RU235297U1 - Device for forced supply of purified air to respiratory protection equipment - Google Patents

Abstract

The utility model relates to the field of life safety. A device for forced supply of purified air to a respiratory protective device comprises a housing, in the cavity of which an impeller is placed, driven into rotation by a DC electric motor, and an autonomous power supply unit connected to the electric motor and a button for switching on the latter, wherein three gas mask filters are fixed on the outer side of the housing, each of which is in communication with the cavity of the housing, as well as a branch pipe for connecting a hose, the other end of which is in communication with the internal volume of the respiratory protective device, wherein the impeller is mounted pivotally on an axis in bearings and is placed in a casing placed in the housing and made with a branch pipe brought out of the housing through an opening, and with a central opening on one side of the casing, communicated with the cavity of the housing, and the DC electric motor is made of a brushless inverter with control from a controller with feedback, connected to the button for adjusting the power of the electric motor, and is placed autonomously on the other side of the casing wall, and the impeller is made with elements that have the ability to be captured by a magnetic field created by the electric motor when rotation of the rotor, wherein the controller of the DC electric motor is designed with the function of multiple increase of the rotation speed with each pressing of the button. The technical result consists in increasing the safety of using a multi-filter device for cleaning contaminated air due to the elimination of the design limiting high volumes of supply of cleaned air into the sub-mask space. 1 sec. f-ly, 4 fig.

Description

The utility model relates to the field of medicine, as well as to the field of life safety, namely to devices for processing and supplying air in order to ensure protection of the respiratory organs and vision from dust, harmful impurities, viruses and pathogens, as well as to facilitate breathing and improve the general physiological condition of a person.

A device for forced supply of purified air to a respiratory protective device is known, comprising a housing, in the cavity of which an impeller is placed, driven into rotation by an electric motor, and an autonomous power supply unit connected to the electric motor and a button for turning on the latter, while two gas mask filters are fixed on the outer side of the housing, each communicating with the cavity of the housing, as well as a branch pipe for connecting a hose to the housing, the other end of which is communicated with the internal volume of the respiratory protective device (RU 201261, A61L 9/20, published 07.12.2020).

This decision was adopted as a prototype.

This device has two brackets on the body, allowing the device to be attached to the user's belt.

The peculiarity of this device is that the purified air enters the under-mask space in a forced mode, i.e. under excess pressure, which is higher than atmospheric. This allows the use of loose-fitting masks or hoods. The high-pressure zone under the mask does not allow air from the environment with a pressure lower than the pressure under the mask to enter. Another peculiarity of the known solution is that the user does not drive the purified air through gas mask filters due to his own breathing/suction, which makes the user's breathing comfortable without overloading the lungs.

However, this solution has some drawbacks that reduce the operational reliability of the device and the safety of its use in conditions of medium and high severity of work.

The design of the device is such that the impeller sits on the shaft of the electric motor, which positions it. The impeller does not belong to the category of products of high manufacturing precision and its balancing. When rotating, the presence of even a small imbalance leads to a variable load on the motor shaft and on the supports of this shaft. The practice of using even high-precision fans shows that over time, noise begins, caused by the beating of the impeller on the shaft (evidence of the beginning of the loss of operability of the fan). The electric motor is overloaded and begins to slow down. In this mode, wear particles, abrasive are deposited in the area around the electric motor and impeller, and an unpleasant burnt smell appears, which then gets into the under-mask space. These indicators indicate a design malfunction of the device, which can end in a breakdown when the worker is in a zone dangerous for breathing.

The claimed solution uses two gas mask filters, which reduces the throughput load for transferring purified air into the under-mask space, since each filter operates in the area of free (uninhibited) air flow, i.e. with minimal or low resistance. With an increase in the volume of purified air, filters designed to pass air from the suction pressure of human lungs begin to limit the volume of purified air flow, since resistance increases. When using forced air pumping, such filters do not cope with the work of increasing the air entering the under-mask space. The filter mass in the filter works as a material of constant resistance to air flow. With an increase in the pumping speed, both in gas masks and respirators, the permeability coefficient decreases. For example, the air purification speed of a filter box is at least 30 l/min.

In reality, there are no universal gas mask filters. There are filters, the design of which is designed to disinfect certain types of contaminants. Therefore, using two filters with different cleaning capabilities for different types of contaminants is a good solution, since sometimes it is not possible to accurately determine the type of contaminant right away.

Practical conditions for using filters often differ significantly from laboratory conditions. The main parameters that affect the service life of a filter are listed below: the amount of inhaled air; the concentration of harmful substances; relative humidity; the type of harmful substance; filter capacity; atmospheric pressure. Most gas mask filters are used only to protect against gases/vapors that have clearly defined identifying characteristics - the ability to determine the presence of gases/vapors by smell/taste at a concentration in the air of up to 1 MAC. And the most common way to determine the time to change a gas mask filter is the appearance of a chemical smell/taste during work.

