WO1993015969A1

WO1993015969A1 - Reusable, resealable sterilization bag

Info

Publication number: WO1993015969A1
Application number: PCT/US1993/001476
Authority: WO
Inventors: Thomas H. Thompson, Jr.
Original assignee: Thompson Dental Manufacturing Co.
Priority date: 1992-02-18
Filing date: 1993-02-18
Publication date: 1993-08-19

Abstract

A reusable, resealable sterilization bag including a pouch (100) having an opening (110), and a resealable closure (116) for the pouch's opening. The pouch (100) is sized to accept the instrument cassette, instrument or object with which it is to be used. The resealable closure may include a pair of velcro strips (241 and 126) and first, second and third folds in the pouch near its opening (110). The pouch is made from a material which is permeable to the sterilant with which it is to be used; which is at least substantially impermeable to dust and water particles which might carry infectious microorganisms; and which can withstand repeated, successive sterilization cycles.

Description

REUSABLE, RESEALABLE STERILIZATION BAG

Field of the Invention

The present invention relates to a sterilization bag for holding an instrument cassette while the cassette and its contents are being sterilized, and for helping to prevent post-sterilization contamination of the instrument cassette and its contents.

More particularly, the present invention relates to such a sterilization bag which is reusable and resealable.

Summary of the Invention

After medical or dental instruments are used, they must be sterilized to prevent cross-infection between successive users of the instruments. Then, after sterilization, the instruments must be protected from contamination by contact with objects or people, and they must be protected from contamination by dust and water particles which might carry infectious microorganisms.

Conventionally, there are two main ways of protecting instruments or objects after the sterilization process. The first way is to use a disposable, sealable pouch, envelope or bag into which the instruments or objects are placed prior to being sterilized. The pouch, envelope or bag may be made from impermeable material, such as plastic, or it may be made from a material which is permeable to the sterilant, but which is at least substantially impermeable to dust or water particles which may carry infectious microorganisms. Since such pouches, envelopes or bags an: discarded after only one use, their use is wasteful and environmentally unsound, since they undesirably increase the waste stream which must then be disposed of

The second main way of protecting instruments or objects after the sterilization process is to place the instruments or objects to be sterilized in an instrument cassette prior to being sterilized. This makes the sterilization of several objects or instruments at the same time more convenient. The instrument cassette is perforated in order to permit the sterilant, such as gas or steam, to come into contact with the instruments or objects within the instrument cassette during the sterilization process.

Conventionally, the instrument cassette is wrapped by hand in a sheet of material prior to sterilization. The sheet material is held in place around the instrument cassette with tape or any other suitable conventional fastener. The sheet material is permeable to the sterilant, such as gas or steam, and permits it to come into contact with the instrument cassette and its contents during the sterilization process. The sheet material protects the instrument cassette and its contents from post- sterilization contamination by contact with objects or people; while the instrument cassette helps keep the instruments or objects within it from puncturing or ripping the sheet material. In addition, since the sheet material is at least substantially impermeable to dust and water particles, which might carry infectious microorganisms, it helps to protect the instrument cassette and its contents from post- sterilization contamination. When the contents of the instrument cassette are needed, the sheet material is removed from the instrument cassette.

Such conventional use of sheet material to wrap the instrument cassettes has at least two drawbacks. First, the sheet material is relatively expensive to use because it is time consuming to individually hand wrap the instrument cassettes with the sheet material and to tape it in place prior to sterilization. The sheet material is also relatively expensive to use because it is normally thrown away after only one use, thereby requiring new sheet material to be purchased each time an instrument cassette is to be sterilized.

Second, since the sheet material is normally thrown away afbr only one use, the use of such sheet material is wasteful and environmentally unsound, since the discarded sheet material undesirably increases the waste stream which must then be disposed of. In basic form, the sterilization bag of the present invention comprises a pouch which is sized to accept the particular instrument cassette, instrument or object which needs to be sterilized. The pouch is made from a material which is selected to be permeable to the sterilant, such as gas or steam; and to be at least substantially impermeable to particles of dust and water which might ';arry infectious microorganisms. The material from which the pouch is made is also selected to be durable, so that it can withstand many sterilization cycles without losing its ability to perform its functions of protecting the instruments from post-sterilization contamination by contact with objects or people, and of helping to protect the instruments from post-sterilization contamination by dust and water particles which might carry infectious microorganisms. This permits the sterilization bag to be reused many times.

