U.S. patent application number 14/706904 was filed with the patent office on 2015-11-05 for sterilisation services apparatus and method of sterilisation.
The applicant listed for this patent is Mercer Technologies Limited. Invention is credited to Christo Andre De Klerk, Terry Dean Kemp.
Application Number | 20150314899 14/706904 |
Document ID | / |
Family ID | 42561950 |
Filed Date | 2015-11-05 |
United States Patent
Application |
20150314899 |
Kind Code |
A1 |
Kemp; Terry Dean ; et
al. |
November 5, 2015 |
STERILISATION SERVICES APPARATUS AND METHOD OF STERILISATION
Abstract
A method of sterilising items by placing items to be sterilised
into a puncture resistant sealable vapour barrier sterilisation
bag, performing steam sterilisation under pressure via a conduit
coupled to the bag whilst maintaining a heated compensating
pressure environment around the exterior of the bag during steam
sterilisation so as to reduce mechanical stress on the hag and
sealing the bag at the completion of sterilisation. There is also
provided a sterilisation services apparatus for sterilising the
contents of a sterilisation bag including a pressure compensating
compartment having a sealable door that maintains a heated
compensating pressure environment around the exterior of a
sterilisation bag during steam sterilisation so as to reduce
mechanical stress on the bag.
Inventors: |
Kemp; Terry Dean; (Auckland,
NZ) ; De Klerk; Christo Andre; (Queensland,
AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mercer Technologies Limited |
Auckland |
|
NZ |
|
|
Family ID: |
42561950 |
Appl. No.: |
14/706904 |
Filed: |
May 7, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13201169 |
Nov 15, 2011 |
9027311 |
|
|
PCT/NZ2010/000022 |
Feb 12, 2010 |
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14706904 |
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Current U.S.
Class: |
53/425 ;
53/127 |
Current CPC
Class: |
A61L 2/07 20130101; B65B
55/18 20130101; B65B 31/024 20130101; B65B 7/02 20130101; A61L
2202/14 20130101; A61L 2202/23 20130101; B65B 5/045 20130101; B65B
55/10 20130101 |
International
Class: |
B65B 55/18 20060101
B65B055/18; A61L 2/07 20060101 A61L002/07; B65B 55/10 20060101
B65B055/10; B65B 5/04 20060101 B65B005/04; B65B 7/02 20060101
B65B007/02 |
Claims
1-16. (canceled)
17. A method of sterilising items including the steps of: I.
placing items to be sterilised into a puncture resistant sealable
vapour barrier sterilisation bag; II. performing steam
sterilisation under pressure via a conduit coupled to the bag
whilst maintaining a compensating pressure environment around the
exterior of the bag during steam sterilisation so as to reduce
mechanical stress on the bag; and III. sealing the bag at the
completion of sterilisation.
18. A method as claimed in claim 17 wherein after placing the items
into the bag, the bag is sealed so as to leave only an opening
suitable for sealingly coupling with the conduit.
19. A method as claimed in claim 17 wherein the bag is evacuated
prior to steam sterilisation and the pressure around the bag is
reduced below atmospheric pressure during evacuation so as to
facilitate effective evacuation of the bag.
20. A method as claimed in claim 17 wherein steam sterilisation is
performed within the bag at above atmospheric pressure and the
pressure around the bag is maintained above atmospheric pressure
during steam sterilisation so as to reduce mechanical stress on the
bag.
21. A method as claimed in claim 17 wherein the bag is maintained
in a pressure compensating compartment during sterilisation.
22. A method as claimed in claim 17 wherein the interior of the bag
and items within the bag are dried during the evacuation of the
sterilant from within the bag after the sterilization cycle.
23. A method as claimed in claim 22 wherein the exterior of the
inflated bag is maintained in contact with heated surfaces during
the sterilisation and drying cycle to facilitate drying of the
interior of the bag and items to be sterilised.
24. A method as claimed in claim 17 wherein a drying fluid is
introduced via an opening in the bag, circulated within the bag and
removed from the bag to facilitate drying of items in the bag.
25. A method as claimed in claim 23 wherein the bag is sealed after
sterilisation and drying within the pressure compensating
compartment before the pressure compensating compartment is
opened.
26. A method as claimed in claim 25 wherein the bag is heat
sealed.
27. A sterilisation services apparatus for sterilising the contents
of a sterilisation bag including: I. a pressure compensating
compartment having a sealable door that maintains a compensating
pressure environment around the exterior of a sterilisation bag
during steam sterilisation and drying so as to reduce mechanical
stress on the bag; II. a fluid conduit adapted to couple to an
opening of a sterilisation bag during sterilisation within the
pressure compensating compartment; III. a steam generator to supply
steam to the bag via the conduit; IV. a bag sealing unit to seal
the opening of the sterilisation bag, and V. a vacuum pump for
evacuating a sterilisation bag via the conduit prior to steam
sterilisation.
28. A sterilisation services apparatus as claimed in claim 27
including a pair of fluid conduits adapted to couple with one or
more openings of the sterilisation bag to facilitate the
circulation of fluid in via one conduit and out via another.
