U.S. patent number 3,888,998 [Application Number 05/302,149] was granted by the patent office on 1975-06-10 for beverage carbonation.
This patent grant is currently assigned to The Procter & Gamble Company. Invention is credited to Ronald Lee Sampson, David Denzil Whyte.
United States Patent |
3,888,998 |
Sampson , et al. |
June 10, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Beverage carbonation
Abstract
Beverage carbonation methods, compositions and devices employing
carbon dioxide-containing molecular sieves. Upon contact with
aqueous solutions carbon dioxide is released from such molecular
sieves and thereupon dissolves in the liquid to provide a
carbonated beverage.
Inventors: |
Sampson; Ronald Lee
(Cincinnati, OH), Whyte; David Denzil (Wyoming, OH) |
Assignee: |
The Procter & Gamble
Company (Cincinnati, OH)
|
Family
ID: |
26896162 |
Appl.
No.: |
05/302,149 |
Filed: |
October 30, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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200849 |
Nov 22, 1971 |
|
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Current U.S.
Class: |
426/67;
261/DIG.7; 261/121.1; 426/477; 426/561; 426/590; 426/591 |
Current CPC
Class: |
B65D
85/73 (20130101); A23L 2/40 (20130101); Y10S
261/07 (20130101) |
Current International
Class: |
A23L
2/40 (20060101); B65D 79/00 (20060101); A23l
001/00 () |
Field of
Search: |
;426/190,191,67,477,225,365,366 ;261/DIG.7 ;423/437,328 ;99/275
;252/455Z |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bashore; S. Leon
Assistant Examiner: Chin; Peter
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No.
200,849, filed Nov. 22, 1971 now abandoned.
Claims
What is claimed is:
1. A process for carbonating a potable aqueous solution comprising
contacting said solution with an effective amount of a porous
crystalline zeolite material, said zeolite having adsorbed therein
at least about 5% by weight of carbon dioxide, said contact taking
place at a temperature below about 110.degree.F and a pressure of
at least about 1 atmosphere.
2. A process in accordance with claim 1 wherein the crystalline
zeolite material is selected from the group consisting of Zeolite
X, Zeolite Y and Zeolite A and pore sizes of the crystalline
zeolite material range from about 3 Angstroms to about 10
Angstroms.
3. A process in accordance with Claim 2 wherein the pore sizes of
the crystalline zeolite material range from about 8 Angstroms to
about 10 Angstroms.
4. A process in accordance with claim 2 wherein the crystalline
zeolite material has an SiO.sub.2 /Al.sub.2 O.sub.3 mole ratio of
at least 3 and has at least 35% of the exchangeable metal ions
thereof removed or replaced with protons.
5. A process in accordance with claim 2 wherein the aqueous potable
liquid is contacted with from about 0.5 to about 4 grams of
crystalline zeolite material per fluid ounce of aqueous potable
liquid.
6. A process in accordance with claim 5 wherein the crystalline
zeolite material is in the form of spherical beads having a mesh
size of 8 .times. 12.
7. A process in accordance with claim 5 wherein the crystalline
zeolite material is in the form of spherical beads having a mesh
size of 4 .times. 8.
8. A process in accordance with claim 2 wherein from about 30% to
70% by weight of the crystalline zeolite material has pore sizes of
from about 3 Angstroms to about 5 Angstroms, the balance of said
crystalline zeolite material having pore sizes of from about 6
Angstroms to about 10 Angstroms.
9. A process in accordance with claim 2 wherein the crystalline
zeolite material is coated with a film of a non-toxic,
water-soluble compound.
10. A process in accordance with claim 1 wherein said porous
crystalline zeolite is supplemented with a chemical carbon dioxide
producing couple, said couple being present at levels sufficiently
low to avoid noticeable quantities of the salts thereof in said
beverage.
11. A process in accordance with claim 10 wherein said couple is
sufficient to produce only about 0.5 volume of dissolved carbon
dioxide.
12. A composition for making a flavorful carbonated beverage from
tap water or the like comprising a dry beverage mix and an amount
effective to carbonate the beverage of a porous crystalline zeolite
said porous crystalline zeolite material having adsorbed therein at
least about 5% by weight carbon dioxide.
13. The composition of claim 12 wherein the crystalline zeolite
material is selected from the group consisting of Zeolite X,
Zeolite Y and Zeolite A and pore sizes of the crystalline zeolite
material range from about 3 Angstroms to about 10 Angstroms.
14. The composition of claim 13 wherein said crystalline zeolite
material is in bead form and at least about 1/16 inch in its
smallest dimension.
15. The composition of claim 13 wherein the pore sizes of the
crystalline zeolite material range from about 8 Angstroms to about
10 Angstroms.
16. The composition of claim 15 wherein said crystalline zeolite
material is in bead form and at least about 1/16 inch in its
smallest dimension.
17. The composition of claim 13 wherein the crystalline zeolite
material has an SiO.sub.2 /Al.sub.2 O.sub.3 mole ratio of at least
3 and has at least 35% of the exchangeable metal ions thereof
removed or replaced with protons.
18. The composition of claim 17 wherein said crystalline zeolite
material is in bead form and at least about 1/16 inch in its
smallest dimension.
19. The composition of claim 12 wherein said crystalline zeolite
material is in the form of a molded disk.
20. The composition of claim 19 wherein said molded disk is held in
place in a drinking vessel.
Description
BACKGROUND OF THE INVENTION
This invention relates to methods, compositions and devices for the
carbonation of aqueous beverages at the point of consumption.
Carbonation is accomplished by contacting the beverage to be
carbonated with "molecular sieves," i.e., crystalline
aluminosilicates, which contain adsorbed gaseous carbon dioxide.
Carbon dioxide is released from such molecular sieves by
displacement with water from the beverage solution. The liberated
carbon dioxide is then dissolved by the liquid to form the
carbonated beverage.
Commercial beverage carbonation usually involves carbon
dioxide-liquid contact under pressure with intensive mixing in a
cooled container. Such commercial methods, of course, require
elaborate and sophisticated equipment not available in the home or
at the point of beverage consumption.
Several simple carbonation techniques which are suitable for home
use have been disclosed in the art. Most commonly, such prior art
carbonation systems utilize a chemical "couple" to generate carbon
dioxide in situ within the beverage to be carbonated. Such a couple
ususlly consists of the combination of an inorganic carbonate such
as sodium bicarbonate and an edible food acid such as citric acid
or an acid-acting ionic exchange resin. Contact between compounds
of this type in aqueous solution results in the formation of
gaseous carbon dioxide and a salt of the food acid. Several patents
(Mitchell, et al., U.S. Pat. No. 3,241,977, Mar. 22, 1966;
Mitchell, et al., U.S. Pat. No. 3,467,526, Sept. 16, 1969; Hovey,
U.S. Pat. No. 3,492,671, Jan. 27, 1970; and Hughes, U.S. Pat. No.
2,742,363, Apr. 17, 1956) describe preferred embodiments of such
acid-bicarbonate or acid resin-bicarbonate systems in detail. All
of these methods, however, result in formation of undesirable
off-tasting organic salts in solution or require utilization of
complex ion exhange material to prevent these salts from dissolving
in the beverage. Such salts are particularly noticeable and
objectionable to the consumer when formed in substantial amounts in
achieving relatively high levels of carbonation.
Another home carbonation technique utilizes dry beverage
compositions containing water-reactive carbonic acid anhydrides
which release CO.sub.2 or H.sub.2 CO.sub.3 in aqueous solution.
(Feldman, et al., U.S. Pat. No. 3,441,417, Apr. 29, 1969) These
compositions, however, require rather complex formulation and, in
many instances, require incorporation of a buffering system into
the beverage solution.
Accordingly, it is an object of the present invention to provide a
simple method for beverage carbonation which can be employed in the
home or at the point of consumption. It is a further object of the
instant invention to provide such a simple carbonation method which
does not result in undesirable build-up of off-tasting organic
salts in solution. It is a further object of the present invention
to provide such a beverage carbonation method which does not
necessitate formulation of complex dry carbonation compositions. It
is further object of the instant invention to provide simple but
effective devices for point-of-consumption beverage
carbonation.
It has now been discovered that by employing readily available
molecular sieves which contain adsorbed carbon dioxide and which
readily release such carbon dioxide upon contact with water, the
above-described objectives can be accomplished.
SUMMARY OF THE INVENTION
The instant invention provides methods, compositions and devices
for making carbonated beverages in the home. In general such
methods comprise contacting a beverage liquid with an effective
amount of a crystalline aluminosilicate molecular sieve material
having adsorbed therein at least about 5% by weight of carbon
dioxide. Such carbonation takes place at a temperature below about
110.degree.F and at a pressure at least about one atmosphere.
Compositions and devices particularly useful when effectuating such
molecular sieve carbonation are also provided.
