CH621066A5 - Method and device for the sterilisation of articles, especially surgical instruments - Google Patents

Description

The invention relates to a method for sterilizing objects, in particular surgical instruments, in which method the objects are accommodated in a container and in which the container is sterilized from the outside, the outside with the inside of the container at least up to to achieve sterility, and an apparatus for performing this method.

The most common conventional method for sterilizing surgical instruments and other medical objects is to place them in a towel, which is enclosed by another cloth, sealed with an adhesive tape and placed in a sterilizing autoclave. The sterilizing steam introduced into the interior of the autoclave penetrates the porous material that surrounds the objects to be sterilized. The moisture is then removed by a drying process inside the autoclave. The sterile package is then either used immediately or kept for future use. If the package has not been used within a certain period of time, such as twenty days, it must be replaced in the autoclave for re-sterilization. It is estimated that two thirds of sterilization work in many hospitals is for items that have not been used within the allowable retention period. Of course, this is an expensive and unusable process.

There is therefore a need for a practicable and reliable method and corresponding devices for sterilizing objects, for storing and otherwise handling such objects and for maintaining sterility. One might think of using a container that surrounds the items to be sterilized and that would be completely sealed before being placed in the autoclave, but the contents of the container will not be exposed to the action of the sterilizing steam. Instead, the atmosphere within the verse5

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the container must be sterilized using dry heat, which means that higher temperatures and longer periods of time than in moist heat are required. Also, an autoclave typically has significant pressure differences as a result of vacuum phases in which air and steam are drawn off, and the autoclave has a pressure phase in which the steam is applied. A sealed container inside the autoclave would therefore be exposed to these pressure differences with its exterior, which could break or otherwise damage the container.

The present invention is therefore based on the object of specifying a method and a device with the aid of which it is possible to sterilize objects in a simple manner, to keep the sterilized objects as long as possible and to avoid re-sterilization when the objects are not used, the components of the The device should not be adversely affected or damaged by pressure differences in the autoclave.

This object is achieved in the method of the type mentioned at the outset as defined in the characterizing part of claim 1.

Embodiments of the invention are described below with reference to the drawing.

Fig. 1 shows an exploded perspective view of a container according to the invention with a lid, insert and lower part;

Fig. 2 is a cross section of the container;

Fig. 3 is a cross section on the line 3 - 3 in Fig. 1 and illustrates a vacuum display device;

Fig. 4 is a top view of the canister valve;

FIG. 5 is a cross section of the valve according to FIG. 4 with the valve closed;

Fig. 6 is a cross section of the valve with the valve open;

7 is a perspective view of a component used to hold the valve open;

8 is a cross section of a second embodiment of a valve for the container of FIG. 1, the valve being shown in the open position;

FIG. 9 is a cross section of the valve according to FIG. 8 in the closed position;

FIG. 10 is an enlarged, broken-away section of a part of the valve according to FIG. 8, the open position being shown in solid lines and the closed position in broken lines;

Figure 11 is a side view of another embodiment of a resilient plug member inserted into the wall of a container, which is cylindrical in shape and also has a different shape of seal;

Figure 12 is an exploded perspective view of the valve of Figure 11;

Fig. 13 is a perspective view of the valve of Fig. 11 in a cocked position and ready for insertion into the container;

14 is a graphical representation of a conventional autoclave cycle.

The container shown in FIG. 1 has a lower part 10, a lid or closure 12 and an insert or a bowl 14. As can be seen, the container has an elongated and relatively flat shape with rounded corners. The lower part has a bottom wall 16 and a side wall 18, which ends in a rounded upper edge 19 and has a downwardly inclined flange 20 and then a further, horizontally extending flange 22. The cover 12 has an upper wall with a central flat section 24 and a rounded, downwardly sloping section 25, an edge part 26 surrounding the latter, which is inclined upwards, then horizontally and then runs downwards and outwards and forms a shape, that fits over the upper edge 19 of the lower part 10. The cover 12 also has a short, outwardly extending circumferential flange 28.

A wide flexible seal 30, which is shown more clearly in FIG. 2, is attached to the cover 12. It has a resilient part directed downwards, which resiliently engages the wall 20 of the lower part 10 directed downwards and outwards. If the cover 12 is pressed firmly onto the lower part 10, a seal is formed where the lower edge of the seal 30 touches the wall 20, as illustrated in FIG. 2. The upper end of the seal 30 also fits tightly into the cover 12 and forms a seal with it. As FIG. 2 further shows, the lower part has a multiplicity of feet 34 which support the bottom wall 16 of the lower part 10 somewhat above the base or contact surface.

