U.S. patent application number 11/642443 was filed with the patent office on 2007-07-12 for concentricity for long concentric nebulizers.
This patent application is currently assigned to Telegistics Inc.. Invention is credited to John A. Burgener.
Application Number | 20070158469 11/642443 |
Document ID | / |
Family ID | 38236315 |
Filed Date | 2007-07-12 |
United States Patent
Application |
20070158469 |
Kind Code |
A1 |
Burgener; John A. |
July 12, 2007 |
Concentricity for long concentric nebulizers
Abstract
A method for stabilizing and centrally positioning an inner
capillary in a concentric nebulizer comprises supporting the inner
capillary near the tip of the nebulizer by contacting the nebulizer
body against the inner capillary or by interposing a support
between the nebulizer body and the inner capillary near the tip. An
embodiment of a nebulizing device having stabilized central
positioning of its inner capillary is disclosed which comprises an
outer capillary with a linear bore and a gas/liquid orifice in a
distal tip, a central capillary disposed within the linear bore,
and a support sufficiently proximate the orifice to maintain the
central capillary substantially centered within the outer capillary
adjacent to the orifice. An open volume within the outer capillary
between the orifice and the support is dimensioned to enable gas
flow to spread substantially evenly around the central
capillary.
Inventors: |
Burgener; John A.;
(Mississauga, CA) |
Correspondence
Address: |
WEINGARTEN, SCHURGIN, GAGNEBIN & LEBOVICI LLP
TEN POST OFFICE SQUARE
BOSTON
MA
02109
US
|
Assignee: |
Telegistics Inc.
|
Family ID: |
38236315 |
Appl. No.: |
11/642443 |
Filed: |
December 20, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60757923 |
Jan 10, 2006 |
|
|
|
Current U.S.
Class: |
239/423 ;
239/398; 239/418 |
Current CPC
Class: |
B05B 7/0441 20130101;
B05B 7/045 20130101; F23D 11/10 20130101; B05B 7/0475 20130101 |
Class at
Publication: |
239/423 ;
239/398; 239/418 |
International
Class: |
F23D 11/10 20060101
F23D011/10 |
Claims
1. A method for maintaining the centricity of a central capillary
of a concentric nebulizer, comprising the steps of: providing a
concentric nebulizer outer capillary, which outer capillary
comprises a length, external and internal diameters, a bore, and an
inner wall, said outer capillary terminating at a tip and having an
orifice in said tip for gas and/or liquid, providing a first
central capillary having external and internal diameters disposed
within the outer capillary; and providing a support of the first
central capillary sufficiently near the orifice to maintain the
first central capillary centered within the outer capillary and
with respect to a center of the orifice.
2. The method of claim 1, further comprising providing a volume
intermediate the support of the central capillary and the orifice;
and providing at least one passage proximate the first central
capillary for allowing nebulizer gas to flow into the volume.
3. The method of claim 2, wherein the volume is large enough to
allow the gas flow to spread reasonably evenly around the first
central capillary before exiting the orifice.
4. The method of claim 1, further comprising inserting the support
about the first central capillary and within the outer capillary,
said support having a length and comprising a hub portion that has
an internal diameter approximately equal to the external diameter
of the first central capillary, and said support further
comprising, in cross-sectional aspect, a plurality of fins integral
with and extending radially from the hub region for contacting an
internal wall of the outer capillary, wherein each fin has a base
where the fin integrally connects with the hub portion and a tip
where the fin contacts the inner wall of the outer capillary along
a length of a support region.
5. The method of claim 4, further comprising providing fins having
a cross-sectional aspect tapering from relatively greater thickness
at their base to relatively lesser thickness at their tip.
6. The method of claim 1, further comprising providing disposed
inside the first central capillary a second central capillary,
terminating the first central capillary proximate the support, and
extending the second central capillary beyond the termination of
the first central capillary.
7. The method of claim 6, further comprising providing a third
central capillary disposed outside the first central capillary,
terminating the third central capillary on a side of the support
opposite the orifice, and extending the first central capillary
beyond the termination of the third central capillary.
8. The method of claim 1, further comprising forming or molding an
inner wall of the outer capillary such that the formed or molded
inner wall contacts the first central capillary in a support region
proximate to the orifice, wherein the step of providing a support
includes centrally supporting the first central capillary by
contact with the formed or molded outer capillary inner wall to
maintain the first central capillary centered within the outer
capillary adjacent to the orifice.
9. The method of claim 8, further comprising forming or molding the
inner wall of the outer capillary such that an open volume shaped
in cross-sectional aspect as an equilateral polygon is formed
within, and disposing the first central capillary, in
cross-sectional aspect, as an incircle of said polygon.
10. The method of claim 8, further comprising forming or molding
the inner wall into, in cross-sectional aspect, a plurality of
ridges projecting from the inner wall of the outer capillary for
supportably contacting the first central capillary, wherein each of
the ridges has a base where the ridge integrally connects with the
inner wall of the outer capillary and a tip for contacting the
outer surface of the first central capillary.
11. The method of claim 10 wherein each ridge runs the length of
the support region.
