Abstract:
The invention relates to a sterile container, especially for receiving and storing surgical instruments or material in sterile conditions, comprising and receiving area formed by a container bottom and container walls, a lid for sealing the receiving area, and a gas exchange opening which can be sealed by a sterile filter. In order to enable the sterile filter to be replaced in a simple manner, a filter unit is provided, comprising the sterile filter, a support and a holding element, the sterile filter is maintained between the support and the holding element and the filter unit is mounted on the lid and/or bottom of the container.

Description:
[0001]    The present disclosure relates to the subject matter disclosed in international application PCT/EP02/12670 of Nov. 13, 2002, which is incorporated herein by reference in its entirety and for all purposes. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The invention relates to a sterile container, in particular for the holding and sterile storage of surgical instruments or material, comprising a holding space, which is defined by a container base and container walls, a lid for closing the holding space and a gas exchange opening, which can be closed off by a sterile filter.  
           [0003]    Sterile containers of this type are, for example, loaded with surgical instruments or material and sterilized in a sterilizer. A sterile filter is required in order to prevent germs from penetrating into the container. The sterile filter has to be replaced from time to time, which in previously known sterile containers has only been possible in laborious manner.  
           [0004]    Therefore, it is an object of the present invention to improve a sterile container of the type described in the introduction in such a way that the sterile filter is easy to exchange.  
         SUMMARY OF THE INVENTION  
         [0005]    In a sterile container of the type described in the introduction, this object is achieved, according to the invention, by virtue of the fact that there is a filter unit, which comprises the sterile filter, a carrier and a holding element, that the sterile filter is held between the carrier and the holding element, and that the filter unit is mounted on the lid and/or on the container base.  
           [0006]    To exchange the sterile filter, it is sufficient to release the complete filter unit from the lid or from the container base and exchange it. There is no longer any need to grip the sterile filter itself, which on the one hand helps to avoid damage to it and on the other hand prevents soiling.  
           [0007]    In a preferred embodiment of the invention, it is possible to provide that the filter unit is configured in the form of a single-part filter cartridge, and that the carrier, the sterile filter, and the holding element are nonreleasably connected to one another. This allows the filter unit to be exchanged as a whole, making filter exchange a quicker operation. At the same time, the sterile filter can be permanently mounted and protected in the filter cartridge. Furthermore, the leaktightness of the filter cartridge can be tested even during production. This is not always ensured in the case of a manually assembled filter unit.  
           [0008]    To securely hold the sterile filter, it is advantageously provided that the carrier has at least one carrier support for supporting the sterile filter, and at least one carrier aperture which adjoins the carrier support. While the carrier support on the one hand stabilizes the sterile filter of the filter unit, the carrier aperture allows sufficient gas exchange through the sterile filter.  
           [0009]    To protect the sterile filter from mechanical loads, in particular to protect it from damage from instruments and tools acting in or on the sterile container, there is preferably at least one carrier aperture cover which covers the at least one carrier aperture at a spacing therefrom.  
           [0010]    It may be advantageous if the filter unit is mounted moveably, if the filter unit, in a closed position, closes a flow path and, in a flow-permitting position, opens the flow path, so that gas exchange in the closed position is possible only through the sterile filter and in the flow-permitting position is possible through the sterile filter and/or through the flow channel. The moveable mounting allows gas exchange to be additionally controlled and/or regulated. In particular if relatively high levels of gas exchange are required, the filter unit can be transferred into the flow-permitting position and an additional flow path can be opened up.  
           [0011]    To allow the objects stored in the sterile container to be stored in the complete absence of germs, the filter unit, in the closed position, is held on the sterile container under prestress.  
           [0012]    It is expedient if there is a sealing element for mounting the filter unit in a gastight manner. This sealing element allows the filter unit to be completely sealed on the sterile container.  
           [0013]    It is particularly expedient if the sealing element comprises a sealing ring mounted on the holding element. Sealing rings are particularly simple to produce and are also simple to fit to the holding element or another element of the filter unit.  
