U.S. patent number 3,836,079 [Application Number 05/277,469] was granted by the patent office on 1974-09-17 for fluid dispensing device.
This patent grant is currently assigned to Becton, Dickinson and Company. Invention is credited to Paul O. Huston.
United States Patent |
3,836,079 |
Huston |
September 17, 1974 |
FLUID DISPENSING DEVICE
Abstract
A fluid dispensing device for providing a controlled ratio of a
mixture of fluids introduced to the device. The device includes a
container having an inlet section and an outlet section. The
container is designed for contents used in treating a fluid mixture
introduced through the inlet section. The inlet section is adapted
to be connected to a source of a first fluid and has at least one
opening therein of a predetermined size and configuration. A sleeve
is movably mounted on the inlet section and has at least one
opening therein of a predetermined size and configuration and is
positioned so that movement of the sleeve with respect to the inlet
section will determine the relative alignment of the openings. In
this manner, the portion of the openings in the inlet section
exposed to a source of the second fluid will be varied and the
ratio of second fluid with respect to first fluid in the mixture
introduced to the container is controlled. The outlet section
provides for discharging the treated fluid mixture.
Inventors: |
Huston; Paul O. (Montville,
NJ) |
Assignee: |
Becton, Dickinson and Company
(East Rutherford, NJ)
|
Family
ID: |
23061014 |
Appl.
No.: |
05/277,469 |
Filed: |
August 2, 1972 |
Current U.S.
Class: |
239/74;
128/200.18; 239/347; 239/338; 261/DIG.65 |
Current CPC
Class: |
A61M
16/125 (20140204); A61M 16/12 (20130101); A61M
16/16 (20130101); Y10S 261/65 (20130101); A61M
11/06 (20130101) |
Current International
Class: |
A61M
16/16 (20060101); A61M 16/10 (20060101); A61M
16/12 (20060101); A61M 11/06 (20060101); B05b
007/24 () |
Field of
Search: |
;239/74,338,347,354
;222/28,29,48 ;128/194 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Love; John J.
Attorney, Agent or Firm: Kane, Dalsimer, Kane, Sullivan and
Kurucz
Claims
I claim:
1. A fluid dispensing device for providing a controlled ratio of a
mixture of fluids introduced to the device comprising:
a container having an inlet section and an outlet section;
means within said container for treating a fluid mixture introduced
through the inlet section;
inlet means on said inlet section adapted to be connected to a
source of a first fluid;
said inlet section having at least one opening therein of a
predetermined size and configuration;
a sleeve movably mounted on said inlet section and having at least
one opening therein of a predetermined size and configuration and
positioned so that movement of said sleeve with respect to said
inlet section will determine the relative alignment of said
openings whereby exposure of the at least one opening in the inlet
section to a source of a second fluid will be varied and the ratio
of second fluid with respect to first fluid in the mixture
introduced to the container is controlled;
outlet means at said outlet section for discharging the treated
fluid mixture;
indicator means positioned on the container and responsive to the
position of the openings in said sleeve and said inlet section to
indicate the relative percentages of the first and second fluids in
the mixture;
the inlet section includes a cylindrical throat section and the
openings in the inlet section being lateral openings in the
cylindrically shaped throat section;
the sleeve being substantially cylindrical in shape and in
surrounding engagement with the cylindrical throat section and
having its openings laterally positioned thereon;
said cylindrical sleeve being rotatable about said cylindrical
throat section to bring the lateral openings in the throat section
and the sleeve into and out of alignment with one another;
at least two lateral openings in the cylindrical throat section and
being spaced about the circumference of the throat section and at
least one being irregular in configuration to facilitate
introduction of a multiplicity of different accurate percentages of
fluid mixtures;
the irregularly shaped lateral opening being of substantially
gradually increasing diameter as it extends around the
circumferential surface of the throat section thereby providing for
gradual and closely controlled adjustment of the ratio between the
fluids in the mixture; and
the indicia on the annular flange arranged to coincide with the
various alignments between the openings in the cylindrical throat
section and the sleeve so as to provide readings of percent of the
first fluid in the mixture of 30 percent and at least four other
accurate and discrete percentages of first fluid.