12. The method of claim 10, further comprising forming the inner
wall as a plurality of symmetrically disposed ridges in the support
region.
13. The method of claim 1, further comprising providing the bore in
the outer capillary dimensioned to receive the first central
capillary and to support the first central capillary along a
majority of its length centered in said outer capillary, and
providing a notch or notches along the outer surface of the first
central capillary and in fluid communication with the gas input to
allow gas to flow from a gas input to the gas/liquid orifice
through the notch or notches along said first central capillary
with minimal turbulence.
14. The method of claim 13, further comprising providing at least
one notch cut from the outer surface of the first central capillary
such that a cross-sectional profile of the first central capillary
comprises a circle from which a chord segment is removed.
15. The method of claim 1, wherein the step of providing a first
central capillary comprises providing a multilumen central
capillary having a central lumen for conveying a liquid flow and
having at least one non-central lumen for conveying a gas, and
wherein the step of providing an outer capillary comprises
providing the bore in the outer capillary dimensioned to receive
the multilumen central capillary and to support the multilumen
central capillary by contact along a majority of its length.
16. The method of claim 15, further comprising progressively
diminishing a radius of the first central capillary in a region
proximate the orifice such that the first central capillary
comprises only the central lumen adjacent the orifice.
17. The method of claim 1, further comprising providing a first
central capillary having a wall with a thickness, wherein the
thickness of the wall tapers without changing a diameter of a
central lumen contained within the first central capillary along a
distance from the support to a point adjacent the orifice, such
that at the termination of the first central capillary the external
diameter of the central capillary is substantially equal to the
diameter of the central lumen.
18. The method of claim 1, further comprising maintaining smooth
gas flow in the nebulizer by providing passages around, beside or
through said support for allowing the gas to flow past or through
the support with minimal turbulence and by providing an open volume
near the gas orifice, which volume is large enough to allow the gas
flow to spread substantially evenly around the central
capillary.
19. A nebulizing device comprising a nebulizer body with gas and
liquid inputs, an outer capillary having external and internal
diameters, a length, a wall, an inner wall surface defining a bore
and a distal tip, a substantially linear, cylindrical, first
central capillary disposed within the bore, said first central
capillary having an external diameter and an outer surface; at
least one lumen within the first central capillary; a gas/liquid
orifice in the tip of the outer capillary; a support positioned in
a support region sufficiently proximate the orifice to maintain the
first central capillary substantially centered within the outer
capillary adjacent to the orifice; and an open volume within the
outer capillary intermediate the orifice and the support
dimensioned to allow the gas flow to spread substantially evenly
around the first central capillary.
20. The nebulizing device of claim 19, further comprising passages
around, beside or through said support for allowing gas to flow
past or through the support region with minimal turbulence.
21. The nebulizing device of claim 19, wherein the support
comprises a hub portion having an internal diameter approximately
equal to the external diameter of the first central capillary, and,
in cross-sectional aspect, a plurality of fins integral with and
extending radially from the hub region to contact the inner wall
surface of the outer capillary, the support being inserted around
the first central capillary and within the outer capillary; wherein
each fin has a base where the fin integrally connects with the hub
portion and a tip where the fin contacts the inner wall surface of
the outer capillary along a length of the support region.
22. The nebulizing device of claim 21, wherein each fin tapers in
thickness from relatively greater thickness at its base to
relatively lesser thickness at its tip.
23. The nebulizing device of claim 19, further comprising a second
central capillary disposed within the first central capillary, the
first central capillary being supported by and terminating
proximate the support, and the second central capillary extending
beyond the termination of the first central capillary substantially
through the volume and terminating adjacent the orifice.
24. The nebulizing device of claim 23, further comprising a third
central capillary disposed outside the first central capillary and
terminating on a side of the support opposite the orifice and being
not directly supported by the support.
25. The nebulizing device of claim 19, wherein the outer capillary
has an inner wall formed or molded to contact and centrally support
the first central capillary along the length of a support region,
wherein the support maintains the first central capillary centered
within the outer capillary adjacent to the orifice.
26. The nebulizing device of claim 25, wherein the inner wall in
cross-section is formed as an equilateral polygon, and inside the
polygon, the external diameter of the first central capillary, in
cross-section, forms an incircle.
27. The nebulizing device of claim 25, wherein the support
comprises, in cross-section, a plurality of ridges projecting
integrally from the inner wall surface of the outer capillary to
contact the first central capillary, wherein at least one ridge of
the plurality of ridges has a base wherein the ridge is integrally
connected with the inner wall surface of the outer capillary and a
tip where the ridge contacts the outer surface of the first central
capillary.
28. The nebulizing device of claim 27, wherein each ridge runs the
length of the support region.
29. The nebulizing device of claim 27, wherein the plurality of
ridges are symmetrically disposed in the support region.
