U.S. patent number 3,762,409 [Application Number 05/086,525] was granted by the patent office on 1973-10-02 for nebulizer.
Invention is credited to Victor E. Lester.
United States Patent |
3,762,409 |
Lester |
October 2, 1973 |
NEBULIZER
Abstract
A disposable nebulizer device for producing aerosol includes an
enclosed container having an aerosol outlet, a nozzle assembly
extending into the container, and a diffuser-baffle assembly in the
container. The nozzle assembly includes a gas nozzle and a spray
nozzle with spaced and coaxially positioned orifices. The
diffuser-baffle assembly is located in the spray path of the spray
orifice and includes a nose portion which extends towards the
orifices and is coaxially positioned therewith.
Inventors: |
Lester; Victor E. (Sanora,
CA) |
Family
ID: |
22199145 |
Appl.
No.: |
05/086,525 |
Filed: |
November 3, 1970 |
Current U.S.
Class: |
128/200.14;
239/424; 261/78.2 |
Current CPC
Class: |
B05B
7/0012 (20130101); A61M 11/002 (20140204); A61M
11/06 (20130101); B05B 7/2435 (20130101) |
Current International
Class: |
A61M
11/06 (20060101); B05B 7/00 (20060101); A61M
11/00 (20060101); A61m 011/00 () |
Field of
Search: |
;128/194,188,193,145.8,145.6,145.5 ;239/424,523
;261/78,115,118 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Dunne; G. F.
Claims
I claim:
1. A nebulizer for converting liquid into aerosol, comprising;
a housing having a liquid reservoir and an outlet opening through
which aerosol passes;
a spray nozzle having an end wall defining an orifice and having
liquid inlet means in communication with said reservoir;
a gas nozzle positioned within said spray nozzle having gas inlet
means and an orifice spaced from and co-axial with said spray
orifice;
said spray nozzle and said gas nozzle defining a passage
therebetween extending from said liquid inlet means to said space
between said orifices;
a diffuser having a nose portion spaced from and adjacent said
orifices with the furthermost extension of said nose portion
coaxial with said orifices, said nose portion having a surface or
revolution diverging from said furthermost extension away from said
orifices; and
said end wall having an outer surface extending outwardly from said
spray orifice in a direction substantially parallel to the
diverging surface of said nose portion with said outer surface of
said end wall and said diverging surface of said nose portion
defining a narrow path through which spray passes from said spray
orifice.
2. The nebulizer of claim 1, wherein the distance between the outer
surface and the inner surface of said spray nozzle at the edge of
said spray orifice is about 0.015 inch to minimize noise.
3. The nebulizer of claim 1, wherein said spray orifice is defined
by an end wall of said spray nozzle, said end wall having a recess
coaxial with said spray orifice on the outer surface of said end
wall to reduce the thickness of said end wall at the edge of said
spray orifice to prevent noise while permitting injection-molding
of said end wall.
4. The nebulizer of claim 1, wherein the distance between said
furthermost extension of said nose portion and said spray orifice
is about 0.030 inch.
5. The nebulizer of claim 1, wherein the distance between the inner
surface of said end wall of said spray nozzle and the outer surface
of said end wall of said gas nozzle at said space between said
orifices is between about 0.012 inch and 0.015 inch.
6. The nebulizer of claim 1, wherein the distance between the inner
surace of said end wall of said spray nozzle and the outer surface
of said end wall of said gas nozzle in said passage is less than
the diameter of said spray orifice.
7. The nebulizer of claim 1, wherein a baffle plate is provided,
said baffle plate being positioned in the path of spray emanating
from said spray orifice and adjacent said aerosol outlet to prevent
oversize droplets of liquid from escaping the nebulizer.
8. The nebulizer of claim 1, wherein said gas inlet means is
provided with a check valve to prevent a back flow of liquid
through said gas nozzle.
