Abstract:
An apparatus for decontaminating a region within an enclosure. The apparatus comprises a conduit having a passageway therethrough that defines a path for a carrier gas. A plurality of tube sections, each of the tube sections having an opening extending therethrough, is selectively movable into and out of a gap in the conduit. A heating element is disposed in one of the tube sections and is operable to heat the carrier gas flowing therethrough. A destroyer is disposed in another of the tube sections and is operable to destroy sterilant in the carrier gas. A controller controls movement of the tube sections into and out of the gap.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/921,586, filed on Dec. 30, 2013, which is fully incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to decontamination systems, and more particularly to a vapor-phase decontamination system for decontaminating an enclosed region or space. 
       BACKGROUND OF THE INVENTION 
       [0003]    A biosafety cabinet (BSC) is an enclosed, ventilated laboratory workspace that allows laboratory workers to safely work with materials contaminated with (or potentially contaminated with) pathogens. The primary purpose of a biosafety cabinet is to protect laboratory workers and the surrounding environment from pathogens. 
         [0004]    The U.S. Centers for Disease Control and Prevention (CDC) classifies biosafety cabinets into three classes. Most biosafety cabinets are a Class II, Type A2 cabinet. The principle of operation of these biosafety cabinets involves using a fan mounted in the top of a cabinet to draw a curtain of sterile air over the materials that are being handled. The air is circulated through a HEPA filter and then directed down underneath a work surface and back up to the top of the cabinet. A certain percentage of the air in the cabinet that is exhausted (after passing through the HEPA filter) is made up by air being drawn into the front of the cabinet underneath the workspace. The air being drawn into the work area acts as a barrier to potentially contaminated air coming back out to the operator. A Class II, Type A2 biosafety cabinet typically recirculates about 70% of the air used therein. 
         [0005]    To ensure proper operation, the biosafety cabinet, particularly the HEPA filter, must be periodically cleaned and tested. Prior to servicing the biosafety cabinet, the enclosure must be decontaminated to protect service personnel from exposure to pathogens that may have been collected in the workspace of the cabinet or the filter. 
         [0006]    A conventional method of decontaminating biosafety cabinets consists of sealing, i.e., closing, the opening to the workspace, and heating, i.e. boiling, formaldehyde within the enclosure. The formaldehyde vapors decontaminate the exposed surfaces of the workspace. A problem with this method of decontamination is that a residue is produced by the boiling of formaldehyde. The residue must be physically removed from the surfaces of the enclosure by a subsequent cleaning process. Moreover, it is difficult to decontaminate the HEPA filter using a formaldehyde process as described above. In this respect, when formaldehyde is used, a system blower is typically energized for a very short interval to draw some the vaporized formaldehyde into the filter. However, if the blower is allowed to operate too long, the aforementioned residue is collected within the HEPA filter and can clog the filter, thereby requiring its replacement. Too little exposure of the formaldehyde vapor can result in the filter not being completely decontaminated. Moreover, because the blower can be operated for only a relatively short period of time, the enclosure and the air passages downstream of the blower and the HEPA filter are not assuredly decontaminated. 
         [0007]    The present invention overcomes this and other problems and provides a method and apparatus for decontaminating an enclosure, particularly a biosafety cabinet, that effectively and efficiently decontaminates the enclosure of a biosafety cabinet as well as the HEPA filter and lower passageways therein. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with a preferred embodiment of the present invention, there is provided an apparatus for decontaminating a region within an enclosure. The apparatus comprises a conduit having a passageway therethrough. The passageway defines a path for a carrier gas. The conduit has a first end and a second end, each of the ends being connectable to an enclosure to define a closed-loop path that includes a region defined by the enclosure. A blower is attached to the conduit for re-circulating a carrier gas into, through and out of the region of the enclosure. A nozzle injects a sterilant into the conduit. A space or gap is defined in the conduit. A plurality of tube sections is provided. Each of the tube sections defines a tubular chamber having an opening therethrough and each of the chambers is selectively movable into and out of the gap in the conduit. An opening in a tubular chamber is aligned with the passageway in the conduit when the chamber is disposed in the gap, wherein the opening in the tubular chamber is aligned with the passageway in the conduit. A heating element is disposed in one of the tubular chambers and is operable to heat the carrier gas flowing therethrough. A destroyer is disposed in another of the tubular chambers and is operable to destroy sterilant in the carrier gas. A controller controls movement of the tubular chambers into and out of the gap and the operating of the heating element and the nozzle. 