30. The nebulizing device of claim 19, wherein the bore in the
outer capillary is dimensioned to receive said first central
capillary and to support the first central capillary by contact
along a majority of its length, wherein the first central capillary
is maintained centered within the outer capillary adjacent to the
orifice; at least one notch is cut along the outer surface of the
first central capillary and are in fluid communication with the gas
input and the open volume, such that gas can flow from the gas
input to the open volume and thereby to the gas/liquid orifice
through the at least one notch along said first central capillary
with minimal turbulence; and the support positioned about the first
central capillary is continued sufficiently close to the orifice to
maintain the first central capillary centered within the outer
capillary proximate the center of the orifice.
31. The nebulizing device of claim 30, wherein the at least one
notch is cut from the outer surface of the first central capillary
such that a cross-sectional profile of the first central capillary
comprises a circle from which a chord segment is removed.
32. The nebulizing device of claim 19, wherein the first central
capillary comprises a multilumen central capillary having a central
lumen for conveying a liquid flow and at least one non-central
lumen for conveying a gas flow; and the bore in said outer
capillary is dimensioned to receive and to support said multilumen
capillary by contact along a majority of its length.
33. The nebulizing device of claim 32, wherein a radius of the
multilumen capillary diminishes toward the orifice such that the
multilumen capillary comprises only the central lumen proximate and
after the end of the support region.
34. The nebulizing device of claim 19, wherein the first central
capillary has a wall having a thickness, wherein the thickness of
the wall tapers without changing a diameter of the lumen contained
within the first central capillary along a distance from the
support to a point adjacent the orifice, such that at the
termination of the first central capillary the external diameter of
the first central capillary is substantially equal to the diameter
of the lumen.
35. The nebulizing device of claim 19, wherein the support is
located entirely in a half of the outer capillary that contains the
orifice.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C.
.sctn.119(e) to U.S. Prov. Pat. Appl. No. 60/757,923 filed Jan. 10,
2006, the disclosure of which is incorporated herein by
reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] N/A
BACKGROUND OF THE INVENTION
[0003] Concentric nebulizers have been in use for over 100 years as
furnace burners, paint spray guns, medical nebulizers, analytical
nebulizers and for many other uses. Concentric nebulizers have a
central capillary that usually carries the liquid, and an outer
capillary that surrounds the central capillary and usually carries
the gas. As gas flows out of the outer capillary, it sucks the
liquid out of the inner capillary and creates an aerosol. Ideally,
the inner capillary should be perfectly centered in the outer
capillary to provide the best gas flow around the inner capillary
and produce the best mist.
[0004] There are many variations of concentric nebulizers, each
developed according to its purpose. But many designs require that
the concentric nebulizer should be much longer than wider on the
end where the atomized liquid is sprayed out.
[0005] The efficiency of the nebulizer relates to many factors such
as the gas pressures, gas flow rates, liquid flow rates, liquid
viscosity, and others. One factor that is often difficult to deal
with is how closely the central capillary sits in the center of the
gas orifice in the end of the outer capillary. This is a factor
that has a large influence on the consistency of the aerosol
produced. Due to the difficulty of holding the central capillary
perfectly centered, it is rare that it is actually centered in
commercially available concentric nebulizers.
[0006] When the central capillary is not concentric, then there
will be more gas flow on one side of the gas orifice than on the
other side. This will lead to turbulence which will produce larger
droplets than occurs with non-turbulent flow. In most applications,
smaller droplets are desired.
[0007] Analytical concentric nebulizers used in Inductively Coupled
Plasma (ICP) and IC/Mass-Spectroscopy (MS) spectrometers are
particularly effected by such non-concentricity, as their aerosols
must be consistent from one nebulizer to another, and the
sensitivity of the spectrometer depends largely on the droplet
sizes produced by the nebulizer.
[0008] Analytical concentric nebulizers are available from many
sources, and are usually made of glass or inert plastics. Due to
historical reasons, most analytical nebulizers are made with a long
front cylindrical section approximately 6 mm in outside diameter
and about 25 mm long, and a back section of various sizes and
configurations to attach the liquid and gas lines. This allows the
nebulizers to fit most spectrometers without requiring special
adapters. There is no other intrinsic reason for the sizes to be
used, but the present art is such that most or all are made with
this front size and shape. It is desirable to continue using the
standard sizes in future designs to allow easy usage of the
nebulizers in present systems. It is also desirable to enable
concentric nebulizers used for other purposes to be able to have
very long bodies while maintaining the central capillary as close
as possible to the exact center of the gas orifice.
[0009] The present art for analytical nebulizers uses glass
blowing, molding and machining techniques to make the nebulizers.
They are commonly made of glass, plastic, or non-corrosive
materials such as stainless steel. In all present commercially
available designs, the inner capillary is attached in the middle or
at the back of the nebulizer body and extends forward to the tip of
the nebulizer. The strength of the material of the inner capillary
is all that holds the inner capillary in place in the center of the
outer capillary. In most cases, the inner capillary does not get
positioned in the center of the outer capillary as the material is
not strong enough to hold the tiny inner capillary exactly in
place. In many designs, the inner capillary will vibrate as the gas
flows around it, further effecting the quality of the mist.