DESCRIPTION OF THE DRAWINGS
Although the specification concludes with claims particularly
pointing out and distinctly claiming the subject matter forming the
present invention, it is believed that the same will be better
understood by reference to the following specification taken in
connection with the accompanying drawings in which:
FIG. 1 is a graph which demonstrates the effect of molecular sieve
pore size on carbonation of water. The horizontal axis represents
carbonation time in minutes. The vertical axis represents a
unitless measure of dissolved carbon dioxide expressed as the
volume of gaseous carbon dioxide (at 32.degree.F. and 1 atmosphere)
dissolved per volume of carbonated liquid (at 35.degree.F. and 1
atmosphere). The five curves are carbonation profiles at
35.degree.F and one atmosphere obtained from five different types
of molecular sieves which are presently available commercially from
the MOlecular Sieve Department of the Material Sciences Division
(formerly the Linde Division) of the Union Carbide Corporation.
FIG. 2 is a graph which demonstrates four-minute carbonation
performance factors as a function of molecular sieve pore size. The
horizontal axis represents molecular sieve pore size in Angstroms.
The vertical axis represents four-minute carbonation performance
factors, a performance factor being a unitless number defined
as:
[(Volume of CO.sub.2 dissolved after four minutes/(Volume of
CO.sub.2 dissolved at saturateion)] .times. [(Volume of CO.sub.2
dissolved after four minutes/(Volume of CO.sub.2 available within
the sieves used)]
The two curves represent 12 gram and 24 gram batches of molecular
sieves which were used to carbonate eight fluid ounces of water at
35.degree.F and one atmosphere.
FIG. 3 is a perspective view of a "teabag" type of beverage
carbonation device.
FIG. 4 is a perspective view of a "swizzle stick" or structured
teabag type of carbonation device.
FIG. 5 is a partial cutaway perspective view of a drinking vessel
which can be used to prepare a carbonated beverage.
FIG. 6 is a cutaway perspective view of another type of drinking
vessel which can be used to prepare a carbonated beverage.
FIG. 7 is an elevational view of a sealed flexible carbonation
chamber device which upon opening can be used to prepare a
carbonated beverage.
FIG. 8 is a vertical cross-sectional view of the sealed carbonation
chamber of FIG. 7.
FIG. 9 is a perspective view of the flexible carbonation chamber of
FIGS. 7 and 8 opened and ready for preparation of a carbonated
beverage.
FIG. 10 is an elevational view of a two compartmented bag
carbonation device of the present invention.
FIG. 11 is a perspective view of another carbonation device of the
present invention.
FIG. 12 is a vertical cross-sectional view of a collapsible
container/carbonation device of the present invention in the
collapsed form.
FIG. 13 is an elevational view of the container of FIG. 12 in the
in-use position.
DETAILED DESCRIPTION OF THE INVENTION
The instant invention utilizes carbon dioxide-containing molecular
sieves to effectuate carbonation of an aqueous potable solution.
The invention comprises a process for beverage carbonation in this
manner and compositions and devices for carrying out this
process.
Molecular sieves of the type used in this invention are crystalline
aluminosilicate materials of the following general formula:
M.sub.2/n O.SiO.sub.2.aAl.sub.2 O.sub.3.bH.sub.2 O
in the salt form, where n is the valence of a metal cation M, M
ordinarily is Na or K but may be other cations substituted by
exchange, a is the number of moles of alumina and b is the number
of moles of water of hydration.
Upon removal of at least some of the water of hydration by heating,
the crystalline aluminosilicates become highly porous and are
characterized by a series of surface cavities and internal pores
which form an interconnecting network of passageways within the
crystal. Such dehydrated molecular sieves are often referred to as
"activated" meaning that they are ready to adsorb carbon dioxide.
Due to the crystalline nature of such materials, the diameters of
the surface cavities and of the internal pores are substantially
constant and are of molecular magnitude. For this reason, the
crystalline aluminosilicates have found wide use in the separation
of materials according to molecular size or configuration, hence
the name molecular sieves.
Molecular sieves or crystalline aluminocilicates are also sometimes
referred to as crystalline zeolites and are of both natural and
synthetic origin. Natural crystalline aluminosilicates exhibiting
molecular sieve activity include for example, analcite, paulingite,
ptilolite, clinoptilolite, ferrierite, chabazite, gmelinite,
levynite, erionite and mordenite.
Since not all of the natural crystalline aluminosilicates are
available in abundance, considerable attention has been directed to
the production of synthetic equivalents. Two basic types of
crystalline aluminosilicate molecular sieves most readily available
on a commercial scle have been given the art-recognized
designations of "Zeolite X" and "Zeolite A." Other molecular sieves
which have been synthesized include Zeolites B, F, G, H, K-G, J, L,
M, K-M, Q, R, S, T, U, Y, and Z.
Zeolite X is described, together with a process for making it, in
detail in U.S. Pat. No. 2,882,244, incorporated herein by
reference. The general formula for Zeolite X, expressed in terms of
mole fractions of oxides, is as follows:
0.9 .+-. 0.2M.sub.2/n O:Al.sub.2 O.sub.3 :2.5 .+-. 0.5SiO.sub.2 :0
to 8 H.sub.3 O
In the formula "M" represents a metal and n its valence. As noted,
the zeolite is activated or made capable of adsorbing certain
molecules by the removal of water from the crystal as by heating.
Thus the actual number of moles of water present in the crystal
will depend upon the degree of dehydration or activation of the
crystal.
The metal represented in the formula above by the letter M can be
changed by conventional ion exchange techniques. The sodium form of
the zeolite X, designated sodium Zeolte X, or simply as a NaX
molecular sieve, is the most convenient to manufacture. For this
reason the other forms of Zeolite X are usually obtained by the
modification of sodium Zeolite X.
A typical formula for sodium Zeolite X is
0.9Na.sub.2 O:Al.sub.2 O.sub.3 :2.5 SiO.sub.2 :6.1 H.sub.2 O
After activation by heating, at least some of the water is removed
from the sodium Zeolite X or other molecular sieve material and it
is then ready for use in the instant invention.
The major lines in the X-ray diffraction pattern of sodium Zeolite
X are set forth in Table A below.
TABLE A ______________________________________ d Value of
Reflection in A. 100 I/I.sub.o
______________________________________ 14.42 .+-. 0.2 100 8.82 .+-.
0.1 18 4.41 .+-. 0.05 9 3.80 .+-. 0.05 21 3.33 .+-. 0.05 18 2.88
.+-. 0.05 19 2.79 .+-. 0.05 8 2.66 .+-. 0.05 8
______________________________________
In obtaining the X-ray diffraction powder patterns, standard
techniques are employed. The radiation is the K doublet of copper,
and a Geiger counter spectrometer with a strip chart pen recorder
is used. The peak heights, I, and the positions as a function of
2.theta. where .theta. is the Bragg angle, are read from the
spectrometer chart. From these, d (obs.), the interplanar spaacing
in A., corresponding to the recorded lines is calculated. The X-ray
patterns indicate a cubic unit cell of dimensions between 24.5 A.
and 25.5 A.
To make sodium Zeolite X reactants are mxied in aqueous solution
and held at about 100.degree.C. until the crystals of Zeolite X are
formed. Preferably the reactants should be such that in the
solution the following ratios by weight prevail:
SiO.sub.2 /Al.sub.2 O.sub.3 3 - 5 Na.sub.2 O/SiO.sub.2 1.2 - 1.5
H.sub.2 O/Na.sub.2 O 35 - 60
The manner in which Zeolite X can be obtained is illustrated by the
following: 10 grams of NaAlO.sub.2, 32 grams of an aqueous solution
containing by weight about 20% Na.sub.2 O and 32% SiO.sub.2, 5.5
grams of NaOH and 135 cubic centimeters of H.sub.2 O are mixed and
held in an autoclave for 47 hours at about 100.degree.C.
Crystalline sodium Zeolte X is recovered by filtering the reacted
materials and washed with water until the pH of the effluent wash
water is between 9 and 12. The crystals are then at least partially
dried after which they are ready for use in the instant
invention.
Zeolite A is described in detail together with processes for its
preparation in U.S. Pat. No. 2,882,243, incorporated herein by
reference. The general formula for Zeolite A, expressed in terms of
mole fractions of oxides is as follows:
1.0.+-.0.2 M.sub.2/n O:Al.sub.2 O.sub.3 :1.85.+-. 0.5SiO.sub.2 :0
to 6 H.sub.2 O
In the formula M represents a metal, hydrogen, or ammonium, N the
valence of M. The amount of H.sub.2 O present in Zeolite A will of
course depend on the degree of dehydration of the crystals.
