Patent Publication Number: US-2020297884-A1

Title: Disinfection apparatus

Description:
BACKGROUND 
     1. Field 
     The present disclosure relates to a disinfection apparatus for disinfecting a ceiling space. 
     2. Description of Related Art 
     Demolition and repair of a building generate a significant amount of dust, which can contain a large amount of  Aspergillus  spores. In hospitals and elderly facilities, the patients and elderly people with weakened immune systems in these facilities face a high risk of  Aspergillus  infection when inhaling the spores. For this reason, demolition methods have been contemplated that limit spreading of  Aspergillus  fungi during demolition to limit  Aspergillus  infection. See Japanese Laid-Open Patent Publication No. 2018-131878, for example. The demolition method described in this publication uses a disinfection apparatus having a sprayer with a pneumatic atomizing nozzle. The disinfection apparatus is inserted and installed into the ceiling space through an opening. The sprayer sprays mist of a chemical solution for disinfection. 
     As described in Japanese Laid-Open Patent Publication No. 2018-131878, in order to disinfect by spraying mist of the chemical solution, the mist is sprayed until the humidity in the ceiling space to be disinfected reaches the target relative humidity (for example, 80%). To prevent leakage of the sprayed mist through the opening, the opening used to insert the sprayer into the ceiling space is covered by a plastic sheet, for example. However, covering the opening takes time and trouble, hindering efficient disinfection work. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     In one general aspect, a disinfection apparatus that includes an installation member is provided. The installation member includes a sealing member configured to seal a hole located in a ceiling, a nozzle configured to be placed in a ceiling space through the hole and spray a chemical solution to disinfect the ceiling space, a mount member configured to place the nozzle above the sealing member, and a fixing member configured to maintain a state in which the sealing member seals the hole. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view showing an installation member of a disinfection apparatus of a first embodiment in a state before sealing. 
         FIG. 1B  is a perspective view showing the installation member of the first embodiment. 
         FIG. 2  is a block diagram showing the disinfection apparatus of the first embodiment. 
         FIG. 3A  is a perspective view showing an installation member of a disinfection apparatus of a second embodiment in a state before sealing. 
         FIG. 3B  is a perspective view showing the installation member of the second embodiment in a state after sealing in a ceiling space. 
         FIG. 4A  is a perspective view showing an installation member of a disinfection apparatus of a third embodiment in a state before sealing. 
         FIG. 4B  is a front view showing the installation member of the disinfection apparatus of the third embodiment in a state after sealing. 
         FIG. 4C  is an enlarged side view showing the main part of the installation member of the disinfection apparatus of the third embodiment in a state after sealing. 
         FIG. 5A  is a partially exploded perspective view showing an installation member of a disinfection apparatus of a fourth embodiment in a state before sealing. 
         FIG. 5B  is a front view showing the installation member of the disinfection apparatus of the fourth embodiment in a state after sealing. 
         FIG. 5C  is a front cross-sectional view showing the main part of the installation member of the disinfection apparatus of the fourth embodiment in a state after sealing. 
         FIG. 5D  is an enlarged side cross-sectional view showing the main part of the installation member of the disinfection apparatus of the fourth embodiment in a state after sealing. 
         FIG. 6A  is a partially exploded perspective view showing an installation member of a disinfection apparatus of a fifth embodiment. 
         FIG. 6B  is a front view showing the installation member of the disinfection apparatus of the fifth embodiment in a state after sealing. 
         FIG. 6C  is an enlarged side cross-sectional view showing the main part of the installation member of the disinfection apparatus of the fifth embodiment in a state after sealing. 
     
    
    
     Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION 
     This description provides a comprehensive understanding of the methods, apparatuses, and/or systems described. Modifications and equivalents of the methods, apparatuses, and/or systems described are apparent to one of ordinary skill in the art. Sequences of operations are exemplary, and may be changed as apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Descriptions of functions and constructions that are well known to one of ordinary skill in the art may be omitted. 
     Exemplary embodiments may have different forms, and are not limited to the examples described. However, the examples described are thorough and complete, and convey the full scope of the disclosure to one of ordinary skill in the art. 
     First Embodiment 
     A disinfection apparatus according to a first embodiment will now be described with reference to  FIGS. 1A, 1B, and 2 . The present embodiment disinfects a ceiling space by spraying a chemical solution having a disinfection effect, which is a solution of active ingredients, in the ceiling space. 
       FIGS. 1A and 1B  show an installation member  10  of a disinfection apparatus. 
       FIG. 2  shows a disinfection apparatus  20  including a plurality of spray devices  16 . Each spray device  16  is supported by the corresponding installation member  10  and placed in a ceiling space, that is, a space above a ceiling. The installation member  10  and the spray device  16  will be described in detail below. 
     The disinfection apparatus  20  includes a compressor  21 , an air branch  25 , a chemical solution tank  26 , flowmeters  27 , a control unit  28 , and a control panel  29 . The compressor  21 , which is movable, compresses air and supplies the compressed air to the air branch  25 . In the present embodiment, the air branch  25 , the chemical solution tank  26 , the flowmeters  27 , the control unit  28 , and the control panel  29  are mounted on a movable cart. 
