JP5261046B2 - Influenza infection prevention clean booth and virus infection prevention method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infection prevention booth for reliably suppressing infection of influenza by a relatively simple structure. <P>SOLUTION: The infection prevention booth includes: an enclosing body for forming a clean booth having a doorway in a building; an exhaust outlet provided on the enclosing body; an air blower having a blowing port for supplying an air flow which is purified through a filter and flows approximately in the horizontal direction to the exhaust outlet inside of a chamber of the clean booth; and a humidity adjusting device for keeping humidity inside the chamber of the clean booth at least at approximately 50% RH. A mist of particles containing influenza viruses dispersed from a fixed position for a patient in the chamber of the clean booth is discharged from the exhaust outlet to the outside of the chamber of the clean booth after being retained in the chamber of the clean booth for a period exceeding approximately 3 seconds. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention is an infection prevention booth that is installed in medical institutions, care welfare facilities, dental clinics, etc. for the purpose of accommodating pathogen holders such as bacteria and viruses or for medical personnel to examine them. In particular, the present invention relates to an infection prevention booth suitable for accommodating or examining a patient infected with influenza.

  As an aseptic treatment room unit for accommodating a carrier patient, a double structure unit inside and outside is installed in the room, and a space for accommodating a bed for a carrier is formed by the inner unit, and a high performance filter is formed in the space. And the air in the space is led to a high-performance filter through a negative pressure region between the inner unit and the outer unit, and the sterile treatment room unit is set through the filter. (See, for example, Patent Document 1).

  According to such an aseptic treatment room unit, since the space for accommodating the carrier is covered with a negative pressure region formed between the inner and outer units, the patient from the patient accommodated in the space The pathogenic bacteria can surely be prevented from leaking into the room where the treatment room unit is arranged. Therefore, by using such an aseptic treatment room unit as an influenza infection prevention booth and examining a patient who seems to be an influenza patient in the booth, it is possible to reliably prevent influenza infection in the facility.

  However, the treatment room unit as described above requires a double unit structure, and the structure is complicated.

Japanese Patent Laid-Open No. 9-222247

  Therefore, an object of the present invention is to provide an infection prevention booth that can reliably suppress influenza infection with a relatively simple configuration.

  Prior to the construction of the present invention, the basic principle of the present invention will be described. In order to prevent influenza virus infection, wearing a mask, especially wearing a mask that meets the National Institute of Occupational Safety and Health (NIOSH) N-95 standard (capable of collecting 95% or more test particles of 0.3 μm or more). It is considered valid. However, the particle collection performance of the filter media of these masks depends on the diameter of the fibers constituting the filter medium, but for particles of about 0.1 μm to less than 0.4 μm, regardless of the fiber diameter. It is known that sufficient collection performance cannot be exhibited.

  FIG. This is a graph of filter characteristics published in “Aero Zoro Technology” by Hines, written by Kazuya Hayakawa, Inoue Shoin, p. The graph is a graph showing the relationship between the particle diameter (μm) of the collected matter by the filter and the filter efficiency (%) using the diameter (μm) of the fiber used for the filter as a parameter, μm) and the vertical axis (%). Characteristic lines 1, 2 and 3 show the characteristics when the filter fiber diameter df is 0.5 μm, 2 μm and 10 μm, respectively. The filling rate of the filter was 0.05, the surface speed was 10 cm / s, and the filter thickness of each filter was set to a value indicating a predetermined equal pressure drop. Also from this graph, it can be seen that the collection performance for particles having a particle size in the range of about 0.1 to 0.4 μm is significantly reduced.

  Influenza viruses are approximately 0.1 μm in size. Therefore, the filter medium constituting the filter of the mask described above is aerosol particles, that is, fog particles that are 0.1 μm or more and less than 0.4 μm inclusive of influenza virus that is released from the patient due to sneezing or coughing of the patient that is the source of the virus. It is known that a sufficient mask effect cannot be exerted on particles having a shape.

  In addition, “Airborne micro-organisms survival test with four viruses” by Haper G. J, J. Hyg. Camb. (1961) 59, 479-489 reports that influenza is not prevalent in hot and humid summers. Yes.

  According to the inventors of the present application, further, under a relative humidity exceeding 50% RH, the particle size distribution of the aerosol particles containing active influenza virus is extremely short, and the distribution ratio decreases as the particle size decreases. It has been found.

  The present invention utilizes the above-described new knowledge about the particle size distribution including this active influenza virus, in addition to the conventional knowledge of influenza virus related to the characteristics of the above-described influenza virus mask and relative humidity of the influenza virus, Provided is a simple clean booth that does not release a virus such as an influenza virus contained in a particle size easily passing through a mask.

  More specifically, among influenza viruses floating in the air, in an environment with a relative humidity of 50% or more, a particle size of about 0.4 μm or more, which is a particle size large enough to be captured by a mask. The activity of influenza virus contained in the aerosol particles is not lost. However, the influenza virus contained in aerosol particles having a particle size of 0.1 to 0.4 μm that passes through the mask loses its activity after about 3 seconds in an environment with a relative humidity of 50% or more. For this reason, for example, the infectious titer of influenza virus contained in microparticles that cannot be reliably removed with a mask that satisfies the N-95 standard is significantly reduced under the circumstances described above. The present invention utilizes this principle.

That is, the virus infection prevention clean booth according to the present invention includes an enclosure for forming a clean booth having an entrance in a building, an exhaust port provided in the enclosure, and a filter in the clean booth. A blower having a blower port for supplying a flow of air that has been purified and flows in a substantially horizontal direction toward the exhaust port, and the humidity in the clean booth room is maintained at about 50% RH or more. The enclosure includes a peripheral wall portion provided with the doorway and a ceiling portion, divides a space on the floor of the building, and the air outlet of the blower is the clean air to blow out the air flow from the floor booth interior into a substantially horizontal direction at a predetermined height region is formed in a predetermined height position of the peripheral wall portion, for patients of the clean booth chamber Atomized particles comprising an influenza virus scattered from position, characterized in that it is discharged into the clean booth outside from the exhaust port after residence time of greater than about 3 seconds with the clean booth chamber.

