U.S. patent application number 12/799298 was filed with the patent office on 2012-12-20 for pressurized dispencer with controlled release of stored reserve propellant.
Invention is credited to Walter K. Lim.
Application Number | 20120318830 12/799298 |
Document ID | / |
Family ID | 47352879 |
Filed Date | 2012-12-20 |
United States Patent
Application |
20120318830 |
Kind Code |
A1 |
Lim; Walter K. |
December 20, 2012 |
Pressurized dispencer with controlled release of stored reserve
propellant
Abstract
A gas storage and delivery system for restoring pressure as it
is depleted from a pressurized container stores a reserve supply of
propellant gas on a gas-adsorbing material. The propellant gas is
released into the container in response to a decrease in pressure
in the container to maintain a desired pressure as product is
depleted. The gas-adsorbing material is wetted with a non-polar
release-promoting agent to promote release of the sorbed gas in
response to decreases in pressure in the container and to ensure
that substantially all of the sorbed gas is obtained if needed in
response to decrease in pressure in the container.
Inventors: |
Lim; Walter K.; (Rancho
Santa Fe, CA) |
Family ID: |
47352879 |
Appl. No.: |
12/799298 |
Filed: |
April 21, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61214215 |
Apr 21, 2009 |
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Current U.S.
Class: |
222/402.1 ;
222/389; 222/394; 53/400 |
Current CPC
Class: |
B65D 83/663 20130101;
B65D 83/64 20130101; B65B 31/10 20130101; B65D 83/62 20130101 |
Class at
Publication: |
222/402.1 ;
53/400; 222/394; 222/389 |
International
Class: |
B65D 83/00 20060101
B65D083/00; B65B 29/00 20060101 B65B029/00 |
Claims
1. A gas storage and delivery system for restoring pressure as it
is depleted from a pressurized container, comprising: a container
holding a product under pressure to be dispensed from the
container, said container having a normally closed discharge valve
through which said product is dispensed when the valve is opened; a
quantity of propellant comprising a gaseous material under pressure
in the container, occupying a space in the container and applying
to the product a predetermined pressure of from about 30 to about
180 psig to discharge product from the container when the valve is
opened; a quantity of gas-adsorbing material in the container; a
reserve supply of gaseous material adsorbed on the gas-adsorbing
material, said reserve supply of gaseous material being desorbed
from the gas-adsorbing material and released into the container in
response to a decrease in pressure in the container, thereby
restoring and maintaining a predetermined pressure in the container
as product is depleted from the container; and wherein said
gas-adsorbing material is wetted with a non-polar release-promoting
agent to promote release of the sorbed gas in response to decreases
in pressure in the container, and wherein release of substantially
all of the sorbed gas is obtained if needed in response to decrease
in pressure in the container.
2. A gas storage and delivery system as claimed in claim 1,
wherein: the gas adsorbing material is selected from the group
consisting of activated carbon, natural or synthetic zeolite,
alumina, and a carbon fiber composite molecular sieve.
3. A gas storage and delivery system as claimed in claim 1,
wherein: the gaseous material is selected from the group consisting
of carbon dioxide and nitrous oxide.
4. A gas storage and delivery system as claimed in claim 1,
wherein: the gas adsorbing material is in the form of a one-piece
cohesive body of material that retains its shape in the container
and prevents dispersal of the material throughout the product.
5. A gas storage and delivery system as claimed in claim 1,
wherein: the gas adsorbing material is a granular or powdered
material.
6. A gas storage and delivery system as claimed in claim 5,
wherein: a film or membrane cover is placed around the gas
adsorbing material to prevent dispersal of it into the product but
to enable flow of the stored gaseous material from the gas
adsorbing material into the product.
7. A gas storage and delivery system as claimed in claim 6,
wherein: the film or cover prevents contact between the gas
adsorbing material and the product.
8. A gas storage and delivery system as claimed in claim 1,
wherein: the non-polar fluid comprises mineral spirits; and the
non-polar fluid is added to the container in the ratio of from
about 10% to about 90%, by weight, of non-polar fluid to adsorbent
material.