29. A sterilisation services apparatus as claimed in claim 28
wherein heated air is supplied to facilitate drying of the load
within the sterilisation bag.
30. A sterilisation services apparatus as claimed in claim 27
including a clamp to form a sealed connection between the conduit
and an opening of a sterilisation bag by applying a clamping
pressure thereto.
31. A sterilisation services apparatus as claimed in claim 27
including a heat sealing bar and anvil to heat seal the bag in
front of the conduit coupling.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a method of sterilisation and a
sterilisation services apparatus. More particularly, although not
exclusively, the invention relates to a controlled method and
apparatus to facilitate sterilisation and vacuum packing of a
sterile load within a package without utilising a conventional
steriliser or autoclave.
BACKGROUND TO THE INVENTION
[0002] Sterilisation is required for various industries typically
health care, laboratory, pharmaceutical and food processing
industries. The most common and proven method used for
sterilisation is sterilisation by pressurised high temperature
steam in a pressure chamber or vessel for a prescribed period of
time. Pressurised high temperature steam within a stainless steel
pressure chamber is the preferred method for sterilisation of
laboratory equipment and in the industrial manufacturing and
healthcare sectors.
[0003] Various types of sterilisation pressure vessels and
autoclave chambers are historically utilised to sterilise such
objects, items or products (hereinafter "items"). In all instances
the sterilant must make contact with the surface of the items for
each item to be sterilised in order to enable sterilisation to
occur.
[0004] For moist heat sterilisation using steam as the sterilant,
it is essential that all surfaces of the items requiring
sterilisation are subjected to saturated steam at a predetermined
temperature and pressure for a predetermined period of time. Proper
steam penetration requires adequate air removal.
[0005] Steam is the most widely used agent for sterilisation. In
steam sterilisation, the combination of heat and moisture,
maintained at a pre-set temperature-pressure-time relationship,
coagulates cell protein, efficiently killing the microorganisms.
Its economy and lack of toxicity gives steam an advantage over
other sterilisation methods. The latent heat available is
responsible for the fast destructive power that
steam-under-pressure offers. There can be significant variation in
steam quality and in order for steam to be effective it should have
a dryness fraction of 97% and above.
[0006] Each of the multiple or variable types of steam sterilisers
are designed to achieve specific sterilisation parameters and all
cycles must be validated so that the cycle time and temperature
shall reflect the load and packaging material being processed.
[0007] At the end of a correct sterilisation process, it is
extrapolated that items inside the sterilisation chamber have
reached an acceptable probability of sterility. The challenge to
end users and steriliser manufacturers has been the variety of
loads and varied manner of loading both in respect of how and what
items are loaded and positioned in the chamber and how the load may
be packaged. The load therefore has a direct impact on the relative
efficacy of air removal from the chamber and the efficacy of the
steam on the load and addressing and resolving all these variables
is still a matter under debate.
[0008] In the medical environment, it is necessary that all medical
items (equipment and materials) utilised for the treatment of
patients are inherently safe for use so that the chance of
spreading diseases is kept as low as possible. Hospital acquired
infection is clearly the last thing either a patient or the
hospital wants.
[0009] The challenge therefore is that a steriliser operator must
minimise risk and make sure that the steriliser and sterilisation
cycle selected for use is suitable for the intended purpose.
Sterilisation is a controlled and monitored action and due to these
complexities and the requirement to achieve the desired Sterility
Assurance Level, international standards have been published;
typically ISO 17665 focussing on the effective validation of the
sterilisation of loads in a consistent, reproducible and recordable
manner and ISO 14937 focussing on the general requirements for
characterisation of a sterilisation agent and the development,
validation and routine control of a sterilisation process.
[0010] An unavoidable problem that faces sterilisation
practitioners is that the air in the room where the steriliser is
installed contains airborne particles, which may carry
microorganisms. Accordingly, when the sterile load is taken out of
the steriliser, it may be contaminated again. Additionally sterile
goods may be stored for quite some time before they are used.
Moreover, they are transported through the hospital to the place
they are to be used. It thus is probable that terminally sterile
loads/items will become re-contaminated by the time they are
used.
[0011] Consequently the items must be put in packaging to prevent
recontamination after sterilisation. To minimise recontamination
and augment the logistics and materials handling expediency of the
sterilisation process, the item(s) are usually pre-packaged. The
packaging heretofore typically include a fabric barrier typically,
muslin wraps, various paper wraps and non-woven wraps, or
alternatively laminated film pouches or sterilisation containers.
The wraps are typically secured by autoclavable tape which may
become detached during processing or in the handling of a package
leading to rejection of the package. An important feature of fabric
is its "breathability" or the ability of the fabric construction to
allow the passage of air and water vapour i.e. steam. Current
practices where breathable packaging is required to allow the
passage of the sterilant (water vapour/steam) in and out of the
package during the sterilisation process places huge demands on the
breathable packaging at the conclusion of the sterilisation process
to then act as a viral and liquid barrier to ensure impervious
protection of the terminally sterile load. The sterilised package
should be constructed so that it may be easily opened without the
packaging contaminating the contents.
