RU2732810C1 - Batch unit for measuring acidity index of solutions - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to the agriculture. Disclosed is a batch unit for measuring acidity in nutrient solutions in growing plants, including a system for measuring and feeding acid solution using indicators. In a large container above the maximum level of the solution there is a smaller capacity for measurements, made of chemically inert material with a measuring glass electrode placed in it, which supplies a signal to a measuring device, which converts the signal into numerical values of acidity. A smaller branch pipe is fed with a branch pipe to feed the calibration fluid therefrom from the other vessel, wherein the second branch pipe supplies the measured solution from the larger vessel to the smaller one.

EFFECT: unit provides higher degree of reliability of produced measurements of acidity.

1 cl, 1 dwg

Description

The invention relates to the field of agriculture, in particular to growing plants in protected soil and can be used in systems for the preparation of nutrient solutions of variable chemical composition and acidity in the cultivation of various crops.

Known technical solution, in which the acidity of the solution is measured by the pH meter by lifting the liquid in a glass calibration capillary with different diameters (patent No. 2315073, published 10.07.2008, Bulletin No. 19. MPK G10N00011, CO2F1 / 46).

This solution is not sufficiently accurate in determining the acidity of the solution, which reduces the quality indicators of the grown plants with an increase or decrease in Ph. Each item in a measurement set requires a cleaning procedure to be performed on the instrument. Therefore, the known technical solution is not effective enough.

It is also known a device for increasing the accuracy of regulating the concentration of a nutrient solution component, which has an acidity control channel, consisting of an acidity sensor, a unit for comparing signals from the output of the latter and signals from the output of the adder, an executive unit connected to the output of the comparison unit and consisting of a regulator and a pump dispenser (and.with. No. 1769815, conventional priority 10/30/1989, IPC А01G 9/24, G 05 D 11/02).

The disadvantage of this technical solution is to ignore the proper working conditions of the glass electrode for measuring pH, which include regular washing of the measuring element with the same regular calibration.

The closest technical solution is a system for measuring acidity Ph, including a set of Ph sensitive elements. Moreover, each indicator is used at different values of Ph, depending on the first Ph response of each indicator (patent No. 2456578, published on July 20, 2012, Bulletin No. 20. IPC G01N21 / 27).

The disadvantage of the closest analogue-prototype is that the used composition of measuring instruments is quite complex at different values of Ph. The introduction of various indicators into the solution complicates the method and reduces the reliability of the result obtained.

The technical result of the claimed invention is to simplify the device by eliminating manual labor for maintenance, increasing the reliability of the results and reliability of work in obtaining the required value of the acidity of the solution

The technical solution consists in the fact that in a large container above the maximum solution level there is a smaller one for measurements, made of a chemically inert material with a measuring glass electrode placed in it, which sends a signal to the measuring device, which converts the signal into numerical values of acidity; a branch pipe supplying the calibration liquid to it from another container, and the second pipe supplying the measured solution from a large container to a smaller one.

The device consists of a working container 1, inside it, above the maximum solution level, there is a small measuring container 2, which is made of a chemically inert material and has a free overflow over the upper edge. In tank 2 there is a measuring glass electrode 3 with the issuance of electrical signals to the measuring device 4, which converts these signals into numerical values of the acidity index. Tank 2 is connected to branch pipe 5 - for pumping 6 calibration liquid from tank 7, as well as branch pipe 8 - for pumping 9 the measured solution in working tank 1 (Figure 1).

The device works as follows.

At the beginning of each measurement cycle, a small amount of the calibration liquid is fed into a small measuring container 2 by briefly switching on the pump 6. The measuring device 4 shows the acidity of the calibration solution, which should coincide with its marking. After that, the pump 9 is turned on for a sufficiently long period of time, while the glass electrode 3 is constantly washed with the measured solution. Measuring electrode 3 supplies the corresponding electrical signals to the converter 4.

After measuring the acidity of the solution in the tank 1, the pump 9 is turned off, then the pump 6 is switched on for a short time to wash the measuring electrode with a portion of the calibration liquid. The measuring electrode 3 is in this environment until the next measurement. The work cycle is over.

Tank for measurements 2 is negligible compared to tank 1, which contains a portion of the measured solution, which each time has a different concentration of salts, alkalis and acids dissolved in it. Therefore, a portion of the flushing (calibration) liquid after performing each measurement does not introduce any noticeable error in the measured value, especially since the upper edge of tank 2 is always located above the solution level in tank 1.

When using the proposed device:

- the degree of reliability of the acidity measurements is increased due to the implementation of the “calibration-measurement-flushing” cycle;

- manual labor is excluded when servicing the measuring device;

- the degree of averaging of the nutrient solution over its entire volume is separated from the process of periodic pH measurements, in connection with which it becomes available to establish a time sufficient to achieve the homogeneity of the solution throughout its volume.

New essential features of the claimed invention:

- the use, along with a large working capacity, of a separate small measuring vessel with a free overflow, into which a measuring element - a glass electrode is constantly immersed;

- the use of independent tanks and pumps to ensure consistent supply of the calibration liquid, the solution to be measured and the flushing liquid to the measuring tank;

- constant presence of the measuring element - a glass electrode in the flushing liquid, which ensures the constant readiness of the measuring element for operation.

Claims (1)

A batch unit for measuring acidity in nutrient solutions when growing plants, including a system for measuring and supplying an acid solution using indicators, characterized in that in a large container above the maximum solution level there is a smaller one for measurements made of a chemically inert material with placed in it a measuring glass electrode supplying a signal to a measuring device that converts the signal into numerical values of acidity, a branch pipe is connected to a smaller container, supplying a calibration liquid to it from another container, and the second pipe supplies the measured solution from a large container to a smaller one.

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