Patent Document

This application is a continuation-in-part of U.S. application Ser. No. 10/185,031 filed Jun. 28, 2002, now abandoned the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to sterilization of articles with a vapor sterilant, and more particularly to sterilization of articles in which the vapor sterilant is drawn through a container holding the articles. 
     BACKGROUND OF THE INVENTION 
     It is known to sterilize articles with a vaporized chemical sterilant, such as hydrogen peroxide, peracetic acid and glutaraldehyde. Wu et al. U.S. Pat. No. 6,365,102, incorporated herein by reference, describes a hydrogen peroxide/gas plasma sterilization system comprising a vacuum chamber, source of hydrogen peroxide vapor and a source of RF energy to create a plasma. Such systems marketed under the name STERRAD® are available from Advanced Sterilization Products division of Ethicon, Inc. in Irvine, Calif. 
     Getting the vapor into contact with the items to be sterilized is a concern. Typically, the low pressures (0.5 torr to 10.0 torr) inside of the chamber promotes quick diffusion of the sterilant vapor to all areas therein. However, improving the flow into the container can benefit the sterilization efficiency. Applicants have achieved this goal in a fashion which may be employed with most of the commercially available containers in a novel approach to employing parts of the sterilization cycle already present to flow some of the sterilant vapor through the container. 
     SUMMARY OF THE INVENTION 
     A sterilization system according to the present invention comprises a sterilization chamber for receiving a container having an article to be sterilized therein. A source of sterilant connects to the sterilization chamber. A vacuum pump connects to the sterilization chamber. Either the source of sterilant, or the vacuum pump, or both, connect to the chamber via a one or more conduits having an interface with the container. This promotes ingress of sterilant into the container, sterilant may be flowed directly into the container via the conduit or exhausted from the chamber through the container via the conduit. 
     In one embodiment of the sterilization system the vacuum pump connects to the chamber via the conduit. In another embodiment of the sterilization system the source of sterilant connects to the chamber via the conduit. In a further embodimetn both the vacuum pump and the source of sterilant connect to the chamber via the conduit, each of the vacuum pump and source of sterilant having a valve between itself and the conduit whereby to isolate itself from the conduit. 
     Preferably, the interface comprises an opening into the conduit and an opening into the container, the opening into the conduit being adjacent the opening into the container. The container need not attach to the conduit at the interface with a physical connection, but may merely be adjacent or abut at the interface. 
     Preferably, the sterilant comprises a chemical vapor sterilant. 
     In one embodiment, the interface is removable from the chamber. One advantage of this is to allow different interfaces to be used within the chamber for use with differently sized or shaped containers. 
     Preferably, the interface comprises a support upon which can rest the container, the support having one or more openings facing the container, the one or more openings being in fluid communication with the conduit. The support can have an upper surface upon which rests the container, with the one or more openings penetrating the upper surface. 
     It may be desirable for the manifold to have a plurality of supporting surfaces within the chamber upon which can rest the container and additional containers, with the interface having openings on the supporting surfaces into the manifold. 
     Preferably, the source of sterilant comprises a vaporizer in fluid communication with the chamber. 
     In one embodiment the container has a manifold inside in fluid communication with the conduit and adapted to receive a lumened device therethrough whereby to promote ingress of sterilant through the lumened device. 
     A method for sterilizing an article according to the present invention comprises the steps of: 
     placing the article into a container; 
     placing the container into a chamber; 
     admitting a sterilant into the chamber; and 
     enhancing penetration of sterilant into the container by performing at least one of the following steps:
         a) exhausting at least a portion of an atmosphere within the container directly out of the chamber and thereby drawing sterilant that is in the chamber yet exterior of the container into the container;   b) admitting at least a portion of the sterilant directly into the container.       