The sterilization bag may be provided with resealable closure means to permit the pouch to be closed after the instrument cassette or instruments are placed within it; and to permit the pouch to be opened when its contents are needed. This also permits the sterilization bag to be reused many times. The closure means may comprise at least double or triple folds of the top portion of the pouch, which are then held in place by closure means such as conventional hook and loop velcro type material. Alternatively, the closure, means may comprise any suitable conventional resealable fastening means, such as a zipper, a zip-lock type of fastening device, or a deformable bar, for example. The present invention provides an economical, reusable, resealable sterilization bag which is quick and easy to use.

It should be understood that the foregoing summary of the present invention does not set forth all of its features, advantages, characteristics, structures, methods and/or processes; since these and further features, advantages, characteristics, structures, methods and/or processes of the present invention will be directly or inherently disclosed to those skilled in the art to which it pertains by the following, more detailed description of the present invention.

Brief Description of the Drawings The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is an elevational view of the front of one embodiment of the sterilization bag of the present invention; FIGURE 2 is a view like that of FIGURE 1, but with the top portion of the sterilization bag shown folded over once;

FIGURE 3 is an elevational view of the FIGURE 1 sterilization bag turned inside out, to permit its stitching to be seen;

FIGURE 4 is a longitudinal cross-sectional view of the FIGURE 1 sterilization bag, showing it holding an instrument cassette, and showing its triple fold closure means secured in its sealed configuration; FIGURE 5 is a perspective view of a second embodiment of the sterilization bag of the present invention;

FIGURE 6 is a perspective view of the embodiment of FIGURE 1 showing the end top end of sterilization bag folded over once; and FIGURE 7 is a perspective view of the embodiment of FIGURE 5 showing the top end of the sterilization bag folded over twice and the closure bar deformed to its closed and sealed configuration.

Detailed Description of the Preferred Embodiment Turning now to the Figures, one embodiment of the sterilization bag 10 of the present invention comprises a pouch 11 having a top end 12, a bottom 14, and two sides 16, 18. Its top end 12 defines an opening 20 through which the objects to be sterilized can be inserted into and taken out of the pouch 11.

The pouch 1 1, is formed from a rectangular sheet of material whose two sides 16, 18 are sewn together by conventional stitching 22, as best seen in FIGURE 3. The finished pouch 11 is then turned inside out, as seen in FIGURES 1 and 2, so that its sides 16, 18 are held together by conventional blind seams formed by stitching 22. Alternatively, the pouch's sides 16, 18 could be held or sealed together by any other conventional means, such as by gluing, melting, heat welding or sonic welding, for example. The pouch 11 is provided with complimentary front and back strips 24, 26 of conventional velcro type hook and loop fastening material, which ate secured to the front and the back of pouch 11 , respectively, by any conventional means, such as by sewing, gluing, melting, heat welding or sonic welding, for example The strips 24, 26 are used to releasably seal the pouch's top opening 20 in a manner which will be described below. Pouch 11 preferably has a free end portion 27 which is located between the upper edge of velcro strip 26 and the pouch's top end 12, as best seen in FIGURES 1-3.

During use, the instruments or objects to be sterilized are normally placed in an instrument cassette 28, which is then inserted into pouch 1 1 through its top opening 20. Alternatively, the instruments or objects to be sterilized may be placed directly into the pouch 11, although this is not preferred since they might puncture or tear the pouch 11. The instrument cassette 28 is of conventional construction, and comprises a top 30 and a bottom 32 held together by a piano hinge 34. The instrument cassette 28 is not a part of the present invention. For clarity, no instruments are shown inside of instrument cassette 28. The pouch 11 may be made in any size and shape which may be needed in order for it to accommodate the particular instrument cassette 28, instruments, or objects with which it is intended to be used.

