Note: Descriptions are shown in the official language in which they were submitted.
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SPOUT FOR FLEXIBLE FLUID RESERVOIRS
BACKGROUND
In the field of flexible fluid reservoirs, particularly those comprised of two
opposing
panels of film selectively bonded together and incorporating a closable spout
there
between, attention has been directed to providing a secure and durable bond
between
the opposing panels of film and the spout. To enhance the nature of bond
between the
films and the spout, various approaches have been taken, including inclusion
of surface
features such as ribs, lands and/or grooves in the spout. While intended to
address a
perceived problem, such solutions were not without deficiencies. Moreover,
little.
attention has been paid to the parameters surrounding the components, namely
the
spout and the film, with respect to the chemical properties thereof, and how
best to
optimize the same'.
Turning first to issues pertaining to the physical attributes of the spout,
spout rib
geometries of the. prior art generally produced excessive pressure at the weld
interface,
causing the material of-the film subject to bonding.with the spout to be
displaced rather
than bond with adjacent material on the spout rib. As this material was
displaced, the
remaining film at this location was considerably weakened, making it
particularly subject
to tearing.
In addition to the foregoing, prior art spouts often included a spout geometry
that
resulted in stress concentration at the spout corners (in most forms, the
spout corners
are considered those locations where the two generally opposing side surfaces
of the
spout's weld interface converge) when the reservoir was filled to near
capacity. This
intrinsic stress was greatly amplified when the reservoir was subjected to
additional
loads such as those experienced during "drop-testing". In addition,
conventional spout
geometries, particularly in conjunction with stiff material selection, created
high stress
and abrasion of the film where it wrapped around the internal edge of the
spout. This
could result in premature failure of the film in this area.
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As noted above, prior art spouts for flexible fluid reservoirs were not known
to
possess nor designed to possess melting temperatures that were matched to that
of
target films intended to be heat or radio frequency (RF) welded thereto. As a
consequence, when such a spout and target film were subjected to such welding,
desired bonding qualities were not always achieved. While one solution was to
apply
excess heat and/or pressure to accommodate these disparities, such a solution
jeopardized material performance features, particularly in the more
susceptible films. In
certain instances, the melt temperature of the spout base material, such as
high density
polyethylene (HDPE), was 8 C higher than the base material of the film's
bonding layer,
such as linear low density polyethylene (LLDPE), which resulted in a less than
desirable
final weld. As a consequence, flexible fluid reservoirs constructed from a
film material
that was welded to such a spout would experience preventable failures at this
interface.
SUMMARY OF THE INVENTION
The invention is intended to provide a spout, particularly for flexible fluid
reservoirs
comprising opposing film panels such as the type broadly characterized as
personal
hydration reservoirs, which minimizes stresses and abrasion resulting from
manufacture
and/or use of such reservoirs as well as enhances the strength of the
weld/bond
between the films and the spout. The various invention embodiments minimize
stresses
to and abrasion of the film(s) comprising such reservoirs by exploiting
certain spout
geometries, and enhances the strength of the weld/bond between the films and
the
spout through material selection and spout surface characteristics, the
details of which
will be disclosed in the following paragraphs.
Each spout according to the invention comprises a generally cylindrical neck
portion
and a pair of opposed, generally triangular portions, extending laterally
there from that
comprise a spout-film interface (also referred to herein as a "spout weld
interface"). The
neck portion includes an axis that is congruent with a longitudinal direction.
Depending
upon embodiments, the spout weld interface(s) may comprise one or more
portions of
the neck portion.
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For purposes of this patent, the terms "area", "boundary", "part", "portion",
"surface",
"zone", and their synonyms, equivalents and plural forms, as may be used
herein and
by way of example, are intended to provide descriptive references or landmarks
with
respect to the article and/or process being described. These and similar or
equivalent
terms are not intended, nor should be inferred, to delimit or define per se
elements of
the referenced article, unless specifically stated as such or facially clear
from the
several drawings and/or the context in which the term(s) is/are used.
Specifically as
used herein, reference to a "weld interface" also includes the plural form and
vice versa,
and should not be inferred as limiting the embodiments or claimed invention to
one form
or the other based solely upon term selection and usage.
Certain spout embodiments of the invention comprise at least one material
having a
melting temperature, at least at spout weld interfaces thereof, which is
closely matched
to at least a portion of film-spout interfaces that that are part of a
flexible fluid reservoir
film (also referred to herein as "film weld interface(s)"). By closely
matching the melt
temperatures of the contacting materials at the film/spout weld interfaces,
preferably at
least within 5 C and most preferably within 2 C, undesirable material
displacement at
the weld interfaces can be eliminated (presuming substantially homogeneous
material
temperatures). Research has shown that by reducing and preferably eliminating
material displacement during the welding process, weld and/or material
failures that
might otherwise occur at the weld interface, and/or at areas of the film
immediately
adjacent to such interfaces, are significantly reduced. Thus, the film weld
interfaces,
which is usually, but not always, an inner surface of the film at such
interface, comprises
a material, preferably a LLDPE, that has a melting temperature closely matched
to the
melting temperature of the material at the spout weld interface, which is
usually, but not
always, an outer surface of the spout, which is also preferably a LLDPE. In
such
preferred compositions comprising LLDPE at the film and spout weld interfaces,
a
convenient means for matching melting temperature requirements is thereby
provided.
