Abstract:
A device and system is disclosed for sterilizing objects, commonly dental, medical, or veterinary instruments, by enhancing rapid hot air diffusion into an instrument container by means of a sliding cover overlaying an opening in the bottom of the instrument container when in the closed position and sliding horizontally to reveal the opening in the open position, allowing rapidly flowing hot air into the container for medical article sterilization. The sliding cover is moved to the open position just prior to the sterilization process by a mechanical means incorporated into the sterilizer with the sliding cover remaining in the open position through the completion of the sterilization process. Once the sterilization cycle is complete, the mechanical means is reversed, closing, sealing, and locking the sliding cover in place over the opening before the instrument container is removed from the sterilizer, ensuring continued medical instrumentation sterility inside the container.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This is a continuation in part of U.S. patent application Ser. No. 61/468,623 filed Mar. 29, 2011. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates to an apparatus and method for sterilization of items. These may be instruments used in medical, dental, veterinary, or other markets, or for the sterilization of other items. There is a need for a device to quickly and efficaciously sterilize objects, such as medical instruments in hospitals, clinics, dental facilities, veterinary, and laboratory facilities. 
         [0003]    Currently, steam sterilization is used in hospitals and clinics to sterilize the majority of instruments or other devices. Steam sterilization is also utilized in time of critical instrument need by modifying standard operating protocols and “flashing” steam to the unwrapped instrument or device. The reduced time-temperature profiles of such a technique are often not evaluated for sterilization assurance and have resulted in instruments and devices remaining microbiologically contaminated after treatment. “Flash sterilization” is not a recommended procedure, but in times of critical instrument or device need, it is the only relatively quick method of sterilization available to the medical facility. 
         [0004]    U.S. Pat. No. 4,923,681 issued May 8, 1990 to Cox et al. discloses a High Velocity Hot Air Sterilization Device with Controller. High velocity hot air sterilization technology has the potential to meet the sterilization needs of the medical facility as both a standard and expeditious sterilization technology for heat-resistant instruments or devices. However, the original design of the unit limited its usefulness due to its inability to accommodate closed instrument containers that could assure internal conditions for instrument sterilization and yet maintain the sterility of those instruments from environmental microbial contamination once the instrument container was removed from the sterilizer chamber. 
         [0005]    The present invention serves to remedy these inadequacies by incorporating described design features into a high velocity hot air sterilization device or other similar devices that are integrated with novel design features of the described instrument container. 
         [0006]    These designs allow the introduction of high velocity air into the container under conditions that lead to instrument or device sterilization, yet provide the physical containment necessary to protect sterilized instruments from external environmental microbial contamination once the container has been removed from the sterilizer. 
       DESCRIPTION OF PRIOR ART 
       [0007]    U.S. Pat. No. 4,923,681 issued May 8, 1990 to Cox et al. discloses a High Velocity Hot Air Sterilization Device with Controller. This device was designed and marketed for use in the dental market to rapidly sterilize small instruments without instrument corrosion. The unit as designed was small and built to accommodate a limited volume of the smaller dental instruments requiring sterilization. With the Cox High Velocity Hot Air Sterilization Device wrapped or unwrapped instruments are placed into a wire mesh, open basket and held for pre-designated times at 375° F. as previously prescribed by the U.S. Food and Drug Administration approval (K8726643A and K881371) for (1) unwrapped instruments, (2) air rotor hand pieces or for instruments with air or water tubing, and (3) wrapped instruments. Upon completion of the sterilization cycle the basket containing the instruments is removed from the sterilizer. Unless covered with a sterile covering, unwrapped instruments are immediately subjected to potential external microbial contamination. For the dental client, this practice is acceptable since sterilization of dental instruments has placed emphasis on obtaining complete kill of microorganisms emanating from previous patients with no concern regarding post-sterilization contamination from microbial contaminants having environmental origins. 
         [0008]    For the healthcare and veterinary client, sterilized instruments and devices must retain their sterility prior to their entry into the sterile surgical field and as such, cannot be subject to post-sterilization microbial contamination. In healthcare and veterinary care, protection of sterilized instruments is maintained by wrapping instruments in sterile wrap and subsequently subjecting them to the sterilizing agent (i.e., wet steam heat, dry heat, radiation, or chemical agent) or by placing the instrument(s) in a closed container designed to allow that particular sterilizing agent to migrate through and to have contact with the contained instruments, thus achieving instrument sterilization. 