9. A gas storage and delivery system as claimed in claim 1,
wherein: the non-polar fluid comprises isoparaffin; and the
non-polar fluid is added to the container in the ratio of from
about 10% to about 90%, by weight, of non-polar fluid to adsorbent
material.
10. A gas storage and delivery system as claimed in claim 1,
wherein: the sorbent material is contained within an envelope made
of a material that is impermeable to the propellant gas and to
moisture vapor and to the product to be dispensed, said envelope
being perforated to enable passage therethrough of the sorbed gas
and product but precluding passage therethrough of the sorbent.
11. A gas storage and delivery system as claimed in claim 10,
wherein: the envelope material comprises a heavy foil laminated
with a polyethylene film.
12. A gas storage and delivery system as claimed in claim 1,
wherein: the sorbent is sealed in a gas-permeable membrane that
permits passage of the gaseous material but precludes passage of
the product.
13. A gas storage and delivery system as claimed in claim 1,
wherein: the propellant comprises carbon dioxide and is placed in
the container in the form of dry ice that melts to form the gaseous
propellant and pressurize the container.
14. A gas storage and delivery system as claimed in claim 1,
wherein: the sorbent is loaded with propellant gas and pre-wetted
with the non-polar fluid prior to being placed in the
container.
15. A process of filling and pressurizing a dispensing container
for dispensing a product pressurized by a propellant gas in the
container, comprising the steps of: placing a desired quantity of
gas-adsorbing material in the container; wetting the sorbent with a
non-polar fluid; closing and sealing the container; pumping a
predetermined quantity of propellant gas into the container; and
injecting product into the container.
16. A process of preparing a dispensing container for dispensing
product under pressure from a pressurized gaseous propellant,
comprising the steps of: placing a gas-adsorbing material in a
storage container or drum flooded with a propellant gas at
substantially atmospheric pressure and temperature so that the
sorbent material can be stored and shipped in bulk quantities to a
point of use without becoming contaminated and gas adsorbed on the
sorbent is not desorbed; at a filling location placing a desired
quantity of the sorbent in a dispensing container to be pressurized
with the propellant gas and filled with product; closing and
sealing the dispensing container and pumping additional propellant
gas into the dispensing container so that a desired pressure is
achieved when product is added later; and adding product to the
container and shipping the filled and pressurized container to a
point of sale or use.
17. A process as claimed in claim 16, wherein: the sorbent is
pre-wetted with a non-polar fluid before it is placed in the
dispensing container.
18. A process as claimed in claim 16, wherein: the sorbent is
wetted with a non-polar fluid after the sorbent is placed in the
dispensing container by injecting an appropriate amount of the
non-polar fluid into the container and into contact with the
sorbent.
19. A process as claimed in claim 16, wherein: the sorbent is
wetted with a non-polar fluid prior to placing it in the storage
container.
Description
[0001] This application claims the benefit of U.S. provisional
patent application Ser. No. 61/214,215, filed Apr. 21, 2009.
TECHNICAL FIELD
[0002] This invention relates to containers that dispense product
under pressure. More particularly, the invention relates to
pressurized dispensers that use a propellant gas to exert pressure
on or with the product to dispense it through a valve when the
valve is opened, and specifically to a container that stores a
reserve supply of gaseous propellant adsorbed on a gas adsorbing
material in the container and releases the stored gaseous
propellant into the container to maintain a desired pressure level
in the container as product is depleted.
BACKGROUND ART
[0003] Many products are packaged in so-called pressure pack
dispensers that hold under pressure a propellant and a product to
be dispensed. Propellants normally comprise either a liquefied gas
dissolved in the product, or a compressed gas injected into the
container to exert pressure on the product.
[0004] The amount of liquefied gas or compressed gas and the
pressure at which they are pumped into the container are calculated
to achieve a desired starting and ending pressure in the container.
In those containers using a liquefied gas as the propellant, as
product is depleted the pressure in the container drops and some of
the liquefied gas gasifies to restore the equilibrium pressure.