9. The nebulizer of claim 1, wherein the inner surface of said end
wall extending from said spray orifice is parallel to the outer
surface of said end wall extending radially from said gas
orifice.
10. A nebulizer for converting liquid into aerosol,
compressing;
an enclosed container having a liquid supply reservoir and an
aerosol outlet;
a nozzle assembly extending into said container including an inner
gas nozzle and an outer spray nozzle encircling said gas
nozzle;
said gas nozzle having an end wall defining a gas orifice and said
spray nozzle having an end wall defining a spray orifice spaced
from and coaxial with said gas orifice;
said end walls having a passage therebetween extending to said
space between said orifices;
said gas nozzle having a gas inlet means in communication with said
gas orifice and said spray nozzle having liquid inlet means in
communication with said reservoir and said passage;
a diffuser in said container having a nose portion adjacent said
orifices with the furthermost extension of said nose portion sapced
from and coaxial with said spray orifice, said nose portion having
a surface of revolution diverging from said furthermost extension
away from said spray orifice; and
said end wall of said spray nozzle having an outer surface
extending outwardly from said spray orifice in a direction
substantially parallel to said diverging surface of said nose
portion with said outer surface of said end wall and said diverging
surface of said nose portion defining a narrow path through which
spray passes from said spray orifice.
11. The nebulizer of claim 10, wherein the outer surface of said
end wall of said spray nozzle is provided with a recess coaxial
with and surrounding said spray orifice.
12. The nebulizer of claim 11, wherein said nose portion of said
diffuser extends into said recess.
13. The nebulizer of claim 10, wherein the distance between said
furthermost extension of said nose portion and said spray orifice
is about 0.030 inch.
14. The nebulizer of claim 10, wherein the distance between the
inner surface of said end wall of said spray nozzle and the outer
surface of said end wall of said gas nozzle at said space between
said orifices is between about 0.012 inch and 0.015 inch.
15. The nebulizer of claim 10, wherein the diameter of said gas
orifice is between about 0.024 inch and 0.028 inch and the diameter
of said spray orifice is between about 0.036 inch and 0.042
inch.
16. The nebulizer of claim 10, wherein the distance between the
inner surface of said end wall of said spray nozzle and the outer
surface of said end wall of said gas nozzle in said passage is less
than the diameter of said spray orifice.
17. The nebulizer of claim 10, wherein a baffle plate is provided,
said baffle plate being positioned in the path of spray emanating
from said spray orifice and adjacent said aerosol outlet to prevent
oversize droplets of liquid from escaping the nebulizer.
18. The nebulizer of claim 10, wherein said gas inlet means is
provided with valve means to prevent a back flow of liquid passing
through said gas nozzle.
19. The nebulizer of claim 10, wherein the inner surface of said
spray nozzle is provided with at least three ribs engaging the
outer surface of said gas nozzle to position and maintain said gas
orifice with respect to said spray orifice.
20. A disposable, preferably plastic nebulizer unit for converting
liquid medicament into aerosol, comprising:
four separately molded components comprising an outlet component, a
cover component, a bowl component, and a gas nozzle component;
said outlet component having an aersol outlet end, an aerosol inlet
end, and an aerosol passageway therebetween;
said cover component and said bowl component each having sidewalls
connected together at one end, said sidewalls together defining a
container having an upper mixing area and a lower reservoir
area;
said gas nozzle component and said bowl component being connected
together with a section of said gas nozzle component extending into
said container, said gas nozzle component having a gas orifice
inside said container and a gas inlet end outside said container in
communication with said gas orifice;
said bowl component having an integral spray nozzle within said
container, said spray nozzle having an end wall defining an orifice
and liquid inlet means in communication with said reservoir area
and said spray orifice, said spray orifice being positioned above
said reservoir area and spaced from and coaxial with said gas
orifice;
said cover component being connected to said aerosol inlet end and
having an outlet opening for communication of aerosol between said
mixing area and said aerosol inlet end, said cover component
further including an integral diffuser-baffle assembly positioned
within said container between said outlet opening and said coaxial
orifices; and
said diffuser-baffle having a nose portion spaced from and adjacent
said orifices with the furthermost extension of said nose portion
coaxial with said orifices, said nose portion having a surface or
revolution diverging from said futhermost extension away from said
orifices; and
said end wall having an outer surface extending outwardly from said
spray orifice in a direction substantially parallel to the
diverging surface of said nose portion with said outer surface of
said end wall and said diverging surface of said nose portion
defining a narrow path through which spray passes from said spray
orifice.
