RU208431U1 - Portable device for rapid analysis of free chlorine and pH in water - Google Patents

Abstract

The utility model relates to the field of monitoring the content of free chlorine and pH after the process of water purification and disinfection, namely, to a portable device for express analysis of free chlorine and pH in the water of water facilities by photometric method. The technical result is to increase the accuracy of measuring the concentration of residual chlorine and the level of the hydrogen index in the water of water facilities. The claimed technical result is achieved due to the fact that a portable device for express analysis of free chlorine and pH in water contains a housing with a digital display, in which a power source is located in series, a measuring module containing a light source, which is used as a high-power LED RGB white light, an interference filter with a band at 525 nm (green), a measuring cell, a cuvette fixation system, a detector, which uses an RPP130 photoresistor based on cadmium sulfide, and an information processing module that contains a microprocessor and an LM358N amplifier. An electronic voltage stabilizer can be used as a power source. In another particular embodiment of the device, the detector housing can be made of styrene. The case of a portable device for rapid analysis of residual chlorine and pH in water may have an opaque coating. 3 w.p. f-ly, 2 figs.

Description

The utility model relates to the field of monitoring the content of free chlorine and hydrogen index after the process of purification and disinfection of water, namely, to a portable device for express analysis of free chlorine and hydrogen index in water of waterfaring facilities by the photometric method.

Currently, express devices are known for determining the concentration of free chlorine, which are based on semi-quantitative measurement methods. In the booklet [Instruction Manual HU 3831 F Free Clorine Test Kit; https://docs.rs-online.com/d2f0/0900766b805cc9a2.pdf] describes a device consisting of a tester body, tester cover, reagent tablets (phenol red indicator, diethylparaphenylenediamine). Concentration measurement using this device occurs by determining the color intensity of the test solution after adding reagent tablets to it. The reagent colors the chlorine-containing solution in a certain color of the red part of the visible spectrum. By comparing the color intensity of the solution with the standard (for this method) color scale, the content of free chlorine in the analyzed sample is determined with a volume of 250 ml, with a chlorine content of more than 0.3 mg / l.

The proposed device has simplicity of analysis and does not require sample preparation of the analyzed water, however, the disadvantages of the method are low sensitivity and low reliability of measurement results (about 70%).

The closest analogue of the claimed utility model (prototype) is a portable photometer HI-96725, which is designed to measure water indicators [http://www.td-anion.ru/catalog/analizatory-razlichnye/hi-96725-analizator-hlora.htm ]. The known analyzer contains a housing with a digital display, which contains a power source, a measuring module containing a light source, an interference filter with a band at 525 nm (green), a measuring cell, a cell fixation system, a detector and an information processing module consisting of a microprocessor, and See also the power supply (battery) and battery indicator. A narrow strip tungsten lamp is used as the light source, and a silicon-based photocell is used as the light detector.

The known device for determining the content of free and total chlorine uses an adapted method with diethylparaphenylenediamine; the phenol red method is used to determine the pH. Depending on the parameter being measured, reagents are used in the form of powders or in liquid form. After adding the required reagent to the sample, the sample changes color; the higher the concentration, the brighter the color. The resulting color change is then colorimetrically analyzed in accordance with the Lambert-Beer law. For characterization purposes, a 525 nm (green) narrow band interference filter allows only green light to pass to the silicon photodetector and excludes the rest of the visible light spectrum emitted by a tungsten lamp. An increase in the color intensity of the reacted sample leads to an increase in the absorption of a specific wavelength of light and a decrease in the transmittance.

The disadvantage of this device is the low measurement accuracy, which does not allow determining the measurement reliability with equal accuracy (10% for pH and 3% for free chlorine).

Disclosure of the essence of the utility model.

The problem to be solved by the claimed utility model is the development of a portable device with high accuracy of measuring the level of residual chlorine and hydrogen index in the water of waterfaring facilities.

The technical result is to improve the accuracy of measuring the concentration of residual chlorine and the level of pH in the water of waterfaring facilities.

The claimed technical result is achieved due to the fact that a portable device for express analysis of free chlorine and hydrogen index in water contains a housing with a digital display, in which a power supply is located in series, a measuring module containing a light source, which is used as a high-power LED-light-emitting diode white light RGB, an interference filter with a band at 525 nm (green), a measuring cell, a cell fixation system, a detector, which is a cadmium sulfide photoresistor RPP130, and an information processing module, which contains a microprocessor and an LM358N amplifier.

An electronic voltage regulator can be used as a power source. In another particular case of the device, the detector housing can be made of styrene. The case of the portable instrument for the rapid analysis of residual chlorine and pH in water may have an opaque coating.

The essence of the utility model is illustrated by drawings: FIG. 1 shows a diagram of the claimed device; in fig. 2 is a schematic electrical diagram of the device.