As in the case of Zeolite X and other zeolites, the element or
group designated by M in the formula can be changed by conventional
ion exchange techniques. Sodium Zeolite A is the most convenient
form to prepare, and other forms are usually obtained from it by an
exchange of ions in aqueous solutions. A typical formula for sodium
Zeolite A is
0.99 Na.sub.2 O:1.0 Al.sub.2 O.sub.3 :1.85 SiO.sub.2 :5.1 H.sub.2
O
The removal of at least part of the water, as by heating, would be
sufficient to prepare the sodium Zeolite A for use in the instant
invention.
Using the techniques by which the X-ray diffraction data for Sodium
Zeolite X was obtained, similar data for sodium Zeolite A is
obtained and is recorded in Table B.
TABLE B ______________________________________ d Value of
Reflection in A. 100 I/I.sub.o
______________________________________ 12.2 .+-. 0.2 100 8.6 .+-.
0.2 69 7.05 .+-. 0.15 35 4.07 .+-. 0.08 36 3.68 .+-. 0.07 53 3.38
.+-. 0.06 16 3.26 .+-. 0.05 47 3.96 .+-. 0.05 55 2.73 .+-. 0.05 12
2.60 .+-. 0.05 22 ______________________________________
To make sodium Zeolite A reactants are mixed in aqueous solution
and held at about 100.degree.C. until crystals of sodium Zeolite A
are formed. The reactants should be such that in the solution the
following ratios prevail:
SiO.sub.2 /Al.sub.2 O.sub.3 1.2 - 2.5 Na.sub.2 O/SiO.sub.2 0.8 -
3.0 H.sub.2 O/Na.sub.2 O 35 - 200
An example of the manner in which sodium Zeolite A may be prepared
is as follows: 80 grams of NaAlO.sub.2, 126 grams of an aqueous
solution of sodium silicate containing about 7.5% by weight
Na.sub.2 O and 25.8% by weight SiO.sub.2, and 320 cubic centimeters
of H.sub.2 O are placed in an autoclave. In the autoclave the
following ratios prevail: SiO.sub.2 /Al.sub.2 O.sub.3, 1.2;
Na.sub.2 O/SiO.sub.2, 1.2; and H.sub.2 O/Na.sub.2, 36. The contents
of the autoclave are held at about 100.degree.C. for about 12
hours. Crystalline sodium Zeolite A is recovered by filtration and
washed with distilled water until the effluent wash water has a pH
of between 9 and 12. After drying and at least partial dehydration
the crystals are ready for use in the instant invention.
These and other types of crystalline aluminosilicate molecular
sieves useful in the instant invention are described more fully in
the following publications incorporated herein by reference: Hersh,
Molecular Sieves, Reinhold Publishing Corporation, 1961; Thomas and
Mays, "Separations with Molecular Sieves" found at pages 45-97 of
Physical Methods in Chemical Analysis, Volume IV, edited by Walter
G. Berl, Academic Press, 1961; Breck, "Crystalline Molecular
Sieves," found at page 678 of the Journal of Chemical Education,
Volume 41, December, 1964; and "Linde Molecular Sieves" a technical
publication of the Union Carbide Corporation.
Several specific types of molecular sieves are particularly useful
for employment in the instant beverage carbonation process and
devices. (In the following description references to molecular
sieves by "Types" all refer to materials presently available from
the Molecular Sieve Department of Union Carbide. Generic
designations such as NaA, NaX, CaA, CaX refer respectively to
sodium Zeolite A, sodium Zeolite X, calcium Zeolite A, calcium
Zeolite X, etc.) These include Type 4A and 13X molecular sieves.
Type 4A (NaA) has a four Angstrom pore size and can be
characterized by the chemical formula
Na.sub.12 [(AlO.sub.2).sub.12 (SiO.sub.2).sub.106 ].27 H.sub.2
O.
Type 13X (NaX) has a ten Angstrom pore size and can be
characterized by the chemical formula
Na.sub.86 [AlO.sub.2).sub.86 (SiO.sub.2).sub.106 .276H.sub.2 0.
With both the Type 4A and 13X molecular sieves, the sodium ions can
be exchanged with other cations, such as potassium and calcium, to
provide varying pore sizes and somewhat different adsorption
characteristics. For example, the Type 4A molecular sieve having
approximately 70% of its sodium cations exchanged for calcium
cations yields a molecular sieve marketed commercially by the Union
Carbide Corportion as Type 5A (CaA) having a five Angstrom pore
size. Likewise, the Type 13X (NaX) molecular sieve having about 70%
of its sodium cations exchanged for calcium cations is marketed
commercially by the Union Carbide Corporation as the Type 10X (CaX)
having an eight Angstrom pore size. Another molecular sieve, the
type 3A has a potassium Zeolite A (KA) structure and a three
Angstrom pore size.
It is also possible to commercially obtain crystallization
aluminosilicate molecular sieves which are classified as
"acid-resistant." Acid-resistant molecular sieves are crystalline
zeolites which do not structurally degrade and from which metal
ions are not leached upon prolonged contact with low pH solutions.
Such acid-resistant molecular sieves are usually prepared by
removing or replacing with protons many of the exchangeable metal
ions found in natural and synthetic molecular sieves. This is
accomplished by first exchanging metal ions with ammonium ions and
subsequently heating the resulting ammonium form of such molecular
sieves to about 400.degree.C. to decompose the ammonium cations.
Although the exchangeable metal ions in all crystalline memtal
aluminosilicates can be removed or replaced to some extent by this
procedure, in most cases complete ion exchange of this type
destroys the crystal structure of the zeolite. In order to replace
more than 35% of the zeolite metal ions without destroying the
aluminosilicate crystal, those zeolites having a siO.sub.2
/Al.sub.2 O.sub.3 molar ratio greater than 3:1 are employed in the
above-described ion exchange processes. Zeolites having such a high
SiO.sub.2 /Al.sub.2 O.sub.3 mole ratio include the natural mineral
faujasite and the synthetic sodium "Zeolite Y" (NaY) described more
described more fully in U.S. Pat. No. 3,130,007, incorporated
herein by reference. Zeolite Y has the general formula (0.9.+-.0.2)
Na.sub.2 O.Al.sub.2 O.sub.3.cSiO.sub.2.dH.sub.2 O wherein c varies
from 3 to 6 and d (before dehydration) is less than or equal to 9.
The process for lowering the metal ion content of crystalline metal
aluminosilicates is described more fully in U.S. Pat. No. 3,130,006
and 3,460,904 incorporated herein by reference.
Examples of commercially available acid-resistant molecular sieves
produced by the metal ion removal process described above include
the Type AW-300 molecular sieve which has a four Angstrom pore
size, the Type AW-500 molecular sieve which has a five Angstrom
pore size, the Type SK40 (NaY in particulate form with a clay
binder) and Type Sk41 (NaY in particulate form) molecular sieves
both having a pore size of 8-10 Angstroms and the Zeolon Series
100, 200 and 900, presently marketed by the Norton Company.
Various molecular sieve forms ranging from powder (0.5 - 12
microns) to 1/4 inch spheres are commercially available, with most
of the non-powdered forms incorporating a binder of inert clay at a
20% by weight level. Common sieve forms include extruded 1/16 and
1/8 with diameter pellets and 4 .times. 8 and 8 .times. 12 mesh
beads, i.e., spheres which will pass through an 8 mesh screen but
not through a 12 mesh screen. Molecular sieves may be placed in
other molded forms of any size or shape desired with binders of
clay or polymeric resins.
For purposes of the instant invention, the material adsorbed within
such molecular sieves is, of course, gaseous carbon dioxide. Carbon
dioxide is strongly adsorbed on such sieves, but is readily
displaced by the stronger and preferably adsorption of water. Hence
the release of adsorbed carbon dioxide from molecular sieves in
aqueous solution provides basis for the carbonation technique of
the instant invention.
Molecular sieves are "loaded" with carbon dioxide merely by
contacting the activated (i.e., at least partially dehydrated)
sieve material with gaseous carbon dioxide under anhydrous
conditions to bring about carbon dioxide adsorption. Typically, the
sieve materials can be dehydated to about 2% by weight water.
Preferably, molecular sieves are charged with carbon dioxide in a
packed bed column to which the gas is passed in ambient temperature
and at a slight positive pressure (up to 0.5 psig). For use in the
instant beverage carbonation process and devices, molecular sieves
should be loaded to the extent of at least about 5% by weight
(i.e., weight of carbon dioxide adsorbed/weight of loaded sieves
.times. 100%). The extent to which a particular size of sieves,
i.e., sieves with a given pore size, adsorb carbon dioxide at any
particular temperature or pressure is easily determined by
experimentation or by utilization of adsorption data provided for
commercially available sieves.
It is important that the carbon dioxide-loaded molecular sieves be
packaged and stored in a manner which will prevent contct with
atmospheric moisture prior to use in the present invention. Such
atmospheric moisture would displace carbon dioxide rendering the
sieves ineffective for beverage carbonation.
