CA1162021A - Sterilized storage container - Google Patents

Abstract

STERILIZED STORAGE CONTAINER
Abstract A container is provided having a base and a lid with the base being formed relatively flat but with the center portion of the base raised so that condensation within the container will flow to the edges and out of the container when the lid is not in a closed position. The lid is held partially open by an actuator pin connected to an expandable chamber which will expand in response to the pressure drop at the end of the sterilizing cycle to withdraw the pin and allow the lid to close onto the base. In this way, the container is closed after the contents have been sterilized and after any condensation within the container has been allowed to drain, but before the container is exposed to unsterile environment. A valve controlling the flow of steam into the expandable chamber closes when subjected to the high temperature steam, thus capturing the steam which eventually expands to cause withdrawal of the pin. The container lid and base together with a gasket permit steam to be withdrawn from the container but prevent air flow into the container once the lid is closed. A vacuum created within the container at the end of the sterilizing cycle holds the container lid in place.
In another arrangement, an expandable chamber is em-ployed to cause the container to be sealed at a predetermined pressure after the container has been subjected to a final vacuum in an autoclave cycle but before the container is removed from the autoclave. The lid is first held open by one end of a pivotally mounted lever. A temperature triggered, pressure re-sponsive expandable chamber is employed to pivot the lever, withdrawing the end of the lever which had been supporting the lid and pivoting the second end of the lever into a lid supporting position. When the pressure surrounding the expandable chamber is increased at the end of a vacuum cycle in an autoclave, the expandable chamber contracts, allowing a spring to pivot the lever and withdraw the second end of the lever from supporting the lid, thus allowing the lid to fall and seal on the base.

Description

BacXground of the Invention This invention relates to an improved system for storing items while they are being sterilized, while they are being stored awaiting use, while they are in the process of being used, and after they have been used and are awaiting res~eriliza-tion. The system is particularly useful in connection with the sterilization and stora~e of medical items,`such as surgical instruments.
The most commonly used method for sterilizing surgical instruments and other medical items i5 to place them in towels which are enclosed in a sheet and taped shut for placing in a sterilizing autoclave. Sterilizing steam applied to the interior of the autoclave penetrates the porous materials surrounding the items to be sterilized. Moisture is removed by a vacuum drying cycle within a vacuum autoclave. ~hen pressure is then returned to normal by admitting room air, unsterile air and lint from the towels are drawn into the center of the package. When the package i5 removed from the autoclave and cooled, additional room air circulates lnto the package. Thus, the items are immediately contaminated to some extent. If the package is not used im-mediately and placed in storage for a period of time, it must be returned to the autoclave for resterilization. It i~ estimated that two-thirds of the sterilization work load in many hospitals i for items that were not used within the shelf life of the pack.
This of course is an expensive and inefficient procedure which adds to the skyrocketing costs of medical treatment. Thus, a need A~ exists for a practical and reliable system for handling sterile

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items and for maintaining sterility.
German patent No. 1,642,161 of Hans Wagner, dated August 27, 1970, and ~.S.A. Patents 2,092,445; 2,997,397; and 3,468,471 disclose sterilizing containers and provide some impro~ement over 5 the towel method discussed above, but they still do not completely sterilize and seal the containers' contents in a dry essentially atmosphere free condition.
~ .S. Patent No. 4,105,407 of Roger S. Sanderson, issued August 8, 1978, and Canadian Patent No. 1,115,240 of Roger S.
10 Sanderson, issued December 29, 1981r disclose containers in which the items to be sterilized are placed within ~he con-tainer and the container is then placed within an autoclave or other sterilizer. The container is initially sufficiently open to permit the sterilizing environment to circulate within the 15 interior of the container, and the container is then sealed at an appropriate stage to maintain sterility. Such earlier con-tainer is constructed such that steam can escape or be withdrawn from the container when the pressure on the interior of the con-tainer exceeds the pressure on the exterior. Consequently, the 20 container is usually essentially dry with a vacuum type autoclave wherein a vacuum is applied to the container at the end of the steaming cycle. Also, only a slight amount of moisture remains in the container with a gravity-type autoclave for most sterilizing operations, and this moisture can be absorbed by a 25 small quantity of desiccant.
However, with loads involving a considerable mass, such as a large quantity of surgical instruments, steam must be cir-culated through the autoclave for a considerable period of time to heat the load to the necessary sterilizing temperature.
30 During this operation a conslderable amount of steam condenses on the colder metal. Although this condensate is eventually sterilized in the autoclave, i~ is desirable that the container

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in which the load is stored be as dry as possible. For that pur-pose it is preferable that the container remain open until the pressure drops at the end of a steaming phase of a sterilizing cycle, so that any condensate occurring drains from the container through the open valve.
In the German patent referred to above, the container provided has a valve in its lower wall which remains open until the temperature drops at the end of a steaming phase of a sterilizing cycle. Cons`equently, any condensate occurring drains from the container through the open valve. However, that con-tainer is not truly sealed in that unsterile air is admitted through a relief valve.

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Summary of the Invention The pxesent invention, in one aspect, resides in a method of sterilizing and storing items comprising the steps of placing the items to be s-terilized in a container, placing the container in a sterilizer with the exterior of the container in fluid communication with the interior of the container by way of access means to the interior of said container, operating the sterilizer to provide a sterilizing cycle including applying a high pressure sterilizing environ-ment to the interior and exterior of the container and then permitting the environment to be withdrawn from the sterilizer, closing said container access means, after the contents of the container have been sterilized but before the container is subjected to an insterile environment, by the use of means responsive to a substantial reduction in the pressure of the environment which occurs as the high pressure environment is withdrawn or escapes from the sterilizer, and triqgerinq the operation of said pressure responsive means by means responsive to a predetermined temperature.

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In another aspect, the present invention resides in apparatus for carrying out the above method, comprising:
a container;
means, including a sterilizer, for applying a high pressure sterilizing environment to the interior and exterior of said container;
means for permitting said environment to be withdrawn from said sterilizer;

pressure responsive means for closing the container in response to a substantial drop in the pressure of a gaseous environment applied to the container; and temperature responsive means for permitting operation of said pressure responsive means after a predetermined temperature of said environment is reached.
In one form of the present invention, an access valve is po~itioned in the lower wall of a container which remains open until the pressure drops at the end of the sterilizing cycle, which seals the container from further flow into the container.

The valve closing means includes an expandable chamber which is initially open to a sterilizing environment, such as high pres-sure steam, in an autoclave, and is then automatically closed inresponse to the steam temperature, capturing a quantity of high pressure steam within the expandable chamber. This steam causes the chamber to expand at the end of the steaming phase of the cycle when there is a significant pressure drop. The force created by the expanding chamber is employed to close the valve in the container wall.
The container lid, gasket and base are constructed such that residual steam can be withdrawn from the containex, even ; 30 after the valve is closed, when the pressure on the exterior of the csntainer is less than the pressure on the interior of the container. Moreover, when the pressure on the exterior is in-~reased, this pressure holds the ~alve in closed position and draws the lid more tightly on the base.