The container is further provided with a pair of flexible tethers or bands 36, one at each end of the container. Each strip 36 has a retaining pin 37 at each end and fits into a slot 38 formed in the flange 22, so that the end of the strip is held in this position by means of the pin 37. The strip extends over the lid 12 to positively hold it in place and to keep the container sealed after it has been sterilized.

The shell or insert 14 has a shape that corresponds to the interior of the lower part 10. The shell 14 has an upwardly extending handle 15, which is dimensioned and designed such that it lies against the inner surface of the lid 12 when the lid is sealed to the lower part 10. The handle 15 additionally provides a reinforcement for the lid 12 in the event that a high vacuum exists inside the container.

A vacuum display unit 42 is arranged at one end of the cover 12. This unit 42 has an upper, flexible member 43 which is held in the sealing position with respect to the cover 12 by a plate 44 which fits into a recess in the flexible member 43. The plate 44 is held in the direction of the cover 12 or is pretensioned by means of a screw which is screwed into the plate 44 through the cover from the underside thereof. The screw has an internal longitudinal passage so that the interior of the resilient member 43 is exposed to the pressure within the container.

1, one or more valve openings 50 are formed in the bottom wall 16 of the lower part 10. 5 that the bottom wall 16 of the container is formed with an annular, outwardly extending projection 52, which has an outwardly facing surface 53. The bottom wall 16 extends somewhat inward from the projection 52 and thus forms a flat, circular recess or cavity 54 and a circular wall part 55.

A valve arrangement 58 is fastened to the circular wall part 55 by means of suitable fastening means. The valve assembly 58 has a valve member 60 which is made of rubber-like material and has a flat circular lower part 62 and an upwardly extending annular side wall 64 which in turn has an inner surface which resiliently abuts the outwardly extending wall surface 53, to seal access from the outside of the container to its interior through the valve opening 50. A pair of stiffening plates 65 and 66 are embedded in the bottom wall 62 of the valve member 60 to give this bottom wall some rigidity. On the plate 65, a pair of retaining screws or pins 68 are attached, which extend through support tubes 70 and through holes in the wall 55 and which on s

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the wall 55 are fastened by suitable nuts which are screwed onto the ends of the screws 68. The connection is such that the annular wall 64 of the valve member 60 is biased in sealing contact with the wall surface 53 in the normally closed position.

An edge of the valve member 60 is provided with an upwardly and outwardly extending portion which forms a manually operable valve opening lever 74. An extension of the plate 66 is embedded in the lever, so that when the lever 74 is pressed down by hand, the valve member 60 can be moved into an open position shown in FIG. 6. As shown, the resilience of the valve member 60 is such that it normally wants to automatically assume the closed position shown in FIG. 5. If desired, suitable spring members can additionally be used to push the valve member 60 even more firmly into the closed position. As an exemplary embodiment of this, a coil spring 75 (see in particular FIG. 4) can be arranged in the upper surface of the wall 62 of the valve member 60, one end of the coil spring engaging the plate 65 and the other end engaging the plate 66, so that there is a force that pushes the valve member 60 into its closed position.

In order to hold the valve in the open position, a holding or tensioning device is provided which has a support member 76 which is suitably fastened to the plate 66 and the bottom wall 62 of the valve member 60. The support member 76 has a pair of upwardly extending arms 77 as shown in FIG. 4. A locking lever 78 is articulated on a pin 80 which is supported by the arms 77 of the support member 76. A suitable spring 81 on the pin 80 tensions the locking lever 78 in a clockwise direction as shown in FIGS. 5 and 6.

A small housing 82 is attached to the other half of the valve member 60 and to the plate 65 by means of the retaining screws 68. This support housing 82 has a flat compartment that is filled with a meltable metal 84 that melts at a suitable temperature. The metal is sealed within the housing 82 by a cover plate 85 which is also held in place by the retaining screws 68. An irregularly shaped latch 86 is hinged to the housing 82 with one end of the latch 86 rotatably supported near the fusible metal 84 and a tip 87 on the latch 86 is disposed within the fusible metal 84. One end of a spring 91 is attached to the latch 86, while the opposite end of the spring 91 is attached below one of the support tubes 70. The spring 91 acts on the bolt 86 in the illustration according to FIG. 5 in a counterclockwise direction.