  According to the clean booth according to the present invention, when aerosol particles containing influenza virus are released from the mouth of the patient at the fixed position in the clean booth, for example, together with cough or sneeze, After staying in the clean booth maintained at a humidity of 50% RH or more for about 3 seconds, it is discharged from the exhaust port to the outside of the clean booth. Among the aerosol particles containing the influenza virus released in this clean booth, the activity of the influenza virus contained in the aerosol particles having a particle diameter of about 0.4 μm or more captured by the mask is not lost, Influenza virus contained in aerosol particles of at least 0.1 μm or more and less than 0.4 μm loses activity in the clean booth. As a result, the infectious value of influenza virus contained in aerosol particles that are released from the exhaust port of the clean booth and cannot be captured by a mask is significantly reduced.

  For this reason, in an environment outside the clean booth, as long as a mask is attached, infection by influenza viruses contained in aerosol particles discharged from the clean booth outlet can be effectively prevented.

  Therefore, according to this invention, a clean booth can be comprised with the enclosure of a comparatively simple structure, without employ | adopting a double structure unit body.

  If the speed of the air flow from the blower is Nm / second, the horizontal distance from the fixed position to the exhaust port can be set to a value exceeding Nm / second × 3 seconds.

  The fixed position can be set in an air flow path from the air blowing port toward the exhaust port in the clean booth room.

The enclosure can be configured with a hood .

  The entrance / exit can be provided on the side of the peripheral wall opposite to the air outlet. Further, a door for opening and closing the doorway can be arranged at the doorway. In this case, the lower edge of the door can be spaced from the floor, and the space can be used as the exhaust port. For example, a flexible sheet member such as a vinyl sheet is used as the door, and the doorway can be opened and closed by winding and unwinding the sheet member. Instead, an interdigital flexible sheet member can be used. In addition, various forms can be adopted as the door. For example, depending on the relationship between the distance between the fixed position and the doorway and the blowing speed from the air outlet, the door is unnecessary and the doorway can be left open.

  The peripheral wall portion may include four peripheral wall portions that rise from the floor so as to define a rectangular bottom surface on the floor. In this case, the air blowing port may be provided in one of the peripheral wall portions of the set of the peripheral wall portions facing each other, and the exhaust port may be provided in the other peripheral wall portion of the set of the peripheral wall portions. The other set of the peripheral wall portions facing each other can be held so that the lower edge thereof is spaced from the floor by a predetermined distance. By installing the peripheral wall portion so that the lower edge of the other set of peripheral wall portions is spaced from the floor, there is no need to directly fix the lower edge of the peripheral wall portion to the floor. Similarly to the above, it is possible to easily install the peripheral wall portion. The space between the lower edge and the floor is set appropriately with respect to the air blown from the blower opening, so that the influence of the inflow and outflow of air between the inside and outside of the clean booth passing through the space is substantially reduced as will be described later. Can be eliminated.

  The ceiling height in the clean booth is preferably 1.8 m or more from the floor in consideration of the height of the patient or doctor in the clean booth. It is preferable that the upper end of the air outlet reaches the ceiling height of the clean booth. In consideration of the case where the patient is an infant, it is preferable that the lower end of the air outlet is about 80 cm or less from the floor. This is because the infant in the fixed position has a lower mouth position for sneezing or coughing than an adult. However, by setting the lower end of the air blowing port to be approximately 80 cm or less from the floor, it is possible to reliably guide the aerosol particles released together with the sneezing or coughing caused by the infant to the discharge port by blowing air from the air blowing port. Because it can.

  The height position of the lower edge of the other set of the peripheral wall portions may be positioned lower than a height position that is about 10 cm higher than the height position of the lower end of the air outlet. In the region of about ± 10 cm from the height position of the lower edge, a slight air suction action from the outside of the clean booth into the clean booth is observed due to the action of the air flow blown out from the blower opening. The cleanliness in the region below −10 cm from the height position of the lower edge is almost equal to the cleanliness outside the booth. However, in the above-described region, the cleanliness in the clean booth is not substantially lowered by the suction action so that the patient in the fixed position is affected by the germs outside the clean booth. Further, in the height region that is 10 cm or more lower than the lower edge in the clean booth, even if the cleanliness is further lowered, as long as the patient in the stereotaxic position in the clean booth does not take a posture that lies on the floor. The patient breathes in a clean air flow region above +10 cm above the height of the lower edge. Therefore, the patient in the clean booth is not substantially affected by the atmosphere in the region 10 cm or more below the air flow region in the clean booth.

  In the clean booth room, a patient chair and a doctor chair that define the home position can be arranged. The doctor chair is preferably located upstream of the patient flow than the patient chair. Thereby, it is possible to prevent the aerosol released from the patient due to the patient's coughing or sneezing from going directly to the doctor. In this regard, the distance between the chairs is desirably 90 cm or more, but is preferably approximately 90 cm in consideration of the state of treatment.

  A seating position for arranging at least the patient chair on the peripheral wall portion or the floor can be displayed using, for example, paint or color tape. The seating position is set so that a horizontal distance from the seating position to the exhaust port exceeds a product of an average air velocity (every second) of airflow from the blower port to the exhaust port and 3 seconds. Can do.

  Deflection means may be provided on the ceiling of the clean booth for deflecting downward a part of the air flow between the sitting position of the patient and the sitting position of the doctor.

  The deflecting means may be a hanging wall that hangs down from the ceiling. The lower end of the hanging wall is preferably 20 cm or more lower than the ceiling surface of the clean booth and 150 cm or more higher than the floor surface of the clean booth.

  As the filter, a filter having a performance capable of collecting 99% or more of suspended particles having a diameter of 0.3 μm can be used. A representative example of such a filter is a HEPA filter (High Efficiency Particulate Air Filter).