This action will continue as long as there is sufficient liquefied
gas in the container to gasify and restore the pressure to a
desired pressure, for example the starting equilibrium pressure. In
those containers using a compressed gas as the propellant, as
product is depleted the compressed gas expands to fill the space
vacated by the dispensed product. As the compressed gas expands,
the pressure exerted by it decreases according to Boyle's law,
which states that pressure is inversely proportional to volume.
Since there is nothing to restore or replenish the pressure of the
expanded compressed gas, the pressure in the container falls
dramatically as product is used up. To ensure that adequate
pressure will remain when the container is being utilized or nearly
empty of product it is generally necessary to start with a pressure
that is higher than required to achieve desired discharge
characteristics. Accordingly, for performance reasons liquefied gas
propellants are generally preferred over compressed gas, even
though compressed gases are generally environmentally friendly
while liquefied gases are not.
[0005] At one time Freon.RTM., a fluorinated hydrocarbon, was the
most common aerosol propellant, but its use has been banned because
it is believed to contribute to destruction of the ozone layer.
Similarly, the use of chlorofluorocarbons (CFCs) has been banned
because of their harm to the environment. Since the ban of these
substances the majority of aerosol propellants have been based on
light hydrocarbons or hydrofluorocarbons. However, these volatile
organic compounds (VOCs) form atmospheric contaminants and are also
now the subject of legislation and increasing pressure from the
environmental lobby.
[0006] Compressed gases such as carbon dioxide, nitrogen, and air
are ideal in concept for use as an aerosol propellant because of
their limited impact on the environment, but the reduction in
operating pressure over the life of the dispenser poses a serious
drawback to their use. Carbon dioxide (CO.sub.2), for example, is a
desirable propellant because it is plentiful and non-flammable.
However, its use has been limited in aerosol products because the
solubility of CO.sub.2 in the product media is low, whereby
sufficient CO.sub.2 cannot be placed in the container to maintain a
desirable pressure throughout the useful life of the dispenser.
[0007] In conventional aerosol dispensers utilizing compressed
gases as the propellant, a compressed gas is placed in the
container in an amount and at a pressure calculated to achieve
satisfactory discharge of the product throughout the useful life of
the dispenser, i.e. until all or substantially all product has been
discharged. Since the pressure will drop off as the product is
depleted, and only a finite amount of propellant is initially
placed in the container, the pressure varies considerably over the
useful life of the container. As a result, the characteristics of
the discharge spray may vary considerably over the useful life of
the container. Also, product volume is limited to 60-65% of the
container volume in order to have enough propellant gas in the
container to provide enough pressure to perform during dispensing
of the last 25% of product
[0008] Efforts have been made in the prior art to solve the
foregoing problems and enable use of environmentally friendly
compressed gases. In one such prior system a quantity of
gas-adsorbing material such as, e.g., activated carbon or zeolite
on which is adsorbed a reserve supply of propellant gas such as,
e.g., carbon dioxide, is placed in the container, or in
communication with it. In these systems gas will be released or
desorbed from the sorbent material to restore or replace the
expanded compressed gas and maintain pressure in the container at a
desired level as product is depleted. It is intended that as
product is depleted from the container and the pressure of the
propellant consequently drops as it expands into the space vacated
by the product, some of the propellant adsorbed on the
gas-adsorbing material will be released into the container to
maintain the pressure at a desired level. In practice, however,
this result is not uniformly and satisfactorily achieved due to the
fact that although activated carbon or zeolite is capable of
adsorbing and storing a large amount of gaseous carbon dioxide, the
gas is not totally desorbed. Consequently, in these prior systems
only a small amount of the adsorbed gas is desorbed, specifically
only about 42%, and made available to maintain the pressure in the
container at a desired level throughout the useful life of the
container.
[0009] Applicant sought to overcome this problem in his prior
patent application serial number 11/250,235, filed Oct. 14, 2005,
published as US-2006/0049215, by wetting the sorbent material with
a polar solvent such as water or alcohol to promote desorption of
more gas from the sorbent material. Normally, wetting the sorbent
material with a polar fluid causes the sorbed gas to be desorbed
more rapidly than desired, initially over-pressurizing the
container and not leaving any reserve gas for release into the
container as product is depleted and the pressure in the container
drops. In its earlier application applicant sought to overcome that
problem by wetting the sorbent with a limited amount of polar fluid
in a reduced concentration, but this was only partially
successful.