[0010] FIG. 1 and FIG. 2 show cross-sections of glass concentric
nebulizer designs that are presently commercially available for
analytical usage. For both, there is a liquid sample entry section
103; a connecting point 105 of the central capillary 109 to the
main body of the nebulizer; an outer tube portion (outer capillary)
107 that carries the gas flow and comprises the nose of the
nebulizer, an inner, central lumen within the central capillary 109
that carries the liquid to the gas orifice at the nebulizer tip
111; and a gas inlet 113 which is typically designed as a barb
fitting or as a threaded fitting for the gas input lines. FIG. 1
shows a glass blown design in which the inner capillary 109 is
thick at the junction point 105, and very narrow from there to the
tip 111. The thin glass tube is very fragile and easy to break. It
is also difficult for the central glass tube to remain positioned
in the center of the tip. It usually leans to one side in the tip.
FIG. 2 shows a glass nebulizer with the inner central capillary 109
ground to a conical shape. This provides a stronger support for the
central capillary, but still is not strong enough to keep the
capillary 109 centrally placed close to the nebulizer tip 111.
[0011] FIG. 3 shows a cross-section of a molded nebulizer presently
available for analytical usage. This is a plastic molded design in
which a central capillary is made of three separate concentric
capillaries, a first central capillary 109, a second central inner
capillary 112, and a third central inner capillary 123. This
provides more support at the base (connecting junction) 105.
However, the innermost capillary 123 is very thin and very soft,
and often bends away from the tip 111, producing a very poor
mist.
[0012] In standard analytical nebulizers, the common practice is to
make the nebulizer with a 6 mm OD nose (outer capillary) that is
about 25 mm long. With such a long, thin nose, the central liquid
passage has been typically very long and very thin, and not rigidly
held in place.
[0013] It is apparent that the diameter and the unsupported length
of the central capillary are critical to determine its strength and
ability to be held correctly in the center. If analytical
nebulizers were made with a short, thick central capillary, then
the mist produced would be more consistent and the nebulizer much
less likely to break. However, standardization in equipment
receiving nebulizers has resulted in the less optimal long, thin
form factor.
[0014] Long concentric nebulizers typically are manufactured with
long, unsupported, central capillaries. The central capillaries
often vibrate during use, causing irregularities in the mist
produced. Owing to their length, the central capillaries often
break very easily. Should any particle become lodged in the central
capillary, it is usually impossible to remove the particle without
breaking the central capillary due to the fragility of the central
capillary.
BRIEF SUMMARY OF THE INVENTION
[0015] The present invention allows the production of concentric
nebulizers with better central positioning of an inner central
capillary within the nebulizer with minimal complicating factors in
the design.
[0016] The present invention provides a process and apparatus for
stabilizing the central positioning of an inner capillary of
concentric nebulizers, optionally along the entire length of the
inner capillary but necessarily near the tip of the outer capillary
(i.e., near the tip of the nebulizer). This allows the inner
central capillary to be more exactly centered in a gas orifice at
the tip of the nebulizer, and it dramatically decreases any
vibrations in the inner capillary as the gas flows through the
outer capillary.
[0017] One embodiment of the present method comprises the steps of
providing: a body to hold outer and inner capillaries including
means to attach gas and liquid supplies to the device, a passage to
convey a gas stream, an inner capillary to convey a liquid, and a
support in the body near the tip of the nebulizer to hold the inner
capillary more centered.
[0018] A further embodiment of the invention provides a method for
maintaining the centricity of a central capillary of a concentric
nebulizer, comprising the steps of providing a concentric nebulizer
having an outer capillary, which outer capillary comprises a
length, external and internal diameters, a bore, and an inner wall,
said outer capillary terminating at a tip and having an orifice in
said tip for gas and/or liquid, providing at least one central
capillary having external and internal diameters disposed within
the outer capillary; and providing a support of the at least one
central capillary sufficiently near the orifice to maintain the
central capillary centered within the outer capillary and with
respect to a center of the orifice.
[0019] The support for an inner member comprising a central
capillary may be of many various styles and shapes. The support may
be in the form of an inner member comprises a central capillary in
contact with the nebulizer body near the tip of the nebulizer, or
the support may comprise an additional support element interposed
between the body of the nebulizer and an inner member comprising a
central capillary. The essence is simply that the inner capillary
should be supported very close to the nebulizer tip rather than
from the back or middle part of the nebulizer body. It can be
advantageous to make the inner capillary of larger outside diameter
than presently is standard, to allow some portion of the inner
capillary to be securely positioned by the inner support. If the
inner capillary is too small in outer diameter, then the support
may not work as well.
[0020] In one embodiment of the invention, a preferred method of
support is to have the inner central capillary secured in the body
of the nebulizer for the majority of the nebulizer's length,
leaving only a small enough portion at the tip unsecured to allow
the gas to flow smoothly around the inner capillary as it leaves
the gas orifice.