         [0009]    An advantage of the present invention is a system that can decontaminate a biosafety cabinet. 
         [0010]    Another advantage of the present invention is a decontamination system that does not require subsequent cleanings of the biosafety cabinet following a decontamination cycle. 
         [0011]    A still further advantage of the present invention is a decontamination system as described above that can decontaminate a filter within a biosafety decontamination cabinet without leaving a residue. 
         [0012]    Another advantage of the present invention is a decontamination system as described above wherein the entire interior of the biosafety cabinet is exposed to the decontaminant. 
         [0013]    A still further advantage of the present invention is a decontamination system as described above that utilizes a recirculation system within a biosafety cabinet to circulate a sterilant through the entire biosafety cabinet. 
         [0014]    A still further advantage of the present invention is a decontamination system as described above, wherein the recirculation system within the biosafety cabinet operates continuously during a decontamination cycle. 
         [0015]    A still further advantage of the present invention is a decontamination system that utilizes a vaporized sterilant. 
         [0016]    A still further advantage of the present invention is a vaporized hydrogen peroxide system that utilizes a solution comprised of 59% hydrogen peroxide and 41% water to create vaporized hydrogen peroxide. 
         [0017]    A still further advantage of the present invention is a decontamination system as described above which is portable. 
         [0018]    A still further advantage of the present invention is a decontamination system as described above that includes connections for connecting the decontamination system to a biosafety cabinet that fully encloses the workspace of the biosafety cabinet and produces a closed-loop vaporous circulation system. 
         [0019]    A still further advantage of the present invention is a compact decontamination system for decontaminating a room or region. 
         [0020]    Another advantage of the present invention is a decontamination system as described above that is portable. 
         [0021]    A still further advantage of the present invention is a decontamination system as described above that includes a plurality of movable tubular chambers that are each used to perform a phase of a decontamination cycle. 
         [0022]    A still further advantage of the present invention is a decontamination system as described above that utilizes a vaporous sterilant. 
         [0023]    Another advantage of the present invention is a decontamination system as described above that utilizes vaporous hydrogen peroxide. 
         [0024]    A still further advantage of the present invention is a decontamination system as described above having a plurality of tubular passages that are each indexable into a path of a carrier gas. 
         [0025]    A still further advantage of the present invention is a decontamination system as described above that has a replaceable canister containing a desiccant. 
         [0026]    A still further advantage of the present invention is a decontamination system as described above that is suitable for decontaminating a biosafety cabinet. 
         [0027]    A still further advantage of the present invention is a decontamination system as described above that can decontaminate the air circulation system of a biosafety cabinet downstream of the blower. 
         [0028]    These and other advantages will become apparent from the following description of a preferred embodiment taken together with the accompanying drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein: 
           [0030]      FIG. 1  is a perspective view showing a decontamination system according to the present invention connected to a biosafety cabinet; 
           [0031]      FIG. 2  is an enlarged, top perspective view of the decontamination system, illustrating a preferred embodiment of the present invention; 
           [0032]      FIG. 3  is a perspective view of the decontamination system shown in  FIG. 2  showing a chemical sterilant container removed therefrom; 
           [0033]      FIG. 4  is a sectional view taken along lines  4 - 4  of  FIG. 2 ; 
           [0034]      FIG. 5  is a sectional view taken along lines  5 - 5  of  FIG. 4 , showing in cross-section three (3) tube sections that form part of a tube assembly; 
           [0035]      FIG. 6  is a sectional view taken along lines  6 - 6  of  FIG. 5 , showing a tube section containing a desiccant canister aligned with a first and second tubular members that form part of a conduit system for conveying a carrier gas to a room or region; 
           [0036]      FIG. 7  is a sectional view showing a tube section containing a heating element aligned with the first and second tubular members that form a conduit of the decontamination system; 
           [0037]      FIG. 8  is a sectional view showing a desiccant canister being removed from one of the tube sections of the tube assembly; 
           [0038]      FIG. 9  is a sectional view taken along lines  9 - 9  of  FIG. 6 ; 
           [0039]      FIG. 10  is a sectional view of a damper assembly mounted to the exhaust duct of a biosafety cabinet, showing a damper element in an open position allowing a portion of the air that circulates through the biosafety cabinet to be exhausted from the biosafety cabinet; 
           [0040]      FIG. 11  is a sectional view of the damper assembly shown in  FIG. 10 , showing the damper element in a second position wherein a portion of the air circulated through the biosafety cabinet is directed to a exit port; and 
           [0041]      FIG. 12  is a schematic view showing a closed loop circulation system that is established when the decontamination unit is connected to a biosafety cabinet. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0042]    Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting same,  FIG. 1  shows a decontamination system  10 , according to a preferred embodiment of the present invention. Decontamination system  10  is particularly applicable in decontaminating a Class II, Type A2 biosafety cabinet, and will be described with particular reference thereto. However, as will be appreciated from a further reading of the present specification, the decontamination system may also find advantageous application in decontaminating other types of biosafety cabinets, as well as decontaminating other types of enclosed regions or spaces. 