Where in Fig. 1:

1 - Housing;

2 - Digital display;

3 - Power supply;

4 - Measuring module;

5 - Light source;

6 - Interference filter with a band at 525 nm (green);

7 - Measuring cell;

8 - Ditch fixation system;

9 - Detector;

10 - Information processing module;

11 - Amplifier LM358N;

12 - Microprocessor.

Where in fig 2:

LED - RGB white light-emitting diode;

LDR - cadmium sulfide photoresistor (sensitivity range 520-700 nm);

LM358N - operational amplifier based on a non-inverting DC amplifier;

R1, R2 - trimmer resistors;

R3, R4 - negative feedback resistive circuit;

C1 is a constant capacitor.

A portable device for the express analysis of free chlorine and pH in water consists of a housing (1), which can have a light-tight coating, with a digital display (2) for broadcasting information when measuring water indicators, with a power source located in series in it (3) , which can be used as an electronic voltage stabilizer; measuring module (4), which consists of a light source (5), which is a white LEG LED, an interference filter with a green spectrum band at 525 nm (6), a measuring cell (7), a cell fixation system (8), a detector in the form of an LDR photoresistor based on cadmium sulfide with the highest sensitivity range of 520-700 (9), and an information processing module (10) containing an LM358N operational amplifier (11) according to the circuit of a non-inverting DC amplifier and a microprocessor. (12).

An LDR photoresistor, used as a detector and having spectral characteristics that fully correspond to the spectral sensitivity of the eye, allows fixing the visible spectrum of light, and the use of a white LED light-emitting diode as a light source allows, due to the lack of inertia of switching on (the maximum brightness of radiation is achieved immediately after switching on) high color rendering coefficients CRI and light output, which makes it possible to increase the accuracy of measuring the concentration of free chlorine in water by the claimed device by 1.5 times, and the pH level by 10 times in comparison with the prototype. The use of an electronic voltage regulator as a power source (3) additionally allows maintaining a stable voltage over a wide range of input voltages, thereby ensuring high measurement accuracy.

, в случае измерения водородного показателя в диапазоне концентраций от 6,5 до 8,6 ед. pH составила

ед. pH. Точность измерений в случае концентрации свободного хлора определялась путем создания модельных растворов с заранее известной концентрацией. В случае определения водородного показателя использовался pH-метр с погрешностью измерения 0,01 ед. pH и диапазоном чувствительности от 0,00 до14.00 измерительных единиц.The measurement error of the device in model solutions with free chlorine concentrations in the range from 0.2 mg / L to 6 mg / L was

, in the case of measuring the pH in the concentration range from 6.5 to 8.6 units. pH was

units pH. The measurement accuracy in the case of free chlorine concentration was determined by creating model solutions with a previously known concentration. In the case of determining the pH, a pH meter was used with a measurement error of 0.01 units. pH and sensitivity range from 0.00 to 14.00 measuring units.

The device works as follows.

To determine the concentration of free chlorine, a water sample is poured from the pool into a cuvette and placed in an opaque measuring cell (7) with a cuvette fixation system (8), which ensures the same position and works according to the lock and key principle. The original composition of the sample is controlled by an automatic “zero” calibration on the digital display (2). Then a diethylparaphenylenediamine (DPD-1) indicator test tablet is added to the cuvette, after which the sample acquires a certain color of the red part of the spectrum, which depends on the concentration of free chlorine dissolved in water. The luminous flux from the light source (5), passing through the colored model solution, is partially absorbed by it. Part of the unabsorbed light flux acts on the detector (9). As shown in FIG. 2 trimming resistors R1, R2 form a voltage divider from which the measured electrical signal is fed to the non-invertible input of the amplifier (11). In order for the operation of the operational amplifier (11) to be controlled, negative feedback is applied, which consists of a resistive circuit R3, R4, which is set by supplying part of the voltage from the amplifier output to its inverting input. By changing the parameters of the resistive negative feedback circuit R3, R4, the amplifier's input sensitivity is adjusted. The signal is processed at the input of a digital block of information. As shown in FIG. 1 microprocessor (12) calculates the free chlorine content depending on the signal voltage and displays the result on the display (2).

To determine the pH level, a similar principle of operation of the device is used, the difference of which is the use of another indicator test to change the color of the sample - phenol red.

Claims (4)

1. A portable device for express analysis of free chlorine and pH in water, containing a housing with a digital display, in which a power supply is located in series, a measuring module containing a light source, an interference filter with a band at 525 nm (green), a measuring cell, a system for fixing cuvettes, a detector and an information processing module containing a microprocessor, characterized in that the information processing module is additionally equipped with an LM358N amplifier; A high-power RGB white LED is used as a light source, and a cadmium sulfide-based RPP130 photoresistor is used as a detector. 2. The device according to claim 1, characterized in that an electronic voltage regulator is used as a power source. 3. The device according to claim 2, characterized in that the detector housing is made of styrene. 4. The device according to PP. 1-3, characterized in that the case of the portable device for the rapid analysis of residual chlorine and hydrogen index has an opaque coating.

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