RU80006U1 - SENSITIVITY GAS SIGNAL - Google Patents

Abstract

The gas detector of increased sensitivity relates to measuring equipment - devices for analyzing gas in the environment, namely, to the device of gas analytical devices. It can be used to quantify the gas content in ambient air and to signal if its limit values are reached. The objective of the utility model is to increase the sensitivity of the determination of harmful substances. The technical result that can be obtained using the utility model is to drive into the gas detector a drive with a thermal element that creates a microconcentration of harmful substances for further analysis. The problem is achieved in that the gas detector of increased sensitivity contains a pneumatic pump, a multicapillary gas chromatographic column, a gas detector, a database of detected harmful substances, an information processing unit, an analog-to-digital converter, and indicators and signaling devices. At the same time, the device is characterized in that a drive is placed in it, located at the inlet of the multicapillary gas-chromatographic column in such a way that two parallel air branches are formed between its inlet and outlet of the air pump, one of which has a filter and a gas flow restrictor, and the other controlled throttle gas flow, and the outputs of the throttles through normally closed electro-pneumatic valves connected to the input of the drive, the output of which through a normally closed electro-pneumatic valve is connected to from polycapillary to the gas chromatographic column and a gas flow restrictor. Using the proposed gas detector can significantly increase its sensitivity in the analysis of gas flow from the environment, as well as analyze gas media containing a wide range of different compounds. The proposed gas detector has industrial applications in the chemical industry, in metallurgy and other industries. In addition, a gas detector can be used as an autonomous means of chemical control of air in industrial and other premises, at chemical weapons storage and destruction facilities, and mobile laboratories. 1 ill.

Description

The utility model relates to measuring technique - devices for analyzing gas in the environment, namely, to the device of gas-analytical devices. It can be used to quantify the gas content in ambient air and to signal if its limit values are reached.

Known gas analyzer (patent 2094794 from 09/27/1997, IPC G01N 27/407). It contains a voltage source, a solid electrolyte sensing element with electrodes and a heater connected to the output of the temperature controller, an amplifier, an indication unit and a multiplexer, it is also equipped with two adders, a division unit, a memory unit, a control unit and a linearization unit. The disadvantages of such a gas analyzer is its use only for the quantitative determination of one substance - fluorine.

Known gas analyzer (patent No. 2091781 from 09/27/1997, IPC G01N 27/00, G01N 27/12). It contains a sensor head including a sensing element, and a measuring circuit, a load resistor and power buses, and a measuring and signaling device comprising a measuring circuit, power buses, a current-voltage converter, and a compensating stage. This device was used in the development of gas analyzers for hydrogen sulfide 666 EC 15, 666 EC 16, sulfur dioxide, carbon monoxide, methane 604 EC 07, ammonia 342 EC 03, 342 EC 04, 342 EC 05, chlorine 662 EC 05. The disadvantages of such a gas analyzer is the low sensitivity of the detected substances.

The closest in technical essence and the achieved technical effect to the proposed technical solution is the "Gas analyzer" (RF patent for the invention No. 2209419, G01N 27/00). The gas analyzer contains the gas sensor itself, a flow restrictor, a gas flow inducer, an information processing unit, an analog-to-digital converter, a digital gas content indicator, a light alarm of the maximum contents, an audible buzzer of the maximum contents. The gas analyzer operates as follows. The ambient gas inlet flow is driven through the sensor itself.

a certain gas and a gas flow choke and is discharged by the effluent into the environment. The output of the gas sensor is fed to the information processing unit and, through an analog-to-digital converter, is fed to a digital gas content indicator, as well as to the signaling of the limit gas contents, light and sound. However, this gas analyzer is also characterized by a low sensitivity of the detected substances in ambient air.

The objective of the utility model is to increase the sensitivity of the determination of harmful substances.

The technical result that can be obtained using the utility model is to drive into the gas detector a drive with a thermal element that creates a microconcentration of harmful substances for further analysis.

