U.S. patent number 3,680,560 [Application Number 04/778,963] was granted by the patent office on 1972-08-01 for vacuum drainage collecting apparatus with disposable liner.
This patent grant is currently assigned to Le Voy's Inc.. Invention is credited to Karl A. Pannier, Jr., Gordon S. Reynolds, James L. Sorenson.
United States Patent |
3,680,560 |
Pannier, Jr. , et
al. |
August 1, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
VACUUM DRAINAGE COLLECTING APPARATUS WITH DISPOSABLE LINER
Abstract
A collecting apparatus for drainage from the body of a patient
after severe wounding of or surgery performed on the patient,
embodying a canister and a disposable receiver for the drainage,
such apparatus having means for connecting the same in a vacuum or
suction system to stimulate drainage of the wound in the
patient.
Inventors: |
Pannier, Jr.; Karl A. (Salt
Lake City, UT), Reynolds; Gordon S. (Salt Lake City, UT),
Sorenson; James L. (Salt Lake City, UT) |
Assignee: |
Le Voy's Inc. (Salt Lake City,
UT)
|
Family
ID: |
25114895 |
Appl.
No.: |
04/778,963 |
Filed: |
November 26, 1968 |
Current U.S.
Class: |
604/320 |
Current CPC
Class: |
A61M
1/78 (20210501); A61M 1/604 (20210501) |
Current International
Class: |
A61M
1/00 (20060101); A61f 005/44 () |
Field of
Search: |
;128/275-278,283 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rosenbaum; Charles F.
Claims
We claim as our invention:
1. Drainage collecting apparatus for receiving exudates from the
body of a patient, including
a canister,
a removable cover for the canister,
a disposable liner receiver for removable insertion in said
canister,
tubular means for connecting the interior of the liner through said
cover to a tube leading from the body of a patient, and
means for placing the interior of both the canister outside the
liner and the liner in communication with a suction system.
2. The collecting apparatus of claim 1, wherein the canister is
rigid and the liner is of thinner material, flexible and
collapsible, and is maintained expanded when the vacua in the liner
and canister are countervailed.
3. The collecting apparatus of claim 1, including a safety valve
inside said liner to automatically limit the extent to which said
liner can be filled with body exudates.
4. The collecting apparatus of claim 3, wherein said tubular means
and the last said means are mounted in said cover and disposable
therewith.
5. The collecting apparatus of claim 1, wherein the cover and liner
are secured together and disposable as a unit. said opening
6. The collecting apparatus of claim 1, wherein said canister has
an opening in the bottom thereof, a seal on the bottom of said
liner sized for compressive insertion in said opening, and drain
tube means extending through said seal and the bottom of said
liner, whereby when said liner is placed in said canister with said
drain tube means extending through said opening a pull thereon will
draw seal into opening in an airtight engagement.
7. The collecting apparatus of claim 6, wherein said tubular means
includes a tubular portion extending to a point above but near the
bottom of said liner, and said drain tube means extends into said
liner to a point above the lower end of said tubular portion,
whereby an effective water seal may be established in said
liner.
8. The apparatus of claim 1, in which said receiver has a bottom, a
sealing element secured to said bottom to establish a friction seal
with an opening in the container, and drain tube means extending
through said sealing element and said bottom.
9. The apparatus of claim 26, wherein said tubular means and said
drain tube means extend within said receiver overlapping distances
adjacent said bottom, whereby an effective water seal may be
established within said receiver.
10. A disposable unit for association with a canister to receive
body exudates, including
a cover for the canister,
a liner receiver depending from said cover and having a closed
bottom for insertion in the canister,
tubular means carried by said cover for connecting the interior of
the liner to a tube leading from the body of a patient, and
other tubular means carried by said cover for placing the interior
of the canister outside said liner and the interior of said liner
in communication with a suction system.
11. The disposable unit of claim 10, wherein said cover is of thin
rigid material and said liner is of thin flexible material.
12. The disposable unit of claim 10, including a safety valve in
said liner to automatically limit the extent to which said liner
can be filled with body exudates to prevent any overflow into
either of said tubular means.
13. The disposable unit of claim 12, wherein said safety valve acts
to close off communication between the interior of said liner and
the suction system when the liner is filled to a predetermined
extent.
