JP7737590B2 - Droplet diffusion prevention system and droplet diffusion prevention device - Google Patents

Description

The present invention relates to a droplet diffusion prevention system and droplet diffusion prevention device that prevent droplets generated by conversation from remaining on the table and scattering or spreading to surrounding attendees when multiple people are dining or holding meetings around a table in a restaurant, conference room, etc., thereby reducing or preventing the risk of infection caused by droplets.

In recent years, infections caused by the novel coronavirus have become widespread, and various infection prevention devices have been proposed as countermeasures, including wearing masks and using circulators with indoor ventilation and sterilization functions, ultraviolet sterilization devices, and air purifiers. In particular, droplets generated during conversations during meals and other occasions in restaurants and homes where multiple people gather are considered a major cause of infection.
Incidentally, as a device with a sterilization function, for example, as disclosed in Patent Document 1, a circulator (1) is known, which has an air intake (5) at the lower end of the front face of a casing (4) and an exhaust (6) at the upper end, and is equipped with a blower fan (2) connected to a motor (3) and an ultraviolet germicidal lamp (10) inside (see Figures 1 and 3).

However, this device is placed near the wall on the floor of the room (R) and operated to suck in air stagnating on the floor, expel gas sterilized by the ultraviolet germicidal lamp (10) with a volume that reaches the ceiling above, and then suck in air through the floor again through the air intake (5), thereby circulating air throughout the room. The casing (4) itself is shaped like a large box, with a wide gas flow path within its internal space, allowing for a large amount of air to be sucked in, and the sucked gas within the casing (4) is sterilized by irradiation with the ultraviolet germicidal lamp (10). However, the flow path between the ultraviolet germicidal lamp (10) and the inner peripheral wall surface is also wide, meaning that the passing sucked gas rarely comes into contact with the ultraviolet germicidal lamp (10), and the contact efficiency with the sucked gas is low, so it is not possible to effectively utilize the heat generated by lighting to achieve a thermal sterilization effect through contact.

Furthermore, since a device designed to circulate air throughout the room would simply get in the way if it were placed on a table used for eating and drinking, it is possible to consider making the entire device smaller. However, this device has an air intake (5) only on one side, and when placed in the center of a table intended for face-to-face dining, such as a table that seats four people, droplets that come from multiple directions during conversations while eating and drinking, when it is difficult to wear a mask, cannot be sucked in from the side without the air intake (5), and therefore cannot be prevented from spreading, which raises the risk of infecting other people at the table, making it impractical.
Meanwhile, in restaurants, for example, it is recommended to place a transparent acrylic panel (partition) in the center of a table to separate people at the same table when dining face-to-face. However, this not only creates a sense of claustrophobia and oppression as it blocks the space between people at the same table, which is inconvenient, but it has also been reported that the maximum distance that droplets can travel during conversation is 1m, and that at least 1,000 tiny droplets are produced in one minute of speaking, and that these droplets continue to float in the air for more than eight minutes after they are generated, so there is also concern that the droplets will continue to remain floating on the table as floating droplets, and that they may jump over the acrylic panel and spread to the other person, causing aerosol infection; the risk of infection cannot be eliminated until the droplets are expelled from the table by indoor ventilation or circulation airflow to prevent infection.

Japanese Utility Model Application Publication No. 61-6128

The present invention was devised to eliminate the problems described above, and uses an intake and exhaust device that sucks in gas through an intake port on the bottom and exhausts it through an exhaust port on the top. However, the intake and exhaust device itself is small enough to be placed upright on a table that can accommodate multiple people, such as a two-seater or four-seater, so that it does not get in the way. By having a conversation while facing the device, droplets that come from multiple directions, especially those that are generated when talking while eating or drinking, when it is difficult to wear a mask, are immediately sucked in and sterilized or inactivated to a certain extent by a sterilization means before being discharged to the ceiling. This rising exhaust airflow functions as an air curtain, preventing any airborne droplets that escape being sucked in from spreading to the seated person opposite. The object of the present invention is to provide a droplet spread prevention system that reduces or prevents the risk of infection caused by droplets remaining on the table by fluidizing the gas above the table so that it joins the rising exhaust airflow with the indoor ventilation airflow or circulation airflow for infection prevention, thereby reducing or preventing the risk of infection caused by droplets remaining on the table.