         [0009]    Although wrapping instruments had been a primary mechanism of maintaining instrument sterilization using wet steam heat, static dry heat, radiation, and chemical agents in the past, emphasis has shifted to the use of closed containers for sterilizing larger quantities of instruments and providing subsequent protection from environmental microbial contaminants. With the increased use in healthcare of closed container systems, the use of closed containers in dental clinics has also become the preferred way to protect and store sterilized dental instruments. 
         [0010]    Closed containers allowing migration of the sterilizing agent into the container for instrument sterilization have been developed to accommodate specific sterilizing agents. The design of the container and/or its portal design must be congruent with the attributes of the sterilizing agent and not interfere with the influx of the sterilizing agent. Accordingly the design must assure in some manner, the protection of the sterilized instruments from microbial agent contamination from the point of exiting the sterilizer until the container is opened for instrument use. 
         [0011]    Closed containers have been designed to incorporate top and bottom perforations protected by a microbial filtering material that is permeable to gas or vapor sterilants, but is impermeable to microorganisms. These perforations may be static, remaining continuously open and filtered. An example of such a container is contained in U.S. Pat. No. 4,551,311 issued Nov. 5, 1985 to Lorenz and entitled “Sterilizer Container.” 
         [0012]    Another design incorporates open side vents (U.S. Patent Application Publication No.: US 2003/0211023 Al; Su-Syin Wu and Charles Howlett; “Instrument Sterilization Container Having Improved Diffusion”) to allow gas or vapor sterilants into the container. Protection from microbial contaminants is accomplished through the incorporation of internal or external microbial filters by wrapping the instruments or wrapping the entire container. 
         [0013]    The container may also be of a non-static design, providing an automatic opening and shutting mechanism. For steam sterilization the pressure differential between the inside and outside of the container triggers an automatic opening and closing of a pressure-sensitive valve (U.S. Pat. No. 5,352,416 issued Oct. 4, 1994 to Wagner and entitled “Valve Arrangement for a Sterilization Container”). 
         [0014]    Rapid heat transfer sterilizers employ rapidly flowing hot air over the surface of an article to affect microbial kill. Hot air influx into the container at a sufficient rate is therefore necessitated to achieve sterilization in the prescribed time-temperature profile previously approved by the U.S. Food and Drug Administration for the Cox unit. Any barrier to that necessitated rate of airflow will significantly impact sterilization conditions. Our research has demonstrated that container perforation coupled with fabric filtration will disturb hot air influx into the container and to the instrument and has significant impact on the conditions necessary to achieve reliable instrument sterilization. Existing instrument containers that employ perforations in the top, sides, and/or bottom of the container also require fabric filtration to mitigate microbial contaminants and thus, prohibit the necessary conditions required for instrument sterilization by high velocity dry heat. Existing instrument containers that utilize pressure valves were specifically designed for pressurized wet steam sterilizers and do not function under the non-pressurized treatment conditions employed in high velocity dry heat sterilization. 
         [0015]    The need exists for a high velocity hot air sterilization device integrated with a novel, closed container system that can provide a mechanism to allow for the access of sufficiently flowing high velocity hot air to instruments/devices for their sterilization and also allow for the container to subsequently protect the sterilized instruments from microbial contaminants having environmental origin once the container has been removed from the sterilizer. 
       SUMMARY OF THE INVENTION 
       [0016]    The present invention provides a rapid transfer dry-heat sterilization system for sterilizing medical, dental, or veterinary instruments or other devices or for other purposes. It is the object of the invention to expand the utilization of the sterilization device as embodied in the invention of Cox et al. More specifically the invention provides: (1) the ability to sterilize trays of instruments and devices within a closed container having the design to allow high velocity dry heat air to enter the container and sterilize contained instruments under the sterilization temperature and time parameters prescribed by the U.S. Food and Drug Administration and (2) the ability to subsequently protect the sterilized instruments from microbial contaminants of ambient environmental origin upon removal of the container from the sterilizer. 
