ES2876051B2 - PROTECTION PROCEDURE TO REDUCE INTERPERSONAL CONTAGION MEDIATED BY RESPIRATORY PARTICLES OR AEROSOLS - Google Patents

Description

DESCRIPTION

PROTECTION PROCEDURE TO REDUCE CONTAGION

INTERPERSONAL MEDIATED BY RESPIRATORY PARTICLES OR AEROSOLS

TECHNIQUE SECTOR

The invention falls within the field of Engineering and safety and hygiene in public spaces and workplaces, as well as health prevention and personal protection.

BACKGROUND OF THE INVENTION

The COVID-19 pandemic has highlighted the great ease of spreading diseases through droplets or aerosols produced by coughing, sneezing, or simple breathing. The droplets, microscopic in size, remain suspended in the air for a considerable time and move rapidly, reaching distances of several meters from the emitting person before falling by simple gravity.

These particles can carry large amounts of viruses or infectious agents, and can infect people near or passing through the invisible cloud that forms up to several meters away from the emitting person.

The prevention of this form of contagion is very complicated. It can only be partially reduced by socially aggressive procedures, interpersonal distancing, and the use of masks. The aforementioned pandemic has shown worldwide the susceptibility of all human societies to contagion due to simple proximity, which has forced the adoption of extreme confinement and distancing measures at great economic and social cost.

Interpersonal distancing only seeks to reduce the probability that a person will become infected by inhaling respiratory particles emitted by another person nearby, leaving a space, and with it a time, for the droplets and aerosols to descend by gravity and move away from the height of entry into the airways by inhalation.

In closed or semi-closed areas and with people staying for long periods of time, the probability of contagion through this route is very high due to the accumulation and permanence of these particles in the air, even if a certain physical distance is maintained. This situation occurs, for example, in public transport such as buses, trains, boats or planes, in teaching classrooms, waiting rooms in health centers, shops, shopping centers, or catering establishments such as bars or restaurants.

In these places, distancing entails an even economic cost, as the capacity or the number of passengers per vehicle is reduced. But in addition, distancing is not very effective as a preventive measure, since suspended particles accumulate over time in the room, even within a range of minutes, and are inevitably inhaled by everyone present. In a classroom, during a typical one-hour class, everyone present shares the same air several times, along with all the suspended particles it contains.

Commonly used masks only prevent the emission and eventual reception of relatively large particles, such as small droplets of saliva. They do not prevent the emission or inhalation of aerosols as they are not hermetic. In closed spaces and in prolonged stays, such as a teaching class, they do not avoid sharing the air and all the microparticles in suspension.

Another case is people located in fixed posts exposed to the proximity of many surrounding people or passing through, such as shopping center checkouts, concierges, information or management points, or medical consultations.

In some of these cases enclosures or separation screens can be created, but the isolation can make it difficult to get the job done. The separation screens do not prevent the passage of the clouds of respiratory particles from the people who pass through the post and the simple passage produces turbulent currents that facilitate the elevation of these clouds and their passage to the other side of the screen. These fixed devices also require regular cleaning and disinfection.

In semi-enclosed public spaces, ventilation can even be counterproductive, as it can generate horizontal airflows that help spread clouds of respiratory particles and cause them to travel much greater distances from the emitting person, or come into contact with and be inhaled by many more people in the room.

Most air renewal systems with filtration can actually be counterproductive, since they generate horizontal and/or turbulent currents that objectively worsen the situation by increasing the speed of distribution, reach, and maintenance at the inspirable height of the aerosols released by anyone. of the people present, before they can be absorbed and filtered by the corresponding apparatus.

The purpose of the invention described here is to reduce the possibility of contagion in this type of situation by means of a simple procedure, of proven efficacy in other contexts and applications, and of relatively low cost of implementation.

The background, contexts and objectives in which the operating principle has been applied are well known and proven, and demonstrate the effectiveness of the operating principle.

One of the cases and applications is in the so-called vertical laminar air flow hoods for biological manipulation under sterile conditions.

These hoods are in widespread use in biological research laboratories. They allow easy handling of materials and media inside, maintaining sterile conditions without the need for a physical enclosure. The air flow creates a descending curtain that traps and drags all the external dust particles or those produced by the operator's breath towards lower openings, preventing them from entering the interior space and thus maintaining sterile conditions without the need for other insulation. .