[0021] A further embodiment of the invention provides for a
nebulizing device comprising a nebulizer body with gas and liquid
inputs, an outer capillary having external and internal diameters,
a length, a wall, an inner wall surface and a distal tip, a linear
bore through the outer capillary having a diameter; a substantially
linear, cylindrical, central capillary disposed within the linear
bore, said central capillary having an external diameter, an outer
surface and at least one substantially linear feature on the outer
surface thereof for conveying a gas flow; at least one lumen within
the central capillary; a gas/liquid orifice in the tip of the outer
capillary; a support positioned in a support region sufficiently
proximate the orifice to maintain the central capillary
substantially centered within the outer capillary adjacent to the
orifice; and an open volume within the outer capillary intermediate
the orifice and the support dimensioned to allow the gas flow to
spread substantially evenly around the central capillary.
[0022] The invention further provides for, within the outer
capillary of a nebulizer, a central capillary having a wall,
wherein the thickness of the wall tapers without changing a
diameter of a central lumen contained within the central capillary
along a distance from the support to a point adjacent the orifice,
such that at the termination of the central capillary the external
diameter of the central capillary is substantially equal to the
diameter of the central lumen.
[0023] One embodiment of the invention further provides for the
support is located entirely in a half of the outer capillary that
contains the gas orifice.
[0024] Other aspects, features and advantages of the present
invention are disclosed in the detailed description that
follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The invention will be more fully understood by reference to
the following detailed description of the invention in conjunction
with the drawings, of which:
[0026] FIGS. 1 and 2 illustrate conventional glass analytical
nebulizers currently in production;
[0027] FIG. 3 illustrates a conventional perfluoro-alkoxy (PFA),
copolymer-resin, analytical nebulizer currently in production;
[0028] FIG. 4A illustrates a concentric nebulizer according to an
embodiment of the invention with a support at the tip to help
center a central capillary;
[0029] FIG. 4B illustrates a similar design of support as
illustrated in FIG. 4A, but with a nebulizer body similar to that
illustrated in FIG. 3;
[0030] FIG. 5 illustrates a method of supporting a central
capillary by using a wider central capillary fully supported for
the majority of the length of the nebulizer, with either a notch in
the central capillary or additional holes in the central capillary
to convey the gas;
[0031] FIGS. 6A and 6B illustrate an insert supporting a first
inner central capillary with a smaller, second inner capillary
within the first inner central capillary;
[0032] FIGS. 7A and 7B illustrate an insert supporting the tip of a
central capillary that has been shaped to a point at its tip;
[0033] FIGS. 8A-8D illustrate a molded tip of the outer capillary
with a non-circular inner surface cross-section, enabling the
molded tip to center the central inner capillary while allowing the
gas to pass the capillary support;
[0034] FIGS. 9A and 9B illustrate a body similar to that
illustrated in FIG. 5 with a central capillary fully supported for
the majority of the length of the nebulizer, but with a notch on
one side to allow the gas to flow to the tip; and
[0035] FIGS. 10A and 10B illustrate a body similar to that
illustrated in FIG. 5 with a central capillary fully supported for
the majority of the length of the nebulizer, but with one or more
additional lumens in the central capillary tube to allow the gas to
flow to the tip.
DETAILED DESCRIPTION OF THE INVENTION
[0036] According to embodiments of the present invention, long
concentric nebulizers can be produced with better concentricity
than previously possible, which improves the aerosol produced.
[0037] It is one of the objectives of the presently disclosed
invention to provide for concentric nebulizers with an inner
capillary that is very long in length and that is well supported
and well held in line with the center of the exit hole of the
nebulizer.
[0038] The inner capillary can be firmly held centrally in place by
a support close to the tip of the nebulizer. However long the
nebulizer body is, if the central capillary is well supported,
especially at or proximate to the tip of the nebulizer, the tip of
the capillary can remain centered. The difficulty in providing
support along the length of the central capillary or at the tip of
the nebulizer is that the support must be able to allow the gas to
pass through it, or the nebulizer will not function. Further, the
gas must flow with minimal or no turbulence as it exits the tip of
the nebulizer. Turbulence in the gas flow would cause larger
droplets to be formed, degrading the mist.
[0039] FIGS. 4A and 4B show variations on how a support 15 can be
employed according to embodiments of the invention to improve the
support of the central, inner capillary. Support 15 can be provided
as an insert near the tip of the nebulizer or as a molded part of
the inside wall of the tip of the nebulizer.
[0040] Referring to FIG. 4A, one embodiment provides for a
nebulizer body with gas input 13 and liquid input 3, comprising a
back section 5 of various sizes and configurations to attach liquid
and gas lines and an outer nose portion 7 of the nebulizer (e.g., a
long, front cylindrical section, or outer capillary). This outer
portion 7 can have, inter alia, (a) an external diameter 28, (b) a
wall, (c) an inner wall surface, (d) a linear bore passing through
the outer portion, which bore has an internal diameter, and (e) a
distal tip. The nebulizing device of this preferred embodiment may
further comprise a substantially linear, cylindrical, inner member
9 disposed within the linear bore, said inner member 9 having an
external diameter, an outer surface and having at least one
substantially linear feature on the outer surface thereof for
conveying a gas flow. Said inner member 9 can comprise a first
inner, central capillary. In addition, a second inner capillary 12
may be formed within the inner member 9 for conveying a liquid
flow, and a gas/liquid orifice 11 may be located in the tip of the
outer nose portion 7 of the nebulizer body. In this preferred
embodiment of a nebulizer device according to the invention, a
support 15 exists in a support region sufficiently close to the
gas/liquid orifice 11 to maintain the second inner capillary 12
substantially centered in the outer nose portion close to the
orifice 11. Passages around, beside or through said support 15
exist to allow gas to flow past or through the support region with
minimal turbulence, and an open volume 17 exists within the outer
portion near the orifice 11, said volume dimensioned to allow the
gas flow to spread reasonably evenly around the inner member 9 and
second inner capillary 12.