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In another form of the present invention, an expandable chamber-type actuator is employed to ensure ~hat the container is held open until after the end of the steaming phase to permit con~
densate to drain from the container, and the container is *hen automatically closed. More specifically, in a preferred form of this arran~ement, the container is formed with a generally flat base having no side walls, with the center of the base being raised slightly from the periphery so that condensate can flow to the edge of the container. The lid, which includes a top wall and depending sid~ walls, cooperates with the base to close the container. The lid is initially held open on one side by an element extending between the lid and the base. The element is connected to be withdrawn by the force produced by an expandable chamber, which expands as the pressure drops within the autoclave at the end of a pressure steaming phase. Thus, instead of the expandabl~ chamber closing a ~al~e, it simply releases the lid and allows it to fall int~ position. A simple, separate relief valve may be pro~ided for manually relieving the vacuum later formed in the con~ainer, to permit opening of the container.
In one ~orm of the invention, the element holding the lid open is a pin which is connected to one end of a generally disc-shaped expandable, balloon-like chamber, with the pin extending through the chamber and out the other end. The chamber i8 positioned a~ainst an upwardly extending support on the periphery of the base with the pin extending through a hole in 2~ the support to hold the lid spaced from the base. Thus, when the chamber expands, the end of the chamber which is connected to the pin moves away from the base, withdrawing the pin from its lid supporting position.

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1¦ The expandable chamber actuator is constructed so that the 2 ¦lid is allowed to close before any unsterilized air is allowed 3 ¦to enter the autoclave at the completion of its cycle. This

4 ¦provides complete sterility with either a vacuum-type autoclave, S ¦wherein a final vacuum is applied after the end of the steaming 6 ¦phase, as well as with a so-called gravity-type autoclave wherein 7 la final vacuum is not applied.
While this arrangement provides the desired result and 9 is necessary with present-day technology, a significant cost 0 saving can be made in the construction of the container, if the 1 air entering the autoclave at the end of the final vacuum in 12 a vacuum-type autoclave would be sterile. With present-day 13 autoclaves, the manner by which pressure is equalized in the 14 autoclave at the end of the final vacuum is simply to open I5 a valve which permits filtered outside room air to enter the 16 autoclave. Although the filter provides some degree of 17 sterility, it does not provide the level of sterility which is 18 desired to minimize the possibility of contamination within 19 the container. Consequently, the presently preferred approach is to cause the container to close as the autoclave pressure is 21 falling but before it reaches its lowest pressure.
22 Nevertheless, since the container lid, base and gasket are ~3 constructed to permit fluid flow out of the container even after 24 the container is closed, a very high vacuum is attained within 25 the container, particularly in a vacuum-type autoclave. Because 26 of this, it is naturally necessary that the container be 27 constructed to withstand such high vacuum~ For a variety of 28 reasons it is desirable to utilize transparent plastic to form 29 the container; and hence, it is necessary that the walls be 30 relatively thick to withstand the pressure. If in the future ~6~

1 autoclaves are provided which include a filter that essentially 2 ¦sterilizes the air which is introduced into the autoclave at the 3 ¦end of the cycle to equalize pressure, it would not be ¦necessary to close the container before the low pressure point

5 ¦during the final vacuum of an autoclave cycle; but instead,

6 ¦the container could be closed during the time the pressure is

7 ¦rising from the low point, since the air being introduced to ¦equalize pressure would be sterile. It would only be necessary 9 ¦to have the container closed before it is removed from the 10 ¦autoclave and exposed to unsterile air. Closing the container ll ¦with a lesser vacuum existing within it would lower the 12 strength requirements for the container so that the walls 13 could be made thinner. This of course would result in a 14 substantial savings of material.
Thus, in another embodiment of the invention, there is 16 provided a mechanism which holds the container open, until 17 the pressure is rising after the maximum vacuum point is 18 reached during the final vacuum phase of an autoclave cycle.
19 This mechanism employs an inflatable chamber means as an actuator to automatically control the closing of the 21 container. The expansion of the chamber is used to trigger 22 a~two-step closing operation, and the later contraction of the 23 chamber as pressure surrounding the chamber increases, causes ~4 closing of the container.
~ In a preferred arrangement of this two-step closing process, 26 a lever is pivotally mounted on the periphery of the container 27 base wlth one end of the lever extending between the lid and the 2~ base to hold initially the lid spaced from the base. A spring ~9 urges the lever into that lid holding position. As the pxess~re drops at the end of the s~eaming phase of an 3l . A

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1¦ autoclave sterilizing cycle, an in~latable chamber expands in 2 ¦the manner discussed above, and the chamber is positioned 50 3 ¦that its expansion provides a force which pivots the lever 4 ¦to withdraw the end of the lever which is initially supporting 5 ¦the lid. However, this pivoting movement simultaneously causes 6 ¦the other end of the lever, or a pin attached to it, to ~ ¦move beneath the lid so that when the lid falls from the

8 ¦support provided by the first end of the lever, it only falls

9 la small amount so that it is still retained by the other end ~0 ¦of the lever. The inflatable chamber continues to expand until 11 ¦the maximum vacuum condition is reached; however, as outside 12 ¦filtered air is then admitted to the autoclave, the increasing 13 ¦pressure surrounding this sealed inflatable chamber causes the 14 ¦inflatable chamber to once more contract. This in turn permits the lever to be once more pivoted in response to the urging 16 of the spring and withdraw the second end of the lever which 17 had been supporting the lid. Consequently, the lid falls into 18 closed posltion. The point at which the lid finally closes 19 may be easily predetermined as desired by controlling the length of the pin or second end of the lever which supports the lid.
Thus, it can be seen that the improvements described herein 22 provide versatility to insure complete sterility with present-23 day sterilizing equipment and yet are readily adaptable to improvements 24 which may occur in such equipment.
2~ Brief Description of the Drawings ':-26 ~ig. 1 is a perspective view of the container of the 27 ~earlier invention as described in ~dian Patent No. 1,115,240;
28 Fig. 2 is a cross-sectional view of the container on lines 29 2-2 of Fig. 1 illustrating the overall arrangement and the ~0 slope of the bottom wall of the container;

Fig. 3 is an exploded perspective view of the container valve and valve closing mechanism;
Fig. 4 is an enlarged cross-sectional view of the con-tainer valve and valve closing mechanism shown on the container before being actuated by the sterilizing cycle;
Fig. 5 is a cross-sectional view of the structure of Fig. 4 after the valve has been moved into sealing position on the container valve seat by the expandable chamber forming the valve closing mechanism;
Fig. 6 is a cross-sectional view of the structure of Fig. 4 showing the valve held in place by pressure on the ex-terior of the container and showing the expandable chamber in retracted position;
Fig. 7 îs a cross-sectional view of the structure of 15 Fig. 4 as it appears after the valve has been placed in position by the expandable chamber near the end of the steaming phase of a gravity autoclave, but before the valve is tightly drawn into sealing position on the container valve seat by the vacuum created in the container as it cools;
Fig. 8 is a schematic illustration of a vacuum autoclave cycle indicating the points on the pressure and temperature ~curves at which the operation of the mechanism curves;

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Fig. 9 is a sketch similar to Fig. 8 but for a gravity autoclave;
Fig. 10 is a fragmentary view showing a variation of the expandable chamber serving as a desiccant bag;
5Fig. 11 is a fragmentary view showing another variation of the container as described in C~dian Patent No. 1,115,240 wherein the lid of the container is initially held open;
Fig. 12 is a cross-sec~ional vie~ of a piston-type expandable chamber valve closing mechanism shown before the

