U.S. patent number 3,875,927 [Application Number 05/377,195] was granted by the patent office on 1975-04-08 for isolators.
This patent grant is currently assigned to National Research Development Corporation. Invention is credited to Philip Charles Trexler.
United States Patent |
3,875,927 |
Trexler |
April 8, 1975 |
Isolators
Abstract
An isolator comprises an enclosure member adapted to provide a
controlled microbiological environment and having a transfer port
for passage of objects into and out of the enclosure member. The
transfer port comprises a conduit communicating at one end with the
interior of the enclosure member, and having its other end external
to the enclosure member, and air supply means communicating with
the conduit to direct a flow of sterilised air over the inner
surface of the conduit. Preferably the conduit has an inner wall
and an outer wall spaced apart over at least part of the conduit,
and there is provided an array of openings distributed over the
inner surface of the conduit.
Inventors: |
Trexler; Philip Charles
(Sindlesham, EN) |
Assignee: |
National Research Development
Corporation (London, EN)
|
Family
ID: |
10337709 |
Appl.
No.: |
05/377,195 |
Filed: |
July 9, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Jul 11, 1972 [GB] |
|
|
32380/72 |
|
Current U.S.
Class: |
600/21; 312/1;
454/188; 55/DIG.29; 454/187 |
Current CPC
Class: |
B25J
21/02 (20130101); B01L 1/04 (20130101); Y10S
55/29 (20130101) |
Current International
Class: |
B25J
21/02 (20060101); B25J 21/00 (20060101); B01L
1/04 (20060101); B01L 1/00 (20060101); A61b
019/00 () |
Field of
Search: |
;128/1B,191A,132
;98/36,115LH ;23/259 ;34/242 ;312/1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Dunne; G. F.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Claims
I claim:
1. An isolator comprising:
an isolator enclosure member;
a transfer conduit for passage of objects into said isolator
enclosure member, said conduit communicating at one end with the
interior of said enclosure member and having its other end external
to said enclosure member, and at least part of said conduit having
inner and outer walls spaced apart from each other when the conduit
is in use;
air supply means for supplying sterilized air to the space between
said inner and outer walls of said conduit; said inner wall of said
conduit defining an array of openings through said inner wall for
directing a flow of sterilized air over that part of the inner
surface of said conduit which adjoins said external end of said
conduit in a flow pattern for preventing entry of unsterilized air
into said conduit; and
a closure member situated within said enclosure member for closing
off said conduit from the interior of said enclosure member when
said conduit is not in use for passage of objects; said closure
member comprising a further conduit of flexible material extending
from the first conduit into the interior of the enclosure
member.
2. An isolator comprising:
an isolator enclosure member of a size such as to allow surgical
operations or other medical activities to be carried out within the
enclosure member;
a transfer conduit for passage of surgical instrument packs and
other sterilized objects into said isolator enclosure member, said
conduit communicating at one end with the interior of said
enclosure member and having its other end external to said
enclosure member, said conduit having a length along the axis of
said conduit at least equal to half the width of said conduit at
its narrowest part, and at least part of said conduit having inner
and outer walls spaced apart from each other when the conduit is in
use;
air supply means for supplying sterilized air to the space between
said inner and outer walls of said conduit;
said inner wall of said conduit defining an array of openings
through said inner wall for directing sterilized air from said
space between said walls into said conduit, and said openings being
arranged in an array which continues along the inner surface of
said conduit to an extent sufficient for providing an overall
outward flow of sterilized air over said inner surface of said
conduit for preventing entry of unsterilized air unto said conduit
by turbulence effects at the edge of said external end of said
conduit.
3. An isolator according to claim 2 wherein the conduit walls are
made of flexible material, and the inner and outer walls are joined
together at intervals to provide inflatable ribs such that the
conduit is at least partially self-supporting in an open
configuration when inflated through the air inlet.
4. An isolator according to claim 2 wherein the outer wall of the
conduit is formed of rigid material.