         [0043]    In  FIG. 1 , a Class II, Type A2 biosafety cabinet  20  is shown. Biosafety cabinet  20 , in and of itself, forms no part of the present invention. Accordingly, biosafety cabinet  20  shall not be described in great detail. In general, biosafety cabinet  20  is comprised of a rectangular enclosure  22  elevated above the floor  14 . In the drawings, biosafety cabinet  20  is shown supported on a table or countertop  12 . Enclosure  22  includes a clear front panel  24  having an opening  26  therebelow that provides access to a workspace  28  within biosafety cabinet  20 . Workspace  28  is defined by an inner housing  32 , best seen in  FIG. 12  that is located in a lower portion of rectangular enclosure  22 . Inner housing  32  separates workspace  28  from an upper space  34  that contains a blower  36  and HEPA filters  38 A and  38 B. A duct  42  is defined within biosafety cabinet  20  underneath and around one side of inner housing  32 . A bottom wall  32   a  of inner housing  32  includes slots, or openings  44 , that communicate with duct  42 . Blower  36  is operable to circulate air throughout enclosure  22 , over and in front of workspace  28 , as illustrated by the arrows as shown in  FIG. 12 . An exhaust port  46  is defined in an upper wall  22   a  of enclosure  22  to allow a portion of the air circulated within biosafety cabinet  20  to be exhausted from biosafety cabinet  20 . Exhaust port  46  communicates with an exhaust duct  48 . The air exhausted from biosafety cabinet  20  is replaced by air drawn into opening  26  in front panel  24  of biosafety cabinet  20 . The air being drawn into workspace  28  acts as a barrier to block potentially contaminated air from escaping out of biosafety cabinet  20 , as is conventionally known. Blower  36  is operable to circulate air through biosafety cabinet  20  with a portion of the air inside biosafety cabinet  20  being exhausted and replaced with new air drawn into biosafety cabinet  20 , as described above. 
         [0044]    Referring now to  FIGS. 2-8 , decontamination system  10  is best seen. In the embodiment shown, decontamination system  10  is contained within a portable case  60  having a grip or handle  62 . Case  60  is comprised of a base portion  72  and a lid portion  74 . Base portion  72  defines a generally rectangular cavity that is dimensioned to receive the operative components of decontamination system  10 . Lid portion  74  is hinged to base portion  72 . Latches  76  on lid portion  74  are provided to securely attach lid portion  74  and base portion  72  together and to allow case  60  to completely enclose decontamination system  10 . 
         [0045]    A frame structure  82 , best seen in  FIG. 4 , is disposed within base portion  72  of case  60 . Frame  82  supports a generally flat panel  84 . Mounted to flat panel  84 , and disposed within base portion  72  of case  60 , is a generally rectangular housing  92  that defines an inner chamber  92   a.  Housing  92  is attached to the underside of flat panel  84  by conventional fasteners, as best seen in  FIG. 5 . An opening  94  (best seen in  FIG. 3 ), formed through panel  84 , communicates with inner chamber  92   a  of housing  92 , to allow access thereto. 
