U.S. patent application number 10/319571 was filed with the patent office on 2003-08-14 for apparatus for dispensing an atomized liquid product.
Invention is credited to Dunne, Stephen Terence.
Application Number | 20030150885 10/319571 |
Document ID | / |
Family ID | 9927709 |
Filed Date | 2003-08-14 |
United States Patent
Application |
20030150885 |
Kind Code |
A1 |
Dunne, Stephen Terence |
August 14, 2003 |
Apparatus for dispensing an atomized liquid product
Abstract
The invention is directed to an apparatus for atomizing a liquid
product using a propellant, which may be integrated into aerosol
packs, for atomization of a liquid product. The liquid product may
have a high viscosity. The total flow rate ranges from about 0.5
grams per second to about 0.01 grams per second through a single
capillary tube. The liquid product is atomized within a capillary
tube. The apparatus may be designed as a handheld unit or as a
stationary or mobile unit using a plurality of capillary tubes.
Inventors: |
Dunne, Stephen Terence;
(Suffolk, GB) |
Correspondence
Address: |
SHAW PITTMAN LLP
1650 TYSONS BOULEVARD
MCLEAN
VA
22102
US
|
Family ID: |
9927709 |
Appl. No.: |
10/319571 |
Filed: |
December 16, 2002 |
Current U.S.
Class: |
222/402.24 |
Current CPC
Class: |
B65D 83/62 20130101;
B05B 7/0416 20130101 |
Class at
Publication: |
222/402.24 |
International
Class: |
B65D 083/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 14, 2001 |
GB |
0130057.3 |
Jul 19, 2002 |
WO |
PCT/EP02/08053 |
Claims
What we claim is:
31. An apparatus for atomizing a liquid product using pressure of a
gaseous propellant, wherein the liquid product is atomized within
at least one capillary tube, wherein said apparatus comprises: at
least one capillary tube wherein said tube has one exit port in its
axial direction for discharge of atomized liquid product and
gaseous propellant; at least one entry port into the capillary tube
distant from the exit port; at least one afferent pathway for
delivery of liquid product and propellant in admixture or
separately to the at least one entry port, wherein said afferent
pathway comprises at least one afferent tubing between at least one
entry port and a cavity, wherein said cavity has an internal volume
of below 50 mm.sup.3; and at least one valve for operating the
apparatus.
32. The apparatus according to claim 31, wherein said afferent
tubing carries a substance, wherein said substance is selected from
the group consisting of the liquid product, the propellant, the
liquid product and the propellant, and the liquid product and the
propellant in admixture.
33. An apparatus according to claim 31, wherein the total flow rate
through said capillary tube is from about 0.3 grams per second to
about 0.05 grams per second.
34. An apparatus according to claim 31, wherein the total flow rate
through said capillary tube is from about 0.5 grams per second to
about 0.01 grams per second.
35. The apparatus according to claim 31, wherein at least one
capillary tube comprises: at least one first entry port for entry
of the liquid product wherein said first entry port is arranged
distant from the exit port, and at least one second entry is
arranged distant from the exit port for entry of the propellant; at
least one capillary tube has a sufficient internal diameter and
length between the exit port and the at least second entry port to
allow atomization of entering liquid product by entering
propellant; and the at least one first entry port and the at least
one second entry port have diameters to allow entrance of liquid
product and gaseous propellant in a volumetric flow ratio of liquid
product to gaseous propellant that is from about 1:50 to about
1:5000.
36. The apparatus of claim 35, wherein said volumetric flow ratio
is from about 1:100 to about 1:300.
37. An apparatus according to claim 31, wherein the entry port
comprises: (a) at least one first entry port for entry of the
liquid product that is arranged distant from the exit port and (b)
at least one second entry port for entry of the gaseous propellant,
wherein said at least one second entry port is arranged between the
first entry port and the exit port; the at least one capillary tube
has a sufficient internal diameter and length between the exit port
and the at least second entry port to allow atomization of entering
liquid product by entering propellant, and the at least one first
entry port and the at least one second entry port have diameters to
allow entrance of liquid product and gaseous propellant in a
volumetric flow ratio of liquid product to gaseous propellant that
is from about 1:50 to about 1:5000,.
38. The apparatus of claim 37, wherein said volumetric flow ratio
is from about 1:100 to about 1:300.
39. An apparatus according to claim 31, wherein said entry port
comprises: (a) at least one first entry port for entry of the
liquid product is arranged distant from the exit port, wherein said
first entry port is arranged axially at the end of the capillary
tube opposite to the exit port, and (b) at least one second entry
port for entry of the gaseous propellant is arranged between the
first entry port and the exit port; the at least one capillary tube
has a sufficient internal diameter and length between the exit port
and the at least second entry port to allow atomization of entering
liquid product by entering propellant; and the at least one first
entry port and the at least one second entry port have diameters to
allow entrance of liquid product and gaseous propellant in a
volumetric flow ratio of liquid product to gaseous propellant that
is from about 1:50 to about 1:5000.
40. The apparatus of claim 39, wherein said volumetric flow ratio
of liquid product to gaseous propellant is from about 1:100 to
about 1:300.
41. An apparatus according to claim 31, wherein said entry port
comprises at least one entry port for entry of the liquid product
and of the propellant that is arranged distant from the exit port;
the at least one capillary tube has a sufficient internal diameter
and length between the exit port and the at least one entry port to
allow atomization of entering liquid product by entering
propellant; the at least one entry port has a diameter to allow
entrance of liquid product and finally gaseous propellant in a
volumetric flow ratio of liquid product to finally gaseous
propellant is from about 1:50 to about 1:5000; said liquid product
is pressurized by gaseous propellant, wherein said liquid product
is mixed with liquefied propellant within a compartment which is
connected to one afferent pathway, wherein said afferent pathway is
disposed for delivering both the liquid product and the liquefied
propellant to the at least one entry port without a lateral opening
in the afferent pathway.
42. The apparatus of claim 41, wherein said volumetric flow ratio
of liquid product to gaseous propellant is from about 1:100 to
about 1:300.
43. The apparatus according to claim 31, wherein pressure is
applied to form a gaseous phase only, wherein said gaseous phase is
essentially separated from the liquid product, the at least one
entry port for entry of the liquid product and of the gaseous
propellant is arranged at the end of the at least one capillary
tube opposite to the exit port; the at least one capillary tube has
a sufficient internal diameter and length between the exit port and
the at least one entry port to allow atomization of entering liquid
product by entering propellant; the at least one entry port has a
diameter that allows entrance of liquid product and gaseous
propellant in a volumetric flow ratio of liquid product to gaseous
propellant that is from about 1:50 to about 1:5000; wherein the
liquid product is pressurized by the gaseous propellant contained
within the same container, wherein the afferent pathway is disposed
for delivering the liquid product to the entry port; and the
afferent pathway has a lateral opening for entry of gaseous
propellant separate from liquid product and wherein the afferent
pathway between the lateral opening and the entry port has only
small internal cavities to allow for a non-oscillating flow of
liquid product and gaseous propellant in the capillary tube.
44. The apparatus of claim 43, wherein said volumetric flow ratio
of liquid product to gaseous propellant is from about 1:100 to
about 1:300.
45. The apparatus according to claim 41, wherein the afferent
pathway provides an afferent tubing with an axial opening arranged
within the vicinity of the end of the container that is opposite to
the capillary tube and wherein said afferent tubing has a large
inner diameter to allow the atomization of liquid product when the
container is inverted such that the axial opening of the afferent
tubing is not immersed in the mixture of liquid product and
propellant.
