Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BAC~GROUND OF THE INVENTION
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Flexible plastic parenteral solution containers
are presently sold by Travenol Laboratories, Inc. under
the trademark VIAFLEX ~. These containers have many
substantial advantages over glass bottles of parenteral
solution, particularly in their reduced weight, lack of
susceptibility to breakage, and freedom from the need to
allow air to bubble into the solution container as it
drains.
The presently available plastic parenteral
solution bags are made of a pair of flat sheets of poly-
vinyl chloride plastic, heat-sealed at their edges to
form a sealed, sterile container. In the past, various
attempts have been made to replace the heat-sealed
plastic solution containers with blow molded containers.
However, one drawback to the use of such blow molded
containers i5 the fact that, when hung from one end with
solution being drawn out of them from the other end, they
tend to collapse in an incomplete manner. This is parti-
cularly so when hydrocarbon polymers, e.g., polyolefins
such as polypropylene, are used.
The reason for this incomplete collapse is that
the stiffness of a thin-walled polypropylene container
frequently tends to resist collapse to such a degree
that the moderate suction pressure exerted on the con-
tàiner by weight of the fluid in an administration set
attached to the container is insufficient to cause its
complete collapse.
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Another disadvantage of the prior art solution
containers made from blow-molded parisons is that they
tend to collapse in a non-uniform manner. On some oc-
casions these devices, which are generally oval in shape,
collapse along the long axis of their oval cross-section,
but on other occasions they tend to collapse along both
the short axis of the cross-section as well as the long
axis. As a result of this, it becomes quite difficult
for a nurse to determine exactly how much solution has
passed out of the solution container.
In accordance with this invention, a collapsible
parenteral solution container is provided which can ad-
vantageously be made of stiffer, more desirable plastic
material such as polypropylene, while still being readily
collapsible in normal therapeutic use as a dispenser of
parenteral solution. Also, the novel container of this
invention collapses in a uniform manner, which simplifies
the determination of the amount of fluid remaining in the
container at any time. Likewise, the container collapses
more completely under normal suction exerted by the suction
head of solution in the administration set.
Also, the container of this invention can be more
economically produced by the novel mold of this invention
in a blow-molding process than the flat, heat-sealed
sheet type solution containers of the prior art.
DESCRIPTION OF THE INVENTION
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In accordance with this invention, a molded,
collapsible solution container is made from a tubular
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plastic parison, The container defilles a body portion having
an integral neck portion and shoulder portion at one end
thereof, and is sealed the opposite end. The body porlion de- -
fines, in as-molded configuration, a generally oval, trans-
verse cross-section adjacent the neck and shoulder portion,
which cross-section tapers progressively to a flat configuration
at the end of the container opposite to said one end as defined
above. This facilitates a uniforn~ manner of nat collapse of
the container progressively from its opposite end toward the
one end as defined above, as the contents of the container are
withdrawn through the neck portion, when said container is
disposed in neck-downward position.
It is particularly preferred that, in the collapsible
solution containers of this invention, the circumferences of the
transverse cross-sections defined by a major portion of the
length of the container are essentially constant, which facili-
tates the nat collapse of the container of this invention.
l~urthermore, the solution container of this in-
vention preferably defines a pair of longitudinal lines of flexing
weakness defined in diametrically opposite relation to each
other at the extremes of the long axis of the oval cross-sections
defined above, for further facilitating of the flat collapse. Also,
the plane of the flat, opposite end of this container is generally
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parallel to the long axis of the oval cross-sections of the
container .
Also, gusset portions are defined in the body
portion adjacent the shoulder portion. The ~usset portiolls
include lines of flexing weakness to facilitate the collapse
of the container adjacent the shoulder portion as the con-
tents thereof are withdrawn, typically through the neck
portion while the container is disposed in neck-downward
position. ~n these circumstances, the gussets can facilitate
both the lateral and longitudinal collapse of the container
as it is emptied.