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In certain embodiments of the invention, pre-welded or exposed spout and/or
film
weld interface material may not be the primary or ultimate bonding media, but
may be
removed or overcome during the bonding process (as in the case of a volatile
coating
that is flashed or becomes a flux during bonding operations). However, in
presently
preferred embodiments, the pre-bonded spout and/or film weld interfaces
comprise the
closely matched melting temperature materials that form a suitable bond during
a
bonding or welding process comprising the application of heat and/or radio
frequency
(RF) energy. Thus, weld material selection is not constrained to that of the
spout and/or
film outermost or exposed surface, but to the functional material (surface)
exposed
during bonding operations.
Spout embodiments of the invention also may provide for enhanced spout weld
interface surface and sectional characteristics as well as geometries. The
surface
characteristics comprise substantially flat and/or smooth surfaces, which
permit uniform
and/or lower material compression pressure to be used during welding, when
compared
to the prior art. By minimizing sectional thickness differences in adjacent
portions of the
spout weld interfaces, e.g., no substantial ridges, lands, protrusions or
similar positive
relief features reside on at least a substantial portion of the spout weld
interfaces,
displacement/extrusion of film weld interface material(s) is thus greatly
minimized. As a
consequence, film thickness and integrity at and proximate to the film weld
interface can
be maintained during and after the bonding process.
Certain embodiments of the immediately preceding type may also comprise
negative
relief surface features such as holes or depressions defined by the spout weld
interface
surfaces. As opposed to positive relief surface features, negative relief
surface features
such as depressions or holes beneficially permit air entrapped between film
and spout
weld interfaces during boding to escape or not adversely affect the desired
weld, thus
enhancing the film-to-spout bond. Additionally, such surface features also may
accept
displaced film/spout material, further enhancing the nature of the bond there
between.
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The skilled practitioner should appreciate that with respect to the foregoing,
spouts
having weld interfaces comprising lands and grooves are not equivalent to weld
interfaces comprising a generally smooth surface (no positive relief features)
but also
defining negative relief features, which may include linear negative reliefs.
In the former
instance, the peaks of the lands do not constitute a "surface" within the
meaning of this
patent; "surface" as used herein denotes the nominal surface of the material.
Moreover,
negative surface features of the various invention embodiments are generally
limited by
the sectional thickness of the spout weld interface; positive relief features
have no
equivalent limitation.
In addition to the foregoing, spout embodiments,of the invention also may
comprise
at least one stress delocalizing feature ("SDF"), which is particularly useful
when spouts
according to the invention are used with flexible fluid reservoirs having
opposing film
panels at the spout weld interface. As. noted previously, displacement of
reservoir
panels at the spout weld interfaces causes the localization of stress along
the free edge.
of the interfaces. This stress localization is often a precursor condition to
failure of the
weld/bond at the spout/panel weld interfaces. By incorporating at least one
SDF,
stresses otherwise directed to the interfaces are distributed over a wider
area (of both
the spout and the panels), thereby reducing the likelihood of failure at the
interfaces.
One form of SDF comprises flexible appendages, preferably at the convergence
of
opposing sides of a spout (the apex of the triangular portions) or at neck
portions that
form a portion of the spout weld interfaces, which depend beyond the spout
weld
interface and into the reservoir. These flexible appendages are functionally
hinged to
the spout weld interfaces such that upon divergent flexing of the opposing
film panels,
resulting "peeling" forces from the panels to the spout are also imparted to
the SDF,
thereby reducing the imparted forces to the panels. Thus, the geometry of the
SDFs is
such that a weld between the spout and the panel experiences reduced peel
stress in
favor of shear stress. The remaining peel stress is generally directed to the
spout itself,
which is considerably stronger than the film.
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Desirably, SDFs according to several invention embodiments do not have a
constant
longitudinal profile, nor necessarily a linear edge. A tapered form,
preferably comprising
a curvilinear edge, appears to most effectively delocalize forces that would
otherwise be
directed to the spout weld interface.
The prior art heavily relies upon spouts that have a generally rigid body,
which is
desirable at the spout neck portion where a cap may be fitted, but causes
localized
stress and abrasion of the flexible film panels when and where bonded thereto.
Selected embodiments of the invention may also therefore include spout edges
and/or
portions of the spout weld interfaces that are flexible in comparison to the
neck portion
of the spout. Such an arrangement significantly reduce stress and abrasion of
the film
panels in this area by permitting portions of the spout to flex in response to
flexing of the
film panels, as opposed to localizing stresses at the spout weld interface
periphery.