  The air blowing port can be connected to an air supply port provided in the ceiling of the building room via a duct. In this case, the air whose humidity has been adjusted can be supplied into the clean booth through the air supply port.

  The humidity is preferably about 70% RH or less. That is, in consideration of human comfort, it is desirable to set the humidity within a range of about 50% RH to about 70% RH.

  The temperature in the clean booth is maintained between 15 ° C. and 30 ° C., more preferably between 15 ° C. and 25 ° C.

  According to the method of the present invention, as described above, the clean booth can be constituted by a relatively simple enclosure without having a double structure unit, so that the influenza can be reliably ensured by wearing a mask. An infection prevention booth that can suppress infection can be easily formed.

  Prior to describing the examples of the present invention, an experiment for determining the mist particle size dependence of inactivation of airborne influenza virus will be described with reference to FIG. This experiment was performed in a cubic virus experiment booth 12 (2000 mm × 2000 mm × 2000 mm) formed by the vinyl enclosure 10 as shown in FIG. The vinyl enclosure 10 is provided with an open / close chuck 14 for allowing entry into and exit from the virus experiment booth 12.

According to the guidelines of the National Institute of Infectious Diseases, influenza viruses should be handled in a biosafety level 2 clean space where negative pressure is secured. In order to satisfy this standard, purified air having passed through a fan-equipped air cleaner 16 equipped with a hepa (HEPA) filter is supplied into the virus experiment booth 12, and the experiment booth 12 has an intake pipe provided with a HEPA filter 12a. The exhaust pipe 12e provided with the HEPA filter 12d and the vacuum exhaust pump 12c was connected. The negative pressure in the experiment booth 12 was maintained by the operation of the vacuum pump 12c (atmospheric discharge capacity of about 10 liters / minute). Further, in the virus experiment booth 12, a far-infrared heater 18 is disposed as a heating or heating means and an ultrasonic humidifier 20 is disposed as a humidifying means for temperature adjustment and humidity adjustment in the booth. Both of these means 18 and 20 were controlled to operate based on the detection value of the temperature / humidity sensor 22 in order to maintain the room temperature and humidity at predetermined values. Furthermore, the temperature and humidity in the virus experiment booth 12 were maintained at a predetermined uniform value by the air stirring action of the stirring fan 24 arranged in the virus experiment booth 12. The effective volume excluding the volumes of these devices 16 to 24 in the virus experiment booth 12 was approximately 7.2 m ³ .

  In the virus experiment booth 12, the floating virus carrying tube 26, a virus sprayer (nebulizer) 28 disposed at one end of the floating virus carrying tube, and a multistage classifier 30 connected to the other end of the floating virus carrying tube 26. And a suction pump 32 connected to the multi-stage classifier.

  As the floating virus carrying tube 26, a stainless steel tube having a diameter of 100 mm and a length of 500 mm and having both ends opened was used. The virus sprayer 28 sprays the mist of the virus solution containing the influenza virus (the particle diameter is 10 μm or less) from one end of the stainless tube 26 toward the other end. The suction pump 32 sucks the air in the virus experiment booth 12 through the multistage classifier 30 together with the mist of virus liquid from the virus sprayer 28. The suction pump 32 was operated so that the amount of air passing through the floating virus carrying tube 26 having a length of 500 mm was 80 liter / min and the wind speed inside the floating virus carrying tube 26 was 17 cm / sec. Therefore, the mist of the virus liquid sprayed from the virus sprayer 28 at one end of the floating virus carrying tube 26 reaches the other end of the floating virus carrying tube 26 after about 3 seconds (500 ÷ 170), The connected multi-stage classifier 30 is reached. The passing air amount, temperature, humidity, and the like were measured between the outlet that is the other end of the floating virus carrying tube 26 and the inlet of the multistage classifier 30.

As the virus sprayer 28, a compressor type nebulizer NE-C16 manufactured by OMRON Corporation was used. Moreover, the virus liquid sprayed from the virus sprayer 28 is a liquid obtained by growing a virus using the hen's egg urine urine membrane cavity, and influenza (A type) is contained in a liquid called urine urine. A / Aich / 2/68 (H3N2)). This liquid has a protein concentration of about 1 wt%. The concentration of influenza virus contained in this virus solution was 5.5 × 10 ^{7 to} 16 × 10 ⁷ PFU (Plaque forming unit) / cc. The virus sprayer 28 sprayed the mist of the virus solution into the floating virus carrying tube 26 continuously for 15 seconds at a flow rate of 1 μl (0.001 cc) per second.

  The mist of the virus liquid sprayed from the virus sprayer 28 at one end of the floating virus carrying tube 26 is evaporated and dried almost instantaneously and travels to the other end of the floating virus carrying tube 26. It reaches the classifier 30 and is collected by the multi-stage classifier.

  As the multi-stage classifier 30, “The Next Generation Pharmaceutical Impactor” manufactured by MSP Corporation of the United States was used. This multi-stage classifier 30 is a kind of inertial impactor similar to the under-sensor pan. The multi-stage classifier 30 comprising the impactor has an internal volume of 1 liter, and the time for an air flow of 80 liters / min to pass through the multi-stage classifier 30 is 0.0125 seconds. The particle size range to be classified is 0.06 μm or less, 0.06 to 0.26 μm or less, 0.26 to 0.45 μm or less, 0.45 to 0.78 μm or less in the case of an air flow of 80 liters / min. It is divided into 9 stages ranging from 0.78 to 1.4 μm or less, 1.4 to 2.3 μm or less, 2.3 to 3.8 μm or less, 3.8 to 6.7 μm or less, and over 6.7 μm. It was. Special filtration called a gelatin membrane filter having a performance of capturing 98.7% or more of particles having a minimum classification range of 0.06 μm or less, which is smaller than 0.06 μm, regardless of the particle size. The material was collected by attaching it to the outlet of the multi-stage classifier 30.

