RU2785604C1 - Method for monitoring the residual operating life of an insulating gas mask with chemically bonded oxygen and apparatus for implementation thereof - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: invention relates to measuring equipment intended for use in personal protective equipment for the respiratory organs, and is aimed at increasing the accuracy of determining the residual operating life of an insulating gas mask with chemically bonded oxygen. Proposed method for monitoring the residual operating life includes the stages of placing an impeller and a temperature sensor in the breath line near the front of the gas mask; continuously counting the number of revolutions of the impeller and measuring the temperature of the breathing mixture when passing through the impeller; calculating the volumetric flow rate of the breathing mixture passed through the impeller; calculating and indicating the residual operating life. The volumetric flow rate is calculated with account to the temperature measured, not including the revolutions of the impeller made automatically when the direction of movement of the breathing mixture is changed in the calculations. Prior to calculating the residual operating life, the breathing intensity is determined, and the resulting volumetric flow rate is reduced to the same level with the nominal limit value thereof, with account to the nonlinear dependence of the flow rate on the breathing intensity. The reduced flow rate is compared with the nominal limit value calculated from the mass of the chemical substance in the regenerative canister. Proposed is a constructive variant of execution of an apparatus for the implementation of the method, characterised by high compactness, convenience, and ease of installation in insulating gas masks of various designs.

EFFECT: higher accuracy of determining the residual operating life of an insulating gas mask.

10 cl, 10 dwg

Description

The field of technology to which the invention belongs

The invention relates to measuring equipment intended for use in personal respiratory protection equipment (PPE) with chemically bound oxygen.

State of the art

The composition of all insulating RPE (also known as: insulating gas mask, self-contained breathing apparatus, respirator and self-rescuer) with chemically bound oxygen includes: a regenerative cartridge with an oxygen supply source in the form of a regenerative product (chemical), a breathing bag to compensate for fluctuations in the breathing mixture when serving or consuming, a breathing hose (tube) and a front part, the execution of which can be different: mask, half mask, hood, mouthpiece, etc.

In the regenerative cartridge, the gas-air respiratory mixture (abbreviated as GDS) is regenerated due to the absorption of carbon dioxide and water vapor by the chemical substance from the exhaled GDS and the release of oxygen into it. The rate of consumption of a chemical in a regenerative cartridge depends on many factors, which makes it difficult to accurately determine the residual resource of the protective action of the insulating agent.

There is a known method for controlling the exhaustion of a regenerative cartridge, which consists in installing a gas meter impeller in a tube glued to the breathing bag at the place where the overpressure valve is installed, and measuring the released gas-air mixture (flow rate) until the established limit values are reached (see patent RU 2757981, IPC: А62В 7/08, published 10/25/2021).

The known method is based on the fact that the oncoming air flow, bled through the overpressure valve of the gas-air mixture, rotates the impeller, the angular velocity of which is proportional to the flow rate, and hence to the flow rate. By counting the number of revolutions of the impeller, the volume flow rate of the breathing mixture passing through the impeller is calculated, which is recorded on an accrual basis and compared with the maximum nominal volume value calculated from the mass of the chemical of the regenerative cartridge. When the flow rate reaches the limit value, the device emits a sound, light or other signal. In this case, it is assumed that the volumetric velocity of the gas-air mixture through the excess pressure valve will change in accordance with the intensity of the exhaled air regeneration process and the intensity of breathing.

A similar method for controlling the resource of a regenerative cartridge is used in devices according to patents SU 1789231, publ. 01/23/93 and SU 193932, publ. 03/13/67.

The disadvantages of this method include the low accuracy of readings of the residual resource, due to the fact that at low loads and low breathing intensity, there is often no excess pressure necessary to operate the valve, which means that the device does not record the flow rate. In addition, this method does not take into account the dependence of the volume flow on the temperature of the respiratory mixture and the loss in the path of the respiratory mixture.

