RU2400745C2 - Airborne dust, vapour and gas detector - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: airborne dust, vapour and gas detector has a miniature case with a cover and a top panel moved through a slider. In the top part there is a socket for a piezoelectric sensor with a sensitive film coating for detecting air or dust components. Also inside the case under the panel with the piezoelectric sensor there is a miniature excitation circuit connected to a microprocessor for picking up and converting the piezoelectric sensor signal, transmitting it to a digital display and storing it in memory which is independently actuated by a power element built into the case or from an external source. In the bottom part of the case there are outputs for a charging device and connection with a computer for moving information from the memory. There is also a switching on button and a digital display for displaying the picked up signal on the one lateral surface of the miniature case.

EFFECT: mobility and compactness of the detector, possibility of using compact power sources with float time or using an external power source, rapid analysis of air or mixture of gases and dust, including in field conditions without sample collection and sample preparation, possibility of measuring dust level through fast replacement of piezoelectric sensors on the movable panel of the device, duration of preservation of operational characteristics with wide variation of properties of the analysed air, as well as possibility of storing information for transmitting measurement data through built-in memory and computer output.

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Description

The invention relates to techniques for the rapid analysis of air or gas mixtures, including for determining the concentrations of gases, vapors, dust in the air in off-laboratory conditions in the on-site mode.

Currently, the market for gas sensors and analyzers is represented by systems that differ in the nature of operation and operational characteristics. Fundamentally, they are divided into systems of continuous and periodic action. Continuous systems are small-sized, but, as a rule, highly selective for individual gases, and gas analyzers have restrictions on the group of determined air components, their scale is often graduated in units of concentration of one gas, for their stable operation certain initial conditions are needed (for purity or humidity, being in space or a power source, etc.).

The technical task of the invention is to develop a detector for detecting gas, vapors and dust in the air, which allows combining some characteristics of sensors and analyzers, such as: minimum dimensions, expressness of information, autonomy or multivariance of power, easy control and change of selectivity to detected gases, the ability dust level measurements, long-term maintenance of operational characteristics with a wide variation in the properties of the analyzed air environment, diagnostic capabilities Nia air in non-laboratory conditions in the "on the spot" preserving information for transferring the measurement data.

To solve the technical problem of the invention, there is provided a detector for detecting gas, vapors and dust in the air, which contains a miniature housing with a lid and a movable upper panel that extends using a slider, on which piezosensor sockets with a sensitive film coating are mounted in the upper part for detecting air components or dust, inside the case under the panel with a piezosensor there is a miniature excitation circuit connected to a microprocessor for recording, converting the signal of the piezosensor a, transferring it to a digital display and storing it in memory, driven independently from the built-in battery or from an external source, in the lower part of the case there are outputs for a charger and combined with a computer for transferring information from the memory, on one of the side the surfaces of the miniature housing are placed a power button, a digital display for displaying the recorded signal.

The technical result consists in the mobility and compactness of the detector with a minimum size while maintaining all operational functions (generating a piezosensor oscillation, autonomous or external power supply, recording, processing and storing information) through the use of a miniature microcircuit and a programmable microprocessor, the possibility of using compact power supplies with a reserve of time or using an external power source; in express obtaining the results of the analysis of air or mixtures of gases, dust, including in off-laboratory conditions without sampling and sample preparation (air diagnostics of rooms, work areas, analysis of the sample in the on-site mode); in easy control and change of selectivity to the detected gases, the possibility of measuring the dust level due to the quick change of piezosensors on the device’s sliding panel, which are the detector’s components; in the long-term maintenance of operational characteristics with a wide variation in the properties of the analyzed air environment due to the discrete measurement mode and termination of the piezosensor load by moving it into the housing after a certain contact time with the analyzed medium; the ability to save information for transferring measurement data due to the available built-in memory and access to a computer (adapter).

Figure 1 - The position of the slider "0":

a) general view of the detector; b) frontal section.

Figure 2 - Position of the slider "1":

a) general view of the detector; b) frontal section.

The detector for determining gas, vapors and dust in the air (D-1, FIGS. 1, 2) consists of a miniature housing 1 with a cover 2, with a movable upper panel 4, sliding out of the housing using the slider 3. On the upper surface of the movable panel 4 built-in sockets for the piezosensor 5, connected by elongated mounts 6 with a miniature excitation circuit 7 located inside the housing, by a microprocessor 8 for recording, converting the piezosensor signal, transmitting it to a digital display 9, storing in memory, replaceable batteries or other elements and power 10. On the side surface of the housing there is a digital display 9 for displaying the detected signal of the piezosensors, a light indicator of the device’s readiness for operation 11, the power button 12, the output 13 for the charger or the power supply and the output for combining with a computer are located at the bottom of the case fourteen.

