U.S. patent number 3,581,941 [Application Number 04/861,513] was granted by the patent office on 1971-06-01 for pressurized container.
This patent grant is currently assigned to Sterigard Company. Invention is credited to John K. Bruce, Theodore R. Bruce.
United States Patent |
3,581,941 |
Bruce , et al. |
June 1, 1971 |
**Please see images for:
( Certificate of Correction ) ** |
PRESSURIZED CONTAINER
Abstract
The pressurized container has a cylindrical rigid body closed at
its top and bottom. A flexible, elastic bag is disposed within the
container with its top clamped by a seam formed between the body
and a covering cap. The flexible bag has a sealed end proximate the
bottom of the body which is arched, with the apex of the arch being
at the centerline of the body and with the arch's sides extending
down towards the bottom of the body. The space between the bottom
of the container and the arch provides a volume for charging the
container with a propellant. A dispensing valve is attached to the
cap in communication with the interior of the bag on the other side
of the propellant chamber.
Inventors: |
Bruce; John K. (Burbank,
CA), Bruce; Theodore R. (Burbank, CA) |
Assignee: |
Sterigard Company (Burbank,
CA)
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Family
ID: |
27068975 |
Appl.
No.: |
04/861,513 |
Filed: |
September 26, 1969 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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697857 |
Jan 15, 1968 |
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548963 |
May 10, 1966 |
3393842 |
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Current U.S.
Class: |
222/95;
222/402.22 |
Current CPC
Class: |
B65D
83/62 (20130101); B65D 83/38 (20130101); B65D
2231/004 (20130101) |
Current International
Class: |
B65D
83/14 (20060101); B67d 005/38 () |
Field of
Search: |
;222/95,105,386,381,386.5,402.22 ;220/63,67 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Reeves; Robert B.
Assistant Examiner: Stack; Norman L.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation of Ser. No. 697,857 now abandoned, and which
in turn is a continuation-in-part of Ser. No. 548,963 now U.S. Pat.
No. 3,393,842.
Claims
What I claim is:
1. An improvement in a container for dispensing pressurized fluid
products comprising:
a. a rigid, right cylindrical, hollow body portion having a right
cylindrical interior wall;
b. a bottom portion closing the bottom of the body portion;
c. a cover seamed to the top of the body portion, the cover being
adapted to mount a selectively actuatable dispensing valve in fluid
product communication with the interior of the body portion;
d. valve means on the bottom portion disposed on the longitudinal
axis of the container for allowing a propellant injection needle to
pass into the hollow interior of the body portion to inject a
propellant therein and for sealing the hollow interior of the body
portion after the injection needle is withdrawn; and
e. an elastic, flexible bag disposed within the body portion, the
bag having a sealed end proximate the bottom portion and an open
end proximate the cover, the sealed end defining a straight line
before disposal in the body portion, the open end of the bag being
clamped between the top of the body portion and the cover in the
seam such that the interior of the bag faces the top portion and
defines a product volume for a fluid product to be dispensed, the
sealed end of the bag being arched, the apex of the arch crossing
the longitudinal axis of the container and being spaced from the
valve means on the bottom portion to provide a space between the
bag and the bottom portion for a propellant injection needle, the
sides of the arch extending from the apex towards the bottom
portion to define a propellant chamber between the bottom portion
and the exterior of the arch and product volumes bordered by the
interior surface of the sides of the arch and the interior surface
of the bag radially of the sides of the arch, the bag at least
between about the apex of the arch and its open end being
contiguous with the interior wall of the body portion, the bag,
including the arch, being capable of collapsing towards the
longitudinal axis of the dispenser as a fluid product in the
product volume is discharged from the dispenser.
2. The improvement claimed in claim 1 wherein the apex of the arch
extends as a line laterally across the seam, each side of the arch
being generally triangular in shape with the apex at the base of
the triangular sides and the seam extending generally normal to the
apex to the tips of the triangular sides.
3. The improvement claimed in claim 2 wherein the seamed connection
between the top of the body portion and the cover is formed by
interlocking the two with a reverse bend of the top of the body and
a double reverse bend of the edge of the cover, the open end of the
bag being sandwiched between the edge of the cover and the top of
the body for the full circumferential extent of the seamed
connection so that the open end of the bag lies in direct tensioned
contact with the unbent exterior surface of the body.
