RU2415399C1 - Water analyser - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: water analyser comprises case to accommodate measuring cylinder. Besides, it comprises light source, at least, three photo receivers to fix light reflected by suspension particles, and photo receiver to fix light flux that passed through analysed medium. Also, proposed device comprises resistance thermometre, water filling pickup, inlet and outlet branch pies with solenoid valves, two annular electrodes and control unit. Note here that said device comprises additionally two measuring cylinders arranged in the same case with bottom accommodating cups of high-accuracy scales. Note also that the case additionally incorporates measuring graphite electrode, copper comparison electrode, stainless steel auxiliary electrode, combined pH-electrode and combined redox-electrode. Mind that light source is equipped with light filters with wavelength of 380, 400, 410, 500 and 800 nm.

EFFECT: high accuracy of measurements, automatic analysis.

4 dwg

Description

The invention relates to devices for analyzing water according to the following characteristics: turbidity, color, temperature, sedimentation analysis, electrical conductivity, viscosity, electrophoretic mobility, zeta potential of suspended particles, chemical oxygen demand, chlorine content, hydrogen index and redox potential and can be used for monitoring water bodies, technical and drinking water supply.

A device is known for providing sedimentation analysis of water and measuring its turbidity [1]. This device transmits the stationary volume of the transparent dispersion medium (water) by the light flux in the direction of sedimentation of particles and registers the light flux in the direction of sedimentation, and also, after a certain period of time after the start of the measurement, at least three levels scattered by the particles of light in the direction perpendicular to the movement of particles. Based on the results obtained, the sedimentation rate of the particles and the turbidity of the water are calculated. The main disadvantages of this device are: a small number of controlled characteristics of the same water sample, the lack of functionality to select modes and ensure the necessary measurement accuracy, as well as the limitations associated with the inability to analyze high turbidity waters.

A device is also known for analyzing water according to indicators of sedimentation analysis and turbidity, in which a controlled electric field is exposed to a uniform electric field in the direction coinciding with the direction of sedimentation of particles on a cup of torsion balance [2]. The main disadvantages of this device are: a small number of controlled characteristics of the same sample, as well as the lack of functionality for choosing measurement modes.

Closest to the invention is a device for water analysis, which allows you to analyze the same water sample in automatic mode by turbidity, conductivity, electrophoretic viscosity, zeta potential of the suspension, to obtain sedimentation characteristics of this suspension [3]. The main disadvantages of this device are: a small number of controlled characteristics for an overall assessment of water quality, as well as the lack of functionality to select modes and ensure the necessary measurement accuracy.

The aim of the invention is the creation of a device for water analysis, which allows you to perform analyzes of the same water samples in an automatic mode on an extended set of characteristics: turbidity, color, temperature, sedimentation analysis of suspension, electrical conductivity, viscosity, electrophoretic mobility, zeta potential of suspension particles, chemical oxygen requirements, chlorine content, hydrogen index and redox potential, using the functionality of the choice of measurement modes and ensuring the necessary In winter accuracy.

This goal is achieved in that a water analysis device comprising a housing and a measuring cylinder located therein with devices for cleaning its walls and bottom, a light source, at least three photodetectors that record the light reflected by the particles of the suspension, a photodetector that records the luminous flux transmitted analyzed medium, resistance thermometer, water filling sensor, inlet and outlet nozzles with electromagnetic valves, two ring electrodes and a control unit, additionally contains two measuring cylinders ra located in the same housing, in the lower part of which there are cups of high-precision scales, the housing additionally containing a measuring electrode of graphite, a comparative electrode of copper, an auxiliary electrode of stainless steel, a combined pH electrode and a combined redox electrode, and a light source equipped with filters with wavelengths of 380, 400, 410, 500 and 800 nm.

The location of three measuring cylinders in one housing allows the analysis of the same water sample in automatic mode by an expanded set of characteristics, which together make it possible to obtain wide information about water quality. The amount of this information obtained over short periods of time at short intervals is sufficient to make operational decisions on the regulation of water treatment technology and on the possibilities of its use. In addition, this arrangement makes it possible to accelerate the measurement process, since a number of indicators can be controlled simultaneously. An increase in the number of cylinders makes it possible to increase the accuracy of measurements, in particular optical, since in this case there is no need to place ring electrodes in the “optical” cylinder, which, when a uniform potential difference is created between them, reduces the accuracy of measuring optical characteristics.

The location of the cups of the cups of high-precision scales in the lower part of the “non-optical” cylinders in the presence of ring electrodes in the upper and lower parts of one of them allows for high-precision sedimentation analysis, determination of electrophoretic mobility, turbidity, electrical conductivity and zeta potential, which, in turn, expands the functionality of the choice of measurement modes. In particular, it is possible to perform sedimentation analysis and measure the turbidity of water in two ways: one optical - accelerated, the duration of which can take several seconds, and the other - “weight”, which, depending on the required measurement accuracy, can be carried out for about ten minutes less.