The carbon dioxide-loaded molecular sieves are contacted with
aqueous potable liquid to effectuate the carbonation process for
the instant invention. Carbon dioxide is released from the sieves
by the preferential adsorption of water from the beverage solution.
A carbonated beverage results when this released carbon dioxide is
dissolved in the aqueous liquid. Subsequent release of this
dissolved carbon dioxide in the mouth upon drinking provides the
characteristic feel and taste of a carbonate beverage. Of course,
the extent of carbonation increases as more carbon dioxide is
dissolved. Carbonation is usually measured in a unit, hereinafter
referred to as "volumes of dissolved CO.sub.2 " or "volumes of
carbonation" defined as the volume of gas (reduced to standard
conditions, i.e., 760 mmHg and 32.degree.F.) which at the
temperature and pressure of carbonation is dissolved in a given
volume of beverage.
For purposes of evaluating various molecular sieve carbonation
systens, another carbonation indicator known as a performance
factor, P.sub.n, can be defined and expressed as the following
formula:
P.sub.n = (A.sub.n) (B.sub.n)
wherein A.sub.n is an effectiveness factor defined as the ratio
(Volume of CO.sub.2 dissolved at n carbonation minutes/Volume of
dissolved CO.sub.2 at saturation)
and B.sub.n is an efficiency factor, defined as the ratio
(Volume of CO.sub.2 dissolved at n carbonation minutes/Total volume
of CO.sub.2 available within the sieve used)
The performance factor combines the fraction of saturation obtained
(effectiveness) with the efficiency of carbonation for a given time
period. In the most ideal case, A.sub.n would be unity if a
saturated solution were generated and greater than unity if
supersaturation resulted. B.sub.n would be unity if all the carbon
dioxide present goes into solution. Therefore, the larger the
performance factor, the more preferred a given molecular sieve
carbonation system is. This performance factor is used to identify
and evaluate essential sieve parameters and beverage solution
characteristics of the instant invention.
The solubility of carbon dioxide in aqueous solution is strongly a
function of temperature and pressure. Solubility data under various
temperature and pressure conditions can easily be determined from
prior art literature. Thus, certain temperature and pressure
limitations apply to the carbonation process of the instant
invention. The solubility of carbon dioxide in pure water
approaches 0.5 volumes of dissolved CO.sub.2 (a weakly carbonated
beverage) at approximately 110.degree.F. and one atmosphere.
Accordingly, carbonation temperatures above 110.degree.F. are not
desirable in the practice of the present invention. There is no
theoretical lower temperature limit for the instant carbonation
process, but there is, of course, the practical lower limit of the
freezing point of the particular aqueous beverage solution being
carbonated. A highly preferred carbonation temperature is that of
an ice-containing beverage mixture, i.e., approximately
32.degree.F.
Likewise, beverage carbonation with molecular sieves becomes
unacceptably inefficient at carbonation pressures below one
atmosphere. Carbonation pressures above one atmosphere enhance
carbon dioxide solubility and render molecular sieve beverage
carbonation especially effective. In one of its aspects, therefore,
the present process encompasses carbonation in closed vessels
wherein pressures of up to about 10 atmospheres are developed. From
the practical standpoint of in-home or point-of-consumption
carbonation, however, atmospheric pressure, i.e., open container
carbonation, is preferred in many instances.
Carbonation time is important in many applications but is not a
critical variable in the instant carbonation process. Tine of
contact of the loaded molecular sieves with beverage liquid will
naturally vary with the amount of aqueous solution present; the
nature of that solution; the amount, type, and level of charge of
the molecular sieves employed; and the "strength" of carbonated
beverage desired. By employing molecular sieves loaded with carbon
dioxide to the extent of at least 5% by weight and by carbonating
at temperature and pressure conditions of the present invention,
suitably carbonated beverages can be obtained after typical in-home
carbonation times (2-15 minutes). Carbonation system providing
carbon dioxide release for longer or shorter times than typical can
be achieved by utilizing preferred embodiments of the instant
invention described hereinafter.
Varying the pore size of the molecular sieves empoloyed in the
instant process affects both the carbonation rate and final
carbonation level. This is demonstrated by the typical data shown
in FIG. 1 of the drawings. Performance factors at a typical
carbonation time (four minutes) generally increase with increasing
pore size as illustrated by FIG. 2 of the drawings. The curves of
FIGS. 1 and 2 are representative of data obtained from actual sieve
tests wherein data were gathered from carbonating eight ounces of
cool water at atmospheric pressure with varying weights of 3, 4, 5,
8 and 10 Angstrom pore sized molecular sieves Types 3A, 4A, 5A, 10X
and 13X, respectively. Each type of sieve was loaded with carbon
dioxide to the maximum extent practical utilizing as received
activated sieves; viz., 7.9%, 10.8%, 11.7%, 10.9% and 13.2% by
weight respectively. As can be seen the larger sieve types,
particularly those of 8-10 Angstom pore size exhibit higher four
minute performance (P.sub.4) and consequently are preferred.
As might be expected, increasing the quantity of molecular sieves
employed for a given amount of beverage solution increases the
quantity of carbon dioxide released, even though carbonation
efficiency decreases markedly with an increase in the total amount
of molecular sieves present. Although the optimum amount of
molecular sieves employed varies with the characteristics of the
sieves utilized and the beverage solution to be carbonated, the
preferred quantity of molecular sieves ranges from about 0.5 to
about 4 grams (before loading) of molecular sieves per fluid ounce
of beverage to be carbonated.
The physical shape or form of the molecular sieves employed can
also affect beverage carbonation. Powdered molecular sieves are
preferably employed in the instant process by molding such sieves
into any suitable form which provides a large ratio of surface area
to volume. This may be done by employing porous binder systems to
mold or extrude the sieves into such shapes as pellets, spheres or
thin disks. Processes for bonding or molding molecular sieves into
various forms are well known in the art and are disclosed, for
example, in U.S. Pat. Nos. 3,158,597, 3,213,l64, British Pat. No.
994,908 and Belgian Pat. No. 627,185, all of which are herewith
incorporated by reference.
Mixtures of molecular sieves can be employed to obtain particular
carbonation characteristics desired. In general, molecular sieve
types having smaller pore sizes (3-5 Angstroms and particularly 3-4
Angstroms) release carbon dioxide upon contact with water more
slowly but continue to release it for a longer period of time.
Molecular sieves having larger pore openings (greater than 6
Angstroms) provide relatively high initial release rates of carbon
dioxide, but such release is not sustained over longer periods of
time. The ability of an aqueous solution to dissolve carbon dioxide
is inversely related to the degree of saturation thereof. During
initial carbonation carbon dioxide can be dissolved at a
comparatively high rate while lower rates prevail as the solution
approaches saturation. Accordingly, systems wherein both high
initial carbon dioxide release and sustained carbon dioxide
dissolution are desired can be realized by employing mixtures of
sieves having varying pore sizes. A preferred sustained-release
carbonation process employs a mixture of molecular sieves wherein
from 30% to 70% by weight of the sieve mixture consists of sieves
having pore sizes from 3 to 5 Angstroms, and preferably 3 to 4
Angstroms, with the balance of the molecular sieves employed having
pore sizes from about 6 to 10 Angstroms.
In some applications it may be desirable to use a mixed molecular
sieve/chemical couple system. Chemical couples are generally less
expensive per volume of released carbon dioxide than are molecular
sieves. The off-flavor of the salts from carbon dioxide releasing
chemical couples are barely noticeable, if at all, in low levels
(which vary with the chemicals in the couple, the flavorings in the
beverage and the acuity of the consumer). Typically, about 0.5 to
0.75 volumes of dissolved carbon dioxide (a weakly carbonated
beverage) can be achieved in a carbonated cola beverage via a
chemical couple without achieving undesirably high levels of (i.e.,
noticeable off-flavors due to) salts. Consequently a desirable way
to achieve carbonation is with a low level of chemical couple
carbonation supplemented by molecular sieve carbonation. In such a
mixed system, the molecular sieves will preferably be of the
smaller pore size variety (i.e., about 3 to 5 Angstroms for slow
release) to complement the fast release chemical couple.
The type of beverage solution to be carbonated by the process of
the instant invention is not critical. The beverag liquid must, of
course, be aqueous in nature. Such liquids can contain in addition
to water, any type of non-interfering flavorant, coloring agent,
food additive, medicine, or alcohol. Such materials can
alternatively be premixed with carbon dioxide loaded molecular
sieves forming compositions which can be used to form flavorful
carbonated beverages from tap water. In still another variation,
flavorings and colorings can be provided in an aqueous mixture
which is added to water along with the carbon dioxide loaded
sieves. Examples of the types of beverage which can be made from
suitable liquids by carbonation with the present invention include
soft drinks, medicinal preparations, beer and sparkling wine.