The technical means adopted by the present invention to solve the above problems is an intake and exhaust device that has a heat-generating sterilizing means and a blower fan inside a casing, and that draws in gas from an intake port formed on the lower side of the casing and discharges it from an exhaust port on the upper side, and the casing is formed in a cylindrical shape so that the intake and exhaust device can be placed upright on a table that can accommodate multiple people, and the intake port is formed on the outer circumferential surface area of the casing so that it can draw in gas from multiple directions , and the exhaust port is formed by opening , and the sterilizing means is disposed in a gas flow path between the intake port and the exhaust port on the inner circumferential wall surface of the casing, and a narrow ventilation area is formed between the inner circumferential wall surface and the sterilizing means to form a sterilizing area , so that when the intake and exhaust device is placed upright on the table, gas above the table in the surrounding space can be drawn in from multiple directions of the casing through the intake port The rising exhaust air flow is fluidized by generating a peripheral intake air flow that flows toward the intake port and an ascending exhaust air flow that flows out from the exhaust port, and the ascending exhaust air flow draws in gas from the intake port with a suction force that can function as an air curtain, and exhausts it from the open exhaust port, giving momentum to the ascending exhaust air flow so that it can be ejected. Droplets that are generated from multiple directions during conversations at the table are immediately sucked in through the intake port , and as the sucked-in droplets pass through the sterilization area within the casing, they are sterilized and/or inactivated to a certain extent , including by heat sterilization due to contact with the sterilization means and by the atmospheric temperature within the casing due to the heat generated by the sterilization means , before being discharged. Meanwhile, any floating droplets that escape being sucked in are entrained in the ascending exhaust air flow along with the discharge of the treated sucked-in droplets , and are then merged with the ventilation flow or circulation flow provided in the room for infection prevention.

As a result of being configured as described above, the present invention is an intake and exhaust device that sucks in gas through an intake port on the lower side and exhausts it through an exhaust port on the upper side. However, the casing is formed into a cylindrical shape to make it compact so that it does not get in the way even when the intake and exhaust device itself is placed upright on a table that can accommodate multiple people, such as a two-seater or four-seater. Furthermore, by narrowing the air passage that forms the inner peripheral surface of the casing itself, sterilization means can be disposed in this air passage area, and the intake gas can be passed through an even narrower gas flow path (sterilization area). Therefore, the contact efficiency of the inflow gas can be easily increased depending on the type of sterilization means employed. The sterilization means can effectively utilize the heat generated by an ultraviolet sterilization lamp or electric heater to provide a thermal sterilization effect through contact, and can also apply the heat-generated atmospheric temperature sterilization and ultraviolet sterilization effects to gas containing viruses and the like that pass through the narrow air passage with the inner peripheral wall surface of the casing, thereby increasing the sterilization efficiency of the intake gas.
Furthermore, in the peripheral space area centered on the air intake and exhaust device on the table, the air intake port, which has a plurality of perforations formed therein , generates a peripheral intake air flow flowing in from multiple directions with a suction force that allows the upward exhaust air flow to function as an air curtain , and can be sucked directly into the casing. The upward exhaust air flow is given momentum from the open air exhaust port, and is discharged toward the ceiling , thereby forming a flow environment of gas that flows in one direction from inflow to exhaust, and management by suitable fluidization that does not require circulatory flow can be performed. By talking toward the air intake and exhaust device, it is possible to make it easy to talk, especially for people who drink or drink and for whom wearing a mask is difficult. Of the droplets that fly from multiple directions during conversations, such as during meals, droplets that are about to fall onto the table are immediately sucked in through the air intake and discharged to the ceiling after being sterilized or inactivated to a certain extent via a sterilization means.Furthermore, any floating droplets that do not escape the suction are absorbed and entrained in this rising exhaust current and can be merged with the ventilation or circulation currents provided in the room for infection prevention.As a result, this rising exhaust current, which has been sterilized or inactivated to a certain extent , can function as an air curtain, preventing droplets from flying toward the person sitting opposite, and reducing or preventing the risk of infection caused by droplets remaining on the table.

1A and 1B are a longitudinal cross-sectional view and a plan view, respectively, illustrating an intake and exhaust device according to a first embodiment of the present invention, illustrating an internal mechanism thereof. 10A and 10B are a longitudinal cross-sectional view and a plan view, respectively, illustrating an intake and exhaust device according to a second embodiment of the present invention, illustrating the internal mechanism thereof. 1A is a plan view and a cross-sectional view showing an exhaust flow forming cap for an ascending exhaust flow that is inserted into the exhaust port of an intake and exhaust device according to an embodiment of the present invention, and FIG. 1B is a plan view and a cross-sectional view showing another embodiment. 1A and 1B show how the intake and exhaust device of the present invention is used, with FIG. 1A being an explanatory plan view of the device when placed on a four-seater table, and FIG. 1B being an explanatory plan view of the device when placed on a two-seater table.

An intake and exhaust device illustrating a preferred embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1 shows an intake and exhaust device according to a first embodiment, with (A) being a longitudinal cross-sectional view illustrating the internal mechanism, and (B) being a plan view. As shown in these figures, the intake and exhaust device 1 includes a cylindrical casing 3 standing on a base 2, a blower fan 4 and a sterilizing means 5 inside the casing 3, and is configured to draw in gas through an intake port 31 formed on the lower side of the casing 3 and exhaust it through an exhaust port 32 on the upper side. The device is sized to be able to be placed upright on a table, such as a two-seater or four-seater, so that it does not get in the way when multiple people are seated together for a dinner party.
In addition, a universal joint 3a is provided on the upper side of the casing 3 to allow for appropriate rotation and angle adjustment, so that the exhaust direction of the suction gas can be adjusted relative to the main flow of indoor ventilation flow and circulation flow for infection prevention on the ceiling side.