  FIG. 3 shows the activity of the multistage classifier 30 when the humidity in the virus experiment booth 12 is changed in a state where the room temperature in the virus experiment booth 12 is maintained at 15 ° C., 20 ° C., 25 ° C. and 30 ° C., respectively. It is a graph which shows the relationship with the collection rate of influenza virus.

  The horizontal axis of the graph of FIG. 3 represents relative humidity (% RH), and the vertical axis represents the recovery rate (%). The recovery rate (%) is a multi-stage classifier with the infectivity titer of all viruses sprayed for 15 seconds continuously at a flow rate of 1 μl (0.001 cc) per second from the virus sprayer 28 into the floating virus transport tube 26 as 100. The percentage of infectivity of all viruses recovered at 30 is shown in%. Characteristic lines 34a, 34b, 34c, and 34d in the graph indicate the recovery rates when the relative humidity (% RH) is changed while the environmental temperature is maintained at 15 ° C, 20 ° C, 25 ° C, and 30 ° C, respectively. (% RH) changes.

  According to the characteristic line 34a of the graph, for example, when the room temperature is maintained at 15 ° C., the recovery rate is about 25% under a relative humidity of 20%. It shows that about 75% of all viruses supplied to the transfer tube 26 have been inactivated. For each of the characteristic lines 34a to 34d, except for the characteristic line 34b, the inactivation ratios shown by the characteristic lines 34a to 34d change at 60% and 70% relative humidity. However, considering the variation in each situation or measurement error between experiments, it can be said that about 70% or more of the influenza virus is inactivated regardless of the temperature from the tendency of the characteristic lines 34a to 34d. In addition, the virus recovery rate does not change greatly with changes in relative humidity, and the infectivity of all recovered viruses is almost constant regardless of changes in relative humidity. It can be said that the amount of modified virus does not decrease or increase with changes in relative humidity.

  The graphs shown in FIGS. 4 to 7 are collected by the multi-stage classifier 30 when the relative humidity (% RH) is changed with the room temperature held at 15 ° C., 20 ° C., 25 ° C., and 30 ° C., respectively. The particle size distribution of the particles is shown.

  For example, according to the graph of the particle size distribution at room temperature of 15 ° C. shown in FIG. 4, at relative humidity of 20, 30 and 40% RH, 0.06 μm or less, 0.06 to 0.26 μm or less, and 0.26 to In each particle range of 0.45 μm or less, there is no significant reduction compared to the distribution ratio of other particle ranges. On the other hand, in the relative humidity of 50, 60 and 70% RH in the graph, other particle ranges are 0.06 μm or less, 0.06 to 0.26 μm or less, and 0.26 to 0.45 μm or less. A significant reduction is seen in comparison with the distribution ratio.

  This tendency with a relative humidity of 50% RH as a boundary can also be seen in the graphs of FIGS. 5 to 7 showing particle size distributions at room temperature of 20 ° C., 25 ° C., and 30 ° C. Therefore, when the relative humidity exceeds 50%, the distribution ratio of particles less than 0.45 μm is drastically reduced. In addition, as described in detail below, the activity of influenza virus contained in aerosol particles having a particle diameter of about 0.4 μm or more that can be captured by a mask is not lost, but cannot be captured by a mask. Influenza virus contained in aerosols less than 4 μm is inactivated.

  From the above, influenza contained in aerosol particles having a particle diameter of about 0.4 μm or more captured by a mask by allowing an aerosol containing influenza virus to stay in an environment exceeding 50% RH for about 3 seconds. Although the virus activity is not lost, influenza viruses contained in aerosols of less than 0.4 μm that cannot be captured by a mask can be inactivated. Therefore, as long as the mask is attached, infection with influenza virus can be prevented.

  The following considerations were made regarding the drying of biological mists on the basis of 3 seconds or more. The time until the minute water droplets containing no impurities are completely dried is 0.06 in a temperature and humidity environment of 10 ° C. to 30 ° C. and 10% RH to 80% RH even if the droplets are 10 μm in size. Only 0.7 seconds. On the other hand, mist generated by coughing and sneezing is assumed to be saliva as the main component, and 99.5% of saliva components are water, and the remaining 0.5% are protein components and salts mainly composed of albumin. It is believed that there is. Therefore, in the case of mist generated by coughing or sneezing, it is expected that the drying dynamics are different from the minute water droplets containing no impurities.

  The difference in drying between saliva mist and water droplets that do not contain impurities is that the former is more difficult to evaporate than the latter because its vapor partial pressure decreases as the protein concentration increases due to evaporation. . Water that does not contain impurities will eventually evaporate completely, whereas saliva that contains impurities such as proteins will leave solid particles of protein as evaporation residues even if the water evaporates. is there.

  The inventors of the present application determined the relationship between the concentration of the protein solution, the temperature / humidity of the ambient atmosphere, and the vapor pressure through experiments. The graph of FIG. 8 shows the experimental results, the horizontal axis indicates the weight concentration (wt%) of protein mist containing protein, and the vertical axis indicates the vapor partial pressure (relative humidity) (% RH). ◯ is 30 ° C., ● is 25 ° C., Δ is 20 ° C., ▲ is 15 ° C. and □ is 10 ° C. The solid line is an approximate curve connecting them.

  According to the graph of FIG. 8, for example, a mist containing protein sprayed in air with a relative humidity of 80% RH is completely dried at a protein weight concentration of 30 wt% that balances with the surrounding water vapor partial pressure (80% RH). To do. That is, protein is 30 wt% and moisture is 70 wt%. On the other hand, the mist containing protein sprayed in air having a relative humidity of 40% RH is completely dried at a protein weight concentration of 90 wt% that balances the surrounding water vapor partial pressure (40% RH). That is, protein is 90 wt% and moisture is 10 wt%. As is clear from the above paper by Haper G. J, the floating influenza virus is lost when the water vapor partial pressure is 40% RH or more, in other words, when the protein weight concentration is 90 wt% or less or the water weight concentration is 10 wt% or more. It has characteristics that make it easy to use.

