Patent Application
20130118506
Claimed invention relates to the hygiene and preventive healthcare. More specifically it relates to the methods and means for respiratory organs and eyes protection from aerosols.
There are known many methods and devices for protection of respiratory organs and eyes from aerosols. For example, in the Russian Federation patent No. 2030191 and U.S. Pat. No. 4,055,173 there are described various types of gas mask comprising a mask, tightly put on the face, air pipes and air pump supplying pure air under the mask for a breathing. However, the presence of airtight mask creates hygienic problems and discomfort for the user, namely, skin irritation and increased sweating where the user's face is in contact with the mask. Also there are restrictions for the user on the visual observation of the environment and on the voice communications. It becomes particularly clear during a long (several hours) wearing of such a device. Also the users, as a rule, tend to shun the wearing of similar devices with a mask for the aesthetic reasons.
There are also known other variants to protect respiratory organs and eyes from aerosols, which provide protective helmets (Russian Federation patent No. 2022579, U.S. Pat. Nos. 3,736,927 and 6,250,299), comprising a transparent visor covering the face, air filter, air fan with a portable power source and air pipes for aerosols purified air supply under the visor to the face. However, usage of said means leads to a limited user's visual observation and voice communications, as well as to the user's discomfort due to the considerable size and weight of said device. The helmet's wearing also violates the aesthetics appearance of the user, obscuring a significant part of the hairstyles and the face, which is violating mimic communications with other people. The visor's presence may also lead to the moisture condensation on its surface, which, in turn, leads to a loss of its transparency. In addition, the device does not preclude aerosol inhalation, because the design of the air pipes does not create directional air flow in the area of the nostrils and the mouth. Also the air flow velocity is low in this area due to the presence of the facial glass visor, so it allows aerosols to penetrate into the respiratory zone during inspiration.
Also there are known means for respiratory organs and eyes protection from aerosols (Russian Federation patent No. 2070823 and European patent application EP 0368916), comprising a fastening device on the user's head, a pump having a portable power unit and the filters, providing the source of the purified air, and the air pipes used to form the air curtain of aerosols purified air flow in the area of the respiratory organs (the nostrils and the mouth). However, there is a need for a preliminary purification of the air, which is forming said protective air curtain. It requires additional energy consumption and increases the cost, size and weight of the device. The increased weight and dimensions of the device also reduce user's comfort and convenience. In addition, passive air cleaning means (filters) do not ensure the complete removal of bacterial and viral aerosols during long term work. Also, all known active means of air sterilization (plasma discharge, UV irradiation, ozonation, etc.) contain high voltage components which could reduce electric safety of said devices. Moreover, all active means of biological sterilization during their operation provide harmful molecules and chemical radicals, which may be toxic for the user organism when inhaled.
The most close technical solution to the claimed invention is the Russian Federation patent No. 2255778, selected as the invention's prototype. Said prototype teaches the method and the device for respiratory organs and eyes protection against aerosols using a stream of preliminary purified (sterile) air for a breathing. Direction of the air stream axis coincides with the tangent line to the geometrical surface formed by the tip of the nose, chin and the jaws. Said air stream is provided using a pump with a portable power source, air filters and air flow pipes. However, according to the prototype, it is necessary to purify the air, which is forming said protective air stream. It requires additional energy consumption from the portable power source and increases the cost, size and weight of the device. The increased weight and size of the devices also reduce user's comfort and the usability convenience. In addition, passive air cleaning means (filters) do not ensure the complete removal of bacterial and viral aerosols during long term operation. Also all known active means for air sterilization (plasma discharge, UV irradiation, ozonation, etc.) contain high voltage components, which reduces the electrical safety of the device. Moreover, all active means of biological sterilization during their operation provide chemically active molecules (ozone, radicals, ions) which may be toxic for the user's organism when inhaled.
The goal of proposed invention is to create such a method and device for the respiratory organs and eyes protection against aerosols that would avoid immediate contact of protection means with the facial skin to achieve a high hygienic and aesthetic effect during a long-term wearing. Also the protection means must not block the sound channel for the conversation, and must have small overall dimensions, weight and power consumption for a high level of usability convenience and comfort.
This problem may be solved by creating a method for respiratory organs and eyes protection against aerosol particles of ambient air. According to the proposed method, the air flows are provided in the form of air curtain in front of the protected facial sites, namely, for individual or overall protection of nostrils, mouth and eyes, where, according to the proposed invention, said air flows are formed from the surrounding air without preliminary purification. Further said air streams (i.e. air flows) are directed in such a way that the stream lines do not cross the planes of the protected facial areas (inlet cross sections of the nostrils, mouth and eyes). At the same time, said air streams must carry aerosol particles beyond of said facial openings. The configuration of said air streams is chosen in such a way that any vector, carried out from any point of the space around the face to any protected facial opening, must be intersected by, at least, one of said air streams. Also the air stream velocity and its cross section must be chosen in such a way that aerosol particles, trapped by the stream from the surrounding space, would be accelerated enough to be ejected beyond of the protected facial areas.