Another case and application, with another purpose and generally on a larger scale, are dust-free rooms, normally dedicated to working in extremely clean conditions with very sensitive materials and electronic components. In this case, descending air flows are also used, among other elements, which usually delimit specific spaces within the room, such as work tables.

Neither has any example or application been found where the downward flow is apply to reduce the horizontal movement of respiratory particles and protect people inside spaces equipped with facilities or equipment that generate and maintain flows of these characteristics from contagion through this route.

EXPLANATION OF THE INVENTION

The invention consists of the application of descending airflow generating systems, which can be maintained in a laminar regime, to reduce the probability of interpersonal transmission of infectious diseases mediated by droplets or aerosols of respiratory origin.

Devices or installations at different physical scales that implement this operating principle are described and claimed, such as those expressed below, ordered from smallest to largest scale of physical dimensions:

a) Portable personal protection equipment that generates descending air flow curtains that protect the operator's face and airway entrance. b) Devices or fixed installations generating open descending air flow curtains, as a screen, or complete perimeter cabins for the protection of workers in localized positions, such as supermarket cashiers, offices, concierges, or medical consultations.

c) Devices or installations that generate a downward flow of air throughout a closed or semi-closed cabin, intended by its function for the simultaneous or successive presence of a number of people, such as public transport vehicles, buses, trains, ships or planes. , or architectural public spaces, such as classrooms, movie theaters, bars, restaurants, offices or commercial premises, elevators, toilets, changing rooms, waiting rooms or corridors, for example in hospitals, airports, stations or shopping centers.

The principle of operation in all cases is based on the fact that a constant downward flow of air, which can be maintained in a laminar or quasi-laminar regime, greatly accelerates the rate of descent of the suspended particles, specifically for the purpose of this patent. , from the droplets and aerosols of respiratory origin emitted by a person with simple normal breathing, or those produced by coughing or sneezing that are projected at high horizontal speed.

The descent entrained by the downward airflow quickly moves the particles away from the entrance height of the respiratory tract and to a much shorter distance from the emitting person. Thus protecting the rest of the people close to or sharing the space from the possibility of contagion.

With this, it is possible to effectively imitate the effect of interpersonal distancing, achieving or improving the result of reducing the probability of contagion by this route even in situations of greater proximity, such as a bus or a plane, where it is impracticable as a permanent measure. , even at an economic level, the maintenance of a great separation between passengers.

It is also possible to greatly improve the reduction in the probability of contagion in situations of prolonged stay with more people in limited spaces, such as a teaching classroom or a waiting room, or even on long journeys in the previous example of a bus, train or plane, since it allows a renewal of the entire volume of air in the enclosure, but avoiding lateral or turbulent flows.

The descending air flow, which can be in a laminar or quasi-laminar regime, which is to be generated and maintained with these devices or installations does not need to be very strong. In fact, the laminar regime is only achieved in smooth flow situations. It can even be perceived less than the air emitted by an air conditioning unit, therefore it would not be noisy or intrusive either.

This type of downward air flow, which can be in a laminar or quasi-laminar regime, is easily disturbed locally, for example by the movement of people, but with the advantage that it recovers very quickly. Whatever the cause of the disturbance, the effect is that a turbulent movement of the air is generated in an area. The turbulence is the same as that which would occur in the absence of laminar flow, in a space with theoretically still air, but the duration of the turbulent movement is much less when a downward flow is maintained in this space, which may be in a laminar regime. There are experiences that demonstrate the rapid recovery of the flow and the possible laminar regime after the disturbance.

Therefore, the main result of the invention can be understood as a mechanism for amplifying the effect of interpersonal distance and reducing the effect of time. of permanence in collective spaces.

The downdraft installation itself may include HVAC elements such as cooling, heating, or humidity control. This is also very convenient given that turbulent flow sources, such as air conditioning units, or convective ones, such as various heating systems, are very counterproductive in practice since they distribute respiratory aerosols more rapidly and farther and even contribute to their elevation to the height of the airway inlets of all persons present.

As an additional benefit, the laminar air flow system facilitates the reduction of dust, allergens or particles of environmental contamination in suspension, providing much cleaner and healthier air in premises for collective, simultaneous or successive use.