[0012] Traditional sterilisation cycles may require up to 20
minutes of air-removal from the chamber and packages and
pre-heating of the load(s). Then sterilant is introduced until the
correct sterilisation parameters of pressure and temperature have
been established, to commence the sterilisation time duration
(typically 3.5-5 minutes @134 degrees Celsius of steam penetration
to facilitate sterilisation). Finally 20-40 minutes of vacuum
drying to remove the condensate from the chamber and packages. This
results in relatively long sterilisation cycles with limited
flexibility.
[0013] Sterile services technicians must have an understanding of
how to properly select and apply the correct wrap(s) for the
sterilisation method chosen. Technicians are also responsible for
quality assurance issues. They must assemble each package with
care, being observant not to tear or damage the wrap.
[0014] Each package is uniquely organised, depending upon content,
to promote the sterilisation process. Special attention must also
be given to how the steriliser is loaded. After sterilisation the
breathable packaging should provide an effective microbial barrier
for immediate use of the sterile items or facilitate a shelf
life.
[0015] It is essential that a packaging system with its content
meet the requirements in terms of sterility maintenance and
protection of its contents. That is why any packaging should be
validated in combination with the actual load and the sterilisation
process used.
[0016] It is clear to those skilled in the art of sterilisation of
an item(s) in a consistent, reproducible and recordable manner,
that this goal is made virtually impossible due to the multiple
variables faced by sterilisation practitioners daily predominantly
as a result of current technology and processes available to
sterilisation practitioners.
[0017] The applicants prior application published as WO2007/055595
discloses a sterilisation method and apparatus in which items to be
sterilised may be sterilised within a plastic bag whilst the
exterior of the sterilisation bag is maintained at atmospheric
pressure. Whilst effective, maintaining the exterior of the
sterilisation bag at atmospheric pressure puts mechanical demands
upon the sterilisation bag as it is evacuated and pressurised and
may not optimise the flow of fluid into, within and out of the bag.
The disclosure of this application is hereby incorporated by
reference.
[0018] It is the object of the invention to provide an improved
sterilisation method and sterilisation services apparatus or to at
least provide the public with a useful choice.
SUMMARY OF THE INVENTION
[0019] According to one broad aspect of the invention there is
provided a method of sterilising items including the steps of:
[0020] a. placing items to be sterilised into a puncture resistant
sealable vapour barrier sterilisation bag; [0021] b. performing
steam sterilisation under pressure via a conduit coupled to the bag
whilst maintaining a compensating pressure environment around the
exterior of the bag during steam sterilisation so as to reduce
mechanical stress on the bag; and [0022] c. sealing the bag at the
completion of sterilisation.
[0023] The sterilisation bag preferably has a large opening for
receiving items to be sterilised (preferably contained within a
perforated cage) which may be sealed before performing
sterilisation and a second opening for allowing the ingress and
egress of fluids into and out of the bag. In a further embodiment
one or more additional openings may also be provided connected to a
channel into the bag so that circulation of fluid within the bag
may be facilitated by supplying fluid via one opening and removing
it via the other. At the end of a sterilisation process the second
(and third if applicable) openings may be sealed.
[0024] The sterilisation bag is preferably evacuated before a
sterilisation process and the pressure around the bag is preferably
reduced below atmospheric pressure to facilitate effective
evacuation of the bag. During steam sterilisation the pressure
around the bag is maintained above atmospheric pressure to reduce
mechanical stress on the bag. During the sterilisation cycle an
external heat source (heated plates) may be applied around the bag
and in contact with the walls of the bag to assist the drying of
the sterile items.
[0025] According to a further aspect of the invention there is
provided a sterilisation services apparatus for sterilising the
contents of a sterilisation bag including: [0026] a. a pressure
compensating compartment having a sealable door that maintains a
compensating pressure environment around the exterior of a
sterilisation bag during steam sterilisation so as to reduce
mechanical stress on the bag; [0027] b. a fluid conduit adapted to
couple to an opening of a sterilisation bag during sterilisation
within the pressure compensating compartment; [0028] c. a steam
generator to supply steam to the bag via the conduit; [0029] d. a
bag sealing unit to seal the opening of the sterilisation bag, and
[0030] e. a vacuum pump for evacuating a sterilisation bag via the
conduit prior to steam sterilisation.
[0031] The sterilisation services apparatus may include heated
plates within the compensating pressure vessel to heat the exterior
of a sterilisation bag. Air may be introduced into the
sterilisation bag to facilitate drying of items within a bag.