     The air branch  25  divides and supplies compressed air to the spray devices  16  via air hoses  17 . A pressure gauge (not shown) is provided in the air branch  25  to measure the pressure of the compressed air supplied from the compressor  21 . 
     The chemical solution tank  26  stores a chemical solution for disinfection and supplies the chemical solution to each spray device  16 . The present embodiment uses a chemical solution produced by diluting a 6% sodium hypochlorite solution, which is used as liquid concentrate, to 0.3% to 0.5%. The flowmeters  27  are placed at the discharge port of the chemical solution tank  26 . Each flowmeter  27  measures the flow rate of the chemical solution supplied to the corresponding spray device  16  via a chemical solution tube  18 . 
     The control unit  28  controls the supply valve (not shown) of the air branch  25  and the supply valve (not shown) of the chemical solution tank to control the supply of the compressed air and the chemical solution to the spray devices  16 . The control unit  28  performs various controls in response to instructions received through the control panel  29 . 
     The control panel  29  includes a start button for starting spraying and a timer setting button. In addition, the control panel  29  displays the set time of spraying, the elapsed time from the start of spraying, the integrated flow rate of the chemical solution supplied to each spray device  16 , and the pressure of compressed air supplied to the air branch  25 , for example. 
     As shown in  FIG. 1A , the installation member  10  includes an extendable support bar  11 , which serves as a support. A base  11   a  is provided at the lower end of the support bar  11  to allow the support bar  11  to stand on the floor. The upper surface of the support bar  11  is fixed to a disk-shaped sealing member  12 . In the present embodiment, the center of the sealing member  12  is aligned with the central axis of the support bar  11 . In order to seal a circular hole h 1  in a ceiling panel C 1 , the sealing member  12  is larger than this hole h 1 . The hole h 1  is sized to allow the spray device  16  to move through the hole h 1 . 
     A vessel  13 , which serves as a container, is fixed to the center of the upper surface of the sealing member  12 . The vessel  13  is cylindrical and opens upward. The vessel  13  is smaller than the hole h 1  in circumference. Further, a drain  14  extends through the vessel  13  and the sealing member  12 . The drain  14  includes a drain cock (not shown) at the lower end. 
     A mount plate  15  extends upright from the sealing member  12 . The mount plate  15  of the present embodiment is extendable and retractable according to the height of the ceiling space, and has a length sufficient to place the spray device  16  above any obstacle, such as piping, in the ceiling space (e.g., 80 to 100 cm). 
     The upper end section of the mount plate  15  extends in the horizontal direction, and the spray device  16  is attached to this upper end section. The spray device  16  includes a tank, which temporarily stores the chemical solution, and a plurality of nozzles  16 N, which sprays mist. Each nozzle  16 N of the present embodiment is a pneumatic atomizing siphon spray nozzle, which sprays a chemical solution using the pressure of compressed air. Specifically, Quick Fogger (trade name) manufactured by SPRAYING SYSTEMS CO., JAPAN is used as the spray device  16 . With this spray device  16 , the amount of liquid sprayed from the nozzle  16 N per unit time is controllable by changing the pressure of the compressed air. In the present embodiment, the nozzles  16 N may be oriented in four directions. Thus, the nozzles may be orientated in selected two directions (e.g., two opposite directions) of the four directions according to an obstacle in the ceiling space. The arranged nozzles spray mist having a particle diameter of 9 to 11 μm. 
     Each spray device  16  is connected to an air hose  17  and a chemical solution tube  18 . The air hose  17  and the chemical solution tube  18  extend through couplers (not shown), which extend through the sealing member  12 , to the lower side of the sealing member  12 . The air hose  17  is connected to the air branch  25 , and the chemical solution tube  18  is connected to the chemical solution tank  26 . 
     [Disinfection Method] 
     A method for disinfection using the disinfection apparatus is now described. 
     First, the installation position of the spray device  16  is determined according to the shape and area of the ceiling space to be disinfected. A circular hole h 1  is formed in the ceiling panel C 1  corresponding to the installation position. 
     As shown in  FIG. 1A , the cart and the compressor  21  are placed near the hole h 1 , and the support bar  11  of the installation member  10  is placed to stand in a retracted state on the floor directly below the hole h 1 . The length of the mount plate  15  is adjusted in accordance with the height of the ceiling space in which the spray device  16  is installed. 
     Then, the support bar  11  is extended, moving the spray device  16  through the hole h 1  and inserting the vessel  13  into the hole h 1 . This brings the sealing member  12  into contact with the lower surface of the ceiling. As shown in  FIG. 1B , the sealing member  12  thus seals the hole h 1 . The support bar  11  is fixed to maintain the length in this state. 
     All spray devices  16  are installed in the respective target positions by the installation method described above. 
     Compressed air and the chemical solution are supplied to the spray devices  16  via the air hoses  17  and the chemical solution tubes  18  by activating the compressor  21  and operating the control panel  29 . The nozzles  16 N of each spray device  16  spray the chemical solution into the ceiling space to perform disinfection. The vessel  13  receives any chemical solution dripped from the spray device  16 . 
