Patent Publication Number: US-2022234038-A1

Title: Safety Cabinet

Description:
TECHNICAL FIELD 
     The present invention relates to a safety cabinet used for regenerative medical treatment such as cell preparation and research on pathogens or the like. 
     BACKGROUND ART 
     Isolators and safety cabinets are used in handling cells and microorganisms during, for example, pathogen research and regenerative medical treatment. 
     In a safety cabinet as an open system (class II cabinet for biohazard countermeasures), clean air is supplied to the work room in the apparatus from the upper blowout portion of the work room with dust, pathogens, and so on filtered with a HEPA filter or the like. Then, the air in the room where the safety cabinet is disposed is suctioned, together with the air in the work room, through the work opening portion in the front of the work room from the intake port in the front of the workbench that is the lower surface of the work room. As a result, an inlet airstream is generated in the work opening portion. In addition, when the suctioned air is exhausted to the outside of the safety cabinet, the air containing pathogens and so on is filtered with an exhaust HEPA filter or the like. The HEPA filter is an abbreviation for a high efficiency particulate air filter. The inlet airstream generated in the work opening portion prevents the pathogens and so on handled in the work room from leaking out of the safety cabinet, infecting a worker, and spreading to the environment. Patent Document 1 illustrates a safety cabinet as an example. 
     CITATION LIST 
     Patent Document 
     Patent Document 1: JP 2009-119391 A 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     Work in the safety cabinet is performed with a hand in from the work opening portion below the front surface door of the cabinet, and thus workability is satisfactory. However, depending on how the work is done or how the equipment is handled, the inside of the work room may be mixed with the general air outside the equipment or the sample handled in the equipment may leak out of the work room. 
     An object of the present invention is to suppress sample contamination by strengthening the air barrier of a work opening portion. 
     Solutions to Problems 
     An example of “safety cabinet” of the present invention for solving the above problems includes: a work room; a front surface door covering a part of a front opening portion of the work room; a work opening portion on a lower side of the front surface door allowing a worker to work with his or her hand in; and an intake port suctioning air in the work room and outside air through the work opening portion on a front surface side of a workbench in a lower portion of the work room, in which a straightening plate drawing an air flow is provided on the work room side of the front surface door and above a front portion of the work room. 
     Effects of the Invention 
     According to the present invention, it is possible to provide a safety cabinet capable of suppressing sample contamination by strengthening the air barrier of a work opening portion. 
     Tasks, configurations, and effects other than those described above are apparent from the description of the following embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external front view illustrating a safety cabinet of a first embodiment. 
         FIG. 2  is a side cross-sectional view illustrating the safety cabinet of the first embodiment. 
         FIG. 3  is a diagram illustrating the flow of air during the operation of the safety cabinet of  FIG. 2 . 
         FIG. 4  is an enlarged view illustrating a part of the safety cabinet of the first embodiment. 
         FIG. 5  is an enlarged view illustrating a part of a safety cabinet of a second embodiment. 
         FIG. 6  is an enlarged view illustrating a part of a safety cabinet of a third embodiment. 
         FIG. 7  is an enlarged view illustrating a part of a safety cabinet of a fourth embodiment. 
         FIG. 8A  is a front view of a safety cabinet of a fifth embodiment. 
         FIG. 8B  is a side cross-sectional view of the safety cabinet of the fifth embodiment. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention will be described with reference to the drawings. It should be noted that the same constituent element in the drawings for describing the embodiments is given the same name and reference numeral to the maximum extent possible with redundant description omitted. 
     First Embodiment 
       FIG. 1  illustrates a schematic front view of a safety cabinet. In addition,  FIG. 2  illustrates a side cross-sectional view of the safety cabinet in which the A-A′ cross section of  FIG. 1  is viewed from the right. 
     An opening is provided in the middle region of a housing  1  of a safety cabinet  100 , and a work room  4  is provided behind the opening. A front surface door  2  is provided on the front surface side of the work room  4  so as to block the upper portion of the opening, a work opening portion  3  is provided on the lower side of the front surface door  2 , and a worker performs work with his or her hand in the work room  4  from the work opening portion  3 . The front surface door  2  is formed of a transparent material such as glass, and the worker can visually check the work through the front surface door  2 . 
     A substantially flat workbench  5  is provided on the bottom surface of the work room  4 , and the worker performs the work on the workbench. A front intake port  7  leading downward is provided on the front side of the workbench  5  and near the work opening portion  3 . The front intake port  7  is formed of, for example, a slit extending in the left-right direction of the housing along the work opening portion  3 . Provided on the back surface side of the work room  4  is a back flow path  8  leading from the front intake port  7  to the upper portion of the housing. 
     A circulation fan filter unit (FFU)  9  is provided on the upper side of the work room  4 . The circulation FFU  9  is configured by a fan rotated by a motor and a fine particle removal filter such as a circulation HEPA filter  9 A, and clean air is blown out to the work room  4  through a punching plate  11  with fine particles removed. An exhaust fan filter unit (FFU)  10  is provided in the upper portion of the housing  1 , and some of the air is discharged to the outside of the apparatus through a filter such as an exhaust HEPA filter  10 A with the fine particles removed. 