46. The apparatus of claim 31, wherein the distance, between the
exit port and the at least one entry port for entry of the gaseous
propellant, is from about 5 mm to about 100 mm,.
47. The apparatus of claim 46, wherein said distance is from about
5.0 mm to about 50 mm.
48. The apparatus of claim 31, wherein the first entry port has a
diameter of from about 0.1 mm to about 1.0 mm.
49. The apparatus of claim 48, wherein said diameter is from about
0.2 mm to about 0.6 mm.
50. The apparatus according to claim 31, wherein the diameter of
the capillary tube is locally reduced by at least one flow
restrictor, inserted either between the exit port and the adjacent
entry port and/or between the first and second entry ports.
51. The apparatus according to claim 31, wherein the cavity is
formed between at least one afferent tubing and at least one entry
port of said capillary tube, wherein said cavity has an internal
volume of below 20 mm.sup.3.
52. The apparatus of claim 51, wherein said volume is below 6
mm.sup.3.
53. The apparatus of claim 51, wherein said volume is below 2
mm.sup.3.
54. The apparatus according to claim 31, wherein one valve is
arranged on the capillary tube between the exit port and the
adjacent entry port.
55. The apparatus according to claim 31, wherein valves are
arranged each at the first and second entry ports.
56. The apparatus according to claim 31, wherein a nozzle is
provided at the exit port.
57. The apparatus according to claim 31, wherein the capillary tube
is bent.
58. The apparatus according to claim 31, wherein the capillary tube
is coiled.
59. The apparatus according to claim 31, wherein a stopper is
provided within the afferent pathway for blocking it and then
opening an alternative pathway to allow the atomization of liquid
product when the apparatus is turned to a position upside down, by
which the atomizing capillary tube points downwards.
60. The apparatus according to claim 31, wherein a filter mesh or
membrane, which is permeable to gas but impermeable to liquids is
arranged at the entry port(s) for propellant within the afferent
pathway.
61. The apparatus according to claim 31, wherein said at least one
capillary tube is comprised of a plurality of capillary tubes,
wherein each of said tubes comprises: (a) one exit port in the
axial direction for discharge of liquid product and gaseous
propellant, and (b) one entry port that is distant from the exit
port of said tube; and further wherein said cavity is formed
between afferent tubing to every single capillary tube and at least
one entry port into every single capillary tube, wherein said
cavity has an internal volume of below 50 mm.sup.3 for every single
internal cavity.
62. The apparatus according to claim 61, wherein said plurality of
capillary tubes are arranged parallel to each other.
63. The apparatus according to claim 61, wherein said plurality of
capillary tubes are arranged in a bundle.
64. The apparatus according to claim 61, wherein said plurality of
capillary tubes are inclined with respect to each other.
65. The apparatus according to claim 61, wherein each capillary
tube, of said plurality of capillary tubes, is connected to the
same source of liquid product and to the same source of
propellant.
66. The apparatus according to claim 61, wherein the capillary
tubes, of said plurality of capillary tubes, are connected in
groups to containers containing different liquid products and
different propellants.
67. The apparatus according to claim 61, wherein the capillary
tubes, of said plurality of capillary tubes, are connected to
pipelines for the supply of liquid product and of propellant.
68. A process for dispensing a liquid product using the apparatus
of claim 31.
69. The process according to claim 68, wherein the flow rate of the
liquid product through a single capillary tube is from about 0.01
grams per second to about 0.4 grams per second.
70. The process according to claim 68 or claim 69, wherein the
liquid product is selected from the group consisting of cosmetic
preparations, paint compositions, chemically active compositions,
foaming compositions, lubricants and fuels.
71. The process according to claim 61, wherein the propellant is
selected from the group consisting of: (a) compressed gas, wherein
said compressed gas is selected from the group consisting of
compressed air, compressed nitrogen, compressed carbon dioxide,
compressed hydrocarbon, compressed helium, and compressed neon; (b)
liquefied gases, wherein said liquefied gases are selected from the
group consisting of: liquefied gases free of halogens, liquefied
gases free of propane, liquefied gases free of butane, liquefied
gases free of pentane, liquefied gases free of ether, liquefied
gases free of dimethylether, and liquefied gases free of
diethylether; (c) halogenated liquefied gases; (d) a mixture of
gases; and (e) a mixture of liquefied gases.
Description
[0001] This application claims priority to Great Britain
Application No. 0130057.3, filed on Dec. 14, 2001, and
PCT/EP02/08053 filed on Jul. 19, 2002, both of which are herein
incorporated by reference in their entirety.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates generally to an apparatus for
atomizing a liquid product which can be integrated into aerosol
packs, which may be pre-pressurized. Such an apparatus may be
integrated into a spray can, which is operable by simply pushing a
closure mechanism to open valves for dispensing the contents of the
can.
[0004] 2. Background of the Invention
[0005] A conventional apparatus for atomizing a liquid product
containing the actual active ingredient uses pressure from a
propellant, which is contained within a conventional storage
container connected thereto or alternatively a pump to pressurize
the storage container. Such known devices use a tube to transport
the liquid product to be atomized to an atomizing nozzle where
droplets are formed from the liquid product. In order to
effectively atomize a liquid product by a conventional atomizing
apparatus, comparatively large volumes of propellant, diluent
and/or solvent, in relation to the liquid product are necessary,
both for providing sufficient pressure for the atomization process
and for reducing the viscosity of the liquid product, that has the
actual active ingredient of the system. The propellant is
conventionally used in a volumetric ratio of 2000:1 to 20,000:1 of
gas to liquid product, when determined at atmospheric pressure. The
propellant may be compressed air, nitrogen, or, conventionally a
volatile organic compound such as butane and chlorinated or
fluorinated hydrocarbons, which are liquid in a compressed
state.
[0006] In conventional systems, the liquid product has to be
diluted further by additional solvents, or diluents (such as, for
example, liquefied natural gas), which also act as the propellant
and reduce the amount of active ingredient atomized at the
conventional high flow rates and/or reduces the viscosity of the
active ingredient. The propellant itself may act as a solvent
and/or diluent for the liquid product when contained within the
same compartment as the liquid product, (such as, for example, when
the propellant is liquefied natural gas, butane, chlorinated
hydrocarbons, or fluorinated hydrocarbons). When both liquid
product and propellant are contained within the same storage
container, such as in the conventional "dip tube" systems, some of
the propellant may disperse or dissolve into the liquid product, In
order to reduce such high total flow rates of known dip-tube
systems, they conventionally need a so-called vapor tap to allow
inflow of additional propellant in its gaseous state, which reduces
the flow rate of liquid mixture up the dip-tube. This reduction of
the flow rate by additional gaseous propellant is used in
conventional systems to reduce the amount of liquid product which
is dispensed while maintaining a sufficiently high total flow rate
which is necessary for a stable atomization.
[0007] In conventional systems, when liquid product is being
dispensed, the effect of the propellant to act as a solvent or
diluent for the liquid product is significantly reduced as the
propellant changes into its gaseous phase, and becomes no longer
available as a liquid solvent.
[0008] An apparatus for atomizing liquid product is disclosed in
U.S. Pat. No. 5,921,439, which uses a nozzle to atomize a mixture
of pressuring gas and liquid product. The liquid product and
pressurizing gas form a mixture immediately before entering the
atomizing nozzle, but are delivered to the mixing compartment by
separate tubes. In the storage compartments, the pressurizing gas
exerts its pressure also on the liquid product, which is isolated
from the pressurizing gas within a collapsible bag, surrounded by
pressurizing gas.
