RU71165U1 - WIDE-BAND OZONE CONCENTRATION METER - Google Patents

Abstract

The utility model relates to devices designed to measure the concentration of ozone in a gas environment, and can be used in medicine, as well as in other areas of technology where measurement of ozone concentration is required. The technical problem is to ensure accurate and stable operation of the meter when measuring in a wide range of values of ozone concentration. The solution of the technical problem is achieved by the fact that in the ozone concentration meter, consisting of an ultraviolet lamp, a cuvette with a flow distributor, a measuring and reference photodetectors, a microprocessor control unit and an indicator, one or more cuvettes of different lengths with flow distributors and measuring and reference photodetectors are introduced, connected to the inputs of amplifiers, the outputs of which are connected to an analog-to-digital converter built into the microprocessor microcontroller control unit. In this design, each cuvette operates in its optimal range of ozone concentrations, which ensures accurate and stable measurements. And thanks to the use of several cuvettes of different lengths, measurements are provided in a wide range of concentrations. P. F-ly, 1 ill.

Description

The utility model relates to devices designed to measure the concentration of ozone in a gas environment, and can be used in medicine, as well as in other areas of technology where measurement of ozone concentration is required.

The ozone concentration meter belongs to a common class of optical ozone meters, the principle of operation of which is based on the absorption of ultraviolet radiation with a wavelength of 253.7 nm by ozone.

A well-known two-channel optical meter of ozone concentration, consisting of an ultraviolet lamp, a cuvette, a measuring and reference photodetectors, a microprocessor control unit and a display that shows the measurement results (Universal medical ozone therapy apparatus "Ozone UM-80", operating manual and passport, Kharkov, Institute of Ozone Therapy and Medical Equipment, 2003, p. 12). In this meter, to compensate for the instability of the lamp, a reference channel is introduced containing a separate reference photodetector. The photodetector of the reference channel is located on the reverse side of the ultraviolet lamp and ultraviolet radiation enters it directly without a cuvette. By comparing the readings of the photodetectors of the reference and measuring channels, it is possible to compensate for the instability of the discharge lamp.

However, a gas-discharge ultraviolet lamp also has a spatial instability of radiation, which leads to instability of the meter readings.

An optical ozone concentration meter is also known, consisting of an ultraviolet lamp, a cuvette, a measuring and reference photodetector, a flow distributor, a microprocessor control unit and a display, which shows the measurement results (RF patent No. 60726 of July 26, 2006).

In this meter, to eliminate the influence of temporary and spatial instability of burning of an ultraviolet lamp, a special

ultraviolet flux distributor. Thanks to this design, it is possible to achieve high accuracy and stability of the ozone concentration meter.

However, sometimes the task arises of measuring ozone concentration over a wide range. In particular, when using medical ozonizers, it is necessary to measure the concentration of ozone in the range of 0.2 ... 100 mg / l. Using a single cell meter for such a wide range is problematic. With an optimum of measurements in one band, the useful signal at the output of the measuring photodetector in the other band becomes too small and commensurate with the noise and fluctuations of the signal, as a result of which the measurement becomes problematic. The situation is even worse due to the non-linearity of the measuring path. So, when testing the meter in the range of ozone concentrations of 1 ... 10 mg / l (i.e., when the concentration changes by a factor of 10), the useful signal changed by approximately 60 times, i.e. required a significantly larger range of the useful signal.

For measurements in a wide range, you can use several instruments designed to operate each in its own range, but this is associated with large overall dimensions and financial costs.

The technical problem is to ensure accurate and stable operation of the meter when measuring in a wide range of values of ozone concentration.

The solution of the technical problem is achieved by the fact that in the ozone concentration meter, consisting of an ultraviolet lamp, a cuvette with a flow distributor, a measuring and reference photodetectors, a microprocessor control unit and an indicator, one or more cuvettes of different lengths with flow distributors and measuring and reference photodetectors are introduced, connected to the inputs of amplifiers, the outputs of which are connected to an analog-to-digital converter built into the microprocessor microcontroller Lok management.

Figure 1 shows a diagram of the proposed wide-range meter of ozone concentration with two cuvettes.

A wide-range ozone concentration meter consists of a gas discharge ultraviolet lamp 1, a cell of different lengths with flow distributors 2 and 3, photodetectors for measuring channels 4 and 5, photodetectors for reference channels 6 and 7, a microprocessor control unit 8 and indicator 9. Photodetectors are connected to the inputs of amplifiers 10. The outputs of the amplifiers 10 are connected to the inputs of an analog-to-digital converter (not shown) built into the microcontroller

11 microprocessor control unit. An indicator 9 is connected to the microcontroller 11 of the microprocessor control unit.