10 chamber has expanded to seat the valve;
Fig. 13-is an elevational view of the structure of Fig. 12 showing the components after the valve has seated;
Fig. 14 is an exploded perspective view of a pxeferred form of the container of the present invention;
15Fig. 15 is an enlarged cross-sectional ~iew of the actuator mechanism shown in Fig. 14 showing the mechanism in its initial condition wherein it is supporting the lid spaced from the base of the container;
Fig. 16 i5 a view similar to that of Fig. 15 but 20 showing the expandable chamber expanded so that the pin is withdrawn and the lid is in its closed position;
Fig. 17 is a partial plan view of an embodiment of the ; invention illustrating the mechanism which does not permit the container to close until the pressure is rising after a final 25 vacuum in a sterilizing cycIe;
Fig. 18 is a cross-sectional view on lines 18-18 of Fi~. 17, showing the lid being supported h~ one end of a lever;

Fig. 19 and 20 are respectively similar to Fig. 17 and 18 with the expandable chamber expanded and the other end of the lever supporting the lid in the open position; and Figs. 21 and 22 are similar to Figs. 17 and 18 re-spectively with the inflatable chamber deflated and with the lid in a closed position.
Referring now to Figs. 1 and 2, there is shown a con-tainer 10 having a cover or lid 12 closing the open upper ~ide of a base 14 and seated on a gasket 16 extending between the base and the lid. As can be seen, the container has a generally oval or race track configuration and the lid has an upper wall 18 which slopes gradually upwardly towards the center. The purpose for the oval shape and the upwardly curving wall 18 is to pro-vide strength to the container when it is subjected to an ex-terior pressure considerably higher than the interior pressure.
The cover 12 further încludes a peripheral flange portion having a generally vertical internal wall 20 which joins at its upper end a downwardly and outwardly sloping flange 22. A tab 24 extends outwardly rom the bot~om of the flange 22 at one end of the container.
The base 14 includes an irregular but generally up-wardly extending side wall 26 formed integral with a bottom walI
2B and a downwardly extendi~g peripheral leg structure 30. The side wal~ 26 terminates at its upper end with a short vertically extending portion 32 ~hich extends into the downwardly extending ~roo~e 34 ~ormed by the inner surface of the lid flange 22 and the outer sur~ace of the lid wall 20. As can be seen from Fig.
2, the lid wall 20 fits within the upper end of the base wall 3~.
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1 portion of the side wall 26 below the upper portion 32 extends 2 outwardly to a point where the lower portion of the wall 26 3 generally aligns with or forms an extension of the exterior surface of the lid flange 220 The gasket 16 is made of flexible rubber-like material whic~
can withstand the temperatures of an autoclave operation and yer 7 provi~e an adequate seal. ,The gasket 16 includes an-inner ~
8 vertical portion which fits snugly around a groove in the wall 32 g on the upper end of the base side wall 26. The gasket 16 furt~r includes a downwardly and outwardly extending flange portion

11 which mates with the inner surface o the lid flange 22.

12 The bottom wall 28 of the base slopes generally toward a

13 valve opening 36 in the right end of the base as viewed in Fig. 2

14 The base leg 30 extends inwardly at the right end of the base to form a recess 38 in which is positioned a valve and valve closin~
16 assembly 40 which cooperates with the valve opening 36. More 17 specifically, the recess 38 is formed by a sloping leg wall 42 18 which extends in a generally cylindrical configuration about 180 19 degrees to partially enclose the valve and valve closing assembl~
38., The wall 42 is further connected to a bottom support wall g4 21 whïch extends generally perpendicular to the side wall 42 and 22 joins with a stub leg wall 46 on the periphery of the base leg.
23 A hole 41 is formed in ~he bottom wall 44 for positioning the 24 assembly 40~
As can be seen by the broken lines in Fig. 2, a second 26 container 48 may be stacked on the lower container 10 with the l-g 27 of the upper coniainer being positioned on the lid 12 in the 28 groove formed by the lid side wall 2~ and by the outer peripher~
29 of the lid upper .all 18. As seen from Fig. 1, each end of th~

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lid has a shallow recess 50 adap~ed to receive the wall portions 44 and 42 of the upper container 48. A recess 50 is formed on each end of the lid so that the user need not worry about orientation of the container 48 when it is being stacked on the container 10. Naturally more than two containers may be stacked if desired.
Referring now to Figs. 3 and 4, the valve and closing mechanism 40 may be seen to include a valve 52 which is a flexible resilient member molded of silicone rubber or other rubber-like material which can withstand steam temperatures while maintaining its resiliency. The valve includes a base 54 which when unre-strained has a genexally saucer-shaped configuration with the upper surf~ce of the base 54 forming the sealing surface against the container when the valve is closed. Attached to the central portion of the base 54 is an upwardly extending generally cylindrical stem cr core 56. As may be seen from ~igs. 4 and 6, much of the core 56 is hollow opening to the lower side of the base 54. The upper end of the core 56 extends through the opening 36 in the container lower wall, the end 57 of the core 56 having a solid conical shape to facilitate insertion of the core into the opening 36. The portion of the core 56 actually extending through the opening 36 as viewed in Fig. 4 includes three radially extending circumferentially spaced ribs 58. Each rib further has a radially extending lug 60 which has a tapered 25 upper surface 6Qa which engages-the lower edge of the opening 36 with the assembly positioned as shown in ~ig. 4.
A tab 62 extends radiall~ outwardly from one edge o~
the valve member base 54 to form a convenient element for removing the valve member from the valve opening 36.
The assembly 40 further includes a valve closing means ~ -13-~6Z~

comprising a generally disc-shaped hollow member 64 which is made of flexible rubber-like material and defines an expandable in-terior chamber 66. Since the member 64 is flexible and stretchable, it might be thought of as a balloon or bellows-like member. The bottom side of member 64 includes a centrallylocated thickened throat 68 which defines a circular opening into the chamber 66. A circular plug 70 snaps within the throat 68 in the lower wall of the member 64. More specifically, the plug 70 includes a side wall 72 which slopes downwardly and outwardly and is slightly larger in diameter than the throat 68. A side wall 72 further includes an outwardly extending flange 74 that forms a continuation of the upper wall 76 of the plug. The throat 68 snugly engages the side wall 72 of the plug and the ; flange 74 snugly engages the lower wall of the chamber 66 sur-rounding the throat 58~ While the plug 70 snaps into position in the throat 68 to close the chamber 66, there is further pro-vided a resilient ring shaped retaining element 77, which surrounds the exterior of the throat 68 holding it in tight engagement ~ith the plug side wall 72.
The plug 70 further includes a lower guide portion 78 having a curved exterior which ~its within an opening 41 in the container wall portion 44 which supports the valve and valve actuating assembly 40.
A valve passage 82 extends centrally through the plug from the lower portion 78 and upwardly into a tubular portion 84 that extends above the upper wall 76. The upper end of the tube 84 is closed by a plate or wall 86. A hole 88 extends radially through the tube 84 to place the chamber 66 in fluid communication with the atmosphere around the assembly 40.