Certain solutes which might be present in beverage solutions can,
however, affect carbon dioxide dissolution, and certain preferred
embodiments of the instant invention are particularly useful when
such solutes are involved. Although artificial sweeteners such as
saccharin and saccharin-containing compositions appear to have
little effect on molecular sieve beverage carbonation, various
natural sweeteners retard the rate and extent of carbonation from
molecular sieves. For example, fructose, sucrose and glucose at
levels of typical soft drink beverages noticeably inhibit
carbonation of beverages containing them. It has been surprisingly
discovered, however, that for carbonation of solutions containing
fructose or glucose, 10 Angstrom molecular sieves in the form of 4
.times. 8 mesh beads provide much better carbonation rate results
than with comparable solutions containing sucrose.
The presence of the common food acid components, such as citric
acid, up to the level of about 1% appears to have very little
effect on the rate or extent of beverage carbonation by molecular
sieve techniques. Such food acid-containing drinks, however,
necessarily are rather low pH solutions (a 1% aqueous citric acid
solution, for example, has a pH of 2). Prolonged contact of such
solutions with many synthetic molecular sieve materials will result
in gradual leaching of metal ions from the sieve material. As a
result the pH of such beverages may rise to the extent that
noticeable flavor changes occur. Accordingly when food
acid-containing beverage liquids are being carbonated in accordance
with the process of the instant invention, it is preferred to
utilize acid-resistant molecular sieves described above, i.e.,
crystalline metal aluminosilicates having an SiO.sub.2 /Al.sub.2
O.sub.3 molar ratio of at least 3 which have had at least 35% of
the exchangeable metal ions removed or replaced with protons.
When carbon dioxide is released quickly in the solution from
molecular sieves, it is not generally as efficiently dissolved as
when release rates are slower. Slower release rates in general
provide better opportunity for gas-liquid contact and therefore
promote carbon dioxide dissolution. Dissolution can thus generally
be enhanced by utilizing some means for controlling the rate of
carbon dioxide release from the molecular sieve material. As noted
above, one method of reducing the rate of carbon dioxide
displacement by water from molecular sieves resides in employing at
least some molecular sieves having pore sizes of from 3 to 5
Angstroms. Another means for controlling and retarding carbon
dioxide release rate from molecular sieves comprises coating such
sieves with a water-soluble material that impedes water entry into
the carbon dioxide-containing molecular sieve channels as the
coating is being dissolved. Any non-toxic, water-soluble coating
compound such as polyvinyl alcohol, polyvinyl pyrrolidone, or
hydroxypropyl cellulose is suitable. Readily available
hydroxypropyl cellulose is the preferred coating.
As noted, carbon dioxide release rate can also be controlled by
employing different forms of molecular sieves. Variation in the
volume to surface ratio of the aluminosilicate material has a
marked effect on carbon dioxide displacement from the molecular
sieves. In general sieves having a higher volume to surface area
release carbon dioxide more slowly and over a longer time period
than sieves having a lower volume to surface ratio.
Carbonation in accordance with the instant invention can, of
course, be accomplished by any method of contacting molecular
sieves with the beverage liquid. Generally, loaded molecular sieves
are placed in a container, and the liquid to be carbonated is then
added in sufficient amount to cover the sieves. Unless very fine,
impalpable, non-toxic, consumable molecular sieve powder is
utilized, carbonation in this manner necessitates separation of the
molecular sieve material from the beverage liquid before
consumption. This can be done, for example, by filtration,
straining, decanting of the beverage or withdrawal of the sieve
material from the carbonation vessel. In order to eliminate the
need for filtration or straining, several beverage carbonation
devices for employing the molecular sieve carbonation process of
the instant invention are provided. Each of the devices described
can be used with carbon dioxide loaded sieves alone (with a
pre-flavored beverage) or in combination with various flavorings
and additives (with tap water or the like).
The simplest device for employing the molecular sieve beverage
carbonation process of the instant invention comprises a water and
gas permeable container in which molecular sieves and, if desired,
dry beverage mix, can be enclosed. An overwrap of material
substantially impervious to water and water vapor is used to
protect this and the other devices illustrated and described except
the embodiments of FIGS. 5-7, 10 and other embodiments which are
effectively sealed prior to use. The container is removed from its
overwrap and submerged in the beverage to be carbonated with the
container preventing the molecular sieve material from being
dispersed in the beverage.
Preferably such containers are in the form of a flexible net of
inert material, such as cloth, nylon, paper, polyester, fiberglass
or any other water-insoluble synthetic polymeric material, having
mesh openings large enough to permit substantially unimpeded escape
of carbon dioxide bubbles and small enough to retain the molecular
sieves (in whatever form utilized) inside the netting. Thus if 4
.times. 8 beads are employed, netting having a mesh size (number of
openings per linear inch) greater than 8 must be utilized. Likewise
for 8 .times. 12 beads, netting larger than 12 mesh must be
employed. One satisfactory material for this application is the
open mesh polymeric netting presently available from Hercules,
Inc., under the trademark Delnet.
An example of such a container is shown by FIG. 3 in the drawing.
Carbon dioxide-loaded molecular sieves, 1, are enclosed in an open
mesh netting, 2, which has been closed by heat-sealing the seams,
3. If desired, colorings and flavorings in dry bead form can also
be disposed within such a water and gas permeable container.
Another device for carbonating beverages in accordance with the
instant invention comprises a water and gas permeable container of
the type described above affixed to a frame and handle assembly so
that movement of the molecular sieve-containing, gas-permeable
container can be controlled below the surface of the liquid being
carbonated. This structured container can then be used to agitate
the beverage solution during carbonation, thereby enhancing
dissolution of released carbon dioxide. An example of this type of
structured "swizzle stick" is shown by FIG. 4 in the drawing. Open
mesh netting, 10, encloses a triangular frame, 11, and contains
carbon dioxide-loaded molecular sieves, 12. The netting is sealed
by a ring, 13, at the juncture between the triangular frame the
stirring handle, 14. Again beads of dry colorings and flavorings
can be mixed with the molecular sieves, allowing the formation of a
flavorful carbonated beverage from tap water.
Carbonation devices can also be constructed having molecular sieve
material comprising an element of a beverage container itself. For
example, standard drinking vessels can be employed for this purpose
by affixing to the inside surfaces thereof, powdered, pelleted or
beaded molecular sieves. Generally, the sieves are dispersed over
such area of the inside surfaces as will be contacted by the liquid
beverage when the container is filled. By distributing molecular
sieves in this manner, carbon dioxide is released into solution in
many different places. Carbon dioxide bubbles thus travel through a
large volume of liquid, thereby greatly enhancing dissolution in
the beverage.
Attachment of sieves can be accomplished by employing any inert
insoluble adhesive, such as paraffin or epoxy resins. If the
drinking vessel is plastic in nature, sieves can be adhered to the
heat-softened inside surfaces of the vessel, to be affixed in place
upon cooling. Such drinking vessels can also contain dry beverage
mix flavorings and colorings in addition to molecular sieve
material, allowing the creation of flavorful carbonated beverages
from tap water.
An example of this type of beverage carbonation device is
illustrated by FIG. 5 in the drawing. Beads of molecular sieve
material, 20 are adhered or anchored to the inside surface, 21, of
a drinking cup or container, 22.
Molecular sieves can also be affixed directly to drinking vessels
by first molding the sieve material into solid forms which fit the
contour of the vessels and which, when affixed to the inside of the
vessels, present their surface area to be covered and contacted by
the beverage liquid. Manufacture of such molded sieve forms using
inert binders of clay or polymeric resins is known in the art as
discussed above. The forms themselves may be attached to the inside
surfaces of the drinking vessel by utilizing any inert insoluble
adhesive material or by employing as vessels, containers which by
their form or shape retain such molded sieve forms in place beneath
the surface of the contained beverage. By varying the thickness of
the sieve forms between about 0.001 and 3 inches, containers can be
manufactured which provide various carbonation rates when filled
with liquid. Again, the drinking vessel can also contain dry
beverage mix.
An example of this type of carbonation device is shown by FIG. 6 in
the drawing. A bonded disc of molecular sieve powder, 30, is placed
at the bottom of a flexible drinking container, 31, and held in
place by an insoluble adhesive or simply by pressing the disc into
the bottom of the conical flexible cup.
Another type of molecular sieve carbonation device comprises an
open top carbonation chamber filled with loaded molecular sieves. A
screening means is affixed within the carbonation chamber to
prevent escape therefrom of the solid molecular sieve particles.
Beverage liquid is placed into the carbonation chamber, resulting
in carbonation thereof upon contact with the loaded molecular
sieves within the chamber. After carbonation is complete, the
beverage is consumed or poured from the chamber. The screening
means prevents molecular sieve particles and, in some cases, foam
from being consumed or decanted with the beverage.