         [0046]    In the embodiment shown, housing  92  is generally rectangular in shape. A first tubular member  112  extends from one face of housing  92 . A second tubular member  122  extends from an opposing face of housing  92 . In the embodiment shown, first tubular member  112  is a straight, cylindrical tube, defining a first passageway  112   a.  Second tubular member  122  is an L-shaped, cylindrical tube, defining a second passageway  122   a.  In accordance with one aspect of the present invention, first tubular member  112  is generally aligned with second tubular member  122 , such that the first passageway  112   a  is in alignment with, but spaced from, second passageway  122   a.  In this respect, a space or gap, defined by chamber  92   a  of housing  92 , exists between first and second tubular members  112 ,  122 . 
         [0047]    The free end of L-shaped, second tubular member  122  extends upward through flat panel  84 , as best seen in  FIG. 4 . The free end of second tubular member  122  includes a tubular collar  132  and defines a system outlet  134 . Collar  132  has an annular groove  136  formed in the outer surface thereof. 
         [0048]    A blower  142  is mounted to the underside of panel  84 , adjacent to housing  92 . Blower  142  has an inlet  142   a  connected to a tubular connector  152  extending through panel  84  and defining a system inlet  154 . An outlet from blower  142  is connected to the free end of first tubular member  112 . A gasket  146  is disposed between outlet  142   b  of blower  142  and the free end of first tubular member  112 . 
         [0049]    A cup-shaped, reagent receiving well  162  is mounted to the underside of panel  84 , adjacent to housing  92 . An opening  164  in panel  84  communicates with reagent receiving well  162 . Well  162  is dimensioned to receive a closed container  166  containing a liquid sterilant. Container  166  is generally a cup-shaped receptacle  166   a , formed preferably of plastic having a foil or mylar layer  166   b  covering and enclosing container  166   a.  A cap  172 , having a siphoning tube  174  extending therefrom, is dimensioned to be positioned over well  162 . Siphoning tube  174  is dimensioned to puncture layer  166   b  and to extend into sterilant container  166 , as shall be described in greater detail below. Flexible tubing  182  is connected to cap  172  and is in fluid communication with siphoning tube  174  extending from cap  172 . Tubing  182  is connected to an inlet of a sterilant injection system. The sterilant injection system (not shown) is basically comprised of a pump (not shown) having an outlet tubing  184  connected to an atomizing nozzle  186  disposed within the first passageway of first tubular member  112 . Atomizing nozzle  186 , best seen in  FIG. 6 , is supported on an arm extending into first passageway  112   a.    
         [0050]    A hinge  192  connects a cover plate  194  to the upper surface of panel  84 . Cover plate  194  is dimensioned to cover opening  94  to chamber  92   a  and opening  164  to reagent receiving well  162 . In this respect, cover plate  194  is movable between a closed position covering openings  94 ,  164 , as shown in  FIG. 2 , and an opened position allowing access to openings  94 ,  164 , as shown in  FIG. 3 . A continuous, generally rectangular seal  196  is provided on the underside of cover plate  194  and is dimensioned to surround opening  94  and to form a seal between panel  84  and cover plate  194  when cover plate  194  is in the closed position. 
         [0051]    Locking elements  197  on cover plate  194  are provided to be received in openings  198  in panel  84  to lock cover plate  194  in the closed position. A tab  199  on cover plate  194  is dimensioned to be received in a slot  195  in panel  84 . A sensor (not shown) on the underside of panel  84  is provided to sense when tab  199  is within slot  195 , which indicates that cover plate  194  is in a closed position. 
         [0052]    Referring now to  FIGS. 5-8 , a tube assembly  210 , comprised of a plurality of tube sections, is shown. In the embodiment shown, three (3) side-by-side tube sections  212 ,  214 ,  216  are shown. Each tube section  212 ,  214 ,  216  defines a tubular chamber  212 A,  214 A,  216 A. In the embodiment shown, each tube section is connected to each of the other two (2) tube sections to form a generally triangular configuration when viewed in cross-section, as best seen in  FIG. 5 . Tube assembly  210  is symmetrical by a central axis “A.” A shaft  222  extends along central axis “A” and is connected to each tube section  212 ,  214 ,  216 . Shaft  222  of tube assembly  210  is mounted to housing  92 , such that tube assembly  210  is rotatable about axis “A.” Shaft  222  is disposed, i.e., positioned, within housing  92  such that each of the tube sections can be moved, i.e., rotated, into alignment with passageways  112   a,    122   a  defined between the ends of first tubular member  112  and second tubular member  122 . When aligned with first and second tubular members  112 ,  122 , a tubular chamber of a tube section essentially completes a path defined by passageways  112   a,    122   a  of first tubular member  112  and second tubular member  122 . 
