tracking system is not disturbed.