       FIG. 3  illustrates the flow of air during the operation of the safety cabinet with arrows. Air  90  suctioned from the front intake port  7  on the front surface side of the workbench  5  is blown from the circulation FFU  9  to the work room  4  through the lower portion of the housing, the back flow path  8 , and the upper portion of the housing as indicated by reference numeral  91 . Clean air is blown to the work room  4  with fine particles removed by the circulation HEPA filter  9 A of the circulation FFU  9 . As a result, the work room  4  is maintained in a clean state. At this time, the air in the work room may leak to the outside with only the air flow to the work room  4  indicated by reference numeral  92 . Accordingly, the exhaust FFU  10  is provided and some of the air is released to the outside through the exhaust HEPA filter  10 A. As a result, the pressure of the work room decreases and an air flow  94  to be introduced from the outside to the inside through the work opening portion  3  below the front surface door  2  is generated. The cleanliness of the work room will decline if this air flow  94  flows into the work room as it is. However, by appropriately controlling the air volume of the flow  92  of the air blown from the circulation FFU  9  to the work room and the air volume of a flow  93  of the air discharged from the exhaust FFU  10  to the outside, the entire air  94  flowing in from the work opening portion  3  and most of the air  92  sent to the work room are suctioned from the front intake port  7  and the flow  92  of the air blown out to the work room  4  forms an atmospheric wall (air barrier) blocking the inflow of the air  94  from the work opening portion  3  into the work room  4 . As a result, an equilibrium state can be realized where the air from the outside does not contaminate the work room  4  and the internal pre-cleaning air does not leak to the outside. 
     The worker performs the work using the safety cabinet with his or her hand in the work room  4  through the work opening portion  3 , and thus the worker may become a source of contamination of the work room that is a clean and sterile environment. Accordingly, the air barrier near the work opening portion needs to be strengthened. In addition, work room lighting is necessary so that the work situation in the work room is checked by the worker. 
       FIG. 4  illustrates an example of the safety cabinet of a first embodiment of the present invention,  FIG. 4( a )  is a cross-sectional view of the vicinity of the front portion of the work room, and  FIG. 4( b )  is a perspective view thereof. 
     In the drawings, a straightening plate  20  is provided in the work room on the back side of the front surface door  2 . The straightening plate  20  is provided in the up-down direction, parallel to the front surface door  2 , and provided at a predetermined distance from the front surface door  2 . The straightening plate  20  is made of one plate and provided above the front portion of the work room  4  so as to connect the left and right side walls of the work room. A lighting mounting seat  23  where a linear light source is mounted is mounted on both sides of the straightening plate and both side walls of the work room. Further, a linear light source  22  such as a straight tube-type LED lighting lamp is mounted on the lighting mounting seat  23 . In other words, the linear light source  22  is mounted above the front portion of the work room  4  across the left and right side walls. 
     Although air is blown from above to the work room  4  by the circulation FFU  9 , the air flow is drawn toward the straightening plate  20  and the flow velocity increases (Coanda effect) in the presence of the straightening plate  20 . Accordingly, the air barrier on the back side of the front surface door  2  is strengthened, the inflow of outside air from the work opening portion  3  into the work room  4  can be blocked, and sample contamination in the work room can be prevented. 
     In addition, by mounting the linear light source  22  above the front portion of the work room, the work room is illuminated from the front and the worker can clearly check the work situation in the work room. Although the linear light source  22  may be a straight tube-type fluorescent lamp, an LED light source has directivity, and thus a necessary place such as the middle portion of the workbench can be brightly illuminated as indicated by the arrows in  FIG. 4( a )  using an LED lighting lamp. In addition, although the straightening plate  20  and the lighting mounting seat  23  may be separate bodies, the mounting is facilitated by integration. 
     According to the present embodiment, the straightening plate is provided on the work room side of the front surface door and above the front portion of the work room. Accordingly, the air barrier on the back side of the front surface door is strengthened, the inflow of outside air from the work opening portion into the work room can be blocked, and sample contamination in the work room can be prevented. In addition, by mounting the linear light source above the front portion of the work room, the work room is illuminated from the front and the worker can clearly check the work situation in the work room. 
     Second Embodiment 
       FIG. 5  illustrates an example of a safety cabinet according to a second embodiment of the present invention,  FIG. 5( a )  is a cross-sectional view of the vicinity of the front portion of the work room, and  FIG. 5( b )  is a perspective view thereof. 
     Although the straightening plate  20  and the linear light source  22  are provided in the second embodiment as well as the first embodiment, a plurality of the linear light sources  22  are provided in the present embodiment. The two linear light sources  22  in the drawings are mounted on the lighting mounting seat  23 . Further, the lower linear light source  22  close to the work opening portion  3  is disposed close to the front surface door  2  whereas the upper linear light source  22  far from the work opening portion  3  is away from the front surface door  2 . In other words, as illustrated in  FIG. 5( a ) , the line segment connecting the two linear light sources  22  is disposed at an angle of θ with respect to the front surface door  2 . 