     The control unit  28  continues the spraying until the spraying end time, at which the relative humidity in the ceiling space becomes greater than or equal to the target relative humidity (e.g., 80%). The target relative humidity is a humidity capable of killing  Aspergillus  fungi. The spraying end time is determined according to the area (volume) of the ceiling space. 
     When the spraying end time is reached, the control unit  28  of the disinfection apparatus  20  stops the supply of compressed air and the chemical solution. The disinfection apparatus  20  is left to stand for a predetermined time (e.g., several minutes), and then the drain cock is opened to discharge the chemical solution stored in the vessel  13  through the drain  14 . The support bar  11  is retracted to lower the sealing member  12 , moving the spray device  16  out of the ceiling space. 
     The present embodiment has the following advantages. 
     (1-1) In the present embodiment, each installation member  10  of the disinfection apparatus  20  includes the sealing member  12 , to which the spray device  16  is coupled, and the extendable support bar  11 , which is coupled to the sealing member  12  at the upper end. The support bar  11  is extended to insert the spray device  16  into the hole h 1  of the ceiling panel C 1  and to press the sealing member  12  against the ceiling to seal the hole h 1 . The support bar  11  stands upright in this position, keeping the hole h 1  sealed. The installation of the spray device  16  in the ceiling space and the sealing of the hole h 1  are achieved in a single series of actions, increasing the efficiency of the disinfection work. 
     (1-2) The present embodiment includes the vessel  13  fixed to the upper surface of the sealing member  12 . The vessel  13  stores the chemical solution dripped from the nozzles  16 N of the spray device  16 . This reduces the likelihood that the chemical solution drips from the ceiling when the sealing member  12  is removed, for example. 
     (1-3) The disinfection apparatus  20  of the present embodiment includes a plurality of spray devices  16 . Each spray device  16  receives compressed air from the air branch  25  and the chemical solution from the chemical solution tank  26 . This allows simultaneous spraying of mist from the plurality of spray devices  16 . 
     (1-4) The present embodiment includes the mount plate  15  coupled to the sealing member  12  to support the spray device  16 . The mount plate  15  is long enough to place the spray device  16  above an obstacle, such as piping, in the ceiling space. Consequently, the mist from the nozzles  16 N is sprayed efficiently without being interfered by the obstacle. 
     Second Embodiment 
     A disinfection apparatus according to a second embodiment will now be described with reference to  FIGS. 3A and 3B . The present embodiment disinfects a ceiling space above a system ceiling. The sealing member of the second embodiment is different from that of the first embodiment. In the following description, same reference numerals are given to those components that are the same as the corresponding components of the above embodiment. Such components will not be described in detail. 
     In the present embodiment, as shown in  FIG. 3A , a system ceiling is formed by arranging ceiling joists, which may be T-bars, in a grid and covering each of the spaces surrounded by the grid ceiling joists with a ceiling panel C 2 . The grid of the ceiling joists may include 450 mm squares, 600 mm squares, or 600 mm×1200 mm rectangles, for examples. 
     The installation member  30  of the present embodiment includes an extendable support bar  11 , a sealing member  32 , a mount plate  15 , and a spray device  16 . The sealing member  32  is a tetragonal panel having substantially the same size as the ceiling panel C 2 . The sealing member  32  seals a hole surrounded by the grid ceiling joists. A vessel  33 , having the shape of a tetragonal frame, is arranged on the sealing member  32 . The vessel  33  is sized to be inserted into the hole surrounded by the grid ceiling joists. 
     This embodiment uses the same disinfection steps as the embodiment described above. The ceiling panel C 2  corresponding to the position in which the spray device  16  is installed is removed to form a hole h 2  connecting to the ceiling space. 
     Then, the support bar  11  of the installation member  30  is placed upright on the floor directly below the hole h 2 . The support bar  11  is extended to elevate the spray device  16  and the sealing member  32 . As shown in  FIG. 3B , this moves the spray device  16  through the hole h 2  and brings the sealing member  32  into contact with the lower surface of the ceiling joists, thereby sealing the hole h 2 . Then, the compressor  21  is activated to spray the chemical solution from the nozzles  16 N of the spray device  16  to perform disinfection. 
     In addition to Advantages (1-1) to (1-4) described above, the present embodiment has the following advantage. 
     (2-1) In the present embodiment, the installation member  30  of the disinfection apparatus  20  includes the sealing member  32  having a shape corresponding to the grid of the grid ceiling. This achieves efficient disinfection of the ceiling space above the grid ceiling without forming a hole in the ceiling. 
     Third Embodiment 
     A disinfection apparatus according to a third embodiment will now be described with reference to  FIGS. 4A to 4C . The first and second embodiments seal the holes with the sealing members supported by the extendable support bars  11 . The present embodiment inserts a spray device into a ceiling space through an access opening formed in the ceiling. The installation member is hooked to the frame surrounding the access opening to seal the access opening. 
     As shown in  FIG. 4A , an access opening frame F 3  having the shape of a tetragonal frame is arranged in the ceiling space around the periphery of the access opening. In addition, a plurality of ceiling joists Mb 1  is arranged on the ceiling panel C 3  in the ceiling space. 