[0009] U.S. Pat. No. 5,918,817 discloses a two-fluid cleaning jet
nozzle, which has an atomizing unit by which pressurized gas can
atomize a liquid into droplets. The cleaning jet nozzle in U.S.
Pat. No. 5,918,817 consists of two portions, namely a so-called
atomizing tube and a cross-sectional area of 7-200 mm.sup.2 into
which the liquid and gas are introduced. This atomizing tube is
provided with one exit port, which continues into an accelerating
tube having a smaller diameter than the atomizing tube, namely 3-15
mm.sup.2. As a result of the smaller cross-sectional area of the
accelerating tube being fed from the atomizing tube which has a
larger cross-sectional area, the velocity of the exiting fluid
droplets is much higher than for conventional nozzles without a
smaller diameter accelerating tube adjacent to the atomizing tube.
This two-compartment jet nozzle provides almost double the exit
velocity of atomized fluids at the same pressure of the propellant
gas in comparison to the conventional jet nozzle, i.e., approaching
the speed of sound at a supply pressure of gas about 3 bar. It
becomes clear from the drawing, that the entrance port for the gas
is always of a bigger cross section than the entrance port for
liquid. U.S. Pat. No. 5,918,817 emphasizes the importance of a high
velocity and a high volume to be obtained for the stream of liquid
droplets in order to effectively remove contamination from the
surface of silicon wafers.
[0010] Conventional aerosol spray systems typically produce flow
rates of 0.5 to 3 grams-per-second (g/s) of product, where the
product is a mixture of liquefied propellant gas, a diluent or
solvent and a small amount of active ingredient. In these systems,
both the propellant gas and the diluent or solvent are often
volatile organic compounds, such as butane and ethanol. These
volatile organic compounds are included to produce a spray with a
"cool feel" as they quickly evaporate leaving behind just the
active ingredient on the sprayed surface (such as, for example the
skin) or suspended in the air. Conventionally, a mixture of organic
compounds is needed for adjusting the viscosity and solvency of the
active ingredient (i.e., a liquid product without added volatile
organic compounds). The volumetric ratio of gas (at atmospheric
pressure) to active liquid product is typically between 2000:1 and
20,000:1. The propellant gas, the solvents and diluents are
released into the atmosphere, which generates environmental
problems.
[0011] It has been shown that conventional valve arrangements for
atomizing apparatuses necessitate the use of flow rates of
propellant and liquid product including any diluents in the order
of 0.5 grams per second to 1.5 grams per second in order to avoid
unstable (i.e., oscillating) flow. With lower total flow rates, the
flow at the exit port becomes unstable and discontinuous, i.e., it
oscillates. In order to reduce such high flow rates of propellant,
dip-tube systems conventionally need a so-called vapor tap to allow
inflow of additional propellant in its gaseous state.
[0012] The design of conventional atomizing valves usually has an
internal cavity volume arranged between afferent pathways for
delivering liquid product and/or propellant and the exit. For
example, the atomizing nozzle is at least 100 mm.sup.3 and the
total cavity volume, including valve body, stem and actuator, is
between 100 and 300 mm.sup.3.
SUMMARY OF THE INVENTION
[0013] Therefore, it is an object of the present invention to
provide an apparatus for atomizing a liquid product that can form
small liquid droplets using the pressure of a propellant while
requiring a significantly reduced amount of propellant gas in
relation to the liquid product being atomized. For the purposes of
this disclosure, the term "liquid product" refers to a composition
that is in a liquid state at room temperature, contains the active
ingredient, which is formulated as a solution, suspension, or
dispersion (such as, for example, hairspray, a paint composition)
containing the diluent only necessary for formulating the active
ingredient such as soluble resins or dispersible particles (for
example, paints or hairspray), without necessarily incorporating
additional diluents in admixture.
[0014] It is a further object of the present invention to provide
an apparatus for atomizing a liquid product the using pressure of a
propellant to effectively atomize a liquid product, having a higher
viscosity than for example water, into small droplets while
requiring a reduced amount of propellant.
[0015] It is a further object of the present invention to provide
an apparatus for atomizing a liquid product, wherein the liquid
product may be viscous, for example having a viscosity above that
of, for example, water, in order to avoid the use of a diluent
contained in the liquid product.
[0016] Furthermore, it is an object of the present invention to
provide an apparatus for atomizing a liquid product, in which the
liquid product may be viscous, using a comparatively low proportion
of propellant to liquid product dispensed, while providing for a
non-oscillating (i.e., stable) stream of atomized liquid product at
the exit port.
[0017] In one embodiment, the present invention arrives at the
objects of the invention by providing an apparatus for atomizing a
liquid product, using the pressure of a gaseous propellant. The
liquid product is atomized within a capillary tube. The apparatus
of the present invention is designed for a total flow rate from
about 0.5 grams per second to about 0.01 grams per second,
preferably from about 0.3 grams per second to about 0.05 grams per
second through a single capillary tube. Further embodiments of the
apparatus and of the process of the present invention are described
in the instant specification, including the claims.
[0018] The apparatus contains at least one capillary tube. One
axial opening of the capillary tube is used for the discharge of
the atomized liquid product, i.e., as an exit port. Also arranged
on the capillary tube is at least one first entry port for entry of
the liquid product which is distant from the exit port. At least
one second entry port may be provided for entry of the propellant.
By properly dimensioning the diameter of the capillary tube and the
length or distance between the exit port and an adjacent entry
port, either a first or a second entry port, the entering liquid
product is atomized within the capillary tube by entering
propellant.
[0019] The liquid product is delivered to the first entry port by a
pipe or tube, the propellant is delivered to the at least one
second entry port by a separate pipe or tube. Depending on the type
of storage container connected to this apparatus, a liquid product
may be contained within the same container as the propellant or may
be separated from the propellant.
[0020] In one embodiment of the atomizing apparatus of the present
invention, essentially no propellant functions as a diluent for the
liquid product and the two components are separated and fed to
their respective entry ports essentially separately. In one
embodiment of the present invention in which liquid product and
propellant are kept separated from each other, the propellant may
still pressurize the liquid product, which may be contained for
example in a collapsible bag or in a cylinder having a movable
piston being pushed by the propellant, where the cylinder is
arranged within a canister containing the propellant. The, liquid
product and propellant can be separated from each other by phase.
When compressed gases, such as air or nitrogen, are used as the
propellant, the compressed gases do not form a liquid phase at the
pressure used. These compressed gases may be in direct contact with
the liquid product, although a small amount of dissolution of the
gas phase into the liquid product may occur.
[0021] In a preferred embodiment of the present invention, the
first entry port is formed by the axial opening of the capillary
tube opposite to the exit port and the at least one second entry
port is arranged between the two axial openings.
[0022] In an embodiment of the present invention, a capillary tube
has an inner diameter of from about from about 0.1 mm to about 1.0
mm, preferably from about 0.2 mm to about 0.6 mm. An essential
feature of the present invention regarding the length of the
capillary or distance between exit and entry port is that the
length or distance between the exit port and the adjacent entry
port, either a first or a second entry port, covers a range from
about 5 mm to about 100 mm, preferably from about 5 mm to about 50
mm.
[0023] The diameters of the first and second entry ports are
designed such that at normal atmospheric pressure, a volumetric
flow ratio of liquid product to propellant is adjusted from about
1:50 to about 1:5000, preferably from about 1:100 to about 1:300,.