         [0053]    One end of shaft  222  is connected to a motor  224  that is schematically illustrated in the drawings. Motor  224  is mounted to outer surface of housing  92 . Motor  224  is operable to rotate tube assembly  210  about axis “A,” wherein one of tube sections  212 ,  214 ,  216  may be aligned with first and second tubular members  112 ,  122 . Each tube section  212 ,  214 ,  216  of tube assembly  210  is dimensioned such that each end of a tube section  212 ,  214 ,  216  mates closely with the ends of first and second tubular members  112 ,  122  that communicate with inner chamber  92   a  of housing  92 . When a tube section  212 ,  214 ,  216  is aligned with tubular members  112 ,  122 , the aligned tube section is in an “operative position” and a generally continuous path is defined through decontamination system  10 . The path extends through first tubular member  112 , through an aligned tube section of the tube assembly and continues through to second tubular member  122 . 
         [0054]    Tube section  212  of tube assembly  210  contains an atomization tube  231  and a heating element  232 . Atomization tube  231  is disposed within tube section  212 . Atomization tube  231  is dimensioned such that a gap  233  or space is defined between tube section  212  and atomization tube  231 , as best seen in  FIG. 7 . In the embodiment shown, heating element  232  is coiled into a generally conical shape, best seen in  FIG. 7 . At least one coil  232   a  of heating element  232  is in contact with the inner surface of atomization tube  231 . The heating element is coiled around a cylindrical pin  234  having a conical end portion  236 . Heating element  232  is mounted on a support bracket  238  to be centrally located within tubular chamber  212 A of tube section  212 , with pin  234  facing blower  142 . Electrical leads  239 A,  239 B extend from heating element  232  through the wall of tube section  212 . 
         [0055]    Tube section  214  of tube assembly  210  contains a desiccant canister  242 . Desiccant canister  242  contains a material that absorbs moisture. The axial ends of canister  242  are perforated to allow air to flow therethrough. According to one aspect of the present invention, tube section  214  is comprised of two tube section halves  214   a,    214   b.  A hinge  244  connects tube section half  214   a  to half tube section  214   b  and allows tube  214  to be opened to allow removal and replacement of a desiccant canister  242  therein. 
         [0056]    A latch element  246 , best seen in  FIG. 8 , is attached to the outer surface of tube section half  214   b  of tube section  214 . Latch element  246  is formed from a strip of resilient material, such as a spring metal, that is formed to have a U-shaped section  246   a  that defines a tab. U-shaped section  246   a  is dimensioned to snap lock into a slot  248  formed in tube section half  214   a.  Latch  246  releasably locks tube section haves  214   a,    214   b  together to secure desiccant canister  242 . 
         [0057]    As shown in  FIG. 8 , a desiccant canister  242  can easily be inserted or removed from tube section  214 , when tube section  214  is in alignment with first and second tubular members  112 ,  122 , by releasing latch  246  and separating tube section halves  214   a,    214   b.    
         [0058]    Tube section  216  contains a destroyer cartridge  252  therein. Destroyer cartridge  252  contains a material operable to break down a vapor sterilant as the vapor sterilant flows through second tubular chamber  216 A. In the embodiment shown, destroyer cartridge  252  is a cylindrical container having perforations formed through the ends thereof to allow axial air flow therethrough. 
         [0059]    A temperature sensor  262  and a humidity sensor  264  are disposed within decontamination system  10 . Temperature sensor  262  and humidity sensor  264  are preferably disposed within passageway  112   a  of first tubular member  112 . 
         [0060]    A controller  270 , schematically illustrated in the drawings, is provided within decontamination system  10 . Controller  270  is connected to temperature sensor  262  and humidity sensor  264  to receive signals therefrom. Controller  270  is also connected to blower motor  144 , motor  224  of tube assembly  210 , heating element  232  that is disposed within tube section  212 , and sterilant injection pump (not shown) to control the respective operations thereof. A control panel  272  having an interface display  274  is mounted to panel  84  and is connected to controller  270  to allow user input and control. Power to decontamination system  10  is provided by an electrical cable  276  connectable to controller  270  and to an external power source, i.e., a building outlet, (not shown). A serial connection port  278  is provided on panel  84  and is connected to controller  270  to allow external devices to connect to controller  270 . 