     In one embodiment of the method a conduit having an interface with the container leads to a vacuum pump and step a) is performed through the conduit. In an alternative embodiment, a conduit having an interface with the container and leads to a source of sterilant and step b) is performed through the conduit. 
     The step of admitting the sterilant into the chamber can comprise vaporizing a sterilant solution to create a chemical vapor sterilant and further comprising the step of exhausting a portion of the sterilant through the container while admitting the vapor sterilant into the chamber. 
     Preferably,the container has an opening on a surface thereof and a conduit has an opening therein and the method includes the step of placing the opening on the container adjacent the opening on the conduit. 
     In one embodiment the article comprises a lumen and the method includes the steps of providing a conduit having an interface with the container and leading to a vacuum pump and performing step a) through the conduit, connecting the lumen to a manifold in the container, and exhausting a portion of the sterilant through the lumen via the manifold. In another embodiment in which the article comprises a lumen the method includes the steps of providing a conduit having an interface with the container and leading to a source of sterilant and performing step b) through the conduit, connecting the lumen to a manifold in the container, and introducing at least a portion of the sterilant through the lumen via the manifold. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a sterilization system according to the present invention; 
         FIG. 2  is a block diagram of a vaporizer and diffusion path of the sterilization system of  FIG. 1 ; 
         FIG. 3  is a block diagram of an alternate embodiment of a sterilization system according to the present invention; 
         FIG. 3A  is a block diagram of an alternative embodiment of a sterilization system according to the present invention. 
         FIG. 3B  is a sectional view taken along lines  3 B- 3 B of  FIG. 3A ; 
         FIG. 4  is a block diagram of an alternate embodiment of a sterilization system according to the present invention; 
         FIG. 5  is a block diagram of an alternate embodiment of a sterilization system according to the present invention; 
         FIG. 6  is a section view taken along lines  6 - 6  of  FIG. 5 ; 
         FIG. 7  is a block diagram of an alternate embodiment of a sterilization system according to the present invention; 
         FIG. 8  is a section view taken along lines  8 - 8  of  FIG. 7 ; 
         FIG. 9  is a block diagram of an alternate embodiment of a sterilization system according to the present invention; 
         FIG. 10  is a block diagram of a further embodiment of a sterilization system according to the present invention; and 
         FIG. 11  is a block diagram of a further embodiment of a sterilization system according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows in block diagram form a sterilization system  10  comprising a sterilization chamber  12 , a vaporizer  14 , and a vacuum pump  16 . The vacuum pump is capable of drawing a vacuum on the chamber, preferably as low as 0.5 torr. Between the vacuum pump  16  and the chamber  12 , is preferably located at throttle valve  18  and optionally an orifice plate  20 . Preferably, the throttle valve  18  has good shut-off capability. A pressure gauge  22 , preferably located adjacent to the throttle valve  18 , shows the vacuum in the chamber  12 . A vent valve  23  employing a HEPA antimicrobial filter allows clean sterile air to enter the chamber  12 . The vaporizer  14  connects to the chamber  12  by means of an elongated diffusion path  24 . Turning also to  FIG. 2 , the diffusion path  24  incorporates temperature control elements  26  to control the temperature along the diffusion path  24 . 
     Vaporizers suitable for vaporizing a liquid sterilant such as hydrogen peroxide solution are known in the art. Kohler et al. U.S. Pat. No. 6,106,772 and Nguyen et al. U.S. patent application Ser. No. 09/728,973 filed Dec. 10, 2000, both incorporated herein by reference, illustrate vaporizers suitable for the present application. In its simplest for the vaporizer can comprise a small chamber into which the liquid hydrogen peroxide solution is injected. The low pressure in the vaporizer caused by the vacuum in the chamber causes the hydrogen peroxide solution to vaporize. 
     Preferably, the vaporizer  14  itself incorporates heating elements  28  which control the temperature in the vaporizer to optimize the vaporization process. Preferably, where the vaporizer  14  connects to the diffusion path  24  some form of thermal insulation  30  provided at the interface so that the high temperatures of the vaporizer  14  will not unduly affect the temperature in the diffusion path  24 . The vaporizer  14  and diffusion path  24  are preferably formed of aluminum; the thermal insulation  30  can take the form of a polyvinyl chloride (PVC) joint connecting the two together. 