The casing 3 can be formed to any size, for example, with a cylindrical diameter of approximately 5 to 8 cm and a height of approximately 20 to 40 cm. The lower side of the casing 3 is provided with multiple air intake ports 31 perforated at predetermined vertical intervals around the entire periphery, allowing for suction from all directions (all circumferential directions) when placed in the center of a four-person table, for example, as shown in Figure 4 (A). The opening at the end of the tube on the upper side of the casing 3 is set as an exhaust port 32, and is configured to immediately suck in droplets from multiple directions generated by conversation through the air intake ports 31 and expel them toward the ceiling. Furthermore, when the air intake 31 is placed on a two-seater table as shown in Figure 4(B), for example, it is not necessary for it to draw in air from all directions, so it is sufficient if it can draw in gas from an arc-shaped circumferential direction of, for example, about 200 degrees. In short, it is sufficient if it is formed so that gas can be drawn in from multiple directions (multiple directions) relative to the outer circumferential surface area of the casing 3 as appropriate for the usage pattern, and it goes without saying that the shape of the air intake 31 can be changed as appropriate in various ways, including a louver type or a mesh type, etc.

The blower fan 4 consists of a dual-shaft motor 41, a blade 42a attached to the outer motor shaft, and a blade 42b attached to the outer motor shaft. The blades 42a and 42b are controlled so that they can rotate independently. The configuration of the blower fan 4 is not limited to this embodiment, and other applicable configurations can be used. In other words, while the blade 42 is illustrated as having two blades, it may be modified as appropriate to have three or more blades or a shape that satisfies the optimal function required for suction. A normal single-shaft motor may also be used.

The sterilization means 5 is disposed directly above the blower fan 4 inside the cylindrical casing 3 so that gas drawn in from all directions (all circumferential directions) comes into contact with the sterilization means 5 in a substantially uniform manner. In other words, the air passage inside the casing 3 is narrow, and the sterilization means 5 can be disposed in this narrow intra-cylindrical region with the air passage spaced equally from the inner wall surface. The gas flow path between the inner circumferential surface of the casing 3 and the sterilization means 5 passes through an even narrower air passage region (sterilization region), making it easy to arrange the sterilization means 5 to increase contact efficiency with the sterilization means 5. The sterilization means 5 may be disposed alone or in two locations similar to the one directly above the blower fan 4 in the region inside the casing 3 between the double-shaft motor 41 and the impeller 42a, or may be used in combination with a different type of sterilization means (such as an electric heater 52).
The casing 3 on the upper side of the sterilization means 5 is detachably configured so that it can be separated from the lower side via a connecting ring 3b provided on the casing 3, and this detachable configuration is achieved by inserting an inverted L-shaped groove on the inner circumference of the connecting ring 3b into a protrusion 3b1 provided on the outer circumference of the casing 3 and rotating it. This allows the upper side of the casing 3 to be removed to perform maintenance work such as replacing the sterilization means 5.

The sterilization means 5 consists of two ultraviolet germicidal lamps 51, one above the other, that emit ultraviolet light with a wavelength that is harmless to human skin and eyes. By allowing droplets to pass through the narrow interior of the tube, the irradiation distance is shortened, allowing for quantitative irradiation with strong ultraviolet light (UV irradiance) at closer range. Furthermore, the temperature of the ultraviolet germicidal lamps 51 themselves generally rises to approximately 40°C, with the highest temperature reaching approximately 50-60°C near the electrodes on both ends of the tube. It is known that the novel coronavirus, in particular, is more susceptible to inactivation due to increased temperature. Furthermore, verification results have shown that a UV-C light source can inactivate 99% of the novel coronavirus attached to the surface of an object in approximately six seconds. Therefore, efficient comprehensive sterilization and inactivation can be achieved, including ultraviolet irradiation that takes into account the ambient temperature inside the casing 3, including droplets attached to the inner walls of the casing 3, and thermal contact where droplets come into direct contact with and adhere to the ultraviolet germicidal lamps 51 themselves. Additionally, the temperature inside the casing 3 is prevented from rising above a certain level by the blower fan 4, but can be controlled by a temperature controller or temperature sensor if necessary.

In other words, the sucked droplets pass through the casing 3 within one or two seconds, but are sterilized or inactivated to a certain degree (e.g., about 30-50%) before being discharged toward the ceiling with reduced germ count (gas). Furthermore, the gas discharged to the outside of the tube through the exhaust port 32 and airborne droplets accompanying the rising exhaust airflow are irradiated with ultraviolet light to enhance sterilization, and then merged with the ventilation or circulation flow provided in the room for infection prevention. If the effective sterilization irradiation time of the lamp is limited, a dual-unit system with automatic switching can be used. Furthermore, ultraviolet germicidal lamps 51 come in a wide variety of shapes and sizes, including single-tube, serpentine, and spiral, and the one with the optimal germicidal effect can be selected for this device. The ultraviolet germicidal lamp 51 can also be mounted below the blades 42a and irradiated and sterilized on the table through the intake port 31. If an ozone-free ultraviolet germicidal lamp is used, the air passage can be blocked with a filter to prevent radiation leakage to the outside.