[0032] The sterilisation services apparatus may include a clamp to
form a sealed connection between each conduit and each opening in a
sterilisation bag. A heat sealing bar and anvil may be provided to
seal the openings in a sterilisation bag when sterilisation has
been completed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The invention will now be described by way of example with
reference to the accompanying drawings in which:
[0034] FIG. 1 is a perspective view of a sterilisation services
apparatus and a sterilisation bag containing an item or items to be
sterilised, the bag being shown in place on a loading tray and
drawer arrangement
[0035] FIG. 2 is a perspective view of a reusable autoclavable
basket with a lid to be invested into a sterilisation bag,
[0036] FIG. 3 is a cross-sectional elevation view of the apparatus
shown in FIG. 1,
[0037] FIG. 4 is a more detailed view of the snorkel, clamping and
sealing mechanism and services socket arrangement, but with the
clamping and sealing mechanism shown in the rest position,
[0038] FIG. 5 is a perspective view of a heating plate for the base
of the packaging and side and top heating plates to heat the
exterior of the package within the pressure compensation
vessel,
[0039] FIG. 6 is a perspective view of the packaging and the drawer
loading tray, part of which has been removed in the interests of
clarity,
[0040] FIG. 7 is a schematic diagram of the electric and fluid
system of the embodiment shown in FIGS. 1 to 6;
[0041] FIG. 8 shows a perspective view of the packaging and the
loading tray-drawer according to an alternative embodiment,
[0042] FIG. 9 shows an enlarged view of the snorkel arrangement
employed in the embodiment in FIG. 8,
[0043] FIG. 10 shows a perspective view of the snorkel of the
embodiments shown in FIGS. 8 and 9 engaged with the bag,
[0044] FIG. 11 shows a bag utilised in the embodiment shown in
FIGS. 8 to 10, and
[0045] FIG. 12 shows a schematic diagram of the electric and fluid
system of the embodiment shown in FIGS. 8 to 11.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0046] In response to the challenges encountered by those of skill
in the art, from the following description it will be evident that
the requirements listed below are desirable:
Enabling Sterilisation
[0047] The packaging will allow air that is in the packaging to be
evacuated and the sterilant or sterilising agent to be introduced
to reach all surfaces of its content (items) via a conduit
(snorkel) communicating with an opening (mouth).
Compatible with the Sterilisation Process
[0048] The combination of the apparatus and packaging will be able
to withstand the conditions that occur during the sterilisation
process such as pressure changes, high temperature and
humidity.
Ensure Product Integrity and Patient Safety
[0049] The sterilisation bag/sterilisation process will not affect
the item(s) in any other way, which may affect the quality of the
item(s) or which might endanger the patient or process on which the
sterile item(s) will be used, subject to the item(s) to be
processed being rated for the sterilisation temperature and
pressure.
Maintaining Sterility
[0050] After taking the sealed and vacuum packed sterile
load/item(s) out of the apparatus it/they will remain sterile
during handling, transportation and storage until use, whilst
package seal integrity is intact.
Packaging Authentication
[0051] Authentication of the packaging prior to sterilisation of
item(s) is desirable to ensure an authenticated and validated
sterilisation bag is derived from tested and approved film to
facilitate the most appropriate functionality with respect to
sterilisation process, sealing integrity, handling, transportation
and shelf-life.
Tracking and Traceability
[0052] The apparatus and packing may desirably process individual
loads/trays with each load/tray incorporating a unique
identification code written to a RFID tag (attached to the load)
and captured in a database to facilitate data logging of process
parameters per individual package and to facilitate full tracking
and traceability of individual loads throughout its lifecycle.
Indicator
[0053] Transparent sealed packaging to facilitate visual
verification of sterilisation process indicators.
Facilitate Aseptic Opening and Presentation
[0054] When opening a sealed vacuum packed sterile load/item(s),
the packaging will facilitate aseptic opening and presentation.
This Implies:
[0055] simple opening when removing the sterile load/items from the
packaging, package opening will facilitate direct access to the
sterile load within the interior of the packaging, the design
incorporates an autoclavable perforated basket with lid (preferably
of stainless steel mesh construction or similar) that the item(s)
are placed in prior to insertion into the packaging (plastic bag).
Optionally the basket may be wrapped in a porous fabric/wrap to
further enhance aseptic release of the load in theatre of sterile
zone. Visible Indication that Packaged has been Opened or
Breached
[0056] Subjecting the package to a vacuum state whence sealed after
load sterility is achieved enables immediate visible indication of
package vacuum loss due to either a fault of seal integrity loss,
package integrity breach or package, opening under normal
controlled aseptic opening of terminally sterile package. In the
event that the package has lost its vacuum as a result of a failure
the package may be immediately be deemed contaminated and no longer
sterile.
[0057] The sterilisation services apparatus 9 in one embodiment
shown in FIG. 1 is seen to include a pressure compensating
compartment 10 including a loading processing tray 13 (capable of
interlocking in the pressure compensating compartment 10 when the
door 11 is in the closed position) into which is placed a plastic
sterilisation bag 8 (packaging), containing the load/basket of
item(s) 12 (see FIG. 2) to be processed,
[0058] The reusable autoclavable basket 12 in the preferred form is
a perforated basket with lid 12a (see FIG. 2) is dimensioned to be
inserted into the packaging 8. The basket 12 serves a number of
purposes--it: [0059] acts as a carrier basket for the many varied
load/items to be sterilised, [0060] facilitates ease of loading and
preferably results in uniform or standardised load packaging,
[0061] enhances the penetration of the sterilant to the items in
the basket due to the perforated design, [0062] assists the removal
of the sterilant at the end of the sterilisation cycle, [0063]
ensures and retains a shape for the packaging at the end of the
cycle when the sterile load is subjected to a vacuum and sealed and
minimises the probability of the load (sharp items) coming into
contact with the packaging, [0064] facilitates a uniform shape for
ease of stacking for storage and transportation and general
handling.