Rigidly attached to the latch 86 is a small, approximately U-shaped portion 88 which has a locking foot 89 and a shorter cam foot 90, both of which cooperate with the end of the locking lever 78 to hold the valve member in the open position and out to release the open position.

The mode of operation of the exemplary embodiment according to FIGS. 1 to 7 will be described below. Assume that the container is empty and that the closure or lid 12 is separated from the base 10. The objects to be picked up are placed in the container and the lid 12 is applied to the lower part 10. The lid 12 is held in place by placing the tapes 36 over the top of the lid and hooking the ends of the tapes 36 into the notches 38 formed in the base 10. Assume that valve member 60 is in its open position shown in FIG. 6 and that fusible metal 84 is rigid. Under this condition, the valve member 60 is in its open

Position held by the fact that the end of the locking lever 78 rests on the side of the locking foot 89, as shown in FIG. 6.

The container is now placed in an autoclave or other sterilizer. When an autoclave is used, one or two vacuum phases are created inside the autoclave to draw contaminated air out of the container. Since the valve is open, the air inside the container is drawn out through the hole 50 in the bottom wall portion io 55. When steam or other sterilizing fluid is applied to the exterior of the container, this medium can flow freely inward into the interior of the container through opening 50. The high temperatures associated with the sterilization process melt the metal 84 after a predetermined time which is chosen such that the melting occurs some time after the container and its contents have been sterilized. This will preferably be at the end of the heating phase and before the final vacuum phase, which is typically used in an autoclave, to remove the steam from the autoclave. When the metal 84 melts, the resilience of the valve member 60, assisted by the force of the spring 75, moves the locking lever 78 against the locking foot 89 and pivots the latch 86 against the force of the weaker 25 spring 91. The tip 87 of the latch 86 can move move within the molten metal as this metal is no longer rigid. Since the U-shaped member 88 pivots with the latch 86, the cam foot 90 contacts the upper surface of the locking lever 78 and presses it down against the force of the spring 81 until the tip of the lever 78 at the lower edge of the locking foot 89 glided past. As soon as this happens, the valve member rapidly moves to the position shown in FIG. 5, in which the resilient wall 64 of the valve member 60 is sealed 35 against the wall surface 53. The locking lever 78 is pressed down under the lower end of the locking foot 89. The spring 91 presses the latch 86 into the position shown, in which the end of the locking lever 78 is touched by the end of the locking foot 89. The end of the locking foot 89 40 is chamfered, approximately at the angle of the direction of the locking lever 78 which it assumes in the closed position.

The container is now sealed with its contents sterilized so that the container can be removed from the sterile atmosphere. When the container and its contents are sterilized in an autoclave as described above, there is usually a further vacuum phase after the valve is closed. When the pressure surrounding the container in the autoclave becomes significantly less than 50 the pressure in the container, the atmosphere within the container can escape from it through the resilient seal 30. This is due to the shape of the flange surface 20 on the base 10 and the size and compliance of the lower end of the seal 30. Since the 55 relationship between the flexible wall 64 and the surface 53 is somewhat similar, it is possible that also in FIG a certain pressure equalization takes place in this area. This pressure equalization is also desirable because a certain amount of steam may be present inside the container, and it is preferable that the interior of the container is relatively dry.

When a strong vacuum is applied to the outside of the container, a vacuum is also created inside it. Then, when the pressure outside the container is brought to atmospheric pressure, there is a vacuum inside the container and neither the seal nor the valve allow gas to enter the container. The curved or curved design of the container is such

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met that its walls can withstand a relatively high pressure difference between the inside and the outside of the container. As a precautionary measure, however, it can be advisable in the case of larger containers to allow the handle 15 of the insert or the shell 14 to rest against the inner surface of the lid 12, as shown in FIG. 2, in order to additionally reinforce the container.

The container with its contents can now be brought to any place for storage and storage for future use, or it can be brought directly to where its contents are to be used. If the container is to be opened, it is first necessary to remove the existing vacuum in the container. To do this, it is only necessary to depress the valve lever 74, thereby opening the valve. The sound that accompanies the vacuum release indicates that the contents of the container are still sterile. On the other hand, if pressure equalization has already taken place and the vacuum inside the container no longer exists, the lack of noise warns the user who opens the container that the content can no longer be sterile. The compliant member 43 of the indicator 42 also indicates the condition of the interior of the container by being depressed when a vacuum exists and by being raised when there is no vacuum.