2. The invention in accordance with claim 1 wherein the cylindrical
throat section has a downwardly depending hollow collar extending
therefrom and in fluid communication and in cooperation therewith
for facilitating mixture of the fluids received through said inlet
section.
3. The invention in accordance with claim 1 wherein the lateral
openings in the cylindrical sleeve are of substantially the same
size and are rectangular in configuration, one of the openings in
the cylindrical throat section is rectangular in configuration and
substantially the same size as the openings in the sleeve, the
other of said openings in the throat section having a rectangular
portion substantially the same size as the openings in the sleeve
and having communication with a pair of adjacent smaller portions
of the opening, the first adjacent smaller portion being
substantially rectangular in configuration and approximately
one-quarter the size of the openings in the sleeve and tapering
from a smaller to a larger size as it approaches the other opening
in the throat section, the second adjacent opening portion being
smaller than the first adjacent opening portion and tapering from a
smaller to a larger size as it approaches the first adjacent
opening portion.
4. The invention in accordance with claim 1 wherein the first fluid
is oxygen and the second fluid is air and the indicia on the
annular flange gives readings of percent oxygen in the mixture of
30, 40, 60, 70 and 100 percent.
5. The invention in accordance with claim 1 wherein the inlet means
is adaptable for connection to a source of an inhalable gas to be
introduced under pressure into said container, an aspirator
positioned in said inlet section including a first nozzle in fluid
flow communication with said inlet means for directing the gas
downwardly, a second nozzle positioned crosswise and adjacent said
first nozzle for the education of a spray of fluid therefrom, a
siphon tube in fluid flow communication with said second nozzle and
extending downwardly into the container containing fluid, and a
baffle member adjacently below said nozzle onto which the spray of
the fluid is directed to nebulize the same.
Description
BACKGROUND OF THE INVENTION
In controlling fluid flow, particularly in the medical field, it is
often necessary to closely control the mixture of fluids in a
system. This is extremely important when dealing with inhalable
fluid mixtures such as in breathing apparatus. In connection with
inhalable fluid devices, the basic fluid mixture is often comprised
of oxygen and atmospheric air. Depending upon the condition of the
patient and the circumstances under which the mixture is being
employed the ratio of outside air to pure oxygen is often of
concern. Additionally, devices such as nebulizers are frequently
utilized to handle the mixture of oxygen and air and to treat the
mixture before passing it on to a patient. In the case of a
nebulizer, this is done by treating the mixture of oxygen and air
with a fine spray of moisture.
There are a number of prior art devices which teach the treating of
the oxygen and air mixtures in order to properly feed the desired
fluid to the breathing system of the patient. However, it is often
desirable to control the percentage of outside air entrained with
the oxygen being fed into the system. Known devices are adapted to
generally control whether or not air is mixed with the oxygen and
to broadly determine the approximate ratio of outside air to
oxygen. No known device is capable of adjusting the percentage of
outside air to oxygen at a multiplicity of different percentage
ratios along the majority of the scale from 30 to 100 percent.
This shortcoming is particularly prevalent in the system utilized
in handling inhalable fluid mixtures. For example, known nebulizer
devices have means to provide openings so that a 100 percent oxygen
condition can be reduced by providing openings to the outside air
in the feeding system. The greatest disadvantage of the known
systems is in controlling the percentage of outside air to oxygen
by being able to increase and reduce the amount of outside air at
will and also to be able to readily indicate and determine specific
percentages of oxygen to outside air being fed to the fluid system
at any given point in time and in regard to any given position of
adjustable elements.
An additional shortcoming of the prior art when devices such as
nebulizers are considered is that common nebulizers in use today
for oxygen administration lack the ability to entrain a sufficient
quantity of air to vary the oxygen percentage being administered.
It is highly desirable to have the capability to mix air with the
oxygen and to be able to control the ration from 100 percent oxygen
to as low a percentage of oxygen as physical conditions make
possible. Naturally, the oxygen content can never be zero since
atmospheric air contains approximately 21 percent of oxygen
content.