5. An isolator according to claim 4 wherein the inner wall of the
conduit is formed of rigid material.
6. An isolator according to claim 2, wherein the inner wall of the
conduit is made of woven fabric, the said array of openings being
provided by the intersticies in the woven fabric.
7. An isolator according to claim 6 wherein the said woven fabric
is canvas.
8. An isolator according to claim 2 including a layer of air
filtering material positioned between the inner and outer walls of
the conduit, and contiguous with the inner wall of the conduit.
9. An isolator comprising:
flexible, inflatable, isolator enclosure member of a size such as
to allow surgical operations or other medical activities to be
carried out within the enclosure member;
a transfer conduit for passage of surgical instrument packs and
other sterilized objects into said isolator enclosure member, said
conduit communicating at one end with the interior of said
enclosure member and having its other end external to said
enclosure member, said conduit having a length along the axis of
said conduit at least equal to half the width of said conduit at
its narrowest part, and at least part of said conduit having inner
and outer walls spaced apart from each other when the conduit is in
use;
a closure member situated within said enclosure member for closing
off said conduit from the interior of said enclosure member when
said conduit is not in use for passage of objects; and
air supply means for supplying sterilized air to the space between
said inner and outer walls of said conduit;
said inner wall of said conduit defining an array of openings
through said inner wall for directing sterilized air from said
space between said walls into said conduit, and said openings being
arranged in an array which continues along the inner surface of
said conduit to an extent sufficient for providing an overall
outward flow of sterilized air into said conduit by turbulence
effects at the edge of said external end of said conduit.
10. A isolator according to claim 9 in which the closure member
comprises a flexible sheet member of synthetic plastic material and
a weighting member attached to the sheet member for holding the
sheet member across the inner end of the transfer conduit.
11. A transfer apparatus for an isolator comprising:
a transfer conduit for passage of surgical instrument packs and
other sterilized objects into an isolator enclosure member, said
conduit having a length along the axis of said conduit at least
equal to half the width of said conduit at its narrowest part, and
at least part of said conduit having inner and outer walls spaced
apart from each other when the conduit is in use; and
air supply means for supplying sterilized air to the space between
said inner and outer walls of said conduit;
said inner wall of said conduit defining an array of openings
through said inner wall for directing sterilized air from said
space between said walls into said conduit, and said openings being
arranged in an array which continues along the inner surface of
said conduit to an extent sufficient for providing an overall
outward flow of sterilized air over said inner surface of said
conduit for preventing entry of unsterilized air into said conduit
by turbulence effects at the edge of said end of said conduit.
12. A transfer apparatus according to claim 11 wherein the conduit
walls are made of flexible material, and the inner and outer walls
are joined together at intervals to provide inflatable ribs such
that the conduit is at least partially self-supporting in an open
configuration when inflated through the air inlet.
13. A transfer apparatus according to claim 11 wherein the inner
and outer walls of the conduit are made of flexible synthetic
plastics material.
14. A transfer apparatus according to claim 11 wherein the outer
wall of the conduit is formed of rigid material.
15. A transfer apparatus according to claim 11 wherein the inner
wall of the conduit is formed of rigid material.
16. A transfer apparatus according to claim 11 wherein the inner
wall of the conduit is made of woven fabric, the said array of
openings being provided by the intersticies in the woven
fabric.
17. A transfer apparatus according to claim 11 wherein the said
woven fabric is canvas.
18. A transfer apparatus according to claim 11 including a layer of
air filtering material positioned between the inner and outer walls
of the conduit and continguous with the inner wall of the conduit.
Description
The present invention is concerned with improvements in and
relating to isolators.
The invention is concerned with enclosures which have become known
as isolators and which are used for the handling of laboratory
animals and human patients under gnotobiotic conditions. An
isolator commonly consists of a flexible bag of synthetic plastic
material forming an enclosure which is continuously vented with
germ free air, and commonly maintained at a small positive air
pressure with respect to the ambient atmosphere. Commonly the
isolators are in disposable form, being provided presterilised for
use on one occasion only.