There is a known method for assessing the residual life of RPE with chemically bound oxygen, implemented by the device according to patent RU 180899 U1, published on 06/19/2018, IPC: A62V 7/08. The method includes placing the flow meter in the breathing line between the heat exchanger and the cartridge, measuring the flow rate of the respiratory mixture, calculating the residual life of the RPE and visualizing it on the display of the device.

A significant disadvantage of this method is the use of a differential pressure sensor as a flow meter, which does not allow for high accuracy of readings in a wide range of breathing apparatus use intensity.

As a rule, all known pressure sensors are "tuned" to a narrow measurement range: either to perceive large pressure drops, or to work in conditions of small pressure jumps. It is almost impossible to set up a pressure sensor for measurements with high accuracy over a wide range.

Often this problem is solved by using a fixed flow rate at low intensity of use, for example, taken from regulatory documents, in the calculations. However, this leads to inaccurate results.

In addition, pressure sensors are sensitive to temperature and humidity, which leads to an increase in measurement errors, and also creates breathing resistance due to the use of flow constriction elements, which increases the burden on the user of the apparatus and contributes to an increase in the consumption of GDS. In some cases, to reduce the effects of resistance, a blower is installed in the breathing channel, but this complicates the design of the breathing apparatus and increases its weight, which also increases the load on the person.

As the closest analogue for the proposed method for controlling the residual resource of an insulating gas mask, a method implemented by means of a control device that is part of a respirator with chemically bound oxygen, a patent for an invention RU 2001645, IPC: A62B 7/08, publ. 12/24/1991. As proposed, the known method is implemented using an impeller placed in the path of the breathing mixture flow, and includes continuous counting of the number of revolutions of the impeller and calculation of the volume flow rate of the respiratory mixture passed through the impeller, calculation of the remaining resource by comparing the volume flow rate of the breathing mixture with the nominal limit value volume, calculated based on the mass of the chemical in the regenerative cartridge, and an indication of the remaining resource,

However, the known method does not take into account the fact that the flow meter with an impeller refers to volume flow meters and its readings depend significantly on the temperature of the respiratory mixture, which is not controlled in the known method, which leads to an error in the readings. In addition, placing the impeller at the outlet of the overpressure valve leads to measurement errors at light loads and low breathing rates.

A known device for evaluating the residual life of RPE with chemically bound oxygen, containing a constriction device built into the breathing line, a differential pressure sensor for measuring the pressure drop in the constriction device, a remote unit with a battery, a microcontroller for reading and processing data from the differential pressure sensor , and a display for displaying information about the residual life of the RPE (patent RU 180599 U1, IPC: А62В 7/08, publ. 06/19/2018).

A significant disadvantage of the known device is that it does not allow to determine the depletion of the resource with high accuracy in a wide range of RPE use intensity, which is due to the use of a pressure sensor. At the same time, as noted above, pressure sensors include flow constriction elements that create breathing resistance, which increases the load on the user and contributes to an increased consumption of GDS. In addition, pressure sensors contain semiconductor elements that are sensitive to temperature and moisture, the ingress of which is not excluded during breathing and can lead to a decrease in the sensitivity of the sensor and an increase in measurement errors.

As the closest analogue for the claimed device for monitoring the residual resource of an insulating gas mask with chemically bound oxygen, by the presence of similar design features, a device used to control the residual resource in a respirator with chemically bound oxygen, see patent for invention RU 2001645, IPC: A62B 7/08, publ. December 24, 1991

The known control device, as claimed, contains an impeller, a measuring circuit, a measurement results processing unit that calculates the volumetric flow rate of the respiratory mixture and determines the residual resource, the residual resource indicator unit associated with it, and a power source, without which the device cannot operate.

In the closest analogue, the impeller is installed at the outlet of the overpressure valve, which is the reason for the low sensitivity of the known device at low loads, and as a result, the low accuracy of residual resource readings.

The problem to be solved by the invention is the development of a method for monitoring the residual resource (protective action time) of an insulating gas mask with chemically bound oxygen, which provides high accuracy of readings under conditions of a wide range of respiratory intensity changes, as well as the creation of a simple and compact device that ensures the implementation of this method.