Description
This invention relates to a new and improved liquid nebulizing
device and more particularly relates to a disposable, preferably
plastic, nebulizer having improved aerosol production.
Nebulizers are pneumatic devices for breaking up a liquid
medicament into small particles and to entrain the small liquid
particles in the stream of air or gas thereby providing an aerosol
for inhalation therapy in the treatment of respiratory system
disorders. It is important during such thereapy that there be a
sufficient quantity and proper formation of aerosol provided by the
nebulizer. If the particles or droplets of the medicament are too
fine, they are not likely to be retained in the respiratory tract,
but will, to a great extent, be exhaled. If the particles are too
large, they will likely be deposited on the upper reaches of the
respiratory system, such as the trachea and the upper
tracheal-bronchial tree, thereby leaving the rest of the system
untreated. It is also important that the aerosol be delivered to
the patient in a smooth, uniform manner.
Production of a proper aerosol is substantially dependent on the
design of the nebulizer. Prior to my U.S. Pat. No. 3,097,645, it
was conventional to employ the fly-spray principle of aerosol in
the design of nebulizers. This principle involves directing a
stream of gas from a nozzle at right angles across the open end of
a tube running to the liquid medicament. Proper positioning and
sizing of the tube and nozzle are extremely critical and the design
of a nebulizer employing this principle is such that it is
difficult and expensive to manufacture, particularly if the
nebulizer is to be made of plastic.
Often fly-spray nebulizers are made of glass and therefore are very
delicate and must be handled with a great degree of care. However,
because of the relatively high cost of such nebulizers it is not
practical to dispose of them after use and therefore these
nebulizers must undergo periodic cleaning. This cleaning process is
expensive and in addition frequently results in breakage.
On the other hand, a nebulizer of the type shown in my previously
referred to U.S. Pat. No. 3,097,645 is simple and inexpensive to
manufacture. Also, the design of this type nebulizer is such that
the device can be easily formed of plastic and the device is
relatively unbreakable. Moreover, because this type nebulizer can
be produced at a marked reduction in cost, the entire nebulizer can
be disposed of after use thereby avoiding the costs of cleaning.
The present invention represents an improved form of this
particular type of nebulizer and employs certain elements of this
nebulizer. However, the present invention also includes numerous
details of construction not shown in any previous nebulizer devices
which produce new and improved results.
It is therefore a primary object of this invention to provide a
nebulizer having improved aerosol production and improved operating
characteristics. In accordance with this and other objects, the
nebulizer of the present invention includes a container having a
aerosol outlet, a nozzle assembly extending into the container
having a gas orifice and a spray orifice spaced from and coaxial
with the gas orifice, and a diffuser-baffle assembly positioned
within the container in the spray path of the spray orifice. When
gas is passed through the gas orifice liquid is drawn from the
container into the space between the orifices and then carried in
the form of small particles through the spray orifice. The spray
nozzle is provided with a recessed portion on its outer surface
surrounding the spray orifice to minimize noise created by the
spray. A nose portion of the diffuser-baffle assembly extending
towards the spray orifice and concentric therewith provides for
improved performance and a baffle plate prevents oversize liquid
particles from passing out through the aerosol outlet.
Another object of this invention is to provide a plastic disposable
nebulizer which is simple and inexpensive to manufacture.