           [0014]    According to a preferred embodiment of the invention, it is advantageous if there is a pressure-relief valve, if the pressure-relief valve is disposed in such a way that in a basic position it adopts a closed position and that it adopts a flow-permitting position when a pressure in the vicinity of the sterile container exceeds a pressure in the sterile container by a predetermined pressure difference. This makes it possible to avoid damage to the sterile container, since, before the sterile container can be deformed as a result of a particularly high pressure in the surrounding region or a correspondingly high pressure gradient, the pressure-relief valve opens, allowing gas to flow into the container.  
           [0015]    To reduce the number of components required, it is advantageous if the filter unit forms the pressure-relief valve. The filter unit therefore performs two functions; firstly it serves to block germs, and secondly it serves as a pressure-relief valve.  
           [0016]    It is particularly expedient if the filter unit is mounted on an inner side of the lid. This creates additional space in the container. Moreover, it is also possible to exchange a filter unit by exchanging a complete lid. Mounting on the inner side of the lid offers additional protection for the filter unit with respect to mechanical load or damage.  
           [0017]    To additionally protect the filter unit against mechanical damage, it may be advantageous to provide a protective element which covers the filter unit at a spacing therefrom.  
           [0018]    It is advantageous if the protective element is disposed on an outer side of the lid. This means that the sterile filter is securely mounted between the protective element and the carrier.  
           [0019]    To achieve simple assembly or to allow simple access to the filter unit, it is possible to provide that the protective element can be connected to the lid by means of a snap-action or latching connection.  
           [0020]    To avoid further openings at the lid, it is advantageous if the protective element can be latched to an inner rim of the gas exchange opening. The gas exchange opening is in any event required in order to allow gas exchange with the interior of the sterile container.  
           [0021]    A particularly simple latching connection results if the protective element comprises elastic spring arms which protrude toward the sterile container and are provided with a latching projection. Apart from the spring arms, there is no need for any moveable parts for fixing the protective element to the sterile container.  
           [0022]    It is advantageously possible for there to be between the protective element and the lid at least one opening for the passage of gas, which is in fluid communication with the gas exchange opening and is disposed in such a way that gas flow is made possible in a direction of flow running substantially transversely with respect to the flow-permitting direction of the sterile filter. Gas exchange from the region surrounding the sterile container to the gas exchange opening can be achieved via the opening for the passage of gas, which is necessary in particular if the protective element is disposed on the lid.  
           [0023]    To prevent liquid from penetrating into the filter unit, it is expedient if there is an inflow edge, which is disposed on the outer side of the lid, faces away from the gas exchange opening and slopes downward toward the outside relative to a lid plane. If liquid reaches the lid, the inclination of the inflow edge means that it can flow away from the gas exchange opening and therefore cannot reach the filter unit.  
           [0024]    Preferably, the lid has at least one spacer element for stacking a further sterile container on the sterile container, so that gas exchange through the gas exchange opening is possible with stacked sterile containers. On the one hand, therefore, this allows gas exchange, and on the other hand the gas exchange opening and the sterile filter covering it are also protected from further sterile containers placed on top of them.  
           [0025]    According to a preferred embodiment of the invention, it is possible to provide for the sterile filter to be a long-term filter, in particular made from polytetrafluoroethylene (PTFE). This makes it possible to extend the intervals between maintenance on the sterile container. It is only seldom necessary to exchange the filter unit.  
           [0026]    The sterile container becomes particularly expedient and simple to produce if the lid is made from a plastic, in particular from polyether ether ketone (PEEK) or polyphenylene sulfone (PPSU). 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    The following description of a preferred embodiment of the invention, in conjunction with the drawing, serves to provide a more detailed explanation. In the drawing:  
         [0028]    [0028]FIG. 1 shows a perspective overall view of a sterile container;  
         [0029]    [0029]FIG. 2 shows a plan view of an excerpt of a sterile container;  
         [0030]    [0030]FIG. 3 shows an exploded view of an excerpt of a lid of the sterile container;  
         [0031]    [0031]FIG. 4 shows a partially cut-away cross-sectional view through an excerpt of a lid;  
         [0032]    [0032]FIG. 5 shows a partially cut-away side view of an excerpt of a lid;  
         [0033]    [0033]FIG. 6 shows an enlarged, perspective partial view of a lid;  
         [0034]    [0034]FIG. 7 shows a plan view onto the underside of half of a lid;  
         [0035]    [0035]FIG. 8 shows a cross-sectional view of an excerpt of a filter cartridge which is mounted in a gastight manner on the lid; and  
         [0036]    [0036]FIG. 9 shows a cross-sectional view of an excerpt similar to that shown in FIG. 8, with a filter cartridge lifted off. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]    [0037]FIG. 1 illustrates a sterile container, which is denoted overall by reference numeral  10  and comprises a substantially tub-like, cuboidal container  12  for holding, for example, surgical instruments or material, and a lid  14 . Pivotably mounted carry handles  16  are disposed at the end faces of the container  12 .  