The task is achieved in that the gas detector of increased sensitivity contains a pneumatic pump, a multicapillary gas chromatographic column, a gas detector, a database of detected harmful substances, an information processing unit, an analog-to-digital converter, and indicators and signaling devices. At the same time, the device is characterized in that a drive is placed in it, located at the inlet of the multicapillary gas-chromatographic column in such a way that two parallel air branches are formed between its inlet and outlet of the air pump, one of which has a filter and a gas flow restrictor, and the other controlled throttle gas flow, and the outputs of the throttles through normally closed electro-pneumatic valves connected to the input of the drive, the output of which through a normally closed electro-pneumatic valve is connected to from polycapillary to the gas chromatographic column and a gas flow restrictor.

The gas detector is shown in the figure,

where: 1 - pneumatic pump;

2 - filter;

3 - controlled throttle gas flow;

4 - throttle gas flow;

5, 6, 9 and 10 - electro-pneumatic valves;

7 - drive;

8 - thermo-heating element;

11 - multicapillary gas chromatographic column;

12 - gas detector;

13 - analog-to-digital Converter;

14 - the device database of the determined harmful substances;

15 - information processing device (microprocessor);

16 is a digital indicator of the content of the detected gas in the air;

17 - light alarm for the content of harmful gas;

18 - sound alarm content of harmful gas;

19 - timer.

The gas detector can be represented in the form of two blocks: measuring A and alarm B, as well as a pneumatic pump 1.

The measuring unit A is designed to transmit service information to the alarm unit B, which displays it.

Measuring unit A can be in the following modes:

- training mode;

- Work mode;

- diagnostic mode;

- training mode;

In the future, only the first two modes will be considered.

In the preparation mode, heating, temperature control of the units and adjustment of the parameters are performed.

In the operating mode, input, analysis and identification of the test air in accordance with the table of measured components and further signaling and indication of the parameters takes place.

The measuring unit A consists of a pump 1; filter 2; controlled throttle gas flow 3; throttle gas stream 4; electro-pneumatic valves 5, 6, 9 and 10, 7; drive 7 with thermal element 8; multicapillary gas chromatographic column 11; gas detector 12; analog-to-digital Converter 13 and the device database is defined harmful substances 14.

Alarm block B is designed for:

- output of light signals DANGER, READY, MALFUNCTION, and INPUT and NETWORK;

- issuing a sound signal;

- changes in the operating modes of the device;

- display the current operating mode of the device:

- output of the self-diagnosis malfunction code of the device;

- display of service information during the maintenance of the device;

- communication control with the measuring unit.

Signaling unit B consists of an information processing device (microprocessor) 15; digital indicator of the determined gas content in the air 16; hazardous gas warning light 17; sound alarm content of harmful gas 18 and the timer 19.

The device operates as follows.

The mode of preparation for work.

In preparation for operation, the ambient air through a pneumatic pump 1 is fed to a filter 2, where the ambient air is cleaned of various impurities and thereby a carrier gas is formed, which then subsequently flows to the throttle 4, into a multicapillary gas chromatographic column 11, a gas detector of type 12 ion mobility spectrometer and is released into the environment. In this case, the electro-pneumatic valves 5, 6, 9 and 10 are in the “closed” position.

The operation of the gas detector includes the accumulation of an air sample, thermal desorption and injection of the sample, analysis of the sample. Let's consider them in the indicated sequence.

The accumulation of air samples.

During the accumulation of the air sample, the electro-pneumatic valves 5 and 10 are in the “closed” position, and the electro-pneumatic valves 6 and 9 are in the “open” position.

The ambient air through a pneumatic pump 1 is fed to a controlled throttle 3, then through an electro-pneumatic valve 6 to a drive (concentrator) 7 with a sorbent TENAH 60/80 mehs and through an electro-pneumatic valve 10 is discharged into the environment. In this case, the sorbent located in the accumulator 7 absorbs harmful substances (compounds) contained in the air.