Thus, if the aerosol particle tries to penetrate a breathing hole (nostrils, mouth), it will be obliged to cross the air stream which is generated in the form of the air curtain in front of said breathing hole. At the certain ratio between the mass of the particle, its cross-section size and the air stream velocity, the particle is captured (deflected and accelerated) by the air stream and is further moving at the speed of said air flow away from the protected breathing hole.
It is expedient that said air streams would be directed along the line of the lips towards from the cheeks to the nose.
Also it is expedient to direct these air streams perpendicular to the line of the mouth, from top to bottom.
Another variant of the invention is to form said air streams by air injection through the air pipes using a compressor powered by a portable source.
Also it is possible to create said air flows by a pumping of the air out of the area in front of said facial sites through the air pipes using a pump powered by a portable source.
Another variant of the invention is to attach said air pipes to the spectacle frame.
Also possible variant of the invention is to attach the air pipes to the phone headset frame.
Another expedient variant of the invention is to mount the air pipes on the dress.
One of expedient variants of the invention is to mount the air pipes on a headdress.
The technical result achieved by the proposed invention is in substantial reduction of energy consumption, size and weight of the device for implementation of the method proposed, as well as in a higher electrical safety level and in resolving of the problem with a toxic influence of air purification system on the user's organism.
The goal of the invention may be also achieved by the device for protection of respiratory organs and eyes against aerosol particles from the surrounding air. The device comprises fastening means to orient said device relative to person's face; at least one pump with a portable power supply source; air pipes connected to the pump and designed to form air streams in the form of protective air curtain before the protected sites of the face, including simultaneously or separately person's nostrils, mouth and eyes. According to the claimed invention, the pump is designed with a possibility to form the specified air streams directly from the surrounding air; outlets of the air pipes are directed relative to the face in such a manner that air flow lines don't cross the plane of entrance openings of protected facial sites. Said air streams must have such configuration that any vector, carried out from any point of the surrounding space through the air to the inlet opening of the protected facial site, is crossed, at least, by one of said air streams. Available pump rate must be taken into account: said air stream cross-section configuration and velocity must be chosen so that the acceleration, acquired by aerosol particle getting to said air stream from surrounding air, would be enough for its deflection from the protected facial opening.
One of the possible variants of the present invention comprises a vacuum pump for said air flows formation.
Another possible variants of the present invention comprises a compressor for pressurising ambient air to form said air streams.
Also possible is to use an axial fan as said compressor.
Another variant is to use a centrifugal fan as said compressor.
It is expedient that said air pipes are mounted in such a way that the air streams are directed along the line of the lips towards from the cheeks to the nose.
It is also expedient that said air pipes are mounted in such a way that the air streams are directed perpendicular to the mouth line from top to bottom.
It is expedient that said air pipes are mounted on a spectacle frame.
It is expedient that said air pipes are mounted on a phone headset frame.
It is possible to mount said air pipes on a clothes collar or on a headdress.
It is expedient to mount one or more air flow speed sensors on said air pipes for automatic regulation of the air flow rate at the protective air curtain to guarantee interception of aerosol particles when the velocity of the incident air with aerosols is increased.
The technical result achieved by the proposed invention is a common one both for the method of respiratory organs and eyes protection from aerosols and for the device for its implementation. It is substantial reduction in energy consumption level, size and weight of the device, as well as improvement in electrical safety and prevention of toxic influence by air sterilization system on the user's organism.
In addition, the proposed device does not provide difficulties for breathing, leaves open the mouth and the nose of the user and is not in a contact with the skin.
For a better understanding of the claimed invention some variants of the invention embodiment are described with the references to the following drawings:
The claimed method of respiratory organs and eyes protection from the ambient aerosol particles provides air streams in the form of the air curtain in front of the protected facial sites, including individual or overall protection of the nostrils, mouth and eyes. These air streams are formed from the surrounding air without preliminary purification, said air streams are directed in such a way that the air flow lines do not cross the plane of the protected facial openings and are caning away aerosol particles from protected facial openings. Configuration of these air streams are chosen in such a way that any vector, carried out from any point of the face surrounding space through the air to protected openings, is crossed by, at least, one of said streams. The speed and the cross-section of the air stream are chosen in such a way that acceleration provided by said air stream to aerosol particles is sufficient for a deflection of aerosols incident from the surrounding air and for ejection of these aerosols away from the protected areas.
Said air streams can be directed, for example, along the lips line from the cheeks to the nose, or perpendicular to the mouth line, from top to bottom. These air streams may be provided by pressurising of the air through the air pipes using compressor with a portable power source or by a sucking out of the air from said facial area through the air pipes using vacuum pump with a portable power source. These air pipes may be mounted, for example, on a spectacle frame, on a phone headset frame, on a clothing or on a headdress.