BRIEF DESCRIPTION OF THE DRAWINGS

As a complement to the description that is being made in the text and in order to help a better understanding of the characteristics of the invention, a set of drawings is attached as an integral part of said description, where, with an illustrative and non-limiting nature, , the following is displayed:

Figure 1.- Shows a section diagram of the operation of an installation generating a downward air flow in a generic room. The lines with arrows represent the airflow.

Figure 2.- Shows a diagram of an installation that generates a descending air flow forming a protection curtain for localized workers exposed to contact with many people, exemplified by a store cashier.

Figure 3.- Shows a sketch of an installation that generates a descending air flow forming protection curtains for a catering table.

Figure 4.- Illustrative example of an installation in a room. The case of a bus is shown, but the concept is equally transferable to the passenger cabin of an airplane, a train car, a ship or an elevator. It also applies to any type of architectural enclosure, such as a waiting room, a teaching classroom, laboratories, corridors, shops, services, changing rooms or places of passage.

Figure 5.- Schematic sketch of an autonomous and portable individual protection system based on the maintenance of a descending airflow curtain, which can be in a laminar or quasi-laminar regime, in this case protecting the face and airway entrances from a worker at risk of exposure, for example a doctor or health worker.

Figure 6.- Operating scheme of the autonomous and portable system of individual protection.

PREFERRED EMBODIMENT OF THE INVENTION

The practical realization of the invention depends on the scale of application.

For architectural enclosures, it would consist of facilities designed according to the habitual use of the space, such as a classroom, a waiting room, restaurant, shop, corridors, etc. In these cases, the upper pipes would be arranged on the ceiling, distributing the outlets according to the intended use of the room and possible furniture. These ducts can be hidden behind a double roof and only the air vents can be seen. The pipes and lower openings, for a work already built, can be distributed as elements at the height of a skirting board, under rows of seats, tables or desks, or other provisions as required or permitted by space and its use. In these architectural applications, it is more appropriate to use a configuration with open air inlet and outlet, such as the one schematized in figure 1, on the right (2), with open air inlet (2a) and outlet (2b). To the exterior.

For spaces such as collective, simultaneous or successive transport vehicles, such as buses, trains, planes, boats or elevators, the practical implementation would consist of a design, specific for each case and model, of upper conductions, which would be integrated into the ceiling, and lower, which would adapt and integrate into the floor, side walls, pipes or even seat backs. The drive and filtration components would be housed in suitable spaces, on the roof, cargo compartments, etc. Figure 4 shows the case of a bus. In this figure, the upper exit openings are represented, indicating that they can be concentrated in areas of interpersonal separation, for example, a supposed absence or lower density is shown on the seats, but with flow curtains for greater protection between them. The lower exit openings (not shown) can take any of the following provisions exemplified in figure 1. It is important to note that the entire set would not occupy more, nor would it have greater energy or maintenance consumption, than air conditioning equipment in these same vehicles. In the case of airplanes, since they keep the cabin pressurized, it is essential to use a closed circuit or air recirculation configuration such as the one schematized in figure 1, on the left (1), where a connection is represented between the top and bottom elements.

The main elements of these installations are schematized in figure 1. (A) upper airflow outlet element, containing the outlet openings, on the surface or in ducts (A1) with multidirectional outlets, and internal outlet regulating structures of air, which can be maintained in a laminar regime. (B) lower element with openings for the entry of airflow. (C) air delivery devices that allow maintaining an air outlet flow from the upper element (A) and air collection or absorption in the lower element (B). (D) air filtration devices. (E) biological inactivation devices, for example by ultraviolet radiation, condensation and possible freezing by cold trap or other methods of inactivation of biological agents. (F) to (K) diagram of different possibilities of arrangement of the openings in the lower element: (F) floor with openings distributed over the entire surface; (G) openings limited to specific areas of the floor; (H) openings in elevated elements, such as railings, seat backs, etc.; openings in vertical walls, (J) close to the ground or (K) higher. (L) air conditioning devices integrated into the air flow system, which avoid the need for other procedures that generate turbulent air flows (fans, air conditioning) or convective (various heating systems). This air conditioning, heating or cooling device can also incorporate systems for regulating relative humidity in the air flow, humidification or dehumidification.