Other objects and advantages of this invention will be apparent
from the following description and accompanying drawings.
In the drawings:
FIG. 1 is a side sectional view of the nebulizer.
FIG. 2 is a cross-sectional view taken substantially on the lines
2--2 of FIG. 1 illustrating the nozzle assembly.
FIG. 3 is a cross-sectional view taken substantially on the lines
3--3 of FIG. 1 illustrating the liquid inlet means of the spray
nozzle.
FIG. 4 is a cross-sectional view taken substantially on the lines
4--4 of FIG. 1.
FIG. 5 is a cross-sectional view illustrating the respective
positioning of the gas orifice, spray orifice and nose portion of
the diffuser-baffle assembly.
Referring now in detail to the drawings, the nebulizer device,
generally designated 10, is preferably constructed of a plastic
material such as crystal polystyrene and includes essentially four
separately molded components, an aerosol outlet component 11, a
cover component 12 including the diffuser-baffle assembly, a bowl
component 13 including the spray nozzle, and a gas nozzle component
14. Because of their shape, each components may quickly and easily
be injection-molded and then assembled without the need for
extensive additional machining.
The aerosol outlet component 11 comprises a slightly tapered,
tubular member 15 having proximate its lower end a circumfenential
flange 16 which forms a shoulder 17. The cover component 12
includes a cylindrical sidewall 18 which terminates at its upper
end in an annular flange 19 forming a central opening 20. The lower
end of the aerosol outlet component 11 fits into the opening 20
with the shoulder 17 abutting the flange 19. The upper end of the
aerosol outlet component 11 may be adapted to fit into a
conventional inhalation mask or other device for attaching the unit
to the patient or it may be used as a mouthpiece which is inserted
into the mouth of the patient.
The bowl component 13 is generally cup shaped with the lower
portion of the bowl narrowing down and the upper portion forming a
generally cylindrical sidewall which is adapted to join at its
upper end 21 the lower end 22 of the cylindrical sidewall 18. An
interlocking V-tongue 23 and V-groove 24 are provided on the lower
end 22 and the upper end 21, respectively, to insure proper
alignment of the bowl and cover components. Together, the bowl
component 13 and the cover component 12 form a container, generally
designated 25, having a smooth inner surface 26 which defines a
mixing area 27 in the upper portion of the container 25 and a
reservoir area 28 in the lower portion of the container 25. The
reservoir 28 is adapted to hold about 8 cubic centimeters of liquid
medicament and the mixing area is of sufficient volume to minimize
the attractive action of the plastic material for the droplets of
medicament which otherwise might interfere with the operation of
the nebulizer.
The bowl component 13 is also provided with a central opening 29 at
its lower end. The edge 30 of the opening 29 includes three
inwardly extending, integrally formed ribs 31 and the outer surface
of the bowl surrounding the opening 29 defines a flat cylindrical
collar 32. The gas nozzle component 14 extends into the opening 29
and includes a shoulder 33 proportioned to seat upon the collar 32.
The shoulder 33 is relatively wide to provide a sturdy, firm
support for the nozzle component 14 at the collar 32 and the three
ribs 31 assist in properly positioning the gas nozzle component
14.
During assembly the aerosol outlet component 11, the cover
component 12, the bowl component 13, and the gas nozzle component
14 are joined together by a suitable means, preferably by an
ultra-sonic sealing process, to form a durable unit. The nozzle
assembly, generally designated 34 includes a spray nozzle 35 which
is an integrally molded element of the gas nozzle component 14. The
spray nozzle 35 extends upwardly from the lower end of the inside
surface of the bowl component 13 and is slightly tapered and
tubular in form. The upper end of the spray nozzle 35 curves
inwardly to form an end wall or annular flange 37 with a centrally
positioned round spray orifice 38. The outer surface 39 of the end
wall 37 is provided with a frusto-conical recess 40 which is
coaxial with and surrounds the spray orifice 38. At the lower end
of the spray nozzle 35 is a series of liquid inlets 41, equally
spaced around the base of the spray nozzle 35, and communicating
with the reservoir 28 so that liquid medicament may flow
unrestricted into the inside of the spray nozzle 35.