     Further, it is preferable to include a heater  32  inside the chamber  12 , preferably near a lower portion of the chamber  12  for revaporizing condensed hydrogen peroxide inside the chamber  12 . 
     The chamber  12  preferably includes a mechanism (not shown) to create a plasma therein. Such mechanism can include a source of radio or low frequency energy as described by Jacobs et al. U.S. Pat. No. 4,643,867, or by Platt, Jr. et al. in published U.S. Application Document No. 20020068012, both of which are incorporated herein by reference. 
     The present invention achieves its beneficial effect by allowing some of the hydrogen peroxide which is vaporized out of solution in the vaporizer  14  to condense onto the diffusion path  24 . After most of the hydrogen peroxide solution has vaporized, the temperature control elements  26  raise the temperature of the diffusion path to allow the condensed hydrogen peroxide to re-vaporize. Water has a higher vapor pressure than hydrogen peroxide, thus hydrogen peroxide in the vapor condenses more easily than water. Thus, the material which condenses in the diffusion path will have a higher concentration of hydrogen peroxide than the starting concentration of the hydrogen peroxide solution in the vaporizer  14 . 
     The temperature control elements  26  in simple form can comprise mere electric resistance heaters. In such case, the low ambient temperature of the diffusion path  24  provides the low temperature for condensing hydrogen peroxide thereon, and the control elements  26  later heat the diffusion path  24  to re-vaporize the now more highly concentrated hydrogen peroxide from the diffusion path  24 . Because the vapor pressure of hydrogen peroxide drops with lower temperatures, lower initial temperatures in the diffusion path  24  allows a lower pressure in the chamber  12  without subsequently preventing the condensation of hydrogen peroxide in the diffusion path. Lower chamber pressures promote system efficiency and thus, the temperature control elements  26  can further comprise a chilling component to lower the temperature of the diffusion path below ambient. Suitable chilling components include thermoelectric coolers or a typical mechanical refrigeration system. In such case, the diffusion path  24  would be first chilled, preferably to about 10° C., and then some time after vaporization has begun or even after it has completed, the diffusion path  24  is then heated, preferably up to 50° C. or 110° C. 
     When vertically oriented as in  FIG. 2 , the diffusion path  24  can potentially cause the vaporizing sterilant to condense in cooler regions between the temperature control elements  26  and then re-vaporize as it passes the temperature control element  26 . 
     The following example illustrates the benefits of controlling the heat in the diffusion path. 
     EXAMPLE 1 
     The efficacy tests were conducted by placing a CSR-wrapped tray (3.5″×10″×20″) consisting of representative medical devices and test lumens in a 20-liter aluminum chamber (4.4″×12″×22″). A one-inch stainless steel wire inoculated with at least 1×10 6    Bacillus stearothermophilus  spores was placed in the center of each of the test lumens. The effects with and without temperature control of the diffusion path were investigated with both a TEFLON, poly(tetrafluoroethylene)lumen having an internal diameter of 1 mm and a length of 700 mm, and a stainless steel lumen having an internal diameter of 1 mm, and a length of 500 mm. All lumens were open at both ends. Each of the samples were subjected to a sterilization cycle in a 20 liter vacuum chamber, which was held at 40° C. and 3 torr for 5 minutes. 1.44 ml of a 59% solution of hydrogen peroxide in water was injected into the vaporizer which was held at 60° C. The 5 minute clock then started and the chamber was pumped down to 3 torr, which took less than one minute. In one case the diffusion path  24  had an initial temperature of 30° C. for the first minute while the chamber was evacuated to 3 torr and was then heated to 50° C. to release the condensed peroxide from the diffusion path into the chamber for the remainder of the cycle while pressure was maintained at 3 torr. In the other case, the diffusion path was held at 50° C. throughout the cycle. By maintaining the diffusion path at 50° C., no or little peroxide was retained in the diffusion path. Sterilization effectiveness was measured by incubating the test samples in growth media at 55° C. and checking for growth of the test organism. Table 1 shows the results of these tests. 
     