Due to the excellent sealing achieved by the seal 30, even if air molecules penetrate the container 30 after a long time, contaminating microorganisms cannot pass through the seal 30, since most microorganisms are much larger are as air molecules. In this way, the seal 30 acts as a filter, even if the vacuum in the container is eventually lost.

Shortly after the sterilization temperature begins to drop, the fusible metal 84 becomes rigid again and holds the locking foot 89 in the position shown in FIG. 6. Thus, when the valve is open, the tip of the lock lever 78 slides from the end of the lock foot 89 and is slightly clockwise urged by the coil spring 81 thereof and comes into engagement with the cam foot 90. When the lever 74 is released, the end of the Locking lever 78 again engages the side of locking foot 89 and holds the valve in the open position. In this way, depressing the lever 74 not only causes the vacuum within the container to be released, but at the same time causes the valve member to be tensioned in the open position, so that the container is again prepared for sterilization. This is very important because it does not require the operator to remember to open the valve before reinserting the container into the sterilizer. Thus, if the container is used to sterilize surgical instruments, for example, and if the container is brought directly into the operating room, the instruments can be removed directly from the container, used, washed if necessary and then put back into the container for sterilization.

If it is preferred not to bring the container directly into the operating room, the container can be opened immediately outside the operating room and only the sterile insert 14 with the instruments on it can be brought into the operating room. Here, too, the instruments can be put back into the insert 14 after use and this can be put back into the container for further sterilization. It is only necessary to put the cover 12 back on and to fix it in position and the container can then be reinserted into the autoclave for sterilization.

As a further modification of this method, the container can also be inserted into a (not shown) sterilization bag during the sterilization process. Such a pouch is available on the market and is described in US Pat. No. 3,595,465. The 5 containers could be placed in such a bag and inserted together with the bag into the autoclave. The bag is designed to allow steam to pass through it during the sterilization process, but it is sealed to a considerable extent during the sterilization process. With this type of use, the container could be removed from the bag just before it is brought into the operating room. In this way, the entire container would still be sufficiently sterile and the instruments could be removed directly from the lower part of the container. The top edge ls of the base would still be sterile, even in the event that an operator's hand should touch this area when removing instruments.

One of the advantages of the arrangement described above is that both the valve and the container are reusable. As another embodiment, a second example is illustrated in FIGS. 8 to 10, which shows a single-use, simplified valve, but which also uses the principle of the fuse. As shown in FIG. 8, a small annular projection 100 is formed in the wall 25 101 of a container similar to that of FIG. 1. One or more holes 102 are formed in the annular wall 100 to allow access to the container. An additional hole is formed in the center of the annular wall 100 and receives a disposable valve member 106 which is configured to control access to the container through the holes 102. The valve member 106 has a protrusion 108 formed in one piece therewith and which is rounded and dimensioned such that it can be pressed into the hole in the center 35 of the annular wall 100, as shown in FIG. 8. A peripheral shoulder 108a engages the inside of the container wall and holds the valve in place on the container.

The valve member 106 is made from a resilient, rubbery material that allows the protrusion 108 to be pushed into the hole in the container wall. The valve member 106 is formed in the shape shown in FIG. 9, which is substantially circular, the periphery of the valve member being bent upward in the manner of a pan and with its edge 45 closely abutting the outer surface of the annular wall 100 and the Closes valve openings 102 in the container. In this way, the valve is closed in the position shown in FIG. 9. This could be called the normal position, since this is the position that the rubber-like valve member 106 wishes to assume on its own. If a vacuum exists in the container, this helps to keep the valve member tight against the holes 102.

In order to keep the valve in its open position, a fuse 110 is provided 55 in the form of a ring of flat shape, similar to a washer. As shown in FIG. 10, valve member 106 has an inner slot 107 with a small diagonal slot 109, thereby forming two resilient tabs 112 and 114. After the valve member 60 106 is manufactured in the shape shown in FIG. 9, the fuse element is inserted into the slot 107 by depressing the outer periphery of the valve member 106 so that the lock washer is inserted through the slot 109 into the slot 107 can be. The locking washer 65 occupies only the outer part of the slot 107. When the locking washer is inserted in this way, the valve member 106 has the shape shown in FIG. 8 in which the outer periphery of the valve member is removed from the openings 102

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will hold. The valves are normally delivered in this form. In this way, a user of the container can simply take a valve of this type and snap it into the container in the position shown in Fig. 8. The container is then ready for sterilization.