Upon completion of the accumulation of the air sample, the process of thermal desorption begins.

Thermal desorption and sample injection.

During thermal desorption of substances (compounds) from the sorbent of the accumulator, the electro-pneumatic valves 10 5, 6, 9 and 10 are in the “closed” position. By means of the thermo-heating element 8, the accumulator 8 and the predetermined temperature are heated. Then the electro-pneumatic valves 5 and 10 are transferred to the "open" position. By means of a throttle 4, a carrier gas is supplied to the accumulator 7, as a result of which harmful substances (compounds) desorbed from the sorbent of the accumulator 7 are supplied to the multicapillary gas chromatographic column 11, and then released into the environment through the gas detector 12. Upon completion of the supply to the multicapillary gas chromatographic column of 11 substances (compounds) desorbed from the sorbent of the storage medium, the electro-pneumatic valves 5 and 10 are put into the “closed” position.

Sample Analysis

The analysis of the sample is based on gas chromatographic separation of the analyzed sample of ambient air, subsequent ionization by a radioactive source of the sample and registration of the ion current. In this case, the substances (compounds) desorbed from the Tenax 60/80 mehs sorbent of the accumulator 7 enter the multicapillary gas chromatographic column 11, where the substances are separated in accordance with their nature. Then the signal is sequentially fed to a gas detector 12 of the type ion-mobility spectrometer.

In the sensor 12, the components of the input stream of the analyzed ambient air are recorded and identified in accordance with their nature. Next, the analog signal is amplified and converted to digital.

The output from the gas sensor 12 is fed to an analog-to-digital converter 13 simultaneously with information from the database of the detected harmful substances 14, where it is identified with the extracted components of the measured gas and compared with their maximum permissible concentrations. This difference characterizes not only the presence of a specific harmful substance in the air, but also the deviation of its concentration from the table value, i.e. absolute concentration of harmful substances.

Further, the final information is fed to the signaling unit B. In this case, through the information processing device (microprocessor) 15, the signal is transmitted to the digital gas content indicator 16, as well as to the signaling of the limit gas contents, light 17 and sound 18 with the simultaneous start of the timer 19.

Thus, the high sensitivity of the gas detector is achieved through the use of a drive with a thermal element, creating a microconcentration of harmful substances for its further analysis.

Further analysis of the sample of microconcentration of harmful substances is carried out using a multicapillary gas chromatographic column 5, in which the sample of the test medium is divided into components that allow recording and identifying the required components of the ambient air.

Each new measurement cycle begins with a sample input.

At the identification stage, in addition to the main program for identifying the substance and changing the signal DANGER, the degree of purity of the sensor 6 is analyzed. Depending on the results of the analysis, the cycle repeats with a satisfactory sensor purity. If there is contamination, the sample is not taken and the measuring unit is automatically cleaned. In operating mode, parameters that affect the operation of the unit are monitored and supported.

The use of the proposed gas detector can significantly increase its sensitivity in the analysis of gas flow from the environment, and also allows the analysis of gas media containing a wide range of different compounds.

The proposed gas detector has industrial applications in enterprises of the chemical and processing industries, in metallurgy, gallurgy and other industries. In addition, a gas detector can be used as an autonomous means of chemical control of air in industrial and other premises, at chemical weapons storage and destruction facilities, and mobile laboratories.

Claims (1)

A gas detector of increased sensitivity, consisting of a pneumatic pump, a multicapillary gas chromatographic column, a gas detector, a database of detected harmful substances, an information processing unit, an analog-to-digital converter, and indicating and signaling devices, characterized in that a storage device is added located at the input of the multicapillary gas chromatographic column so that between its inlet and outlet of the pneumatic pump two parallel air branches are formed, in one of which s is a filter choke and the gas stream, and the other - controlled throttle the gas flow, with the outputs through the normally closed throttle electropneumatic valves connected to the accumulator input, the output of which through normally closed electropneumatic connected with both of polycapillary column gas chromatograph and a gas flow restrictor.