SUMMARY OF THE INVENTION
With the above considerations in mind, it is among the primary
objectives of the present invention to provide a fluid dispensing
device which is designed to closely control a wide range of fluid
mixture ratios introduced into a fluid system. Control means are
provided on the device to closely control the percentage of one
fluid with respect to the other fluid and to indicate the ratios at
a plurality of different points between 30 and 100 percent of one
fluid with respect to the other. A low cost, economical to
manufacture device is provided with control means and indicator
means thereon to adjust and control the percentage of one fluid of
a fluid mixture with respect to the other at any time during the
operation of the system quickly and efficiently with a simple
manual adjustment on the device.
The device is particularly useful in an environment employing
inhalable fluids such as in regard to a nebulizer which treats a
mixture of air and oxygen gases introduced in a breathing system
with moisture. The device is designed to mix air with oxygen from a
condition of 100 percent pure oxygen to as low a percentage of
oxygen as possible which would approach that which is contained in
atmospheric air. In addition, the controls and indication means on
the device are such that the percentage of oxygen to air can be
determined at any desired ratio from the device and can be varied
at will.
In summary, a fluid dispensing device is provided to contain means
for providing a controlled ratio of a mixture of fluids introduced
into the device. The device includes a container having an inlet
section and an outlet section. Means are within the container for
treating a fluid mixture introduced to the inlet section. The inlet
means are on the inlet section adapted to be connected to a source
of a first fluid. The inlet section has at least one opening
therein of a predetermined size and configuration. A sleeve is
movably mounted on the inlet section and has at least one opening
therein of a predetermined size and configuration. The opening is
positioned so that movement of the sleeve with respect to the inlet
section will determine the relative alignment of the openings. In
this manner, the portion of the openings in the inlet section
exposed to a source of a second fluid will be varied and the ratio
of second fluid with respect to the first fluid in the mixture
introduced to the container is controlled. Finally, outlet means
are at the outlet section for discharging the treated fluid
mixture.
For descriptive purposes in the present disclosure, the invention
will be described in the inhalable fluid environment, particularly
in use as a nebulizer. The nebulizer is usually operated from a 50
psig Nom. oxygen supply. Air may be used if desired. The nebulizer
produces a finely divided aerosol predominantly containing moisture
particles between 1.0 and 1.8 microns in diameter. In operation of
the device shown, gas flowing through the vertical gas jet past the
horizontal liquid feed jet, creates a low pressure area in front of
the liquid feed jet as a result of the Bernouli effect. The liquid
jet is positioned so that the high velocity gas shears through the
immerging liquid stream. The liquid jet is positioned so that the
high velocity gas shears through the immerging liquid stream,
breaking it into small aerosol particles. A central baffle
comprised of a solid cylinder with a hemispherical end, and
vertical tubular baffle called a throat, are so sized and
positioned that they produced the quality of aerosol particle size
described above.
The nebulizer permits preselection of the oxygen concentration of
the effluent gas when operating from an oxygen supply. The selected
concentration is maintained between nominally plus or minus 5
percent of set concentration while the oxygen supply flow may be
allowed to vary through the predominantly used flow range of 4 to
12 liters per minute. To accomplish this, a particular aspiration
geometry is provided in the depicted device.