         [0017]    Thus, the present invention relates to a covered sterilization container system comprising a lid, sidewalls, and bottom. The lid and sidewalls form an enclosure. The base is comprised of a cut-out portion (1) that is covered by a sliding sealable cover or cap when the container is outside the confines of the high velocity hot air sterilizer, (2) that is uncovered during or subsequent to the container&#39;s entry into the sterilizer and during the sterilization cycle, and (3) that is covered and sealed during or prior to the exit of the container from the sterilizer. The present invention also provides integrated sterilizer-container mechanisms to move the sliding cover or cap from closed to open to closed positions during or subsequent to the entry into and during or prior to exit from the sterilizer. Furthermore, the invention also provides locking and unlocking mechanisms for the sliding cover or cap to ensure its placement across the open portion of the container base so that the instruments and devices in the container maintain sterility after the sterilization process. In addition, the invention provides mechanisms for a tight seal of the sliding cover or cap against the container base when the sliding cover or cap is in the closed position. Additionally, the invention provides for (1) a lid of the container to allow hot air diffusion out of the container, but microbiologically filtered to allow for enhanced cooling of the instruments after the sterilization process and (2) a lid having internal baffling to enhance hot air circulation throughout the container during the sterilization cycle. 
         [0018]    Preferably, the container and all its subparts are comprised of materials able to withstand the rigors presented by the temperatures utilized in high velocity hot air sterilization (375 degrees F. or higher). Preferably, these materials include primarily stainless steel, high temperature resistant thermoplastic and thermosetting polymers, ceramics, silicone, and nylon fabric plastics. 
         [0019]    Preferably, the container is positioned into the sterilizer by its placement onto a sliding tray, which guides the container into and out of the sterilizer and assures the open-close mechanisms for the sliding cover or cap are properly aligned and positioned. 
         [0020]    Preferably, the container base is constructed with an open bottom portion to allow the high velocity hot air into the container from the sterilizer when the sliding cover or cap is in the open position. 
         [0021]    Preferably, over the open portion of the container is a series of baffles that direct the high velocity air from the sterilizer to all parts of the container. 
         [0022]    Preferably, the open portion of the container bottom is uncovered by means of a sliding cover or cap which is pushed or pulled away from the opening during or subsequent to the container&#39;s entry into the sterilizer and which is re-covered by the sliding cover or cap when pushed or pulled back to the closed position prior to or during the removal of the container from the sterilizer. The sliding cover or cap may be mounted either internally or externally to the bottom of the instrument container. 
         [0023]    Preferably, the sliding cover or cap is moved to the open or closed position by the use of a fixed or movable mechanism attached to the sterilizer base and which engages with the sliding cover or cap on a instrument container or sliding covers or caps on multiple instrument containers on single or multiple levels having one or more air plenums within the sterilizer. 
         [0024]    Preferably, a sliding cover or cap is guided by means of two parallel rails allowing the sliding cover or cap to transverse from the closed position at entry or subsequent to entry into the sterilizer to the fully open position during the sterilization cycle, and back to the closed position prior to or upon the container&#39;s exit from the sterilizer. Stops at either end of the rails ensure the sliding cover or cap remains between the rails and assure the correct positioning of the sliding cover or cap. Depending on the mounting location of the sliding cover or cap, these rails may be attached internally or externally to the bottom of the instrument container. 
         [0025]    Preferably, the sliding cover or cap is constructed from a durable heat-resistant metal, plastic, or ceramic material having a silicone or other heat resistant gasket at the container-cover/cap interface to seal the sliding cover or cap against the surface of the base. Preferably, to further assure a tight seal over the opening of the container base, the internal configuration of each rail is sloped so as to tighten the gasket against base when the sliding cover or cap is in the closed and locked position. 
         [0026]    Preferably, to further assure that the sliding cover and cap remains in the closed position once the sterilizer container is removed from the sterilizer, a locking mechanism or holding mechanism is engaged. 
         [0027]    Preferably, a sliding cover locking or holding mechanism is automatically disengaged during the entry or subsequent to the entry of the container into the sterilizer to allow the sliding cover or cap to move into the open position prior to the sterilization process and is re-engaged once the sliding cover or cap is re-located into the closed position before the container is removed from the sterilizer. 
         [0028]    Preferably the sterilizer creates a laminar airflow curtain at the entrance to the sterilizer chamber in a sufficient volume and speed of airflow to preclude entry of microbial contaminants external to the sterilizer during and subsequent to the sterilization process when instrument containers are being withdrawn from the sterilizer chamber. 