The technical result achieved by using the proposed invention is to increase the accuracy of determining the residual resource of an insulating gas mask under conditions of a wide range of changes in breathing intensity.

At the same time, the compactness of the device, the convenience and simplicity of its installation in RPE of various designs are ensured.

Disclosure of the essence of the invention

The solution to the above technical problem is achieved due to the fact that in the proposed method for monitoring the residual resource of an insulating gas mask with chemically bound oxygen, implemented using an impeller placed in the path of the respiratory mixture flow, including continuous counting of the impeller revolutions and calculation of the volume flow rate of the respiratory mixture passed through the impeller , calculating the residual resource by comparing the volumetric flow rate of the respiratory mixture with the nominal limit value of the volume, calculated based on the mass of the chemical in the regenerative cartridge of the gas mask, and indicating the residual resource, according to the claimed invention, the impeller is placed in the respiratory line between the respiratory hose and the front part of the gas mask and the temperature of the respiratory mixture is measured as it passes through the impeller, the calculation of the volumetric flow rate of the respiratory mixture is performed taking into account the measured temperature, while excluding the impeller revolutions made due to inertia when the direction of movement of the respiratory mixture is changed, the respiratory intensity is determined by preliminary calculations of the residual resource, and the calculation of the residual resource is carried out taking into account the nonlinear dependence of the flow rate on the respiratory intensity.

The solution to the mentioned technical problem is also achieved in the proposed device for monitoring the residual life of an insulating gas mask with chemically bound oxygen, containing a power source, an impeller, a measuring circuit, a measurement results processing unit that calculates the volumetric flow rate of the respiratory mixture and calculates the residual life, and an associated display unit residual resource. According to the claimed invention, the device is equipped with a thermistor placed together with an impeller in the breathing line between the breathing hose and the front part of the gas mask, the measuring circuit includes sensors that convert the speed of the impeller and the temperature of the respiratory mixture into electrical signals supplied to the measurement results processing unit, which is made in the form programmable logic controller that implements the algorithm for measuring the impeller speed and the temperature of the respiratory mixture and calculates the volumetric flow rate of the respiratory mixture, taking into account the measured temperature, the inertia of the impeller when changing the direction of movement of the respiratory mixture and the intensity of breathing, while the power source is connected to the controller and the measuring circuit through the activation unit .

Let us explain the terms and abbreviations used in the description.

GDS - gas-air (gas) respiratory mixture, it is also a respiratory mixture, a mixture of gases and water vapor used for breathing.

Nominal or nominal value - the maximum allowable, as a rule, the calculated value of the parameter. In the proposed solution, this is the maximum volume of gas-air breathing mixture that can be obtained from a chemical placed in a regenerative cartridge of an insulating gas mask.

Volumetric flow - the volume of a substance passing through a given section of the pipeline per unit of time.

Thermistor (aka thermistor) is a semiconductor resistor, the electrical resistance of which decreases or increases significantly with increasing temperature.

One significant difference between the proposed technical solution and the closest analogue is the placement of the impeller in the breathing line connecting the regenerative cartridge with the front part of the gas mask, directly at the front part (mask, mouthpiece, etc.), which allows you to take into account the entire volume of gas-air breathing mixture consumed for breathing .

At the same time, the impeller placed in the breathing line rotates freely in plain bearings, practically does not resist the air flow and does not create additional breathing load. In addition, unlike pressure sensors, the impeller is not affected by humidity and temperature.

Another significant difference is the continuous monitoring of the temperature of the breathing mixture passing through the impeller, the measurement data of which are used in the calculation of the flow rate, which allows taking into account the existing dependence of the GDS volumetric flow rate on temperature.

Calculation of the volumetric flow rate of the respiratory mixture is performed taking into account the measured temperature, while the impeller revolutions made by inertia when changing the direction of movement of the respiratory mixture between inhalation and exhalation are excluded from the calculations. Preliminary calculations of the residual resource determine the intensity of breathing, and the calculation of the value of the residual resource is carried out taking into account the non-linear dependence of the flow rate on the intensity of breathing.