Furthermore, transverse lires of folding
weakness are deMned along opposite edges of the shoulder
portion to facilitate the collapse of the container in a manner
described below,
The collapsible solution container of this
invention is preferably made of a polyolefin plastic
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such as polypropylene, since these materials can be
formulated to have an extremely low content of substances
which can leach into solutions carried by the container.
Also, the polyolefins are quite inexpensive, and possess
many other desira~le characteristics such as strength,
high softening temperature (to permit autoclaving of the
flexible containers), and the like.
In the drawings, one preferred specific
embodiment of the solution container of this invention
is shown.
Figure 1 is a perspective view of a collapsible
solution container of this invention in use for adminis-
tering parenteral solution to a patient.
Figure 2 is an inverted, elevational view of
the solution container of this invention in as-molded
confi~uration, resting in the mold used to manufacture
the container, with portions of the mold broken away to
show the solution container inside.
Figure 3 is a plan view of the solution container
of this invention, showing the neck and shoulder portions
thereof.
Figure 4 is an elevational view of the solution
container of Figure 2, inverted in its typical position of
use.
Figure 5 is an elevational view similar to
Figure 4, after approximately one-half of the liquid
contents ha-~e been removed from the solution container.
Figure 6 is a perspective view after essentially
all of the liquid contents have been removed from the
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container of this invention, showing how the hottom of
the container collapses under the influence of a normal
suction o~ a column of parenteral solution in an attached
administration set.
Figure 6A is a fragmentary elevational view of
the shoulder portion of the container of Figure 6.
Figure 7 is a sectional view taken along
Line 7--7 of Figure 2.
Figure 8 is an enlarged, fragmentary, eleva-
tional view, taken in longitudinal section, of part of
the container of Figure 2 when under the condition of
Figure 5.
Figure 9 is an enlarged, fragmentary, eleva-
tional view, taken in longitudinal section, of part of
the container of Figure 2 when under the condition of
Figure 6.
Figure 10 is a schematic, elevational view
showing how the mold of this invention is used in a blow
molding operation to manufacture the container of Figure
2.
Referring to the drawings, a molded, collapsible
solution container 10 is disclosed which defines a body
portion 12 having an integral neck portion 14 and shoulder
portion 16 of one end thereof. Neck and shoulder portions
14, 16 are preferably relatively stiff, while the rest of
the container is flexible and collapsible. Container 10 is
sealed at its end 18 opposite the neck and shoulder portions 14,
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16, and includes a flattened portion 20 having a hanger
hole 22 so that the container may be hung up in the manner
illustrated in Figure 1 for convenient administration of
parenteral solution or any other m~terial as desired.
Figure 1 schematically shows such an
administration operation, in which an administration
set 23, conventionally including a drip chamber 24 and
flexible tubing 26, connects the interior of container
10 with an infusion needle 28 in the arm of a patient,
for flow of parenteral solution from container 10 to an
arm vein in a manner controlled by flow clamp 30.
Neck portion 14 of container 10 is proportioned
to receive a cap portion 32, which may be attached to
the neck portion by heat welding or the like. Cap
portion 32 is generally made of semi-rigid plastic, and
is shown to contain a pair of tubular access ports 34
which, prior to opening, are occluded by diaphragms 35
across the bores of the tubular ports. Accordingly,
container 10 is opened by inserting a sterile, hollow
spike of an administration set into one of the access
ports 34 to rupture the diaphragm. The spike is selected
to be proportioned for sealing, sliding contact with the
interior of port 34, so that solution passes only through
the hollow spike and into the administration set 23.
The other of the two access ports 34 may carry
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a latex injection site for the administration of supple-
mental medication or the like to the contents of container
10 .
As shown in Figure 2, container 10 is typically
molded without cap 32, the cap being added later.
Figure 10 schematically shows a blow molding
apparatus which is used to manufacture the collapsible
container of this invention. Blow molding in general is
a well developed arm of technology, and many different
techniq~es of blow molding are currently available to
those skilled in the art, and useable for manufacturing
the containers of this invention. In particular, the
well-known Orbet*process, which is available under license
from the Phillips Petroleum Company of Bartles~ille,
Oklahoma, is a highly suitable manufacturing process for
the container of this invention.