In general, the first entry port has a diameter of from about 0.1
mm to about 2.0 mm, preferably from about 0.2 mm to about 1.0 mm,
more preferably from about 0.3 mm to about 1.0 mm, even more
preferably from about 0.4 mm to about 0.7 mm. When used, the second
entry port generally has a diameter from about 0.1 mm to about 0.7
mm, preferably from about 0.15 mm to about 0.50 mm, more preferably
from about 0.24 to about 0.35 mm.
[0024] The diameter of the first entry port may be formed by a flow
restrictor when the first entry port is the axial opening of the
capillary tube. Such a flow restrictor may be formed by an insert
into the capillary tube, decreasing its inner diameter.
Furthermore, such a flow restrictor, which decreases the inner
diameter of the capillary tube, may be inserted into the capillary
tube between the exit port and the adjacent entry port.
[0025] As an alternative to using a separate first and second entry
port for delivering liquid product and propellant to the capillary
tube, respectively, another embodiment of the present invention
utilizes an admixture of liquid product and propellant that is fed
to the capillary tube, having just one entry port. For this
embodiment, the same dimensions as described for the capillary tube
apply. As the single entry port, for example, the axial opening
opposite to the exit port may be used.
[0026] The embodiment of the present invention, which uses a common
afferent pathway for both liquid product and propellant to the
capillary tube, is applicable for instance in so called "dip-tube"
systems, in which wherein the afferent pathway consists of a tubing
reaching down into the liquid phase of admixed liquid product
together with liquefied propellant, which may be liquefied
hydrocarbon, optionally chlorinated or fluorinated and connective
cavities to the entry port of the capillary tube.
[0027] For the embodiments having one common afferent pathway for
both the liquid product and the propellant, when using a propellant
which forms a liquid phase at the pressure used, generating a
liquid admixture of liquefied propellant with the liquid product
itself, the afferent pathway has no need for a lateral opening,
also referred to as vapor tap. However, when a compressed gas is
used as the propellant, which is phase-separated from the liquid
phase (such as, for example, compressed air or nitrogen) the
dip-tube needs a lateral opening for admitting propellant into the
afferent pathway in a section of the dip-tube which is not immersed
in liquid product when the container is in the position where it is
actuated to dispense liquid product.
[0028] Furthermore, in the embodiment of the present invention
applicable to the "dip-tube", wherein the liquid propellant forms
one phase with the liquid product itself, i.e., the liquid
propellant is separated by phase or physical barriers from the
liquid product, the present invention achieves the atomization of
liquid product within the capillary tube using only propellant
forming a liquid phase with a liquid product, without the need for
an additional entry opening within the afferent tubing (i.e.,
additional entry port or vapor tap) to allow entrance of additional
gaseous propellant. An additional entry port (also called a vapor
tap, which allows the additional entrance of gaseous propellant
into the atomizing unit), is not necessary for the present
invention, when liquefied gases are used to form a liquid phase as
the propellant
[0029] Furthermore, it is an essential feature of the present
invention that the low flow rate of propellant in relation to
liquid product, when compared to conventional systems, allows the
liquid product to atomize without oscillations in the flow at the
exit port, i.e., without discontinuous bursts out of the exit port.
In order to achieve a stable and continuous ( i.e.,
non-oscillating) flow of atomized liquid product out of the exit
port, when using a comparatively low volumetric ratio of liquid
product to propellant, and a comparatively low volumetric total
flow rate of propellant and liquid product, the apparatus and
process of the present invention provide internal dimensions of the
afferent pathways to the capillary tube that avoid internal spaces
and cavities. In an embodiment of present invention, the afferent
tubing's and pipes or the single pipe in the case of the dip-tube
system, are connected to the capillary tube, and include interposed
valve mechanisms in which the internal cavities are not large
enough to produce an oscillating flow under the conditions
described.
[0030] The internal cavity formed between afferent tubing and entry
port into the capillary tube has a volume of below about 50
mm.sup.3, preferably below about 20 mm.sup.3, more preferably below
about 6 mm.sup.3 and most preferably below about 2 mm.sup.3.
[0031] With the low total volumetric flow rate, the present
invention achieves the same liquid product (active ingredient) flow
rate as in conventional systems; however, the diluents necessary in
conventional systems can be omitted to a substantial degree. One
reason why the present invention can achieve this results is that
the high viscosity of the liquid product is no longer an obstacle
to atomization at low total flow rates. Another reason, more
importantly, is that the present invention uses only comparatively
low total flow rates of liquid product plus propellant.
[0032] In general, the combination of low total flow rate of
propellant and liquid product and the low ratio of propellant to
liquid product, which can be realized with the atomization
apparatus according to the present invention, allows liquid product
(active ingredient) to be dispensed at the same rate as
conventional systems; however, the apparatus and process of the
present invention use less propellant and substantially less
diluents than necessary in conventional systems.
[0033] The volume of cavities containing the admixture of liquid
product and propellant in the apparatus of the present invention,
which are created between the one or more afferent tubings and the
actual atomizing capillary tube, need to be controlled to be under
a certain volume in order to allow continuous and stable (i.e.,
non-oscillating) flow to the exit port while still using low total
flow rates and, additionally, low ratios of propellant to liquid
product.
[0034] The apparatus of the present invention provides an inner
diameter of the capillary tube atomizer that affects the flow rate
of the atomized liquid product inside the capillary.
[0035] Persons of skill in the art can determine the maximum cavity
volume, which is defined as the void volume between the afferent
pathway(s) for liquid product and/or propellant and the entrance
port(s) to the capillary tube, to determine the dimensions
applicable in the present invention. As a guideline, the following
considerations can be followed:
[0036] At a viscosity of 50 mPa.multidot.s (for example vegetable
oil) the relationship can be calculated as:
Maximum cavity volume allowed=Pressure.sup.1.5 exp
[(d/R-0.621)/0.2022]
[0037] At a viscosity of 1 mPa.multidot.s (for example water) this
relationship changes to:
Maximum cavity volume allowed=Pressure.sup.1.5
exp[(d/R-0.4274)/0.1917],
[0038] where d is the capillary tube internal diameter in mm, and
wherein R is the ratio of the diameters of the entry port for
propellant to the entry port (which was a 40 mm long capillary
tube) for liquid product (which may be defined by a restrictor
inserted into the axial opening of the capillary tube), and wherein
the internal diameter of the capillary tube is given in mm, the
pressure is gauge and is given in bars and the maximum volume
cavity allowed is calculated in mm.sup.3.
[0039] If a larger cavity volume is used that is larger than or
above the maximal cavity volume allowed, then an unstable and/or
oscillating flow is created when using the intended total flow
rate.
[0040] From the above considerations, a person of skill in the art
can determine the volumes of sufficiently small cavity, when using
values for viscosity and geometry that differ from those given
above, in order to provide a capillary tube atomizer which produces
a continuous (i.e., non-oscillating) flow of the atomized liquid
product at low ratios of propellant to liquid product.
[0041] Furthermore, the above relations show that, for a given
system, an increase in R or a decrease in the pressure applied can
lead to unstable or oscillating flows.