The carbonation chamber can be rigid or flexible and made from any
inert, water-insoluble material. If a flexible chamber is employed,
support means for holding the chamber during carbonation can also
be employed. The chamber can also be sealable for storage and
shipping.
The screening means can be constructed of any inert,
water-insoluble material. As before, the mesh of the screen can be
of any size which will readily pass liquid through but which will
block passage of the insoluble molecular sieve particles employed.
The screening means can be affixed in the carbonation chamber in
any desired position or location. For example the screening means
can be used to retain molecular sieve material at the bottom of a
drinking vessel or can be placed across the top or mouth of the
carbonation chamber.
The carbonation chamber device can contain in addition to carbon
dioxide-loaded molecular sieve material a dry beverage mix. If such
a beverage mix is employed, only water need be added to the
carbonation chamber to produce the flavored, carbonated
beverage.
An example of a flexible, sealable carbonation chamber assembly is
shown by FIGS. 7, 8 and 9 in the drawing. A flexible watertight
bag, 40, is filled with carbon-dioxide containing molecular sieves,
41, and dry beverage mix, 42. A flexible screen or net, 43, in the
form of a circle is affixed with a heat-sealed seam, 44, across the
opening of the bag near the top. The edges of the bag above the
flexible screen are heat-sealed in another seam, 45, to render the
bag air- and water-tight for storage. In order to use the
carbonation device, the top edge of the closed bag including the
heat-sealed seam, 45, is torn off and the bag opened as shown in
FIG. 9. The bag is then positioned inside the handled container,
46, with the top edges of the bag being folded over the lip of the
handled container. Water is poured through the netting opening of
the bag to prepare the carbonated beverage. The beverage can then
be poured from the bag and container with the netting acting to
screen the spent molecular sieve particles and foam as the beverage
is decanted.
FIG. 10 is an elevational view of a package, 50, which can be used
in various ways in conjunction with the instant invention. The
package will typically be constructed of any suitable flexible
water and water vapor impervious material, 51, such as
polyethylene, polypropylene or the like which is heat sealed at the
top in the region, 52, and at the bottom in the region, 53. A
medial transverse seal, 54, divides the package into compartments,
55 and 56. In one application, the package, 50, can contain carbon
dioxide loaded molecular sieves in one compartment and a beverage
concentrate including flavorings and colorings in the other
compartment. Preferably the beverage concentrate will be in liquid
form due to the ease with which this form mixes with water. In this
application, both compartments of the package, 50, are opened and
the contents are placed in a container with a suitable amount of
water. The carbonation process, i.e., the generation and migration
of bubbles of carbon dioxide provides sufficient agitation to
thoroughly mix the resultant beverage when a liquid beverage mix is
used. Separation of the spent molecular sieves from the beverage
being consumed is effected in any of the aforementioned ways.
In another application, the package, 50, is provided with a medial
seal which can be peeled or otherwise opened to place the two
compartments 55 and 56 in communication without destroying the
integrity of the material, 51. Known techniques are available for
forming such a weak seal. In this execution one compartment
contains a fully diluted (i.e., at the correct strength for
drinking) uncarbonated beverage. The other compartment contains
carbon dioxide loaded sieves. (Alternatively the beverage
flavorings and colorings can be included in dry form with the
molecular sieves.) In either event, opening the medial seam, 54,
allows contact between the loaded sieves and water and the
consequent carbonation of the beverage. Again a water and gas
pervious bag or the like can and preferably will be used to retain
the spent sieves. With a suitably designed package, 50, pressure
carbonation up to about two atmospheres pressure, with the
associated higher levels of dissolved carbon dioxide can be
achieved. Also, the convenience of a light weight flexible easily
storable container can be made available to the carbonated beverage
market without the flavor disadvantages of pure chemical couple
systems. Pre-carbonated beverages, as opposed to point-of-use
carbonated beverages cannot be provided in simple flexible
packages, of course, due to the tendency of such pre-carbonated
beverages to become "flat" as the carbon dioxide diffuses through
the package walls.
FIG. 11 is a perspective view of an alternate carbonating device,
60, in which a disc, 61, of carbon dioxide loaded molecular sieve
material with suitable binder, preferably insoluble, is adhered to
or molded around support member, 62, which can be a rod-like
member, making the device, 60, an alternate to the swizzle-stick of
FIG. 4. Alternatively, the support member can be a flexible member
such as a string, allowing the disc, 61, to be placed in the
beverage to be carbonated much as a teabag is placed in a cup of
tea. With either of these variations, the disc, 61, can also
include dry flavorings and colorings as coatings thereon to allow
formation of a flavorful carbonated beverage from water.
FIG. 12 is a vertical cross section of another carbonation device
of the present invention. The container, 70, is of plastic material
and includes a plurality of circumferential pleats, 71, which allow
vertical expansion of said container to the in-use configuration
shown in FIG. 13. Such a container, 70, encloses a suitable
quantity of carbon dioxide loaded molecular sieves, 72, which are
preferably in the bead or pellet form and, optionally, coloring and
flavoring ingredients. For shipment and storage the container, 70,
is held in the collapsed form of FIG. 12 by any suitable means such
as a plastic shrink-film overwrap.
When it is desired to prepare a carbonated beverage the shrink-film
is removed. The pouring spout, 73, is then disengaged from the
neck, 74, of the container, 70, (typically a threaded engagement)
and removed therefrom along with the overcap, 75. A piece of the
aforementioned Delnet material, 76, or any other means for
retaining the molecular sieves within the container, 70, covers the
inlet to the pouring spout, 73, and preferably is attached
thereto.
The liquid to be carbonated (and optionally flavored and colored)
is then placed within the container, 70, along with ice if desired.
The pressure of the contained beverage forces the pleats, 71, to
unfold and the container, 70, to expand to the configuration shown
in FIG. 13. The pourspout, 73, overcap, 75, and Delnet material,
76, are then reconnected to the neck, 74, of the container, 70.
When the carbonated beverage is ready for consumption, the overcap,
75 (which typically is snap-fit to the pourspout, 73) is removed
and the beverage dispensed.
All of the above-described carbonation devices employ an effective
amount of crystalline aluminosilicate molecular sieves containing
at least 5% by weight of carbon dioxide. Preferably such sieves
have a pore size of from about 3 to about 10 Angstroms, and are
present to the extent of from about 0.5 to about 4 grams of
unloaded molecular sieves per fluid ounce of beverage to be
carbonated. Mixtures of sieves having varying pore sizes as
described above may also be employed in these carbonation
devices.
The following Examples serve to illustrate the beverage carbonation
process, compositions and devices of the instant invention. In each
of the Examples a sample of a potable aqueous solution is
carbonated using molecular sieves charged with carbon dioxide. All
of the molecular sieves employed are "loaded" in a packed bed
column through which carbon dioxide is passed at ambient
temperature and at a pressure of about 0.5 psig. In the Examples
the volume of carbon dioxide actually dissolved in a given liquid
sample is determined gravimetrically by driving the carbon dioxide
out of solution by heating and carrying it with a nitrogen purge
into an absorbing bed of Ascarite, commercially available sodium
hydroxide on asbestos.
EXAMPLE I
Several 8 fluid ounce samples of pure water were carbonated with
molecular sieves of varying pore size. All of the molecular sieves
employed were in the form of molded particles incorporating clay
binders. Carbonation in every case took place in a 400 ml. beaker
held at a temperature of 36.degree..+-. 1.degree.F. in an ice bath.
The particular type of sieves employed, the extent to which they
were charged with carbon dioxide and the amount of sieves employed
are summarized in Table 1 below.
Table 1 ______________________________________ Average Loading
Level Amount Pore Size (Wt. Co.sub.2 /Wt. Loaded Utilized Sieve
Type (Angstroms) Sieves .times. 100%) (Grams)
______________________________________ Type 3A 3 8.5 24 Type 4A 4
12.1 12 Type 5A 5 13.4 12 Type 10X 8 14.1 12 Type 13X 10 15.9 12
______________________________________
Volumes of carbonation attained after 1, 2, 3, 4, 6, 10 and 20
minutes were measured in separate carbonation runs. The results are
the basis of FIG. 1 of the drawings and summarized in Table 2
below.
Table 2 ______________________________________ Time of Pore Size
Carbonation Volumes of Sieve Type (Angstroms) (minutes) Carbonation
______________________________________ 3A 3 1 0.146 3 0.300 6 0.360
10 0.750 20 0.595 4A 4 1 0.212 3 0.307 6 0.826 10 0.560 20 0.795 5A
5 1 0.682 2 0.767 4 0.672 6 0.643 10 0.743 10X 8 1 1.210 2 1.230 4
1.180 6 1.120 10 1.200 13X 10 1 1.30 2 1.31 4 1.38 10 1.31
______________________________________
Substantially similar carbonation results are obtained when in
Example I the Type 4A molecular sieves are replaced with the
acid-resistant Type AW-300 molecular sieves and the Type 5A
molecular sieves are replaced with the acid-resistant Type AU-500
molecular sieves.