[0010] Accordingly, there is need for a pressurized dispenser
holding a product and a propellant gas under pressure in a
container, with a reserve supply of gas adsorbed on a gas-adsorbing
material in the container for release of the reserve gas into the
container in response to pressure drops, and with means to obtain
desorption of the adsorbed gas from the gas-adsorbing material in a
controlled manner and so that substantially all of the sorbed gas,
approximately 80% or more, is eventually desorbed.
DISCLOSURE OF THE INVENTION
[0011] The present invention is a pressurized dispenser holding a
product and a propellant gas under pressure in a container, with a
reserve supply of gas adsorbed on a gas-adsorbing material in the
container for release of the reserve gas into the container in
response to pressure drops, and with means to obtain desorption of
substantially all of the gas in a controlled manner.
[0012] The use of an ionized solid as a sorbent to attract and
store CO.sub.2 in a closed container enables the storage of
CO.sub.2 beyond the capacity that the container would have in the
absence of the sorbent. In a 10 ounce container with one (1) ounce
of the solid sorbent, the quantity of gas at 80 psig is 285%
greater, by weight, than without the sorbent, and the quantity of
gas at 100 psig is 251% greater than without the sorbent. Applicant
has discovered that by wetting the sorbent with a non-polar fluid,
release of the sorbed gas from the sorbent does not occur all at
once but is achieved in a controlled manner, i.e. the sorbed gas is
released in response to decrease in pressure, whereby a desired
equilibrium pressure is maintained in the container until all or
substantially all of the product has been dispensed.
[0013] The preferred sorbent is zeolite (sodium aluminum silicate)
or activated carbon, although the sorbent may comprise any of:
activated carbon, natural or synthetic zeolite, alumina, or a
carbon fiber composite molecular sieve.
[0014] Preferred non-polar solvents have a low vapor pressure and
include, for example, mineral spirits, isoparaffin, and EXXSOL D-95
by ExxonMobil. Other non-polar solvents can be used, depending upon
the requirements and characteristics desired or needed in a
particular application. In some applications very small amounts of
a polar solvent, e.g. water, alcohol or acetone, may be used, alone
or in combination with a non-polar solvent. Polar solvents alone,
unless used in very small amounts as described hereinafter,
generally are not satisfactory since they tend to cause release all
at once of all or substantially all the adsorbed gaseous
propellant. Although a polar solvent is effective to promote
desorption of substantially all the sorbed gas, it does not achieve
controlled release over the useful life of the container.
[0015] In preparing the sorbent in accordance with one aspect of
the present invention, a gas adsorbing material is placed in a
container or drum flooded with a propellant gas to be adsorbed. The
container is at substantially atmospheric pressure and temperature,
and in a preferred embodiment the gas adsorbing material, or
sorbent, is zeolite and the gas to be adsorbed is carbon dioxide.
It should be understood that other sorbents, such as activated
carbon, for example, and other compressed gases, such as nitrous
oxide, for example, could be used. The shipping and storage
container is flooded with the propellant gas that is to be adsorbed
on the sorbent so that the sorbent is exposed to an ambient
atmosphere comprising that gas, so that during storage and handling
prior to use the sorbent is not contaminated and the sorbed gas is
not desorbed. This enables the sorbent to be stored and shipped in
bulk quantities to a point of use. If desired, the gas adsorbing
material can be wetted with a non-polar fluid prior to placing it
in the storage container, or it can be wetted at a later stage in
the filling process, as described hereinafter.
[0016] At the point of use a desired quantity of the sorbent is
placed in a dispensing container to be pressurized with the
propellant gas and filled with product. The sorbent can be
pre-wetted with the non-polar fluid before it is placed in the
dispensing container, or wetted after it is placed in the
dispensing container by injecting an appropriate amount of the
non-polar fluid into the container and into contact with the
sorbent. The dispensing container is closed and sealed and
additional propellant gas is pumped into the dispensing container
so that a desired pressure is achieved when product is added. The
propellant gas can be pumped into the dispensing container through
a plug in the bottom of the container, or under the cup (under cup
gassing) prior to crimping the container closed.