  The meanings of the graphs shown in FIGS. 4 to 7 are that the smaller the spray mist particle size, the shorter the drying time until equilibrium with the surrounding water vapor partial pressure becomes 0.45 μm or less at a floating time of 3 seconds. The small particles will dry to a protein weight concentration that is in equilibrium with the ambient vapor partial pressure. When the ambient vapor partial pressure is 40% RH or less, the infectivity value is maintained because the water concentration becomes 10 wt% or less in the floating time of 3 seconds. However, when the ambient vapor partial pressure is 50% RH or more, 3 seconds. Since the water concentration becomes 24 wt% or more in the floating time, the influenza virus is deactivated.

  At a suspension time of 3 seconds, particles over 0.45 μm are still in the process of drying and have not reached equilibrium with the ambient vapor partial pressure, so the influenza virus contained therein maintains the infectious titer. On the other hand, small particles of 0.45 μm or less reach equilibrium with the surrounding vapor partial pressure in a suspension time of 3 seconds, so that the influenza virus contained therein is surely inactivated at 50% RH or more. From this, the minimum floating time under an environment of 50% RH or more and a value of 3 seconds were determined.

  In order to inactivate influenza virus contained in particles exceeding 0.45 μm at 50% RH or more, it is conceivable to equilibrate with the surrounding vapor partial pressure by securing a floating time longer than 3 seconds. However, if the floating time is longer than 3 seconds, the booth length increases. If it is an infection prevention measure wearing a mask such as N-95 described above, it is practically unnecessary to deactivate the influenza virus contained in large particles exceeding 0.45 μm.

  The clean booth 50 according to the present invention is based on such knowledge, and is installed, for example, on a floor 52a of a hospital room 52 as shown in FIG. The clean booth 50 includes, for example, a rectangular enclosure 54 made of vinyl, for example, and a humidity sensor 56a (see FIG. 10) in the clean booth compartment 56 defined by the enclosure. A humidity adjuster 58 for adjusting the humidity and a blower 60 connected to the humidity adjuster 58 by a conduit 58a for purifying the air humidified by the humidity adjuster and supplying it to the clean booth room 56. Including.

  The envelope body 54 is made of a vinyl hood disposed so as to cover the frame body 62 having a length L, a width W, and a height H of 2.5 m, 1.0 m, and 2.0 m, respectively. The enclosure 54 basically includes a rectangular ceiling portion 54a, a pair of side wall portions 54b and 54b along the long side of the ceiling portion, and a pair of end wall portions 54c along the short side of the ceiling portion 54a. 54c. In the illustrated example, the lower edge of the enclosure 54 does not contact the floor 52a and is spaced from the floor by a predetermined height dimension h1, for example, 80 cm.

  The pair of side wall portions 54 b and 54 b and the pair of end wall portions 54 c and 54 c constitute a peripheral wall portion of the enclosure 54. In the illustrated example, one end wall portion 54c is replaced with a blower opening 60a of the blower 60, and a filter 64 is attached to the blower opening. The other end wall portion 54 c is used as a door (54 c), and the door 54 c opens and closes the entrance / exit 50 a of the clean booth 50.

  As shown in FIG. 9, the air outlet 60a has a width dimension that matches the width W of the end wall portion 54c of the enclosure 54, and as shown in FIG. The upper end has a rectangular planar shape that reaches the ceiling portion 54a, that is, the ceiling. In the illustrated example, the lower end of the blower opening 60a is set to a height of 80 cm from the floor 52a as described above.

  The filter 64 has a rectangular planar shape arranged so as to cover the air blowing port 60a, and therefore, the lower end thereof is located at a height of 80 cm from the floor 52a. The filter 64 is formed of a particle removal filter such as the HEPA filter described above.

  The blower 60 takes in the air in the hospital room 52 in which the clean booth 50 is installed by its operation, adjusts the humidity of this air by the humidity adjuster 58, and is further incorporated in the blower 60 as necessary. Do not adjust the temperature with a temperature regulator. Thus, the blower 60 supplies the adjusted air as purified air into the clean booth chamber 56 through the filter 64.

  The filter 64 is installed so as to cover the region of the one end wall portion 54c. Therefore, by the operation of the blower 60, the filter 64 is almost uniform in the horizontal direction toward the door 54c in the region from the ceiling 54a to the lower edge of the side wall 54b as shown in FIG. A purified air stream is ejected. This purified air flow acts almost uniformly over almost the entire width of the clean booth chamber 56.

  The lower edge of the door 54c to which the purified air flow is directed is spaced from the floor 52a by a height dimension h1 with the doorway 50a closed, and an exhaust port 66 is formed by this space. Accordingly, the purified air flow ejected from the filter 64 toward the door 54c is exhausted into the hospital room 52 from the exhaust port 66 located below the door when the door 54c is closed.

  In order to use the clean booth room 56 as an examination area, as shown in FIG. 10, the clean booth room 56 includes a chair 68 a for a patient 68 and a chair 70 a for a doctor 70. They are spaced from each other in the direction of the flow.

The patient chair 68a is arranged on the downstream side of the purified air flow compared to the doctor chair 70a, and the chairs 68a and 70a are arranged facing each other so that the patient 68 and the doctor 70 can face each other. Has been. In the example shown in FIG. 10, a mark 72 that defines the position of the patient chair 68a is formed on the floor 52a. The horizontal distance l ₁ of the mark 72 from the exhaust port 66 along the flow direction of the purified air flow is set to a value of Nm / second × 3 seconds or more when the average flow velocity of the purified air flow is Nm / second. Has been.

  The patient chair 68 a is arranged at a position where a virtual vertical line that will pass through the position of the mouth of the patient 68 sitting on the chair approximately intersects the mark 72 with the mark 72 as a mark. Instead of providing the mark 72 on the floor 52a, or in addition to the floor 52a, the mark 72 can be provided on the side wall portion 54b. Further, the mark 72 is not required, and the chair 68a can be fixed to be removable at the predetermined position.