         [0038]    The structure of the lid  14  is explained in more detail with reference to FIGS.  2  to  9 .  
         [0039]    The lid  14  is provided with an encircling rim  18  which projects perpendicularly from a lid plane  15 , so that the lid  14  completely covers and partially engages around the container  12 . A sealing rim  20 , between which and the rim  18  a seal (not shown) can be inserted, runs parallel to and at a spacing from the rim  18 . When the lid  14  has been fitted, the sealing rim  20  is located inside the container  12 . The seal makes it possible to produce a gastight connection between the lid  14  and the container  12 .  
         [0040]    At its narrow end sides, the lid  14  in each case has a bearing bracket  22 , on which a resilient closure flap  24  can pivot about a pivot axis running parallel to a pivot axis of the carry handle  16  when the lid  14  is seated on the container  12 .  
         [0041]    The lid  14  has two symmetrically disposed circular openings  26 , which have an opening rim  28  which faces parallel to the lid plane  15  and on which four webs  30 , which run perpendicularly toward one another and meet in the center of the opening  26 , for stiffening the lid, are disposed symmetrically. Between each pair of webs  30  disposed at the opening rim  28 , two indentations  32  and  33  are cut symmetrically into the opening rim  28 .  
         [0042]    The opening  26  is surrounded by an annular surface  34 , which runs parallel to the lid plane  15  but is set back toward an underside  36  of the lid. As a result, an inner annular edge  38  is formed on a top side  37  of the lid and an outer annular edge  39  is formed on the underside  36  of the lid. The annular edge  38  is alternatively adjoined by in each case four inflow edges  40  and four support surfaces  42 . The inflow edges  40  are curved concavely away from the lid top side  37  and are inclined outward, so that an inclined plane with an angle of inclination  44  between the inflow edge  40  and the lid plane  15  of approximately 2° is formed.  
         [0043]    The support surfaces  42  run parallel to the lid plane  15  and, when seen in plan view, are approximately in the shape of a trapezoid, but in each case with concavely curved base edges. The longer of the two base lines of the support surface  42  is adjoined by a three-sided pyramid  46 , which has a base area which is substantially in the shape of an isosceles right-angled triangle. An apex  48  of the pyramid lies just above the base sides, which intersect at right angles, of the base surface, slightly offset toward the opening  26 .  
         [0044]    This results in the formation of a run-off surface  50  which is approximately in the shape of an isosceles, right-angled triangle which is inclined toward the support surface  42 . The support surface  42  is offset away from the lid top side  37 , parallel to the lid plane  15 .  
         [0045]    The overall result, therefore, is an approximately square structure on the lid  14 , which is formed by four pyramids  46 , which are each seated in the corners of the square, the side faces of the square running parallel to sides of the lid  14 . The inflow edges  40  are therefore inclined perpendicularly toward the sides of the lid  14 . The structure has a total of two planes of symmetry running parallel to the sides of the lid  14 . On its side facing away from the opening  26 , the inflow edge  40  extends down to the level of the lid plane  15 . When the lid is seen from the side, therefore, the result is approximately a concave shape, facing away from the lid top side  37 , from the apex  48  of the pyramid  46  in a corner of the square structure to the apex  48  of the pyramid  46  in an adjacent corner of the structure.  