         [0061]    Two (2) flexible hoses  282 ,  284  are provided to connect decontamination system  10  to biosafety cabinet  20 . Each flexible hose includes cylindrical sleeve  286  at the ends thereof. Sleeves  286  are dimensioned to be attached in a tight-fitting relationship to tubular collars  132 ,  152  on second and first tubular members  122 ,  112 , respectively. One end of first flexible hose  282  is connected to a panel  292  that is attached to biosafety cabinet  20 . Panel  292  is dimensioned to cover and enclose opening  26  to biosafety cabinet  20 . In this respect, panel  292  is generally rectangular in shape and sized to cover opening  26  to biosafety cabinet  20 . Panel  292  is attached to opening  26  of biosafety cabinet  20  by conventional fasteners, tape, or magnetic means (not shown). Panel  292  has a tubular connector  296  extending therefrom, that is dimensioned to receive cylindrical sleeve  286  on the end of first flexible hose  288 . Panel  292  is preferably comprised of a polymer material. 
         [0062]    Second flexible hose  284  is longer than first hose  282 , as best seen in  FIG. 1 . One end of hose  284  is attached to tubular collar  152  that is connected to blower inlet  142   a.  The other end of second flexible hose  284  is connected to a tubular connector  316  on a damper assembly  310  that is connected to exhaust duct  48  of biosafety cabinet  20 . 
         [0063]    Damper assembly  310 , best seen in  FIGS. 10 and 11 , is installed between exhaust port  46  and exhaust duct  48  of biosafety cabinet  20  to control air exhausted therefrom. Damper assembly  310  is generally comprised of a housing  312  defining an inner cavity  314  that communicates with exhaust port  46  and a passageway  48   a  defined by exhaust duct  48 . A tubular connector  316 , that is similar in design to tubular collars  132 ,  152 , extends from one side of housing  312 . Connector  316  defines an inner passageway  316   a  that communicates with inner cavity  314  of housing  312 . A damper plate  318  is pivotally mounted within housing  312  to be movable between a first position obstructing and covering passageway  316   a,  as shown in  FIG. 10 , and a second position, obstructing and covering passageway  48   a  in exhaust duct  48 , as shown in  FIG. 11 . 
         [0064]    Aspects of the present invention shall now be described with reference to the operation of decontamination system  10 . Prior to initiating a decontamination cycle, panel  292  is attached to biosafety cabinet  20  to cover access opening  26  to workspace  28 . Panel  292  is secured to biosafety cabinet  20  to completely seal opening  26 . Hoses  282 ,  284  are then connected to decontamination system  10  and biosafety cabinet  20 , as illustrated in  FIG. 1 . Damper  318  is moved to its second position, as shown in  FIG. 11 , to close off exhaust duct  48  and connect the interior of biosafety cabinet  20  to passageway  316   a  and hose  284 . 
         [0065]    With the two flexible hoses  282 ,  284  connecting decontamination system  10  to biosafety cabinet  20  and damper plate  318  in its second position, a closed-loop circulation path is created from decontamination system  10  through first flexible hose  282 , though biosafety cabinet  20  and back to decontamination system  10  through second flexible hose  284 . 
         [0066]    Decontamination system  10  is dimensioned to utilize an enclosed, prepackaged liquid sterilant container  166 . A sterilant container  166  is placed into cup-shaped reagent receiving well  162  through opening  164  in flat panel  84  of decontamination system  10 . According to another aspect of the present invention, it is contemplated that sterilant container  166  includes an RFID tag, or other means of encoded data, on the side of container  166  that can be read by an RFID reader (not shown) that is connected to controller  270 . Encoded information from the RFID tag on sterilant container  166 , including the volume of the sterilant enclosed, an expiration date and the like, can be transmitted from the barcode scanner to controller  270  of decontamination system  10  prior to initiating a decontamination cycle. 