The detector for determining gas, vapors and dust in the air works as follows.

Remove the cover 2 and slide the movable panel 4 of the detector from the housing 1 by setting the slider 3 in position "1" (figure 2). The slider is mounted on the side panel of a miniature, for example 5 × 3 × 1 cm, housing 1, the dimensions of which are determined by the dimensions of the built-in excitation block circuits and microcircuits, batteries. A piezosensor 5, for example, with a selective coating to phenolic compounds, is placed in slots on a movable panel. Through elongated fasteners (wires) 6, which ensure stable operation of the piezosensor in both positions of the sliding panel ("0" - Fig. 1 and "1" - Fig. 2), the piezosensor is connected to a miniature excitation circuit 7, with a microprocessor 8 for recording and converting the signal of the piezosensors and transmitting it to the digital display 9 (side surface of the housing), which are located inside the detector housing and are driven by replaceable batteries or other batteries 10. Autonomous power supplies can be charged if necessary (output 13).

After installing the piezosensor on the movable panel, the slider 3 is moved to the “0” position (FIG. 1), while the piezosensor is moved into the housing. The detector is turned on with button 12 (the indicator light 11 lights up), and the initial frequency of the piezosensor is displayed on the digital display 9.

Readiness for measurement is determined by the stability of the initial oscillation frequency of the piezosensor, the changes of which, depending on the nature of the film coating, should be no more than 3-7 Hz. Next, the corresponding gases (in the example, phenols) are detected in air. To do this, move the slider 3 to position "1" (figure 2) (the piezosensor moves from the housing to the test environment). Gases diffuse spontaneously to the surface of the film coating, interact with it for a certain time, which depends on the characteristics of the reaction between the gas and the film coating, while the frequency of the piezosensor changes and a decrease in the frequency on the display is observed. After a certain time, the slider is moved to the “0” position, the piezosensor moves into the housing, and the change in the oscillation frequency stops. The difference between the initial and steady-state values of the oscillation frequency of the piezosensor (ΔF, Hz), which is transferred to the memory, is calculated.

The concentration of detected gases and dust is determined by the equation of the calibration function for each piezosensor

ΔP = a · C _x + b,

where a is the sensitivity coefficient of the calibration function, b is the noise level - are individual for each piezosensor, are determined by the nature of the film coating, and are found by standard gas mixtures (characteristics attached to each piezosensor).

If there is no need for instant decision-making, then measurements are taken, and the results are entered into the detector short memory with subsequent transfer to a computer with a database and processing.

If a reversible reaction proceeds on the film coating, then for repeated use, the piezosensor is regenerated in a stream of dried air. Recovery is not required when an irreversible gas reaction occurs on the film coating (it is indicated how many measurements the piezosensor is designed for). To restore the performance of such elements, it is necessary to wash off the film coating from quartz and apply a new one or purchase a ready-made piezosensor.

The proposed miniature detector for determining gas, vapors and dust in the air (for determining the concentration of gases, vapors, dust) allows you to:

1) increase the mobility and compactness of the detector with a minimum size while maintaining all operational functions (generation of piezosensor oscillations, autonomous or external power supply, registration, processing and storage of information);

2) expressly receive information on the state of air and gases in real time without sampling and sample preparation;

3) to simplify the management and measurement of gas concentrations in the on-site mode;

4) quickly change the selectivity to the detected gases, the ability to measure dust level due to the rapid change of piezosensors on the sliding panel of the device;

5) expand the analytical capabilities of the miniature detector, including by eliminating the calibration of the device in units of one gas concentration, microprocessor converting the signals of the piezosensor (piezosensors) into a response and then finding the concentration according to the calibration graph, individual for each measuring element;

6) long-term maintain the operational characteristics of the device with a wide variation in the properties of the analyzed air environment;

7) diagnose air in off-laboratory conditions in the “on-site” mode with saving information for transferring measurement data due to the small size, available internal memory and access to a computer (adapter).

There are no analogues.

Claims (1)

The detector for detecting gases, vapors and dust in the air contains a miniature case with a lid and a movable top panel that extends with a slider and mounted on the top of which are mounted a piezosensor socket with a sensitive film coating for detecting air or dust components inside the case under the panel with a miniature excitation circuit connected to a microprocessor for recording, converting a piezosensor signal, transmitting it to a digital display and storing in memory is located by a piezosensor operating independently from a battery built into the case or from an external source, at the bottom of the case there are outputs for a charger and combining with a computer for transferring information from memory, on one of the side surfaces of the miniature case there is a power button, a digital display for reflecting signal.

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