       
         
               
               
             
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 30° C. 
               
             
          
           
               
                   
                 50° C. 
                 Diffusion 
               
               
                   
                 Diffusion 
                 Path For One 
               
               
                   
                 Path 
                 Minute Then 
               
               
                   
                 Throughout 
                 increased to 
               
             
          
           
               
                 Lumen Type 
                 ID &amp; Length 
                 Process 
                 50° C. 
               
               
                   
               
               
                 Teflon 
                 1 × 700 
                 2/2 
                 0/3 
               
               
                 Stainless 
                 1 × 500 
                 1/2 
                 0/3 
               
               
                 Steel 
               
               
                   
               
             
          
         
       
     
     When the diffusion path temperature was maintained at high temperature throughout the process, all of the samples in the TEFLON lumen tested positive for bacteria growth, indicating failure of sterilization, and one of two samples in the stainless steel lumen tested positive. Under the same conditions, but with an initially lower temperature diffusion path which was heated starting one minute after the diffusion began, none of the samples tested positive. Condensing the peroxide in the diffusion path during the initial vaporization stage and then re-vaporizing the condensed peroxide from the diffusion path into the chamber greatly enhance the efficacy. 
     Additional efficiencies can be achieved by alternating cool and warm regions in the diffusion path  24  as primarily illustrated in  FIG. 2 . The temperature control elements  26 , in simple form heating elements, are spaced apart from one another. Also, preferably, the diffusion path  24  is vertical in this respect. As the hydrogen peroxide solution vaporizes and passes through the diffusion path  24 , it is thought that it may alternately condense and re-vaporize as it passes over the heated and unheated sections of the diffusion path  24 . The diffusion path could alternatively comprise alternating heating and cooling elements. 
     The heater  32  within the chamber  12  acts similarly to the heating of the diffusion path  24 . By controlling the heater  32  temperature, the peroxide can be first condensed on the heater  32  and then re-vaporized into the chamber  12  to concentrate the peroxide. 
     A preferred cycle would be a modification of a cycle described in the Wu et al. U.S. Pat. No. 6,365,102, incorporated herein by reference. A series of pre-plasma energy additions with venting in-between dries moisture from the chamber  12 . A vacuum is then drawn upon the chamber  12  and the hydrogen peroxide solution injected into the vaporizer  14 . Alternatively, the peroxide solution can also be injected at atmospheric pressure. Some of the vaporizing solution condenses upon the cool diffusion path  24 . After a time sufficient for most or all of the hydrogen peroxide solution to vaporize from the vaporizer  14 , the diffusion path  24  is warmed by the temperature control elements  26  and the condensed hydrogen peroxide solution re-vaporizes. At about this time, the throttle valve  18  is closed and the pump  16  turned off to seal the chamber  12 . Much of the water fraction of the hydrogen peroxide solution has thus been drawn out of the chamber  12  by the vacuum pump  16  and the remaining hydrogen peroxide solution which re-vaporizes from the diffusion path  24 , or from the heater  32  in the chamber  12  if present, is of a higher hydrogen peroxide concentration than the starting solution. Preferably, a computer based control system (not shown) controls the functions of the process for ease and repeatability. 
     The hydrogen peroxide vapor thus produced contacts an article  34  or articles  34  in the chamber  12  and effects sterilization thereof. If those articles  34  have diffusion restricted areas, such as long, narrow lumens, it may be preferable to then vent the chamber  12  and allow clean sterile air therein to drive the hydrogen peroxide vapor deeper into the diffusion restricted areas. Then the chamber  12  is again subjected to vacuum and an additional injection of hydrogen peroxide, preferably with the heating sequence on the diffusion path, is repeated. After a time period sufficient to effect sterilization of the article  34 , preferably with a six-log reduction in challenge organisms such as  Bacillus stearothermophilus , a plasma is lit within the chamber  12 , thereby enhancing the sterilization and breaking down the hydrogen peroxide into water and oxygen. 