[0065] With correct loading of the load/items in the basket 12
there will potentially be less harm and damage to the load/items
during the entire materials handling/logistics cycle e.g. in a
hospital environment from the sterile department to theatre and
back.
[0066] The basket 12 will preferably be of a form that ensures the
packaging 8 is not damaged by sharp instruments, during the whole
vacuum-sealed life cycle of the sterile load.
[0067] When the packaging 8 is loaded onto the processing tray 13
of the compensator 10 it is correctly positioned by the door 11
when closed. The processing tray 13 is fitted with part of a clamp
14a (see FIG. 3) and sealing anvil 14b and process snorkel
arrangement 17 (see FIG. 4) including a conduit 17a for conveying
fluids to and from the bag.
[0068] The packaging 8 has an open mouth 7, opposing sides of which
will be laid over and under the conduit 17a. Once the packaging 8
is correctly positioned and the mouth 7 opening is routed over and
under the conduit 17a and across the clamp 14a and sealing anvil
14b. Then processing basket 12 is ready to positioned in the
pressure compensating compartment 10 (compensator) and the door 11
closed and interlocked in place and the sterilisation process can
take place.
[0069] The sterilisation services apparatus according to one
embodiment is envisaged to accommodate a load containing one basket
12 of half a sterilising unit [1/2StU=30 cm.times.15 cm.times.60 cm
(W.times.H.times.L)] per apparatus. This is by way of example and
the invention is not limited to this standard size.
[0070] The compensator 10 of apparatus 9 contains a heating plate
20. The combination of the processing tray base-members 19 (see
FIG. 6) and the heating plate 20 in the compensator 10 will ensure
that contact is made with the length and breadth of the bottom of
the package 8 as due to the positive pressure within the package
the package will be inflated onto the heating plate and side and
top heating plates 21b surrounding the exterior of the package,
resulting in the direct heating of any condensation within the
package that may settle in the bottom, sides or roof of the
package. In addition the heating plates 20 and 21b may assist
during the drying phase as it will apply direct heat to the package
whilst the vacuum is applied to dry the contents of the
package.
[0071] The heating plate 20 in the compensator 10 (see FIG. 3)
contains, in one form, electrical elements 21a (see FIG. 5).
[0072] A clamp 22a and seal bar 22b arrangement is housed in the
compensator 10 on one side of the compensator above the door 11
opening.
[0073] Referring now to FIG. 7 a schematic diagram of the
electrical and fluid system of the embodiment shown in FIGS. 1 to 6
is shown. The sterilisation services apparatus 9 includes a
controller 30 which receives information from sensors and inputs
from input devices and controls the operation of the sterilisation
services apparatus. A temperature sensor 31 provides controller 30
with information as to the temperature of fluids supplied to the
sterilisation bag via a nozzle 17a. Sensor 32 provides controller
30 with information as to the temperature of heating plates 20 and
21b. Pressure sensor 33 provides controller 30 with information as
to the pressure within compensator 10. Sensor 47 provides
controller 30 with the temperature within the compensator 10.
Sensor 48 located near snorkel 17 provides controller 30 with the
pressure within bag 8. A touch screen 34 enables user input to
controller 30 and display of outputs to a user via the screen. RFID
reader 35 reads RFID tags contained within a load to be processed
and provides the ID to controller 30. Controller 30 may write to an
RFID tag via RFID reader 35 also, if desired.
[0074] Storage device 36 provides data storage for controller 30.
Communications circuit 37 provides wire or wireless communications
between controller 30 and an external computer. Controller 30 may
control actuator 38 to raise and lower clamp 22a. Controller 30 may
supply power to sealing bar 22b to seal a sterilisation bag.
Controller 30 drives the elements 21a of heating plate 20 and 21b.
Controller 30 may supply fluid from steam generator 29 which may
supply steam to a bag 8 within compensator 10 via nozzle 17a.
Controller 30 may also drive pump 40 so that vacuum venturi 41
removes fluid from compensator 10 and returns it to cold water tank
42. Vacuum venturi 41 may also remove steam from bag 8 to condenser
43 to supply hot water to hot water tank 46 be returned via water
pump 39 to steam generator 29. Controller 30 also controls
compressor 44 to pressurise compensator 10. Pressure is reduced in
compensator 10 by actuating water pump 40 to drive vacuum venturi
41.