[0042] Embodiments of the present invention that provide the above
relationships are described in the following examples. In a
preferred embodiment, the cavity volumes are reduced by a factor of
10 to 100 as compared to the cavity volumes of conventional systems
in order to arrive at a non-oscillating atomization of liquid
product when using comparatively lower ratios of propellant to
liquid product. In preferred embodiments according to the present
invention, the cavity volume between the afferent pathway(s) and
the entry port(s) to the capillary tube is between 0 and 20
mm.sup.3 and preferably below 10 mm.sup.3.
[0043] In the above calculations, when applied to a dip-tube system
using just one afferent pathway between storage container and
capillary tube with no additional opening within the afferent
pathway for entrance of additional propellant, the ratio R becomes
1 and is to be replaced by the volumetric ratio of propellant to
liquid product within the uniform mixture of liquid product and
propellant.
[0044] In order to operate this atomizing apparatus embodiment of
the present invention, valves are used to open and to shut off the
flow of the liquid product and/or propellant and/or the mixture of
liquid product and propellant before the exit port. Therefore, a
single on/off valve may be arranged on the capillary tube between
the exit port and the adjacent entry port to completely block the
capillary tube cross-section. In addition, or as a separate
embodiment, two valves may be arranged to separately block or
regulate the flow of propellant to the second entry port and the
flow of liquid product to the first entry port. These two valves
may be actuated in parallel and simultaneously. Further, in order
to avoid liquid product accumulating in the capillary tube, the
valve controlling the inflow of propellant into the second entry
port may be used to admit propellant shortly before and after entry
of liquid product.
[0045] For the purposes of the specification, pressures given are
defined as pressure gauge, i.e., the pressure above normal
atmospheric pressure, unless otherwise indicated.
[0046] The propellant may be natural gas, such as for example
liquefied butane, propane or a halogenated or fluorinated
hydrocarbon. However, an environmentally friendly propellant such
as compressed air or nitrogen may be used as the propellant. In
some cases, such as when low flow rates of propellant are
necessary, even compressed carbon dioxide, compressed air or
nitrogen may be used as the propellant.
[0047] When dimensioning the atomizer according to the invention,
it is to be taken into account that the geometry will influence the
flow rates of liquid product and propellant as well as the particle
size of the droplets of liquid product produced. In detail, the
particle size essentially depends on the ratio of diameters of
first entry port to second entry port.
[0048] Generally, the lower this ratio, the smaller the particles
will be when both liquid product and propellant are under the same
pressure.
[0049] The flow rate at the exit port is mainly a function of the
inner diameter of capillary tube, such as, for example, a smaller
inner diameter of the capillary tube will result in a lower flow
rate at the same pressure for propellant and liquid product.
[0050] In accordance with the particle size being influenced by the
ratio of cross-sections of the first entry port to the second entry
port, the particle size is accordingly influenced by the volumetric
ratio of liquid product to propellant. The lower the ratio of
liquid product to propellant, the smaller the particles will be at
the exit port.
[0051] Therefore, the following measures are to be taken to adjust
the dimensions of the atomizer according to the invention: If the
particles produced at the exit port are too big, the ratio of
liquid product to gas is decreased. In embodiments in which the
liquid product is stored separate from the propellant (such as, for
example, the liquid product contained within a collapsible bag
compressed by the propellant), the ratio of the diameter of the
first entry port to the diameter of the second entry port is
decreased. In the case for the dip-tube arrangement embodiment,
wherein propellant gas and liquid product are contained within the
same canister, the volumetric ratio of liquid product to propellant
shall be decreased.
[0052] In order to decrease the flow rate and the cross section of
the exit port, the inner diameter of the capillary tube is
decreased, or, alternatively, the ratio of liquid product to
propellant is decreased.
[0053] When an acceptable particle size is initially obtained with
a flow rate that is too high at the exit port, the flow rate can be
regulated by decreasing the inner diameter of the capillary tube or
inserting flow restrictors into the capillary tube. Further, when
an acceptable particle size is initially obtained with a flow rate
that is too low at the exit port, the flow rate can be regulated by
increasing the inner diameter, i.e., the cross-section of the
capillary tube.
[0054] When the flow rate at the exit port that is initially
obtained is acceptable but the droplets produced are too large in
size, the droplet size is decreased by decreasing the ratio of
liquid product to propellant and increasing the inner diameter of
the capillary tube. When the particles produced at the exit port
are too small but the flow rate initially obtained is acceptable,
the particles are enlarged by increasing the ratio of liquid
product to propellant and either decreasing the inner diameter of
the capillary tube or inserting flow restrictors.
[0055] In one embodiment of the present invention, the apparatus is
used to atomize liquid products having a dynamic viscosity from 0.3
mPa.multidot.s to 5000 mPa.multidot.s.
[0056] The following design examples of the apparatus and process
according to the present invention indicate the dynamic viscosity
of the liquid product. In these examples, the liquid product was
contained within a collapsible bag surrounded by propellant gas,
both placed within a closed canister. The pressure of the
propellant gas was approximately 3 bar gauge. For the purposes of
this specification, unless otherwise indicated, the pressures given
are defined as pressure gauge, i.e., the pressure above normal
atmospheric pressure.
[0057] In the following example, the first entry port is the axial
opening of the capillary tube, the second entry port was arranged
at a distance of 20 to 40 mm from the exit port.
1TABLE 1 diameter diameter capillary dynamic of first of second
tube viscosity entry port entry port diameter Example [mPa
.multidot. s] [mm] [mm] [mm] 1 1-3 0.3-0.4 0.15-0.29 0.3-0.4 2 3-10
0.4-0.7 0.24-0.35 0.4-0.7 3 10-20 0.4-0.7 0.24-0.35 0.4-0.7 4 20-40
0.7-1.0 0.28-0.50 0.7-1.0
[0058] Examples 5 and 6 were performed with a setup separating the
liquid product from the propellant at a pressure of 2 bar and a
distance of 40 mm between the exit port of the capillary tube and
the adjacent second entry port, with the first entry port being the
axial opening of the capillary tube opposite to the exit port.
2TABLE 2 diameter diameter capillary mass mean dynamic of first of
second tube diameter of viscosity entry port entry port diameter
droplets Example [mPa .multidot. s] [mm] [mm] [mm] [.mu.m] 5 13 0.4
0.29 0.4 40 6 13 0.4 0.35 0.4 24
[0059] In a further embodiment of the present invention, the liquid
product may be stored in a long tube having a diameter that
provides a constant flow of liquid into the first entry port, if
the valves are open. Such a tube may include a series of internal
restrictions that permit the effective length of the tube to be
reduced and, as the liquid is used up, less pressure is then
required to create the desired flow of liquid and a decreasing
pressure resulting from the compressed gas propellant being used up
can be compensated by selecting tube length, tube diameter and
restrictors. The droplet size was measured using a laser
diffraction system, namely a Malvern particle size analyzer.
TABLES 3A and 3B
[0060] Examples of dimensions for an atomizing apparatus with a
storage compartment for liquid product that is separated from
propellant, pressurizing the liquid product (bag-on-valve-type)
3TABLE 3A Atomized liquid product: oil (50 mPa .multidot. s)
Diameter of Diameter of Diameter Flow entry port entry port of rate
Cavity for for liquid capillary (grams/ Volume propellant product
Pressure tube second) 130 mm.sup.3(a) 0.5 mm 1.0 mm 2.7 bar 0.50 mm
0.60 g/s Example 1 0.5 mm 1.0 m 2.7 barr 0.27 mm 0.15 g/s 6
mm.sup.3 Example 2 0.5 mm 1.0 mm 2.7 bar 0.17 mm 0.06 g/s 2
mm.sup.3 (a) comparative example for a conventional spray can
[0061]
4TABLE 3B Atomized liquid product: water (1 mPa .multidot. s)
Diameter of Flow Diameter of entry port Diameter rate entry port
for liquid of (grams Cavity for product capillary per Volume
propellant (restrictor) Pressure tube second) 130 mm.sup.3(a) 0.27
mm 0.4 mm 2.7 bar 0.55 mm 0.60 g/s Example 3 6 mm.sup.3 0.27 mm 0.4
mm 2.7 bar 0.24 mm 0.12 g/s Example 4 2 mm.sup.3 0.27 mm 0.4 mm 2.7
bar 0.14 mm 0.04 g/s (a) comparative example for a conventional
spray can
[0062] A graphic representation of the results in Tables 3A and 3B
is given in FIG. 1.