         [0067]    According to a preferred embodiment of the present invention, decontamination system  10  utilizes a sterilant solution comprised of hydrogen peroxide and water. In a more preferred embodiment, a sterilant solution comprised of 59% hydrogen peroxide by weight and 41% water by weight is used. However, other concentrations of hydrogen peroxide and water are contemplated. 
         [0068]    During the operation of decontamination system  10 , blower  36  of biosafety cabinet  20  is operated to help the circulation of sterilant throughout biosafety cabinet  20 , and particularly, through the HEPA filter  38  and through upper space  34  of biosafety cabinet  20 , as shall be described in greater detail below. 
         [0069]    Controller  270  is programmed to perform a decontamination cycle that includes: a heating phase; a drying phase; a conditioning phase; a decontamination phase; and an aeration phase. When a decontamination cycle is first initiated, controller  270  causes motor  224  of tube assembly  210  to move tube section  212 , that contains heating element  232  into alignment with first and second tubular members  112 ,  122 , as illustrated in  FIG. 7 . Controller  270  then initiates the “heating phase” by energizing blower motor  144  that cause blower  142  to circulate air (the carrier gas) past heating element  232 . The air is conveyed through biosafety cabinet  20  along the closed loop circulation path, as illustrated in  FIG. 12 . Heating element  232  is energized to heat the air circulated through biosafety cabinet  20  and through decontamination system  10 . Temperature sensor  262  within passageway  112   a  of first tubular member  112  senses the temperature of the air, i.e., the carrier gas, as it is circulated through biosafety cabinet  20  and decontamination system  10 . 
         [0070]    When the circulated air reaches a desired temperature, about 31° C., heating element  232  is de-energized and motor  224  of tube section assembly  210  is energized to index tube section  214  containing desiccant canister  242  into position in alignment with first and second tubular members  112 ,  122 . With second tube section  214  containing desiccant canister  242  now forming part of the closed loop circulation path, the “drying phase” is initiated. Moisture within the air flowing through biosafety cabinet  20  and decontamination system  10  is removed as the air passes through desiccant canister  242 . Humidity sensor  264  within first tubular member  112  monitors the humidity of the air flowing through first tubular member  112  and, thus, provides an indication of the humidity within biosafety cabinet  20 . In accordance with the preferred embodiment, the drying phase continues until the air circulating through the closed loop circulation path, i.e., through biosafety cabinet  20 , attains a relative humidity of about 15%. 
         [0071]    Once a desired humidity level is reached, a “conditioning phase” is initiated. Motor  224  of tube assembly  210  is energized to return tube section  212  containing heating element  232  into position in alignment with first and second tubular members  112 ,  122 . Controller  270  then causes the sterilant injection system, and, more specifically the sterilant pump (not shown), to inject the liquid sterilant from sterilant container  166  to atomizing nozzle  186  within first tubular member  112 , thereby creating an atomized mist within first passageway  112   a.  The air circulating through the closed loop circulation path defined by decontamination system  10  and biosafety cabinet  20  was previously heated and dried during the drying phase. The atomized hydrogen peroxide vaporizes within decontamination system  10 . The vaporization process is a hybrid of conventionally known flash vaporization where the liquid hydrogen peroxide is vaporized on a heating plate/element. According to the present invention, the vaporization occurs in several ways. The atomized hydrogen peroxide is introduced into the heated airstream where latent heat is extracted from the airstream to vaporize the hydrogen peroxide. Remaining atomized hydrogen peroxide is flashed vaporized from contact conical end portion  236  and heater element  232 . Vaporization is also conducted from contact of the atomized hydrogen peroxide with the inner surface of atomization tube  231  as a result of the transfer of heat from the contact of coil  232   a  of heating element  232  to the inner surface of atomization tube  231 . 
         [0072]    The vaporized hydrogen peroxide (VHP) is introduced into the closed-loop circulation path and is conveyed through first flexible hose  282  into work space  28  of biosafety cabinet  20 . Since the blower system of biosafety cabinet  20  is operating, the vaporized hydrogen peroxide (VHP) is drawn into upper space  34  where blower  36  in biosafety cabinet  20  circulates 70% of the carrier gas and the vaporized hydrogen peroxide (VHP) contained therein through duct  42  through HEPA filter  38 A, to the underside of workspace  28  and back into workspace  28 , as illustrated by the arrow in  FIG. 12 . 