         [0046]    Adjacent to the indentations  32  and  33  are disposed a total of four hollow-cylindrical, open sleeves  52  protruding from the underside  36  of the lid. A filter cartridge  54  is mounted resiliently on these sleeves. The filter cartridge comprises an approximately octagonal filter holder  58 , which is provided with a carrier rim  56  and has an annular filter receiver  60  for accommodating a circular long-term filter  62 . An annular recess  64 , which is configured with a larger diameter than the filter receiver  60 , is used to accommodate a holding ring  66 , which in cross-section has an L-shaped profile, one limb of which presses the long-term filter  62  into the filter receiver  60  and the other limb of which engages against the recess  64 . The holding ring  66  is provided with an annular ring groove, which in cross-section includes slightly more than half of a circle, for accommodating a sealing ring  70 .  
         [0047]    Four mounting sleeves  74 , corresponding to the sleeves  52  disposed on the lid  14 , protrude from a filter holder base  72  toward the lid; these mounting sleeves are open from the filter holder base  72 , and their other, closed end face  76  is provided with a central through opening  78  whose diameter corresponds to that of the sleeve  52 . To mount the filter cartridge  54 , the four mounting sleeves  74  are pushed over the sleeves  52 , a coil spring  80  is in each case fitted over the sleeves  52 , and then the mounting sleeves  74  are closed off by the filter holder base  72  with a stopper  82  which has a disk-like head  84  whose external diameter is matched to the internal diameter of the mounting sleeves  74 . On account of the fact that the coil spring  80  is supported against the head  84  of the stopper  82 , it presses the end face  76  onto the underside  36  of the lid.  
         [0048]    The filter holder base  72  is provided with a total of twenty strip-like slots  86  of different lengths, with in each case five slots running parallel to one another and approximately covering the area of a quarter-circle. Slots  86  belonging to adjacent quarter-circles are in each case positioned perpendicular to one another. A protective web  88  is formed between each pair of slots  86 . A strip  90 , which faces away from the filter holder base  72  and from which, once again running parallel to the filter holder base  72 , there protrudes a support web  92  facing away from the associated protective web  88  and in each case completely covering a slot  86 , is disposed on each protective web  88 . All the support webs  92  define a common plane on which the long-term filter  62  rests. Overall, the filter receiver  60  and the support webs  92  form a carrier support for supporting the long-term filter  62 .  
         [0049]    The filter holder  58 , the long-term filter  62  and the holding ring  66  are fixedly connected to one another, for example by welding or adhesive bonding. In the assembled state, the coil springs  88  press the filter cartridge  54  onto the underside  36  of the lid, with the filter cartridge  54  being sealed against the underside  36  of the lid by means of the sealing ring  70 .  
         [0050]    The holding ring  66  has an outer ring and an inner ring  94  running concentrically therewith, from which four holding ring webs  96  disposed radially and symmetrically stabilize the holding ring  66 .  
         [0051]    On account of the offset arrangement of support web  92  and protective web  88 , the long-term filter  62  supported on the support webs  92  is protected from direct mechanical damage. However, the long-term filter  62  is virtually unprotected on its side facing toward the opening  26 . For this purpose, a protective cover  98 , which is of mirror-symmetrical configuration and has a cover surface  100  curved convexly away from the top side  37  of the cover, is provided as a protective element; when the cover surface  100  is seen in plan view, it is in the shape of a non-equilateral octagon with short sides  102  and long sides  104 .  
         [0052]    An annular strip  108 , which comprises four cutouts  110 , each disposed diametrically in pairs, protrudes from an underside  106  of the protective cover. These cutouts  110  are shaped in such a manner that they can engage over the webs  30  and the protective cover  98  rests on the webs  30 . Two spacer strips  112 , which cross one another, are disposed on the underside  106  of the protective cover, as additional spacers, which spacer strips, in the region of the cutouts  110 , project outward beyond the ring strip  108  as far as the long sides  104 . When the protective cover  98  has been fitted, these strips rest on the annular surface  34 .  