Amplifiers 10 are designed to amplify analog signals to a level optimal for the operation of an analog-to-digital converter.

All cuvettes have different lengths. The length of each cuvette is selected optimal for operation in any one narrow range of ozone concentrations. For small concentrations of ozone the cell should be long, for large concentrations - short. The ranges of ozone concentrations in which the cuvettes work are selected so as to provide a slight overlap. For example, one cuvette covers the range of 0.8 ... 12 mg / l, the second - 8 ... 100 mg / l.

To simplify the design of cuvettes of different lengths can be made in the form of a single structural unit.

The ozone concentration meter operates as follows.

During operation of the ultraviolet lamp 1, the radiation enters all photodetectors. When the ozone-oxygen mixture passes through the cells, the signals of the measuring photodetectors 4 and 5 are attenuated. The signals from the photodetectors after the amplifiers 10 are fed to the inputs of an analog-to-digital converter built into the microcontroller 11 of the microprocessor control unit.

The microcontroller 11 starts the analysis of the signals with the longest cuvette 3, designed for low concentrations. If the signals from photodetectors 5 and 7 correspond to the operating range of this cell, then microcontroller 11 calculates the ozone concentration and displays the results on indicator 9. If the signals from photodetectors 5 and 7 exceed the operating range of this cell, then microcontroller 11 starts processing signals from photodetectors 4 and 6 of the next shorter cell 2, designed for large concentrations of ozone. By analyzing in this way the signals from photodetectors 4, 5, 6, and 7, microcontroller 11 ultimately selects a cell that is optimal for a given ozone concentration, calculates the ozone concentration, and displays it on indicator 9.

Thus, to measure each concentration value, the optimal cuvette is selected, as a result of which accurate and stable measurements are ensured. And thanks to the use of several cuvettes of different lengths, measurements are provided in a wide range of concentrations.

In accordance with the proposed technical solution, a prototype of a wide-range meter was manufactured and tested at Lepse OJSC

ozone concentration. It used two cuvettes 2 mm and 20 mm long. A cuvette of 2 mm is intended for the range of 10 ... 100 mg / l, a cuvette of 20 mm is intended for the range of 1 ... 10 mg / l. The readings of the prototype of the meter were compared with the reference meter “Cyclone 5.11”. The test results are presented in table No. 1.

Table number 1 Ozone concentration meter The concentration of ozone, mg / l Cyclone 5.11 0.7 0.9 1.4 2.0 2.9 4.0 6.1 7.7 Experience. sample 0.79 0.96 1.48 2.11 3.0 4.0 6.13 7.9 Error δ,% +12.8 +6.7 +5.7 +5.5 +3.4 0 +0.5 2.6 Cyclone 5.11 9,4 14.9 20.6 29.9 52.1 73.8 86.5 Experience. sample 9.7 15.7 20.6 30.9 53.6 75,5 89.0 Error 5% +3.2 +5.4 0 +3.4 +2.9 +2.3 +2.9

Here the designation is introduced: 5 - deviation of the measurement result from the readings of the reference meter "Cyclone 5.11" in percent.

The test results showed good agreement between the readings of the prototype of the ozone concentration meter with a reference meter. The measurement error in the range of 1 ... 100 mg / l did not exceed 7%. A slightly increased error is obtained when measuring a small concentration (near 1.0 mg / l), but this error is associated with an increased measurement error of the Cyclone 5.11 reference meter itself. So, for example, when measuring a concentration of 1.0 mg / l, only the error of the unit of the least significant digit of the reference meter gives an error of 10%.

The warm-up time of the proposed meter was small - 5 minutes. This is a significant advantage of the proposed meter, because in known meters, for example, Cyclone 5-11, the warm-up time reaches a value of about one hour.

Thus, the test results showed high accuracy and stability of the proposed meter when working in a wide range of ozone concentrations. The technical task is solved.

Claims (1)

An ozone concentration meter consisting of an ultraviolet lamp, a cuvette with a flow distributor, a measuring and reference photodetector, a microprocessor control unit and an indicator, characterized in that one or more cuvettes of different lengths with flow distributors and measuring and reference photodetectors connected to the amplifiers inputs are introduced the outputs of which are connected to an analog-to-digital converter built into the microcontroller of the microprocessor control unit.