AU597943B2

AU597943B2 - Instrument sterilization container

Info

Publication number: AU597943B2
Application number: AU69730/87A
Authority: AU
Inventors: Kenneth V. Pepper
Original assignee: Bemis Manufacturing Co
Current assignee: Individual
Priority date: 1986-04-07
Filing date: 1987-03-05
Publication date: 1990-06-14
Anticipated expiration: 2007-03-05
Also published as: DK168424B1; SE8701102L; BE1001375A3; DE3711621A1; ES2005128A6; NO871389L; NL8700768A; JPH0822309B2; SE8701102D0; FR2596652B1; SE501170C2; NL193209C; NO871389D0; NO169697C; JPS62266061A; GB2188549A; DE3711621C2; GB8705250D0; CA1271017A; FR2596652A1

Description

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AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION S7 Form Form

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: 6q73O/S 7 Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: 4I Q

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'rIl '(i TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Actual Inventor: BEMIS MANUFACTURING COMPANY 300 MILL STREET SHEBOYGAN FALLS WISCONSIN 53085

U.S.A.

CLEMENT HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3004, Australia.

.'Address for Service: t i t t -t Complete Specification for the invention entitled: INSTRUMENT STERILIZATION CONTAINER ."The following statement is a full description of this invention including the best method of performing it known to me:- 1A INSTRUMENT STERILIZATION CONTAINER BACKGROUND OF THE INVENTION The invention relates to apparatus for containing items such as hospital instruments during sterilization and for storing the items after sterilization.

It is known to sterilize hospital instruments in an autoclave by subjecting the instruments to one or more vacuum/steam cycles.

After the desired number of vacuum/steam cycles, a Svacuum is drawn to expedite evaporation of moisture I or condensation remaining on the instruments.

It is also known to place the i instruments in a container during this sterilization j 15 process. Typically these containers are made of 1 metal and include openings permitting vacuums to be i drawn in the containers and steam to enter the containers. The openings are covered with filters A 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.

i- 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 permit water to pass through, they generally absorb any water that reaches them. Some metal containers have in their bottom walls temperature-sensitive valves which permit water drainage until the O o temperature of the container drops below a certain 0000 0 point. These valves are subject to failure, they 00 0 °O have complicated constructions, and one cannot see o whether they have closed without opening the o 0 0 o 0 15 container and exposing the contents.

Recently, plastic containers have ooo become popular because they can be made transparent, 0 so their contents are visible, because they are not o a 0as hard as metal containers, so they do not damage 0 0 sharp instruments, and because they conduct heat o 0 slowly, so they are easier to 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 the adjacent plastic.

-3- 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 together with a glass binder, for filtering liquids or for 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 44 SUMMARY OF THE INVENTION The invention provides an apparatus for containing items during sterilization and for storing the items after sterilization, said apparatus comprising a container including an open top, a bottom wall having therein a drain opening, said bottom wall slopping downwardly toward said drain opening, and porous means located adjacent said drain opening and operable, during a period of repeated usage, to permit the drainage of water from said container through said drain opening and to prevent the entry of bacteria into said container through said drain opening in the absence of water drainage, and a removable lid affording closure of o, said open top and access to said container when said lid is removed.

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

Preferably, the element has not more than one micron of permeability in air, and it has a thickness of not less Al A> than 3/16 inch. As a result, the element creates a tortuous path for airborne bacturia and substantially prevents bacteria from passing through it. In the preferred embodiment, the element is made of nonabsorbent particles sintered together with 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 Swall slopes downwardly toward the recess, and the element is located in the recess. More particularly, j both the recess and the element are circular, and the Sapparatus further comprises an annular gasket located i between the element and the bottom wall, and means i i i for securing the element in the recess to trap the gasket between the element and the bottom wall. This 9i 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.

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-6- Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.

DESCRIPTION OF THE DRAWINGS Fig. 1 is a vertical cross-sectional view of an apparatus which embodies various of the features of the invention and which includes a container having a lid and containing an instrument tray.

Fig. 2 is a top view of the container with the lid and instrument tray removed.

Before one embodiment of the invention rs~ i irar r 1 t is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of U tl 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 should not be regarded as limiting.

-7- 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 best shown in Fig. 1, the apparatus comprises 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 ib extending recess 18 having therein a plurality of drain openings 20, and the bottom wall 16 slopes i downwardly toward the recess 18. In the preferred embodiment, the bottom wall 16 slopes downwardly at i an angle of not less than 4.5 degrees. In the t illustrated construction, the recess 18 is generally circular, and the base 14 also includes a plurality of inwardly extending ribs 21, the reason for which is explained hereinafter.