  The scattering time to the maximum distance that fine particles reach by sneezing is 0.2 to 0.5 seconds under no wind (Nishimura et al. “Analysis of activity of aerosol particles by sneezing and influenza virus in airborne aerosols”, 25th Considering that it is a rejuvenated air purification and contamination control tournament rehearsal collection p81-83, 2007), the distance between the chairs 68a, 70a is preferably 90 cm or more. Thereby, it is possible to prevent fine particles accompanying coughing or sneezing of the patient 68 sitting on the chair 68a from directly reaching the doctor 70 sitting on the chair 70a. Of course, the doctor 70 sitting on the chair 70a preferably wears a mask.

In the above-described clean booth 50, the temperature of the clean booth chamber 56 is maintained at an appropriate temperature between 20 ° C. and 25 ° C., and the humidity is between 50% RH and about 70% RH in order not to significantly impair comfort. Thus, the average flow rate of the purified air flow through the HEPA filter 64 was maintained at an appropriate relative humidity, and was about 30 cm / second. The cleanliness of the clean booth chamber 56 at this time is class 100 (1 m ³⁾ which is clean enough to be used as a clean booth according to a measurement using a laser particle counter (KR-12A manufactured by Rion Co., Ltd.). In the air, about 100 particles having a size of 0.1 μm or more are contained.). In this case, the horizontal distance l ₁ of the mark 72 from the exhaust port 66 is set to 90 cm.

  When the patient 68 sitting on the chair 68a sneezes or coughs under the environment in the clean booth 50 as described above, the aerosol with influenza virus is released from the patient 68 into the clean booth room 56. The aerosol flows on the purified air flow toward the exhaust port 66 and flows toward the exhaust port 66. Therefore, the aerosol does not leak into the hospital room 52 from the gap h1 between the lower edge of the enclosure 54 and the floor 52a while reaching the exhaust port 66, and is reliably guided to the exhaust port 66 from the exhaust port 66. It is discharged into the hospital room 52.

  Therefore, since the aerosol discharged from the patient 68 is placed under a high humidity of 50% RH or more over 3 seconds, as described above, some of the influenza contained in the aerosol is inactivated. . Moreover, since the influenza virus contained in the aerosol of less than 0.4 μm that cannot be substantially captured by the mask can be substantially inactivated, such aerosol is discharged from the exhaust port 66 to the hospital room outside the clean booth 50. Even if it is discharged to 52, infection of influenza virus to a person 74 (see FIG. 11) in the hospital room can be surely prevented as long as this person 74 wears a predetermined mask.

  Further, for example, a medium performance filter whose particle removal performance is not high performance such as HEPA can be used for the filter 64. In such a case, it is particularly desirable to set the horizontal distance from the air outlet 60a of the blower 60 to the doctor's chair 70a to a value of Nm / second × 3 seconds or more. That is, as described above, when the average flow velocity of the purified air flow is about 30 cm / second, it is desirable to dispose the chair 70a at a distance of 90 cm or more from the air blowing port 60a. Thereby, in the position of the doctor 70 seated on the chair 70a, since the infectious titer of influenza virus contained in the air taken into the clean booth room 56 from the clean booth 50 through the filter 64 can be significantly reduced, Safety for the doctor 70 is improved.

  As shown by the phantom line 76a in FIG. 10, the lower edge of the enclosure 54, that is, the booth skirt is set 10 cm lower than the lower edge of the air outlet 60a, or at the lower edge of the enclosure 54 as shown by the phantom line 76b. The skirt of a certain booth was set 10 cm higher than the lower edge of the air blowing port 60a, and the cleanliness of the clean booth chamber 56 in the vicinity of the booth skirts 76a and 76b in each case was measured.

When the booth hem is set 10 cm lower than the lower end of the air outlet 60a, the cleanliness of the purified air flow region 80 cm or more from the floor 52a is equal to the case where the booth hem is matched with the lower end of the air outlet 60a. And achieved class 100. However, the cleanliness in the 70-80 cm height region from the floor 52a is class 100,000 (about 100,000 particles having a size of 0.1 μm or more are contained in 1 m ³ air). In the region, it was found that partial suction of air in the hospital room 52 into the clean booth room 56 occurred.

  Moreover, when the booth hem was set 10 cm higher than the lower end of the air outlet 60a, class 100 could be realized in an area of 90 cm or more on the floor that coincided with the booth hem. However, in the region from 10 cm below the booth hem, that is, 80 cm above the floor 52a to 90 cm above the booth skirt, ie, the floor 52a, the class was 100,000.

  From this, the mixing phenomenon of air from the outside of the clean booth 50 can be seen in the area 10 cm above and below the booth hem. The position can be set as appropriate in relation to the lower end position of the air blowing port 60a. Of course, the booth hem can be in contact with the floor 52a. However, as described above, it is preferable that the booth hem is spaced from the floor 52a in order to simplify the installation work of the clean booth 50.

  The upper end of the blower opening 60a of the blower 60 can be set so that it does not reach the ceiling and is located within 10 cm below the ceiling portion 54a. As a result, no substantial change was observed in the cleanliness in the clean booth 50.

  Further, as is apparent from the above, the aerosol from the patient 68 seated on the chair 68a is discharged out of the clean booth 50 after a time of 3 seconds or more even when the doorway 50a is opened. . This eliminates the need for the door 54c and allows the doorway 50a to be open. However, in this case, in order to maintain the humidity of the clean booth room 56 at 50% RH or higher, a large humidifying capacity is required by the humidity adjuster 58. Therefore, in order to reduce the capacity required for the humidity adjuster 58, it is desirable to provide the door 54c.

  FIG. 11 shows an example in which an air conditioner 80 set in the ceiling plenum chamber 78 of the hospital room 52 is used instead of the humidity controller 58 and the blower 60 of the clean booth 50 shown in FIG.