In determining the diameter of the spray orifice 38, consideration
must be given to the rate of gas flow through the nebulizer and the
viscosity of the liquid medicament to be nebulized. When used with
a gas flow of between about 3 to 8 liters per minute and a thin
liquid with a viscosity approximately that of water, a spray
orifice 38 having a diameter within the range of about 0.036 and
0.042 inch produces a satisfactory aerosol. If the gas flow rate is
extended outside this range, and/or a more viscous liquid is used,
then compensation should be made in the diameter of the spray
orifice 38 to obtain the desired aerosolization.
Also of importance is the distance between the inner surface 42 of
the end wall 37 and the outer surface 39 of the end wall 37 at the
edge 43 of the orifice 38. In accordance with the gas flow and the
liquid viscosity set forth above it has been found that a distance
of about 0.015 inch is preferable to prevent noise when spray
eminates from the spray orifice 38. This distance at the edge 43 of
the spray orifice 38 is achieved by the recess 40 while still
permitting injection molding of the end wall 37.
The size of the liquid inlets 41 are not as critical. Substantially
any opening which will permit sufficient flow of liquid from the
reservoir 28 into the inside of the spray nozzle 35, to manitain a
constant full supply of liquid at the top of the air nozzle 36,
will suffice.
As stated previously the gas nozzle 36 is an integrally molded
element of the gas nozzle component 14 and it extends upwardly from
the shoulder 33. The gas nozzle component 14 serves as an inlet for
the carrier gas which is normally compressed air or oxygen and
therefore is also provided with a connector element 44 which
extends downwardly from the shoulder 33 and is adapted to be
secured to a flexible hose or other suitable means for
communicating the gas to the gas nozzle component 14. The gas
nozzle 36 is also slightly tapered from bottom to top, to conform
generally with the taper of the spray nozzle 35, and terminates at
its upper end in an end wall or annular flange 45 having a
centrally positioned orifice 36. The gas nozzle component 14 is
also provided with a gas inlet passage 47 which extends from the
lower end of the connector element 44 to the gas orifice 46. A
check valve 48 positioned within the gas inlet passage 47, permits
the upward flow of gas through the inlet passage 47, but prevents a
back flow of liquid from the container from passing out through the
gas inlet passage 47.
When the gas nozzle 36 is inserted into place inside the spray
nozzle 35, the gas orifice 46 and the spray orifice 38 are coaxial
and spaced apart a predetermined distance. The space between the
gas orifice and the spray orifice is properly determined and
maintained by the seating of the shoulder 33 with the collar 32.
The coaxial relationship of the orifices is properly determined and
maintained by the ribs 31 engaging an annular flange 49 at the
lower end of the gas nozzle 36 and by three other integrally formed
and equally spaced ribs 50 of the spray nozzle 35. The ribs 50
extend radially inward from the inner surface 51 of the sidewall 52
of the spray nozzle 35 and engage the outer surface 53 of the
sidewall 54 of the gas nozzle 36 proximate the upper end of the gas
nozzle 36.
The inner surface 51 and the outer surface 53 of the sidewalls 52
and 54, respectively, of the nozzles and the inner surface 42 and
the outer surface 55 of the end walls 37 and 45, respectively, of
the nozzles also define a passage 56 which extends from the liquid
inlets 41 through the space between the ribs 50 to the space
between the orifices 38 and 46.