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1 Formed in the upper wall 76 of the plug 70 is an annular 2 recess or groove 90 in which is positioned a thin band 92 which 3 surrounas the tube 84 and extends over the valve opening 88v ~P
band 92 lS made of heat shrinkable material which shrinks and becomes permanently rigid at a predetermined temperature.
6 The balloon member 64 further includes an upwardly extendi~
7 nipple 94 which snugly fits within the cylindrical recess 55 -8 ln the lower wall of the valve base 54 as seen in Fig. 4. The 9 interior of the nipple 94 is hollow and is open to the chamber 66 when the chamber is expanded; however, in the position of Fig.
11 4, the upper wall 86 of the tube 84 of the plug 70 engages the 12 lower end of the nipple 94 and thereby limits the contraction of 13 the chamber 66. Loosely surrounding the nipple 94 is a heat 14 shrinkable band 96.
Operation of Embodiment of Figs. 1 - 7 in a Vacuum Autoclave . . . . .
16 Referring to Fig. 2, the container lid 12 is removed and 17 the articles 100 to be sterilized are placed within the base 14.
18 They are then loosely covered by a thin sheet of transparent 19 plastic material 102 which can withstand sterilizing steam temperatures. The lid 12 is then loosely placed in position on 21 the base 14 with the interior of the inner surface of the flans~
22 16 engaging the outer surface of the fl~xible gasket 22. In 23 this position, the lid or cover is closed in the sense that air 2~ cannot flow into the container pa~ the gasket but the cover is not fully closed onto the base.
26 A valve and valve closing assembly 40 is positioned within 27 l ¦ the re ss 38 es shown in Figs. 2 and 4. The components of the ~0 . .

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- 15 -~1GZUZ1 assembl~ 40 axe usuall~v proYided in an a~sembled condition where-in the band ~6 is first loosely positioned on the nipple 94 of the valve actuating member 64 and the nïpple is then pressed in~o the recess 55 in the lower end of the valve member. The valve is retained in this position by a slight friction fit. The assembly 40 is therefore i~serted into ~he recess 38 as a unit. Since the components are fle~ible, the upper end 57 of the valve core may be easily inserted into the container valve opening 36l al-lowing the lower end of the valve actuating member 64 to be snapped into position. The lower surface 78 of the core 70 con-~orms to the hold 41 in the container support wall 44 to properlyalign the assembly. The alignment ribs 58 on the valve core 56 properly align the valve with respect to the hole 36. Also, the outwardly extending lugs 60 limit the inward movement of the valve to tell the user of the equipment that the assembly is properly positioned. The tolerance of the components are relatively loose but yet the design is such that precise align-ment is not critical to obtain proper seating of the valve.
The valve closing assembly is primarly designed for use in a sterilizing apparatus which includes a high pressure steam cycle. Two widely used sterilizers are the so-called gravity autoclave and the vacuum autoclave. An example of the pressure and temperature cycles in one type of vacuum autoclave is il-lustrated in Fig. 8. The horizontal line 104 represents time.
T represents a temperature curve and P represents the pressure curve, with the line 104 indicating normal room temperature and pressure. When the container 10 is placed within the vacuum autoclave, a first vacuum environment îndicated by the section Pl of the pressure curve is first applied. Most of the un-sterili~ed air withîn the autoclave is withdr~wn as is the air 3~ within the container 10 since the in~eri~r of the container i~

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in communication with the interior of the autoclave by means of the valve opening 36 in the bottom wall of the con~ainer. The pressure within the autoclave is then once more allowed to return to ambient pressure by allowing steam into the chamber. A second vacuum cycle P2 on the pressure curve shown on Fig. 8 is then ap-plied which withdraws the steam within the autoclave which hasmixed with the small amount of remaining un~terile air. In some sterilizers, additional vacuum cycles of this type are employed.
High pressure steam is then introduced into the auto-clave causing the pressure as well as the temperature to rise as indicated ~y the curves T and P. The temperature and pressure curves are shown coincident at this time in that they both rise at the same time and the units of measurement employed are as-sumed to cause the curves to move in a coincident man~er. It should be understood that this is not intended to be a precise showing of the actual curves but only to illustrate that the temperature and pressure are both rising to their maximum levels during this phase. The high temperature steam of course cir-culates into the interiox of the container by way of the valve opening 360 Also, the high pressure high temperature steam also circulates into the chamber 66 by way of the valve passage 82 and the valve opening 88, noting that the cylindrical valve element 92 is spaced ~rom the opening 88 to permit such flow. Note that even if the valve band 92 is positioned loosely over the opening 88, the pressure differential between the chamber 66 and the surrounding autocla~e pressure cau~es the steam to flow into the ch~mber 66.
When the temperatures and pressures are neax their maximum, the heat of the steam causes the heat ~hrinkable sleeve 92 to shrink to its position shown in Fig. 5 wherein it closes the

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opening 88, thereby capturing a volume of high pressure high temperature steam within the chamber 66. This point 106 is shown in Fig. 8.
The steaming cycle continues for a desired period of time. Most autoclaves are adjusta~le to vary the duration of the steaming portion. The graph shown in Fig. 8 illustrates the steaming cycle to be of relatively short duration; however, the duration should be adjusted to fit the load within the container. A load requiring a particularly long period of time is one which încludes a large ~uantity of metal elements having considerable mass. For example, a large quantity of surgical tools would have considerable mass. Even more demanding, during the testing of the container, a load of steel bolts were placed in the unit. Such a load requlres a considerable period of time for adequate sterilizing in that it takes a considerable quantity of steam to heat the entire mass of the load to the desired sterilizing temperature. The surface of the heavy metal~items will remain relatively cool until the interior of the items are heated because of the conductivity of the material.
As the hot steam strikes the cooler metal, some of the steam condenses and drips onto the floor or bottom wall 28 of the container. Although this liquid would be sterile at the end of a steriliæing cycle, it is desirable that the water be re-moved from the container ~o that the container will be as dry as possible during storage. It is for this reason that the bottom wall 28 of the container i~ slightly sloped so that the ~ater will flow towards and out the opening 36. Regardless of the length of the ~teaming cycle, the valve 36 will r~main open in that there is no force for closing it. Howevert when the steaming cycle is interrupt~d~ the pressure ~uickly drops as illustrated by the section P4 of the curve. A final vacuum cycle is then applied to withdraw the steam as indicated by the