4. The improvement claimed in claim 2 wherein a portion of the bag
extends from the seam joining the cover and the body portion down
the exterior surface of the body portion is direct tensioned
contact therewith.
Description
BACKGROUND OF THE INVENTION
The present invention relates to self-dispensing containers of the
pressurized type and, more in particular, to a pressurized
container employing a bag between the source of pressure and the
products to be dispensed.
Products are often marketed in self-dispensing containers commonly
referred to as "aerosol" containers or bombs. These containers are
rigid cylindrical cans filled with a mixture of the product to be
dispensed and a propellant. The container is provided with a
finger-actuated valve which, when operated, dispenses a mixture of
the product and the propellant. The pressure of the propellant
provides the dispensing force.
Such dispensers are only useful where propellant is readily
miscible with the product. The propellant and product are always
combined which results in a change of product characteristics and
performance. In the dispensing of most items it is difficult to
combine the product and propellant and retain required product
characteristics. In food products the required texture and flavor
cannot be produced. Catsup, for example, becomes a pink foam.
Moreover, many products are not suitable for pressurized dispensing
because of chemical interaction between the product and the
propellant or the product and its metal container.
To overcome the problems inherent with a propellant and a product
in the same chamber, several concepts have been proposed to
separate the product and the propellant. One such concept envisions
a piston between a product and propellant chamber. The chamber
volume occupied by the piston is considerable, often reaching 50
percent of the total container volume. In addition to the cost of
providing a piston and the waste space, the container must be of an
expensive extruded type to present a smooth and continuous wall for
the piston. This is necessary to provide relatively free piston
movement and a sealing surface to reduce excessive product seepage
into the propellant. Because of the required fit between the piston
and wall, any dents in the container wall render the dispensing
device inoperative. Moreover, a high pressure propellant is
necessary with this type of container because of piston friction.
High pressure propellants increase the hazard of explosion and the
amount of propellant required. In addition, only highly viscous
products may be used with this type dispenser because the product
is required to seal the product chamber from the propellant
chamber.
Pressurized dispenser concepts also include diaphragm and sack-type
dispensers. These concepts have not been accepted because of
substantial problems in manufacture, difficulties in operation and
excessive cost.
A problem with pressurized dispensers having separate product and
propellant chambers is in providing space for charging the
propellant without compromising product volume. Propellant is
charged through the bottom of the dispenser by inserting a gassing
needle into the propellant chamber. This needle must have enough
clearance space to avoid rupturing the chamber's separator. It has
therefore been proposed to form the chamber's separator such that
it lies normal to the dispenser's axis, considerably above the
propellant entrance point. The separators have, then, generally
taken the shape of a disc. This type of separation results in a
considerable loss of product volume.
In summary, it is highly desirable to separate the propellant from
the product. Separation should be accomplished with a minimum
expenditure of space for the separating means. Moreover, it is
highly desirable to provide a pressurized container having a large
volume devoted to product space and a relatively small volume
devoted to propellant while allowing for propellant charging. These
requirements should be met with a minimum of manufacturing
costs.
SUMMARY OF THE INVENTION
The present invention provides a pressurized container with
separate propellant and product chambers that maximize product
chamber size while providing ample room for the propellant-charging
needle.
The present invention provides an elastic, flexible bag disposed
within the body portion of a pressurized container. The bag is
sealed at one of its ends and open at its other end. The sealed end
is disposed proximate the bottom end of the body while the open end
is attached to the container such that the interior of the bag is
in product communication with a dispensing valve used to discharge
product.
The sealed end of the bag has an arched configuration. The apex of
the arch lies at the longitudinal axis of the container. The sides
of the arch extend downwardly from the apex towards the bottom of
the container to define a propellant chamber between the closed
bottom and the exterior surfaces of the arch. The propellant
chamber is thus somewhat wedge-shaped allowing a propellant
injection needle to pass into the chamber without rupturing the
bag. The interior of the bag proximate its sealed end is
saddle-shaped because of the arch. Additional product volume
between the interior surfaces of the arch's walls and the proximate
lateral surfaces of the bag is therefore available.
In specific form, the arched configuration of the bag has the apex
of the arch intersecting and crossing approximately normal to the
end's seal. The sides of the arch are generally triangular in shape
with the base for the triangular sides meeting at the apex. The
seam defined by the sealed end then extends as a broad V across the
apex and terminates at the tip or apex of the triangular side
portions.