On the other hand, the rising exhaust air flow discharged from the exhaust port 32 toward the ceiling after being sterilized or inactivated to a certain extent by the ultraviolet germicidal lamp 51 can accompany floating droplets that escape from the intake port 31 among the droplets that are generated from multiple directions during conversations such as eating and drinking, and can be merged with the indoor ventilation flow or circulation flow for infection prevention, and can function as an air curtain to prevent droplets from spreading to the people sitting opposite.
In other words, on the table, in the peripheral spatial area centered on the intake and exhaust device 1, like the air flows indicated by the arrows in Figures 1 and 2, a peripheral intake air flow collectively flows in from multiple directions (including all directions) toward the intake port 31, and an upward exhaust air flow flows out from the exhaust port 32, creating a gas (air) flow environment in which gas flows in one direction from inflow to exhaust, without the need for a circulating flow of gas.Once exhausted, the upward exhaust air flow will not circulate back into the space above the table, and floating droplets will not continue to stagnate in the spatial area above the table.Therefore, by sterilizing or inactivating the suction droplets to a certain extent, so to speak, as a supplementary infection control measure, it is possible to sufficiently avoid, reduce or prevent the risk of infection.This eliminates the need for advanced sterilization processes that are close to sterilization, simplifies the structure of the device itself, and enables it to be manufactured inexpensively.

Reference numeral 6 denotes a droplet receiving plate. The droplet receiving plate 6 is made of transparent acrylic resin and is formed into a rectangular shape. It is attached to the outer peripheral surface of the casing 3, extending in two to four directions. Specifically, the droplet receiving plate 6 is detachably attached by inserting attachment portions 61, 61 located on the top and bottom of one end of the droplet receiving plate 6 into a pair of upper and lower setting holes 62, 62 drilled in the casing 3. This allows it to catch droplets primarily in the airspace between the intake port 31 and the exhaust port 32, where the airflow is weak. These setting holes 62, 62 are located in four directions (front, back, left, right). By attaching the droplet receiving plate 6 to extend from the casing 3 in four locations, i.e., in four directions, the spatial area around the outer periphery of the casing 3 can be divided into two to four sections. The droplet receiving plate can be configured to extend in two to four directions, depending on the arrangement of the intake and exhaust device 1 on a table, such as a four-seater or two-seater.

Although the splash receiving plate 6 is attached directly to the casing 3, it may be placed on a table in close proximity to the outer periphery of the casing 3, and the size, shape, etc. may be changed as appropriate.
By providing the droplet receiving plate 6 in this manner, droplets generated during conversation from multiple directions can be caught by the droplet receiving plate 6, falling droplets can be reliably sucked in through the air intake 31 and discharged through the exhaust vent 32, and floating droplets that do not escape suction can be entrained in the ascending exhaust airflow that functions as an air curtain discharged from the exhaust vent 32 and can merge with the ventilation airflow or circulation airflow provided in the room for infection prevention. This increases the efficiency of suction into the air intake 31 and the efficiency of entrainment into the ascending exhaust airflow, promoting the fluidization of air above the table and reliably preventing droplets from scattering toward the seated person even without the sterilization means 5, further reducing or preventing the risk of infection, such as aerosol infection, caused by droplets remaining on the table.

Next, another embodiment of the intake and exhaust system 1 will be described with reference to Fig. 2. However, detailed description of the configuration common to the first embodiment will be omitted.
Figure 2(A) is a longitudinal cross-sectional view explaining the internal mechanism, and Figure 2(B) is a plan view, showing the use of an electric heater 52 as the sterilization means 5. Examples of electric heaters 52 that can be used include sheath heaters, which are made by wrapping nichrome wire, a common heating element, in a metal pipe and allowing it to be freely bent, sheet-shaped silicone rubber heaters and sheet heaters that are highly flexible and can be wrapped around curved surfaces or cylinders to perfectly fit the object to be heated, and cord-shaped silicone cord heaters. These heaters come in a wide variety of shapes and sizes, including single-tube, serpentine, and spiral shapes, and any heater with the optimal sterilization effect for this device (other types of electric heaters are also acceptable) can be used.

As shown in these figures, the intake and exhaust device 1 comprises a cylindrical casing 3 erected on a base 2, blower fans 4a and 4b inside the casing 3, and a sterilization means 5 (electric heater 52) disposed between the blower fans 4a and 4b. The device is configured to suck in air through intake ports 31, 31a formed on the lower and upper sides of the casing 3 and expel it from an exhaust port 32 on the upper side. The casing 3 is detachably configured so that the upper side of the blower fan 4a can be separated from the lower side via a connecting ring 3b provided on the upper side. The droplet receiving plate 6 can be set to extend in two to four directions, depending on whether it is required or not, depending on how the intake and exhaust device 1 is positioned on the table in relation to the people present.