The pouch 11 may be made from any material which is permeable to the sterilant intended to be used, which is at least substantially impermeable to dust and water particles which might carry infectious microorganisms, and which is compatible with the contemplated sterilization process.

By way of non-limiting example, the pouch 11 may be made from a conventional material which is a triple layer, non-woven, cross-laminated fabric. Each layer of the fabric may be made from conventional 3-ounce Nylon 6,6, or polypropylene having an average pore size of from 5 to 7 microns, an average thickness of 18 mils, a 122 pounds machine direction grab strength, a 92 pounds transverse direction grab strength, a 34 pound machine direction tear strength, a 24 pound transverse direction tear strength, a 96 pounds per square inch Muilen Burst strength, an air permeability of 180 cubic feet per minute per square foot, a melting point of approximately 500°F, an excellent dimensional stability up to 400°F, an ability to be processed at temperatures as high as 425°F for limited periods of time, a Class 2 flammability rating under the Department of Commerce Flammable Fabrics Act, a resistance to attack by many solvents, alkali and dilute acids found in manufacturing and sterilization processes, and a resistance to insect, mildew and bacteria. Naturally, any one or more of the foregoing characteristics could be varied according to the needs or desires of the particular user, fewer or more layers of the fabric may be used, and woven fabric might be used.

Alternatively, the pouch 11 may be made from any material which is impermeable to dust and water particles, and which is compatible with the contemplated sterilization procedure, such as a plastic film made from nylon, polypropylene or any other suitable conventional plastic material.

After the instrument cassette 28, instruments or objects to be sterilized are placed inside of pouch 11, it's top opening 20 is then releasably sealed in the following manner. First, its top portion is folded over once, to form a first fold 36 from the sealing portion 42 of pouch 11 which lies between velcro strips 24, 26. After the first fold 36 is made, the pouch's free end portion 27 is located at least substantially between velcro strips 24, 26, as best seen in FIGURE 2. It is important that the pouch's free end portion 27 does not completely cover velcro strip 26, since that would make it impossible for the velcro strips 24, 26 to be secured to each other after the next fold, which is described below, is made. Lastly, the top portion of pouch 1 1 is folded again to secure velcro strip 26 to velcro strip 24, thereby simultaneously forming second and third folds 38, 40, respectively, as best seen in FIGURE 4. As seen, the second fold 38 is formed from the sealing portion 42 of the pouch 1 1 which lies between velcro strips 24, 26; while the third fold 40 is formed from the pouch's free end portion 27.

The combination of the velcro strips 24, 26 with the first, second and third folds 36, 38 and 40 form an effective releasable seal for the pouch's opening 20, in order to help prevent post-sterilization contamination of the instrument cassette 28, instruments or objects within the pouch 11 by dust and water particles which might carry infectious microorganisms. To remove the instrument cassette 28, instruments or objects from the pouch 1 1, the velcro strips 24, 26 are simply detached from each other, and then the first, second and third folds 36, 38, 40 are unfolded.

Alternatively, the pouch's free end portion 27 could be eliminated, resulting in the formation of only the first and third folds 36, 40 when the pouch 1 l's top portion is folded over twice and secured with the velcro strips 24, 26 in the manner described above.

Alternatively, the velcro strips 24, 26 could be replaced with any other suitable, conventional fastening means such as snaps or ties, for example.

Alternatively, any suitable, conventional form of closure means could be used to releasably close the pouch's opening 20 instead of the folds 36, 38, 40 and velcro strips 24, 26 described above, such as zippers, zip-lock type of fasteners or closure bars, for example.

Between uses, the pouch 11 can be washed with soap and water, if desired. From the foregoing, it is seen that the present invention provides an economical, reusable, resealable sterilization bag which is quick and easy to use.

FIGURES 5-7 illustrate a second embodiment of the present invention. Features of the second embodiment not described herein are the same as the first embodiment and may be understood by reference to the disclosure for the first embodiment. The second embodiment is a sterilization bag includ'ng a pouch 100 having a top end 102, a bottom end 104, and opposing sides 106 and 108. An opening 110 through which objects to be sterilized can be inserted into and taken out of the pouch is located adjacent the top end.