Taken together, all the above-mentioned distinguishing features make it possible to achieve high accuracy of readings of the residual life of the insulating gas mask, the remaining time of its protective action, regardless of the intensity of use.

For temperature measurement, preferably a small thermistor is used, which is placed near the impeller in the breathing channel.

The execution of all operations of the method is ensured by using a digital computing device as a block for processing the measurement results, for example, a programmable logic controller that implements the measurement and calculation algorithm.

Readings from the sensors that convert the impeller speed and the temperature of the respiratory mixture into electrical signals are carried out at a fixed frequency, which for the impeller is at least three times the maximum respiratory rate, and for the temperature sensor - at least 10 times more often than readings from the impeller. In this case, the volume flow calculations use the average temperature determined over the period between readings from the impeller.

The respiration rate can be determined based on a moving average of several, eg, three or four, of the most recently calculated gas volume flow rates.

The indication of the remaining resource, expressed as a percentage, is carried out, preferably, by means of an LED scale consisting of colored elements, each of which corresponds to an equal percentage of the resource. In particular, it can be a line of LEDs, consisting of ten colored elements of red, yellow and green colors, each of which corresponds to 10% of the resource.

Preferably, all the constituent elements of the device are placed in a common housing, made with a tubular cavity for accommodating the impeller and thermistor, built into the breathing line between the breathing hose and the face of the gas mask. The remaining elements of the device: power supply, processing unit and display unit, are located outside the cavity. The housing may provide for the possibility of placing a heat exchanger and attaching a mouthpiece.

Such a device is highly compact and can be quite easily and simply built into the breathing line of an insulating gas mask of any design.

Due to the fact that the power source is connected to the controller and the measuring circuit through the activation unit, the possibility of discharging the power source during the storage of the gas mask is eliminated.

In a preferred embodiment, the activation block contains a reed switch and a magnet, between which is placed a metal curtain (check), which is removed before using the device.

A lithium cell can be used as a power source.

The essence of the proposed method is illustrated by the example of the operation of the device for monitoring the residual life of an insulating gas mask with chemically bound oxygen (hereinafter referred to as the control device), as well as drawings and other graphic materials, which show:

In FIG. 1 - an example of a general view of an insulating gas mask (self-rescuer) before and after embedding the proposed control device in its design;

In FIG. 2 - block diagram of the control device;

In FIG. 3 - a possible example of the design of the device housing, isometry, longitudinal section;

In FIG. 4 example of execution of the block of sensitive elements;

In FIG. 5 - circuit for converting the resistance of the thermistor into an electrical signal;

In FIG. 6 - device activation block;

In FIG. 7 simplified structure of the microcontroller operation algorithm;

In FIG. 8 - a fragment of the code of the algorithm for cutting off the inertial rotation of the impeller;

In FIG. 9 - an example of the operation of the algorithm for cutting off the inertial rotation of the impeller;

In FIG. 10 is a graph of the dependence of the life of the self-rescuer on the load (intensity of use), demonstrating the nonlinearity of this dependence.

For miners whose work is carried out in an environment with a possible dangerous concentration of gases, simplified insulating gas masks of reduced weight and with a mouthpiece instead of a mask, the so-called mine self-rescuers (hereinafter self-rescuer), have been developed. Like any other insulating gas mask, the self-rescuer (SS) includes, see Fig. 1: regenerating cartridge (a) with chemical supply, breathing bag (b), breathing hose (c) and front part (d), consisting in the case of a self-rescuer of a mouthpiece and goggles.

The nominal operating time in such a self-rescuer, calculated for normal conditions, is from 30 to 60 minutes, depending on the model. In real conditions of use, the time of the protective action of the self-rescuer can vary significantly. It is known that the range of GDS flow rate, depending on the worker's breathing intensity, ranges from 10 l/min in quiet mode to 70 l/min when a person is running. In this regard, it is important to accurately understand the remaining time of the protective action of the self-rescuer, which is necessary to be able to make the right decision to leave the danger zone. For these purposes, the proposed control device 1 (see Fig. 1) can be built into the self-rescuer.