[0075] When the door 11 is closed, a start instruction is given to
a controller 30 via touch screen 34. Prior to processing a load
controller 30 may interrogate an RFID tag or other electronic
identification device within a package, to see if it has a valid
identification code. The identification code read by RFID reader is
35 supplied to controller 30 which may compare the code with its
internal memory 36 or with a remote database via communications
circuit 37. Controller 30 may allow further processing only if the
identification code is a valid identification code. If valid the
door seal 49 is actuated to seal the door and clamp 22a descends
(from the rest position shown in FIG. 3) under control of ram 25,
clamping the packaging 8 opening 7 around the intruding conduit 17a
by compressing the packaging and conduit between the upper clamp
22a and lower clamp 14a. This effectively clamps the packaging
about the snorkel 17 as shown in FIG. 3.
[0076] At the same time services are connected to the snorkel 17
via services supply socket 23 that mates with socket 23a of snorkel
17 as also shown in FIG. 4.
[0077] The processing basket 12 is located and held in position by
the door 11 within the closed and interlocked compensator 10 when
the start cycle instruction is given. Vacuum is then applied by
actuating water pump 40 to remove, via vacuum venturi 41 and
snorkel 17, air from within the packaging and load/items until the
required amount of air has been removed. The cycle pauses to test
for vacuum leaks and correct fitment of the packaging and clamp bar
arrangement about the snorkel 17.
[0078] When a vacuum is applied to the interior of the sealable
packaging 8 a deeper vacuum is simultaneously applied to the
exterior of the packaging in the compensator 10 until the desired
level of air removal within the package 8 and load has been
achieved, as monitored by sensors 33 & 48. This ensures that
the flexible sterilisation bag 8 does not collapse and restrict the
flow of fluid within the bag and via the conduit 17a.
[0079] The sterilant is then injected via the snorkel 17 into the
packaging 8 to sterilise the contents. Should the sterilant be
steam, an external steam generator/boiler 29 provides steam to
inside the packaging via the snorkel 17 as directed by the cycle
process and additionally the heating plates 20 and 21b act to
directly heat the condensate that has formed within the bottom of
the packaging turning it back to steam and reducing the volume
requirement for steam into the packaging (effectively recycling the
condensate).
[0080] During the introduction of sterilant to the interior of the
packaging 8 a counter pressure medium (in the preferable form of
compressed air) is simultaneously introduced into compensator 10 by
compressor 44 to increase the pressure in the compensator above
atmospheric pressure (typically about 2 atmospheres) so as to stop
the packaging 8 from blowing up under pressure and prevents seal
stress/rupture of packaging 8. This also maximises contact with the
heating plates 20 and 21b. The sides of the packaging 8 will be
restrained and the combination of packaging and compressed air on
the exterior of the packaging 8 will hold the steam pressure within
the packaging 8 at the process temperature (usually 134 degrees.
Celsius) until the predetermined sterilisation parameters have been
fulfilled. Sensor 31 provides information as to the temperature of
steam supplied to packaging 8 and sensor 48 provides information as
to the pressure within the bag so that controller 30 can monitor
sterilisation conditions and control operation accordingly.
[0081] The sterilant is then removed from the interior of package 8
by gradually applying a vacuum to the interior of the package 8 to
evacuate the sterilant/steam and facilitate drying of the load
whilst simultaneously applying a vacuum to the exterior of the
package 8 during this phase to minimise and control the vacuum
crush effect on the load in the package 8. Vacuum is applied by
driving pump 40 by which via vacuum venturi 41 evacuates
compensator 10 and the interior of bag 8 (via condenser 43) whilst
maintaining a heated compensating pressure to the exterior of the
packaging by means of the heating plate 20 and heating source 21b
to ensure thorough drying of the interior of the bag and items to
be sterilised (the load).
[0082] Finally as a possible embodiment a drying medium, such as
dry, filtered air 45 or superheated steam, may be introduced into
the packaging 8 to dry items in the packaging whilst the vacuum is
simultaneously controlled on the exterior of the package 8 in the
compensator 10.
[0083] Finally a vacuum may be applied and the packaging 8 sealed
while under partial vacuum via the seal bar 22b. The upper seal bar
22b contains the sealing element which heat seals the packaging 8
just behind the clamp 14a, 14b and conduit 17a by compressing (via
further operation of cylinder 26) the seal bar 22b down on to the
lower seal anvil 14b. The package is thus sealed, following which
the seal bar 22b and clamp bar 22a are returned to the raised open
position (FIG. 4), the compensator 10 is returned to atmospheric
pressure and the door 11 interlock released. The compensator 10 can
thus be opened and the sterilised packaging 8 is presented for
removal. Due to the vacuum sealing it will be immediately obvious
if the packaging integrity is intact by visual inspection when a
user comes to use the vacuum sealed packaging (i.e. the packaging
should be forced tightly against cage 12).
[0084] Referring now to FIGS. 8 to 12 an alternative embodiment is
shown in which the snorkel 53 has dual nozzles 50 and 51 to allow
the circulation of filtered air or superheated steam within bag 52.