Preferably the pressurized container is closed at its top by a
double-seamed connection between a dome-shaped cover or cap and the
top of the body portion. The double seam is defined by a reverse
bend of the top of the body and a double reverse bend of the edge
of the cap. The bag is sandwiched between the edge of the cap and
the top of the body. for the full circumferential extent of the
seamed connection so that the open end of the bag lies in direct
tensioned contact with the unbent exterior surface of the body.
The pressurized dispenser of the present invention provides a
product dispenser which has separate product and propellant
chambers. Therefore, the problems of product-propellant
compatibility, product characteristics and product performance are
avoided. The bulk of the product chamber is defined by the interior
sidewalls of the bag and therefore container-product compatibility
is not a problem. Because the product is contained in a bag, the
concern with product-propellant sealing experienced with pistons is
overcome. MOreover, standard container bodies having side seams may
be used without affecting the operation and reliability of the
dispenser. This means that standard, economical production
facilities are readily adaptable to fabricate the dispenser of the
present invention.
The arched configuration of the bottom of the bag provides a
wedge-shaped propellant chamber that maximizes the amount of
product which can be placed in a given size dispenser. The apex of
the arch provides room for the passage of a propellant injection
needle. The bag, however, extends downwardly from its apex to
provide additional product volume. The arched configuration of the
bag provides another salutory feature. This feature resides in the
collapsing of the bag as product is withdrawn from the dispenser.
It has been found that with the arched type configuration islanding
of product is avoided. Islanding refers to the trapping of product
by the collapsing bag into pockets which are out of communication
with the dispensing valve. Another advantage attendant with the
arched configuration of the present invention resides in its
reliability. Typically, bags are formed of extruded plastic tubing
closed at one end by a heat seal. If the closed bottom of the bag
were formed by a separate piece such as a disc, leakage becomes a
problem because of difficulty in the seaming operation and the
length of the seam.
In addition, it has been found that a much smaller amount of
propellant is needed with this dispenser because none of the
propellant is exhausted through the dispensing valve as the product
is dispensed. Thus the container will hold more product and less
propellant. It has also been found that only a small amount of
propellant pressure is needed to obtain satisfactory discharge of
the product. This pressure, which may be in the neighborhood of 5
to 10 p.s.i., means there can be a reduction in the strength
requirements of the container which makes possible the use of less
expensive containers. The danger of container explosion by
inadvertent exposure to heat is also reduced because of the low
pressure.
These and other features, aspects and advantages of the present
invention will become more apparent from the following description,
appended claims and drawings.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is an elevational view, partly in half section, of the
preferred form of the dispenser of the present invention;
FIG. 2 is an enlarged fragmentary view of area 2- 2 of FIG. 1;
FIG. 3 is a perspective view of the bag of the present invention in
its open condition;
FIG. 4 is a view of the bag of the present invention in a flat
condition;
FIG. 5 is a cutaway perspective view of the dispenser showing the
top portion of the dispenser and the bag in its fully extended
position;
FIG. 6 is a perspective view similar to FIG. 5 showing the
product-containing bag in a collapsed position; and
FIG. 7 is a perspective view of the container in a fully assembled
condition.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 7 illustrate the preferred form of a dispenser 10. The
dispenser has three main portions: A cylindrical body portion of
rigid tubing 12, a cover or cap portion 14 and a bottom portion 16.
The cover and bottom portions are double seamed to body portion 12
at seams 18 and 20, respectively. A flexible bag of elastic
material 22 is disposed within container 10 and is held in place in
the container by seam l8. The bag has an arched bottom portion 24
disposed above bottom portion 16. A dispensing valve 26 of standard
construction except for a valve extension 28 is in product
communication with the interior of flexible bag 22. A valve cup 30
carries dispensing valve 26 on cover l4.