     An installation member  40  includes a plurality of slide hooks  41 , which serves as fixing members (engagement portions), a sealing member  42 , and an insertion portion  43 . The sealing member  42  is large enough to cover the access opening. The insertion portion  43  is arranged on the central section of the sealing member  42 . The insertion portion  43  has the shape of a tetragonal frame sized to be inserted into the access opening. The insertion portion  43  has four through holes, each receiving a slide hook  41 , which can slide in the horizontal direction in the through hole. In the present embodiment, the four slide hooks  41  include two pairs of slide hooks  41 . The two slide hooks  41  in each pair are spaced apart from each other along one straight line. 
     As shown in  FIGS. 4A and 4B , a mount member  44   a  is located in the region surrounded by the insertion portion  43  on the upper surface of the sealing member  42 . The insertion portion  43  functions as a container for receiving dripped chemical solution. The mount member  44   a  includes a plurality of coupling holes arranged in the lateral direction. The lower end of a stay  44   b  and the lower end of a mount plate  45  are fixed to the mount member  44   a  by fasteners, such as bolts and nuts. The upper end of the stay  44   b  is coupled to the central section of the mount plate  45  to support the mount plate  45 . The mount plate  45  is the same as the mount plate  15  of the first embodiment. 
     The spray device  16  is attached to the upper end of the mount plate  45 . The air hose  17  and the chemical solution tube  18  connected to the spray device  16  extend through the sealing member  42 . 
     As shown in  FIG. 4C , each slide hook  41  is substantially an inverted L-shaped plate including a projection  41   a  at the upper end. The projection  41   a  extends toward the outside of the installation member  40 . The lower surface of the projection  41   a  is inclined so as to be higher toward the outside of the installation member  40 . The lower surface of the projection  41   a  is high enough to be hooked onto the upper end of the access opening frame F 3 . 
     The lower end of the slide hook  41  extends through the sealing member  42  and protrudes from the lower surface of the sealing member  42 . The lower end is slidable along the insertion portion  43 . 
     In the present embodiment, to perform disinfection, the access door covering the access opening is removed, and the cart and the compressor  21  are placed near the access opening. 
     Coupling holes are selected according to the installation position of the spray device  16 , and the mount plate  45  and the stay  44   b  are engaged with and fixed to these coupling holes with fasteners. The mount plate  45  and the stay  44   b  are thus fixed. 
     As shown in  FIG. 4A , the installation member  40  is placed directly below the access opening. 
     Then, as shown in  FIG. 4B , the installation member  40  is lifted to place the spray device  16  in the ceiling space through the access opening, and the sealing member  42  is brought into contact with the lower surface of the ceiling panel C 3 . 
     As shown in  FIG. 4C , with the sealing member  42  in contact with the lower surface of the ceiling panel C 3 , the lower ends of the slide hooks  41  are moved so that the sealing member  42  engages with the upper end of the access opening frame F 3 . Thus, the spray device  16  is installed in the ceiling space, and the installation member  40  is fixed to the access opening frame F 3  with the sealing member  42  sealing the access opening. The compressor  21  is then activated to spray the chemical solution from the nozzles  16 N of the spray device  16  to perform disinfection. The insertion portion  43  receives any chemical solution dripped from the spray device  16 . 
     In addition to advantages equivalent to (1-3) and (1-4), the present embodiment has the following advantage. 
     (3-1) The installation member  40  of the present embodiment includes the sealing member  42 , which is coupled to the spray device  16 , and a plurality of slide hooks  41 , which is arranged in the insertion portion  43  of the sealing member  42  in a slidable manner. This allows the slide hooks  41  to engage with the upper surface of the access opening frame F 3 , thereby installing the spray device  16  in the ceiling space and maintaining a state in which the sealing member  42  seals the access opening. 
     (3-2) In the present embodiment, each slide hook  41  includes an upper projection  41   a , and the lower surface of the projection  41   a  is inclined. This allows the slide hook  41  to be moved into engagement with the access opening frame F 3 . 
     (3-3) The present embodiment includes the mount member  44   a , which has a plurality of coupling holes and is located on the sealing member  42  of the installation member  40 . The mount member  44   a  is coupled with the mount plate  45 , to which the spray device  16  is attached, and the stay  44   b , which is connected to the mount plate  45 . Thus, the position where the mount plate  45  is coupled to a coupling hole is adjustable. 
     (3-4) The present embodiment includes the insertion portion  43  fixed to the upper surface of the sealing member  42 . Any chemical solution dripped from the nozzles  16 N is stored inside this insertion portion  43 , reducing the likelihood that the chemical solution drips from the ceiling when the sealing member  42  is removed, for example. 
     Fourth Embodiment 
     A disinfection apparatus according to a fourth embodiment will now be described with reference to  FIGS. 5A to 5D . In the third embodiment, the spray device  16  is attached to the upper end of the mount plate  45  of the installation member  40 , and the installation member  40  is fixed with the slide hooks  41 . In the present embodiment, only the nozzles of the spray device are attached to the mount plate, and disinfection is performed without removing the access door. 