[0041] The invention, as depicted in FIG. 4A, also provides further
for a device wherein a first inner central capillary 9 is supported
by and terminates closely after the support 15, and a second inner
central capillary 12 extends beyond the termination of the first
central capillary 9 substantially through the volume 17 to
terminate near the orifice 11. One exemplary embodiment provides,
measured at a cross-section within the first half of the support 15
away from the orifice 11, an inner member 9 having an external
diameter of about 2 mm and disposed within said inner member 9 a
secondary inner capillary 12 having external diameter about 0.5 mm
or less and having an inner diameter about 0.25 mm or less.
[0042] In another embodiment, shown in FIG. 4B, the first central
capillary 9 contains a secondary inner capillary 12, which extends
beyond the termination of the first central capillary 9
substantially through the open volume 17 such that the secondary
inner capillary 12 is centered within the outer nose portion 7 and
terminates close to the gas/liquid orifice 11. A third central
capillary 23 can be disposed outside the first central capillary 9
and can terminate before the support 15 and is not directly
supported by the support 15, but the first central capillary 9 is
supported directly by the support 15 and terminates close after the
support.
[0043] Referring still to FIG. 4B, a further exemplary embodiment
provides, measured at a cross-section at the beginning end of the
outer nose portion 7 away from the end containing the orifice 11,
an inner member (or third inner central capillary) 23 having an
external diameter about 3.0 mm, wherein disposed within the inner
member 23 is a first central capillary 9 having an external
diameter about 2.0 mm, and disposed within said first central
capillary 9 is a secondary inner capillary 12 having an external
diameter about 0.5 mm or less and having an inner diameter about
0.25 mm or less.
[0044] A further preferred embodiment, referring still to FIGS. 4A
and 4B provides for a nebulizer having a support 15 and a supported
region 75. In these examples, the support 15 is positioned entirely
in the end of the outer nose portion 7 of the nebulizer that
contains the orifice 11.
[0045] FIGS. 5 and 9A illustrate how a bore can be provided in said
nebulizer body dimensioned to receive a central capillary 9 and to
support the capillary 9 along a majority of its length centered in
said outer portion 7. If the central capillary has a linear notch
along one side, such as notch 19 shown in FIG. 5, the central
capillary 9 will be supported by the inner wall of bore 10, and the
notch will allow the gas to flow to the tip of the nebulizer. In
this example, at least one notch 19 is provided along the outer
surface of the central capillary and in communication with the gas
input 13 to allow gas to flow from the gas input 13 to the
gas/liquid orifice 11 through the at least one notch 19 along the
capillary with minimal turbulence. The central capillary 9 is
supported by the bore sufficiently close to the orifice 11 to
maintain the central capillary centered within the outer portion 7
close to the center of said orifice 11. An expansion space, or open
volume 17, can be provided close before the orifice 11.
[0046] To allow a non-turbulent gas flow, a support must have
sufficiently large holes or other pathways in it for the gas to
pass through smoothly. Also, the support must leave some room (open
volume) at the tip of the nebulizer to allow the gas flow to spread
evenly around the central capillary. FIGS. 4A, 4B and 5 show open
volume 17 at the tip of the nebulizer. This open volume 17 must be
large enough to allow the flow of the gas to spread reasonably
evenly, and the length of this volume must be short enough to
maintain support for the central capillary 9. Exact sizes are
determined by the materials in use, inter alia.
[0047] In some exemplary embodiments of the invention, the outer
nose portion 7 of the nebulizer can have a length of about 20 to 40
mm and an external diameter about 6.0 mm.
[0048] As long as the cross-sectional space for the gas flow within
the support 15 is enough and the final open volume 17 around the
terminating tip of the inner capillary 9 is large enough, then the
gas flow will remain sufficiently non-turbulent.
[0049] FIGS. 6A and 6B illustrate one embodiment that provides for
a support 15 with a cross-section similar to a bicycle wheel, i.e.,
with radial spokes. The spokes are formed of longitudinal fins or
vanes, which extend from the outer surface of the central
capillary, or from a support hub surrounding the capillary, to the
inner surface of the outer capillary 7. FIG. 6A is an expanded
detail view of the tip end of an outer capillary 7 with a support
15 holding a first inner central capillary 9, where inside the
first inner capillary 9 is disposed a second inner capillary 12.