The pouch 100 can be formed of any shape and size, the second embodiment is formed from top and rectangular sheets of material 112 and 1 that are held together along the sides 106, 108 and bottom end 104. Top and bottom sheets 1 12 and 1 14 may be held together by any conventional means such as stitching, heat sealing, adhesive bonding, or other means well known in the art. In the second embodiment, the top and bottom sheets 172 and 114 are formed of a polypropylene woven material held together by heat sealing the sides and bottom end of the pouch. The top sheet 112 of the pouch is sized so that its top end 115 does not extend all the way to the top end 102 of the pouch. The top end 115 of the top sheet 112 is not attached to the bottom sheet 114 in order to form opening 110 into which objects to be sterilized can be inserted into or taken out of the pouch.

A closure bar 116 is attached to the bottom sheet 1 14 adjacent the top edge 102 of the pouch. The closure bar 116 is sized sufficiently long so that the opposing ends or tabs 120 and 122 extend past the sides 106 and 108, respectively. This configuration allows the tabs 120 and 122 to be deformed so as to secure the pouch 100 in a closed and sealed position as described in more detail below. Closure bar 116 may be attached to bottom sheet 114 by any appropriate attachment means, for example, rivets 124 as shown in the second embodiment, or alternatively by adhesive bonding, stitching, or other fastening means. Closure bar 116 may be formed of any material capable of being deformed, of maintaining a deformed configuration and of withstanding multiple deformations prior to failure. In the preferred embodiment, the closure bar 116 is formed of stainless steel

During use, instruments or objects to be sterilized are placed within pouch 100 or within an instrument cassette and subsequently within the pouch prior to sealing. The pouch 100 is then closed and sealed by folding top end 102 of the pouch, including the closure bar 116, downwardly as illustrated in FIGURE 6 forming a first fold 126. For clarification, the pouch 100 is shown in phantom in its unfolded configuration and in solid line in its folded configuration. The top end of the pouch 102 is then folded downwardly as shown in FIGURE 7 to form a second fold 128. The folding process may be repeated as desired in order to ensure a proper sealing of the opening 110. In the second embodiment, it was found ihat an optimum seal is achieved with at least three folds, but in most applications two folds will provide a sufficient seal a second time. After folding, the tabs 120 and 122 of the closure bar 116 are deformed rearwardly around the first, second and any subsequent fold so as to lie adjacent to the backside of the bottom sheet 114 as shown in phantom in FIGURE 7 and labeled as 131 and 132 respectively. Deforming the tabs 120 and 122 of the closure bar as described ensures that the top portion of the pouch including the first and second folds 126 and 128 will maintain folded. The combination of the first, second and any subsequent folds and the closure bar 116 forms an effective resealable seal for the pouch's opening 1 10 that prevents contamination of the interior of the sterilization bag and any objects contained therein by dust or water particles which might carry infectious microorganisms.

After sealing, the pouch is sterilized. The sterilized instruments may then be maintained sterile within the pouch until needed. To remove objects contained within the sterilization bag, the tabs 120 and 122 of the closure means 116 are deformed back to their original position, the top end of the pouch is unfolded and the objects are removed. As discussed above, as an alternative to the closure bar 116, other closure means such as hook and latch fasteners, snaps, buttons, zip lock fasteners, or other fastening methods could be used.

As illustrated in FIGURE 1, the second embodiment also includes a window 130 in the top sheet 112. The window 130 allows the user to view the contents of the sterilization bag. The window 113 can be any suitable size and shape and can be contained within a section of the top sheet 1 12 or could encompass the entire dimension of the top sheet. Window 130 is attached to top sheet 112 in such a way as to form a seal around the periphery of the window to prevent dust and water particles from entering through the interface between the window and the top sheet 112. Any suitable fastening means such as adhesive bonding, heat sealing, stitching or other fastening and sealing means can be used to attach the window 130 to the top sheet 112. In the second embodiment, the window is formed from clear polypropylene, however, other materials capable of withstanding sterilization procedures could also be used.