       FIG. 5A  is a partially exploded perspective view of an installation member  50  of the present embodiment.  FIG. 5B  is a schematic front view of the installation member  50 .  FIG. 5C  is an enlarged cross-sectional front view partially showing the main part of the installation member  50 .  FIG. 5D  is an enlarged cross-sectional side view partially showing the main part of the installation member  50 . 
     As shown in  FIGS. 5A and 5B , an access opening frame F 4 , which has the shape of a tetragonal frame, is placed in a ceiling space around the periphery of an access opening formed in a ceiling. An access door D 4  is attached using an engagement member so as to open and close the access opening. 
     The installation member  50  of the present embodiment includes a plurality of fixing members  51 , a sealing member  52 , and an insertion portion  53 . The fixing members  51  will be described in detail below. 
     As shown in  FIG. 5C , the sealing member  52  is sized to cover the region of the access opening when the access door D 4  is opened. On the central section of the sealing member  52 , the planar insertion portion  53  extends upright to form a rectangular frame. The insertion portion  53  functions as a container for receiving dripped chemical solution. 
     As shown in  FIG. 5A , a fixing member  51  is placed at each corner of the insertion portion  53 . Further, as shown in  FIGS. 5A and 5B , a spray tank  56 T is placed under the sealing member  52 . The spray tank  56 T is a part of the spray device separated from the nozzles  56 N. 
     As shown in  FIGS. 5B and 5C , support bases  54   a  and  54   b  are arranged to intersect with each other in the region of the upper surface of the sealing member  52  surrounded by the insertion portion  53 . The long dashed short dashed lines in  FIG. 5A  indicate the positions along the outer shape of the insertion portion  53  at which the support bases  54   a  and  54   b  engage. The two ends of each of the support bases  54   a  and  54   b  are bent downward and fitted to the outer side of the insertion portion  53 . The support bases  54   a  and  54   b  have a plurality of engagement holes. The arrangement of the support bases  54   a  and  54   b  in the installation member  40  is changeable by adjusting positions of the engagement holes of the support bases  54   a  and  54   b  when the support bases  54   a  and  54   b  are brought into engagement. An extendable mount plate  55  extends upright from the support base  54   a . A fixing clip  55   a  is fixed to the lower end of the mount plate  55 . In the present embodiment, the fixing clip  55   a  is attached to the support base  54   a . The mount plate  55  is the same as the mount plate  15  of the first embodiment. 
     A plurality of nozzles  56 N is attached to the upper end of the mount plate  55  in a rotational manner. The plurality of nozzles  56 N sprays mist in opposite directions along a straight line. The nozzles  56 N are a part of the spray device  16  separated from the spray tank  56 T. 
     As shown in  FIG. 5B , an air hose  17   a  and a chemical solution tube  18   a  are connected to the nozzles  56 N. The air hose  17   a  is connected to the compressor  21  via a coupler  17   c , which is provided in the sealing member  52 , and an air hose  17   b . The chemical solution tube  18   a  is connected to the spray tank  56 T via a coupler  18   c  provided in the sealing member  52 . The spray tank  56 T is connected to the chemical solution tank  26  via a chemical solution tube  18   b.    
     Referring to  FIG. 5D , the fixing members  51  are now described in detail. 
     Each fixing member  51  includes a hook plate  51   a  at the upper end, a handle  51   c  at the lower end, and a shaft  51   b  fixed to the hook plate  51   a  and an end of the handle  51   c . The hook plate  51   a  is an engagement portion having a length extending to the access opening frame F 4 . The shaft  51   b  extends through the sealing member  52  at the inner side of the corresponding corner of the insertion portion  53 . The shaft  51   b  has a length greater than the height of the access opening frame F 4 . A spring  51   s  is arranged along the section of the shaft  51   b  between the lower surface of the sealing member  52  and the upper surface of the handle  51   c.    
     To perform disinfection, the cart and the compressor  21  are set, and the access door covering the access opening is opened. Then, as shown in  FIG. 5A , the support bases  54   a  and  54   b  are engaged with the upper end of the insertion portion  53 , and the fixing clip  55   a  of the mount plate  55  is attached to the support base  54   a  to set the nozzles  56 N on the installation member  50 . According to the installation position of the nozzles  56 N, the support bases  54   a  and  54   b  may be moved along the upper end of the insertion portion  53 . 
     Then, the installation member  50  is lifted so that the nozzles  56 N are placed in the ceiling space through the access opening, inserting the insertion portion  53  of the installation member  50  into the access opening. As shown in  FIG. 5C , the installation member  50  is further lifted to bring the sealing member  52  into contact with the lower surface of the ceiling panel C 4 . 
     With the sealing member  52  in contact with the lower surface of the ceiling panel C 4 , the handle  51   c  of each fixing member  51 , which is indicated by a solid line in  FIG. 5D , is held to press the fixing member  51  upward, compressing the spring  51   s . As indicated by the long dashed double-short dashed lines in  FIG. 5D , the hook plate  51   a  is rotated by rotating the handle  51   c  and engaged with the upper end of the access opening frame F 4 . The restoring force of the spring  51   s  draws the hook plate  51   a  downward, thereby fixing the hook plate  51   a  to the access opening frame F 4 . As a result, the nozzles  56 N are installed in the ceiling space, and the installation member  50  is fixed to the access opening frame F 4  with the sealing member  52  sealing the access opening. 