It is common known that healthcare problems occur when human is exposed to harmful aerosol particles, which are inhaled through the nostrils and mouth. In particular, the flu virus and the tuberculosis bacilli are transferred by airborne droplets from person to person. Aerosol particles, dangerous when inhaled, have sizes from 0.1 μm or more (in a smaller aerosol particle bacterium or virus can not be accommodated) and are suspended in the air, where they make enough long chaotic Brownian motion before falling to the ground. Aerosol particles with size of 100 microns or more quickly fall out of the air. Aerosol particles with size more than 10 μm can not penetrate into the most vulnerable sections of the lower lungs, as when they move on the heavily curved trajectories through the respiratory tract (nose, throat and trachea), they will likely settle on the upper respiratory tract walls, where their pathogenic effect is lower. It is well known that the average speed of the Brownian motion of aerosol particles in a still air under normal conditions is 0.1 m/s or less. It means that these aerosol particles almost stand still in the air, and people, coming in the area of their location, simply suck them during inspiration.
Obvious, that the most dangerous from the point of view of a possible disease transfer for a person it is staying in a room, where ill people may extend viruses and bacteria by airborne way through the sneezing, cough and conversation. Very often there is no significant air motion here (but a good ventilation could reduce concentration of the harmful aerosols). In the modern life conditions people spend most time in the closed rooms or in the public transport vehicles where the process of cross contamination during epidemics occurs. Thus, people inhale suspended particles almost motionless in the coordinates' framework connected with the room, where the particles speed relative to respiratory openings (the nostrils and the mouth) doesn't exceed 1.5 m/s (speed of a walking person). Therefore, if, according to claimed invention, to create air stream (air curtain) parallel to inlet plane of respiratory opening with sufficient flow speed (for example, 10 m/s and more), the aerosol particle, which has got to the air stream, will be caught (deflected and accelerated) by this air stream. After trapping the aerosol particle will continue motion with the speed of said air stream; this circumstance will prevent its hit into respiratory organs. Note also, that air flow speed at the nostril inlet during a breath doesn't exceed averaged 2 m/s, and it sharply falls when leaving the vicinity of the nostrils because of the rapid increase in cross-section of inhaled flow. Therefore, a breath (as the most dangerous breathing phase for aerosol penetration) doesn't change considerably the air flow vectors in said air curtain at its speed of 10 m/s and more. During breath through an open mouth the total cross-section of the inlet opening is even more compared with the nostrils, therefore the speed of inhaled air is additionally decreased, and the changes of air stream vectors at a breath through the mouth are even less. Let's also note that formation of the air curtain around the nostrils and the mouth doesn't break conditions for a normal breathing. It takes place because of air molecules have a mass, much smaller that of the aerosol particles, thus the main molecules of the air (oxygen, nitrogen and carbon dioxide), participating in breathing, move with the speed of near to 500 m/s in the free diffusion mode. It quickly equalizes any gradients of the air molecules concentration, ensuring free breathing (gas exchange) of the protected person. Thus, the specified air curtain will protect respiratory organs against penetration of incident aerosol particles through the curtain and, at the same time, provide a free breathing.
At the same time, if the aerosol particle was in the air stream at the moment of its formation (when said air stream is generated in the pump and pipes from the surrounding air with possible aerosols presence and without preliminary purification), the particle is accelerated (caught) along with the flow of the air curtain and acquires curtain's flow speed and motion vector, which is parallel to the inlet plane of the breathing hole. In this way this particle will not be able to get into said breathing hole. Such a system of nostrils, mouth and eyes protection represents a respirator with inertial gasdynamic isolation, and therefore it does not require preliminary air purification means for the air curtain formation.
In order to determine conditions for formation of protective air curtain, let's consider a spherical droplet 1 on
F=½·C·S·(v−vs)2 (1)
where:
ρ—air density;
S—the squared cross-section of the droplet;
C—dimensionless factor, which for a spherical body equals 0.47.
Mass of the droplet 1 equals 4/3·π·ρ0·R3, where ρ0 is water density, R—radius of the droplet. The squared cross-section of the spherical droplet equals to π·R2.