The second embodiment also includes a calendar 132 that allows the user to track the sterilization bag's use. In the second embodiment, the calendar is located on the top sheet 112 above the window, however, it could be placed in other locations. The calendar can be attached to the top sheet 112 using any attachment means, such as stitching, adhesive bonding, heat sealing, or other fastening means. The calendar is divided into a series of portions 134 that provide the user space ir. which to mark when the sterilization bag was last used, how many times it has been used, or with other information relevant to its use. Thus, calendar 132 allows the user to accurately track the bag's use in order to prevent accidental contamination of the bag or the articles contained therein.

In the second embodiment, the calendar includes thirty portions 134, thus allowing the user to track thirty uses of the sterilization bag. Experimental tests have shown that over time, woven polypropylene becomes more porous. Thus, after a certain number of uses, its possible contaminants could pass though the polypropylene material contaminating the contents of the sterilization bag. Tests have shown that thirty uses ensures a safe pouch life for the materials used in the second embodiment. However, each material should be tested to determine what a safe lifetime is prior to use.

While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

Claims

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

1. A reusable sterilization bag for holding articles to be sterilized, the sterilization bag comprising: a pouch including a top sheet, a bottom sheet and an opening into the pouch; and closure means located adjacent the opening for releasably closing the sterilization bag so as to prevent dust and infectious microorganisms from entering the sterilization bag, said closure means comprising a first fold formed in the top and bottom sheets near the opening so as to close the sterilization bag, a second fold formed in the top and bottom sheets near the opening, a portion of the top and bottom sheets forming the second fold being located adjacent a portion of the top and bottom sheets forming the first fold and releasable securing means for securing the first and second folds so as to maintain the sterilization bag closed.

2. The sterilization bag of Claim 1, wherein the securing means comprises a hook and loop fastener located near the opening so as to secure the first and second folds thereby maintaining the sterilization bag closed.

3. The sterilization bag of Claim 2, wherein the hook and loop fastener comprises a first strip located on the exterior surface of the top sheet and a second strip located on the exterior surface of the bottom sheet nearer to the opening than the first strip.

4. The sterilization bag of Claim 1, wherein the securing means comprises a deformable closure bar located adjacent the opening.

5. The sterilization bag of Claim 1, further comprising a calendar for tracking the sterilization bag's use and a window for viewing the sterilization bag's contents.

6. The sterilization bag of Claim 1, wherein the securing means comprises a zip-lock type fastener.

7. A reusable sterilization bag for holding articles to be sterilized, the sterilization bag comprising: a pouch including a top sheet, a bottom sheet and an opening into the pouch; and closure means located in the opening for releasably closing the sterilization bag so as to prevent dust and infectious microorganisms from entering the sterilization bag, said closure means comprising a hook and loop fastener located near the opening so as to releasably close the sterilization bag, the hook and loop fastener including a first strip located on the exterior surface of the top sheet and a second strip located on the exterior surface of the bottom sheet nearer to the opening than the first strip.

8. The sterilization bag of Claim 1, further comprising a calendar for tracking the sterilization bag's use and a window for viewing the sterilization bag's contents.

9. A method for releasably closing a reusable sterilization bag, the method comprising the steps of

(a) providing a sterilization bag including top and bottom sheets joined to form a pouch and an opening into the pouch;

(b) folding a first portion of the top and bottom sheets near the opening so as to close the sterilization bag;

(c) folding a second portion of the top and bottom sheets near the open so that the second portion of the sheets overlies the first portion so as to releasably close the sterilization bag to prevent dust and infectious microorganisms from entering the sterilization bag; and

(d) securing the sterilization bag in the closed and folded position.

10. The method of Claim 9, wherein step (d) further comprises securing the sterilization bag in the closed position with a hook and loop fastener.

11. The method of Claim 9, wherein step (d) further comprises securing the sterilization bag in the closed position with a zipper.

12. The method of Claim 9, wherein step (d) further comprises securing the sterilization bag in the closed position with a zip-lock type fastener.

13. The method of Claim 9, wherein step (d) further comprises securing the sterilization bag in the closed position with a deformable closure bar.