At an appropriate time during the heating and sterilizing cycle, the lock washer 110 melts and allows the valve member 106 to assume its normal or originally formed shape, which is indicated in Fig. 10 by dashed lines. In this way, the valve is closed, as shown in FIG. 9. The closing movement of the valve member 106 together with the force of gravity causes the molten securing metal to flow towards the inner end of the slot 107 in the valve member 106, as shown in FIG. 9. If the locking metal solidifies again, it does not interfere with the sealing effect of the valve. Instead, it keeps the valve in the closed position to some extent.

When it is desired to release the vacuum within the container, a tab 118, which is integrally formed on one edge of the valve member 106, is withdrawn from the container so that the vacuum is released through the adjacent hole 102. The container lid can then be removed. The valve member 106 can also be removed by simply pulling the valve tab 118 a little harder. When the container is to be sterilized again, a new valve member 106 can be snapped into position quickly and easily. The new valve member can of course be used as soon as the old one is removed.

11, a generally cylindrical container is shown with a base 120 having a bottom wall 122 and an upwardly extending side wall 124. The upper part of the side wall has an inwardly extending shoulder 123, a retracted cylindrical part 125 and an outwardly extending flange 126 on the upper edge of the wall part 125.

Arranged beneath the flange 126 is a flexible seal 130 which is dimensioned such that it lies tightly against the cylindrical wall part 125. Seal 130 further includes an outward and downward resilient flange 131 which contacts the inner surface of an outward and downward side wall 132 of a lid 134 of the container. Like gasket 30 in Fig. 2, gasket 130 not only seals the lid from the base, but also acts as a one-way valve and allows gas to be drawn out of the container, but prevents gas from entering the container .

The bottom wall 122 of the container is drawn upward and a recess 121 is formed on one side of the bottom wall 122. A valve member 140 made of resilient, rubber-like material is in the recess

121 used. The valve member 140 is similar to the valve member 106 shown in FIG. 9 and it has an inwardly extending projection 142 which is rounded and sized so that it fits into a hole in the bottom wall

122 can be pressed. The valve member 140 is made with the shape shown in FIG. 12. Typically, this valve is circular in shape, with the outer periphery curved upward in a pan-like shape so that the valve member can closely contact the outer convex surface of the wall surrounding the same and thereby close the valve openings 144 leading into the container.

In order to keep the valve member 140 open, a band 146 is provided, which consists of known plastic material that shrinks when heated. The tape shrinks when it is heated to a certain temperature and then cooled again. One end of band 146 has one

Opening 147 that fits over an arrowhead-like end of a tab 148 that is integral with valve member 140. 11, band 146 extends around a portion of the edge of valve member 140 and holds that edge portion down and away from bottom wall 122 so that openings 144 in the container are not sealed. The inner end of the band 146 is connected to one end of a metal element or wire 150, the other end of which extends into the central core of the valve member 140, where it is attached to a fuse 152 arranged in the central core or the projection 142 is. The locking pin 152 is made of metal that melts at a desired temperature, in the special case after it has been exposed to the sterilizing temperature in an autoclave for a predetermined time. As explained above, the melting would occur around the end of the heating period and before the final vacuum phase, which is typically used in an autoclave, to remove the steam from the autoclave.

For use, valve member 140 can be supplied in the form shown in FIG. 13, in which it is tensioned and prepared for insertion into a container in the position shown in FIG. 11. However, valve member 140 is preferably supplied such that wire 150 is secured to locking pin 152 and strap 146 with the valve not yet tensioned. When the valve is to be used, it is tensioned by hooking the strap 146 over the tab 148 by sliding the hole 147 over the tab 148.