14. The disposable unit of claim 10, including a tear-out section
near one liner end defined by a line of weakening, and a tear-tab
secured to said section exteriorly of said liner to remove the
section and provide a drainage port.
15. The disposable unit of claim 14, including a safety valve in
said liner to limit the extent to which said liner can be filled,
and wherein said tear-out section is disposed above the limit
controlled by said safety valve.
16. The disposable unit of claim 15, including a carrying bail
secured externally to the bottom of said liner to support the same
during drainage through said port.
17. A receiver for body fluids, comprising:
a flexible body closed at the top and bottom thereof and adapted to
be received in a container;
tubular inlet means extending through the top of said receiver for
connection with a source of body fluid;
connecting means in the top of said receiver to establish
communication between the interior of said receiver and the
interior of a container outside of the receiver and a source of
suction whereby to effect countervailing of vacua; and
said receiver being of such economical construction as to warrant
its disposal after a single usage.
18. A receiver according to claim 28, in which said connecting
means comprise a tubular element projecting externally of said top
and having divergent passages one of which opens through the top to
the interior of said body and the other of which opens outwardly of
said body.
19. A vacuum bottle assembly for use in draining fluids from a
patient by suction apparatus, comprising
a generally rigid container having a hollow interior;
a drainage bag in the container interior; and support means
extending across the top of the container interior connected to
said bag for supporting the bag in suspended position in the
interior of the container, said support including conduit means
extending between the bag and the container exterior to an area to
be drained and between the bag and the exterior of the container to
a source of reduced pressure and further including means
communicating the container interior with a source of reduced
pressure.
20. The assembly of claim 19 wherein the drainage bag is made of a
generally flexible, collapsible material.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention or discovery pertains to the art of surgery, and
more particularly to a new type of receptor for receiving drainage
from a patient suffering from a severe wound, excess of fluid,
etc., the receptor having means for connecting the same in a vacuum
system, and embodying a canister in which is a disposable liner to
receive the drainage and after the liner is filled to a desired
level, it is removed from the canister and discarded, a new liner
being substituted.
2. Description of the Prior Art
It is well known that where a patient has received a wound,
accidentally or by surgical incision, which has entered a lung,
passed through the peritoneum, had a breast removed, for example,
drainage of blood, pus, excess liquid, and various exudates from
the wound or its vicinity is indicated to enhance the patient's
recovery rate and shorten convalescence. The most effective and
desirable way of accomplishing this drainage is to connect a
receptor in a vacuum line and remove the drainage from the
patient's body by suction. Heretofore, the only receptor for the
drainage has been a plastic or glass bottle or container equipped
with fittings for connecting the same to a tube leading from the
patient's body, to a suction or vacuum system, to permit draining
some of the contents of the container if desired, and other
purposes, which receptor must be removed, cleansed, and reused. The
cleansing of such a receptor is a most laborious and messy
operation, and the changing and cleansing of the receptor places an
extreme burden upon the nurses, other hospital workers, and the
sterilization facilities in the hospital. Spreading of infection is
a constant hazard in such an operation. The time, labor and care
necessary in such an operation is so great that the cost per
suction receptor rises to a tremendous amount, and some patients
require the use of as many as 10 to 15 receptors during a single
hospital stay. Thus, it is at once apparent that the procedure
heretofore found essential in connection with drainage receptors
was highly objectionable both to hospital and to the patient.
SUMMARY OF THE INVENTION
The instant invention provides drainage collecting apparatus in the
form of a receptor embodying a canister and a removable drainage
receiving liner for the canister. The drainage receiving liner is
very economical in construction, simple to remove and replace,
which operation can be accomplished by anyone and which should
require but a very few minutes, there being no real labor involved.
The canister need not even be washed and there is nothing to
sterilize, the drainage being fully contained within the liner and
discarded therewith. The attendant does not contact any surface
that was contacted by the drainage. Scales on the face of the
canister indicate the time when a liner must be changed for a new
one, there being a plurality of scales so that the same canister
may accommodate a plurality of sizes of liners, it only being
necessary to read the proper scale for a certain size of liner.
Means are provided for very simply sealing the liner airtightly
within the canister, connecting the liner to a tube leading from
the patient's body, connecting the interior of the canister to a
vacuum system, and a drainage tube is also provided for the liner.