In such as isolator, the main weakness in the isolation of the
system lies in the arrangements for introducing and removing
material and instruments into and from the enclosure, as these
arrangements usually involve the necessity of breaking the boundary
of the environment.
It is an object of the present invention to provide improved
arrangements for introducing and removing objects to and from an
isolator.
According to the present invention there is provided an isolator
comprising an enclosure member and having a transfer port for
passage of objects into and out of the enclosure member, the
transfer port comprising conduit communicating at one end with the
interior of the enclosure member, and having its other end external
to the enclosure member, and air supply means communicating with
the conduit and arranged of direct a flow of sterilised air over
that part of the inner surface of the conduit which adjoins the
external end of the conduit in a flow pattern such as substantially
to prevent in operation entry of unsterilised air into the
conduit.
By an isolator is meant apparatus including or consisting of an
enclosure member adapted to provide a controlled microbiological
environment for example for medical or experimental purposes. Such
an enclosure will commonly have means for handling objects within
the enclosure member without breaking the microbiological isolation
of the enclosure. The term enclosure member includes a partial
enclosure member, for example an open bottomed enclosure member
adapted to being secured to the body of a patient to provide in
operation a complete enclosure the base of which is constituted by
part of the body of the patient.
The air supply means may include an array of openings distributed
over the inner surface of the conduit. In one arrangement the
conduit has an inner wall and an outer wall spaced apart over at
least part of the conduit, and the air supply means includes an air
inlet in the outer wall of the conduit for supplying air to the
space between the inner and outer walls of the conduit.
In a preferred arrangement according to the invention an isolator
comprises a flexible walled enclosure member having an air inlet
for supplying air to inflate the enclosure member in use and having
a transfer port for passage of objects into and out of the
enclosure member, the transfer port comprising a conduit
communicating at one end with the interior of the enclosure member,
and having its other end external to the enclosure member, the
conduit being made of flexible material and having an inner wall
and an outer wall spaced apart over at least part of the conduit,
an air inlet in the outer wall of the conduit for supplying air to
the space between the inner and outer walls of the conduit, and an
array of openings in the inner wall of the conduit for directing a
flow of sterilised air over at least part of the inner surface of
the conduit in a flow pattern such as substantially to prevent in
operation entry of unsterilised air into the conduit.
The conduit walls may be made of flexible material, with the inner
and outer walls joined together at intervals to provide inflatable
ribs such that the conduit is at least partially self-supporting in
an open configuration when inflated through the air inlet.
Thus the size of the openings in relation to the volume of the
space between the walls of the conduit may be such that in
operation application to the space of air above ambient pressure
inflates the conduit and supports the conduit in an open position.
The air chamber may comprise a plurality of ribs aligned along the
length of the conduit, and may include circular ribs passing around
the ends of the conduit.
In some arrangements according to the invention, either the inner
or outer wall of the conduit may be formed of rigid material, the
other wall being flexible, or both the inner and outer walls of the
conduit may be formed of rigid material.
For example, where the conduit walls are flexible, the whole
transfer port may conveniently be made as a disposable item, being
supplied in sterile condition for use on one occasion only.
Alternatively, the conduit may be wholly or partly a rigid
structure, and may be a reusable item to be coupled to a disposable
isolator.
The inner wall of the conduit may be made of woven fabric, the said
array of openings being provided by the intersticies in the woven
fabric. The said woven fabric may be canvas.
There may be provided a layer of air filtering material positioned
between the inner and outer walls of the conduit and contiguous
with the inner wall of the conduit.