The first inner capillary 9 is supported by the support 15
proximate to the terminating tip of the inner capillary 9, and the
smaller second inner capillary 12 extends through the short open
volume 17 to the nebulizer tip 11. This minimizes the volume
occupied by the capillaries within the open volume 17, thus
facilitating the spread of gas flow. FIG. 6B shows a cross-section
of FIG. 6A along line 6B-6B, where the cross-section of support 15
is similar to spokes of a bicycle wheel, but with proportionally
thicker fin-like supports 16.
[0050] FIGS. 7A and 7B show a cross-sectional support similar to
that illustrated in FIG. 6A and 6B, but with a different style of
central capillary 9. In FIG. 7A, the central capillary 9 is made of
a thicker outside dimension and has a tapered tip. The thickness of
the central capillary wall tapers without changing the diameter of
its lumen or of a secondary inner capillary disposed inside said
central capillary 9. In one embodiment, this taper can occur along
a distance from the support 15 to the gas orifice 11, such that at
the termination of the inner member 9 near the orifice 11 the wall
of the inner member 9 is almost a knife-edge and at the termination
point the external diameter of the central capillary 9 is
substantially equal to the diameter of its lumen or of a secondary
inner capillary. At least a portion of the non-tapered part
proximate to the nebulizer tip 11 is supported and the tapered part
extends the short distance past the support 15 to the tip 11.
[0051] Shown in FIG. 7A, wherein the outer portion 7 has an
external diameter 28 and an internal wall 4, a support 15 can be
inserted about the central capillary and within the outer portion
7, said support 15 having a length and comprising a hub portion 26
that in cross-sectional aspect has an internal diameter
approximately equal to the external diameter of the central
capillary 9, and said support further comprising, in cross-section,
a plurality of fins 16 integral with and extending spoke-like from
the hub portion 26 to contact the internal wall of the outer
portion 7 of the nebulizer, wherein each fin 16 has a base where
the fin integrally connects with the hub portion 26 and a tip where
the fin 16 contacts the inner wall 4 of the outer portion 7 of the
nebulizer.
[0052] With reference to FIG. 6A, a further exemplary embodiment
provides, measured at a cross-section within that half of the
support 15 away from the orifice 11, a first inner capillary 9
having an external diameter 14 of about 2.0 mm. Disposed within the
first inner capillary 9 is a second inner capillary 12 having an
inner diameter of about 0.5 mm or less.
[0053] With reference to FIG. 7A, another exemplary embodiment
provides, measured at a cross-section within that half of the
support 15 away from the orifice 11, an inner capillary 9 having an
external diameter of about 2.0 mm. However, as one moves along the
inner capillary 9 toward the gas orifice 11, the outer diameter of
the inner capillary 9 becomes progressively smaller.
[0054] In both FIGS. 6B and 7B, the support is shown in
cross-section with ten fins 16. The number and thickness of fins 16
in the support 15 is not critical. The critical aspect is that the
gas flows with minimal turbulence and at a desired rate. The open
space of the cross-sectional shape of the support 15 can be varied
depending on the flow rates intended to be used in the operation of
the nebulizer.
[0055] As shown in FIG. 7B, the fins 16 can have a cross-sectional
aspect tapering from relatively greater thickness at their base to
relatively lesser thickness at their tip.
[0056] FIGS. 8A, 8B, 8C and 8D show different cross-sections, more
appropriate for a molded support. FIG. 8A shows how a molded
support 15 can be included as part of a molded tip of a nebulizer,
with the central capillary 9 pressed into the support. The inner
wall 4 of the outer capillary 7 of the nebulizer can be formed or
molded such that the formed or molded wall contacts the inner
central capillary 9 in a support region 75 close to the orifice 11.
The capillary 9 is centrally supported by contact with the molded
inner wall of the outer capillary 7 to maintain the inner central
capillary 9 centered within the outer capillary 7 close to the
orifice 11.
[0057] FIGS. 8B, 8C and 8D show various configurations of
cross-sections that could be used as a support 15. In all of the
configurations shown, there are differences in the cross-sectional
area allowed for the gas flow in the support region, so some
configurations would be more appropriate for lower gas flows and
some for higher gas flows. Referring to FIG. 8B, the inner wall 4
of the outer portion 7 can be formed such that, in cross-section,
an open volume shaped as an equilateral polygon, such as, for
example, a triangle, is formed within the inner wall 4, and the
inner capillary can be disposed, in cross-section, as an incircle
of said polygon.
[0058] In another embodiment, as shown in FIGS. 8C and 8D, the
inner wall can be formed into, in cross-section, a plurality of
ridges 30 that project from the inner wall of the outer portion to
contact the inner member 9, wherein each of the ridges has a base
where the ridge integrally connects with the inner wall of the
outer portion and a tip where the ridge contacts the outer surface
of the inner member 9, and each ridge runs the length of the
support region 75 (see FIG. 8A). The support region 75 formed by
the molded inner wall can be three ridges (see, for example, as in
FIG. 8C) or six ridges (see, for example, as in FIG. 8D) or any
other number of ridges symmetrically disposed about the inner
member.
[0059] Referring to FIGS. 8A, BB, 8C and 8D, one embodiment of the
invention provides, measured at a cross-section within that half of
the support 75 away from the orifice 11, an inner member 9 having
an external diameter of about 2 mm, and disposed within the inner
member a secondary inner capillary having an inner diameter of
about 0.5 mm or less.