In one form of the invention, within the liner a tube for drainage
overlaps in length with the tube leading from the patient's body so
that an effective water seal is easily established. The entire
structure is economical and the canister, of course is repeatedly
used. It can be seen therefore that the instant invention has
solved the problems and objections of the prior apparatus and
procedure, as mentioned above, in a most efficient, economical, and
effective manner. Labor on the part of hospital attendants and use
of the sterilization equipment is avoided and the hazard of
infection eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a canister and liner assembled
ready for use;
FIG. 2 is a reduced diagrammatic view illustrating the drainage
collection apparatus of FIG. 1 in operative association with a
patient and a vacuum system;
FIG. 3 is an enlarged vertical sectional view through the structure
of FIG. 1, with a part shown in elevation;
FIG. 4 is a part-sectional part-elevational view illustrating the
removal of a filled liner from the canister;
FIG. 5 is a perspective view of a canister and liner of a somewhat
different form, but also embodying principles of this
invention;
FIG. 6 is an enlarged vertical sectional view through the structure
of FIG. 5; and
FIG. 7 is a fragmentary vertical sectional view of the valve and
housing in the upper right-hand portion of FIG. 6, but showing the
same enclosed position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As stated above, the instant drainage collecting apparatus embodies
two major parts, a canister and a removable liner or drainage
receiver, generally indicated by numerals 1 and 2 respectively.
In the first embodiment of this invention, seen in FIGS. 1 through
4, the canister proper comprises the tubular body 3 fixedly
connected to a bottom 4, both parts preferably being of transparent
rigid plastic material. The bottom 4 is provided with a central
aperture 5, the surrounding edge of which is chamfered on both
sides as indicated at 6 to insure an effective airtight seal with
the bottom portion of the liner receiver 2, as seen best in FIG. 3.
One side of the body 3 is provided with a plurality of scales to
denote the amount of drainage within the liner receiver 2, FIG. 1,
there being two such scales shown in the drawing namely a smaller
scale 7 for a small liner and a larger scale 8 for a large liner.
Two liners, one for a child and for an adult will usually be all
that is necessary, the instant illustrations depicting a smaller
liner so scale 7 would be utilized whereas if a larger liner that
would expand to the inside wall of the canister were used, scale 8
would be read.
As seen best in FIG. 3, a cover 9 is provided for the canister,
which cover is of thicker, yet rigid plastic material, preferably,
and which cover need not be transparent. This cover can merely be
pressed into the upper end of the canister and an airtight seal
therebetween is established by an O-ring 10 or in an equivalent
manner. Permanently and airtightly secured to the cover through a
suitable aperture therein is an angular tube 11, preferably of
rigid transparent plastic material, which may be connected to a
vacuum or suction system.
The liner or receiver 2 is preferably formed entirely of
thermoplastic material, with the single exception of the filter
medium in a small air filter, and various parts thereof are
preferably connected together by fusing or electronic heat sealing,
although suitable adhesive materials could also be utilized. While
the making of this liner 2 of plastic material is not essential, it
is more economical, more efficient, light in weight, and easier to
assemble than with most other materials. Also, it would not be
injured if dropped on the floor as would be a material such as
glass.
This liner 2 comprises a tubular body 12, a top 13, and a bottom 14
fully enclosed except for essential openings through the top and
bottom. With reference more particularly to FIG. 3, it will be seen
that a short plastic tube 15 extends through a suitable aperture in
the cover 13 and is airtightly secured to the cover 13. This short
tube contains a plastic casing 16 open at the bottom and top, and
containing a filter medium 17 such as cotton or the equivalent.
Communication between the interior of the liner 2 and the interior
of the canister 1 is established by way of the tube 15 and the air
filter therein. No other communication between the canister 1 and
liner 2 is possible during operation of the apparatus. A second and
preferably rigid tube 18 extends from a point near the bottom of
the liner 2 just through the cover thereof, where the end of the
tube is telescopically received within a flexible plastic tube 19
and securely attached to the tube 19 and the top cover 13 of the
liner. A removable elbow tube 20 of rigid plastic has an inner
tapered end 21 which passes through a suitable aperture in the
canister cover 9 and may be telescopically and airtightly engaged
with the aforesaid flexible tube 19 as seen at 22 in FIG. 3. The
tube 20 is expendable, may readily be removed from the liner and
discarded therewith after usage.