The air conditioner 80 has, for example, a temperature adjustment function for adjusting the temperature of air sucked from the ventilation port 84 provided in the ceiling 82 of the hospital room 52 having a space volume of 50 m ³ and a function for adjusting the humidity. A part of the air whose temperature and humidity are adjusted is returned to the hospital room 52 through the first air supply port 86. The remaining portion of the air whose temperature and humidity are adjusted is supplied from the second air supply port 88 through the duct 90 to the blower port 60a provided with the filter 64.

The air conditioner 80 has, for example, a maximum air volume of 30 m ³ / min, and has an ability to convert air at 20 ° C. and 30% RH into air at 22 ° C. and 50% RH, for example. By the operation of the air conditioner 80, purified air of, for example, 20 ° C. and 50% RH can be supplied from the filter 64 to the clean booth chamber 56 at an average speed of about 30 cm / second, for example. Therefore, the air conditioner 80 acts as the humidity adjuster 58 and the blower 60 described above.

  FIG. 12 shows an example in which a hanging wall 92 is provided in the clean booth 50 shown in FIG. 10 so as to hang down from the ceiling 54 a between the patient 68 and the doctor 70. In the example of FIG. 9 in which the drooping wall 92 is not provided, the cleanliness in front of the mouth of the doctor 70 was measured using a laser particle counter 94 as shown in FIG. As shown in FIG. 13, since the doctor 70 seated on the chair 70a receives the horizontal air flow from the air blowing port 60a from the back, an air stagnation area 96 is formed in front of the mouth of the doctor 70, and the stagnation It is considered that air outside the clean booth 50 may be caught in the area from between the floor 52a and the lower end of the side wall portion 54b of the enclosure 54 as the doctor 70 moves.

  In order to eliminate the stagnation region 96, a drooping wall 92 shown in FIG. 12 is provided. The drooping wall 92 generates a downward air flow in front of the mouth of the doctor 70 in a part of the horizontal air flow in the clean booth room 56. Due to the deflection action of the drooping wall 92, according to the measurement of the laser particle counter 94, it was possible to always maintain the cleanliness of the class 10 level in the area in front of the mouth regardless of the movement of the doctor 70.

  The hanging wall 92 can be formed of a plate member. It is desirable that the lower end of the hanging wall 92 is located in a range between 20 cm or less from the ceiling portion 54a and 150 cm or more on the floor surface 52a. Accordingly, it is possible to effectively prevent the occurrence of the stagnation region 96 without interfering with the exercise accompanying the medical examination of the doctor 70.

  The drooping wall 92 is more desirable in that it can be moved between 68 and the doctor 70 along the horizontal direction of the air flow so that the dripping wall 92 can be moved to a position that does not interfere with the examination. . Further, in place of the hanging wall 92, various deflecting means for preventing the occurrence of stagnation 96 can be provided in addition to the deflecting means composed of a synthetic film such as vinyl or a hanging curtain such as cloth. In order to prevent injury or breakage when a doctor or patient accidentally collides with the drooping wall, it is desirable that it naturally jumps toward the ceiling at the time of collision as shown in FIG.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the door 54c can have various open / close door structures such as a roll-up type and an accordion type. In addition, the material, shape, dimensions, and the like of the enclosure 54 are not limited to the above example, and can be selected as appropriate. In addition to the HEPA filter described above, a filter equipped with various filter media that can reliably capture particles of 0.45 μm or more can be used as the filter. Further, the average flow velocity of the purified air flow can be variously changed depending on the size of the clean booth 50 as long as the patient 68 and the doctor 70 are not uncomfortable.

  Further, in the above description, the clean booth 50 is used as a diagnostic booth. However, the clean booth is used as a patient accommodating booth by arranging a patient bed (not shown) instead of the patient chair 68a. Can do.

The relationship between the capture particle size of suspended particles when the filter diameter of the filter (d _f) as parameters and ([mu] m) Capture efficiency (%), respectively a graph showing the horizontal and vertical axes. It is a schematic diagram which shows roughly the experimental apparatus for calculating | requiring the mist particle diameter dependence of airborne influenza virus inactivation. The experimental result using the experimental apparatus shown in FIG. 2 is shown, and the relationship between the environmental relative humidity (% RH) and the recovery rate of active influenza virus (%) when the environmental temperature is used as a parameter is shown on the horizontal axis and the vertical axis, respectively. It is a graph shown as. 2 shows the experimental results using the experimental apparatus shown in FIG. 2, and the particle diameter (μm) after suspending a mist containing active influenza virus for 3 seconds when relative humidity is a parameter with the environmental temperature maintained at 15 ° C. And the relationship between the distribution ratio (%) and the vertical axis, respectively. 2 shows the experimental results using the experimental apparatus shown in FIG. 2, and the particle diameter (μm) after suspending mist containing active influenza virus for 3 seconds when the relative humidity is a parameter with the ambient temperature kept at 20 ° C. And the relationship between the distribution ratio (%) and the vertical axis, respectively. The experimental result using the experimental apparatus shown in FIG. 2 is shown, and the particle diameter (μm) after suspending mist containing active influenza virus for 3 seconds when relative humidity is used as a parameter while maintaining the environmental temperature at 25 ° C. And the relationship between the distribution ratio (%) and the vertical axis, respectively. The experimental result using the experimental apparatus shown in FIG. 2 is shown, and the particle diameter (μm) after suspending the mist containing active influenza virus for 3 seconds when the relative humidity is a parameter while the environmental temperature is kept at 30 ° C. And the relationship between the distribution ratio (%) and the vertical axis, respectively. It is a graph which shows the relationship between protein mist weight concentration (wt%) and vapor partial pressure (relative humidity) (% RH) as a horizontal axis and a vertical axis, respectively. 1 is a perspective view schematically showing a clean booth according to the present invention. It is explanatory drawing which shows typically the clean booth which concerns on this invention. 11 is a view similar to FIG. 10 showing another clean booth according to the present invention. It is drawing similar to FIG. 10 which shows the other example of the clean booth which concerns on this invention. It is a typical explanatory view for explaining generation of stagnation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 50 Clean booth 52 Patient room 52a Floor 54 Enclosure 54a Ceiling part 54b Side wall part 54c Door 56 Clean booth room 58 Humidity regulator 60 Blower 64 Filter 66 Exhaust port 68a Patient chair 70a Doctor chair 72 Mark 80 Air conditioner 92 Deflection means (hanging wall)