[0060] FIGS. 9A and 9B show details and cross-sections of a
nebulizer tip 11 similar to the tip 11 shown in FIG. 5. In FIG. 9A,
one embodiment provides for a central capillary 9 that has been
inserted into a bore extending through the nebulizer. The central
capillary 9 may be glued or press-fit at the back where the liquid
input is provided, to prevent the gas from exiting at the liquid
input. The central capillary 9 has at least one notch 19 cut from
the outer surface of a central capillary 9 such that a
cross-sectional profile of the capillary 9 comprises a circle from
which a chord segment notch 19 is removed (see FIG. 9B). In one
embodiment, said chord segment notch 19 is, at its thickest point,
about 4% to 5% of the outer portion external diameter 28.
Alternatively, the central capillary 9 may have more than one notch
19, as long as enough of the capillary 9 remains to be properly
supported by the inner walls of the bore 10. The notch or notches
19 will extend from the gas input to the terminating tip of the
capillary 9, and not all the way back to the liquid input area. The
central capillary 9 and bore 10 extending through the nebulizer can
each be of a non-circular shape, so long as the central capillary 9
remains supported.
[0061] As shown in FIGS. 10A and 10B, an extruded multilumen
central capillary 20 can comprise the inner member with a central
lumen 22 and at least one non-central lumen 24. The multilumen
capillary 20 is a capillary with several holes running along its
length rather than one hole in the center. A liquid flow can be
conveyed in the central lumen 22 and a gas flow can be conveyed in
the at least one non-central lumen 24, said at least one
non-central lumen 24 being sized to allow a desired volume of gas
to flow at a desired rate with minimal turbulence. If the central
extruded capillary 22 is tapered at the tip, then the holes 24
conveying the gas will end before the tip of the nebulizer and
allow the gas to spread evenly around the central portion of the
capillary in open volume 17. To have the gas flow in the additional
holes 24 for the gas, the back portion of the gas holes must be
plugged and holes or notches must be provided in the sides of the
capillary to allow the gas to flow from the gas input of the body
into the holes 24 for the gas in the multilumen central capillary
20.
[0062] A bore 10 in said nebulizer body is dimensioned to closely
receive said central capillary 20 and to support the inner member
by contact along a majority of its length. The bore 10 supports the
capillary 20 centered in the bore sufficiently close to the
gas/liquid orifice 11 to maintain the central lumen 22 centered
within the outer portion 7 close to the center of said orifice 11.
In a further exemplary embodiment, the support of said bore is
continued along the length of the central capillary 20 to a point a
short distance from the orifice 11. Within the inner member 9 a
central lumen 22 can be provided and at least one non-central lumen
24 having relatively small diameters. The radius of the capillary
20 diminishes toward the nebulizer tip so that only a radius of the
inner member enclosing the central lumen 22 is remaining proximate
the orifice 11.
[0063] According to embodiments of the present invention, very long
nebulizers can be made if they have support for the central
capillary 9. The method shown in FIGS. 5, 9A and 10A are easily
adapted to unlimited length nebulizers--the support may extend for
the entire length of the inner central capillary 9. The capillary
can be any length desired, as it is not dependent upon the
structural strength of the central capillary 9.
[0064] In other embodiments, as shown for example in FIGS. 4A and
6A a short unsupported length of the second inner capillary 12 (or,
as shown in FIG. 4B, of the third inner capillary 23) can extend
through the open volume 17 toward the orifice 11.
[0065] In one preferred embodiment, the nebulizer can have an outer
nose portion (i.e., the long, front cylindrical section, or the
outer capillary) that can have a length about 25 mm and an external
diameter about 6 mm, and a back section of various sizes and
configurations to attach the liquid and gas lines.
[0066] A method according to the present disclosure maintains
smooth gas flow in the nebulizer by providing passages around,
beside or through the support that allow the nebulizer gas to flow
past or through the support region with minimal turbulence and by
providing an open volume comprising a cross-sectional open area and
a length near the gas orifice, which volume is large enough to
allow the gas flow to spread substantially evenly around the inner
capillary near the gas orifice.
[0067] The foregoing discussion, for convenience, has referred to
gas flowing in the outer capillary and liquid flowing in the inner
central capillary (and/or through secondary or tertiary inner
central capillaries); however, the same advantages of the invention
can be observed in nebulizers in which the gas and liquid flows are
switched. The gas may be conveyed in the inner central capillary
and the liquid in the outer capillary, although it is more common
and more efficient to have the gas outside (flowing within the
outer capillary) and the liquid in the center (flowing within the
inner capillary).
[0068] While the invention has been described in connection with
specific methods and apparatus, those skilled in the art will
recognize other equivalents to the specific embodiments herein.
These and other embodiments of the invention illustrated above are
intended by way of example and should not be viewed as limiting the
scope of the disclosure or of the claims. The actual scope of the
invention is to be limited solely by the scope and spirit of the
following claims.
* * * * *