The number of filters also determines the user's ability to perform a particular job. For light work, one filter with a purified air supply of 160 l/min is enough, and for heavy work, the need for oxygen requires an increase in the purified air supply to 340 l/min. It is worth noting that a person needs 0.5-3 liters (rest/heavy work) of pure oxygen per minute in the volume of inhaled air for breathing. The use of two gas mask filters does not allow reaching the maximum required air supply mode with an oxygen content in the volume required by the body.

In the known solution, the air purified in filters entering the body cavity is directed directly through a hose into the under-mask space, which is currently recognized as dangerous in the case of repeated (non-replaceable) use of gas mask filters. During storage or in the intervals between uses of the device (shift work), the toxic substances accumulated in the filter can desorb and migrate to the outlet for purified air, so that the filter itself becomes a source of danger. The risk depends on the properties of the gas and the filter, the amount of accumulated harmful substance, the duration and conditions of storage or non-use. Since the subjective reaction of the worker's senses turned out to be an unreliable criterion for assessing the service life of the filter, it was prohibited to use it for this purpose (both in single and repeated use of filters) (publications in the Journal of the ISRP; National Institute for Occupational Safety and Health (NIOSH); US Occupational Health and Safety Administration (OSHA), Taylor & Francis, Springer, Oxford University Press). Scientific studies have shown that gas desorption during storage of filters, showing that desorption to a dangerous degree is possible when protecting not only from organic compounds with a low boiling point (Tk) (up to 65°C), but also at a higher Tk, as well as when protecting from some inorganic substances.

Thus, it is necessary to solve several problems: ensuring standardized air pumping through gas mask filters in the area where there is no resistance to air flow and with an increase in the pumping volume, eliminating the ingress of residual products and mechanical impurities that have entered the housing after passing through the filters, improving the design of the impeller rotation drive and the conditions of its rotation to eliminate the transfer of load from the impeller to the drive electric motor and ensuring increased air pressure.

This utility model is aimed at achieving a technical result consisting in increasing the safety of using a multi-filter device for cleaning contaminated air by eliminating the design of limiting high volumes of cleaned air supply to the sub-mask space.

Said technical result is achieved in that in a device for forced supply of purified air to a respiratory protective device comprising a housing, in the cavity of which an impeller is placed, driven into rotation by an electric motor, and an autonomous power supply unit connected to the electric motor and the button for switching on the latter, wherein on the outer side of the housing two gas filters are fixed opposite each other, each communicating with the cavity of the housing, as well as a branch pipe for connecting a hose, the other end of which is communicated with the internal volume of the respiratory protective device, on the side of the housing located between the two fixed gas filters a third gas filter is placed, communicated with the cavity of the housing, the cross-flow impeller is pivotally placed on an axis in bearings in a casing placed in the housing and made with a branch pipe brought out of the housing through an opening, and with a central opening on one side of the casing, communicated with the cavity of the housing, and the DC electric motor is made as a brushless inverter with control from a controller with feedback, connected with a button for adjusting the power of the electric motor, and is placed independently on the other side of the casing wall, and the impeller is made with elements sensitive to the electromagnetic field created by the electric motor when the rotor rotates, while the controller of the DC electric motor is made with the function of multiple increase in the rotation speed with each press of the button.

The body is equipped with elements for securing the device to the user's body; in particular, the elements can be made in the form of brackets for securing the device to a belt.

The specified features are essential and are interconnected with the formation of a stable set of essential features sufficient to obtain the required technical result.

This utility model is illustrated by a specific example of implementation, which, however, is not the only possible one, but clearly demonstrates the possibility of achieving the required technical result.

Fig. 1 - general view of the device from the front side;

Fig. 2 - the same as in Fig. 1, view from the back side;

Fig. 3 - casing for placing the impeller inside the housing;

Fig. 4 - cross-flow impeller.

According to this utility model, the design of a device for forced supply of purified air to a respiratory protective device (protective devices include masks, half masks, hoods worn on the head and everything that allows isolating the respiratory organs from the external environment) is considered. Like the prototype, the device ensures the supply of purified air to the under-mask space in a forced mode, i.e. under excess pressure, which is higher than atmospheric. This allows the use of loose-fitting masks or hoods. The high-pressure zone under the mask does not allow air from the environment with a pressure lower than the pressure under the mask to enter. Another feature is that the user does not force the purified air through gas mask filters due to his own breathing/suction, which makes the user's breathing comfortable without overloading the lungs.