There may be provided a closure member situated within the
enclosure for closing off temporarily the conduit member from the
interior of the enclosure member. The closure member may comprise a
further conduit of flexible material extending from the first
conduit into the inside of the enclosure member. Alternatively, the
closure member may comprise a flexible sheet or material hanging
across the opening in the isolator wall, and biassed to close the
opening by a weight attached to the bottom of the sheet.
Alternatively the opening may be closed by flaps with closure means
such as a zip fastener.
The invention has particular usefulness where the isolator is a
disposable isolator, the enclosure member being made of flexible
synthetic plastics material, although the conduit may be made of
rigid material.
There is also provided in accordance with the present invention a
transfer port for an isolator comprising a conduit having one end
adapted to communicate with the interior of an isolator and another
end adapted to be positioned exterior to the isolator to allow
objects to be passed through the conduit into and out of the
isolator, and air supply means communicating with the conduit and
arranged to direct a flow of sterilised air over that part of the
inner surface of the conduit which adjoins the exterior end of the
conduit in a flow pattern such as substantially to prevent in
operation entry of unsterilised air into the conduit.
There is further provided in accordance with the present invention
a transfer port for an isolator comprising a conduit having one end
adapted to communicate with the interior of an isolator, the
conduit having an inner wall and an outer wall spaced apart over at
least part of the conduit, an air inlet in the outer wall of the
conduit for supplying air to the space between the inner and outer
walls of the conduit, and an array of openings in the inner wall of
the conduit for directing a flow of sterilised air over at least
part of the inner surface of the conduit in a flow pattern such as
substantially to prevent in operation entry of unsterilised air
into the conduit.
Embodiments of the invention will now be described by way of
example with reference to the accompanying drawings in which:
FIG. 1 is a perspective view of a transfer port attached to the
boundary wall of an isolator, and embodying the present
invention;
FIG. 2 is a longitudinal section of the transfer port of FIG. 1
taken along the lines II -- II;
FIG. 3 is a perspective view of a modified transfer port embodying
the invention; and
FIG. 4 is a longitudinal section, partly diagrammatic, of the
transfer port of FIG. 3, taken along the lines IV -- IV in FIG.
3.
Referring to FIGS. 1 and 2, there is shown a part of a wall 11 of
an isolator 10 comprising a flexible enclosure member of synthetic
plastics material, such as polyvinylchloride, inflated with
sterilised air pumped into the enclosure at a pressure slightly
above ambient pressure. Secured to the wall 11 is a transfer port
12 which in the embodiment shown consists of an entry port.
The entry port comprises a conduit 13 having one end 14 sealed
around an opening 15 in the wall 11 by a thermo-weld at 16. The
opening 15 of the wall 11 is located by a rigid metal ring 17 which
in practice is supported by a metal frame of the isolator, not
shown in FIG. 1. The junction of the conduit end 14 and the wall 11
at the weld 16 is secured to the rigid ring 17 by adhesive tape
18.
The conduit 13 comprises a substantially cylindrical passageway or
sleeve of flexible synthetic plastics material having inner and
outer walls 19 and 20 respectively. At the attached end 14 of the
conduit the two walls 19 and 20 lie flat together, and the walls
are welded together along a number of weld lines, for example shown
at 21, in a pattern such as to define a series of longitudinal ribs
22 and a circular end rib 23 running around the free end of the
conduit 13. The ribs 22 and 23 are in communication with each other
and are in communication with an air input nozzle 24 which is
coupled by way of a sterilizing filter 25 to a pipe 26 leading from
an air compressor not shown.
It will be appreciated that all connections and pipes down stream
of the filter need to be carefully sterilised before connection,
and to be maintained in a sterile condition during operation of the
transfer port. In alternative arrangements, the air may be fed
unsterilized to the transfer port, and there may be provided a
filter located within, or fixed to, the transfer port for filtering
the air before it emerges from the openings in the inner wall of
the transfer port.