Air intakes 31, 31a are perforated at predetermined intervals along the entire periphery, allowing for suction from all directions. Blower fans 4a, 4b suck in air from air intake 31, and two blower fans 4b on mounting holder 3c are provided to suck in air from air intake 31a. Each fan is independently controlled to rotate and stop. In particular, blower fan 4b actively sucks in airborne droplets that have escaped through air intake 31 from the upper air intake 31a, improving suction efficiency. It also increases the flow rate of the ascending exhaust airflow discharged from exhaust outlet 32 toward the ceiling, improving the function of the ascending exhaust airflow as an air curtain and increasing its effectiveness in preventing airborne droplets from spreading to seatmates. It also accommodates changes in ceiling height, allowing it to merge with indoor ventilation airflow, circulation airflow, etc. when the height distance (space) is large.

The blower fans 4a, 4b each consist of a motor 4a1, 4b1 and a blade 4a2, 4b2 attached to the motor shaft. The blade 4a2 is tilted slightly upward so that the suction gas is blown toward the electric heater 52 (center of the cylinder). This means that the suction droplets are actively brought into contact with the electric heater 52, increasing the amount of contact with the electric heater 52 and efficiently sterilizing or inactivating them through thermal contact. To improve contact efficiency with the electric heater 52, instead of relying on the inclination of the blade 4a2, a ring-shaped member sloping in a V-shape may be provided near the top of the blade 4a2 to guide and guide the inflowing gas toward the electric heater 52. Alternatively, the surface of the electric heater 52 itself may be textured to improve contact.

The electric heater 52 is supported at its upper and lower parts by the mounting holder 3c, and the upper part of the casing 3 can be removed for maintenance by operating the connecting ring 3b. Furthermore, to set a temperature effective for a certain degree of sterilization or inactivation through thermal contact, the temperature inside the casing 3 is air-cooled by the blower fan 4 to prevent it from rising above a certain temperature, and this is controlled by a temperature controller and temperature sensor (not shown). The temperature setting of the electric heater 52 is adjusted by the temperature controller to an arbitrary set value of approximately 60°C (±5°C), taking into account the ambient temperature inside the casing 3 and sterilization efficiency, and the temperature sensor automatically switches the switch on and off to prevent it from rising too high. Furthermore, the electric heater 52 or an ultraviolet sterilization lamp 51 may be used in combination with the ultraviolet sterilization lamp 51 or installed in the space inside the casing 3 between the motor 4a1 and the blades 4a2.

Figure 3 shows an exhaust flow forming cap 7 for forming an upward exhaust flow that is inserted into the exhaust port 32 of the intake/exhaust device 1. (A) is a plan view and a cross-sectional view, and (B) is a plan view and a cross-sectional view showing another embodiment. As shown in these figures, the exhaust flow forming cap 7 is designed to change the outlet shape of the exhaust port 32, thereby generating an upward exhaust flow shape. It is fitted and inserted into the upper end of the casing 3, forming outlets 32a and 32b by narrowing the outlet shape of the exhaust port 32 itself. The exhaust gas passes through the narrow outlets 32a and 32b, increasing the flow rate of the exhaust flow and imparting momentum to the upward exhaust flow, improving the function of the air curtain. It also slightly retains the incoming gas within the casing 3, thereby improving sterilization efficiency. In other words, it is preferable to adjust the volume of the upward exhaust flow emitted from outlets 32a and 32b immediately after emission while maintaining the shape of each outlet 32a and 32b up to approximately above the heads of attendees. That is, by adjusting the flow rate and volume of the exhaust gas in relation to the suction force control by the blower fan 4, it is possible to efficiently absorb and entrain airborne droplets in the ascending exhaust flow that acts as an air curtain, preventing them from scattering toward the person sitting opposite.

The exhaust flow forming cap 71 shown in Figure 3(A) has slit holes 712 extending in four directions (up, down, left, and right) from a central round hole 711, thereby forming an outlet 32a in a cross shape with an overall outlet shape smaller than the cylindrical inner diameter of the casing 3. Inside the exhaust flow forming cap 71, a guide section 713 is provided that uses an inclined surface to guide the exhaust gas to the round hole 711 and each slit hole 712, allowing the inflow gas to pass smoothly through the outlet 32a without accumulating unnecessarily within the casing 3. Therefore, the exhaust flow shape of the ascending exhaust flow is generated as an air curtain in a roughly cross shape by the central round hole 711 and the four slit holes 712.

The discharge flow forming cap 72 shown in Figure 3(B) has slit-like elongated holes 721 drilled in four directions (up, down, left, and right) except for the center, which extend outward and protrude further than the cylindrical diameter of the casing 3, thereby forming a cross-shaped outlet 32b. Therefore, the discharge flow of the ascending exhaust air is generated as a roughly cross-shaped air curtain by the elongated holes 721 in each of the four directions, which can absorb floating droplets outside the cylindrical diameter of the casing 3. Inside the discharge flow forming cap 72, a guide section (not shown) is provided that uses an inclined surface to guide the discharged gas to each of the elongated holes 721.