The location in the housing between its walls and the walls of the cylinders of the measuring electrode of graphite, a comparative electrode of copper, an auxiliary electrode of stainless steel, a combined pH electrode and a combined redox electrode also allows you to analyze the same water sample in an automatic mode for an extended set characteristics, which include: chlorine content in water, hydrogen index and redox potential.

Providing a light source with filters with wavelengths of 380, 400, 410, 500 and 800 nm also allows you to analyze the same water sample in automatic mode by an expanded set of characteristics, which include chemical oxygen demand and water color. At the same time, the functionality of the choice of measurement modes is expanded, in particular, when determining color, it is possible to perform measurements in two ways: on a chromium-cobalt color scale using a 380 nm filter, and a platinum-cobalt color scale on a 410 nm filter.

Figure 1 presents a General diagram of a device for water analysis; figure 2 - arrangement of cylinders and combined electrodes in plan and vertical sections.

The device for analyzing water in figures 1 and 2 consists of a cylindrical body 1, inside of which are measuring cylinders 2, 3 and 4, the body and cylinders made of electrically conductive material, and the walls and bottom of cylinder 3 are transparent; photodetectors 5 are integrated in the walls of the cylinder 3, at least in three levels, detecting the light scattered by the particles in the direction perpendicular to the movement of the settling particles, and a photodetector 6 is built into the bottom of this cylinder to register the light flux in the direction of particle settling. The device also contains solenoid valves 7 and 8, respectively, on the supply pipes 9 and water outlet 10; two electrodes 11 and 11 located in the upper and lower parts of the cylinder 2 to create a constant electric field; three electrodes: measuring 12 of graphite, comparative 13 of copper and auxiliary 14 of stainless steel, located in the space between the walls of the housing 1 and cylinders 2 and 4; a combined pH electrode 15 located in the space between the walls of the housing 1 and cylinders 2 and 3, a combined redox electrode 16 located in the space between the walls of the housing 1 and cylinders 3 and 4; light source 17; a set of five filters 18 for creating light with wavelengths of 380, 400, 410, 500 and 800 nm; two cups 19, which are sensitive elements of high-precision scales, located in the lower parts of the cylinders 2 and 4; resistance thermometer 20; filling sensor 21; control unit 22; non-volatile memory 23; a transmitter 24 and a direct current source 25. All measuring cylinders have covers with perforations 26 through which they are uniformly filled. To drain water from the cylinders 2, 3 and 4 into the pipe 10, pipes 27 are provided.

The device operates as follows:

In accordance with the technological regulations for the operation of the device, the following settings are entered in the control unit:

- choice of measurement mode;

- time interval between measurement cycles;

- calibration characteristic established for aqueous solutions of platinum-cobalt color scale [4];

- calibration characteristic established for aqueous solutions of chromium-cobalt color scale [4];

- the constant of the vessel (cylinder 2) [3];

- temperature corrections [3].

The setting “selection of measurement mode” provides for the possibility of setting modes for individual indicators of water quality, integrated modes and full mode.

Modes for individual indicators, for example, include: determination of turbidity of water by the optical method; sedimentation analysis with the determination of turbidity by the optical method; determination of chemical oxygen demand; determination of pH; determination of chlorine content; determination of temperature; conductivity determination; determination of color by the photometric method on a platinum-cobalt scale; determination of color by the photometric method on a chrome-cobalt scale.

Complex modes, for example, include: determination of temperature — viscosity, — electrophoretic mobility — sedimentation analysis — calculation of the zeta potential; color definition in two ways.

There is also the possibility of choosing complex modes according to sets of individual indicators.

The full measurement mode provides for the determination of all twelve indicators of water quality using "duplicate" methods for determining turbidity, color and sedimentation analysis.

At the signal of the control unit 22, the valve 7 on the water supply pipe opens, the housing 1 begins to fill. When the water rises to the height of the measuring cylinders 2, 3 and 4, they begin to fill through the perforated lids. After filling the measuring cylinders 2, 3 and 4, the water rises higher in the housing 1 and reaches the filling sensor 21, at the signal of which the control unit closes the solenoid valve 7. The water supply is interrupted. Thus, stationary volumes of water are installed in the housing and measuring cylinders.

In the full measurement mode, the signal source 17 is turned on by the signal from the control unit 22, such switching is carried out in advance so that the light intensity of this source is stabilized. At the same time, measurements begin in all three cylinders. Using a resistance thermometer 20, the temperature of the water sample is measured. The temperature control unit 22 determines the dynamic viscosity of water [7] according to the formula

where t is the temperature of the water, ° C.