Claims (15)

An enclosure for forming a clean booth having an entrance / exit in a building, an exhaust port provided in the enclosure, and an air flow purified through a filter in the room of the clean booth to the exhaust port A blower having a blower opening for supplying an air flow flowing in a substantially horizontal direction, and a humidity regulator for maintaining the humidity in the clean booth room at about 50% RH or more,
The enclosure includes a hood that has a peripheral wall portion provided with the doorway and a ceiling portion, and divides a space on the floor of the building,
The blower opening of the blower is formed at a predetermined height position of the peripheral wall portion so as to blow out the air flow in the horizontal direction in a predetermined height region from the floor into the clean booth room,
A mist-like particle containing influenza virus scattered from a fixed position for a patient in the clean booth room is discharged from the exhaust port to the outside of the clean booth room after a stay time exceeding about 3 seconds in the clean booth room. A clean booth that features virus infection prevention.   An enclosure for forming a clean booth having an entrance / exit in a building, an exhaust port provided in the enclosure, and an air flow purified through a filter in the room of the clean booth to the exhaust port A blower having a blower opening for supplying an air flow flowing in a substantially horizontal direction, and a humidity regulator for maintaining the humidity in the clean booth room at about 50% RH or more,
  The exhaust port is provided on the other wall facing the one wall of the enclosure in which the air blowing port is provided,
  The patient is located in the air flow path in the clean booth room from the air blowing port toward the exhaust port,
  Mist-like particles that cannot be captured by a mask containing influenza virus that scatters from a fixed position for a patient in the clean booth room are discharged from the exhaust port to the outside of the clean booth room after a stay time exceeding about 3 seconds. A clean booth for preventing virus infection, wherein mist-like particles from the patient ride on an air stream and are discharged from the exhaust port. When the speed of the air flow from the blower and Nm / sec, the horizontal distance from the home position to the exhaust port is set to a value greater than Nm / sec × 3 seconds, to claim 1 or 2 The virus infection prevention clean booth described. The virus infection prevention clean booth according to any one of claims 1 to 3 , wherein the fixed position is set in an air flow path from the blower port to the exhaust port in the clean booth chamber. The said enclosure has the surrounding wall part in which the said entrance / exit was provided, and the ceiling part, and consists of the food | hood for partitioning space on the floor of the said building, The any one of Claim 2 to 4 Virus infection prevention clean booth.   The doorway is provided on the side of the peripheral wall opposite to the air outlet, and a door for opening and closing the doorway is disposed at the doorway, and the lower edge of the door is spaced from the floor, The virus infection prevention clean booth according to claim 1, wherein the exhaust ports are formed at intervals. The peripheral wall portion includes four peripheral wall portions that rise from the floor so as to define a rectangular bottom surface on the floor, and the air blowing port is provided in one of the peripheral wall portions of a pair of the peripheral wall portions facing each other. The exhaust port is provided in the other peripheral wall portion of the peripheral wall portion of the set;
The virus infection prevention clean booth according to claim 6 , wherein a lower edge of another set of the peripheral wall portions facing each other is held at a predetermined distance from the floor. The ceiling height in the clean booth chamber is 1.8 m or more from the floor, and the upper end of the air blowing port reaches the ceiling height of the clean booth or is located within 10 cm below the ceiling, and the lower end of the air blowing port. Is located about 80 cm or less from the floor, and the height position of the lower edge of the peripheral wall portion of the other set is higher than the height position of about 10 cm from the height position of the lower end of the air outlet. The virus infection prevention clean booth according to claim 7 , which is located below. In the clean booth room, a chair for the patient that defines the fixed position and a chair for the doctor are disposed, and the chair for the doctor is disposed on the upstream side of the air flow with respect to the chair for the patient. The virus infection prevention clean booth according to claim 4 . A seating position for disposing at least the patient chair on the peripheral wall portion or the floor is displayed, and the seating position is a horizontal distance from the seating position to the exhaust port. The virus infection prevention clean booth according to claim 9 , which is set to have a value exceeding a product of an average wind speed (every second) of airflow to 3 seconds and 3 seconds. Wherein the ceiling of the clean booth, deflection means for providing deflection downward a portion of the air flow between the seating position of the seating position and the physician of the patient is provided, from claim 1 The virus infection prevention clean booth according to any one of 10 . The deflection means is a hanging wall that hangs down from the ceiling, and a lower end of the hanging wall is 20 cm or less from the ceiling surface of the clean booth and at a height of 150 cm or more from the floor surface of the clean booth. 11. A virus infection prevention booth according to 11 . The clean booth according to any one of claims 1 to 12, wherein the filter has a performance capable of collecting 99% or more of suspended particles having a diameter of 0.3 µm. The blower outlet being connected via a duct to the air supply port provided in the ceiling of the building chamber, supplied with the air which has been humidity-controlled via the air supply port, any one of claims 1 to 13 Clean booth described in 1.   An enclosure for forming a clean booth having an entrance / exit in a building, an exhaust port provided in the enclosure, and an air flow purified through a filter in the room of the clean booth to the exhaust port A virus infection prevention method in a virus infection prevention clean booth comprising a blower having a blower opening for supplying an air flow that flows in a substantially horizontal direction toward and a humidity regulator that maintains humidity in the clean booth room. ,
  Keep the humidity in the clean booth room from 50% RH to 70% RH,
  Maintain the temperature in the clean booth at 15 ° C to 30 ° C,
  A mist-like particle containing influenza virus scattered from a fixed position for a patient in the clean booth room is discharged from the exhaust port to the outside of the clean booth room after a stay time exceeding about 3 seconds in the clean booth room. A virus infection prevention method characterized.

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