-18-cuxve section P4. Following this 9 the vacuum is removed by allowing the introduction of filtered exterior air so that the pressure within the autoclave returns to room pressure.
As the pressure in the autoclave is dropping from its maximum, the captured pressure within the chamber 66 causes the balloon 64 to expand. Since the pressure drops rapidly into ~
vacuum phase, the balloon 64 expands quickly into the condition shown in Fig. 5 wherein the nipple portion 94 may be seen to have moved upwardly a considerable distance thrusting the valve member 54 against the annular valve seat 37 surrounding the valve opening 36. As can be seen from Fig. 5, a large portion of the inner upper surface of the flexible resilient base p~rtion 54 of the valve engages the valve seat 37 to form an excellent seal.
Note also that the valve seat 37 has a concave configuration or curves inwardly towards the interior of the container and that the valve member conforms to the valve seat surface. The exact point of closure of the val~e is not critical but the valve will typically close in the area indicated by the point 110 on the pressure curve in Fig. 8.
It should be noted from Fig. 5 that the balloon member 64 is constructed to insure its expansion into the configuration illustrated. That is, the outer edge walls of the member 64 are ~omewhat thicker than some ~f the ad~acent portions so that the balloon does not expand radially. Also, the upper wall of the member 64 includes a thickened annular rib portion which causes the balloon to take the general configuration illustrated which insures that adequate upward thrust of the valve closing member is obtained.
It s~ould also be noted that sufficient thrust is required to force the lug~ 60a on the valve core 56 through the ~162~21 opening 36. The purpose for these lugs in addition to initially properly positioning the valve is to make sure that the ~alve does not close prematurely due to a temporary drop in the pres-sure of the steaming cycle. That is, it has been found that some autoclaves have a considerable pxessure variation as the steam is fed through the unit. Thus, a drop in pressure in the middle of the steam phase could cause the valve to close. However, the presence of the lugs 60 requires a sufficient force that normal variations in the steam pressure will not close the valve. About a 10 psi pressure drop is required to close the valve.
Although the container is now closed by virtue of the valve 54 and the gasket 16~ recall that the lid 12 was initially only loosely positioned on the base. Thus, as the pressure drops during phase P4 of the pressure cycle, a pressure differential between the interior and the exterior of the container is initiated. However, a unique quality of the gasket is that it will permit leakage out of the container with a relatively small pressuxe differential. Consequently, the steam that was within the container when the valve closed is still withdrawn from the container by the vacuum cycle. This is highly desirable because 2C it means that the contents of the container are left in a dry and sterile condition. Thus, even at the bottom of the vacuum cycle, the lid 12 is still only loosely positioned on the gasket 16. Nevertheless, the flexible resilient nature of the gasket is such that gas cannot flow into the container. Thus, the gasket during this phase of the cycle essentially acts iike a check valve.
When external filtered air is introduced into the auto-clave allowing the pressure to return to ambient, the vacuum which wa-~ applied to the autoclave still remains within the con-3D tainer, as indicated by the dotted line PC The gasket 16 and 2~

the valve 54 prevent this external air from entering the con-tainer. Although such air is filtered it is nevertheless not sterilized and hence, it is important that this air not entex the container to best maintain sterility.
Since the incoming air cannot enter the container, the pressure of this air quickly forces the lid downwardly into its maximum closed position with the lid flange 22 tightly pressed against the gasket 16 so as to more positively prevent external air from entering the container. Similarly, the exterior air presses against the valve member 54 causing it to remain tightly seated on the valve seat 37 as illustrated in Fig. 6.
Referring again to Fig. 8, the temperature in the auto-clave also drops rapidly once the steaming cycle is interrupted, but then remains at an eleva~ed level and slightly rises during the final vacuum phase, since the autoclave is heated. When the container is removed from the autoclave, the temperature gradually returns to normal. The reduction in temperature within the autoclave and later outside the autoclave eventually also cools the steam within the balloon chamber 66 causing a reduction in pressure within the chamber 66. This causes the resilient balloon member 64 to contract and revert to a position close to that it originally assumed, as illustrated in Fig. 6. The valve member 54 is o course no longer supported by the balloon 64 in that the ambient pressure is tightly holding the valve in position without any other support. This force is so strong that the weight of the inflatable chamber memhers 64 and 70 is of no consequence with respect to the seal produced by the valve, but ; usually the enlar~ement of the valve recess S5 results in the members following and returning to the position shown in Fi~. 6.
However, if the friction bet~een the nipple 94 and the tubular ~62~

- recess 55 is sufficient, the valve closing member will be lifted from its seat resting on the support wall 44. The valve closing member may remain in either of these two positions or it may be withdrawn or recycled for an additional use. It can of course, not be reused unless the plug 70 is withdrawn from the flexible member 64 and the heat shrink band 92 removed so that the valve opening 88 once more permits csmmunication between the chamber 66 and the exterior. By providing a new heat shrink band 92, the valve closing member can be reused. Normally, such re-cycling will be performed~ by people other than those using the container.
Note from Fig. 6 that the heat shrink band 96 has shrunk tightly onto the nipple 94 because of the high temperature steam.
This bana 96 is colored differently from the nipple 94 to pro-i vide an indication to the user of the container that the valve moving member has been used. Thus, this indicator band shouldbe removed when the internal heat shrink valve element ic re-placed. A new indisator band should be loosely positioned over the nipple when it is inserted in a valve which is to be reused.
With the valve member closing the opening in the end of the container, the contents of the container may be maintained in sterile condition for a long period of time. So long as the ~valve is in the position shown in Fig. 6, an observer will know that the contents are still sterile. If the vacuum within the container should be lost, the valve will withdraw slightly from the tightly sealed position due to the weight of the valve and its memory. This will tell the observer that the contents may no longer be of maximum sterility. However, the lug~ 60 on the valve core 56 continue to hold the valve in the sealed position shown in Fig. 7. While such seal has permitted so~e air to 3o ~i6~

enter the container as the vacuum was lost, the contents still have a minimum amount of contamination, and it is much less than that which relatively quickly results with present day methods of wrapping items to be sterilized and stored in towels.
When the csntainer is to be opened and the valve is still tightly sealed as shown in Fig. 6r the valve member may be readily removed by pulling on the tab 62 attached to the valve member. As mentioned above, the valve member can be reused if desired, assuming it has not been held in a valve closed position so long that the material no longer has adequate resiliency to maintain its original shape.
The container cover may then ~e removed, although it may still be somewhat tightly in position even though the vacuum has been removed. To facilita~e removal of the cover, the base may be held with one hand and the cover lifted by means o the tab 24 located on one end of the cover.
Normally, the container will have been removed from a storage ~ocation into the operating area before it is opened.
When the cover is removed, there is a possibility that some dust or other contamination that may have accumulated on the exterior of ~he cover during storage could drop into the con-tainer interior. It is for this reason that the additional barrier layer of flexible plastic 102 was installed over the instruments prior to the sterilizing operation. This barrier layer can now be carefully removed by grasping one end and withdrawing it over one edge of the container so that hopefully an~ dust that may have fallen into the container will be re-moved with the barrier layer, or at least such dust will not ~all directly onto the sterile instruments.

~ 6;Z~2.~

~ravity ~utoclave Operation While a vacuum autoclave sterilizing cycle is pre-ferrable from a standpoint of sterility and from a standpoint of best operation of this container, a large number of gravity autoclaves are still employed and the valve and valve closing S assembly 40 of this invention can accommodate such cycle as well. Referring to Fig. 9 it may be seen that there are no vacuum cycles applied but instead high pressure steam is simply applied and then withdrawn. The valve and valve closing assembly 40 is used in the same manner as described above in connection with the vacuum cycle. The valve member 54 is closed at ap-proximately the same location ll0 on the pressure curve~ Also, as the pressure is exhausted from the autoclave, pressure is exhausted from the container past the gasket in the same manner as described above. However, the only means for creating a vacuum within th~ container which will draw the lid more tightly into closed position and will hold the valve member 54 in tightly sealed condition is that vacuum which is created as the temperature of the small amount of residual steam within the container drops. The vacuum created in the container will follow a line more proportional to the temperature curve in-dicated at Tl in ~ig. 9. Thus, for a period of time, there may be însufficient pressure differential to hold the valve member 54 in the tigh~ly sealed position shown in Fig. 6.
Instead, it may temporarily drop to the position sho~n in Fig. 7 ~herein the lugs 60 retain the valve member in a sealing con-dition which prevents air leakeage into the container. Note that the outer periphery of the valve member i~ oriented to properly engage the valve seat in that condition to prevent leakage into the container.