Next, based on the explanatory diagrams of the device placed on a four-seater table as shown in Figure 4(A) and on a two-seater table as shown in Figure 4(B), we will explain in detail the system that prevents the spread of droplets on a table that occurs when multiple people are talking at a dinner party, etc.
First, when the device is placed in the center in front of the seated person (droplet receiving plates 6 are placed on the left and right), or when it is placed slightly offset from the facing position as shown in Figures 4(A) and 4(B) (droplet receiving plates 6 are placed as shown), the people face the device to talk to each other. In other words, when placed in the center of a four-person table, the air intake 31 is configured to be able to draw air from all directions (all circumferential directions), and in the peripheral space above the table centered on the device, a peripheral intake air flow is generated that flows into the casing 3 from multiple directions toward the air intake 31, and this inflow gas is discharged from the exhaust 32, generating an upward exhaust air flow.

Therefore, a gas flow environment is created on the table where the gas flows in one direction due to the peripheral intake air flow and the ascending exhaust air flow that flow toward the device from multiple directions, i.e., a flow environment created by a gas fluidization system that does not require a circulating flow in the spatial area above the table.
Therefore, droplets that are generated from multiple directions during conversation, including those that are caught by the droplet receiving plate 6, and that are about to fall onto the table are immediately sucked in through the air intake 31, sterilized or inactivated to a certain extent by the sterilization means 5, and then discharged as an ascending exhaust current toward the ceiling through the exhaust vent 32.Furthermore, any floating droplets that are not sucked in are absorbed and entrained in the ascending exhaust current that functions as an air curtain, and can be processed to join the ventilation current or circulation current provided in the room for infection prevention, preventing them from scattering toward the person sitting opposite and reliably avoiding a situation in which the droplets continue to float in the air for more than 8 minutes after they are generated, thereby reducing or preventing the risk of infection such as aerosol infection caused by floating droplets remaining in the space above the table.

In this embodiment, the cylindrical casing 3 is exemplified as a single tube, but is not limited to this. The shape can be arbitrarily changed as long as it can fluidize the gas centered on this device and achieve the air curtain function in the spatial area above the table, such as a quatrefoil or elliptical shape when viewed from above so that the ascending exhaust air flow can be separated and discharged in four directions, a convex shape when viewed from the front with the lower housing portion of the blower fan 4 enlarged to increase suction power, or a shape with multiple cylindrical bodies.

In the embodiment of the present invention configured as described above, the casing 3 is provided with a sterilization means 5 and a blower fan 4, and the intake and exhaust device 1 draws in air from an intake port 31 formed on the lower side of the casing 3 and exhausts it from an exhaust port 32 on the upper side, and is used to prevent infection through droplets generated by conversation when multiple people are dining or having a meeting around a table in a restaurant, a conference room, etc. The droplet spread prevention system of the present invention forms the casing 3 into a cylindrical shape so that the intake and exhaust device 1 is large enough to be placed upright on a table, the intake port 31 is formed on the outer circumferential surface area of the casing 3 so that it can draw in gas from multiple directions , and the exhaust port 32 is formed by opening it , and the sterilization means 5 is disposed in the gas flow path between the intake port 31 and the exhaust port 32 on the inner circumferential wall surface of the casing 3, and a narrow ventilation area is formed between the inner circumferential wall surface and the sterilization means 5 to form a sterilization area, and thereby the intake and exhaust device 1 placed upright on a table can circulate droplets. The gas on the table in the surrounding space is fluidized by generating a peripheral suction flow that flows in from multiple directions (including all directions) of the casing 3 toward the air intake 31 and an upward exhaust flow that flows out from the exhaust 32. Furthermore, this upward exhaust flow draws in gas from the air intake 31 with a suction force that can function as an air curtain, and discharges it from the open exhaust 32, giving momentum to the upward exhaust flow so that it can be ejected. Droplets that are generated from multiple directions during conversations such as during a meal are immediately sucked in through the air intake 31 , and as these sucked-in droplets pass through the sterilization area within the casing 3, they are sterilized and/or inactivated to a certain extent, including by heat sterilization due to contact with the sterilization means 5 and the atmospheric temperature inside the casing due to the heat generated by the sterilization means 5, before being discharged. Meanwhile , any floating droplets that escape being sucked in are entrained in the upward exhaust flow along with the discharge of the treated suctioned droplets , and are then merged with the ventilation flow or circulation flow provided in the room for infection prevention.