A cup-shaped seal 23 is attached to the bottom of the liner
centrally thereof, and this seal is made of thicker plastic than
the liner, and a plastic providing a relatively soft outer surface
that is not as smooth as the surfaces of the plastic tubes. This
sealing cup when engaged within the chamfered edge 6 at the bottom
of the canister as seen in FIG. 3 establishes an airtight seal
between the liner and canister bottom. Drain means for the liner
are provided in the way of a flexible tube 24 in end to end
relationship with a rigid tube 25, both tubes being secured
together and to the sealing cup and bottom of the liner by way of a
suitable sleeve 26 extending through both the sealing cup and liner
bottom. The tube 25 extends upwardly inside the liner a
predetermined distance from the bottom thereof but above the lower
end of the aforesaid tube 18. The overlapping end portions of the
tubes 18 and 25 provides the requirements necessary for an
effective water seal as indicated by the level in FIG. 3, and the
rigidity of the tubes 18 and 25 prevent accidental maladjustment
that would adversely affect the water seal. The water level is just
below the upper end of the tube 25 and corresponds with the lower
unnumbered line 27 beneath the canister scales 7 and 8, FIG. 1.
Water seals of the type shown in FIG. 3 are customarily utilized in
apparatus for the main purpose of preventing any inadvertent flow
of air to the body of the patient so no bacteria could be carried
back to the patient should this accident occur. Normally, during
usage, a clamp 28 is secured to the flexible tube 24 to prevent
drainage therethrough. This clamp may be released when drainage is
desired for any reason.
At the outset a hospital or the like may purchase a canister and
lid assembly therefor, which is retained for continued and repeated
usage, and a supply of liners with an inlet tube 20 packaged with
each liner in a sterile condition. Thereafter, only liners need be
purchased for use with that single canister, and, if desired, the
hospital may purchase a supply of canisters and keep a stock of
liners of different sizes on hand which may be used with any of the
canisters.
In use, the instant invention is extremely economical, labor saving
and efficient. The apparatus may be simply and easily assembled for
usage. While the steps mentioned herein need not be followed in
precisely the same order, perhaps the simplest procedure for
assembling the apparatus is to take the liner and inlet tube 20
therefor out of its wrapper, insert the inlet tube in the cover of
the canister and then telescopically and airtightly attach the
flexible tube 19 from the liner to the inlet tube on the underside
of the cover. The liner may then be carried by the cover and
disposed within the canister with the drain tube 24 of the liner
passing through the opening 5 in the bottom of the canister and the
clamp 28 may be placed on the drain tube outside the canister. The
lid is replaced on the canister in an airtight position, and a pull
on the drain tube from below the canister will effectively
establish an airtight connection between the sealing cup 23 and the
chamfered edge 6 defining the opening 5, the diameter of the
sealing cup 23 being very slightly greater than the diameter of the
opening 5. The apparatus may then be mounted on a stand 29, as
illustrated in FIG. 2, or on any other suitable apparatus, and
water put into the liner through the tube 20 and tube 18 until the
proper level of water seal is established. The tube 20 may then be
connected to a tube or catheter 30 leading from the body of a
patient 31, and the tube 11 carried by the canister cover 9 is
connected with a tube 32 plugged into a vacuum or suction system
connection 33 in the wall of the hospital room.
Suction may then be started, and air will first be withdrawn from
the canister, by virtue of the resistance provided by the air
filter in the tube 15 connected to the liner, and the liner will
then expand due to the pressure differential and air will be drawn
from the interior of the liner until the vacua of the flexible
liner and the canister are countervailed, whereupon the liner will
remain expanded.
Exudates will then be drawn from the patient's body into the liner.
When the liner has collected a sufficient amount of fluid, the
scale 7 on the canister being utilized for the liner illustrated
owing to its small size as stated above, and then the suction may
be temporarily stopped, the liner removed and replaced with a new
liner.
This operation is extremely simple. It is simply necessary to put a
clamp on the tube 30 from the patient's body, and either before or
after removing the cover 9 from the canister pull the tube 20
through the canister cover thus disconnecting this tube from the
flexible tube 19 on the liner. It is not necessary to disconnect
the tube 11 from this suction line. The tube 20 may be then
disconnected from the tube 30 and discarded completely. The
operator may then pinch the tube 19 on the liner between his thumb
and finger or clamp the tube as indicated at 34 in FIG. 4. This
tube may then be used to lift the liner out of the canister, a
simple push of a finger on the sealing cup 23 being sufficient to
disconnect the liner from the canister at that point. The liner is
then removed and discarded either before or after being drained,
according to the desire of the operator and a new liner and tube 20
being assembled with the canister in the manner above
described.