     The orifice plate  20  can enhance the effect of concentrating the hydrogen peroxide during its vaporization. As described in the Lin et al. U.S. Pat. No. 5,851,485, incorporated herein by reference, a controlled or slow pump-down of the chamber  12  initially draws off more water than hydrogen peroxide from solution as the water has a higher vapor pressure, thereby leaving a higher concentration hydrogen peroxide behind. Controlling the pump-down can be difficult as vacuum pumps generally do not throttle back well and throttle valves in such service are difficult to control and expensive. By placing the orifice plate  20  in the flow path to the pump  16 , the amount of atmosphere from the chamber  12  exhausted by the pump  16  is limited, and by selecting a proper size orifice  36  in the plate  20  can be controlled to a rate which effectively concentrates hydrogen peroxide in the chamber  12 . 
     Turning also to  FIG. 3 , a system  10   a , similar in most respects to the system  10  of  FIGS. 1 and 2 , with like part numbers denoted with an “a” appended thereto, also incorporates an orifice plate  20   a . However, to allow a quick pump-down of the chamber  12   a , yet retain the controlled pump-down benefits of the orifice plate  20   a , it incorporates two path ways from the pump  16   a  to the chamber  12   a . A first pathway  40  contains a throttle valve  42  and a second pathway  44  contains a throttle valve  46  and the orifice plate  20   a . Thus, during initial pump-down the first throttle valve  42  is open leaving the pump  16   a  freely connected to the chamber  12   a . As the chamber  12   a  approaches the vapor pressure of water, the first throttle valve  42  is closed thereby forcing the pump  16   a  to evacuate through the orifice plate  20   a  and thus draw out of the chamber  12   a  at a slower, controlled rate more conducive to preferentially drawing water out of the hydrogen peroxide solution and out of the chamber  12   a.    
     Turning also to  FIGS. 3A and 3B , a system  110  similar to that of  FIG. 1  is shown. Here, rather than use two paths as in the system  10   a  of  FIG. 3 , a valve  112  comprises a valve body  114 , a valve seat  116  and a valve element  118 , such as a butterfly disc, plug or the like. An orifice  120  is provided through the valve element. Thus, when the valve  112  is open evacuation can occur quickly, and when the valve  112  is closed it can occur more slowly. 
     Turning now to  FIG. 4 , while highly concentration of the sterilizing vapor is helpful in achieving sterilization efficiency and efficacy, getting the vapor into contact with the items to be sterilized is also a concern. Typically, the low pressures (0.5 torr to 10.0 torr) inside of a chamber  12  promotes quick diffusion of the sterilant vapor to all areas therein. 
       FIG. 4  illustrates a sterilization system  60  comprising a chamber  62  having a vaporizer  64 , vacuum pump  66  and vent  68  connected thereto. Preferably, an elongated, temperature controlled diffusion path  70  as previously described connects the vaporizer  64  to the chamber  62 . A throttle valve  72  and pressure gauge  74  are provided at the pump  66 . 
     Articles  76  to be sterilized are placed into trays or containers  78 . Two types of packaging are commonly used in preparing articles  76  for sterilization. In one, the articles  76  are placed into a tray having a plurality of openings therein, and the tray is then wrapped with a material such as CSR wrap which passes sterilizing gases and blocks contaminating microorganisms. Such a tray is described in the Wu, U.S. Pat. No. 6,379,631, incorporated herein by reference. An alternative package comprises a sealable container with several ports, preferably on top and bottom surfaces thereof, with each of the ports covered by a semi-permeable membrane which passes sterilizing gases and blocks admission of contaminating microorganisms. Such a container is described in Nichols U.S. Pat. No. 4,704,254, incorporated herein by reference. The first type of packaging is typically called a “tray” and the second a “container.” However, the term “container” as used herein is meant to refer to any container, packaging or enclosure suitable for containing articles to be sterilized in a chemical vapor environment. 
     The pump  66  connects to the chamber  62  via an exhaust manifold  80 . The manifold  80  comprises one or more shelves  82  for supporting and receiving one or more containers  78  and which connect fluidly through the throttle valve  72  to the pump  66 . An opening, or preferably a plurality of openings  84  on the upper surfaces of the shelves  82  allow the pump  66  to draw atmosphere within the chamber  62  through the openings  84 , through the manifold  80  and out through the pump  66 . 
     The containers  78  preferably have openings  86  on a lower surface  88  thereon and additional openings  90  on at least one other surface. When the containers  78  are placed on the shelves  82  atmosphere being exhausted by the pump  66  is drawn in part through the openings  90  into the container  78 , through the container into contact with the article or articles  76  therein and then out through the openings  86  into the manifold  80  through the openings  84  therein. When the atmosphere being so exhausted contains a sterilizing gas it enhances its penetration into the containers  78  and into contact with the articles  76  therein. 