Cap or cover portion l4 has a bead rim 32 over which an annular
flange 34 of valve cup 30 is crimped. Valve 26 is mounted in valve
cup 30 through a rubber sealing and mounting member 36. Valve 26
includes a stem portion 38 which has a longitudinally disposed
product passage 40. The product passage terminates at valve
extension 28. Valve extension 28 has a conelike configuration and
includes a generally flat sealing surface 42. Stem 38 has an
annular flange 44 which bears against the upper edge of sealing
member 36. Sealing member 36 is compressed slightly between flange
44 and sealing surface 42 to seal the contents of bag 22 from
passage 40, the contents being shown by the crosshatching
interiorly of bag 22 in FIG. 1. A plurality of circumferentially
disposed ports 46 in stem 38 communicate passage 40 with the
exterior of the stem. Horizontal finger pressure on stem 38 breaks
the seal between mounting member 36 and sealing surface 42 to admit
product through ports 46 into passage 40 for discharge.
Bottom portion 16 is a dishlike member having its convex side
facing the interior of body portion 12. A self-sealing valve 48 of,
for example, a catalyzed polyester compound, is mounted on the
interior upper surface of bottom portion 16. Self-sealing valve 48
admits to the passage of propellant into the interior of body
portion 12 by a needle. The self-sealing valve may be conically
shaped in order that the radical pressure exerted by the propellant
on the deposit will give maximum sealing as a gassing or
pressurizing needle is inserted through the valve to charge the
container and is withdrawn through the valve after completion of
propellant charging. Arched portion 24 admits to the insertion of a
charging needle because its apex is disposed sufficiently above
self-sealing valve 48 to prevent puncture of the bag during the
propellant-charging process.
FIG. 2 illustrates the manner in which flexible bag 22 is affixed
to container 10. Cover 14 is mounted on body portion 12 through
double seam 18. This double seam is defined by a single reverse
bend of body portion 12 and a double reverse bend of cap 14. Before
the seaming, body portion 12 has a radially extending flange over
which the top of the bag is stretched. A portion of the bag extends
down the exterior wall of body portion 12. This portion is shown by
reference numeral 50. During the seaming operation flange 52 of
cover or top portion 14 is bent back upon itself with a portion of
flange 54 of body portion 12 being bent downwardly at the same
time. Flange 52 tucks inside the downward extension of flange 54
and up against external portion 50 of bag 22. The affixed end of
bag 22 is disposed between the seamed flanges such that it doubles
back on itself and then down the outside of body 12. The seal of
the bag effected with this double seam is considerable because of
the large clamped area. The stretching of the bag over the mouth of
the body and tightly down its external side avoids gathering,
doubling or twisting while forming seam 18. Any separation or
tearing of bag material during seaming is normally localized
because of the large clamped area, thereby avoiding the loss of the
seal. MOreover, the tensioned contact of portion 50 over the top
and down the external sidewall of the body portion 12 prevents the
bag from being pushed back into the interior of body portion 12
during the seaming operation.
FIGS. 3, 4 and 5 depict the bag in detail. Flexible bag 22 is
normally fabricated from commercially available rolled tubing which
comes in a flattened configuration as depicted in FIG. 4. This
tubing is inexpensive and is readily prepared for use in the
dispensing container of the present invention. It has the further
advantage that no side seam is required which might affect the seal
in seam 18. The dimension of the perimeter of the flexible bag is
selected such that it is approximately the same as the inner
perimeter of body portion 12. When inserted and affixed in
container 10, flexible bag 22 takes a generally cylindrical
configuration down to arched portion 24 to conform to the interior
configuration of body 12.
The tubing is heat sealed at one end either before or after it is
cut from its roll. The heat-sealed end is indicated by reference
numeral 56. If desired, printed indicia 57 can be placed on the
tubing stock. The end opposite the seal end 56 is left open as
indicated by reference numeral 58. The open end is expanded and
slipped over the mouth at the top end of body portion 12 and then
relaxed. This allows the tubing to contract against the exterior,
upper portion of the body portion. The exterior portion 50 of the
bag adheres to the exterior of the body in skinlike elastic
contact. This exterior portion of the bag, if not removed in the
manufacturing process, may be used to identify the dispenser. In
addition, it may be useful as an advertising area for the product
manufacturer while being removable by the user for decorative
purposes. Thus, the exposed exterior portion of the bag may be
preprinted and made to any suitable length.
Product-containing bag 22 may be fabricated from extruded
polyethylene tubing having a relatively thin wall thickness, for
example, 0.002 inch. A bag formed of polyethylene or similar
plastic materials has the advantage that it undergoes very little
expansion during its filling. This enhances the measure accuracy
for the product placed in the dispenser.