Acceleration experienced by the droplet 1 inside of the air stream as a function of time t is equal to:
dv(t)/dt=⅜·(ρ/ρ0)·(C/R)·(v−vs)2 (2)
Solving Equation (2) with initial conditions v(0)=0, one can find that the transverse velocity of the droplet 1 varies in time during passage of the air stream in accordance with the following expression:
v(t)=vs·t/(t+ 8/3·ρ·R/(C·ρ0·vs)) (3)
It may be derived from (3) that the time t0.5, when the droplet 1 will achieve a half of the velocity vs in the transverse direction, is equal
t
0.5= 8/3·ρ·R/(C·ρ0·vs) (4)
Taking into account that ρ/ρ0˜1000, one can get
t
0.5(sec)=0.005·R/vs (5)
where R is expressed in microns and vs—in m/s. The distance x(t), which the droplet 1 passes in the transverse direction (along the air stream vector), is determined by time integrating of the expression (3):
x(t)=vs·(t−t0.5·ln((t+t0.5)/t0.5)) (6)
Consider an example of practical implementation: let the droplet 1 of 10 μm size tries to penetrate the air curtain (air stream 2) having 2 cm thickness and 10 m/s flow speed. According to (5), in this case t0.5=0.005 s. If the droplet 1 moves through the air curtain with a speed v0=2 m/s (corresponding to a very rapid movement of the user with near to 7 km/h velocity), time of the possible crossing of the air stream 2 by the droplet 1 is equal to L/v0=0.01 s. During this time duration (equal to the doubled t0.5) in accordance to equation (3) the droplet 1 acquires speed 6.6 m/s along the air stream 2 direction and, according to equation (6), it passes distance x(t)=5 cm. The resultant velocity Vres of the droplet 1 will be about 7 m/s, and the direction of its vector is shown on
The proposed on the
According to the proposed invention, the air pipe 4 may be of various configurations, in particular, it can be used a combination of one or more pipes to protect each of the entrance openings of the breathing organs and eyes (see
It is known that, if the speed of the air stream will not exceed a few dozen m/s, the air pipes 4 with a smooth internal surface will generated a laminar air flow 2. Thus the cross section of the air stream 2 will be similar to the outlet configuration of the air pipe 4. Leaving the pipe 4, the air stream will gradually expand and slow down. Thus, to create the air curtain of the predetermined shape (width and thickness), it is necessary to provide the same shape to the outlet of the air pipe 4. For example, to protect the nostrils and the mouth, as shown on
Flow lines of the air curtain are shown on
The cases of the pumps 3, 3a, as well as of the air pipes 4, 4a, 7 may be made from a plastic to reduce weight. Additionally, one can use plastic transparent to the visible light and ultraviolet radiation, it will provide access of sunlight to the skin of the face.
Because it is necessary to provide a spatial fixation of said protective device relative to the nostrils and the mouth of the user 6, you can use a variety of options for fastening device. For example, it is possible to mount said protective device on the spectacle frame (not shown on the drawings) or with the headset frame 8, tightly fixed on the head. Also for user 6 convenience, it is possible to mount said protective device on a headdress (not shown on the drawings), a head ribbon 9 or with a dress elements (not shown on the drawings).
Additionally, in said protective device it can be installed one or more air flow speed sensors (not shown on the drawing) for automatic regulation of the air curtain flow rate and for the enhanced interception of aerosol particles in the case of the increase in the oncoming speed of the ambient air. It also permit to save battery power, when the surrounding air is practically motionless and the flow rate may be decreased. In this case, for example, one can use well known design of the open case thermo-resistors installed inside of airflow to be measured. Said thermo-resistors with the stabilized heating means as an airflow speed sensors, microprocessor for data analysis from said thermo-resistors and DC-DC converter for a voltage supply regulation of the pump motor power are possible to use for this purpose.
The pumps 3 and 3a are tightly connected with air pipes 4 and 4a with rectangular outlet cross-section to form a protective air curtain with required width and thickness. Pumps 3 and 3a are mounted by the frames 8, 8a to the headset, which provides secure fixation of the device at the user's 6 head. Air pipes 4 and 4a are attached in such a way that their axes are intersected at some angle to each other (for example, 90°) to avoid opposing interference with each other. In this case at the streams' intersection region the resultant airflow will be directed opposite to the person's face and will throw away the captured aerosol particles. Anatomical features of user's 6 face (which is convex in a horizontal section plane) contribute to the easy implementation of the necessary intersection angle. Also the pumps 3 and 3a are cable connected to a power source with a turn on/off switch (are not shown on
Said device is sucking surrounding air (as shown on the
On the
The proposed method and the device are designed to prevent harmful aerosols (bacteria, viruses, allergens in various forms, including liquid drops, as well as various kinds of dust) penetration into the human respiratory system, including the upper respiratory ways, as well as in the eyes and on the skin of the face.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009140206 | Oct 2009 | RU | national |
This application is a Continuation of PCT application serial number PCT/RU2010/000581 filed on Oct. 13, 2010, published as WO 2011/049485 A1 on Apr. 28, 2011, which claims priority of Russian application serial number 2009140206 filed on Oct. 23, 2009, and both of which are incorporated herein by reference in their entirety.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/RU2010/000581 | 10/13/2010 | WO | 00 | 1/9/2013 |