Alternatively, the liner may be removed from the canister by means
of an upstanding plastic loop 35 secured to the top 13 of the liner
in the event the operator does not wish to touch the tube 19 for
any reason. This loop 35 also serves as a hanger for the liner in
the event it is used without the canister.
There is no washing of the canister for reusage since it has not
become contaminated and the discarded liner is of little bulk and
is easily disposed of without contamination of the operator, the
patient, or the environment and the whole operation requires an
exceedingly small amount of labor.
The instant invention may have other uses and purposes as will be
apparent to one skilled in the art. For example, it has long been
considered desirable, if possible, where a patient loses a lot of
healthy blood during an operation to collect as much of that blood
as possible and use it for a transfusion into the same patient,
since one person's own blood is more acceptable to that person than
the blood of another person, even though they are both of the same
type. The instant apparatus could well be utilized as a collector
for that healthy blood, and the transfusion thereof back into the
patient could be made through the drain tube in the bottom of the
liner. It is understood of course that the blood would be provided
with the necessary additives and filtered on the way from the
patient to the canister and liner therein although the necessary
additives might well be added to the blood while in the canister or
liner through the tube 20.
For certain usages and hospital installations, a water-seal and
drain at the bottom of the liner receiver may not be needed, and
accordingly the liner may be constructed with a closed bottom, the
long tube 18, and the tubing 24 and 25 along with the seal 23 being
omitted. Also in many cases it is desirable to have an arrangement
eliminating any possibility of contamination during connecting or
disconnecting of the suction and body tubing and in removing and
replacing the canister cover.
To this end, we have illustrated in FIGS. 5, 6 and 7 a modified
form of the instant invention that is safer to the operator against
contamination even when carelessly handled and which eliminates
some of the plumbing between the lid and bag as previously
described herein.
In this instance, canister 36 is utilized, this canister having a
fully closed bottom 37 and in other respects is like the canister 1
previously described. A canister cover 38, which differs distinctly
from the cover 9 above described, is provided with a downwardly
turned flange 38a to intimately fit over the upper margin of the
wall at the opened end of the canister. This cover is preferably
molded of plastic material as shown, and the fittings associated
with that cover are either molded along with the cover or fused
thereto; although the cover might be made of thin metal and the
essential fittings adhesively or equivocally secured thereto. These
fittings including a tube 39 extending through the cover in an
intermediate location, which tube is for connection to the tube or
catheter 30 leading from the body of the patient 31, as seen in
FIG. 2. Another externally projecting tubular fitting 40 having a
base portion 41 of enlarged size is also secured to the cover in a
position such that the base portion 41 will be immediately adjacent
the canister wall just to the inside thereof, as seen in FIG. 6.
This base 41 is provided with a pair of downwardly divergent
passages therethrough, namely an outer passage 42 and an inner
passage 43, both of which open through the cover 38. The tube 40 is
for connection to the vacuum line 32.
For disposition within the canister 36 is a thin flexible plastic
receiver 44 of the same material as the hereinabove described
receiver 2. The receiver 44, however, is provided with an entirely
closed bottom 45 while the top end of the receiver is initially
entirely open. The margin around the opened end of the liner or
receiver 44 is folded over as indicated at 46 in FIG. 6 and is
firmly secured to the underside of the cover 38 entirely
therearound with the top end of the liner approximately fully
expanded. Directly beneath the base 41 and the tubular fitting 40
the upper margin of the liner 44 is inwardly deviated as indicated
at 47 in FIG. 6 so that the liner is secured to the cover beneath
the solid portion of the base 41 between the divergent passages 42
and 43.
This leaves the outer and larger passage 42 communicating with the
interior of the canister but outside the wall of the liner, while
the inner and smaller passage 43 communicates with the interior of
the liner. Thus, when the tube 40 is connected to the suction line,
the initial suction will be stronger outside the liner than inside
until the vacua of the flexible liner and the canister are
countervailed, whereupon the liner will remain in expanded
condition. Filtering means may be incorporated in the passages 42
and 43 if so desired, as indicated in FIG. 6.