Another embodiment of the invention consists in the creation of forms of protection for localized work spaces, such as cash registers, offices or medical consultations, for example. Figure 2 shows a diagram of this type of facility. The lines with arrows represent the airflow. The outlet (A) and inlet (B1) (B2) openings of the air flow are represented. For simplification of the figure, the ducts, driving elements or filters that would be equivalent to those schematized in figure 1 are not shown. (1) On the left is an installation with inlet openings (B1) on the ground , approximately vertical to the upper outlet openings (A). (2) An alternative arrangement is shown on the right, with entrance openings (B2) on the sides of the cashier's furniture. The air conduction and distribution of outlets and inlets can form a closed perimeter around the work station (not represented in the figure). This same provision can be applied to any work in localized positions exposed to the passage of other people, such as in a medical consultation. These installations can incorporate screens (C) that cover part of the surface, helping to stabilize the flow curtains and increasing the protection of workers and the public.

The practical embodiment to provide special protection to the localized worker can take the form of furniture elements that incorporate the pipes, driving elements and filters. These can generate flow curtains for protection in certain directions, or complete perimeter curtains. The lower openings can be on the floor, but they can also be located on the vertical walls of the furniture element, always below the expected height for the entrance to the respiratory tract. The same constructive idea can be applied, for example, to a bar counter or a hotel reception, for example. These applications can provide additional protection for exposed workers also within other larger spaces that can maintain a downward flow throughout the facility for the general protection of the public.

For certain spaces for social use, such as bars, restaurants or even communal dining rooms, the practical implementation can take the form of adapted tables that form air flow curtains that stand between diners, such as the sketch shown in figure 3. , and perimeter curtains that separate some tables from others (not shown in this figure). Clearly, these invisible barriers are much less socially disruptive than using glass or plastic partitions, require no cleaning or disinfection, and in practice may even be less expensive to install and maintain.

Finally, personal protective devices are a category of their own. It is a scale reduction of the previous designs to form a system of air ducts that manage to maintain a downward flow, which can be maintained in a laminar or quasi-laminar regime, around the head, protecting the face and airway entrances. of a worker at risk of exposure, for example a doctor or sanitarian. The other elements of the device, such as air impeller or impellers, batteries and filters, can be located in a rear structure or located in another position. These elements can also be moved to a backpack or separate accessory part, lightening the elements located on the head. The assembly can be very light, since most of the structure is made up of essentially hollow air ducts and special mechanical resistance is not sought or needed. The downflow device may be accompanied by a transparent face shield. In this case the downward flow eliminates the potential problem of internal condensation and increases the safety and effectiveness of the visor by preventing bottom or side entry due to turbulence or the wearer's breath. The schematic design is shown in figures 5 and 6.

A three-dimensional schematic sketch is shown in figure 5. For simplification purposes, the closure on the head and the fastening structure are not shown, which would be similar to that of any work helmet. The upper (A) and lower (B) rings are essentially hollow and very light air ducts, with the corresponding air inlet and outlet openings not shown. The lower ring can also contain an output circuit to the outside, forming an additional protective curtain, or a lower input (case not shown), depending on the desired applications and operation. The rear structure (C) can contain the air drive system, batteries and an outside air inlet fitted with suitable filters. In another configuration, not represented in this figure, all or part of the elements of this rear structure (C) can be moved to a backpack or additional separate part. In the extreme case, this backpack or separate part could contain all the elements, filter, impeller and batteries, and only be connected to the head structure by means of air ducts. The downflow device may be accompanied by a transparent face shield not shown in this figure.

Figure 6 shows an operating diagram of the autonomous and portable individual protection system. (A) upper air conduction and outlet element. (D) lower air inlet and conduction element. (B1) possible component of the lower element with separate air conduction and outlets forming a protective curtain under the user's face. In the rear structure, or in a backpack or additional separate part: (C) air supply devices. (D) air filtration devices, both inlet and outlet. (E) batteries for air supply devices. (1) on the left is a diagram with a possible transparent face shield (F). (2) to the right A scheme with multidirectional outlet flow from the upper element is represented, achieving a greater volume of protection (H) around the operator's face. (G) enclosure or upper shell. The centering and support harness on the head is not shown, which would be similar to that of any work helmet. This figure 6 only represents a conceptual scheme of operation.

