GB2188549A

GB2188549A - Instrument sterilization container

Info

Publication number: GB2188549A
Application number: GB08705250A
Authority: GB
Inventors: Kenneth V Pepper
Original assignee: Bemis Manufacturing Co
Current assignee: Bemis Manufacturing Co
Priority date: 1986-04-07
Filing date: 1987-03-06
Publication date: 1987-10-07
Anticipated expiration: 2007-03-06
Also published as: GB2188549B; SE501170C2; AU6973087A; GB8705250D0; JPS62266061A; SE8701102D0; DK168424B1; NO871389L; FR2596652B1; CA1271017A; JPH0822309B2; DE3711621C2; BE1001375A3; ES2005128A6; NL8700768A; NO871389D0; NL193209B; AU597943B2; DE3711621A1; NO169697C

Description

SPECIFICATION Instrument sterilization container Background ofthe invention The invention relates to apparatus for containing items such as hospital instruments during sterilization and for storing the items after sterilization.

It is knawn to sterilize hospital instruments in an autoclave by subjecting the instruments to one or more vacuum1steam cycles. Afterthe desired number of vacuum/steam cycles, a vacuum is drawn to expedite evaporation of moisture or condensation remaining on the instruments.

It is also known to place the instruments in a container during this sterilization process. Typically these containers are made of metal and include openings permitting vacuums two be drawn in the containers and steam to enterthe containers. The openings are covered with filters that prevent the entry of contaminants into the containers, and the filters are typically made of cotton, cellulose, or other absorbent materials. These filters must be replaced after each sterilization cycle.

Water drainage is mostly unnecessary with metal containers because metal containers conduct heat rapidly and therefore facilitate evaporation of condensation. Some metal containers have flat bottom walls including openings and filters such as described above. While these filters may permitwaterto pass through, they generally absorb any water that reaches them. Some metal containers have in their bottom walls tem- perature-sensitive valves which permit water drainage until the temperature of the container drops below a certain point. These valves are subject to failure, they have complicated constructions, and one cannot see whether they have closed without opening the container and exposing the contents.

Recently, plastic containers have become popular because they can be made transparent, so their contents are visible, because they are not as hard as metal containers, so they do not damage sharp instruments, and because they conduct heat slowly, so they are easierto handle. However, slow heat conduction also has a disadvantage in that condensation does not evaporate as quickly as it does in a metal container. In plastic containers, condensation can pool and cool and adjacent plastic. Since plastic conducts heat slowly, the heat lost is not quickly replaced, and the condensation may not evaporate.

In other arts, it is known to use filters made of ceramic material, and more particularly of ceramic particles sintered togetherwith a glass binder, forfiltering liquids orfor diffusing air into liquids such as in an aquarium.

Attention is directed to the following U.S. Patents which disclose sterilization containers: Hohmann 4,400,357 Aug. 23,1983 Sanderson 4,372,921 Feb.8,1983 Sanderson 4,349,118 Sep.14,1982 Sanderson 4,196,166 Apr.1,1980 Huber 3,482,930 Dec. 9, 1969 Muir 1,576,535 Mar.16,1926 Attention is also directed to the following foreign patents:: British 353,832 British 20,992 German 1,492,374 French 39,836 Summary ofthe invention The invention provides an apparatus for containing items during sterilization and for storing the items after sterilization,the apparatus comprising a container including a bottom wall sloping downwardly toward a drain opening, and porous means located adjacent the drain opening for permitting the drainage of water from the container through the drain opening and for preventing the entry of bacteria into the container through the drain opening in the absence of water drainage. The invention is especially suited to plastic containers and provides a means for draining water from such containers.

In the preferred embodiment, the draining means includes a permanent or reuseable element which is water permeable and nonabsorbent and which is substantially impervious to bacteria when dry. Therefore, the element permits waterto pass through and drain out of the container and also, when dry, prevents bacteria from entering the container.

Preferably, the element t'as not more than one micron of permeability in air, and it has a thickness of not less than 3116 inch. As a result, the element creates a tortuous path for airborne bacteria and suhstantially prevents bacteria from passing through it. In the preferred embodiment, the element is made of nonabsorbent particles sintered togetherwith a glass binder. More particularly, the element is made of permeable ceramic material, and, still more particularly, of ceramic particles sintered together with a glass binder. The element is robust and has excellent chemical resistance that parallels that of glass,thus being resistant to corrosion and conditions of steam sterilization.