Like elements to those shown in FIGS. 1 to 7 have been given the
same numbering. The modified embodiment is shown in FIGS. 8 to 12
utilises dual nozzles 50 and 51, the bag construction shown in FIG.
11 and a different fluid flow arrangement as shown in FIG. 12. Dual
nozzles 50 and 51 are employed in this embodiment to facilitate
improved drying of the load prior to sealing. The bag shown in FIG.
11 is divided into a channel 57 and a bag interior 58 by fusing the
walls of the bags together by heat sealing along line 59. Inlet
nozzle 51 engages with opening 56 to supply fluid to channel 57.
This is introduced to the interior of the bag 58, circulated
through the bag then removed via opening 55 which engages the
nozzle 50.
[0085] Operation is as per the previous embodiment except that
during the drying stage either heated air from air filter 45 is
heated and supplied via nozzle 51 to opening 56 or steam vapour is
removed from bag via a fan/pump so that super heated steam is
supplied by nozzle 51 to opening 56. With heated air a vacuum is
applied to opening 55 via nozzle 50 with extracted fluid condensed
by condenser 43. This embodiment offers improved drying due to the
circulation of fluid within the bag.
[0086] The apparatus capacity is expected to be designed along the
capacities consisting of Sterile Units (StU), either in portions or
multiples thereof from small dental units to large `banks` of
apparatus with each individual apparatus incorporating all its
services (vacuum, steam) and controller.
[0087] It is feasible that a single computer controller could
manage a bank of the sterilising apparatus 9 to replace the
traditional multi-load sterilisers in use today. This means that
individual items or loads could be prioritised to suit
production/user requirements. The potential to incorporate,
automated loading and unloading systems is also envisaged due to
the versatility of the invention.
[0088] The package 8 will need to be made to required
specifications, specific to this application. The package (and
film) will be impervious and non-porous to facilitate the
parameters of steam sterilisation and be able to hold a vacuum for
a prolonged period under sealed conditions. Means may be
incorporated, in the package 8 and apparatus 9 to enable the
apparatus 9 to either accept or reject a package 8, through a
process of authentication and/or unique number marking.
[0089] The package 8 and basket 12 in conjunction with the
apparatus 9 may incorporate a unique number marking system and/or
radio frequency identification system (RFID) to facilitate data
capture at tray 12 level of sterilisation parameters and facilitate
full tracking and traceability with other software systems.
[0090] The instrument basket and lid 12 & 12a will preferably
be constructed of stainless steel mesh or aluminium or suitable
substitute material. As disclosed above the basket and lid 12/12a
will contain the items and maintain the packages shape around the
carrier under vacuum thereby preventing damage or puncturing of the
package's wall integrity from the internal items to be sterilised.
The basket 12 may be fitted with an insert or adjustable/variable
clamp/partitioning to best accommodate the items.
[0091] Controller 30 may incorporate control hardware and software
that enables real time control of the process parameters
irrespective of the load configuration. The benefit of real time
control, monitoring and data capture of sterilisation parameters in
the interior of the package 8 at individual tray level is that the
validation of cycle parameters versus load variability will no
longer be a challenge.
[0092] The apparatus 9 may be fitted with a printer to print the
cycle parameters and all other relevant data as deemed necessary.
This will result in a number of process, logistic, materials
handling, tracking and quality control benefits. Thus data may also
be written to an RFID tag within packaging 8 or communicated via
communication circuit 37 to a remote database.
[0093] The packaging 8 and basket 12/12a may preferably accommodate
a clearly visible sterilisation monitoring device or indicator
within the packaging 8 to indicate the status of the load and
independently confirm whether the items/load is sterile or not.
[0094] The combination of apparatus 9, package 8 and process of the
invention provides an inventive new method to achieve sterilisation
more efficiently with numerous operational and clinical
benefits.
[0095] The design incorporates energy efficiencies resulting in
substantially reduced power and sterilant usage with shorter
overall cycle times. Based on the international standard sterile
unit size(s), the package 8 is loaded via the standardised
processing basket 13 thereby facilitating and promoting
standardisation of individual load dynamics.
[0096] The ergonomics of the apparatus 9, stand-alone design
incorporating all the services (vacuum, steam generator, pure water
reservoir, automatic controller etc.) and relative small footprint
facilitates substantial floor space, operational and capital
expenditure savings. The front loading or optional pass-through
double ended design allows a seamless integration with modern
appliance fitments.
[0097] The apparatus 9 and package 8 offer a means to replace the
challenges presented by existing packaging practices and/or storage
containers and offers extended product shelf life with immediate
visible indication of contamination or barrier failure. This
process offers a substantially quicker full sterilisation
processing time opening numerous opportunities for quick processing
of items requiring a short turnaround time. In addition the
apparatus does not require a large inefficient pressure vessel and
associated steam generator therefore offering substantial total
cost of ownership benefits and reduces the impact on the
environment.
[0098] The sterilisation medium or sterilant is not limited to
steam only as the principles incorporated in the invention can be
universally applicable to other mediums currently used in low
temperature sterilisers.