The physical characteristics of the bag are important. The material
should have good "memory" characteristics for its contraction into
intimate contact with the outer wall of the body portion and the
encompassed flange. This avoids bunching which affects the seal in
seam 18. The material must have a relatively high hardness to avoid
squeezing or thinning during seaming and, therefore, separation.
The bag material should accept a heat seal and have good barrier
characteristics to avoid product-propellant communication. When
filled with product, the bag should not expand, that is, the bag
should have good filling resistance. The material should admit to
extrusion to avoid a longitudinal heat seal. In addition, the
material should be able to withstand relatively high product
filling temperatures while not exhibiting brittleness from the low
temperature effects of propellant charging.
As previously indicated, the open end of bag 22 is affixed in the
container by its clamping in seam 18. The open end of the bag thus
takes a circular configuration. The bag, however, is initially
formed of flat stock. The heat-sealed bottom end 56 prevents this
end from assuming a cylindrical configuration. By virtue of the
fact that the perimeter of bag 22 is only slightly less than the
interior perimeter of body 12, the bag is constrained against
flaring outwardly of the interior diameter of the body. The
constraining influence of the can together with seam 56 produces
arched configuration 24.
The arched configuration is best seen in FIG. 5. Sealed end 56
describes a broad based "V." The apex of arch 24, indicated by
reference numeral 60, extends laterally across seam 56 at
approximately a right angle. A pair of generally triangular sides
62 and 64 are thus formed. The interior of tube 22 bounded by these
triangular sections define two product chambers in open
communication with the balance of the interior of bag 22. The bag
in its installed condition is generally cylindrical at its top and
remains so until the arched portion is reached. The extreme radial
walls of the bag in the arched portion generally conform to the
interior geometry of the can, that is, they take a generally
cylindrical configuration.
The assembly operation of the present dispenser will now be
described. After product-containing bag 22 has been formed and
placed over body portion 12, the bag is drawn into the body by
drawing a low vacuum at its bottom open end. Top portion 14 is now
seamed to the top of body portion 12 to form seam 18 as depicted in
FIG. 2. Bottom portion 16 is then seamed to the bottom of body
portion 12 to effect seam 20 in a manner similar to that which
formed seam 18. To complete the packaging operation, dispenser 10
is filled with product through the hole which receives valve cup
30. The dispenser is then ready for attachment of valve cup 30 and
its carried dispensing valve 26. Valve cup 30 is crimped at a
plurality of locations around the circumference bead rim 32. A
propellant injection needle is then positioned beneath the
dispenser and caused to pass through valve 48 to introduce any one
of a number of commonly used propellants such as
octafluorocyclobutane (commonly referred to as food grade C 318
Freon). The dispenser is now ready for shipment to the
consumer.
Product dispensing is normally accomplished in the following
manner. The product within flexible bag 22 is in communication with
valve 26. A propellant is disposed in the propellant chamber
outside the bag between arch portion 24 and the upper surface of
bottom portion 16. Stem 38 of valve 26 is displaced laterally of
opening ports 46 to the interior of bag 22. Product will then flow
through passage 40. When the valve is operated, pressure from the
propellant is exerted on the exterior surfaces of bag 22. This
pressure causes the bag to collapse toward the longitudinal axis of
the container forcing the product through valve 26. Longitudinal
collapsing continues for a time. Because. Because bag 22 is
attached to the container at seam 18, the portions of the bag
closest to the top of the container will begin to collapse towards
the interior surface of top portion 14. The bag will follow the
outline of the interior of this portion, whether it be domed or
flat. The pressure from the propellant causes the product to be
squeezed towards valve extension 28 in the center of container 10.
As further amounts of product are dispensed, the bag, still feeling
the pressure of the propellant, eventually reaches the
configuration depicted in FIG. 6. Very little product volume is
left in this configuration.
Bag 22 being of filmlike consistency offers very little resistance
to propellant pressure and therefore collapses substantially
completely about valve extension 28. The arch configuration of bag
22 in conjunction with valve extension 28 prevents islanding or
isolation of product in pockets out of communication with valve 26.
If the bottom of bag 22 were a flat disc circumferentially sealed
to the balance of the bag, islanding would be a severe problem
because in this case the resistance offered by the seam forces
preferential collapsing interiorally of the bottom against the
longitudinal walls of the bag.
* * * * *