EXAMPLE II
Four-minute performance factors for 12 and 24 gram sieve batches of
the 3 Angstrom, 4 Angstrom, 5 Angstrom, 8 Angstrom and 10 Angstrom
molecular sieves were calculated by carrying out water carbonation
in accordance with the procedure described in Example I above.
Molecular sieves in each case were loaded with carbon dioxide to
the extent shown in Table 1 above. Results of such four minute
performance factor comparisons are the basis of FIG. 2 of the
drawings and are summarized in Table 3 below.
Table 3 ______________________________________ Sieve Pore Size Four
Minute Performance Factors 12 gram 24 gram (Angstroms) Charged
Sieves Charged Sieves ______________________________________ 3
0.023 4 0.075 0.073 5 0.116 0.141 8 0.307 0.210 10 0.347 0.233
______________________________________
EXAMPLE III
Type 13X, 8 .times. 12 mesh beads loaded with carbon dioxide to the
extent of 15.9% by weight were used to carbonate water in
accordance with the procedures of Example I. Six gram, 12 gram and
24 gram samples were used, and the volumes of carbonation obtained
were recorded for each sample in separate carbonation runs after 1,
2, 4, 6 and 10 carbonation minutes. Results of such carbonation are
summarized in Table 4 below.
Table 4 ______________________________________ Volumes of
Carbonation Time (Minutes) 6 gm batch 12 gm batch 24 gm batch
______________________________________ 1 0.77 1.10 1.40 2 0.91 1.32
1.54 4 0.99 1.32 1.95 6 0.98 1.47 1.37 10 0.95 1.47 1.77
______________________________________
EXAMPLE IV
Type 13X, 8 .times. 12 beads were again employed to carbonate water
in accordance with the procedures of Example III. Four minute
effectiveness factors, efficiency factors, and performance factors
were recorded for a 6 gram, a 12 gram and a 24 gram batch of
molecular sieves loaded with carbon dioxide to the extent of 15.9%
by weight. These results are summarized in Table 5 below.
Table 5
__________________________________________________________________________
Comparison of Four-Minute Performance Factors For Various Batch
Quantities of 8 .times. 12, 13X Beads
__________________________________________________________________________
Quantity Per Unit of Solution Quantity (Grams/ Effectiveness
Efficiency Performance (Grams) Fluid Ounce) Factor (A.sub.4) Factor
(B.sub.4) Factor (P.sub.4)
__________________________________________________________________________
6 0.75 0.611 0.521 0.318 12 1.5 0.855 0.363 0.310 24 3.0 0.994
0.212 0.211
__________________________________________________________________________
Examples III and IV demonstrate that even though more carbon
dioxide is released into solution by utilizing larger amounts of
sieves, the efficiency of carbonation decreases markedly with an
increase in total amount of sieve present. Performance factors are
therefore optimized by employing from about 0.75 to 1.5 grams of
molecular sieves per fluid ounce of beverage.
EXAMPLE V
Several forms of the Type 13X molecular sieves, i.e., 1/16 inch
pellets, 1/8 inch pellets, 8 .times. 12 mesh beads, and 4 .times. 8
mesh beads, loaded as shown in Table 6 with carbon dioxide were
employed in the carbonation of water in accordance with the
procedures of Example I. Carbonation volumes at 1, 2, 4, 6 and 10
minutes (separate carbonation runs) were determined with the
results summarized in Table 6 below.
Table 6 ______________________________________ Time of Volumes of
Carbonation Carbonation 1/16" 1/8" 8 .times. 12 4 .times. 8
(minutes) Pellet.sup.1 Pellet.sup.2 Bead.sup.3 Bead.sup.4
______________________________________ 1 1.30 1.06 1.10 0.90 2 1.31
1.21 1.32 1.38 4 1.38 1.51 1.32 1.67 6 1.01 1.30 1.47 1.55 10 1.31
1.36 1.47 1.52 ______________________________________ .sup.1 Loaded
with 13.2% CO.sub.2 .sup.2 Loaded with 13.7% CO.sub.2 .sup.3 Loaded
with 14.8% CO.sub.2 .sup.4 Loaded with 15.2% CO.sub.2
Substantially similar carbonation results are obtained when the
molecular sieves employed are the powdered form of Type 13X.
Substantially similar carbonation results are obtained when 10
Angstrom acid-resistant molecular sieves having an SiO.sub.2
Al.sub.2 O.sub.3 molar ratio of about 4 and 40% of the exchangeable
metal ions removed or replaced with protons are employed.
EXAMPLE VI
The effect of carbonation with a mixture of 4 Angstrom and 10
Angstrom molecular sieves is demonstrated by employing such a
mixture in the carbonation of water in accordance with the
procedures and CO.sub.2 load levels of Example I. Carbonation
profiles are obtained using 24 grams of 4 Angstrom sieves, 24 grams
of 10 Angstrom sieves and a mixture of 12 grams of 4 Angstrom
sieves and 12 grams of 10 Angstrom sieves, all sieves being in the
form of 8 .times. 12 beads. The resulting carbonation profiles
clearly show that the sieve mixture provides greater initial carbon
dioxide release and dissolution than the 4 Angstrom sieves but
after about 10 minutes of carbonation yields solutions which are
more strongly carbonated than those produced from 10 Angstrom
sieves alone.
EXAMPLE VII
Type 13.times. molecular sieves in the form of 8 .times. 12 mesh
beads and loaded to the extent of 15.9% by weight with carbon
dioxide were utilized to carbonate sweetened solutions to
demonstrate the effect on carbonation of dissolved sweeteners in a
beverage liquid. A 10% sucrose solution, a 10% fructose solution, a
1.45% artifical sweetener (Poly Sweet R, a saccharin based
material, as presently available from the Guardian Chemical
Corporation) solution and pure water were carbonated in accordance
with the procedures of Example I. Carbonation profiles for these
four solutions are summarized below in Table 7.
Table 7 ______________________________________ Time of 10% 10%
Carbonation Pure Sucrose Fructose 1.45% Poly Sweet (minutes) Water
Solution Solution R Solution ______________________________________
1 1.10 0.26 0.53 1.17 2 1.32 0.61 1.06 1.26 4 1.32 1.30 1.52 1.39 6
1.47 1.27 1.36 1.50 10 1.47 1.43 1.35
______________________________________
The above seven examples clearly demonstrate the efficacy of
crystalline aluminosilicate molecular sieves for beverage
carbonation over a wide variety of sieve sizes, sieve quantities,
sieve forms, sieve mixtures, and beverage solutions. The following
examples illustrate several of the carbonation devices which can be
employed to utilize this wide variety of molecular sieve
carbonation techniques.
EXAMPLE VIII
A simple molecular sieve carbonation device was constructed as
follows and used to prepare a orange-flavored carbonated beverage.
Twelve grams of Type 13X molecular sieves in the form of spherical
beads having a mesh size of 8 .times. 12 were loaded with carbon
dioxide to the extent of 15.9% by weight and completely enclosed
within commercially available open mesh polymeric netting, Type
Q225 Delnet, presently manufactured by Hercules, Inc. Such an
assembly is illustrated by FIG. 3 in the drawing.
By submerging this carbonation device below the surface of the
solution comprising 9.1% by weight of a commercially available
orange-flavored beverage powder (as presently sold under the
trademark Kool-Aid) and 90.9% by weight of water, for approximately
10 minutes, a carbonated beverage containing about 1.03 volumes of
dissolved carbon dioxide was obtained.
EXAMPLE IX
A simple carbonation device utilizing carbon dioxide-containing
molecular sieves was constructed as follows: Following the
procedures of Example VIII, 12 grams of charged Type 13X molecular
sieves were enclosed within a Delnet Q225 open mesh netting mounted
on a triangular frame as shown by FIG. 4 in the drawings. The
structural netting assembly was attached to a handle so that the
netting assembly could be held firmly in place with such handle.
The enclosed molecular sieves were then held beneath the surface of
an orange-flavored beverage solution to effectuate carbon dioxide
release. Carbon dioxide dissolution and hence extent of carbonation
was enhanced by using the structured netting assembly as a swizzle
stick to agitate the liquid while carbon dioxide was evolving
through the mesh of the netting assembly. Employment of this device
yielded a carbonated beverage having approximately 1.24 volumes of
dissolved carbon dioxide after 7 minutes of carbonation time. After
13 minutes of carbonation time a beverage having 1.65 volumes of
dissolved carbon dioxide was obtained.
Substantially similar carbonation results are obtained if the Type
13X molecular sieve material is replaced with a crystalline
aluminosilicate having a Zeolite Y structure and an 8 to 10
Angstrom pore size.