1~1L62~2~

As the temperature of the r~sidual steam within the container drops further, an adequate pressure differential is created which will force the valve member back into ~he tightly sealed condition of Fig. 6. Also, i~ will pull the lid tightly into a sealed position on ~he gasket 16. The pressure within the container is indicated by the dotted line PC in Fig. 9. It should be appreciated that a relati~ely high vacuum is obtained even with the gravity type autoclave simply due to the pressure drop which is created as the residual steam condenses. While it is desirable that the contents of the container be com-pletely dry, a small amount of sterile water such as a ~ew dropswithin the container does not present a significant problem.
However, to keep such moisture away from the items in the container, a small amount of desiccant or other moisture absorbing material may be positioned in the container, with suitable means to isolate the desiccant until the end of the ~ycle. Such an arrangement is shown in Fig. 10 which illustrates an expandable balloon member 264 which is identical to the member 64 in Fig. 4 except that the upper wall 265 has a breakable or rupturable portion 267 which is much thinner than the adjacent wall thickness. The chamber within the member 264 is illed with desiccant which is exposed to the interior of the container at the appropriate time to absorb residual moisture. In use, the inflatable member 264 is filled with a suitable dry desiccant 269 in granule form, which leaves a quantity of air in the chamber surrounding the granules. A-plug 7Q carrying a heat shrink band 92 like that shown in Fig.
4 is then inserted in the lower wall of the inflatable membPr 264 in the manner discussed above. The unit i~ then heated in a~ oven to stexilize the desiccant and to sterilize the interior ~L:IÇi2~

of the inflatable member 264. During this heatin~ process, the heat shrink tube 92 will shrink and close the valve opening leading to the interior of the inflatable member 264, capturing a small volume of air that was in the oven. The proper time for rterilization at a given temperature is allowed. The member is then cooled an~ in effect becomes a small desiccant bomb which will rupture under the proper pressure conditions.
When the container 10 of Fig. 1 is to be used in a gravity autoclave, one of the sealed members 264 filled with desiccant 269 is placed into the container along with the items to be sterilized. When the sterilizing environment is applied to the container, it can not enter the desiccant bomb 269 because it is sealed. However, at the end of the sterilizing cycle, when a vacuum is quickly created in the container as the residual steam in the container is cooled and condenses, the pressure is not reduced as quickly within the member 264 because the air in the member remains gaseous. Consequently, the member inflates or expands as the surrounding pressure within the container falls and the thin wall section 265 will rupture exposing the desiccant to the interior of the container.
Another aspect of using the container in a gravity autoclave is that the container is initiall~ filled with un-sterilized air ~hen it is placed in the autoclave. When steam is applied, it mixes with the air and sterilizes it. However, there is some possibility that a pocket of air may be trapped within the container near the end of the container opposite from the valve opening in that the air is heavier than the steam and circulation may not be complete simply by having the valve open.
Thus, as a further assist to adequate circulation, there is shown in Fig. 11 the end of the container opposite the valve assembly wherein a heat responsive fuse-like el~ment 270 is shown holding the lid 12 spaced slightly from the base 14. The element 270 is inserted in a hole in ~he lid tab 24 with an interference fit in a manner to be axially fixed and supported by the lid. A horizontally extending stop 272 on the element 270 and the lower end of the element 270 engage the side wall of the base to hold the lid in the spaced position shown. The element 270 is made of a material which will soften after being subjected to the high temperature steam for a predetermined period of time. ~hus, the lid is partially open when steam is first applied with the result that the steam can circulate beneath the lid into the container displacing the air in the container out through the open valve in the bottom of the con-tainer. When the element 270 softens, the lid simply falls into its initially closed position as discussed above in con-nection with Fig. 2; and the remainder of the cycle is as previously discussed. Other similar fuse-like arrangements may be employed ~or temporarily holdlng the lid ajar.
Figures 12 and 13 Figs. 12 and 13 illustrate an alternate embodiment of the valve and valve closure mechanism as used in an identical container. Referring to Fig. 12 there is shown a valve and valve closure assem~ly 140 ~hich includes a valve 152 ha~ing a saucer shaped base 154 and a ~entrally located upwardly extending core or stem 156 having a conical tip 157. Like the valve 52, the core 156 is provided with three ribs 158 having radially extending lugs 160. A tab 162 is formed integral with the base 154 for xemoving the valve from the valve opening 36.
Also ~ormed integral with the valve base 154 is a cylindrical portion which forms a piston 164. This piston is slidably positioned within a cup shaped member 165 defining a variable or expandable chamber 166 in cooperation with the piston 164. An annular bead 164a on the lower end of the piston en-gages the walls of the cylinder 165 to form a piston ring.
The cup shaped e~linder has a centrally located inwardly extending portion 170 which limits the movement of the piston 164 into the cylinder 165. One or more valve openings 182 place the chamber 166 in fluid communication with the exterior of the ch~mber. Surrounding the central portion 170 and the valve openings 182 is a heat shrink band 192 similar to that shown in Fig. 4. As seen in Fig. 12, the band is spaced from the ~alve~
openings 182 so that fluid communication into the chamber 166 is maintained.
In operation, the assembly 140 functions essentially like;the assembIy 40 previously described. The heat band 192 shrinks at a predetermined temperature level indicated at point lD6 on the curves in Figs. 8 and 9. Thus, a quantity of high temperature, high pressure steam is captured within the chamber 166. ~hen the pressure drops within the autoclave, the cap-tured steam in the chamber 166 expands and reacts a~ainst the piston 16~, forcing it upwardly and outwardly so that the valve 154 is sealed on fhe valve seat 37 as shown in Fig. 13. As the vacuum is created in the container in the manner discussed 3~ ~

.