With the above objectives, among others, in mind, reference is had
to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings;
FIG. 1 is a partially sectional side elevation view of a fluid
dispensing device of the invention;
FIG. 2 is a top plan view thereof;
FIG. 3 is an enlarged fragmentary sectional view of the inlet
section thereof taken along the plane of line 3--3 of FIG. 2 with
arrows showing the path of flow of fluid entering the device;
FIG. 4 is an enlarged fragmentary elevation view of the inlet
section of the device with its sleeve section in cross section and
showing one of the openings in the throat section thereof;
FIG. 5 is a fragmentary perspective view of the inlet section
portion of the device of the invention showing the elements in
position for a ratio of outside air to oxygen which provides a
fluid mixture of 30 percent oxygen;
FIG. 6 is a fragmentary top sectional view of the sleeve and throat
section portions taken along the plane of line 6--6 of FIG. 5;
FIG. 7 is a fragmentary perspective view of the inlet section of
the device showing the elements positioned for a ratio of outside
air to oxygen which provides a fluid mixture of 40 percent
oxygen;
FIG. 8 is a fragmentary top sectional view of the sleeve and throat
sections thereof taken along the plane of line 8--8 of FIG. 7;
FIG. 9 is a fragmentary perspective view of the inlet section of
the device showing a ratio of outside air to oxygen which provides
a fluid mixture of 60 percent oxygen;
FIG. 10 is a fragmentary top sectional view of the sleeve and
throat section taken along the plane of line 10--10 of FIG. 9;
FIG. 11 is a fragmentary perspective view of the inlet section of
the device shown in position to provide a ratio of outside air to
oxygen in the fluid mixture which provides a 70 percent oxygen
mixture;
FIG. 12 is a fragmentary sectional top view of the sleeve and
throat section taken along the plane of line 12--12 of FIG. 11;
FIG. 13 is a fragmentary perspective view of the inlet section of
the invention showing the elements in position to provide a fluid
mixture of outside air to oxygen which provides a fluid mixture of
100 percent oxygen; and
FIG. 14 is a fragmentary top sectional view of the sleeve and
throat section taken along the plane of line 14--14 of FIG. 13.
DESCRIPTION OF THE PREFERRED EMBODIMENT
For descriptive purposes, a fluid dispensing device of the present
invention is depicted in the form of a nebulizer 20 adapted for use
in an inhalable fluid system. As shown in FIG. 1, the device or
nebulizer 20 includes a jar base 21 and a top portion 22. The
entire nebulizer 20 can be constructed of any convenient, low cost
material such as plastic which lends itself to disposability. The
undersurface of the cap 22 contains threads which are
interengageable with a threaded top portion on the jar 21 to form
the coupled container or nebulizer 20. The jar portion forms a
receptacle for a fluid, preferably a liquid such as water which is
adapted to be utilized in treating a gaseous mixture in a manner
described below to provide a treated fluid for a patient to
breath.
The top 22 contains an outlet section including a nozzle 24 which
is open to the interior of the container 20 to receive the threated
fluid mixture and is hollow with an opening 25 at its outer end for
connection to a hose which in turn is directed in a convenient
manner to a patient. At the apex of top 22 is a removable adapter
26 which has an upper ribbed end portion 27 which interengages with
a hose 28 from an oxygen source in an interlocking manner as shown
in FIG. 3. The lower end portion of adapter 26 has a threaded outer
surface 29 which engages with the threaded inner surface 30 of
hollow cap 31. Hollow cap 31 has a ribbed outer surface 32 to
facilitate its rotation and has an annular flange 33 extending from
its undersurface for interengagement with a corresponding annular
flange 34 on the top of neck 35 of the cap 22. Spaced below flange
24 at a distance greater than the thickness of flange 33 is an
annular ring 36 so that flange 34 and ring 36 retain cap 31 on neck
35. By providing the additional spacing between flange 34 and ring
36 cap 31 is given limited vertical freedom of movement.
Additionally, the inner diameter of flange 33 is greater than the
outer diameter of neck 35 at the point where it is proximal to neck
35 thereby permitting cap 31 to rotate freely about neck 35 and
permitting cap 31 to be threadedly interengaged with adapter 26. In
this manner, container 20 can be connected to a source of oxygen
which is received through hose 28.
An inlet nozzle 37 is mounted in neck 35 in a convenient manner
such as by interengagement between the ribs 38 on the exterior
surface of nozzle 37 and the ribs 38 on the exterior surface of
nozzle 37 and the interior surface of neck 35. Additionally,
engagement between the undersurface of adapter 26 and an annular
ring on nozzle 38 can be utilized to assist in holding the nozzle
in fixed position. The nozzle has a through passageway 39 which
receives oxygen from tube 28 as shown by arrows in FIG. 3 until it
is forced out of narrow aperture 40 at the lower end of the nozzle.