In order to protect the hospital vacuum system, which systems are
usually built-in, a safety valve assembly is provided within the
liner 44. This assembly includes a housing 48 having an opened
upper end secured by fusion, adhesive, or any other desired manner
to the underface of the cover 38 from which the housing depends in
position to be in open communication with the inside passage 43 of
the tube assembly 40. A valve seat 49 having a central aperture 50
therein extends across the upper portion of the casing and below
that valve seat the casing is provided with a series of apertures
51 therearound. The bottom of the casing 48 is closed around a tube
52 which projects into the casing to a point below the valve seat
49. The end of the tube within the housing is covered by a
relatively light diaphragm 53, of rubber or equivalent material,
and preferably having the shape of a blunt cone. This diaphragm 53
is the safety valve itself. As seen in FIG. 6 the tube 52 extends
well below the inner end of the tube 39 which connects with the
patient's body. During operation, the valve will be in the position
seen in FIG. 6 and suction is effective to the interior of the
liner 44 through the hole 50 in the valve seat and the apertures 51
in the wall of the housing 48. However, through the neglect,
carelessness or for any other reason should the liner 44 become
filled with drainage to the point it might overflow and the
drainage enter the hospital suction system, the valve will assume
the position seen in FIG. 7 and close the port 50 in the valve seat
so that suction to the interior of the liner is no longer
effective. This is caused by liquid rising within the tube 52,
compressing the air therein since the vacuum is not perfect but
only to a desired degree and when that air pressure reaches a
certain point it will cause the valve to reverse from the position
of FIG. 6 and assume the position of FIG. 7. No drainage will enter
the line leading to the patient's body through the tube 19 since
before the collected drainage reaches that point the valve will
have operated.
Preferably above the point to where it is possible to fill the
liner 44 with drainage, the liner is provided with a tear-out
section 54 defined by a line of weakening 55, this line being
pointed at the starting end as indicated at 56 to facilitate easy
removal of the section 54. To effect the removal of this section, a
tear-strip 57 is provided on the outside of the liner and sealed to
the section 54 at the weakened line 55. In some cases it is
desirable to empty the liner 44 before disposing of the same and
this is especially desirable when the accumulated drainage is of a
heavy viscous character.
It is apparent that the cover 38, the liner 44, the safety valve
assembly, and the fittings 39 and 40 are all assembled as an
integral unit, the entire unit being disposed of and replaced by a
new unit after the liner is filled with drainage. To facilitate
handling the unit, diametrically opposed brackets 57--57 or any
other desirable connecting means may be provided, preferably on the
skirt 38a of the cover, to which a bail 58 is pivotally connected.
Also, the liner is provided with a bail 59 on the bottom thereof,
which bail may be in the form of a plastic strap fused to the
bottom of the liner.
In use, this embodiment of the invention is highly effective, time
saving, and entirely safe from the standpoint of contamination of
either the apparatus associated with the liner or the operator
handling the same. The liner and canister are assembled in the
manner seen in FIGS. 5 and 6, and the tube 39 connected to the tube
leading from the patient's body, and the tube 40 connected to the
suction system. Operation is then in effect in a minimum amount of
time and labor. When the liner becomes filled to the extent
possible with drainage or no further drainage is necessary, it is a
simple expedient to disconnect the lines from the tubes 39 and 40
and with the aid of the bail 58 lift the cover 38 and liner off and
out of the canister and either dispose of the same or empty the
liner of drainage before disposal. The liner may be emptied easily
and safely by suspending the cover and liner unit over the drainage
sink with the aid of the bail 58, tear out the section 54 of the
liner then grasp the liner by the bottom bail 59, and invert the
unit over the sink until it empties. It will be noted that during
this operation none of the contents of the liner will be in contact
with the hands of the operator. Likewise there can be no
contamination of the lines leading to the suction system or to the
patient's body by virtue of overflow, since such is effectively and
automatically prevented by the safety valve 53. After removal of
the cover-liner unit from the canister, a new unit may be easily
inserted and connected in the manner above described. No
sterilization of the canister or lines leading thereto is
necessary, since nothing can become contaminated.
It will be understood that modifications and variations may be
effected without departing from the spirit and scope of the novel
concepts of the present invention.
* * * * *