         [0029]    Preferably, the container has a lid opening that is centered and onto which is placed a spunbond or nonwoven nylon microbial filter sealed in a rigid housing and sealed against the lid to allow heat to escape and instruments to cool after the sterilization process. 
         [0030]    Preferably, the container has a lid that contains a baffled internal surface to enhance hot air circulation throughout the container during the sterilization cycle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    In describing the invention, reference will be made to the accompanying drawings in which: 
           [0032]      FIGS. 1A ,  1 B, and  1 C are perspective views of the instrument container and inverted lid; 
           [0033]      FIGS. 2A and 2B  are external views of the top of the instrument container lid having a microbial filter and bottom of the instrument container base having an external slide cap in an open position; 
           [0034]      FIGS. 3A and 3B  are cross-sectional side elevation views of the instrument container with external slide cap and slide rails situated in both closed and open slide cap positions within the high velocity hot air sterilization device; 
           [0035]      FIGS. 4A ,  4 B, and  4 C are cross-sectional views of the external slider rail, slide cap, and gasket seal in both open and closed positions; 
           [0036]      FIGS. 5A and 5B  are cross-sectional views of the external slide cap locking mechanism; 
           [0037]      FIGS. 6A ,  6 B,  6 C, and  6 D are internal and external views of the bottom of the instrument container exhibiting an internal sliding cover in both open and closed positions; 
           [0038]      FIGS. 7A and 7B  are cross-sectional side elevation views of the instrument container with internal sliding cover and slide rails situated in both closed and open sliding cover positions within the high velocity hot air sterilization device; and 
           [0039]      FIGS. 8A and 8B  are isometric and front elevation views of a two-container, internal sliding cover configuration within a sterilizer depicting the push-pull engagement bar with the containers&#39; push-pull bars. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0040]    The present invention provides a sterilization system that utilizes high velocity dry air heat to sterilize medical, veterinary, and dental instruments and devices that are situated in a novel container which allows the high velocity hot air to penetrate and diffuse within that container and which allows such sterilized instruments and devices to remain protected from environmental contaminants upon removal of the container from the sterilizer. 
         [0041]    The present invention embodies two distinct mechanisms that can be employed to open and close instrument containers. One embodiment describes a mechanism in which the sterilizer has a fixed engagement bar that physically engages a sliding cap on the container, pushing it to reveal an opening in the container&#39;s base during container entry and pulling it back across the opening during the container&#39;s exit from the sterilizer. Another embodiment is described in which a pulley push-pull mechanism operated by the door latching and locking mechanism pulls the sliding cover to reveal an opening in the container&#39;s base and pushes the sliding cover back across the opening to a closed position once the instrument container has been loaded into the sterilizer. 
         [0042]    The present invention is also envisioned applicable for other sterilization systems that may employ steam or sterilant gas or vapor, or heat to inactivate or kill microorganisms by providing direct access of the sterilizing agent to a medical instrument or article during a sterilization process and by protecting the sterilized instruments or articles from environmental contaminants once the container is removed from the sterilizer. 
         [0043]    The present invention may also be envisioned to bring air into the instrument container through the top (lid) or sides of the container. 
         [0044]    The preferred and described embodiment of the present invention is described below. 
         [0045]      FIG. 1A  is a perspective view of the preferred rectangular sterilization container  15 . The sterilization container  15  is typically rectangular in shape with solid sidewalls  1  and end walls  2  and having a base  3  on which reside support feet  4  or perpendicular base extensions on its exterior. The solid base  3  contains an air entry portal  5  over which are baffles  6  that serve to deflect forced high-velocity hot air from the sterilizer into all portions of the container  15 . 
         [0046]      FIGS. 1B and 2A  are views of the container lid  7 . The lid  7  (shown inverted) has solid sidewalls  8  and end walls  9 .  FIGS. 1B and 2A  depict the container lid top  10 , which is solid with a cut out portion  11  containing a nested and sealed thermal-resistant spunbond or nonwoven nylon, removable microbial filter  12  which is designed to assist in the cooling of the interior of the container  15  after the sterilization process. During sterilization the lid  7  is affixed to the container  15  and remains affixed until such time the sterile instruments are required. 
         [0047]      FIG. 1C  is a perspective view (shown inverted) of the container lid  7  containing a solid baffle  28  to deflect hot air entering the container  15  from the air entry portal  5  during the sterilization process to aid in its diffusion throughout the container  15 . 