In FIG. 2 shows a block diagram of the proposed device for monitoring the residual life of an insulating gas mask. The control device 1 includes the following functional blocks: a block 2 of sensitive elements located in the respiratory line L, designed to measure the parameters of the flow of the respiratory mixture, a measuring circuit 3, a programmable logic microcontroller 4 that implements the measurement and calculation algorithm, a display unit 5, a power source 6, for example lithium cell, and activation unit 7.

Block 2 consists of two sensitive elements: impeller 8 for measuring the flow rate and a small-sized thermistor 9 for measuring the flow temperature.

The power supply 6 is designed to provide the electronic circuit with electrical energy with the required parameters. Between the power supply 6 and the microcontroller 4, a reference voltage source (ION) 10 is installed to convert the initial voltage of the source 6 into a stabilized voltage of the required value, which is necessary for the correct operation of the analog part used to measure temperature.

All blocks are placed in a common housing 11 (see Fig. 3), made with an internal tubular cavity 12 to accommodate the impeller and thermistor (block 2) and a window 13, behind which is placed the display block 5. With the exception of block 2, all other constituent elements control devices are placed on the outer side of the cavity 12.

On the one hand, a breathing hose (c) is connected to the housing 11, and on the other hand, a mouthpiece 14, while the housing provides a place 15 for a heat exchanger, usually located at the inlet of the front part.

As can be seen from the above examples, the control device 1 is very compact and can be easily and simply integrated into the breathing line of insulating gas masks of various models, regardless of their design. In this case, the cavity 12 of the body 11 forms a section of the respiratory line L, along which the respiratory mixture moves.

An example of execution of block 2 is shown in Fig. 4. The axis of the impeller 8 is mounted on plain bearings, which ensures minimal friction losses and high sensitivity even to small GDS flows. Thermistor 9, due to its small size, provides a high speed response to temperature changes. The sensing elements are installed in close proximity to each other in order to bring the volume flow to the nominal temperature with maximum accuracy.

Measuring circuit 3 consists of two functional units that convert the rotation of the impeller 8 into an electrical signal and convert the resistance of the thermistor 9 into an electrical signal.

The unit for converting the rotation of the impeller 8 into an electrical signal can be made in the form of a photoelectric sensor, including an emitting LED and a receiving photodiode located opposite each other in the same plane with the axis of the impeller 8 and parallel to it. The flow of the respiratory mixture passing through block 2 causes the impeller 8 to rotate. When the impeller rotates, its blades periodically block the infrared radiation beam created by the LED. The photodiode detects intermittent radiation and converts it into an electrical signal, the frequency of which is proportional to the speed of rotation of the impeller 8. This signal is fed to the output of the microcontroller 4 for further processing.

The unit for converting the resistance of the thermistor 9 into an electrical signal can be made on the basis of a voltage divider R1 and R2 (see Fig. 5). The divider is connected to a source of stabilized voltage (+ U _stab ). The thermistor R2 is included in the lower arm of the divider, from which an electrical signal proportional to the temperature of the breathing mixture is taken. The received signal is fed to the non-inverting input of the operational amplifier DA1, which is connected according to the voltage follower circuit. The output signal of the operational amplifier passes through a low-pass filter (R4 and C1) and is fed to the output of the microcontroller 4 for further processing.

The display unit 5 in the example shown includes ten colored LEDs: two red, three yellow and five green, located on the printed circuit board with a certain pitch, so that a visual scale is formed. Each LED corresponds to 10% of the life of the self-rescuer. The scale displays the residual life of the self-rescuer in percent.

The device works as follows.

When the self-rescuer is opened and the lid is thrown off, the self-rescuer starting device (not shown in the drawings) and the activation unit 7 of the control device 1 are automatically activated, which connects the power source 6 to the electronic circuit of the device.