[0017] As product is dispensed and the pressure falls in the
dispensing container some of the sorbed gas is released from the
sorbent into the container to maintain the pressure at a desired
level. Using a sorbent wetted with a non-polar fluid ensures that
substantially all or at least most of the sorbed propellant gas
will be desorbed as needed during use of the container, and the gas
will be desorbed gradually as needed to restore equilibrium
pressure in the container. The non-polar fluid is added to the
zeolite in a ratio of from about 10% to about 90%, by weight, of
non-polar fluid to zeolite, and optimally in the ratio of about 20%
non-polar fluid to zeolite.
[0018] In accordance with another aspect of the invention the
sorbent is saturated or loaded with propellant gas at ambient
pressure and wetted with a non-polar fluid and then sealed in a
packet that prevents contamination of the sorbent and desorption of
the propellant gas from the sorbent. In a preferred embodiment the
packet is a foil pack comprising a lamination of a heavy foil and
polyethylene film. The foil packet is impermeable to the propellant
gas and to moisture vapor and to the product to be dispensed. The
sealed packets can be shipped and stored without loss of propellant
gas from the sorbent. At the point of use one or more of the
packets are placed in a dispensing container to be pressurized with
the propellant gas and filled with product to be dispensed.
Immediately prior to the packets being inserted into the container,
or while they are being inserted, they are perforated in order to
enable the sorbent to adsorb the selected compressed propellant gas
and also so that during use the sorbed gas can be released into the
container to maintain a desired pressure. Perforation of the
packets can be accomplished with lasers or pins or slitters or
other means known in the art. After the perforated packets have
been inserted into the container, a propellant gas is charged into
the container to a desired pressure and under cup sealed, followed
by injecting a desired quantity of product into the container. If
the container is of the barrier pack type wherein the product is
kept isolated from the propellant by, e.g., a piston located
between the propellant and the product, or wherein the product is
placed in a bag, the product can comprise or can include either a
polar fluid or a non-polar fluid. If the product and propellant are
in fluid contact with one another in the container then the product
must comprise only a non-polar fluid. During use of the container,
as product is depleted and pressure in the container falls,
additional propellant gas is released from the sorbent and passes
through the perforations in the foil to restore pressure in the
container. Use of the sealed foil packets simplifies the storage
and handling of the sorbent in that it is not necessary to store
the sorbent in a sealed bulk container having a propellant gas
atmosphere. Smaller filling companies may find the packets more
advantageous to use than the bulk containers described above.
[0019] In an alternate embodiment the sorbent packet can comprise
sorbent pre-wetted with a non-polar fluid and sealed in a gas
permeable membrane that passes only the propellant gas. In this
embodiment the packet can be placed directly in the product whether
the product comprises a polar fluid or a non-polar fluid. However,
unless the packet according to this form of the invention is placed
in the dispensing container immediately after the sorbent is wetted
with the non-polar fluid, it would need to be stored prior to use
in an environment comprising the propellant gas.
[0020] The non-polar solvent causes the sorbed gas to be released
in a controlled manner in response to pressure drops in the
container and most, if not all, of the sorbed gas will be desorbed
during the useful life of the container. In particular, applicant
has found that upwards of 85% of the gas will be desorbed. A ratio
of solvent to zeolite in the range of from about 10% to about 90%,
by weight, has been found by applicant to achieve the desired
results, but optimum results are obtained at a ratio of about 20%
and this is the preferred ratio. The quantity of sorbent material
and the initial quantity and pressure of the propellant gas placed
in the container are selected so that a desired pressure is
maintained throughout the useful life of the container.