With this droplet diffusion prevention system, the intake and exhaust device 1 draws in gas through the lower intake port 31 and exhausts it through the upper exhaust port 32. However, the casing 3 is cylindrical and compact, allowing the intake and exhaust device 1 itself to be placed upright on a table that can accommodate multiple people, such as a two-seater or four-seater, without getting in the way. By narrowing the air passage in the casing 3 itself, the sterilization means 5 can be placed in this ventilation area, allowing the intake gas to pass through the narrower gas flow path. Therefore, the contact efficiency of the inflow gas can be easily increased depending on the type of sterilization means 5 employed. The sterilization means 5 not only provides a thermal sterilization effect through contact by effectively utilizing the heat generated by the ultraviolet sterilization lamp 51 or electric heater 52, but also acts to sterilize gas containing viruses and other pathogens that pass through the narrow air passage with the inner wall surface of the casing 3 through atmospheric temperature sterilization and ultraviolet sterilization caused by the heat generated by the sterilization means 5, thereby increasing the sterilization efficiency of the intake gas.

Moreover, on the table, in the peripheral spatial region centered on the intake and exhaust device 1, the intake port 31, which has a plurality of perforations formed therein , generates a peripheral suction flow flowing in from the periphery with a suction force that allows the ascending exhaust airflow to function as an air curtain, and can be sucked directly into the casing 3. The exhaust port 32 generates an ascending exhaust airflow that is given momentum and ejected toward the ceiling, creating a flow environment in which gas flows in one direction from inflow to exhaust, allowing for management by suitable fluidization that does not require circulatory flow . By talking toward the intake and exhaust device 1, droplets from multiple directions that are generated when talking, especially when eating or drinking, where it is difficult to wear a mask, can be prevented from flying toward the table. Droplets attempting to fall upward are immediately sucked in through the air intake 31 and sterilized or inactivated to a certain degree by the sterilization means 5 before being discharged as an ascending exhaust airflow toward the ceiling. Furthermore, any airborne droplets that escape the suction are absorbed and entrained in the ascending exhaust airflow, which then merges with the ventilation or circulation airflow provided in the room for infection prevention. As a result, this ascending exhaust airflow, which has been sterilized or inactivated to a certain degree , functions as an air curtain, preventing droplets from spreading to the seated person. This not only reduces or prevents the risk of aerosol infection caused by droplets remaining on the table, but also functions as a candlelight service item. This eliminates the need for large acrylic panels to separate seated people, and eliminates the feeling of oppression or claustrophobia that would be caused by the acrylic panels.

In addition, the rising exhaust airflow functions as an air curtain that prevents the spread of airborne droplets to people nearby. Any airborne droplets that escape suction are entrained in the rising exhaust airflow, which has been sterilized or inactivated to a certain extent by the sterilization means 5. In other words, they are blocked and can then be merged into the ventilation or circulation airflow provided in the room for infection prevention. This prevents droplets from scattering or spreading to people sitting opposite, and reliably prevents droplets from remaining suspended in the air for more than eight minutes after generation. By allowing airborne droplets to remain in the air above the table, the risk of infection from falling onto food or being inhaled can be reduced or prevented.

In addition, droplet receiving plates 6 extending in two to four directions are provided around the outer periphery of the casing 3, so that droplets generated from multiple directions when talking toward the intake and exhaust device 1 can be reliably caught by the partition function of the droplet receiving plates 6, even if there is an airspace where the airflow is weak, mainly between the intake port 31 and the exhaust port 32.Droplets that attempt to fall onto the table can be entrained in the surrounding suction flow and more reliably sucked in from the intake port 31.Furthermore, floating droplets that do not get sucked in can be reliably absorbed and entrained by the rising exhaust flow which functions as an air curtain, and can be processed to join the ventilation flow or circulation flow provided in the room for infection prevention.
Therefore, the suction efficiency into the air intake port 31 and the entrainment efficiency into the rising exhaust flow can be improved, the fluidization of air on the table is promoted, and even if a sterilization means 5 is not provided, dispersion to the opposite seating companion can be reliably prevented, the dispersion prevention effect can be enhanced, and the risk of infection caused by droplets remaining on the table can be further reduced or prevented.

Furthermore, by providing the exhaust port 32 with an exhaust flow-forming cap 7, which has outlets 32a and 32b formed in a shape that narrows the outlet shape, an upward exhaust flow shape that functions as an air curtain is generated. As the exhaust gas passes through the narrow outlets 32a and 32b, the flow velocity of the exhaust flow increases, imparting momentum to the upward exhaust flow and causing it to be ejected, improving its function as an air curtain. Furthermore, by adjusting the flow velocity and exhaust volume of the exhaust gas in relation to the suction force control of the blower fan 4, the air curtain can efficiently absorb and entrain airborne droplets, preventing them from scattering toward the opposing attendees. While the outlets 32a and 32b are formed in a cross shape, this is not limited to this and any other shape, such as a perforated plate, may also be used.