     Although air is blown from above to the two linear light sources  22 , the air flow is drawn into the wall surface of the linear light source  22  as well as the straightening plate and the flow velocity increases. Then, an air flow having a horizontal component toward the work opening portion  3  is generated as indicated by the inclined arrow in the drawing. 
     It should be noted that three or more linear light sources  22  may be provided although two are provided in the drawings. In addition, although the two linear light sources in the drawings are in the same direction in terms of directivity, alternative options include focusing in one place or spreading. 
     According to the present embodiment, the effect of the first embodiment can be achieved and, further, the inflow of outside air from the work opening portion  3  to the work room  4  can be blocked and sample contamination can be prevented since the linear light source on the lower side (side close to the work opening portion) as one of the plurality of linear light sources is disposed close to the front surface door. 
     Third Embodiment 
       FIG. 6  illustrates an example of a safety cabinet according to a third embodiment of the present invention,  FIG. 6( a )  is a cross-sectional view of the vicinity of the front portion of a work room, and  FIG. 6( b )  is a perspective view thereof. 
     Although the straightening plate  20  and the plurality of linear light sources  22  are provided in the third embodiment as well as the second embodiment, the straightening plate  20  is reinforced in the present embodiment. In the drawings, an L-shaped bent portion is formed by bending the upper and lower portions of the straightening plate  20  at substantially right angles. Although the straightening plate  20  is configured by a flat plate and easy to bend in the first and second embodiments, the straightening plate can be reinforced by providing an L-shaped and substantially right-angled bent portion  24  above and below the straightening plate  20 . It should be noted that the bent portion  24  does not exceed the linear light source  22  in terms of length so as not to hinder the air flow indicated by the arrows and generated by the plurality of linear light sources  22 . 
     According to the present embodiment, the effect of the first embodiment can be achieved and, in addition, the bending of the straightening plate can be suppressed and the strength of the straightening plate can be increased since the L-shaped and substantially right-angled bent portion is provided above and below the straightening plate. 
     Fourth Embodiment 
       FIG. 7  illustrates an example of a safety cabinet according to a fourth embodiment of the present invention,  FIG. 7( a )  is a cross-sectional view of the vicinity of the front portion of a work room, and  FIG. 7( b )  is an enlarged view thereof. 
     Although the straightening plate  20  is provided with the bent portion  24  in the present embodiment as well as the third embodiment, the flow of air by the bent portion  24  of the straightening plate is improved in the present embodiment. In  FIG. 7( b ) , a slit  25  is formed in the L-shaped bent portion  24  in the lower portion of the straightening plate  20 . As illustrated in the drawing, the air in the bent portion  24  of the straightening plate  20  is capable of escaping downward through the slit  25  and an air flow having a horizontal component toward the work opening portion  3  is generated. It should be noted that a slit may be provided in the vicinity of the bent portion  24  of the straightening plate  20  as well as illustrated in the drawing. 
     According to the present embodiment, the slit is provided in the L-shaped bent portion in the lower portion of the straightening plate. Accordingly, the effect of the first embodiment can be achieved and, in addition, the bending of the straightening plate can be suppressed, the strength of the straightening plat can be increased, the inflow of outside air from the work opening portion into the work room can be further blocked, and sample contamination can be prevented. 
     Fifth Embodiment 
       FIG. 8A  illustrates a front view of a safety cabinet of a fifth embodiment of the present invention, and  FIG. 8B  illustrates a cross-sectional view of the safety cabinet as viewed from the right side. 
     In a case where a worker&#39;s head, clothes, or the like is dirty, dust may flow into the work room and contaminate the sample in the work room. The present embodiment is to allow a worker to check his or her clothes or the like in advance. 
     As illustrated in the drawings, a decorative cover  30  installed in front of a worker is made of mirror-finished stainless steel. As a result, the area around the face, clothes, and so on, where the risk of dust generation is high, can be checked before work. In addition, the feeling of oppression of the apparatus can be reduced by specular reflection. 
     In addition, the feeling of oppression of the apparatus can be reduced by a curtain plate  35  for filling the gap between the safety cabinet and an indoor ceiling surface being made of mirror-finished stainless steel. 
     REFERENCE SIGNS LIST 
     
         
           1  Housing 
           2  Front surface door 
           3  Work opening portion 
           4  Work room 
           5  Workbench 
           7  Intake port 
           8  Back flow path 
           9  Circulation fan 
           9 A Circulation HEPA filter 
           10  Exhaust fan 
           10 A Exhaust HEPA filter 
           11  Punching plate 
           20  Straightening plate 
           22  Linear light source 
           23  Lighting mounting seat 
           24  Bent portion 
           25  Slit 
           30  Decorative cover 
           35  Curtain plate 
           100  Safety cabinet