     Further, as shown in  FIG. 5C , a sheet member C 0  or a rubber member covers a section of the access door D 4  and a section of the ceiling near the engagement member of the access door D 4 . Then, the compressor  21  is activated to spray the chemical solution from the nozzles  56 N to perform disinfection. Any chemical solution dripped from the nozzles  56 N is stored inside the insertion portion  53 . 
     In addition to advantages equivalent to (1-3), (1-4), and (3-4), the present embodiment has the following advantage. 
     (4-1) In the present embodiment, the installation member  50  includes the sealing member  52 , which is coupled with the nozzles  56 N for spraying mist, and the fixing members  51  attached to the sealing member  52 . Each fixing member  51  includes a hook plate  51   a  at the upper end of the shaft  51   b . The fixing member  51  is pressed upward and rotated to engage the hook plate  51   a  with the upper surface of the access opening frame F 4 . This installs the nozzles  56 N in the ceiling space and maintains the state in which the sealing member  52  seals the access opening. 
     (4-2) In the present embodiment, the installation member  50  is fixed to the access opening frame F 4  without removing the access door D 4 . The sealing member  52  thus seals the access opening with the access door D 4  attached. 
     (4-3) In the present embodiment, the nozzles  56 N, which are separated from the spray tank  56 T, are attached to the mount plate  55  extending upright from the sealing member  52  of the installation member  50 . As such, even when the ceiling space has a narrow clearance due to an obstacle such as piping, the nozzles  56 N can be placed in the narrow clearance to spray mist. 
     Fifth Embodiment 
     A disinfection apparatus according to a fifth embodiment will now be described with reference to  FIGS. 2 and 6A to 6C . In the fourth embodiment described above, the mount plate to which only the nozzles of the spray device are attached is coupled to the sealing member. The present embodiment includes a nozzle installation member including a mount plate to which only the nozzles of the spray device are attached. The nozzle installation member is coupled separately from the sealing member. In a similar manner as the fourth embodiment, the present embodiment performs disinfection without removing the access door. 
       FIG. 6A  is an exploded perspective view in which an installation member  60  of the present embodiment is partially exploded.  FIG. 6B  is a schematic front view showing the installation member  60  in a state after sealing.  FIG. 6C  is an enlarged cross-sectional side view partially showing the main part of the installation member  60 . 
     The installation member  60  of the present embodiment includes a nozzle installation member  60   a  and a seal installation member  60   b . The nozzle installation member  60   a  and the seal installation member  60   b  are separate members, which are attached to an access opening frame F 4  separately. 
     The nozzle installation member  60   a  includes a cross-shaped support base  64  made of a magnetic material. The four ends of the support base  64  are bent downward and fit to the outer side of the access opening frame F 4 . A spray tank  66 T is fixed on the support base  64 . The air hose and the chemical solution tube connected to the spray tank  66 T extend through the sealing member  62  of the seal installation member  60   b  via couplers  17   c  and  18   c  and are connected to the air branch and the chemical solution tank. 
     Further, a mount bar  65  is fixed to the support base  64 . A neodymium magnet is provided at the bottom of the mount bar  65 . The magnetic force allows the mount bar  65  to stand stably at a desired position on the support base  64 . 
     As shown in  FIGS. 6A and 6B , multiple (two) nozzles  66 N are rotationally attached to the upper end section of the mount bar  65  at different positions in the up-down direction. The nozzles  66 N are a part of the spray device  16  separated from the spray tank  66 T. The nozzles  66 N are rotated to spray mist in desired directions. The nozzles  66 N are supported by the support base  64  and the mount bar  65 . Each nozzle  66 N is connected to an air hose  17   a  and a chemical solution tube  18   a  and receives compressed air and the chemical solution from the spray tank  66 T. In the present embodiment, the height H 1  of each nozzle  66 N (the upper nozzle  66 N in this example) from the liquid surface in the spray tank  66 T is set to be less than or equal to a predetermined height that does not affect the amount of sprayed mist (e.g., 30 cm). 
     A hygrometer  68  is located above the nozzles. The hygrometer  68  is attached to the mount bar  65  via a rotational mount member. 
     The hygrometer  68  of the present embodiment is connected to the control unit  28  shown in  FIG. 2  and sends the measured humidity (the measurement value) to the control unit  28 . Further, in the present embodiment, the control panel  29  includes an automatic stop button for stopping the spraying when the humidity reaches the target relative humidity. When the automatic stop button is selected, the control unit  28  periodically determines whether the humidity obtained from the hygrometer  68  has reached the target relative humidity. When the humidity reaches the target relative humidity, the control unit  28  stops the spraying from the nozzles  66 N. 
     The seal installation member  60   b  includes a plurality of fixing members  61 , a sealing member  62 , and a plurality of tubular members  63 . 