The sterilization means 5 is an ultraviolet sterilization lamp 51 that emits ultraviolet light with a wavelength that does not adversely affect human skin or eyes. The ultraviolet sterilization lamp 51 is configured to sterilize the inhaled droplets passing through the gas flow path by thermal sterilization using the heat generated by lighting the lamp, and to sterilize non-contact droplets by ultraviolet sterilization through irradiation.
This configuration effectively utilizes the heat generated by the ultraviolet germicidal lamp 51 itself (e.g., approximately 40-60°C) to achieve a thermal sterilization effect by contact with inhaled droplets passing through the gas flow path of the casing 3. In addition, strong ultraviolet light (UV illuminance) can be quantitatively irradiated at a short irradiation distance and at a closer distance to gas containing viruses and the like passing through the narrow air passage with the inner peripheral wall of the casing 3. This configuration also efficiently achieves combined sterilization and inactivation, including ultraviolet light irradiation taking into account the atmospheric temperature inside the casing 3 and thermal contact, including for droplets adhering to the inner wall of the casing 3. Furthermore, the efficiency of sterilization and inactivation by irradiation can be improved for airborne droplets accompanying the gas discharged from the exhaust port 32 and the ascending exhaust flow, while allowing the gas to be merged with the ventilation flow or circulation flow provided in the room for infection prevention.

The sterilization means 5 uses an electric heater 52 to sterilize suction droplets passing through the gas flow path. The electric heater 52 heats contact droplets via a preset temperature setting, while non-contact droplets are sterilized at the ambient temperature within the casing. The electric heater 52 can be selected from a variety of heaters, including sheath heaters that can be bent freely, sheet-shaped silicone rubber heaters and sheet heaters that are highly flexible and can be wrapped around curved or cylindrical surfaces to perfectly fit the object being heated, and cord-shaped silicone cord heaters. Contact efficiency can also be enhanced by forming the surface of the electric heater 52 into an uneven surface. The temperature of the electric heater 52 can be easily adjusted using a temperature controller based on an arbitrary setting that takes into account the ambient temperature and sterilization efficiency within the casing 3, allowing for greater manufacturing flexibility. The temperature within the casing 3 is also cooled by a blower fan 4, preventing it from rising above a certain temperature.

1 Intake and exhaust device 2 Base 3 Casing 3a Universal joint 31 Intake port 31a Intake port 32 Exhaust port 3b Connecting ring 3b1 Protrusion 3c Mounting holder 4 Blower fan 41 Double shaft motor 42a Blade body 42b Blade body 4a Blower fan 4a1 Motor 4a2 Blade body 4b Blower fan 4b1 Motor 4b2 Blade body 5 Sterilization means 51 Ultraviolet sterilization lamp 52 Electric heater 6 Droplet receiving plate 61 Mounting portion 62 Set hole 71 Discharge flow forming cap 32a Outlet 711 Round hole 712 Slit hole 713 Guide portion 72 Discharge flow forming cap 32b Outlet 721 Long hole

Claims (3)

An intake and exhaust device that includes a heat-generating sterilizing means and a blower fan inside a casing, and that draws in gas from an intake port formed on the lower side of the casing and exhausts the gas from an exhaust port on the upper side,
The suction and exhaust device is formed into a cylindrical shape so that it can be placed upright on a table that can accommodate multiple people,
The intake port is formed on the outer peripheral surface area of the casing so as to be able to draw gas from multiple directions , and the exhaust port is formed by opening it .
The sterilization means is disposed in the gas flow path between the intake port and the exhaust port on the inner peripheral wall surface of the casing , and a narrow ventilation area is formed between the inner peripheral wall surface and the sterilization means, thereby configuring the sterilization area ,
With the intake and exhaust device placed upright on a table, the gas on the table, which is the peripheral space of the device, is fluidized by generating a peripheral intake air flow that flows toward the intake port from multiple directions of the casing and an ascending exhaust air flow that flows out from the exhaust port,
Furthermore, the rising exhaust flow is generated by sucking gas from the intake port with a suction force capable of functioning as an air curtain and discharging the gas from the open exhaust port, thereby imparting momentum to the rising exhaust flow and generating it so that it can be ejected,
Droplets from multiple directions that occur during conversations on the table are immediately sucked in through the air intake , and the sucked droplets are sterilized and/or inactivated to a certain extent by heat sterilization due to contact with the sterilization means and the atmospheric temperature inside the casing due to heat generated by the sterilization means when passing through the sterilization area inside the casing, and then discharged;
A droplet spread prevention system characterized by entraining any airborne droplets that have escaped suction into the ascending exhaust flow along with the discharge of the treated suction droplets , and merging them into the ventilation flow or circulation flow provided in the room for infection prevention. 2. A droplet diffusion prevention system according to claim 1, characterized in that an exhaust flow forming cap having an outlet formed in a shape that narrows the opening of the exhaust port is provided on the exhaust port, thereby generating an exhaust flow shape of the ascending exhaust flow. In claim 1 or 2 , the sterilization means is an ultraviolet sterilization lamp that emits ultraviolet light that does not adversely affect human skin or eyes, or an electric heater, and the suction droplets that pass through the gas flow path are sterilized by the sterilization means, while non-contact droplets are sterilized by the ambient temperature inside the casing due to the heat generated by the sterilization means.