As with the spray orifice 38, there is a relationship between the
diameter of the gas orifice 46, the gas flow rate, and the
viscosity of the liquid. Based upon a gas flow of from 3 to 8
liters per minute, and a thin liquid with a water like viscosity,
the diameter of the gas orifice 46 should be between about 0.024
and 0.028 inch. Where gas flow rates outside of this range are
used, and/or more viscous liquids are to be nebulized, the diameter
of the gas orifice 46 should be altered to that providing the
desired result.
Along with the foregoing relationships, for satisfactory results
the distance between the inside surface 42 of the end wall 39 of
the spray nozzle 35 and the outside surface 55 of the end wall 45
of the gas nozzle 36 at the space betwen the orifices should be
between about 0.012 and 0.015 inch, where the diameter of the spray
orifice 38 is between about 0.036 and 0.042 inch, and the diameter
of the gas orifice 46 is between about 0.024 and 0.028 inch. If
this distance is greater than about 0.015 inch large droplets are
produced instead of a fine aerosol.
The diffuser-baffle assembly, generally designated 57, is an
integrally formed element of the cover component 12. The
diffuser-baffle assembly 57 includes a circular baffle plate 58
having approximately the same diameter as the lower open end 59 of
the aerosol outlet component 11. The baffle plate 58 is supported
by three equally spaced legs 60 depending from the inside surface
of the annular flange 19 of the cover component 12 adjacent the
edge of the opening 20. The baffle plate 58 assists in separating
from the aerosol spray emanating from the spray orifice 38 the
coarser drops, so that only a fine aerosol flows around the edge of
the baffle plate 58 through the aerosol outlet to the patient. The
large separated droplets that strike the baffle plate 58 drop back
into the liquid in the reservoir 28. The underside surface 61 of
the baffle plate includes a generally centrally positioned diffuser
member 62 extending downwardly therefrom. The downwardly extending
lower end of the diffuser member 62 comprises a nose portion 64
spaced from the spray orifice 38 with the furthermost downward
extension 65 of the nose portion 64 extending about 0.030 inch from
the spray orifice 38 and being coaxial therewith. The nose portion
64 includes a generally rounded surface of revolution 66 diverging
from the furthermost extension 65 away from the spray orifice 38
thereby defining a path 67 for the aerosol spray emanating from the
spray orifice 38 between the surface of the recess 40 and the
surface of the nose portion 64.
In operation, the reservoir 28 of the nebulizer 10 is filled to a
level below the top of the spray nozzle 35 with a liquid medicament
or theraputic. A suitable source of compressed gas is communicated
to the gas nozzle 36 by a suitable conduit (not shown) attached to
the connector member 44 and the outer end of the aerosol outlet 11
is attached to a mask covering the patient's face.
As gas courses upwardly through the gas nozzle 36 and exits through
the gas orifice 46, it creates a partial vacuum in the space
between the orifices 46 and 38. This vacuum causes the level of the
liquid medicament in the passage 56 between the nozzles 35 and 36
to rise and flow over the top of the nozzle 36. When the stream of
gas strikes this liquid it entrains it in droplet form and carries
it along upwardly through the spray orifice 38 and then through the
path 67 which promotes aerosolization. The spray then continues
upward where a substantial portion strikes the underside surface 61
of the baffle plate 58 to remove oversize droplets of liquid. After
the oversize droplets are removed, the aerosol spray eventually
migrates around the edge of the baffle plate 58 through the aerosol
outlet component 11 and then on into the patient's respiratory
tract. Since the bottom portion of the reservoir area 28 tapers
down to a narrow confine at the inlets 41, substantially all of the
liquid medicament is used before replenishing is necessary.
This invention provides an inexpensive to manufacture, durable
nebulizer which because of its low cost of production may be
disposed of after use. The nozzle assembly and the diffuser-baffle
assembly of the nebulizer minimize noise during operation, provide
for proper control of the liquid medicament particles in the
aerosol and promote improved aerosolization.
Having fully described my invention, it is to be understood that I
do not wish to be limited to the details herein set forth, but my
invention is of the full scope of the appended claims.
* * * * *