The control unit 22 sends the received data to the non-volatile memory 23. A constant electric field is created in the cylinder 2 by means of the electrodes 11, at the same time as the electrodes 11 are turned on, the timer is turned on in the control unit 22. Under cylinders 2 and 4, the scales measure the mass of particles deposited on the corresponding cups, these data are continuously supplied to block 22, which records the change in mass over time and constructs sedimentation curves I and II according to a predetermined algorithm [2]. Under the influence of a constant electric field, particles in cylinder 2 settle faster than in cylinder 4, therefore, curve I “straightens” earlier than curve II. After straightening, block 22 turns off the timer. According to the data of weights 19, turbidity is determined in cylinder 2. Data on sedimentation curves and turbidity are recorded in non-volatile memory. Comparing the two obtained sedimentation curves, block 22 determines the electrophoretic mobility and zeta potential using a predetermined algorithm. These two indicators are stored in non-volatile memory 23 of the device. On this, the measurements in the two cylinders 2 and 4 are finished. After the timer is turned off, the resistivity is determined in block 22 and the electrical conductivity of water is calculated by the method described in [3]. Simultaneously with the start of measurements in cylinders 2 and 4 in cylinder 3, the measurement of chemical oxygen demand (COD) begins [5]. Light with a wavelength of 400 nm passes through the filter; the photodetector detects the strength of this light that has passed through the sample. The light turns off, the filter changes from 400 nm to 500 nm. Measurements are repeated at a given wavelength. Then the filter changes from 500 nm to 800 nm. Measurements are repeated. Using three measurements of the photodetector, the absorption coefficient of light at different wavelengths is determined; according to these data, block 22 calculates COD. Then, in the same cylinder, the measurement of color begins using filters at 380 and 410 nm [4].

At the same time, in the cylinder body 1, the pH measurement begins [8], and then the redox potential [9] using combined pH and redox electrodes [10]. After that, the residual chlorine is measured using the measuring, comparative and auxiliary electrodes located in the cylinder body 1 [6]. A constant voltage is applied between the graphite measuring electrode 12 and the auxiliary stainless steel electrode 14 so that the potential of the graphite measuring electrode 12 relative to the copper comparative electrode 13 is in the range from +150 to -200 mV (at a chlorine concentration in water of 0 up to 5 mg / l). Under these conditions, the magnitude of the current flowing between the measuring electrodes 12 and auxiliary 14, is directly proportional to the concentration of residual chlorine in the water.

The obtained data on COD, color, redox potential, pH, and residual chlorine are stored in non-volatile memory.

The control unit 22, reading from the memory all the received data, sends them using the transmitter to a predetermined external device (for example, a computer).

The signal of the control unit 22 opens the solenoid valve 8 on the drain pipe 10 and empties all the cylinders. Then the valve 8 closes.

Compared with the prototype, the device according to the invention has the following advantages:

- the set of indicators characterizing the quality of natural and purified water is expanding;

- expanding the functionality of the device, providing a wide selection of measurement modes and the necessary accuracy.

The invention can be used to monitor water bodies, technical and drinking water supply.

The device may be a factory serial production.

LITERATURE

1. The method of sedimentation analysis of particles in a transparent dispersed medium. A.S. SU 1226174. Publ. 04/23/86. Bull. No. 15.

2. The method of sedimentation analysis of disperse systems. A.S. SU 1363020. Publ. 12/30/87. Bull number 48.

3. A device for analyzing water. Patent RU 2132049. Publ. 06/20/99. Bull number 17.

4. GOST R 52769-2007. WATER. Methods for determining color. Moscow. Standartinform. 2007.

5. The optical method for determining the chemical consumption of oxygen in natural waters. Patent RU 2087901. Publ. 08/20/97. Bull. No. 06.

6. Amperometric method for determining residual chlorine in water. Patent RU 2163375. Publ. 02/20/01. Bull. Number 07.

7.http: //www.msuee.ru/html2/med_gidr/13_4.html.

8. Vasiliev V.P. Analytical chemistry. In 2 book Prince 2: Physico-chemical methods of analysis: textbook. for stud. Universities studying chemical engineering. specialist. / V.P. Vasiliev. - 5th ed., Stereotype. - M .: Drofa, 2005. - 383, [1] p .: ill. (p. 179-181, 190-194).

9. Voznaja N.F. Water chemistry and microbiology: textbook. manual for universities / 2nd ed., revised. and add. - M .: Higher. School, 1979. - 340 p., ill. (p. 113-116).

10. http://www.izmteh.ru/catalog/el.php.

Claims (1)

A device for analyzing water, comprising a housing and a measuring cylinder located in it, a light source, at least three photodetectors that detect the light reflected by the particles of suspension, a photodetector that detects the light flux that has passed through the analyzed medium, a resistance thermometer, a water filling sensor, and input and output tubes with electromagnetic valves, two ring electrodes and a control unit, characterized in that it further comprises two measuring cylinders located in the same housing, in the lower part of which there are cups of high-precision scales, the housing additionally containing a measuring electrode of graphite, a comparative electrode of copper, an auxiliary electrode of stainless steel, a combined pH electrode and a combined redox electrode, and the light source is equipped with light filters with wavelengths of 380, 400, 410, 500 and 800 nm.

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