By the Bernouli effect the rapidly moving oxygen passing from small
aperture 40 at the lower end of nozzle 37 causes a lowering of the
pressure at lateral aperture 41 of downwardly extending extension
42 of nozzle 37. The lower end of extension 42 is open providing a
passageway to narrow lateral aperture 41 and is of a large enough
diameter to receive siphon tube 43. The siphon tube 43 is in
frictional interengagement with the inner walls of the lower
portion of extension 42. As shown by the arrows in FIG. 3, the
pressure reduction created by the high speed flow of oxygen from
aperture 40 past aperture 41 draws fluid 23 from container 21 up
through siphon tube 43 and out through aperture 41.
A predetermined amount of outside air is also introduced into the
working chamber 43' where apertures 40 and 41 are located. A hollow
cylindrical portion of top 22 which is generally referred to as a
throat section 44 contains chamber 43' and the structure adjacent
to apertures 40 and 41. Throat section 44 is integral with neck 35
and with the remainder of top 22 of device 20. A collar 45 is
frictionally mounted inside of the lower end of throat section 44
and extends downwardly into container 21. The upper end of collar
45 opens into chamber 43' and the lower end of collar 45 is open to
the interior of container 21. Siphon tube 43 extends upwardly
through collar 45 into engagement with extension 42.
Laterally extending from extension 42 and in alignment with the
flow path of oxygen from aperture 40 is baffle 46. Oxygen from
aperture 40 in combination with a predetermined amount of outside
air along with liquid drawn from aperture 41 by the Bernouli effect
are directed against baffle 46. This action breaks up the liquid
into a fine spray mist which is carried in the form of a fluid
mixture with the oxygen and outside air down through collar 45 and
out through outlet nozzle 24 to a breathing hose connected to
opening 25 of outlet nozzle 24.
To facilitate introduction of outside air for combination with the
oxygen entering chamber 43' through aperture 40, there are a pair
of opposed openings 47 and 48 in the side walls of throat section
44. The portion of these openings exposed to the atmosphere is
adjusted by means of a rotatable sleeve 49 mounted on the exterior
surface of throat section 44. Sleeve 49 is fixed in position by the
interengagement of annular rib 50 extending from the outer surface
of throat section 44 and recess 51 on the upper peripheral edge of
sleeve 49. In this manner, rotation of sleeve 49 about throat 44 is
permitted but axial movement is restricted. A circumferential
flange 52 extends from the upper portion of sleeve 49 and contains
indicia on the upper surface thereof which may be brought into
alignment with a pair of fixed diametrically opposed indicator
pointers 53. The particular alignment of indicia with pointers 53
will designate to the operator the percentage of oxygen in ratio to
outside air components other than oxygen in the mixing being
treated within chamber 43'.
The amount of outside air being mixed with the oxygen received
through tube 28 is adjusted by alignment between openings 47 and 48
in the throat section with openings 54 and 55 in the side walls of
sleeve 49. Each of the openings 54 and 55 in sleeve 49 are
substantially rectangular in configuration and are of similar size.
The openings 54 and 55 are approximately diametrically opposed as
are the openings 47 and 48 in throat section 44. Therefore, as will
be discussed in detail below by rotating sleeve 49 with respect to
fixed throat section 44, the relative percentage of openings 47 and
48 which are exposed to outside air through openings 54 and 55 can
be varied. Opening 47 in throat section 44 is substantially
rectangular in configuration and is approximately the same size as
openings 54 and 55 in sleeve 49. However, as shown particularly in
FIG. 4, opening 48 in throat section 54 includes three different
size interconnecting opening portions. The principal opening
portion 56 is substantially the same size and configuration as
openings 47, 54 and 55. Adjacent to opening portion 56 is an
interconnected opening portion 57 which is approximately
one-quarter the size of opening portion 56 and has a bottom wall 58
which tapers downwardly so that the end of opening portion 57
remote from opening portion 56 is smaller than the size of opening
portion 57 adjacent to opening portion 56. Additionally, opening
portion 59 is adjacent to opening portion 57 and communicates
therewith and has a bottom wall 60 which tapers downwardly toward
opening portion 57 so that opening portion 59 gets larger as it
approaches opening portion 57. Therefore, by rotating sleeve 49
with respect to throat section 44 in a counterclockwise direction
with the parts as shown in FIG. 4 so that opening 54 comes in
contact with opening 48, a greater and greater portion of opening
48 will be exposed as the rotation continues until opening 54 is
aligned with opening 48. In this position, as shown in FIG. 6,
openings 47 and 55 will also be aligned. Therefore, as shown in
FIGS. 5 and 6 with openings 47 and 55 in alignment and large
opening portion 56 in alignment with opening 54, the condition of
maximum openings to the exterior of chamber 43' is achieved and the
maximum amount of outside air to pure oxygen ratio is attained.