         [0073]    30% of the carrier gas and associated vaporized hydrogen peroxide (VHP) is drawn through HEPA filter  38 B (exhaust) and through second flexible hose  284  by blower  144  of decontamination system  10  and biosafety cabinet blower  36 . In other words, the vaporized hydrogen peroxide (VHP) is introduced into a closed-loop path and is conveyed through flexible hoses  282 ,  284  by the carrier gas (air) into and back out of biosafety cabinet  20  before it is returned to decontamination system  10 . During the conditioning phase, vaporized hydrogen peroxide (VHP) is injected into decontamination system  10  at a relatively high rate to bring the vaporized hydrogen peroxide (VHP) level within biosafety cabinet  20  to a desired level in a short period of time. During the conditioning phase, blower  142  and cabinet blower  36  causes the air within the closed loop path to circulate continuously through first and second flexible hoses  282 ,  284  and through biosafety cabinet  20 . As a result of the continuous circulation of the vaporized hydrogen peroxide (VHP) along the closed-loop path (created by connecting decontamination system  10 , first and second flexible hoses  282 ,  284  and biosafety cabinet  20 ), the concentration of vaporized hydrogen peroxide (VHP) in biosafety cabinet  20  increases more rapidly than it would if vaporized hydrogen peroxide (VHP) exiting biosafety cabinet  20  was destroyed and exhausted. In other words, the vaporized hydrogen peroxide (VHP) flowing through the closed-loop path continuously circulates through decontamination system  10  and past atomizing nozzle  186  where additional vaporized hydrogen peroxide (VHP) is generated and added to the air stream. The conditioning phase is completed when a predetermined concentration of vaporized hydrogen peroxide has been established within the closed loop system. 
         [0074]    After the conditioning phase is completed, the decontamination phase is initiated. During the decontamination phase, the sterilant injection rate to atomizing nozzle  186  is decreased to maintain the concentration of vaporized hydrogen peroxide (VHP) at the desired parts per million (ppm) level. The decontamination phase is run for a predetermined period of time, preferably with the vaporized hydrogen peroxide (VHP) concentration remaining constant, at a level sufficient to effect the desired or decontamination of the interior of biosafety cabinet  20 . In this respect, because the blower within biosafety cabinet  20  assists in the circulation of the vaporized hydrogen peroxide (VHP) throughout biosafety cabinet  20  and, more importantly, HEPA filter(s)  38  of biosafety cabinet  20 , decontamination of the entire interior of biosafety cabinet  20  is performed. After the decontamination phase is completed, controller  270  causes the pump of the injection system to shut down, thereby shutting off the flow of additional sterilant to atomizing nozzle  186 . 
         [0075]    Following completion of the decontamination phase, an aeration phase is initiated. At the start of the aeration phase, controller  270  causes tube assembly  210  to rotate tube section  216 , containing the destroyer material, into alignment with first and second tubular members  112 ,  122 . Blower motor  144  of decontamination system  10  and blower  36  of biosafety cabinet  20  continue to operate causing the carrier air to continuously circulate along the closed-loop path, wherein the air is forced through and past the destroyer material. Contact with the destroyer material causes the vaporized hydrogen peroxide to break down into water and oxygen. During the aeration phase, blower  142  continues to operate until the vaporized hydrogen peroxide (VHP) level is reduced to an allowable threshold (about 1 ppm). 
         [0076]    The present invention provides a compact decontamination system  10  that allows for the decontamination of biosafety cabinets or other similar spaces. By utilizing the circulation system of a biosafety cabinet  20  during the decontamination cycle, the decontamination system  10  can contain a smaller blower, thereby reducing the size, as well as the weight, of decontamination system  10 . Still further, tube sections  212 ,  214 ,  216  forming tube assembly  210  need not sealingly engage the ends of first and second tubular members  112 ,  122  when a tube section is indexed in alignment. In this respect, because housing  92  surrounding tube assembly  210  is totally enclosed, any leaks between tube sections  212 ,  214 ,  216  and the first and second tubular members  112 ,  122  is contained within enclosed housing  92 . In other words, any vaporized hydrogen peroxide (VHP) generated that may be forced into enclosed housing  92  would be later destroyed during the aeration phase of the decontamination cycle. 
         [0077]    The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purposes of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.