     The sealing member  62  is a rectangular panel and large enough to cover the access opening. The sealing member  62  includes an opening  69  in one edge section. The opening  69  is configured to receive the access door D 4 . The four tubular members  63  are fixed to the upper surface of the sealing member  62 . The tubular members  63  extend upright from the sealing member  62  at positions near the corners so as to be placed within the access opening. The height of the upper surfaces of the tubular members  63  is slightly less than the height of the access opening frame F 4 . 
     As shown in  FIG. 6C , in a similar manner as the fixing members  51  of the fourth embodiment, each fixing member  61  includes a hook plate  61   a , a handle  61   c , and a shaft  61   b . The hook plate  61   a  is an engagement portion, which is located at the upper end of the shaft  61   b  and has a length extending to the access opening frame F 4 . When the hook plate  61   a  is not in engagement with the access opening frame F 4 , the hook plate  61   a  engages with the upper surface of the tubular member  63 . The handle  61   c  is located at the lower end of the shaft  61   b . The shaft  61   b  extends through the sealing member  62  and the tubular member  63  and has a length greater than the height of the access opening frame F 4 . A spring  61   s  is arranged along the section of the shaft  61   b  between the lower surface of the sealing member  62  and the upper surface of the handle  61   c.    
     In the present embodiment, to perform disinfection, the cart and the compressor  21  are set, and the access door is opened. As shown in  FIG. 6A , the support base  64 , to which the spray tank  66 T is fixed in advance, is tilted and inserted through the access opening, and the ends of the support base  64  are hooked onto the upper end of the access opening frame F 4 . The mount bar  65 , to which the nozzle  66 N and the hygrometer  68  are attached, is fixed to the support base  64  with its position adjusted to avoid obstacles in the ceiling space. The length of the mount bar  65  is adjusted to complete the installation of the nozzle installation member  60   a  in the ceiling space. 
     Then, the coupler  17   c  of the air tube and the coupler  18   c  of the chemical solution tube, which are connected to the spray tank  66 T, are connected to the corresponding couplers  17   c  and  18   c  of the sealing member  62 . The seal installation member  60   b  is lifted such that the access door D 4  is inserted into the opening  69  of the sealing member  62 , and the sealing member  62  is brought into contact with the lower surface of the ceiling panel C 4 . 
     In this state, each handle  61   c  is held to press the fixing member  61  upward while compressing the spring  61   s  so that the hook plate  61   a  is located above the upper surface of the access opening frame F 4 . As indicated by the long dashed double-short dashed lines in  FIG. 6C , the hook plate  61   a  is rotated by rotating the handle  61   c  and engaged with the upper end of the access opening frame F 4 . Thus, the seal installation member  60   b  is fixed, and the sealing member  62  seals the access opening under the nozzle installation member  60   a . A sheet member C 0  (or a rubber member) fixed in advance around the opening  69  closes the gap between the opening  69  of the sealing member  62  and the access door D 4 . Then, the compressor  21  is activated to spray the chemical solution from the nozzles  66 N to perform disinfection. 
     In addition to advantages equivalent to (1-3), (4-1), and (4-2), the present embodiment has the following advantage. 
     (5-1) The installation member  60  of the present embodiment includes the nozzle installation member  60   a , which includes the support base  64  to which the nozzles  66 N are fixed, and the seal installation member  60   b , which includes the sealing member  62  and is separated from the nozzle installation member  60   a . This allows the nozzles  66 N to be set on the access opening frame F 4  separately from the sealing member  62  before the installation of the sealing member  62 . Thus, the position of the nozzles  66 N is adjustable separately from the sealing member  62 . 
     (5-2) The nozzles  66 N of the present embodiment are arranged in two upper and lower tiers, and an air hose  17   a  and a chemical solution tube  18   a  are connected to each nozzle  66 N. The air hose  17   a  and the chemical solution tube  18   a  are therefore unlikely to hinder the adjustment of the orientation of the nozzle  66 N, allowing the compressed air and the chemical solution to be smoothly supplied to each nozzle  66 N. 
     (5-3) The height H 1  of each nozzle  66 N of the present embodiment from the liquid surface in the spray tank  66 T is set to be less than or equal to a predetermined height that does not affect the amount of sprayed mist. The amount of sprayed mist decreases as the height of the nozzle  66 N from the liquid surface in the spray tank  66 T increases. Thus, setting the height of the nozzle  66 N to be less than or equal to the predetermined height limits decrease in the amount of sprayed mist. 
     (5-4) In the present embodiment, the shaft  61   b  of each fixing member  61  extends through the tubular member  63  projecting from the sealing member  62 , and the upper surface of the tubular member  63  supports the hook plate  61   a . Thus, the fixing of the sealing member  62  is achieved by pressing and moving each fixing member  61  upward only by the distance between the tubular member  63  and the access opening frame F 4  and rotating the fixing member  61 . 
     (5-5) The present embodiment includes the hygrometer  68  located above the nozzles  66 N. This allows the hygrometer  68  to be set in the ceiling space simultaneously with the installation of the nozzles  66 N. 
     (5-6) In the present embodiment, when the automatic stop button is selected, the control unit  28  stops the spraying from the nozzles  66 N when the humidity measured by the hygrometer  68  reaches the target relative humidity. The present embodiment stops the spraying when the hygrometer detects that the humidity necessary for disinfection is achieved, allowing for the efficient spraying of the chemical solution. 