In operation, air is pumped through the air input 24 at a pressure
slightly above ambient atmospheric pressure and inflates the ribs
22 and end ring 23 so as to maintain the conduit in an open
position. The end walls 19 and 20 in the areas between the ribs 22
lie flat against each other and are not inflated. The weight of the
upper wall of the conduit causes the circular end rib 23 to adopt a
slightly oval configuration as shown.
Distributed over inner surface of the conduit 13 is an array of
openings comprising a plurality of pin-prick apertures 27
distributed along the ribs 22 and 23, for directing a flow of
sterilised air over the inner surface of the conduit 13. These
apertures are so positioned, and the pressure of the air from the
pump is so arranged, that the air flowing over the inner surface of
the conduit 13 flows in a flow pattern such as substantially to
prevent entry of unsterilised air into the isolator 10. That is to
say that the air pumped through the apertures 27 flows outwardly
along the inner surface of the conduit 13 and thence in a cone of
sterilised air leaving at the end ring 23. It will be appreciated
that as the isolator 10 is maintained at a pressure slightly above
ambient pressure, some air may leak from the isolator 10 through
the conduit 13.
By way of example only, the conduit 13 may be in the region of two
feet along the length of the conduit and the opening 15 may be in
the region of 18 inches in diameter. The air holes 27 may be
positioned between one-fourth and one-half inch apart.
As shown in FIG. 2, a flap of flexible synthetic plastic material
28 is secured by welding along a weld line 29 above the opening 15,
and is weighted by a metal bar 30 so as to hang across the opening
15. In combination with the slight positive pressure within the
isolator and the flow of air from the apertures 27, the weight 30
maintains the flap 28 in a good seal with the wall 11 around the
opening 15. The flap is moved to one side when it is desired to
pass objects into the isolator 10 through the conduit 13. As an
alternative to the flap 28, a loose inner conduit extending into
the isolator from the opening 15 may be provided and may be sealed,
for example by a plastic zip fastener (not shown). This inner
conduit (shown in s different arrangement in FIG. 4 described
hereinafter) is entirely within the enclosure member of the
isolator and is operated from within the isolator by manipulating
means such as rubber gloves and sleeves extending into the
isolator, and integral with the wall thereof. Such gloves
conventionally extend the length of the operator's arms and allow
an operator to stand outside the isolator but to extend his arms
(in the gloves) within the enclosure to manipulate objects therein.
Thus the flap 28 can be opened and closed without breaking the
isolation of the enclosure.
The apparatus is particularly useful in providing a method for
introducing sterile supplies into a surgical isolator, for example
for introducing the sterile surgical instrument pack which is
commonly available in operating theatres. This pack consists of a
tray of cardboard, metal or plastic containing the instruments to
be used and surrounded by one or more wraps of paper or cloth.
The air emerging from the entry port provides a cone of sterile air
in which the outer wrap of the sterile package can be partially
removed by the circulating nurse. The scrub nurse, using the gloves
and sleeves which are continuous with the wall of the isolator
enclosure, reaches through the opening 15 from the inside of the
isolator and grasps the sterile end of the package, the non-sterile
end of the package being held by the circulating nurse whose arms
and hands are pushed into the conduit 13 from the end outside the
isolator. The scrub nurse reaching into the conduit from the
isolator end then introduces the sterile package into the isolator
while the circulating nurse removes the outer protecting wrap from
the conduit.
In practice the conduit may be either disposable and form part of
the isolator for sterilisation purposes, or may be a separate item
which can be sterilised in an autoclave by the hospital staff. The
isolator itself is sterilised by gamma-radiation, as is also the
conduit when permanently attached to the isolator.
A number of modifications may be made to the apparatus shown in the
figures. For example the air arranged to flow over at least part of
the inner surface of the conduit may be arranged to flow from
inside the isolator 10, being directed in the appropriate flow
pattern by channels (not shown) in the opening 15.