In the preferred embodiment, the bottom wall of the container includes a recess having therein a plurality of drain openings, the bottom wall slopes downwardly toward the recess, and the element is located in the recess. More particularly, both the recess and the element are circular, and the apparatus further comprises an annular gasket located between the element and the bottom wall, and means for securing the element in the recess to trap the gasket between the element and the bottom wall. This provides a substantially airtight and watertight seal between the element and the bottom wall so that water exiting the container and air entering the container must pass through the element.

Other features and advantages of the invention will become apparent to those skilled in the art upon review ofthefollowing detailed description, claims, and drawings.

Description ofthe drawings Figure 1 is a vertical cross-sectional view of an apparatus which embodies various of the features ofthe invention and which includes a container having a lid and containing an instrumenttray.

Figure2 is a top view of the container with the lid and instrument tray removed.

Before one embodiment of the invention is explained in detail, it isto be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and shoud not be regarded as limiting.

Description of the preferred embodiment An apparatus 10 for containing items during sterilization and for storing the items after sterilization, which apparatus 10 embodies various of the features of the invention, is illustrated in the drawings. As bestshown in Figure 1,the apparatus lOcomprises a container 12 having an interior and including a base 14 having an open upper end and a lower end. Preferably, the container 12 is made of a transparent plastic such as,for example, polysulfone plastic resin. The container 12 can be made of other suitable materials. The lower end of the base 14 includes a bottom wall 16 including a downwardly extending recess 18 having therein a plurality of drain openings20, and the bottom wall 16 slopes downwardly toward the recess 18.In the preferred embodiment the bottom wall 16 slopes downwardly at an angle of not less than 4.5 degrees. In the illustrated construction, the recess 18 is generally circular, and the base 14 also includes a plurality of inwardly extending ribs 21, the reason forwhich is explained hereinafter.

In alternative embodiments, the bottom wall 16 can include a plurality of recesses 18 each having therein drain openings 20.

The container 12 also includes a lid 22 securable on the open upper end ofthe base 14. The lid 22 can be secured to the base 14 by any suitable means (notshown). In the illustrated construction, the lid 22 includes, around its periphery, a downwardly opening groove 24 which receives the upper edge of the base 14. A gasket or seal 26 is located between the lid 22 and the upper edge of the base 1 4for sealing the lid 22 to the base 14. The lid 22 also includes a plurality of openings 28for permitting steam to enter the container 12 and for permitting a vacuum to be drawn in the container 12. In the preferred embodiment, the lid 22further includes an annular, downwardly extending boss 30 surrounding the openings 28, and a perforated, circular supporting frame 32 mounted on the boss 30.The supporting frame 32 supports, on its upper surface, a sheet 34 offilter material for permitting steam to enterthe container 12,for permitting a vacuum to be drawn in the container 12, and for preventing contaminants from entering the container 12. While the filter material can be any suitable material, in the preferred embodiment, it is a polyolefin fiber fabric. This filter material must be replaced after each use.

The apparatus 10 also comprises a perforated tray 36 removably located in the container 12 for supporting the items to be sterilized and stored. Preferably, the tray 36 sits on the above-mentioned ribs 21 insidethe base 14. In the illustrated construction, the tray 36 includes a plurality of openings 38 in its lower wall. The openings 38 permit condensation to drain from the items being sterilized.

The apparatus 10 further comprises porous means located adjacent the drain openings 20 for permitting the drainage ofwaterfrom the container 12 through the drain openings 20 and for preventing the entry of bacteria into the container 12 through the drain openings 20 in the absence of water drainage. Whilevarious suitable porous means can be employed, in the preferred embodiment, this means includes an element 40 which is water permeable and nonabsorbent and which is substantially impervious to bacteria when dry.

Preferably, the element 40 is "permanent" or reuseable and is made of permeable ceramic material, and, more particularly, of controlled size ceramic particles sintered together with a glass binder. In the preferred embodiments, the controlled size particles are particles of silicon carbide. Furthermore, in the preferred embodiment, the element 40 has not morethan one micron permeability in air and has a thickness of not less than 3/16 inch, so that the element 40 creates a tortuous path for airborne bacteria. It is known that such a tortuous path substantially prevents the passage of bacteria. A suitable element known as "Permeable Ceramic Material" is available from Ferro Refractories Division in Rochester, New York.

The element 40 is sturdy and highly resistant to damage, and it has excellent chemical resistancethat parallels that ofglass, so that it is resistant to corrosion, oxidation, and other conditions of steam sterilization.

In alternative embodiments, the element 40 can be made of any suitable nonabsorbent particles, such as stainless steel particles sintered together with a glass binder. However, it has been found that ceramic part Ides are preferable to stainless steel particles because stainless steel particles tend to oxidize with prolonged use.