     Sterilizing gases are so exhausted during the previously described cycle as the sterilant solution is vaporizing and immediately before the second admission of hydrogen peroxide. Such a cycle can also further provide a pump-down after some period of diffusion. After admitting the sterilant vapor the chamber  62  pressure rises slightly due to the presence of additional gas therein, typically from about 0.5 torr to about 10 torr. Higher pressure can also be achieved with higher load and chamber temperatures. 
     Turning also to  FIGS. 5 and 6 , an alternative design (in which like part numbers to those of the design of  FIG. 4  are designated with a “b” appended thereto) replaces the manifold  80  of the design of  FIG. 4  with a simple port  92 . The port  92  is covered by a support  94  for the container  78 , the support  94  having a plurality of openings  96  therethrough so that the chamber  62   b  is in fluid communication with the pump  66   b  through the container  78 , the support  94  and the port  92 . The support  94  can be removable. 
     Turning also to  FIGS. 7 and 8  (in which like part numbers to those of the designs of  FIGS. 4 to 6  are designated with a “c” appended thereto) shows a support  100  resting on a surface  102  in the chamber  62   c  through which penetrates the port  92   c . The support  100  surrounds the port  92   c . Thus, most or all of the atmosphere being exhausted by the pump  66   c  passes through the container  78  into a space  104  formed between the container  78 , the support  100  and the surface  102  and then onto the pump  66   c  through the port  92   c.    
     While a connection to a container solely via the exhaust lends a certain simplicity to the design, such a container may have alternative connections. Turning also now to  FIG. 9 , a container  200  has one or more upper openings  202  and one or more lower openings  204 . The container fits within a chamber  206  via a door  207 . The chamber  206  has an inlet manifold  208  connected to the vaporizer (not shown in  FIG. 9 ) and an outlet manifold  210  connected to the vacuum pump (not shown in  FIG. 9 ). Preferably, the upper and lower openings  202  and  204  are filtered in some fashion as herein described before so as to allow ingress and egress of sterilizing gases while preventing the ingress of contaminating microorganisms. Multiple containers  200  could be located between the inlet and outlet manifolds  208  and  210 , each container  200  being individually sealed. 
       FIG. 10  illustrates a further container  220  in the chamber  206 , the container  220  further having a manifold  222  connected to lower openings  224  (or alternatively to upper openings  226 ). A lumen device  228 , such as an endoscope, having a lumen  230  therethrough, the lumen  230  having a first end  232  and a second end  234 , connects to the manifold  222  so that the lumen first end  232  is fluidly connected to the manifold and the lumen second end  234  fluidly communicates with the manifold  222  through the lumen  230 . The manifold  222  is preferably designed so as to fluidly connect to a remainder  236  of the container  220  solely though the lumen  230 , thus forcing flow of sterilizing gases through the lumen  230 . In a preferred use, a vacuum is drawn upon the container  220  and then sterilizing gases admitted thereto through the inlet manifold  208 . During this step, or thereafter, some portion of the gases are exhausted through the exhaust manifold  210  to flow sterilizing gases into the lumen  230 . Preferably, a number of such lumen devices  228  can similarly connect to the manifold  222 . Preferably, the connection thereto is normally closed until the device  228  is connected thereto so as to prevent formation of a bypass route for the gases to avoid passing through the lumen  230 . For faster initial pump-down rates a bypass valve (not shown) could be provided between the manifold  222  and the remainder of the container  236 , which valve would open only under a predetermined pressure difference. 
       FIG. 11  illustrates a container  250  which can be disposed within a sterilization chamber  252  via a door  254 . A single manifold  256  in the chamber  252  interfaces with the container  250  via an opening  258  in the manifold  256  and an opening  260  in the container  250  which are adjacent one another. No physical attachment between the container  250  and manifold  256  need occur. In this embodiment, the container  250  rests atop the manifold  256  with the openings  258  and  260  in registry. The opening  260  could be provided in sidewalls or top walls of the container  250  with the opening  258  being moved so as to register therewith. For ease of use, the container  250  and manifold  256  would preferably merely abut one another. 
     A source of sterilant  262 , such as a vaporizer, connects the manifold  256  as does an exhaust pump  264 , such as a vacuum pump. Each of the source  262  and the pump  264  can be isolated from the manifold via valves  266  and  268  respectively. While sterilant flows through the manifold  256  to the container  250 , the valve  268  isolates the pump  264  from the manifold  256  and while the pump  264  is working, the valve  266  would isolate the vaporizer  262  from the manifold. Additional openings  270  could be provided in the container  250  to allow diffusion of sterilant out of the container  250  into the chamber  252 . 
     The invention has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Technology Category: 1