In another modification, means for distributing the air from the
ribs 22 may be provided in the form of an inner cloth wall (not
shown) in FIGS. 1 and 2 extending from the ring 23 to the weld line
21, and serving the purpose of distributing evenly the air passing
into the conduit 13. One preferred embodiment of a port according
to the invention in which an inner cloth wall is used to distribute
the air evenly will now be described with reference to FIGS. 3 and
4. In these figures, those elements which correspond to elements
shown in FIGS. 1 and 2 will be referred to by like reference
numerals.
As can be seen in FIGS. 3 and 4 the general configuration of the
transfer port 12 is similar to that of FIGS. 1 and 2. The transfer
port 12 is partially supported by rings 31 and 32 coupling a frame
33 to eyelets 34 attached to the isolator wall 11, or alternatively
(or in addition) by a fold of plastic 35 suspending the port 12,
from a rod 36. The port shown in FIGS. 3 and 4 may, for example, be
shorter than that of FIGS. 1 and 2, for example 1ft long along the
conduit. Other differences in layout, relative to the embodiments
of FIGS. 1 and 2, include the provision of a rear circular rib 23',
and two weld lines 21' extending through the ribs 23 and 23' to
divide the upper and lower sets of ribs. The upper and lower sets
of ribs are supplied with sterilised air from an inlet chamber 37
coupled to the pipe 24 and communicating with the ribs 21, 23 and
23' through two inlet ports 38 and 39. The inlet chamber 37 also
supplies air to the main enclosure member of the isolator 10
through an inlet port 40.
The main functional modification of the transfer port of FIGS. 3
and 4 is that the inner wall 19 is formed of canvas in place of the
synthetic plastics material of FIGS. 1 and 2. The outer wall 20
continues to be made of synthetic plastics material and is bonded
to the canvas at the weld lines in the same manner as when both
walls were made of synthetic plastics.
In FIG. 4, the inner edges of the walls 19 and 20 at the isolator
end of the conduit 13 are shown diagrammatically in exploded form.
In practice, in this example, the edges of the walls 19 and 20, the
further conduit 41, and the opening 15 in the wall 11, are all
welded together at a single weld line produced by heat and pressure
welding of the plastic material.
The advantage of the inner canvas wall is that the openings for the
sterilised air are far more numerous than with the perforated
synthetic plastics material. Because of the relative stiffness of
the canvas, the ribs 22 can made much wider while providing a
relatively smooth curve to the inner surface of the conduit. As the
ribs 22 are wider, almost the whole inner surface of the conduit 13
is a "live" surface, in that it passes sterilised air. This
produces an even flow of air over the inner surface of the
conduit.
As has been mentioned previously, the embodiment of FIGS. 3 and 4
includes a further conduit 41 of single walled synthetic plastics
material. This further conduit 41 is a continuation of the conduit
13, and extends inside the enclosure member of the isolator 10. The
conduit 41 serves to shut-off the conduit 13 from the enclosure
when the conduit 13 is not in use for transferring objects.
As has been mentioned in connection with the embodiments of FIGS. 1
and 2, the air supplied to the transfer port may initially be
unsterilised and may be sterilised by passing through a filter
contained in the transfer port. In one convenient arrangement, an
internal filter may be provided in the transfer port by a glass
wool filter mat positioned between the inner and outer walls of the
transfer port and formed on the interior surface of the canvas
inner wall of the transfer port. Thus the air circulating between
the filter mat and the outer wall of the transfer port may be
unsterile, but is rendered sterile by passing through the glass
wool filter mat to the openings in the canvas wall.
In some arrangements embodying the invention, the outer wall of the
conduit, for example the outer wall 20 in FIGS. 3 and 4, may be
made of rigid material such as rigid synthetic plastic material the
configuration being otherwise as shown in the figures.
Alternatively, in some arrangements, the conduit may be self
supporting by virture of the rigid outer wall and the rib
configuration may be dispensed with. In both cases, the inner wall
19 may remain of canvas or perforated synthetic plastics material,
or the inner wall may also be made of rigid material.
* * * * *