A tubular parison 36 of hot, molten plastic
is extruded in a conventional manner and lowered into
mold halves 38, 40, and neck mold portions 48, 50, which
are then brought together by pistons 42, 44, 45, 47. A
blowing tube 46 is introduced into the mold at an appropri-
ate time during the process, and air is introduced to expand
the hot parison outwardly until it is stretched to match
the configuration of the interior of closed mold halves
38, 40. The formed container within mold halves 38, 40
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is allowed to cool. Thereafter, blow tube 46 may be
withdrawn; the molds opened; and the container ejected.
Flattened portion 20 is formed by an end of
mold halves 38, 40 as shown in Figure 10. :
Accordingly, the flexible container of this
invention, in as-molded configuration, assumes the novel
shape of the mold cavity shown herein in Figures 2 and
lO, with that shape being more fully disclosed in Figures
3, 4, 7 and 8.
After cooling, the respective mold halves are
opened, and container 10, exhibiting the as-mol~e~ -
configuration shown in the previously m~ntioned figures,
j is removed.
In accordance with this invention, the solution
container, in its original unstressed state, (i.e in its
as-molded configuration), defines a generally oval, transverse
cross-section adiacent the neck and shoulder portions 14, 16
as generally shown in Figure 3. As shown in Figure 4, this
, cross-section tapers progressively in container section 49 to
1 20 generally flat configuration at the end 18 of the container
which is opposite from the end having neck and shoulder portions
14, 16. In this specific embodiment, the tapered section 49
~egins at point 51, being spaced from shoulder portion 16
by an optional length of parallel walled container section
53, which preferably extends less than half of the
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container length, so that section 49 constitutes a major
portion of the container.
The purpose of tapered section 49 is to facili-
tate a uniform manner of flat collapse of the container
progressively frorn end 18 towards the neck and shoulder
end of the container, as the contents thereof are with-
drawn through neck portion 14, when the container is
disposed in necX-downward position. This effect is
progressively illustrated in Figures 4, 5 and 6.
The container of this invention thus collapses
reliably in a uniform manner, which permits the nurse to
accurately judge how much parenteral solution has been
expended from the collapsible container by no more than
a quick glance, rather than having to manipulate the bag
or carefully examine it, as is the case in the prior art
flexible containers.
The shape of the bag of Figure 4 is idealized,
in that the specific shape shown shows the bag in as-
molded condition for purposes of illustration. Actually,
the pressure of the liquid in the container would cause
the inverted container of Figure 4 to be a little fatter
at ~he bottom, and thinner at the top, than is shown in
that figure.
It can be seen from Figure 2 that the lateral
2~ edges 58 of container 10 are not parallel, but diverge
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slightly over most of their length in the direction
running from the end of the container carrying neck 14,
to end 18. This is an aspect of the shape of the container
10 which causes, along a major portion of the length of
the container, the circumferences of all axially perpendi-
cular, transverse cross-sections to be essentially constant.
Accordingly, as container 10 gets thinner in
its transverse dimension (illustrated in Figure 4) as
one moves toward end 18, it correspondingly becomes wider
in its lateral dimension as shown in Figure 2 as one moves
toward the same end 18. As a result, the peripheral
length or circumferences of most transverse cross-
sections, perpendicular to the container's longitudinal
axis, will be essentially constant. For example, transverse
sections 56 and 57 will be essentially uniform in peri-
pheral length or circumference.
The wall thickness of the polypropylene containers
of this invention preferably varies from about 0.02 to 0.01
inch. It is generally preferable for the wall thickness
at end 18 to be about 0.01 inch, with the wall thicXness
increasing gradually to a maximum of about 0.02 inch in
the area of shoulder portion 16.