[0021] To load the sorbent with compressed propellant gas in
accordance with an embodiment of the invention, the sorbent is
placed in a can (dispensing container) and propellant gas is
introduced under pressure into the can. Applicant has found that
the sorbent becomes fully loaded or saturated, or at least nearly
fully saturated, at a pressure of about 50 psi. Further adsorption
can be achieved by increasing the pressure, but the sorbent is
substantially fully saturated at a pressure of about 50 psi. The
sorbent loaded with propellant gas can then be wetted with a
non-polar fluid and sealed in a container or sealed in a foil
packet or gas permeable membrane, as described above.
[0022] Addition of a polar solvent in the ratio of from about 0.1%
to about 0.5%, by weight, of solvent to zeolite can be satisfactory
under some circumstances.
[0023] The invention is particularly suitable in containers having
a piston or bag that separates the product from the propellant,
commonly referred to as barrier packs.
BRIEF DESCRIPTION OF THE DRAWINGS:
[0024] The foregoing, as well as other objects and advantages of
the invention, will become apparent from the following detailed
description when taken in conjunction with the accompanying
drawings, wherein like reference characters designate like parts
throughout the several views, and wherein:
[0025] FIG. 1 is a longitudinal sectional view of a first form of
pressurized container incorporating the invention, wherein the
container is a barrier pack of the bag-on-valve type.
[0026] FIG. 2 is a longitudinal sectional view of another form of
pressurized container incorporating the invention, wherein the
container is a barrier pack of the piston type.
[0027] FIG. 3 is a longitudinal sectional view of a further form of
pressurized container incorporating the invention, wherein the
product, propellant, and sorbent material are in the container
together.
[0028] FIG. 4 is a perspective view of a foil pack containing a
sorbent saturated with a propellant gas and wetted with a non-polar
fluid in accordance with the invention.
[0029] FIG. 5 is an enlarged fragmentary sectional view of a foil
and polyethylene laminate used in making the foil pack of the
invention.
[0030] FIG. 6 is a longitudinal sectional view of a further form of
the invention wherein solidified CO.sub.2, or dry ice, is used to
introduce the propellant gas into the container.
[0031] FIG. 7 is a perspective view of a sorbent packet wherein the
sorbent is sealed in a gas-permeable membrane.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0032] A first form of pressurized container incorporating the
invention is indicated generally at 10 in FIG. 1. The container
shown in this figure is a so-called barrier pack, more specifically
commonly referred to as a bag-on-valve (BOV) container, and
comprises a container 11, typically made of either metal or
plastic, having a dome or end closure 12 carrying a valve assembly
13 with a bag 14 attached to the valve assembly. A gaseous
propellant 15 is charged into the container outside the bag to
pressurize the container, and product 16 is injected into the bag.
When the valve 13 is opened product will be discharged through the
valve. The structure described thus far is conventional.
[0033] In accordance with one aspect of the invention, a
predetermined quantity of gas-adsorbing material 17, such as, e.g.
zeolite or activated carbon, is placed in the container prior to
assembly of the bag to the container. The valve and bag assembly
are then attached to the container, and gaseous propellant is
charged into the container outside the bag to pressurize the
container and load the sorbent 17 with a reserve supply of the
propellant gas. A non-polar solvent, e.g. mineral spirits,
isoparaffin, or EXXSOL D-95 by ExxonMobil, is then injected into
the container, preferably through the valve plug 19 in the
container bottom, in an amount sufficient to wet the sorbent
material 17 with the solvent. The amount of solvent injected into
the container preferably is in the range of from about 10% to about
90%, by weight, of solvent to sorbent, and preferably in the ratio
of from about 40% to about 50%, and most preferably in the ratio of
about 20%. Product may be injected into the bag either before or
after the solvent is injected into the container. As product is
depleted from the container during use, the pressure drops and some
of the propellant sorbed on the sorbent material is released into
the container to restore equilibrium pressure. As more product is
depleted, more propellant is released. Wetting of the sorbent with
the non-polar solvent ensures that substantially all of the sorbed
gas can be desorbed if needed during use of the container, but the
gas will still be released incrementally in response to incremental
drops in pressure.
[0034] The sorbent material may take any suitable and desired form
or shape as illustrated and described, for example, in applicant's
copending published patent application 2006/0049215, the disclosure
of which is incorporated in full herein by reference.