APPLICATION EXAMPLES
[0063] In the following, two embodiments of the apparatus according
to the invention are compared for the same liquid product. The
"bag-on-valve type" atomizing apparatus used a propellant, which is
exchangeably compressed gas such as air or nitrogen, which does not
form a liquid phase at the pressures employed, as well as liquid
natural gas. The propellant is contained within a container and has
access to the capillary tube atomizer via a lateral entry port of
the afferent pathway, whereas the liquid product is contained
within a physically separated compartment such as a collapsible bag
or a cylinder with a movable piston, which compartment is connected
to the afferent pathway, for example to one axial opening of an
afferent tubing forming part of the afferent pathway.
[0064] The alternative embodiment, here termed "dip-tube", employs
one afferent pathway to the atomizing capillary tube, which
afferent pathway does not have an additional entry port for e.g.
gaseous propellant. In contrast, the afferent pathway only has one
opening, for example the axial opening of an afferent tubing, which
connects to the pathway leading to the capillary tube atomizer.
Accordingly, a mixture of liquid product and liquid propellant
enters into the afferent pathway, which mixture is not changed in
respect of its ratio of propellant to liquid product by additional
propellant entering the afferent pathway in its gaseous form.
5 TABLE 4 Bag-On-Valve Dip-Tube Total flow rate of liquid 0.02-0.2
grams per 0.05-0.3 grams per product plus propellant second (or
higher) second (or higher) Viscosity of liquid product 1-50 mPa
.multidot. s 1-50 mPa .multidot. s (active ingredients including
solvents) Propellant (volume) 20-80% 20-80% Size of atomized
particles 20-100 .mu.m (a) 20-100 .mu.m (a) Spray angle 18.degree.
(16.degree.-20.degree.) 18.degree. (16.degree.-20.degree.) (a) mass
mean diameter
[0065]
6TABLE 5 The following compositions for a hairspray may be used to
produce exactly the same particle size and spray angle of atomized
liquid product. Composition for bag-on-valve or Composition for
dip-tube system conventional according to spray can the invention
Resin (solid) 2 ml 2 ml Propellant 30 ml 8 ml Ethanol 50 ml 7 ml
Water 17 ml 3 ml Total content 100 ml 20 ml Concentration of resin
2% 10% Total flow rate of system 1 g/s 0.2 grams per second Flow
rate of resin 0.02 grams per second 0.02 grams per second Reduction
of propellant n.a. 73% Reduction of ethanol n.a. 86% Reduction of
water n.a. 82% Total content reduction n.a. 80% Flow rate reduction
n.a. 80% Active reduction n.a. none n.a. = non applicable, % = in
relation to conventional spray can composition
[0066] The atomizing apparatus of the present invention can use a
reduced amount of propellant and diluents to achieve the same flow
rate of active ingredients, such as in the case of solid resin and
when comparing flow rates of atomized formulations of hairsprays
atomized using either a conventional spray can or the apparatus
according to the invention. In other words, the apparatus according
to the invention for atomizing the liquid product produces a spray
of the active ingredients at the same rate while using a lower
total flow rate of liquid product plus propellant in combination
with a reduced amount of propellant per amount of active
ingredient.
[0067] The mass mean particle size is generally adjustable from 2
.mu.m to 100 .mu.m with the atomizing apparatus according to this
invention.
[0068] The advantages of the apparatus for atomizing a liquid
product according to the invention are that a very low total flow
rate can be used to spray concentrated, e.g. viscous fluids, with a
small amount of gaseous propellant. As examples for liquid fluids,
air fresheners, insecticides, hair sprays, body sprays, perfumes
and deodorants, colorant compositions, chemically active
compositions, lubricants or fuel can be formed to droplets. As a
high viscosity of the liquid product is no further an obstacle to
atomizing, at such low total flow rates the apparatus for atomizing
according to this invention nearly eliminates the need for volatile
organic compounds such as alcohols, butane or dimethylether as
diluents to be included into the liquid product for reducing its
viscosity.
[0069] Although the formation of small droplets from the liquid
product is achieved within the capillary tube which is fed by the
liquid product and propellant, an additional small nozzle, such as
a swirl chamber nozzle, may be provided at the exit port for
further decreasing the droplet size.
[0070] For regulating and actuating the apparatus according to the
invention, valves can be located at several positions. In one
embodiment, a central valve can be arranged on the capillary tube
between the exit port and the adjacent entry port in order to block
further movement of propellant and atomized liquid product towards
the exit port. However, this embodiment is disadvantageous in
respect of possible mixing of propellant and liquid product via the
connecting portion of the capillary tube, where liquid product is
separately stored from the propellant, such as for example in a
collapsible bag arranged within the propellant contained in a
canister.
[0071] As a further embodiment, two separate valves can be used to
block the pipe or tubings delivering liquid product and propellant
to the first and second entry ports, respectively. These two valves
can be actuated simultaneously or in such a manner that the valve
controlling the second entry port allows inflow of propellant
before, during and after liquid product is admitted into the
capillary tube.
[0072] Furthermore, valves may be used which meter the amount of
liquid and/or propellant so that for each actuation of the valves,
an adjustable amount is dispensed.
[0073] When employing the apparatus according to the invention, the
liquid product containing the active ingredient can be dispensed
with only a small amount or no diluent. Therefore, the liquid
product is highly concentrated and very small flow rates can be
achieved in comparison to conventional systems. As a consequence,
the liquid product can reach for example skin without a large
amount of diluents such as volatile organic compounds, resulting in
a dry feel of the atomized liquid product as only little or no
energy is necessary for the evaporation of volatile organic
compounds. When using the atomizing apparatus according to the
present invention, the flow rate of active ingredient, as defined,
with only small amounts of diluents necessary for dissolving or
dispersing the actual active ingredient, the flow rate of active
ingredient can remain at the same level as in conventional systems,
however, using a greatly reduced total flow rate of propellant and
the active ingredient combined.
[0074] The present invention uses pressures for the gaseous
propellant from 2 bar to 5 bar (200 kPa to 500 kPa), preferably 2
bar to 4 bar and even more preferably 2 bar to 3 bar.
[0075] The total flow rate within the capillary tube within which
atomization of liquid product takes place is restricted to the
range specified above. In order to scale up the total flow rate of
an apparatus for atomizing liquid product within a capillary tube a
plurality of capillary tubes may be used which are arranged in a
bundle, a row or in another way. Every capillary tube of such
plurality of capillary tubes may be supplied with liquid product to
be atomized and propellant taken from the same source respectively.