         [0048]      FIGS. 2B ,  3 ,  4 , and  5  depict an embodiment in which an instrument container  15  has an external slider cap  20  to which is inserted a fixed engagement bar  31  that is attached to the sterilizer  40 . Entry of the instrument container  15  into the sterilizer  40  results in the external slider cap  20  remaining stationary while the container  15  is manually pushed to the rear of the sterilizer  40 , thus uncovering the air entry portal  5  and allowing rapidly flowing hot air to enter the container  15  and sterilize instruments. Upon completion of the sterilization process the container  15  is manually pulled to the front of the sterilizer  15 , closing and sealing the external slider cap  20  across the air entry portal  5  to preclude microorganisms from contaminating the sterilized instruments. The closed instrument container  15  can now be removed from the sterilizer  40  by lifting up the instrument container  15 , thus disengaging the fixed engagement bar  31  from the slider cap&#39;s  20  insert well  22 . 
         [0049]      FIG. 2B  is a view of the underside of the container base  3  having parallel externally-mounted slide rails  18  along the length of the container base  3  on which rides a slider cap  20  containing an external insert well  22  for the slider cap engagement bar  31  ( FIGS. 3A and 3B ). The slider cap  20  covers the air entry portal  5  when in the closed position ( FIG. 3A and 4B ). The underside of the base  3  contains four container support feet  4  that protect the slider cap  20  and parallel mounted slide rails  18  that run along the length of the container base  3 . 
         [0050]      FIG. 3  depicts a cross-sectional side elevation view of a preferred embodiment of the instrument container  15  and lid  7  with slider cap  20  and slide rails  18  with rail end caps  19  situated in both closed  29  and open  30  slider cap positions within the high-velocity hot air sterilization device  40 . The instrument container  15  holds a basket  14  or alternative instrument holding device which contains the instruments to be sterilized. The basket  14  sits on a perforated stainless steel floor covering  16 , which provides support for the basket  14  over the opening  5  in the container floor and the air baffles  6 . The container  15  is placed into the sterilizer  40  by means of a holding tray  17 , which provides guidance and positioning of the container  15  as it is pushed into the sterilizer  40 . Positioning and guidance are required to properly seat the slider cap engagement bar  31  into the bar insert well  22  of the slider cap  20 . Upon pushing the container  15  into the sterilizer chamber the sliding cap  20  is retained at the front of the sterilizer  40  while the container  15  is pushed to the rear of the sterilizer  40  thus allowing the slider cap  20  to slide away from the air entry portal  5  along the parallel slide rails  18  and allowing high velocity hot air to enter the container  15  from the bottom of the sterilizer  40 . Upon completion of the sterilization process the instrument container  15  is pulled from the sterilizer  40  and the process is reversed, sliding the slider cap  20  to cover the air entry portal  5 . The sterilized container  15  is removed from the sterilizer  40  disengaging the coupling between the slider cap  20  and slider cap engagement bar  31 . Subsequent to the sterilization process when the sterilizer door  41  is opened and instrument containers  15  are withdrawn from the sterilizer  40 , the sterilizer  40  continues to generate a laminar airflow curtain at the entrance to the sterilizer  40  chamber that is sufficient in airflow volume and speed to preclude entry into the sterilizer of environmental microbial contaminants. Therefore the laminar airflow curtain also precludes potential microbial entry into the instrument container  15  as the slider cap  20  is pulled to the closed position during the container&#39;s  15  removal. At any time during container  15  removal, the leading open edge of the air entry portal  5  always remains near the middle of the sterilizer  40  chamber, thus assuring no microbial contaminants from the outside environment can enter the instrument container  15  during its removal. To assist in the release of hot air retained inside the instrument container  15  after the sterilization process is complete, a removable spunbond or nonwoven nylon microbial filter  12  is contained in the lid  7 , sealed in a rigid housing  13  over the opening  11 . 