In the preferred embodiment,the element 40 is generally circular, and the element 40 is located in the recess 18 and thus interiorly ofthe container 12. in alternative embodiments, the bottom wall 16 need not include a recess, and the drain openings 20 can be located in the bottom wall 16withthe element 40 located on the bottom wall 16 adjacentthe drain openings.

The apparatus 10 preferably further comprises an annular gasket 42 located between the element 40 and the bottom wall 16, and means for securing the element 40 in the recess 18 to trap the gasket 42 between the element 40 and the bottom wall 16. In the illustrated construction, the gasket 42 has a generally L-shaped cross-section and is actually trapped between the element 40 and both the bottom wall 16 and the sidewall of the recess 18. While various suitable means can be employed for securing the element 40 in the recess, in the preferred embodiment, such means includes a conventional fastening device 44 extending through the bottom wall 16 and the element 40. This device is preferably made of stainless steel.In the illustrated construction, an O-ring 46 is located around the fastening device 44 and between the bottom wall 16 and the element 40 for preventing water leakage and air passage between the fastening device 44 and the element 40.

During a sterilization process, the openings 28 in the lid 22 permit a vacuum to be drawn in the container 12 and permit steam to enterthe container 12. Items to be sterilized are supported on the tray 36, and condensation from the items passes through the openings 38 in the lowerwall ofthe tray 36 onto the bottom wall 16Of the base 14. Because the bottom wall 16 is sloped downwardly toward the recess 18, water collecting on the bottom wall 16 runs downwardly into the recess 18 and passesthroughthe element 40 and out the drain openings 20. When the process is over and the apparatus 10 is finally dry, the element 40 prevents bacteria from entering the container 12 through the drain openings 20 and the filter sheet 34 prevents bacteria from entering the container 12through the lid 22. Items in the container 12 will remain sterilized until the lid 22 is removed. Both the container 12 and the element 40 are reuseable.

Various features of the invention are set forth in the following claims.

Claims

1. An apparatus for containing items during sterilization and for storing the items after sterilization, said apparatus comprising a container including a bottom wall having therein a drain opening, said bottomwall sloping downwardly toward said drain opening, and porous means located adjacent said drain opening for permitting the drainage of water from said container through said drain opening and for preventing the entry of bacteria into said containerthrough said drain opening in the absence of water drainage.

2. An apparatus as set forth in Claim 1 wherein said porous means includes an element which is water permeable and nonabsorbent and which is substantially impervious to bacteria when dry.

3. An apparatus as setforth in Claim 2 wherein said element is made of permeable ceramic material.

4. An apparatus as setforth in Claim 5wherein said element its further made of ceramic particlessintered together with a glass binder.

5. An apparatus as set forth In Claim 4wherein said element has not more than one micron permeability in air and has a thickness of not less than 3/16 inch whereby said element creates a tortuous path for airborne bacteria.

6. An apparatus as set forth in Claim 2 wherein said element is further made of nonabsorbent particles sinteredtogetherwith a glass binder.

7. An apparatus as set forth in Claim 2 wherein said bottom wall includes a downwardly extending recess having therein a plurality of drain openings, wherein said bottom wall slopes downwardly toward said recess, and wherein said element is located in said recess.

8. An apparatus as set forth in Claim 7 wherein said recess and said element are circular, and wherein said apparatusfurthercomprises an annular gasket located between said element and said bottom wall,and means for securing said element in said recess to trap said gasket between said element and said bottom wall.

9. An apparatus as set forth in Claim 1 wherein said container includes a base having an open upperend and a lower end including said bottom wall, and a lid securable on said open upper end of said base,and wherein said apparatus further comprises a perforated tray removably located in said containerfor support- ing the items to be sterilized and stored.

10. An apparatus as set forth in Claim 1 wherein said container has an interior, and wherein said porous means is located interiorly of said container.

11. An apparatus for containing items during sterilization and for storing the items after sterilization, said apparatus comprising a container including a bottom wall having therein a drain opening, and an element located adjacent said drain opening for permitting the drainage ofwaterfrom said containerthrough said drain opening, said element being water permeable and nonabsorbent and being substantially impervious to bacteria when dry.

12. An apparatus as set forth in Claim 11 wherein said element is made of permeable ceramic material.

13. An apparatus as set forth in Claim 12 wherein said element is further made of ceramic particles sinte- red together with a glass binder.