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

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4 The container 12 also includes a lid 22 securable on the open upper end of the base 14. The lid 22 can be secured to the base 14 by any suitable means (not shown). In the illustrated construction, the lid 22 includes, around its periphery, a downwaruly 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 14 for sealing the lid 22 to the base 14. The lid 22 also includes a plurality of openings 28 for 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 22 further includes an annular, downwardly extending boss surrounding the openings 28, and a perforated, circular supporting frame 32 mounted on the boss The supporting frame 32 supports, on its upper surface, a sheet 34 of filter material for permitting steam to enter the 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.

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L_;I~1* -9- 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 inside the 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 o °porous means located adjacent the drain openings for permitting the drainage of water from the o container 12 through the drain openings 20 and for o 0 0 POpreventing the entry of bacteria into the container o 0l' 12 through the drain openings 20 in the absence of 15 water drainage. While various suitable porous means 00 can be employed, in the preferred embodiment, this means includes an element 40 which is water permeable 00 00 S° and nonabsorbent and which is substantially impervious to bacteria when dry. Preferably, the 0 0 20 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 embodiment, the controlled size particles are particles of silicon carbide.

Furthermore, in the preferred embodiment, the element has not more than 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 resistance that parallels that of glass, so that it is resistant to corrosion, oxidation, and other conditions of steam sterilization.

In alternative embodiments, the element 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 particles 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 is located in the recess 18 and thus interiorly of the 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 16 with the element 40 located on the bottom wall 16 adjacent the 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 side wall 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 a 2 the bottom wall 16 and the element 40. This device is preferably made of stainless steel. In the illustrated construction, an 0-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 -12- 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 enter the container 12. Items to be sterilized are supported on the tray 36, and condensation from the items passes through the openings 38 in the lower wall of the tray 36 onto the bottom wall 16 of 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 passes 0 through the element 40 and out the drain openings 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 12 through 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

2. An apparatus as set forth in Claim 1 wherein said porous means includes an element which is water permeable and non absorbent and which is substantially impervious to bacteria when dry.
3. An apparatus as set forth in Claim 2 wherein said element is made of permeable ceramic material.
4. An apparatus as set forth in Claim 2 wherein said element is further made of ceramic particles sintered together with a glass binder. -14- An apparatus as set forth in Claim 4 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.
6. An apparatus as set forth in Claim 2 wherein said element is further made of nonabsorbent particles sintered together with a glass binder. 0* o
7. An apparatus as set forth in Claim 0 2 wherein said bottom wall includes a downwardly extending recess having therein a plurality of drain o 4 openings, wherein said bottom wall slopes downwardly 5 toward said recess, and wherein said element is 00 o on. oo located in said recess. 0 00 04 00 a a 0 0
8. An apparatus as set forth in Claim 7 wherein said recess and said element are circular, o 09 00o and wherein said apparatus further comprises 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. .K 15
9. An apparatus as set forth in Claim 1 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 container for supporting the items to be sterilized and stored. 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 an open top, a bottom wall having therein a drain opening, and an element located adjacent said drain opening an operable to permit the drainage of water from said container through said drain opening during a period of repeated usage, said element being water permeable and non-absorbent during the period of repeated usage and being substantially impervious to bacteria when dry during the period of repeated usage, and a removable lid affording closure of said open top and access Sto said container when said lid is removed. a 4z
12. An apparatus as set forth in Claim 11 wherein S said element is made of permeable ceramic material. -16- i I I
13. An apparatus as set forth in Claim 12 wherein said element is further made of ceramic particles sintered together with a glass binder.
14. An apparatus as set forth 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. An apparatus as set forth in Claim 4, 11 wherein said element is made of nonabsorbent 44 particles sintered together with a glass binder. S
16. An apparatus as set forth in Claim 11 wherein said bottom wall includes a downwardly B 4 extending recess having therein a plurality of drain openings, wherein said bottom wall slopes downwardly 00 04, toward said recess, and wherein said element is located in said recess. .A o 0
17. An apparatus as set forth in Claim 16 wherein said recess and said element are circular, and wherein said apparatus further comprises 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. I -17-
18. An apparatus as set forth 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 container for supporting the items to be sterilized and stored.
19. An apparatus as set forth in Claim 11 wherein said container has an interior, and Swherein said element is located interiorly of said 0c i S*container. *a o -18- An apparatus for containing items during sterilization and for storing the items after sterilization, said apparatus comprising a container including a base having an open 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, o a circular, water permeable, nonabsorbent element oa located in said recess adjacent said drain openings, 15 together with a glass binder, and said element having not more than one micron permeability in air and 0 9. having a thickness of not less than 3/16 inch whereby oo 0 said element creates a tortuous path for airborne bacteria, an annular gasket located between said element and said bottom wall, and means for securing 3, o said element in said recess to trap said gasket between said element and said bottom wall, whereby said element permits the drainage of water from said container through said drain openings and, when dry, prevents the entry of bacteria into said container through said drain openings. DATED THIS 5TH DAY OF MARCH 1987 BEMIS MANUFACTURING COMPANY By its Patent Attorneys: CLEMENT HACK CO. Fellows Institute of Patent Attorneys of Australia.