The activation block 7 preferably includes a reed switch 16 and a magnet 17 separated by a metal shutter 18 (check) (see Fig. 6). The reed switch 16 is installed on the printed circuit board 19, and the magnet 17 is glued into the body 11 of the device. Between the magnet 17 and the reed switch 16 in the housing 11 there is a small cavity 20, into which a shutter 18 is inserted, blocking the magnetic field from the magnet to the reed switch.

During the entire time of storage of the SSH, the shutter 18 is in the cavity 20, the magnetic field is blocked, the reed switch 16 is open. all elements of the schema.

After the power is connected, the microcontroller 4 initializes the internal periphery and associated blocks - the display unit 5 and the measuring circuit 3, after which it proceeds to execute the program recorded in it.

The main program loop consists of several subroutines, including:

- a subroutine for measuring the speed of the impeller and the voltage on the thermistor;

- a subroutine for calculating the volume and temperature of the GDS that has passed through the impeller;

- a subroutine for calculating the residual life of the self-rescuer;

- a subroutine for indicating the percentage of the remaining resource on the LED scale.

In FIG. 7 shows a simplified structure of the microcontroller 4 software operation algorithm.

The rotation of the impeller 8 and the voltage across the thermistor 9 are measured, for example, as follows. The angular velocity of the impeller 8 is directly proportional to the GDS flow rate. The revolutions of the impeller 8, converted by the photoelectric sensor into pulses, are fed to the input of the microcontroller 4. The microcontroller integrates the fixed pulses every 250 ms and writes the obtained value to the variable n _i .

Since the GDS flow is constantly changing direction, and the impeller 8 has inertia, it must be taken into account, otherwise the linearity of the sensor will be lost. To track the inertial rotation of the impeller, each new value of n _i is compared with a variable that stores the maximum value of the impulses n _{i max} .

If the value of n _i is greater than n _{i max} , then the value of n _i is assigned to the variable n _{i max} . Otherwise, the variable n _i is compared with the value 0.5 ⋅ n _{i max} , and when the value n _i is less than 0.5 ⋅ n _{i max} , the program considers that the impeller 8 rotates by inertia for some time, therefore, the value n _i is excluded from the calculations . To include n _i back into the calculation, the program compares the value of the variable n _i with the previous value (n _ilast ) multiplied by 1.33.

If the value in the variable n _i exceeds its previous value by 1.33 times or more, then the program includes the variable n _i in the calculation, otherwise the variable is not taken into account in the calculation. In FIG. 8 shows a code fragment responsible for determining the inertia of the impeller. On the graph of Fig. 9, which illustrates an example of the operation of the algorithm described above, the solid line shows the value of the variable (n _i ) recorded every 250 ms, and the markers in the form of a circle 21 highlight the samples of the variable (n _i ) that are involved in the calculation.

In parallel with the measurement of the revolutions of the impeller 8, the voltage on the thermistor 9 is measured, which varies in proportion to the temperature of the HDS flow passing through the impeller. Voltage measurement is carried out at the hardware level by an internal ten-bit analog-to-digital converter (hereinafter - ACC) of the microcontroller 4.

Upon completion of the conversion, the subroutine, for the convenience of maintaining the firmware, converts the ADC units to millivolts according to the formula:

where: U _Rt - voltage on the thermistor, mV;

ADC _t - integer conversion result, conventional units;

U _rvf - reference voltage of the analog-to-digital converter.

After converting arbitrary units to voltage, the subroutine sets a flag that allows temperature calculation. The temperature calculation for the used thermistor is performed using the formula:

where: t° _HDS - temperature of HDS, °С; U _Rt - voltage on the thermistor, mV.

The resulting temperature value is written to an array that stores the last ten temperature values, from which its average value is then calculated.

The voltage measurement on the thermistor 9 is carried out at least ten times more often than the measurement of the number of revolutions of the impeller 8, and in the given example is performed every 25 ms, which makes it possible to take into account the rapid change in the temperature of the GDS flow over a wide range.

The measurement of the impeller revolutions lasts 250 ms, ten temperature measurements are made during this time. temperature at which calculations are performed. The volume flow calculation is performed whenever the inertia cutoff algorithm (FIGS. 8 and 9) sets the xCalculAllowedVol flag to a logical one, which includes the variable n _i in the calculation.