A few capillary tubes for atomizing liquid product may be supplied
with several different liquid products and the same propellant or
several propellants taken from the same source or different
sources. In this case the liquid products come into contact with
each other after the single liquid product has been atomized. The
liquid product to be atomized and the propellant may be taken out
of containers having relatively small volumes which are combined
with preferably one or a few capillary tubes. This arrangement may
result in a handheld unit.
[0076] Furthermore, the liquid product to be atomized and the
propellant may be taken out of containers having relatively large
volumes or may be taken out of pipelines. These pipelines are
preferably connected to a plurality of capillary tubes. In this
case a continuous or quasi continuous operation of the atomizer is
possible. This arrangement may result in a stationary or mobile
unit for continuous or quasi continuous atomization of liquid
product. The total flow rate of such a unit is appreciably greater
than the total flow rate through only one of the single capillary
tubes.
[0077] The present invention will now be described in greater
detail with reference to the embodiments of the invention described
in the figures. Identical reference numbers refer to respective
parts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0078] The figures merely represent possible embodiments of the
present invention. The figures are not intended to limit the
invention to any of the preferred embodiments described in the
drawings. They show:
[0079] FIG. 1 is a graphical representation of the experimental
results described in Tables 3A and 3B, according to an embodiment
of the invention.
[0080] FIG. 2 shows an exemplary atomizing apparatus according to
an embodiment of the invention.
[0081] FIG. 3 shows an exemplary atomizing apparatus according to
an embodiment of the invention.
[0082] FIG. 4 shows a section of the capillary tube used in an
exemplary atomizing apparatus according to an embodiment of the
invention.
[0083] FIG. 5 shows a capillary tube used in an exemplary atomizing
apparatus according to an embodiment of the invention.
[0084] FIGS. 6, 7, 8 and 9 show different arrangements of flow
restrictors for use in an exemplary atomizing apparatus according
to an embodiment of the invention.
[0085] FIG. 10 shows an exemplary atomizing apparatus in the
inactive state, according to an embodiment of the invention.
[0086] FIG. 11 shows the active state of the same exemplary
atomizing apparatus as that in FIG. 10.
[0087] FIG. 12 shows yet another exemplary atomizing apparatus
according to an embodiment of the invention.
[0088] FIGS. 13, 14, 15, 16 and 17 show embodiments of the
atomizing apparatus according to the present invention, each having
small volume cavities.
[0089] FIG. 13 shows an embodiment that is applicable, for example
to a dip-tube system using liquefied gas as the propellant.
[0090] FIGS. 14, 15, 16, 17 and 18 show exemplary embodiments of
the present invention that are applicable, for example, for use in
a "bag-on-valve" type spray can system.
[0091] FIG. 19 shows an exemplary "bag-on-valve" type arrangement
of an atomizing apparatus according to an embodiment of the
invention.
[0092] The following list of reference numbers identifies examples
of some of the structures discussed in the figures and in the
detailed description of the embodiments.
[0093] List of reference numbers
[0094] canister
[0095] propellant
[0096] flexible bag
[0097] capillary tube
[0098] exit port of capillary tube
[0099] liquefied gas
[0100] liquid product
[0101] valve
[0102] valve
[0103] bore
[0104] flow restrictor
[0105] inner passageway
[0106] first entry port
[0107] second entry port
[0108] common entry port
[0109] valve arrangement
[0110] valve arrangement
[0111] bore
[0112] cavity
[0113] afferent tubing
[0114] cover
[0115] sealing ring
[0116] housing
[0117] gasket
[0118] stem
[0119] coil spring
[0120] transverse bore
[0121] afferent bore
[0122] sealing
[0123] gasket
[0124] space
[0125] flexible partition wall
[0126] chamber
[0127] chamber
[0128] lateral bore
[0129] connecting bore
[0130] connecting bore
DETAILED DESCRIPTION OF THE INVENTION
[0131] FIG. 1 is a graphical representation of the experimental
results described in Tables 3A and 3B.
[0132] For clarity of demonstration the following FIGS. 2 through
19 show embodiments of the apparatus according to the invention for
atomizing liquid product. In one embodiment of the present
invention, in which the pressure of a gaseous propellant is used to
atomize the liquid product, only a single capillary tube is used
within which the liquid product is atomized. Not shown in the
figures are embodiments of the present invention that employ a
plurality of capillary tubes within each of which atomization of
liquid product takes place.
[0133] FIG. 2 schematically shows a first embodiment of the
apparatus of the present invention, in which a canister 1 contains
a propellant 2. A flexible bag 3, arranged within the canister 1,
contains the liquid product 7 and is pressured by the propellant 2.
The flexible bag 3 is connected to the capillary tube 4 via valve
8, which in this case also allows the entry of propellant into the
capillary tube 4. The capillary tube 4 is open to the environment
at its exit port 5.
[0134] In FIG. 3, showing a further embodiment of the apparatus
according to FIG. 2, liquefied gas 6 is contained within the
canister 1 from which a propellant 2 is formed.
[0135] FIG. 4 shows a section of the capillary tube used for
atomizing the liquid product according to the invention. The
capillary tube 4 has an inner passageway 12, which is open to the
environment at the exit port 5. Entry ports 13, 14, used as first
and second entry ports, respectively or vice versa, allow the entry
of liquid product and propellant into passageway 12. At entry port
13, a flow restrictor 11 is shown. When the on/off valve 9 is open,
liquid enters to the entry port 13 within the restrictor 11 and
passageway 12. The gaseous propellant enters at entry port 14. The
pressure difference towards exit port 5 drives liquid product and
gaseous propellant through the capillary tube, which causes the
atomization of the liquid product inside the capillary tube. In
case a canister is used to store liquid product and propellant,
both are at the same pressure.
[0136] FIG. 5 shows a capillary tube 4, in which a common entry
port 15 is used for allowing the entrance of propellant and liquid
product in admixture.
[0137] FIGS. 6, 7, 8 and 9 show different arrangements of flow
restrictors 11 and valve 9 to control the flow rates of propellant,
liquid product and their admixture, respectively. Flow restrictors
11 and valves 9 can be arranged at different positions within the
pathway for liquid product, propellant and their admixture, before
or after the entry into the capillary tube 4.
[0138] FIGS. 10 and 11 show a canister 1 with the attached
atomizing apparatus according to the present invention. A flexible
bag 3 is connected to the capillary tube 4 via a bore 10 as an
afferent pathway allowing the entry of liquid product from the
flexible bag 3 into the first entry port 13, which is guarded by
valve arrangement 16. Propellant is admitted to the second entry
port 14 via bore 18 as a second afferent pathway, allowing entry of
propellant into the capillary tube via the second entry port 14,
which is guarded by the valve arrangement 17. When pushing (arrow)
the capillary tube 4 axially into canister 1, valve arrangements 17
and 16 are opened for dispensing liquid product, being atomized
within the capillary tube and being propelled by propellant through
exit port 5. The valve arrangements 16 and 17 may comprise an
annular seal such as an O-ring. FIG. 10 shows the apparatus in the
inactive state, FIG. 11 shows the same apparatus in the active
state. It is noted that this embodiment avoids any cavity for the
admixture of product and propellant.
[0139] FIG. 12 shows a similar arrangement to that of FIG. 10, but
using a capillary tube 4 which is closed at its axial end opposite
to the exit port 5 and has one common lateral entry port 15. The
gaseous propellant 2 mixes with liquid product 7 after passing bore
18. There is no separate valve arrangement for regulating the
inflow of liquid product into the capillary tube 4, however, valve
arrangement 17 regulates the inflow of the mixture of gaseous
propellant and liquid product into capillary tube 4 via annular
cavity 19.