         [0053]    To secure the protective cover  98  there are four latching connectors  114 , which each comprise three limbs, which are disposed at right angles to one another, form a U-shaped frame  116  and two of which protrude radially outward from the ring strip  108 . As free ends of the spacer strips  112 , they form spacers resting on the annular surface  34 . From a transverse web  118  of the frame  116 , two latching arms  120  protrude parallel and at right angles from the underside  106  of the protective cover, which latching arms are provided at their free ends with a latching lug  122  protruding at right angles. The four latching connectors  114  are disposed in diametrically opposite pairs on the protective cover  98 .  
         [0054]    To secure the protective cover  98 , the latter is moved perpendicularly toward the top side  37  of the lid and is oriented in such a way that the cutouts  110  each face toward a web  30  and the latching arms  120  each slide into one of the two indentations  32  and  33 . As soon as the cutouts  110  rest on the webs  30 , the closure strips  112  and the frames  116  rest on the annular surface  34 , the latching arms  120  latch to the opening rim  28  as a result of the latching lugs  122  engaging behind the opening rim  28 .  
         [0055]    The size of the protective cover  98  is selected to be such that in the inserted position the annular surface  34  is completely covered. The short sides  102  then rest on the support surfaces  42 , while the long sides  104  run parallel to the side edges of the lid  14  and in each case partially cover the inflow edges  40 . When the protective cover  98  is inserted, the long-term filter  62  held in the filter cartridge  54  is also completely protected from mechanical damage from its other side.  
         [0056]    In an alternative variant of a lid, which is indicated by dot-dashed lines in FIG. 2, the long sides  104  of the protective cover  98  are lengthened. The pyramid  46  then has, in its run-off surface  50 , an additional recess, in which the short side  102  of the protective cover  98  is fitted. This results in a seamless transition between the run-off surface  50  and the cover surface  100 .  
         [0057]    The highest point of the protective cover  98  when the latter is inserted lies beneath the highest point of the four pyramids  46 , so that when sterile containers  10  are stacked on top of one another the container  12  which is mounted on the lid  14  rests only on the apexes  48  of the pyramids  46  but does not touch the protective covers  98 .  
         [0058]    If, with a substantially horizontally mounted sterile container  10 , liquid reaches the top side  37  of the lid, for example reaches the protective cover  98 , the curvature of the protective cover  98  means that the liquid can flow off to the short or long sides  102  or  104 , respectively. From the long sides  104 , the liquid passes onto the inflow edges  40 , from which the liquid can flow off to the sides of the lid  14  on account of the inclination of these edges.  
         [0059]    When the protective cover  98  is fitted, a substantially double-convex lens-shaped inflow opening  124 , as seen in side view, is formed, through which a gaseous fluid can flow in and out. The fluid then flows substantially parallel to the lid plane  15 , through the opening  26  substantially perpendicular thereto. In a basic position illustrated in FIG. 8, the filter cartridge  54  engages against the underside  36  of the lid, sealed off by means of the sealing ring  70 . If the sterile container  10  is exposed to hot steam, the latter flows to the long-term filter  62 , as described above. It passes through the long-term filter  62  and then follows a flow channel, defined by the support web  92 , the strip  90  and the protective web  88 , into the interior of the container  12 .  
         [0060]    If a pressure acting outside on the sterile container  10  exceeds a force which can be set by means of the coil springs  80 , the filter cartridge  54 , which is mounted resiliently on the lid  14 , acts as a pressure-relief valve. The filter cartridge  54  is lifted off the underside  36  of the lid and opens up a flow channel  126  which is closed in the basic position, as illustrated in FIG. 9. Hot steam can now pass not only through the long-term filter  62  but also into the interior of the container  12  via the flow channel  126 . As soon as the pressure gradient drops again, the coil springs  80  press the filter cartridge  54  back onto the underside of the lid, so that steam or gas can only flow in and out via the long-term filter  62 . FIGS. 8 and 9 use arrows to indicate the incoming and outgoing flow of a gas or steam.  
         [0061]    The container  12  may optionally made from metal or plastic. The lid  14  is preferably made completely from a plastic, for example from polyether ether ketone or polyphenylene sulfone. The long-term filter is preferably made from polytetrafluorethylene.