Calculation of the volumetric flow rate of the respiratory mixture is carried out taking into account the average temperature of the GDS, the calculations are carried out according to the formula:

where: V _iGDS - the volume of GDS that passed through the impeller in one measurement (250 ms), dm ³ ;

n _i - number of pulses of the impeller for 250 ms;

- коэффициент тарировки, учитывающий то, что дыхательная смесь проходит через крыльчатку на вдохе и выходе, и подбираемый индивидуально для каждой крыльчатки;

- calibration coefficient, which takes into account the fact that the respiratory mixture passes through the impeller on inhalation and exit, and is selected individually for each impeller;

- среднее значение температуры ГДС за одно измерение (250 мс),°С.

- average value of GDS temperature for one measurement (250 ms), °C.

The calculation of the residual resource of the protective action of the self-rescuer (insulating gas mask) is performed taking into account the intensity of its use in the period between measurements.

The nominal limit value of the volume of the breathing mixture is accepted and calculated from the operating conditions of the self-rescuer under moderate load, which, according to the regulatory documents (GOST 12.4.292-2015), is 60 min.

According to the same GOST, the operating time of a self-rescuer, for example, a self-rescuer of the XK type, at light loads and relative rest increases relative to the nominal by 3 times, and at heavy loads it decreases by 3 times, which implies that in the relative rest mode, the operating time will be 300% ⋅ 60 min = 180 minutes; in moderate mode: 100% ⋅ 60 min = 60 minutes;

and in heavy load mode: 30% ⋅ 60 min = 18 minutes.

Knowing the operating time and pulmonary ventilation in each mode, it is possible to calculate the nominal design life of the self-rescuer for different loads.

For the relative rest mode, it will be 180 min ⋅ 10 dm ³ / min = 1800 dm ³ ;

For moderate mode: 60 min ⋅ 35 dm ³ / min = 2100 dm ³ ;

For a heavy load mode, this volume will be 18 min ⋅ 70 dm ³ /min = 1260 dm ³ .

According to the specified points, a graph of the dependence of the life of the self-rescuer on the load is built. This dependence is non-linear (see Fig. 10), which makes it difficult to determine the remaining resource of the self-rescuer with mixed (real) breathing.

In order to determine the residual life of the self-rescuer at any time, regardless of the operating mode, the resulting value of the volume flow is brought to the same level with the nominal limit value by multiplying by a weighting factor that takes into account the non-linearity of the life of the self-rescuer in different modes.

In the device program, the algorithm described above is implemented as follows. Every four measurements V _{i of the HDS} are summed up, and the volume V _{sec of the HDS} passed through the device in 1 second (4 measurements in 250 ms) is obtained.

According to the value of the volume V _{sec of the GDS} , the intensity of breathing in the self-rescuer is judged and it is used to calculate the weighting coefficient, carried out according to the formula:

where R _secGDS - volume of GDS passed through the impeller in 1 second, dm ³ ;

a ₁ ... a ₄ - polynomial coefficients;

k _p is a weighting factor that takes into account the magnitude of the deviation from the linearity of the life of the self-rescuer, depending on the intensity of breathing.

Taking into account the weighting coefficient k _p, the volume V _seGDS measured in one second is added to the volume for all previous measurements.

where: _Vtot is the total volume of the GDS, measured for the entire time of operation of the self-rescuer, taking into account the weighting factor, dm ³ .

The remaining resource is calculated every second by the formula:

where:

HRM _% - the remaining time of the protective action of the self-rescuer, expressed as a percentage;

V _total - the total volume of the GDS, measured for the entire time of operation of the self-rescuer, taking into account the weighting factors, dm ³ .