When the valve member is inserted in the position shown in Fig. 11, the container is ready to be used for a sterilization process. The container and its contents are placed in an autoclave or other sterilizing environment with the lid 134 closed. If steam now enters the autoclave, it can flow freely through the openings 144 in the bottom wall 122 into the container. After the desired sterilization temperature is reached, the fuse metal 152 melts, releasing the wire 150. The resilience of valve member 140 helps pull the wire out of the core of the valve member. The heat causes the band 146 to shrink or retract so that the wire 150 detached from the fusible metal 152 is quickly retracted over the edge of the valve member 140. In this way, the valve member becomes free and seals against the annular surface of the bottom wall 122 surrounding the holes 144, thereby blocking further flow of fluid through these openings into the container.

At the end of the sterilization process, the container cools down, the meltable metal contained in the valve plug solidifies and the inside of the container is sealed sterile. If a vacuum acts on the container exterior, the air under pressure in the container can escape between the sealing flange 131 and the wall 132 of the lid 134. Reverse flow into the container after removal of the vacuum is prevented, however, because pressure on the exterior of the container holds the sealing flange 131 against the wall 132. The strap 146 can now be removed from the tab 148 if desired.

If one wants to open the container, the vacuum in the container can be released by pulling on the tab 148 so that the adjacent edge of the valve member 140 is pulled off the container wall and air can enter the container. If desired, a filter, not shown, can be placed over the opening 144 and the protrusion 142 to filter the incoming air.

A stronger pull on the tab 148 causes the plug-like valve member 140 to completely come out of the container wall s

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is pulled out. If the container is to be used again, it is only necessary to insert a new valve member 140 into the container wall in the tensioned position according to FIG. 13, so that the container is ready for reuse in a sterilization process.

An advantage of this embodiment of the invention is that the valve can be returned to a service point for reprocessing or re-tensioning. Here, the old fusible metal is pulled out and a new wire 150, previously attached to a new locking pin 152, is inserted into the open end of the protrusion 142 and out through the side of the protrusion, the pin 152 in the protrusion 142 as in FIG 11 is arranged. The other end of the wire 150 is then attached to a new strap 146 and the strap can then be attached to the tab 148, either at the service point or by the user.

A particularly important property of the container according to FIG. 11 is that the cover 134 aligns itself with respect to the lower part 120. This means that the lid does not have to be placed perfectly on the base when the container is placed in an autoclave. The flange 126 formed at the upper end of the side wall 124 limits the downward movement of the lid at any point. During the last vacuum phase of the autoclave cycle, air and moisture within the container are drawn past the sealing flange 131, as explained above. When atmospheric pressure is then introduced into the autoclave, the sealing flange 131 and the valve member 140 prevent air from entering the container. In this way, the pressure difference between the inside and the outside of the container presses the lid 134 closer to the lower container part 120. Here, the flange 126 at the upper end of the side wall 124 limits the locking movement of the lid, so that the lid essentially aligns itself.

While in the three previously described exemplary embodiments the valve member in each case provides access to the interior of the container in order to introduce high-pressure steam into the container during the sterilization phase, another variant of the invention, not shown in the drawings, is that no valve member is used, but instead of which the container lid is kept open during the sterilization phase in order to allow the steam to enter the interior of the container.

In particular, the lid is aligned above the lower part of the container, but the lid and lower part are sufficiently distant from one another so that the seal in between does not have a sealing effect. In one embodiment, a support member made of temperature-dependent melting material is used to hold part of the lid somewhat away from the lower part. If desired, two or more such support members can be used to keep the entire lid slightly spaced from the base. Tether straps corresponding to straps 36 in FIG. 1

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and 2 or other suitable means can be used to create a closing force between the lid and base in addition to gravity. The support parts are designed in such a way that they soften or buckle at the desired time during the sterilization cycle, with the result that the lid falls down by gravity and is additionally pressed into the sealing position by the holding straps. The formation of the seals and the lid as described above provides a good seal in this way, although one side of the lid can initially be depressed more than the other. This is because a tighter seal is achieved when atmospheric pressure acts on the outside of the container.

In the description of the exemplary embodiments of the invention, reference is made several times to the sterilization cycle of an autoclave. While a certain number of different autoclave phases are conventionally used, a typical example of this is shown in Fig. 14 to provide a better understanding of the invention. As shown in FIG. 14, a pre-vacuum phase I is first used to remove contaminated air from the inside of the autoclave. Since the containers of the type described above have open valves or other access options when the container is inserted in the autoclave, the vacuum naturally also acts on the interior of the container. After the pre-vacuum phase I, normal pressure and ambient conditions are restored due to the introduction of pure, filtered air. A second pre-vacuum phase II also ensures that only a minimal amount of non-sterilized air remains inside the autoclave. Many smaller autoclaves only use a single pre-vacuum phase.

