SU1668961A1 - Soil carbonates analyzer - Google Patents

Abstract

The invention relates to agricultural instrumentation and can be used to determine the content of carbonates in the soil in field conditions. The aim of the invention is to improve the accuracy. The analyzer includes a chamber 1 for the material under study with a chamber 2 for a chemical reagent, a pressure meter 6 operational amplifier 7, DC voltage regulators: 8 - with smooth tuning, 12 - with step tuning, amplifier-converter 9, ADC 13 with digital indicators 14. Put soil into the chamber 1 for the material under study, seal the lid 19 and turn it over. Acid interacts with the soil with the release of carbon dioxide. The volume of the latter is proportional to the amount of carbonates in the soil. A pressure gauge 6 registers this parameter, which is displayed on digital indicators 14. 1 sludge.

Description

The invention relates to agricultural instrumentation and can be used to determine the content of carbonates in the soil in field conditions.

The purpose of the invention is to improve the accuracy of the analyzer.

The drawing shows a block diagram of the device.

The soil carbonate analyzer consists of chamber 1 for the material under study, chamber 2 placed in it for chemical reagent. The chamber 1 is connected via a fitting 3 with a protective grid 4, a pneumatic line 5 to a pressure meter 6. A pressure meter 6 is connected to an inverting input (-) of an operational amplifier 7 by its electrical output, and a non-inverting input (-) of an operational amplifier 7 is connected to an regulator 8 eg DC current with smooth tuning. The output of the operational amplifier 7 is connected to the input (Ui) of the converter converter 9.

A temperature sensor 10 placed in chamber 1 for the test material is connected via a matching element 11 to the second input (1) 2) of the converter converter 9, the third input (Uon) is connected to the DC voltage regulator 12 with a stepped setting. The output of the analog-to-digital Converter 13 is connected with digital indicators 14.

For convenience in field conditions, the device can be made in the form

ABOUT

about

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two separate small-sized blocks I and II (marked with a dotted line), which are interconnected by a flexible pneumatic conduit 5 and an electrical wire 15. A belt cover is provided for carrying blocks I and II. Chamber 2 is closed with a stopper 16.

Structurally, the pressure gauge 6 is made on piezoelectric elements, the pressure on which is converted in it into an electrical signal (U). Temperature sensor 10 is semiconductor, the conductivity of the p-junction of which depends on temperature. Operational amplifier 7, amplifier-converter 9, matching element 11 are made on K 140 series microcircuits. Analog-digital converter 13 is made on K 572 series microcircuit with seven segment digital indicators 14 of AL C 333 series.

Chamber t has a recess 17 for installing chamber 2, the soil under study 18 is placed in chamber 1. Chamber 1 has a cover 19. Regulator 8 has a potentiometer 20 for smooth tuning, and regulator 12 has a switch 21.

The device works as follows.

The kit contains several chemical reactant chambers 2 pre-filled with hydrochloric acid solution, the neck of which is closed with a stopper 16. One of these chambers 2 is placed in chamber 1 for the material under investigation in a special recess. A portion of the test soil 18 is poured into chamber 1, the plug 16 is removed from the neck of chamber 2. After that, the chamber 1 is hermetically sealed with a lid 19. The potentiometer 20 of the DC voltage regulator 8 sets zero readings at the output of the analog-to-digital converter 13. The readings are measured visually on the digital indicators 14. Thus, the effect of the initial pressure the camera 1 when screwing the cover 19, on the measurement results. This preparatory stage ends.

After that, the block chamber 1 is turned upside down, the acid is poured out of chamber 2, and the soil is poured out of chamber 1 into cover 19. The hydrochloric acid solution chemically reacts with the carbonates of the soil, and carbon dioxide is released.

The amount of carbon dioxide released is proportional to the amount of carbonates in the soil.

In chamber 1, an excessive gas pressure is formed, which is proportional to the amount of carbonate in the soil. At the exit, the meter

pressure 6, a stress arises in proportion to the amount of carbonates in the soil. This voltage is amplified by the operational amplifier 7 to the required

magnitude (about 10 times) and is fed to the first input of the amplifier-converter 9.

At the same time, the electrical signal from the temperature sensor 10 through the matching element 11 is fed to the second input (IJ2) of the converter converter. This signal is proportional to the actual temperature of the gas mixture in chamber 1. Thus, the effect of changes in soil temperature, air, chamber body 1 from the heat of hands and other on the results of measuring the carbonate content in the soil is taken into account.

The third input of the amplifier-converter 9 receives a voltage (Don) from the regulator 12 of the DC voltage with a stepped tuning. The switch 21 of this controller has three fixed positions x1, xy, xyoo,

which allows the scale of the transformation to be changed stepwise in the appropriate number of times, depending on the amount of carbonates in the soil.

Thus, at the output of converter E, the output voltage (Uf-s) is proportional to the amount of carbonates in the soil, taking into account the actual temperature of the gas mixture in chamber 1.

In this case, the conversion formula is

Ui - KU2

Ub

ban

where Ui is the voltage proportional to the amount of carbonates in the soil;

U2 is a proportional voltage

temperature of the mixture in the chamber 1;

Which voltage varies in steps, which changes the scale of the conversion 10 and 100 times:

к is a coefficient equal to ± 1 depending on the increase or decrease in the temperature of the gas mixture in chamber 1 relative to the calculated temperature of + 20 ° C. The output voltage of the U-out is supplied

to the information input of the LM analog-to-digital converter. The result of the conversion displays the actual carbonate content in the soil and is displayed on seven-segment indicators 14

in digital form.

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION A soil carbonate analyzer comprising a chamber for a test material with a chemical reactant chamber located therein and a pressure meter connected to the test material chamber, characterized in that it is equipped with a temperature sensor with matching element to increase the analyzer accuracy. voltage regulator with smooth tuning, operational amplifier, voltage regulator with step tuning, converter amplifier, the output of which is connected to the analog input -Digital converter with uz0 display indicator, the output of the pressure gauge is connected to the inverting input of the operational amplifier, with a non-inverting input of which the output of the voltage regulator is connected with a smooth tuning, and the output of the operational amplifier is connected to the first input of the amplifier-converter, the second input of the last connecting with the output voltage regulator with step adjustment, s the third input - with the output of the matching element. one(- 2 17 Ю 15 2112 13