above in connection with the two sterilizing cycles, the re-sulting pressure differential will hold the valve in the seated position shown in Fig. 13.
With the arrangement of Fig. 13 it is intended that the cylinder 165 remain with the container in the position shown.
When the container contents are to be used, the valve 152 may be removed in the same manner as the valve 52 namely by pulling on the tab 162.
It should be understood that with either expand~ble chamber mechanism, a simple check valve is satisfactory for capturing steam in the chamber means for use in a gravity auto-clave. Such a valve will permit flow into the expandable chamber but not out. The temperature responsive valve is employed so that in a vacuum autoclave cycle, the chamber does not expand during eïther of the initial vacuum cycles. The heat shrink bands 92 and 192 actually function as check valves after they initially shrink in that the material is rubber-like at that time. However, when the material later cools, it becomes permanently rigid.
Description of Fi~s. 14 - 16 The pre~erred form of the container 300 illustrated in Fig. 14 includes an upper somewhat dome-shaped portion or lid 312 having an upper wall 312a and depending side walls 312b.
The lower portion of the side walls 312b flare outwardly and downwardly forming a flange 312c which mates with the base 314 2~ to form ~ closed container. As may be seen, the base 314 includes a bottom wall 314a which is generally flat, but the central portion of the ~all is raised and slopes outwardly to a peripheral groove portion 314b. As can be seen from Fig. 15 the groove portion 314b includes an upper inner generally ver~ical wall 314c whiçh extends downw~rdl~ from the periphery -2~-of the bottom wall 314a. The wall 314c is formed integral with a generally horizontal flange 314d which in turn joins with a ~-shaped lower portion 314e. The outer portion 314f of the U-shaped portion 314e extends upwardly and outwardly to about the level of the periphery of the bottom wall portion 314a. A
plurality of drainage holes are formed in the bottom of the U-shaped porti~n 314a, one of such holes 316 being shown in Fig. 15.
The container base 314 is also provided with a pair of handles 318 connected to the groove wall portion 314f, ~ocated on one side of the container base is an upstanding wall or support 320 attached to the outer upper portion 314f of the ~-shaped groove 314b. A cylindrical actuator housing 322 with snap-on cover 323 is connected to the support 320 by suitable means. In the bottom wall 314a of the base there are provided lS a plurality of up5tanding hollow projections 324 aligned with a mating set of projections 326 formed on the lid 312. These projections facilitate stacking of a series of containers in storage. Positioned immediately above the base 314 in the illustration of Fig. 14 is a basket 330 having a bottom wall 2Q shaped and sloped to ~it the bottom wall 314a of the base 314.
The basket 330 also includes a series of projections 332 which mate with thP projections 324. A plurality of holes 334 permit condensate to drain from the basket. Positioned immediately abo~e the basket 330 is a cover or lid 336 which mates with the periphery of the ~asket 330.
Also mounted on the base 314 is a resilient gasket 338 ~hich cooperates with the lid and the base to seal the container.
As may be seen from Fig. 15, the gasket includesan innergenerally -3L~ 2 .

1 vertical surface that tightly enqages the wall 314c on the base, 2 while the lower edge of the gasket engages the flange 314d in 3 Ithe base groove. The gasket 338 includes an outer flexible 4 ¦flange-like portion 338a which engages the lid and deforms to 5 ¦provide a sealing surface, as may be seen in Fig. 16_ 6 I Within the actuator housing 322 is positioned a lid holain.
7 ¦actuator mechanism 340 which includes a ~alloon-li~e membër 342 8 ¦comparable to the member 64 shown in Figs. 4 and S. The outer 9 ¦end wall 342a of ~hemember 342 includes a centrally 1 ~ ted ~ckened 10 Ithroat 342b which defines a circular opening into the chamber 3'3..
11 ¦A ring-shaped plug-like element 346 including an outwardly 12 ¦extending flange-like portion 348, having an outwardly acing 13 ¦groove, snaps within the throat in the wall 342a. While the 14 ¦element 346 closes the chamber 343, there is further provided a 15 ¦retaining ring 350, which surrounds the exterior of the throat 16 ¦holding it in tight engagemen~ with the groove in the flange 39E.
17 ¦ The actuator mechanism 340 further includes a hollow pin 3'4 18 ¦having one end 344a securea to the interior of the plug 346 and 1~ la central portion extending through the member 340, out an open~g 20 ¦in a throat portion 342c in the other end 344d of the balloon, Zl ¦and through~a hole in the support wall 320. The other end 344b 22 ¦of the pin 34~ extends into the path of the lid 312 as it is 23 ¦opened and closed. In Fig. 15, the lid is shown being supportea .
24 I on the pin 344 which is supported by the support wall 320. The 25 Ipin and the support wall 320 are sufficiently rigia to support 26 ¦the lid in cantilever fashion, as shown~ The pin, of course~
2~1 also supports the balloon-like mem~er 342.
~8¦ The pin end 344a secured to the plug me~er 346 is open, 25 ~thus defines a passage leading to ~ hole 352 in the wall of the 2~

pin that ~pens to the interior chamber 343. Thus, the chamber 343 is in fluid communication with the exterior of the balloon 342. A thin ri~g or band 354 surrounds the tube 344 and extends over the opening 352 to serve as a valve. The band 354, like the band 92 in Fig. 4, is made of heat-shrinkable material which is initially flexible, and which shrinks at a predetermined temperature, and then becomes rigid when the temperature is lowered.

Opera_ on of ~mbodiment of Figs. 14-16 In use, the surgical instruments or other items to be sterilized are placed within the basket 330, with the cover 336 on the basket. The basket is then positioned on the base 314, and the lid 312 placed onto the base with one edge of the lid supported by the pin 344 of the actuating mechanism 340, as shown in Fig. 15. The other side of the lid is, of course, positioned in the groove 314b of the base engaging the gasket 338. The entire container is then lifted by ~;he handles and placed in an autoclave or other sterilizer to be subjected to a sterilizing cycle.
The operation of the actuator mechanism 340 is similar ~0 to the valve closing means described above in connection with Figs. l - 7, when subjected to sterilizing cycles like that ~hown in either Fig. 8 or Fig. 9. When high-pressure steam is applied to the container, it enters the container beneath the open lid to perform the desired sterilizing function. If any 25 steam is condensed, in striking the ~older items in the con-tainer, it will flow off the bottom wall 314 t~wards the gasket 338 and the groove 314b, where it can escape through the drainage holes 316. The high pressure steam also enters the expandable chamber 343 by way of the hollow pin 344 and the ~6~

valve opening 352. The temperature of the steam will cause the valve element 358 to shrink, closing the opening 352 and capturing a quantity of high-pressure, ~igh-temperature steam within the expandable chamber 343. The steaming phase of the autoclave cycle can continue for whatever duration is desired and the pin 344 will continue to hold the lid 312 ajar, thus assuring that condensate can drain from the container~
When the steaming phase is over and the steam is allowed to escape from the autoclave~ the result;ng pressure drop within the autoclave causes the steam captured within the chamber 343 to expand the balloon into the shape or condition shown in Fig.
16. As may be seen, the inner end of the throat 342c of the member 342 engages the support 320. Consequen~ly, when the balloon expands, the only direction which it can move is to urge its outer end 342a together with the plug 346, outwardly away from the container lid Since the pin 344 is secured to the member 346, the expansion of the chamber retracts or wi~hdraw~
the pin 344 from beneath the lid 312, thus permitting the lid to fall into sealing position on the gasket 338 as shown in Fig.
16. The pin 344 is withdrawn partially into the chamber 343, although as c~n be seen, the tip of the pin end 344b remains in the support ~all 320 to provide support for the actuator mechanism 34QO The pin 344 and the member 342 are, of course, constru~ed to permi~ the sliding movement of the pin within the member 342 without leakage of the steam from the chamher.
Thus, the container will close at approximately the same location on the curves in Figs. 8 and 9 that the ~alve will close in the embodiment of Fiqs. 1 ~ 7. That is, the lid will fall as the pressuxe is falling within the autoclave.
Also, as in the other arrangement, the gasket 338 will permit vapor to escape from the container if the pressure on the exterior IL6~2~
. . . ~

1 of the container is further reduced, but it will prevent fluid flow from entering the container. ~hen the autoclave is openel 3 and the pressure returns to normal, the lid is tightly kept on 4 the base as the vacuum in the co;ntainer. The container can b-stored in this sterile condition for an extended duration.
6 When the container is to be opened, a relief valve 36~ in 7 the top of the lid 312 may be pulled open to equalize the press--re 8 inside the container with that surrounding the containerJ thus 9 enabling the lid to be lifted. Normally, the container will b-carried into the room where the contents of the container are-11 to be used. Thus, if the container is fillea with surgical 12 instruments, it would be carried into the operating room. The 13 lid would then be removed and the basket 330 would be lifted fro~
14 the container together with the cover 336 and carried to the sterile operating area. The purpose for the cover 336 is to 16 prevent the possibility of dust or other unsterile material frG~
17 falling from the lid 312 into the basket 330 when the lid is 18 being removed from the container. The sterile cover 336 is the~

19 removed and the sterile instruments removed as neede~ during thn

20 operation.