         [0051]      FIGS. 4A and 4B  depict cross-sectional views of the slider rail  18  and slider cap  20  with attached gasket  27  in both open  30  and closed  29  positions of the air entry portal  5  and air baffle  6  in the instrument container  15 . In the open position  30  the slider cap  20  with attached gasket  27  rides loosely on the slider rail  18  with little or no contact to the gasket  27  against bottom of the instrument container  15 . In this position the slider cap rests near or touching the front rail end cap  19 A. In the closed position  29  the slider cap  20  is pulled back into its position immediately under the air entry portal  5 . The slider cap  20  with attached gasket  27  is wedged tightly against the external bottom of the container base  3  immediately surrounding the perimeter of the air entry portal  5  by providing a slope and plateau on the back half of the interior bottoms of the parallel slide rails  18  causing the slider cap  20  to rise slightly and compress the attached gasket  27  tightly against the external bottom of the container base  3 . The rear rail end caps  19 B prevent the slider cap  20  from going beyond the correct sealable position. A rear view  32  is depicted in  FIG. 4C  of the slider rail  18 , slider cap  20  with attached gasket  27 , and rail end caps  19  in the closed  29  position under the air entry portal  5  and air baffle  6  in the instrument container  15 . The gasket  27  preferably is composed of a high-heat resistant material such as silicone or other comparable material that can be successfully compressed against the bottom of the container base  3 . The slider cap  20 , slide rails  18 , and rail end caps  19  are preferably composed of a hard, high-heat resistant plastic material or other material as found suitable for the application. 
         [0052]      FIGS. 5A and 5B  depict a cross-sectional top and side elevation views, respectively, of a preferred embodiment of a slider cap locking mechanism to retain the slider cap  20  in its closed position. Channeled internally into the slider cap  20  are two cables  23  attached to a spring  26  -loaded push bar  21  on one end and on the other end to two spring-loaded pins  24  which are actively engaged into holding slots  25  located internally on each slide rail  18  at the back end of the slide rail  18  and in a position to lock the slider cap  20  in place directly centered beneath the air entry portal  5  in the instrument container  15 . Upon entering the sterilizer  40 , the instrument container  15  is lowered onto the holding tray  17  and positioned by inserting the slider cap engagement bar  31  into the bar insert well  22  of the slider cap  20 . By pushing the instrument container  15  toward the back of the sterilizer  40  the slider cap  20  is retained in place, pushing the slider cap engagement bar  31  against the spring  26 -loaded push bar  21  toward the front of the bar insert well  22  thus tightening the two cables  23  attached the two spring-loaded pins  24  and pulling them out of their respective holding slots  25  in the slide rails  18 . The slider cap  20  is then free to move to the front portion of the container  15  in its open position. At the completion of the sterilization cycle, the instrument container  15  is pulled out of the sterilizer  40 , thereby forcing the slide cap engagement bar  31  against the back portion of bar insert well  22  and releasing the spring-loaded  26  push bar  21  to relax the two cables  23  and cause the two spring-loaded pins  24  to re-engage into their respective holding slots  25 , locking the slide cap  20  back in its closed position. Although the preferred embodiment is the use of spring-loaded pins and push bar, it is envisioned that other locking mechanisms may also serve to lock and unlock the slider cap  20  which may or may not include springs or cables and may include the use of dense memory foams or metal clips. 
         [0053]      FIGS. 6 ,  7 , and  8  depict a second embodiment in which an instrument container  15  has an internal sliding cover  50  which is moved from a closed position over the air entry portal  5  by a pulley  44  pull-push mechanism connected to the sterilizer door  41  latching and locking apparatus. Upon positioning the container  15  on the holding tray  17  and insertion into the sterilizer  40 , a cable  45  is pulled forward via a pulley  44  when the door handle  42  is turned to its closed and locked position, pulling an internal sliding cover  50  and opening the air entry portal  5 . The mechanism is reversed upon completion of the sterilization cycle when the sterilizer door  41  is unlocked and the latch is positioned to the open position, pushing the cable  45  and thus the sliding cover  50  into the closed position over the air entry portal  5 . The closing of the sliding cover  50  is aided by a spring-loaded piston  53  or similar device located on the external bottom of the container base  3 . The spring-loaded piston  53  also serves to lock or hold the sliding cover  50  in place over the air entry portal  5 . 