[0035] Instead of the bag-on-valve container of FIG. 1, the
invention can be used in a piston type barrier pack as shown at 20
in FIG. 2. In this form of the invention the sorbent material 17'
is placed in the container 11' prior to insertion of the piston 18
into the container. It will be noted that in the example shown in
FIG. 2 the sorbent 17' is in the form of a shaped cohesive body
rather than the loose granular material or pellets of FIG. 1. The
piston is then inserted into the container and the top of the
container closed and sealed. Gaseous propellant is then charged
into the container below the piston to pressurize the container and
load the sorbent 17' with a reserve supply of the propellant. As in
the previous embodiment; the sorbent is then wetted with a
non-polar solvent injected through the plug 19 in the bottom of the
container, either prior to or after product is injected into the
container above the piston. Release of the sorbed gas to restore
pressure as product is depleted is the same as in the previous
embodiment.
[0036] A further form of the invention is indicated generally at 30
in FIG. 3. In this form, the propellant 15, product 16 and sorbent
material are all in the same chamber in the container 11'', and the
sorbent material is contained in a foil pack 31. As manufactured,
the foil pack is impermeable to the propellant gas and to moisture
vapor and product to be dispensed, and as seen best in FIG. 5 it
comprises a laminate of heavy foil 32 and polyethylene film 33
enclosing a predetermined quantity of sorbent material (not shown,
but which can be granular or powdered or shaped as a cohesive body)
saturated or loaded with propellant gas and wetted with a non-polar
fluid. Just prior to being inserted into the container or while
being inserted the foil laminate is perforated with a plurality of
small holes 34 or slits (not shown).
[0037] FIG. 4 shows the pack prior to being perforated, but with
potential locations of holes shown in broken lines. The dispenser
comprises a domed top 35 crimped to the top end of the container, a
dispensing valve 13' carried by the domed top, and a dip tube 36
extending from the valve to the bottom of the container. The foil
pack containing the sorbent material saturated with propellant gas
and wetted with a non-polar fluid as previously described is placed
in the container prior to crimping the domed top in place. After
the domed top is crimped in place, propellant gas is charged into
the container to a desired pressure in accordance with conventional
methods, or in accordance with the process described in applicant's
copending application Ser. No. 11/805,995, the disclosure of which
is incorporated in full herein by reference. Following
pressurization of the container product is charged into the
container in accordance with conventional methods or in accordance
with the process described in applicant's copending application
Ser. No. 11/805,995. Functioning of the wetted sorbent material to
release stored gas is the same as in the previous embodiments.
[0038] FIG. 6 illustrates a fourth embodiment 40 in which
propellant gas, CO.sub.2, is placed in the container as a solid. In
this form of the invention one or more pieces of dry ice 41 are
dropped into the container 11''' prior to closing and sealing it,
followed by the adsorbent material 17, e.g. zeolite wetted with a
non-polar fluid. As the dry ice melts, gaseous CO.sub.2 is given
off, purging the container of air. The CO.sub.2 continues to come
off slowly as the dry ice melts, producing a low positive pressure
in the container. The valve 13 is then crimped and sealed on the
container, and product injected into the bag 14. Since not much
CO.sub.2 has been produced at this time there is very little back
pressure, enhancing the filling procedure. The dry ice continues to
melt, loading the zeolite and pressurizing the container. As
product is depleted during use the pressure is restored as in the
previous forms of the invention.
[0039] FIG. 7 illustrates a fifth embodiment 50 wherein the sorbent
(not shown) is sealed in a gas-permeable membrane 51 that permits
passage of the propellant gas but precludes passage of the product.
The sorbent can be in the form of a powder, granules, pellets, or
cohesive one-piece body, and can comprise any of the materials
described above. An advantage of this form of the invention is that
it can be placed directly in the product whether the product is a
polar fluid or a non-polar fluid, and can be loaded with propellant
gas either before or after being placed in the container.
[0040] Although particular embodiments of the invention are
illustrated and described in detail herein, it is to be understood
that various changes and modifications may be made to the invention
without departing from the spirit and intent of the invention as
defined by the scope of the appended claims.
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