21 When the container is to be reused, it is a simple matter ,o

22 remove the cap 323 from the actuator housing 322 and replace the

23 actua$or mechanism 340 with one having a heat-shrink valve 354

24 which is not yet shrunk on the tube 344.
Embodiment of Figs. 17 - 22 26 Figs. 17 - 22 disclose a portion of a container similar to 27 that shown in Fig. 14 incorporating a different lid holaing a 28 release mechanism. A lever 422 is pivota~ly mounted on the 29 c-xterior side of a supporting wall 420 connected to a container ~0 base 414. .Sore specifically, there is a generally vertically . . ..

11626~23L

extending pivot pin 424 mounted on the wall 420, and the lever 422 has a pair of lugs 422a receiving the pivot pin 424 to enable the lever to pivot horizontally about the pin 424- The lever is preferably made of a suitable rigid plastic material similar to the container material. On one end 422b of the lever 422 is formed a hinged flange 428 which extends above the support wall 420. On the other end 422c of the le~er there is mounted a pin 430 which extends through a hole in the support wall 420. Surrounding the pin 430 is ~ coil spring 432 with one end of the spring engaging the outer surface of the support wall 420 and the other end of the spring engaging the lever.
Consequently, the spring urges the lever into the position shown in Figs. 17 and 18 with the flanged end of the lever supporting the lid 412. At the same time, the pin 430 is out of the path of the lid. Note also from Fig. 18 that the hinged flange is somewhat higher than the pin.
Extending between the lever and the exterior of the support wall 420 is an inflatable chamber actuator 440, similar to that shown in Fig. 15 but without the pin 344, or similar to the expandable chamber 64 shown in Figs. 4 and 5. The actuator 440 may be supported by either the lever 422 or the wall 420, or by both. In the arrangement shown, the plug 446 is made of two parts, one part 446a extending through a hole in the lever, and an outer cap 446b threaded onto the part 446a to mount the actu~tor on the lever.
Operation of Embodiment of Figs. 17-22 In use, the container is positioned in a vacuum-type autoclave with the lid 412 supported on the flanged end of the lever as shown in Figs. 17 and 18. When steam is applied to ..... , ., .. , .. , . ;. " .,.. , . .. ... ~, .. . . . . . . . . .

-1 the container, the temperature responsive valve (not shown in 2 Fig. 17~ within the actuator 440 will close,capturing a quantit~
3 of high-pressure steam. When the steaming phase is over and t~
4 pressure is allowed to drop withi~ the autoclave, the captured 5 steam within the inflatable chamber will expand and pivot the 6 lever against the urging of the coi1 spring into the position 7 shown in Fig. 19. This movement of the lever withdraws the 8 flanged end of the lever from beneath the edge of the lid as g shown in Fig. 20. Thus, the lid starts to fall towards the bas-~10 However, the pivoting of the lever which withdraws the flanged 11 end of the lever has rnoved the pin 430, attached to the other 12 end of the lever into the path of the lid so that the pin 13 supports the lid, as shown in Fig. 20. Note that the lid is 14 still spaced from the gasket 438 so that the container is still 1~ not yet closed and no pressure differential is created between ;e 16 inside and the outside of the container. Thist of course, is 17 similar to that in the arrangementsof Fig. 1 - 7 and 14 - 16 in 18 that the gaskets act as one-way valves when the lid is positîon^d 19 on the base. However, at the maximum vacuum point in the vacuu~
cycle the lid is still open; and hence, when the pressure in 21 the autoclave is allowed to increase,-the container pressure ca~
2~ rise also. This is in contrast to the earlier arrangemen~s.
23 As the pressure surrounding the expandable chamber increas_~, 24 the chamber will contract closer to its original shape as shown in Fig. 21. Thus, the spring returns the lever to the position 26 sho~n in Fig. 21. This movement retracts the pin from its lid 27 holding position and, at a predetermined point, allows the lid 28 to fall into closed position on the gasket 438, as shown in 29 Fia. 22. The movement o~ the lever pivots the flanged end of 30 .

.. . . ... ,. , . , , _ ~

~i2C~

the lever towards the lid; but since that end is hinged and the lid wall is sloped, the end of flange 428 simply flips up harmlessly as shown in Fig. 22. Alternatively, the slope of the lid and the exact configuration of the ~lange may be arranged quch that the flanged end does not interfere with the lid so that the hinging arrangement is not needed.
Thus, with the arrangement of Figs. 17 - 22, the lid may be closed somewhere between the maximum vacuum point shown in Fig. 8 and the ambient preqsure line 104. The exact location may be precisely determined and easily modified in selecting the length of the retaining pin. For example, the pin may be threadably mounted in the lever and adjusted inwardly or out-wardly. In other wordsl the extent of the vacuum within the closed container may be easily controlled, and this in turn will determine the necessary strength of the container walls.
Thinner walls of course require less plastic and hence, are less expensive As explained above, such an arrangement is practical if the air being introduced into the autoclave to equalize the pxessure ls suitably filtered so as to be sterile. While present autoclaves do not provide this, future ones may.
2~
' ~' .

.. , , , .. ~ . .. , .. . ., . .. . . ~ . . . . . .. . .

Claims (6)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of sterilizing and storing items comprising the steps of placing the items to be sterilized in a container, placing the container in a sterilizer with the exterior of the container in fluid communication with the interior of the container by way of access means to the interior of said container, operating the sterilizer to provide a sterilizing cycle including applying a high pressure sterilizing environment to the interior and exterior of the container and then permitting the environment to be withdrawn from the sterilizer, closing said container access means, after the contents of the container have been sterilized but before the container is subjected to an unsterile environment, by the use of means responsive to a substantial reduction in the pressure of the environment which occurs as the high pressure environment is withdrawn or escapes from the sterilizer, and triggering the operation of said pressure responsive means by means responsive to a predetermined temperature.

2. The method of Claim 1 including initiating the operation of said pressure responsive means by means responsive to the temperature of said environment.

3. The method of Claim 2 wherein the container has a valve in one wall and said pressure responsive means includes means defining an inflatable chamber which is positioned to move the valve into closed position when the chamber expands.

4. The method of claim 3 wherein said pressure responsive means is an expandable chamber which produces a force for closing or releasing said access means, said expandable chamber being initially open and then closed in response to the temperature of said environment to capture a volume of the sterilizing environment.

5. Apparatus for carrying out the method of claim 1, comprising:
a container;
means, including a sterilizer, for applying a high pressure sterilizing environment to the interior and exterior of said container;
means for permitting said environment to be withdrawn from said sterilizer;
pressure responsive means for closing the container in response to a substantial drop in the pressure of a gaseous environment applied to the container; and temperature responsive means for permitting operation of said pressure responsive means after a predetermined temperature of said environment is reached.

6. Apparatus according to claim 5 wherein the container is of sufficient strength to withstand a high pressure environment.