EXAMPLE X
A beverage carbonation device is constructed as follows: A
polystyrene container having a volume of approximately 400 ml. if
softened by heating. Five-micron powdered molecular sieves of the
Type 13X are adhered to the soft inside surfaces of the plastic
container to the extent necessary to cover such inside surfaces.
The container is allowed to cool with the hardened plastic
anchoring the sieves in place. The entire container is then
contacted with carbon dioxide to load the molecular sieve powder to
the extent of approximately 20% by weight of the sieves. When
beverage liquid to be carbonated is poured into the container over
ice, the beverage is carbonated to the extent of about one volume
of dissolved carbon dioxide.
Substantially similar carbonation results are obtained when the
powdered molecular sieves are replaced with 4 .times. 8 mesh Type
13X beads which are affixed to the inside surfaces of the drinking
vessel as shown by FIG. 5 in the drawing.
EXAMPLE XI
A beverage carbonation device is constructed as follows: At the
bottom of a cylindrical polystyrene container similar to that
described in Example X, there is placed a cylindrical disc molded
from powdered Type 13X molecular sieves. This disc is affixed to
the bottom of the polystyrene container as shown by FIG. 6 in the
drawing. The molded molecular sieve disc is then loaded with carbon
dioxide to the extent of approximately 20% by weight of the disc.
When beverage liquid is poured into the container, the beverage is
carbonated to the extent of about one volume of dissolved carbon
dioxide. The flat disc provides high initial carbon dioxide release
from the sieve material near its upper surfaces and also provides
sustained carbon dioxide release from the sieve material further
inside the disc. The initial carbon dioxide release is inhibited
if, prior to insertion in the container, the disc is coated with a
film of polyvinyl alcohol.
EXAMPLE XII
A tablet made of Type 13X molecular sieves with 20% by weight of a
clay binder and pressed into a 11/2 inch diameter disc weighing
11.47 grams when charged with CO.sub.2 (16.04% CO.sub.2) was placed
in a 400 ml. beaker containing 8 fluid ounces of water at
35.degree. F. After 4 minutes, 1.22 volumes of carbonation were
measured.
Carbonation greater than about two volumes can be obtained if
carbonation takes place in a closed vessel and the pressure during
carbonation is allowed to rise to about three atmospheres.
EXAMPLE XIII
A beverage carbonation device was constructed as follows:
Forty-eight grams of 8 .times. 12 mesh Type 13X molecular sieves
were loaded to the extent of 16% by weight with carbon dioxide and
mixed with 95 grams of a dry orange-flavored beverage mix. This
sieve and beverage mix combination was placed in a spouted
container having a volume of approximately 1,900 milliliters. A
sheet of polymeric netting (Delnet Type Q225 from Hercules, Inc.)
was then placed across the spout of the container.
Nine hundred forty-six milliters of water at 36.degree.F was placed
in the container and the resulting liquid mixture inside was
agitated by shaking for about 2 minutes. After beverage formation
and carbonation were completed, the carbonated beverage was
decanted through the netting. The resulting beverage contained
approximately 1.4 volumes of dissolved carbon dioxide.
Substantially similar carbonation results are obtained when the
carbonation chamber is a flexible bag as shown by FIGS. 7, 8 and 9
in the drawing.
The above Examples VIII - XIII demonstrate carbonation devices
which can be employed to carry out the molecular sieve carbonation
process of the instant invention.
A variety of dry flavorings, colorings and additives can be mixed
with carbon dioxide loaded molecular sieves to form compositions
which, when added to water form flavorful carbonated beverages.
Such flavorings, colorings and additives are referred to herein as
dry beverage mixes. Typical ingredients in dry beverage mixes can
include flavorings, either natural or artificial, such as cola,
lemon, lime, orange, grape, cherry, root beer, beer, ginger ale,
wine tea, coffee, etc.; colorings, particularly when using
artificial flavorings, of any suitable nature; sweetening agents,
either natural or artificial such as sugars of the glucose,
fructose and sucrose (the former two being preferred over the
latter due to the aforementioned effect on carbonation rate),
saccharin (which exhibits less inhibition of carbonation rates with
molecular sieve carbonation than the natural sugars), etc. Various
other additives well known in the beverage art such as thickeners
and preservatives can also be added.
One highly satisfactory way to provide point-of-use carbonated
beverages is to package a composition consisting of carbon dioxide
loaded molecular sieves of the hereinbefore described types and a
dry beverage mix in the forms and devices herein described or
simply in sealed packets for use in reusable pitchers with netting
or other separation means at the outlet thereof. Examples of
beverages formed from such compositions include the following:
EXAMPLE XIV
A teaspoon of a commercial instant tea and 12 grams of Type 13X
molecular sieves in bead form (approximately 1/8 inch spheres)
loaded with carbon dioxide to about 14.8% by weight are added to 8
fluid ounces of chilled (37.degree.F.) water. A carbonated tea
beverage containing about 1.56 volumes of dissolved carbon dioxide
is obtained.
Substantially similar results are obtained if the dry beverage mix
contains two teaspoons of sucrose in addition to the instant
tea.
Substantially similar results are also obtained if the tea and/or
sugar are coated on the beads of molecular sieve material.
EXAMPLE XV
A dry beverage mix consisting of 44 grams of sugar, 2.4 grams of
freeze dried coffee solids, 5.15 grams of carmel coloring (Sethness
High Acid Proof 150) and 0.02 grams of a food grade silicone
anti-foaming agent is mixed with 49 grams of NaY molecular sieves
(in 1/16 inch extruded pellet form) loaded to 12.9% by weight with
carbon dioxide and the composition is mixed in 2,100 grams of cool
water. A coffee beverage with 1.44 volumes of dissolved carbon
dioxide results.
Substantially similar results are obtained if the molecular sieves
are coated with a water soluble material such as hydroxypropyl
cellulose to allow vigorous mixing to dissolve the coffee while
delaying the release of the carbon dioxide until after said
mixing.
EXAMPLE XVI
Twenty-four grams of a dry beverage mix of the following
composition:
95.55% sucrose
2.5% citric acid
0.5% gum arabic
0.5% natural lemon flavor (dehydrated)
0.5% mono and di-glycerides
0.1% soybean and cotton seed oil
0.25% lemon juice dried with corn syrup
0.1% artificial color
are mixed with 8 grams of CaY molecular sieves in 4 .times. 8 mesh
bead form which are loaded to 13.5% by weight carbon dioxide. The
mixture is added to 8 fluid ounces of water and ice and stirred
until the sugar dissolves. A carbonated lemonade beverage with
about 1.4 volumes of dissolved carbon dioxide results.
Liquid beverage mixes (i.e., concentrates, extracts, syrups, etc.)
of various types can also be prepackaged and used with carbon
dioxide loaded molecular sieves. Examples of this aspect of the
present invention are:
EXAMPLE XVII
Four fluid ounces of a commercial cola fountain syrup (Coca
Cola.sup.TM) are placed in one compartment of a bag such as that
illustrated in FIG. 10. Eighty grams of CaX sieves as 8 .times. 12
mesh spherical beads are loaded with carbon dioxide to 13.7% by
weight, and placed in the other compartment of the bag. The bag is
opened and the sieves and syrup are placed in a seltzer bottle of
about 20 fluid ounce capacity. Five 1 .times. 1 .times. 1 inch ice
cubes are added. The bottle is filled with water and tightly
capped. After about 10 minutes, a carbonated cola beverage with
about 3 volumes of dissolved carbon dioxide (at about 2 atmospheres
pressure) results.
Dry beverage mixes in suitable quantities can also be used with the
above sieve material and seltzer bottle to form carbonated
beverages of other types with about 3 volumes of dissolved carbon
dioxide.
EXAMPLE XVIII
A two compartment bag 6 inches .times. 10 inches of the type shown
in FIG. 10 of the drawings is made of 1 mil polyethylene. 1.5 Grams
of a liquid cola flavored concentrate (Felton International Flavors
PG-189), 2.5 grams of carmel coloring (Sethness High Acid Proof
150), 0.8 grams of 80% concentrated phosphoric acid, 110 grams of a
30.degree. Baume sugar syrup and 880 grams of water are premixed
and placed in one compartment of a bag such as the one illustrated
in FIG. 10. Within the bag and on the other side of the weak medial
seal, 48 grams of Type 10X sieves in 1/8 inch diameter extruced
pellet form and loaded to 13.4% with carbon dioxide are placed. The
medial seal is separated and the bag is stored at 40.degree.F. for
about four hours. The resulting beverage, carbonated to about 2
volumes of carbon dioxide is served by pouring through an 8 mesh
netting.
Many modifications can be made to the present invention as herein
described without departing from the spirit and scope thereof and
within the following claims.
* * * * *