Indication of the residual resource of the protective action of the self-rescuer is carried out using an LED scale consisting of ten colored elements (LEDs) 22 of red, yellow and green colors, each of which corresponds to 10% of the resource of the self-rescuer (block 5 in Fig. 2). When the device is turned on, the scale is fully lit, which corresponds to 100% of the remaining resource of the self-rescuer. In the process of breathing, the LEDs turn off in turn, which indicates the expenditure of the resource of the self-rescuer. When the entire resource of the self-rescuer is used up, all elements of the 22 scale will go out.

The measurement of GDS consumption and the calculation of the residual resource are repeated many times, without pauses, during the entire time of operation of the insulating gas mask.

The proposed device provides high accuracy of indications of the residual life of an insulating gas mask in a wide range of intensity of its use, which was confirmed by testing prototypes of the device, carried out on artificial lung ventilation units.

The proposed technical solution can be used in insulating gas masks with different schemes for the movement of the respiratory mixture, with appropriate software adjustments.

Claims (10)

1. A method for monitoring the residual resource of an insulating gas mask with chemically bound oxygen, implemented using an impeller placed in the path of the respiratory mixture flow, including continuous counting of the impeller revolutions and calculation of the volume flow rate of the respiratory mixture passed through the impeller, calculation of the residual resource by comparing the volume flow rate breathing mixture with a nominal limit value of the volume, calculated based on the mass of the chemical in the regenerative gas mask cartridge, and an indication of the residual life, characterized in that the impeller is placed in the breathing line between the breathing hose and the front part of the gas mask and the temperature of the breathing mixture is measured as it passes through impeller, the calculation of the volumetric flow rate of the respiratory mixture is performed taking into account the measured temperature, while the calculations exclude the revolutions of the impeller made by inertia when changing the direction of movement of the respiratory mixture, before Calculation of the residual resource is used to determine the intensity of respiration, and the calculation of the value of the residual resource is carried out taking into account the non-linear dependence of the flow rate on the intensity of respiration. 2. The method according to claim 1, characterized in that the readings from the sensors that convert the impeller speed and the temperature of the respiratory mixture into electrical signals are carried out at a fixed frequency, which for the impeller is at least three times the maximum respiratory rate, and for the temperature sensor - at least than ten times more frequent readings of the impeller, while the volume flow calculations use the average temperature determined between the readings of the impeller. 3. The method according to claim 1, characterized in that the respiratory rate is determined based on the moving average for the last few calculated values of the volumetric flow rate of the respiratory mixture. 4. The method according to p. 1, characterized in that the indication of the residual resource is carried out as a percentage by means of an LED scale consisting of colored elements, each of which corresponds to an equal percentage of the resource. 5. A device for monitoring the residual life of an insulating gas mask with chemically bound oxygen, containing a power source, an impeller, a measuring circuit, a measurement results processing unit that calculates the volumetric flow rate of the respiratory mixture and calculates the residual resource, and an associated residual resource indication unit, characterized in that that it is equipped with a thermistor placed together with an impeller in the breathing line between the breathing hose and the front part of the gas mask, the measuring circuit includes sensors that convert the speed of the impeller and the temperature of the respiratory mixture into electrical signals supplied to the measurement results processing unit, which is made in the form of a programmable logic controller , which implements the algorithm for measuring the impeller speed and the temperature of the respiratory mixture and calculates the volumetric flow rate of the respiratory mixture, taking into account the measured temperature, the inertia of the impeller when changing the direction of movement of the respiratory gas mixture and intensity of breathing, while the power source is connected to the controller and the measuring circuit through the activation unit. 6. The device according to claim 5, characterized in that all its constituent elements are placed in a common housing, made with an internal tubular cavity for placing the impeller and thermistor, built into the breathing line between the breathing hose and the front part of the gas mask. 7. The device according to claim 6, characterized in that the case provides for the possibility of placing a heat exchanger. 8. The device according to claim 5, characterized in that the display unit is made in the form of a line of LEDs, consisting of ten colored elements of red, yellow and green colors, each of which corresponds to 10% of the resource. 9. The device according to claim 5, characterized in that the activation unit includes a reed switch, a magnet and a metal shutter placed between them, which is removed before using the device. 10. The device according to claim 5, characterized in that a lithium cell is used as a power source.

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