The body 1 is made thin-walled from a polymer material (for example, from ABS plastic) in the form of a box having a front 2 and back 3 walls and side walls between them. The box is hollow and has on three side walls (except for the upper 4) openings with elements of threaded attachment of gas filters 5 of generally accepted designs. In this case, all filters can be of the same class and have a specific focus for disinfecting contaminants of one type, for example, a filter with the capture of aerosol consistencies or organic gases and vapors or inorganic gases and vapors or ammonia and its derivatives, etc. But the housing design allows using a combination of filters with different natures of air purification contaminated with various components, for example, one filter is anti-aerosol, and other filters are gas filters to protect against special SX compounds or against several different harmful gases of the A2B1 brand (cyclohexane C ₆ H ₁₂ , chlorine C ₁₂ , hydrogen sulfide SH ₂ , hydrogen cyanide HCN). Such a combination significantly expands the protective capabilities of the device, especially in conditions when the type of contamination is initially unclear. All types of gas masks FPK with threads according to GOST 12.4.214-99, 40x3.5 are suitable as filter elements.

The production of the housing from a polymer material allows to significantly reduce its weight and the weight of the device as a whole. Thus, pilot batches have shown that the entire device with a polymer housing and three filters weighs less than 1 kg. A symbiosis of polymer and metal is possible, for example, the back wall can be made in the form of a removable metal plate, but this leads to the fact that the weight of the device approaches 2 kg. Production of the entire housing from metal is impractical due to a noticeable increase in weight.

On the upper side wall 4 of the housing 1, on which there are no elements for connecting filters 5, there is a control button 6 and a through hole for the output of the pipe 7 of the casing 8, in which the impeller 9 is located (Figs. 3 and 4). The area of the hole around the pipe at the place of its output is sealed with a seal or other means, which makes it possible to exclude the suction of gases from the external environment during the operation of the impeller.

A hose (not shown) is connected to the branch pipe 7, the other end communicates with the internal volume of the respiratory protection device (not shown).

On the back wall 3 of the housing, elements for fixing the device on the user's body are fixed. For example, these elements can be made in the form of brackets 10, through which a waist belt is passed. This allows the user to wear the device on the waist on the lumbar side. The hose passes along the back or over the shoulder and is inserted under the mask or under the protective hood.

A casing 8 with an internal cavity corresponding to the dimensions of the impeller 9 located on the axis 11 in this casing and taking into account that the impeller must rotate freely is fixed inside the housing. The impeller is made according to the design of the impeller of transverse pressure, i.e. the air flow directed to the impeller blades from the blades is diverted in a direction transverse to the axis of rotation of the impeller. This transverse direction is the outlet through the branch pipe 7 of the casing. When installing the casing assembled with the impeller, the branch pipe is led out through the opening in the housing. The casing and impeller are made of a polymer material in order to reduce weight. This design reduces the inertial moment of the impeller, which allows it to be quickly transferred from one speed mode of rotation to another without a transitional delay for mass swinging. The axis of rotation of the impeller is removable and is installed in rotation supports in the casing. With the correct selection of the polymer material of the impeller and the axle, it is possible to ensure the sliding of the impeller on the axle with virtually minimal friction. To reduce the effect of friction, it is possible to have the impeller sit freely on the axle, and the axle is freely secured in bearing supports.

The casing is made with a central opening 12 on the front side of the casing, communicating with the cavity of the housing. This opening is smaller than the impeller diameter and is used to suck in air mass from the cavity of the housing into the blade rotation zone. With this design, mechanical particles and other inclusions that can pass through the filters, as well as particles of filter material from the filters themselves, getting into the zone between the casing and the walls of the housing, settle on the bottom of the housing and do not get into the operating zone of the impeller.

On the back side of the impeller, on its surface or in its body along the circumference, elements (not shown) are located at a distance, sensitive to the electromagnetic field created by the DC electric motor during rotor rotation. On the back side of the casing or on the fastening elements in the housing, an electric motor (not shown) is placed that drives the impeller into rotation. This electric motor has no mechanical connection with the impeller and is placed opposite the impeller autonomously. On the side of the electric motor, under the back wall, an autonomous power supply unit (a set of accumulators or batteries) is also placed, connected to the electric motor and a button. On the front wall of the housing, a 4-segment battery charge indicator is placed (0-25%, 25-50%, 50-75%, 75-100%).

The DC electric motor is a brushless inverter motor controlled by a feedback controller, which is connected to button 6. The controller is a programmable microprocessor.

This button is the switch on/off button for the electric motor and its speed regulator (electric motor power adjustment). The first time the button is pressed, the autonomous power supply unit is connected to the electric motor, and power is supplied to the controller. The electric motor starts rotating at a speed that ensures the supply of purified air to the hose in the amount of 160 l/min. The second press of the button increases the rotation speed of the electric motor to a volume of 220 l/min. The third press of the button allows you to reach the maximum supply mode of purified air - 340 l/min. The fourth press of the button disconnects the electric motor from the autonomous power supply unit and the entire device stops working. An option is possible, according to which two buttons can be placed on the body: one for switching on/off, and the second for adjusting the electric motor power.