Furthermore, a pair of longitudinal lines of
flexing weakness 58 are defined along both lateral
container edges, to further facilitate the flat collapse
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of container 10. A cross-sectional detailed view of
line of flexing weakness 58 is illustrated in Figure 7,
along with the corresponding structure of mold halves 38,
40. As expanding tubular parison 36 comes into contact
with the walls of mold halves 38, 40, it tends to quickly
cool and harden. The expanding parison first encounters
mold halves 38, 40 at areas 60, 62, and in those areas
the parison hardens quickly and becomes immobile.
However, the mold halves define cutaway portions 63, 64
in which the parison can still expand, and in so doing,
it reduces its wall thickness as indicated. Eventually,
the parison fills the cut-away area 63, 64, but here
its expansion has formed a linear portion of circular or
U-shaped cross-section having a minimum wall thickness
therein of 0.002 or 0.003 inch less than the surrounding
wall thickness. Accordingly, a line of flexing weakness
58 is formed in the circular or U-shaped cross-section.
The radius 65 of the circular or U-shaped cross-section
may be about 3/64 inch.
The plane of flat end 18 of container 10 is
preferably parallel to the long axis 66 of the oval
shoulder area 16 as shown in Figure 3. This also
fasilitates uniform, flat collapse.
Generally triangular gusset portions 68 are
provided adjacent shoulder portion 16, and in recessed
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relation thereto, so that shoulder tips 70 protrude out-
wardly from the gusset pGrtions. Each gusset portion 68
is bounded by three side portions 72, 74, 76, each of
which define lines of flexing weakness which may have a
structure similar to lines of flexing weakness 58.
However, line 72 defines an angle pointing inwardly toward
the interior of the bag, while lines 74 and 76 may be
lines of weakness having an outwardly pointing, circular
or U-shaped cross-sectional structure similar to that
shown in Figure 7. Lines of weakness 72, 74, 76 may be
formed by appropriate grooves in the mold halves (for
forming lines 74, 76) and appropriate ridges in the mold
half for forming line of flexing weakness. ~11 of the
lines of flexing weakness 58, 72, 74 and 76 may simply
constitute crease lines molded into the bag wall by
appropriate grooves or ridges in the mold. Any suitable
crease line which permits angular variation between
sections of the bag walls may be utilized in this inven-
tion.
The gusset structure permits the further collapse
under normal suction pressure of the type exerted within
the container due tO the weight of the solution in
administration set 26 and the normal elevation of the
container as used. The container collapses b?th longitu-
dinally and laterally in the region of gusset 68, adjacent
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shoulders 16, which further reduces the volume of the
collapsed container, and permits the expulsion of more
parenteral solution. This is particularly illustrated by
Figures 6A and 9, when compared with Figures 5 and 8.
The side edges of shoulder portion 16 each
define a transverse line of folding weakness 81 which
facilitates the collapse of the container of this
invention as particularly illustrated in Figures 6 and 6A.
Mold halves 38 and 40 desirably contain vent channels
83 wh~ch communicate with the respective grooves in its
mold half which form the various lines of flexing
weakness, particularly those grooves which are not on
the parting line of the mold as are cutaway areas 63,
64. Vents 83 permit air to escape from grooves formed
in the mold halves to define various lines of weakness,
so that the lines of weakness in the container wall can
expand more fully into the grooves which are so formed.
Transversely disposed, circumferential line
of weakness 78 is an optional, additional line of
flexing weakness which can be used to facilitate the
inward collapsing of the bag walls adjacent shoulder
portion 16, as illustrated in Figure 6. It may also
be molded in the manner of Figure 7, or any other
desired manner.
The flexible container of this invention can
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be easily molded, filled with parenteral solution or any
other desired product and sterilized if necessary by
autoclaving, particularly when the container of this
invention is made of a high melting plastic such as
polypropyIene. When the contents are drained from the
inverted container, the container collapses in a uni-
form manner to permit the accurate measurement of the
amount of the solution withdrawn from the container, even
though the container includes less residual air than
has been previoùsly required in order to conveniently
read the amount of liquid expended from the container.
The above has been offered for illustrative
purposes only, and is not intended to limit the inven-
tion of this application, which is as defined in the claims
below.
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