This flexing ability also constitutes a form of an SDF.
DESCRIPTION OF THE DRAWINGS
Fig. I is a perspective view of a first embodiment of the invention shown
welded
to a flexible fluid container;
Fig. 2 is a side elevation view of the first embodiment of the invention with
alternative weld interface treatments, the left side-illustrating a spout weld
interface
comprising a plurality of negative relief elements and the right side
illustrating a spout
weld interface comprising a plurality of holes;
Fig. 3A is a cross section taken substantially along the lines 3A-3A in Fig.
2;
Fig. 3B is a cross section taken substantially along the lines 3B-3B in Fig.
2;
Fig. 4 is an end elevation view of the first embodiment;
Fig. 5 is a perspective view of a second embodiment of the invention;
Fig. 6 is a side elevation of the second embodiment;
Fig. 7 is an end elevation view of the second embodiment; and
Fig. 8 is a bottom plan view of the second embodiment.
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DESCRIPTION OF INVENTION EMBODIMENTS
Preface: The terminal end of any numeric lead line in the several drawings,
when
associated with any structure, reference or landmark described in this
section, is
intended to representatively identify and associate such structure, reference
or
landmark with respect to the written description of such object. It is-not
intended, nor
should be inferred, to delimit or define per se boundaries of the referenced
object,
unless specifically stated as such or facially clear from the drawings and the
context in
which the term(s) is/are used. Unless specifically stated as such or facially
clear from
the several drawings and the context in which the term(s) is/are used, all
words and
visual aids should be given their common commercial and/or scientific meaning
consistent with the context of the disclosure herein.
Turning then to the several drawings, wherein like parts are are numbered the
same, and more particularly to Figs. 1-4, a first embodiment of the invention
is shown.
Here, spout 10 includes neck portion 20 having external threads 26 formed on
outer
surface 24 thereof. Neck portion 20 further includes portions 28 that comprise
part of
spout weld interfaces 30.
Spout weld interfaces 30 generally include extensions 32a and 32b, each having
spout weld interface surfaces 34a and 34b. These surfaces, in conjunction with
neck
portions 28, form the entirety of the surface that is bonded or welded to
opposing film
panels 82a and 82b of reservoir 80. Each extension 32 further includes
peripheral
edges 36 and converging edge 38. It should be noted that peripheral edges 36
and
adjacent portions of spout weld interfaces 30 are somewhat flexible in that
they are able
to converge and diverge relative to each other; this is a result of not having
any
spanning or structural element restricting such movement. This ability to flex
relative to
neck portion 20, for example, provides one means for reducing stress and
abrasion to
film panels 82a and 82b at film weld interfaces 90, and therefore constitutes
a form of a
Stress Delocalization Feature or SDF.
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Returning to spout weld interface surfaces 34a and 34b, Figs. 3, 3A and 3B
illustrate several forms in which these surfaces may exist. In addition to a
smooth
surface, spout weld interface surfaces 34a and 34b may also comprise negative
relief
features 40 such as a plurality of dimples 42 or holes 44. These negative
relief features
provide a means for beneficially mitigating the effects of gas(es) trapped
between
opposing film panels 82a and 82b of reservoir 80 and spout weld interface
surfaces 34a
and 34b during the welding/bonding process and/or providing a location for
material
displacement resulting from such process.
The embodiment shown in Figs. 1-4 further comprises flexible appendages 50,
each having extending body portion 52, which is linked to extensions 32 via
hinge
element 54, and curvilinear periphery 56. Opposing film panels 82a and 82b of
reservoir 80 may or may not be bonded to appendages 50; in either instance, if
hydrostatic pressure within reservoir 80 causes opposing film panels 82a and
82b to
diverge, then extending body portions 52 will pivot about hinge elements 54
and
maintain contact with the panels. As a consequence, separation forces that
otherwise
would be solely directed to the panels, which would cause localization of
peeling forces
at peripheral edges 36, is dispersed partly to flexible appendages 50 which in
turn
compressively coact against portions of opposing film panels 82a and 82b that
otherwise would not be affected. In this manner, flexible appendages 50
function as
SDFs.
In Figs. 5-8, a second embodiment of the invention is shown that is
substantially
similar to the first illustrated embodiment, except that flexible appendages
50' are
positioned proximate to portions 28 of neck portion 20. Because flexible
appendages
50 or 50' are intended to function as SDFs, greatest benefit there from can be
achieved
with such appendages are positioned at or adjacent to portions of spout weld
interfaces
30 that are less flexible than other portions thereof. In many instances, the
least flexible
portions of spout weld interfaces are at converging edges 38 or portions 28.
In this
second embodiment, flexible appendages 50' are positioned at or adjacent to
portions
'28 (in the first embodiment, flexible appendages 50 were positioned at or
adjacent to
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edges 38). Burst test data have shown that similar stress delocalization
occurs in the
second embodiment when compared to the first. In most other respects, the two
embodiments are similar.
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