     The above-described embodiments may be modified as follows. The above-described embodiments and the following modifications can be combined as long as the combined modifications remain technically consistent with each other. 
     In the first to fourth embodiments, the spray device  16  or the nozzles  56 N are attached to the mount plate that is long enough to place the spray device  16  above an obstacle, such as piping, in the ceiling space. However, the spray device  16  or the nozzles  56 N may be supported by the installation member using a shorter mount plate. Further, the spray device  16  or the nozzles  56 N may be supported by a mount plate coupled to the sealing member via a mechanism that allows switching between different types of mount plates. 
     In the third to fifth embodiments, the spray device  16  or the nozzles  56 N,  66 N are placed in the ceiling space through the access opening, and the installation members  40 ,  50  and  60  engage with the access opening frames F 3  and F 4  to seal the access openings with the sealing members  42 ,  52  and  62 . The members that are brought into engagement to maintain the sealing member in a sealing state is not limited to the access opening frames F 3  and F 4  and may be the access door or other ceiling access opening components, which form the ceiling access opening, or ceiling components, which form the ceiling. The ceiling components include the ceiling panel C 1  with the hole h 1  of the first embodiment and the grid ceiling of the second embodiment. For the grid ceiling, the grid of the grid ceiling may be brought into engagement to maintain the sealing member in a sealing state. 
     The third embodiment uses the slide hooks  41  to fix the installation member  40  to the access opening frame F 3 . In the fourth and fifth embodiments, the installation members  50  and  60  are fixed to the access opening frames F 4  using the fixing members  51  and  61 . The structure for fixing the installation member to a ceiling access opening component or a ceiling component is not limited to the fixing members  51  or  61 . For example, the installation members ( 40 ,  50  and  60 ) of the third to fifth embodiments may be placed on a ceiling panel with a hole or on the grid ceiling joists. Further, the installation member may be fixed to the ceiling joists Mb 1  in the ceiling space. 
     In the third to fifth embodiments, the slide hooks  41  and the fixing members  51  and  61  engage with the access opening frames F 3  and F 4  to fix the sealing members  42 ,  52  and  62  so as to seal the access opening. However, instead of the slide hooks  41  and the fixing members  51  and  61 , the support bar  11  of the first and second embodiments may be used to maintain a state in which the sealing member seals the access opening. Further, the support of the installation member is not limited to the support bar  11 , and may be a jack, for example. 
     The third embodiment removes the access door to set the installation member  40 , whereas the fourth and fifth embodiments set the installation members  50  and  60  without removing the access door D 4 . In the third embodiment, the sealing member may be set without removing the access door. In the fourth and fifth embodiments, the access door D 4  may be removed to set the sealing member. 
     The first to third embodiments set the spray devices  16  in the ceiling space, whereas the fourth and fifth embodiments set the nozzles  56 N and  66 N, which are separated from the spray tanks  56 T and  66 T, in the ceiling space. As long as the chemical solution is sprayed in the ceiling space, the tanks may be separated from the nozzles also in the first to third embodiments. 
     The fourth embodiment sets the nozzles  56 N above the sealing member  52  and sets the spray tank  56 T under the sealing member  52 . However, as with the fifth embodiment, the fourth embodiment may have a configuration that limits decrease in the amount of sprayed mist by setting the height of the nozzles  56 N from the liquid surface in the spray tank  56 T to be less than or equal to a predetermined height that does not affect the amount of sprayed mist. 
     The fifth embodiment has a plurality of tubular members  63  extending upright from the upper surface of the sealing member  62 . In addition, a container for receiving dripped chemical solution may be arranged on the center of the upper surface of the sealing member  62 . In this case, a container with a height lower than the access opening frame F 4  may be used to avoid contact with the support base  64  attached to the access opening frame F 4 , or a plurality of containers may be arranged avoiding the support base  64 . 
     The installation member  60  of the fifth embodiment includes the hygrometer  68  located above the nozzles  66 N to measure the humidity in the ceiling space. This hygrometer may be arranged not only above the nozzles  66 N but also on other portion (for example, the upper surface of the sealing member) or may be provided separately from the installation member. Further, the first to fourth embodiments may include a hygrometer. 
     In the fifth embodiment, the control unit  28  stops the spraying when the humidity measured by the hygrometer reaches the target relative humidity. The present disclosure is not limited to this, and the control unit  28  may obtain the humidity from the hygrometer at the spraying end time and, when the humidity in the ceiling space is less than the target relative humidity, may spray additional chemical solution until the target relative humidity is achieved. 
     Various changes in form and details may be made to the examples above without departing from the spirit and scope of the claims and their equivalents. The examples are for the sake of description only, and not for purposes of limitation. Descriptions of features in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if sequences are performed in a different order, and/or if components in a described system, architecture, device, or circuitry are combined differently, and/or replaced or supplemented by other components or their equivalents. The scope of the disclosure is not defined by the detailed description, but by the claims and their equivalents. All variations within the scope of the claims and their equivalents are included in the disclosure.