Claims (10)

1. Protection procedure to reduce interpersonal contagion by respiratory particles or aerosols in a space for collective use, hereinafter referred to as an "enclosure", based on the maintenance of a descending air flow that includes the following stages: a) An air outlet from an upper element, b) an evacuation or collection of air by a lower element, and c) the establishment of a stable flow of downward air between both elements, with the following characteristics: I. The principle of operation is based on the fact that a constant downward flow of air, which can be maintained in a laminar or quasi-laminar regime, greatly accelerates the rate of descent of suspended particles, specifically droplets and aerosols of respiratory origin. emitted by a person with simple normal breathing, or those produced by coughing or sneezing that are projected at high horizontal speed. II. The descent dragged by the descending airflow moves the particles quickly away from the entrance height of the respiratory tract and to a much shorter distance from the emitting person, thus protecting the rest of the people who are close or who share it from the possibility of contagion the space. 2. Protection devices, characterized in that they incorporate the procedure described in claim 1, where the upper element is connected to an outside air inlet, which can be passed through filter elements and/or sterilization or biological inactivation by radiation, heat or cold trap, before the output of said upper element, and where the lower element is connected to an air outlet to the outside, which can be passed through a device for cleaning or neutralizing possible unwanted components prior to release. 3. Protection devices, characterized in that they incorporate the procedure described in claim 1, where the air outlet and inlet elements are connected to form a circuit with an internal air supply system, a filtration system to retain absorbed particles along with the air. aspirated by the lower element, and/or systems for sterilization, biological inactivation or removal of particles by radiation, heat or cold trap. 4. Protection device, characterized in that it incorporates the procedure described in claim 1, consisting of an autonomous individual protection helmet for exposed workers equipped with filters and air drive systems, which generates an air flow curtain that protects the face. and airways of the wearer and which may incorporate an accessory transparent face shield. 5. Protection device, characterized in that it incorporates the method described in claim 1, consisting of an autonomous protection helmet as described in claim 4, which incorporates a backpack or separate accessory part where one or more of the following is housed elements, filters, air drive systems and power batteries. 6. Protection device, characterized in that it incorporates the procedure described in claim 1 and according to claims 2 or 3, which is used in the form of perimeter screens or cabins formed by descending air flow curtains for the protection of people located in posts. fixed exposed to the proximity of surrounding or passing people, between the diners of a table, or separating a table from the closest ones. As an accessory, protection screens or partial enclosure can be incorporated to increase the efficiency or stability of the flow curtains. 7. Protection device for public transport vehicles, such as buses, train cars, subways, ships, planes or elevators, characterized by using the method described in claim 1 and according to claims 2 or 3, which provides space coverage usable by passengers of the vehicle, with an upper element with air outlet points distributed throughout the roof, or in elements located above the passengers, and a lower element with air absorption points distributed throughout the floor, or in elements and pipes located below the heads of the passengers. 8. Protection device for public transport vehicles, according to claim 7, characterized by using the procedure described in claim 1 and according to claims 2 or 3, with upper and lower elements with outlets and air inlets arranged to form a grid or a certain design according to the horizontal plane, so that the downward flow forms separations, cells or perimeters of greater protection, such as between seats, rows or separating aisles, and that increases the protection of people located in fixed positions such as seated passengers, vehicle driver or other people. 9. Devices as described in claims 7 and 8, characterized by using the procedure described in claim 1 and according to claims 2 or 3, for use in areas for collective, simultaneous or successive use, such as classrooms, meeting rooms, etc. cinema or theater, shops, bars, restaurants, offices, shopping centers, hospitals or others, as well as in corridors, stairs, services, changing rooms, elevators or transit areas in said premises. 10. Devices as described in claims 7 to 9 that incorporate air conditioning, heating or cooling, humidification or dehumidification systems, in such a way that the descending air flow system itself is used for these functions and the use of sources of electricity is avoided. turbulent and/or horizontal air, such as air conditioning units, fans or heaters, or generators of convective currents that may contribute to raising particles or aerosols of respiratory origin suspended from the air.