         [0054]      FIGS. 6A and 6B  and  FIG. 6C  and D depict the internal sliding cover  50  configuration on the inside and outside, respectively, of the container base  3  in both the closed ( FIGS. 6A  and C) and open positions ( FIGS. 6B  and D). Two parallel sliding cover rails  52  position the sliding cover  50  within the container  15  and allow it to slide freely from the closed position covering the air entry portal  5  to the open position uncovering the air entry portal  5 . Attached to the bottom of the sliding cover  50  is a sliding cover push-pull bar  51  extending downward from the sliding cover  50  to engage a push-pull engagement bar  49  that pushes the sliding cover  50  to the open position uncovering the air entry portal  5  when the sterilizer door  41  is latched and locked ( FIG. 7 ). Parallel external rail guides  55  located externally on the container base  3  assist in the positioning of the push-pull engagement bar  49  during the uncovering and covering of the air entry portal  5 . A push-pull compression spring piston  53  is used to assist in the return of sliding cover  50  to the closed position covering the air entry portal  5  and to hold the sliding cover  50  in place to prevent microbial contamination of sterilized instruments during storage. The compression end of a push-pull spring piston  53  is externally attached to the instrument container base  3  and the distal piston end is attached to sliding cover push-pull bar  51 . The push-pull spring piston  53  is in the extended mode when the sliding cover  50  is covers the air entry portal  5  ( FIG. 6A and 6C ) and is compressed when the sliding cover  50  has been pushed to the open position ( FIG. 6B and 6D ), uncovering the air entry portal  5  to allow hot rapidly flowing air entry into the instrument container  15 . Although the preferred embodiment is the use of a push-pull compression spring or rod, or combination thereof, it is envisioned that other similarly functional devices or mechanisms may also be employed. Alternative means to move the sliding cover  50  or slider cap  20  are also envisioned using other mechanical means with (e.g., electromagnetic means or servo motors) with or without electrical or hydraulic/pneumatic assist and with or without pulley assist (e.g., levers or other mechanical means). 
         [0055]      FIG. 7  depicts a cross-sectional side elevation view of a preferred embodiment of the instrument container  15  incorporating an internal sliding cover  50 .  FIG. 7A  depicts the sliding cover  50  in the closed position over the air entry portal  5  and  FIG. 7B  depicts the sliding cover  50  in the open position aside the air entry portal  5 . The sliding mechanism is activated once the container  15  has been placed on the holding tray  17 , inserted completely into the sterilizer  40 , and during the closing and locking the sterilizer door  41 . Rotating the sterilizer door latch handle  42  engages the sterilizer door latch  43  to the locking position, simultaneously rotating the cable pulley  44  to which is attached a cable  45 . Pulled around the cable pulley  44 , the cable  45  pulls the push-pull engagement bar  49  forward by way of a push-pull rod  46  intermediate. Thus engaged, the sliding cover push-pull bar  51  pushes the sliding cover  50 , positioned by the parallel external guide rails  55 , to uncover the air entry portal  5  to the backstop  47 . The push-pull engagement bar  49  is held in position and kept on track by way of push-pull engagement bar guide  48 . 
         [0056]    As the push-pull engagement bar  49  pushes the sliding cover push-pull bar  51 , the push-pull spring piston  53  compresses against the internal (or external) compression spring  54 . The push-pull spring piston  53  is held in this position until the sterilizer door latch  43  is released and the sterilizer door latch handle  42  is counter-rotated causing the cable pulley  44  to unwind the cable  45  and release the tension to the push-pull engagement bar  49 . As the tension is released, the pressure against the push-pull spring piston  53  is subsequently lessened and the push-pull spring piston  53  pushes the sliding cover push-pull bar  51  and sliding cover  50  back to the closed position where the remaining tension in the push-pull spring piston  53  holds the sliding cover  50  in place over the air entry portal  5 . 
         [0057]      FIG. 8A  and  FIG. 8B  represent the spatial configuration of the push-pull engagement bar  49  within the sterilizer  40  in relationship to an instrument container or containers  15 , holding tray  17 , and the sliding cover push-pull bar  51 .  FIG. 8  depicts a sterilizer  40  holding two instrument containers  15  side-by-side with the push-pull engagement bar  49  engaging both containers  15  and pulled/pushed by a single cable  46  attached to the cable pulley  44 . The push-pull engagement bar  49  is positioned and guided by parallel push-pull engagement bar guides  48  attached in the sterilizer  40  floor. This configuration allows multiple containers  15  to be handled by a single push-pull engagement bar  49  whether on a single plane as depicted and/or on multiple tiers or levels.