14. An apparatus as setforth in Claim 13 wherein said element has not more than one micron permeability in air and has a thickness of not less than 3/16 inch whereby said element creates a tortuous path for airborne bacteria.

15. An apparatus as set forth in Claim 11 wherein said element is made of nonabsorbent particles sintered together with a glass binder.

16. An apparatus as set forth in Claim 11 wherein said bottom wall incudes a downwardly extending recess having therein a plurality of drain openings, wherein said bottom wall slopes downwardlytoward said recess, and wherein said element is located in said recess.

17. An apparatus as set forth in Claim 16 wherein said recess and said element are circular, and wherein said apparatusfurthercomprises an annular gasket located between said element and said bottom wall,and meansforsecuring said element in said recess to trap said gasket between said element and said bottom wall.

18. An apparatus as setforth in Claim 11 wherein said container includes a base having an open upper end and a lower end including said bottom wall, and a lid securable on said open upper end of said base, and wherein said apparatus further comprises a perforated tray removably located in said containerforsupport- ing the items to be sterilized and stored.

19. An apparatus as set forth in Claim 11 wherein said container has an interior, and wherein said element is located interiorly of said container.

20. An apparatus for containing items during sterilization and for storing the items after sterilization,said apparatus comprising a container including a base having an upen upper end and a lower end including a bottom wall, said bottom wall including a circular recess having therein a plurality of drain openings, and said bottom wall sloping downwardly toward said recess, a lid securable on said open upper end of said base, and a perforated tray removably located in said container for supporting the items to be sterilized and stored, a circular, water permeable, nonabsorbent element located in said recess adjacent said drain openings, said element being made of ceramic particles sintered together with a glass binder, and said element having not more than one micron permeability in air and having a thickness of not less then 3/16 inch whereby said element creates a tortuous path for airborne bacteria, an annular gasket located between said element and said bottom wall, and means for securing said element in said recess to trap said gasket between said element and said bottom wall, whereby said element permits the drainage ofwaterfrom said container through said drain openings and, when dry, prevents the entry of bacteria into said container through said drain openings.

21. An apparatus for containing items during sterilization and for storing items after sterilizqtion,the apparatus being substantially as hereinbefore described with reference to the accompany drawing.

Amendments to the claims have been filed, and have the following effect: (a) Claims 1,7,11 and 16above have been deleted ortextuallyamended.

(b) Newortextually amended claims have been filed as follows: (c) Claim 21 above has been re-numbered as 24.

1. An apparatus for containing items during sterilization, and for storing the items after sterilization, said apparatus comprising a container including a bottom wall having therein a drain opening, said bottom wall sloping downwardly toward said drain opening, and porous means located in covering relation to said drain opening for permitting the drainage ofwaterfrom said containerthrough said drain opening and forpreventing the entry of bacteria into said containerthrough said drain opening in the absence of water drainage.

7. An apparatus as set forth in claim 2 wherein said bottom wall includes a downwardly extending recess having therein a purality of said drain openings, wherein said bottom wall slopes downwardly toward said recess, and wherein said element is located in said recess in covering relation to said drain openings.

11. An apparatus for containing items during sterilization, and for storing the items after sterilization, said apparatus comprising a container including a bottom wall having therein a drain opening, and an element located in covering relation to said drain opening for permitting the drainage ofwaterfrom said container through said drain opening, said element being water permeable and nonabsorbent and being substantially impervious to bacteria when dry.

16. An apparatus as set forth in claim 11 wherein said bottom wall includes a downwardly extending recess having therein a plurality of said drain openings, wherein said bottom wall slopes downwardlytoward said recess, and wherein said element is located in said recess in covering relation to said drain openings.

21. An apparatus as set forth in claim 1 wherein said bottom wall includes a downwardly extending recess having therein a plurality of said drain openings, wherein said bottom wall slopes downwardlytoward said recess, and wherein said porous means is located in said recess in covering relation to said drain openings.

22. An apparatus for containing items during sterilization and for storing the items after sterilization, said apparatus comprising a container including a bottom wall having therein a depending drains recess and wall portions sloping downwardlytoward said recess, a drain opening in said recess, and porous means located in said drains recess in covering relation to said drain opening for permitting the drainage of water from said container through said drain opening and for preventing the entry of bacteria into said containerthrough said drain opening in the absence of waterdrainage.

23. Apparatus in accordance with claim 22 wherein said containerfurther includes a plurality of legs which have respective ends terminating in a common plane and which extend downwardly from said bottom wall to below said recess so asto locate said recess above the common plane to facilitate drainage ofwater from said recess.