[0140] FIGS. 13 through 19 demonstrate embodiments of the atomizing
apparatus, wherein cavity 19, arranged between afferent pathway 20
and the capillary tube 4, is dimensioned to have small volume.
[0141] FIG. 13 shows an exemplary atomizing apparatus according to
an embodiment of the invention that is applicable, for example, in
a dip-tube system using liquefied gas as the propellant. A cover or
lid 21 can be seen for fastening to a gas-tight canister with a
sealing ring 22. Housing 23 for a valve is threaded into a threaded
bore of cover 21 and sealed by a gasket 24 to cover 21. The gasket
24 engages an annular groove of stem 25 extending outwardly through
a bore of cover 21 and inwardly into the inner space of housing 23.
Coil spring 26 biases the stem 25 upwardly against gasket 24. The
stem 25 contains the capillary tube 4, having a small inner
diameter. At the lower end of capillary tube 4, a transverse bore
27 in stem 25 is provided, which is closed by gasket 24 when coil
spring 26 is in its extended state. The transverse bore 27 acts as
common entry port 15, however, a transverse second bore 27 may be
provided. The afferent tubing 20 is formed by a pipe which extends
through an eccentric bore of the housing 23 into cavity 19.
[0142] This embodiment is suitable for so-called dip-tube systems,
in which the propellant (for example, liquefied natural gas,
optionally chlorinated or fluorinated) forms a liquid mixture with
the liquid product and is guided as one mixture through the
afferent tubing 20. In order to keep the volume of cavity 19 small,
it is preferred that there is little or no connection to the space
in which coil spring 26 is arranged. In other words, the inner part
of stem 25 essentially seals the bore of housing 23, where coil
spring 26 is contained.
[0143] In FIG. 14 an embodiment of the invention is shown with a
cover 21 which can be fastened to a conventional metal can (not
shown) which is used for conventional spray packs. The housing 23
is fixed within the dome of the housing 23 and supports the
afferent tubing 20. The upper part of the housing 23 contains a
coil spring 26, which urges the lower part of stem 25 against
sealing gasket 24, which in turn engages an annular groove of stem
25. Gasket 24 seals lateral bore 18 in the upper portion of the
stem, which is connected with an elongated passage, which axially
continues into capillary tube 4. The lower portion of the housing
23 has an afferent bore 28, which is connected to cavity 19,
separated from the bore 18 by the gasket 24. Afferent bore 28,
being positioned higher than the opening of afferent tubing 20 as
suitable for admitting gaseous propellant into cavity 19, whereas
afferent tubing 20 allows the entry of liquid product into the room
occupied by coil spring 26 and, through an intermediate space
between the bore of housing 23 and stem 25 into cavity 19. When
stem 25 is pushed axially to compress coil spring 26, gasket 24 is
no longer positioned to seal bore 18, now admitting the mixture of
gaseous propellant and liquid product, formed in cavity 19, into
capillary tube 4. Such an embodiment is suitable for so-called
bag-on-valve type spray cans, in which the liquid product is
physically separated from the surrounding propellant by for example
a collapsible bag or a tube with movable piston, allowing
pressurization of liquid product by the pressurizing propellant.
The liquid product is only admitted into afferent tubing 20,
whereas the gaseous propellant only enters afferent bore 28.
However, such an embodiment may also be used in cases, where liquid
product and propellant are not separated by a physical barrier but
by phase-separation, for instance when the propellant is compressed
air or compressed nitrogen, which do not form a substantial liquid
phase and dissolves into the liquid product only to a small
amount.
[0144] In the embodiment illustrated in FIG. 14, both liquid
product and propellant are admitted via separate afferent tubings
to cavity 19, where they mix and enter the capillary tube 4 when
stem 25 is pushed so that gasket 24 opens the bore 18. The
embodiment illustrated in FIG. 15 differs from that shown in FIG.
14. In FIG. 15, afferent bore 28, admitting propellant, is formed
as an annular space between afferent tubing 20 and housing 23.
Afferent tubing 20 admits liquid product via connecting bores 36
and 37 to cavity 19. The sealing 29 prevents removal of afferent
tubing 20 and admixture of propellant and liquid product prior to
their entering cavity 19. The embodiment shown in FIG. 15 may be
used for the same applications as that of FIG. 14.
[0145] As an alternative embodiment, FIG. 16 shows afferent tubing
20 for liquid product and bore 28 for gaseous propellant,
respectively, before they are admitted to cavity 19. Cavity 19
opens into a lateral bore 18 when stem 25 is pushed axially for
removal from gasket 24 and further connects to capillary tube 4.
This embodiment may be used for the same applications as that of
FIG. 14.
[0146] In FIG. 17, liquid product is admitted by afferent tubing
20, which allows entry into the space occupied by coil spring 26
within housing 23. Gasket 30 seals the first entry port 13 and
gasket 24 seals the second entry port 14, when coil spring 26 urges
stem 25 in its extended state. Afferent bore 28 connects to an
annular space between housing 23 and stem 25 via lateral bore 18.
When pressing stem 25, second entry port 14 is opened by removal
from gasket 24, whereas first entry port 13 is opened by removal
from gasket 30 to allow gaseous propellant and liquid product,
respectively, to enter into space 31, which connects to the
capillary tube 4. In an upright position, however, space 31 is
filled with liquid product and a cavity 19 forms at the top end of
space 31 adjacent capillary 4. This embodiment is suitable for the
same purposes as the embodiment of FIG. 14.
[0147] In FIG. 18, afferent tubing 20 conducts liquid product into
a chamber 33, separated from chamber 34 by interposed flexible
partition wall 32. The flexible partition wall 32 is received in
annular grooves of stem 25 and housing 23, respectively, biasing
stem 25 against cover 21. Chamber 33 may connect to lateral bore 35
when gasket 24 is bent by depressing stem 25. Gaseous propellant is
admitted via lateral bore 28 into chamber 34, which connects to
bore 18 when gasket 24 is bent by the stem 25 being depressed.
Within space 31, corresponding to cavity 19, liquid product and
gaseous propellant are mixed before entering the capillary tube 4,
thus avoiding substantial cavities within the afferent pathway of
the mixture of liquid product and propellant before capillary tube
4. The embodiment of FIG. 18 may be used for the same purposes as
the embodiment according to FIG. 14.
[0148] FIG. 19 shows a "bag on valve" arrangement of the apparatus
according to the invention. The gaseous propellant enters through
afferent bore 28. The liquid product is stored in flexible bag 3
and enters through afferent tubing 20 discharging the liquid
product into cavity 19 where it is mixed with the gaseous
propellant. The mixture enters the capillary tube 4 via common
entry port 15.
[0149] In describing representative embodiments of the invention,
the specification may have presented the apparatus of the invention
and processes employing the liquid atomizing apparatus as a
particular combination of components. However, to the extent that
the apparatus or process does not rely on the particular
configuration as set forth herein, the apparatus and process of the
invention should not be limited to the order written, and skilled
in the art can readily appreciate that the components may be varied
and still remain within the spirit and scope of the invention.
[0150] The foregoing disclosure of the embodiments of the invention
has been presented for purposes of illustration and description. It
is not intended to be exhaustive or to limit the invention to the
precise forms disclosed. Many variations and modifications of the
embodiments described herein will be apparent to one of ordinary
skill in the art in light of the above disclosure. The scope of the
invention is to be defined only by the claims appended hereto, and
by their equivalents.
* * * * *