Taking into account such an operating algorithm, the use of three gas mask filters will allow to solve the problem with the filtration system capacity. It is known that the capacity coefficient of a gas mask filter on the graph is expressed as a descending arcuate curve, showing that with an increase in pressure at the filter inlet or a decrease in pressure at the outlet, the volume of purified air decreases. For example, when pumping 30 ^dm3 /min, the resistance at the filter inlet is 100 Pa, and when pumping a volume of 95 ^dm3 /min - 400 Pa or more, depending on the filter brand (GOST R 12.4.251-2009 "Occupational safety standards system. Personal respiratory protective equipment "GAS AND COMBINED FILTERS" General technical requirements. Test methods. Marking"). The filter begins to work with a slowdown in capacity. This is explained by the fact that the air passes through the filter material, or more precisely, through the voids and microgaps between the particles of the filter material. Cleaning occurs due to contact of inclusions in the gas with fibers or powder of the filter material. But when the pressure increases, the particles of the filter material are compacted, reducing these voids and microgaps. Therefore, each gas mask filter works well at low pressures. Only in this case, contaminated air can be cleaned up to 98-99%.

In the declared device, all filters operate in a standard mode, regardless of the volume of pumped air, since the total pressure and total throughput are the sum of the operation of all three filters. In this mode, all filters operate at the initial section of the throughput coefficient drop curve. This is also explained by the fact that all filters are provided with one impeller, which sucks in the total air flow from all filters.

The use of a brushless inverter DC motor eliminates the problem of brush-collector unit wear. Brushless DC motors are a type of synchronous motor with permanent magnets that are powered by a DC circuit through an inverter controlled by a feedback controller. The controller supplies the motor phases with the voltages and currents necessary to create the required torque and operate at the required speed. Such a controller replaces the brush-collector unit.

The stator carries the windings supplied with current, and the rotor carries a permanent magnet, which may have one or more pairs of poles. When voltage is applied to the stator winding, the winding creates a rotating magnetic field. This interacts with the permanent magnet on the rotor and sets it in motion. As the rotor turns, the vector of its magnetic field rotates towards the magnetic field of the stator. The controller monitors the direction of the rotor magnetic field and changes the voltage applied to the stator winding so that the magnetic field created by the stator windings rotates ahead of the magnetic field of the rotor. The resulting magnetic field captures sensitive elements on the impeller and causes the impeller to be attracted to the magnet (SU 1272031, SU 1097845, RU 107308). Since the collector alternately supplies voltage to the stator windings arranged in series, it turns out that the magnetic field passes along a circle. The impeller also passes this path. The absence of a mechanical connection between the electric motor and the impeller allows this electric motor to operate without a load on the rotor shaft, which increases the durability of the drive unit of the device.

The declared device can be used in work with especially dangerous infections and in pathogenic environments, in the chemical industry, the pharmaceutical industry, in the liquidation of the consequences of accidents and disasters, for protection against hazardous chemicals, biological warfare agents and radioactive substances, for cleaning and supplying air to biological isolators, during welding, grinding, mechanical treatment of surfaces, in dusty environments, in the automotive and shipbuilding industries, in construction, in the food industry, in the oil industry and agriculture.

The excess pressure created by the air blower allows avoiding the need for tight fit of the face parts along the seal line, fogging of the viewing screens of the face parts, and the ingress of harmful substances into the sub-mask space.

Claims (2)

1. A device for forced supply of purified air to a respiratory protective device, comprising a housing, in the cavity of which an impeller is placed, driven into rotation by a DC electric motor, and an autonomous power supply unit connected to the electric motor and a button for turning on the latter, while three gas mask filters are fixed on the outer side of the housing, each of which is in communication with the cavity of the housing, as well as a branch pipe for connecting a hose, the other end of which is in communication with the internal volume of the respiratory protective device, characterized in that the impeller is mounted pivotally on an axis in bearings and is placed in a casing placed in the housing and made with a branch pipe brought out of the housing through an opening, and with a central opening on one side of the casing, communicated with the cavity of the housing, and the DC electric motor is made of a brushless inverter with control from a controller with feedback, connected to the button for adjusting the power of the electric motor, and is placed autonomously on the other side of the wall of the casing, and the impeller is made with elements capable of gripping magnetic field created by the electric motor when the rotor rotates, while the controller of the DC electric motor is designed with the function of multiple increase of the rotation speed with each press of the button. 2. The device according to item 1, characterized in that elements for securing the device to the user’s body are attached to the body.