[0099] A further modification is that rather than vacuum seal the
packaging the packaging could be bought back to atmospheric
pressure and sealed. Other possibilities are to pressurise or gas
flush the packaging and then seal the packaging.
[0100] The apparatus shall not be limited to the preferred
embodiment and may take the form of a top loader, double ended pass
through or auto loading device, or multiples of the apparatus. In
the preferred embodiment the apparatus shall process a single load
and shall not be limited to the preferred embodiment and may take
the form of processing multiple loads in a single apparatus.
[0101] The invention as described herein is open to modification as
will be appreciated by those skilled in the art. For example,
rather than perform as a steriliser the apparatus could be used as
a retort or food cooking apparatus but not limited to only these
applications.
[0102] Other modifications and improvements to the invention will
be apparent to the skilled person and will fall within the scope of
the invention as it is intended.
[0103] It is believed that the process described overcomes most
shortcomings of current practices and procedures due to the fact
that the load is placed into the sealable non-porous, impervious
package for the duration of the complete sterilisation process and
then the impervious packaged is hermetically sealed. The vacuum
packed terminally sterile load remains safely within the non-porous
impervious package offering viral and liquid barrier protection.
Therefore the probability of recontamination is minimised whilst
the package seal integrity is maintained.
[0104] The combination of an innovative apparatus and sealable
package in effect replaces the necessity for an inefficient
conventional steriliser and breathable barrier technologies.
[0105] Due to the process of sterilisation occurring within the
confines of the package in direct contact with the load, not a
large spacious chamber containing the load(s) plus the unutilised
chamber volume, the resultant services (steam/vacuum) requirements,
are significantly reduced thereby offering increased processing
efficiencies and vastly improved direct control.
[0106] Use of a pressure compensating compartment minimises the
demands placed on the package with respect to design, film, seal
strength and clamp pressure around the mouth and snorkel and by
ensuring a marginally lower pressure on the exterior of the package
during the sterilant phase resulting in a package under positive
pressure thereby reducing the possibility of non-sterile ingression
from the exterior similarly during the vacuum phase(s) a deeper
vacuum is pulled on the exterior of the package than within the
interior of the package reducing the possibility of non-sterile
ingression.
[0107] Vacuum sealing the sterilisation bag under vacuum at the end
of the sterilisation process results in an impervious non-porous
package offering a pre-determined shelf life and immediate visible
means of detection should the package seal be compromised.
[0108] The use of identification features allows bag validation and
the stopping of the sterilisation process should there be a failure
at any stage. The use of a unique identification code for each bag
allows bag authentication and traceability at tray level as well as
recordal of each stage of the sterilisation process for a specific
load.
[0109] The process of the present invention will remove air from
directly inside the packaging within seconds/minutes whilst
pre-heating the load, sterilisation parameters of pressure and time
will adhere to international recognised standards (typically 3.5-5
minutes @134 degrees Celsius of steam penetration to facilitate
sterilisation) followed by the drying phase by means of removing
the majority of the steam/condensate through pulling a vacuum in
the package whilst the package is located within the heating
plates, drying will be facilitated within minutes. It is envisaged
that most sterilisation cycle time(s) may be reduced by more than
50%, subject to the load mass.
[0110] The sterilised load (items) will be vacuum sealed in the
packaging at the end of the sterilisation cycle and it is believed
that the invention will result in less likelihood of wet load
problems due to direct heat transfer of heat from the heating plate
during the drying phase. Nevertheless due to non-use of wrap (or
optional inner very porous wrap purely for enhancement of aseptic
release) vacuum drying efficiency will be greatly enhanced,
notwithstanding this fact there will be no requirement for the load
to be completely dry as the packaging barrier ensuring sterility
retention will be impervious and non-porous. The shelf life of a
sterile load(s) shall be controllable, monitor friendly and
possibly significantly extended and may very well be
indefinite.
[0111] It is anticipated that the method of sterilisation according
to the invention will provide substantial efficiencies and cost
savings in the sterilisation process model. The process of the
present invention will remove air from directly inside the
packaging within seconds/minutes whilst pre-heating the load,
sterilisation parameters of pressure and time will adhere to
international recognised standards (typically 3.5-5 minutes @134
degrees Celsius of steam penetration to facilitate sterilisation)
followed by the drying phase by means of removing the majority of
the steam/condensate through pulling a vacuum in the package whilst
the package is located on the heating plate, drying will be
facilitated within minutes. It is envisaged that most sterilisation
cycle time(s) may be reduced by more than 50%, subject to the load
mass.
[0112] While the present invention has been illustrated by the
description of the embodiments thereof, and while the embodiments
have been described in detail, it is not the intention of the
Applicant to restrict or in any way limit the scope of the appended
claims to such detail. Additional advantages and modifications will
readily appear to those skilled in the art. Therefore, the
invention in its broader aspects is not limited to the specific
details, representative apparatus and method, and illustrative
examples shown and described. Accordingly, departures may be made
from such details without departure from the spirit or scope of the
Applicant's general inventive concept.
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