In phase III of the process, steam is added at high temperature and pressure to create the sterilizing environment. The steam used for sterilization enters the interior of the container through the valve member or through other access openings. The various fuses described above are selected so that they melt or soften towards the end of the high temperature phase. This means that the material softens when steam is steamed, but the steam takes a certain time at this temperature to melt or soften the fuse material.

A vacuum phase IV is then applied. Although the lid and valve are closed during this phase, steam and condensing moisture are withdrawn from the container through the seal as described above. Since this phase typically lasts about twenty minutes, there is enough time to adequately dry the contents of the container.

During phase V of the cycle, atmospheric pressure is again introduced into the autoclave. Since this atmospheric pressure cannot penetrate into the sealed container, the atmospheric pressure acting on the container presses the container lid more strongly onto the lower part, because of the formation of the lid, the lower part and the intermediate seal.

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5 sheets of drawings

Claims (11)

621 066 2nd PATENT CLAIMS 1. A method for sterilizing objects, in particular surgical instruments, in which method the objects are accommodated in a container (10, 12) and in which the container is sterilized from the outside thereof, the outside with the inside of the Container at least until sterility is reached, characterized in that the sterilizing action is interrupted, that the pressure on the outside of the container is reduced and that the sterile container using automatically acting means (58, 106, 140) is sealed, wherein these agents can be influenced by the sterilizing action on the container, namely before the container is exposed to the non-sterile environment. 2. The method according to claim 1, characterized in that the sterilizing action is achieved by increasing the temperature and that the sealing comprises such a closing of the container by temperature-responsive means that a flow directed into the container is prevented, but that after outward flow is possible if the pressure inside the container is greater than in its surroundings. 3. The method according to claim 2, characterized in that the container is closed at a temperature which is above that which prevails during the final phase of the working cycle of a vacuum autoclave. 4. The method according to claim 2, characterized in that the container is subjected to a negative pressure before the sterilizing action takes place, that the sterilizing action is achieved by pressurized steam, that vacuum is then formed to remove the steam that the container during the supply of steam is open, but it is closed before the vacuum has fully formed. 5. Apparatus for carrying out the method according to claim 1, with a container (10, 12) and with means (58, 106, 140) to enable access to the interior of the container, characterized by means (84, 110, 150, 146) which act on the sterilizing Address action that affects both inside and around the container and that close the access means of the container after its contents have been sterilized to prevent anything from entering the interior of the container and through Pressure responsive means (30 or 58,106,140) that allow fluid to escape from the container if the pressure of the fluid in the container is greater than the pressure outside the container. 6. The device according to claim 5, characterized in that the means responsive to the sterilizing action include a temperature-responsive valve (58,106,140) which closes automatically when the objects have been exposed to the sterilizing temperature for long enough, and in that Valve is a check valve. 7. The device according to claim 5, wherein the container has a lower part (10) and a lid (12), wherein between the lower part (10) and the lid (12) there is a flexible seal (30), characterized in that the resilient seal is designed to prevent fluid from flowing into the container but to allow fluid to flow out of the container if the pressure inside the container is greater than the external pressure. 8. The device according to claim 7, characterized in that the cover (12) has a depending flange (28) which fits over part of the lower part, and that the seal extends between the flange and the lower part, the seal having a free one End portion that acts as a check valve. 9. The device according to claim 5, with a valve opening (50, 108a, 144) in the container, a resilient valve member (64, 106, 140) and with means (68,108,142) for fastening the valve member on the container, characterized by temperature-responsive means (84, 110, 152), which are carried by the valve member, which hold the valve member in an open position with respect to the valve opening below a predetermined temperature and which trigger the valve member at a predetermined temperature and permit its closure. 10. The device according to claim 9, characterized in that the valve member has a projection (108, 142) which fits into an opening in the container, and represents the means for fastening the valve to the container and that the valve member has a surface facing the projection that is adapted to the container to close the valve opening. 11. The device according to claim 10, characterized in that the holding means comprise a shrinkable band (146) which is connected between the temperature-responsive means and part of the valve member to hold the valve member in the open position, the band shrinking, as soon as the temperature-responsive agents take effect.