As shown in the embodiment depicted, in FIGS. 5 and 6, the
percentage of oxygen in the fluid mixture of outside air and pure
oxygen with maximum openings is 30 percent. FIGS. 7 and 8 depicts
the position of the sleeve 49 with respect to the throat 44 which
provides an oxygen percentage of 40 percent in the mixture. This
position is achieved by rotating the sleeve 49 clockwise until the
numerical indicia 40 is aligned with fixed pointers 53 on the top
of the throat section. It should be noted that to facilitate
rotation of sleeve 49 projections 61 are present on the exterior
surface of flange 52 so that it may be more easily gripped and
rotated. As shown, the 40 percent oxygen content is achieved by
reducing the size of the exposed openings to the exterior of device
20. By rotating sleeve 49 clockwise, opening portion 56 is
initially closed and smaller opening portions 57 and 59 of opening
48 are exposed. Thus, less opening space is available for outside
air to reach chamber 43.
Continued rotation of sleeve 49 in the clockwise direction will
bring the device into the position shown in FIGS. 9 and 10 where as
indicated 60 percent oxygen is present in the mixture within
chamber 43. In this position, the 60 percent indicia is aligned
with pointers 53 and opening 54 has been moved into alignment with
opening portion 59 only of throat section 44. Since opening 59 is
smaller than the previously discussed exposed openings, less
outside air is permitted into chamber 43 and a greater percentage
of oxygen is present. It should be kept in mind that in the
position discussed above in regard to FIGS. 7 and 8 openings 47 and
55 are almost completely not aligned so that virtually no outside
air is permitted access through opening 47. In the position shown
in FIGS. 9 and 10 openings 47 and 55 are in complete non-alignment
and no outside air can enter chamber 43' through opening 47. This
is true in regard to both of the two further positions discussed
below.
In the position depicted in FIGS. 11 and 12, sleeve 49 has been
rotated until the indicator pointers 53 are aligned with indicia
indicating 70 percent oxygen in the fluid mixture introduced to
chamber 43'. To reach this position, the sleeve has been rotated
clockwise until substantially all of opening 48 has been occluded
with the exception of approximately one half of opening portion 59.
This small opening is the only access port for outside air to be
mixed with the pure oxygen entering chamber 43' through tube
28.
Finally, in the position depicted in FIGS. 13 and 14, sleeve 49 has
been rotated until the indicator pointers 53 are aligned with
indicia indicating that 100 percent oxygen is being introduced into
chamber 43'. In this position, no portion of openings 47 and 48 are
aligned with openings 54 and 55 in sleeve 49 and, therefore, there
is no access port for outside air to enter chamer 43'.
It should be kept in mind that although five specific oxygen
percentage points are utilized in the depicted embodiment to
provide specific controls of oxygen percentage in the fluid mixture
introduced to the container, it can readily be seen that by varying
the dimensions of openings and by shifting the alignment position
of the openings of the sleeve with respect to the throat section,
other definite percentages can be obtained. Additionally, it should
be noted that clockwise rotation from the 30 to 100 percent
position will gradually decrease the amount of access opening
available in a continuous fashion so that intermediate points can
be estimated as desired.
In summary, with the type of nebulizer depicted and described
above, nozzle 37 and extension 42 thereof containing the gas 40 and
liquid 41 feed jets is positioned at the upper end of the vertical
cylindrical section of the throat 44. A larger cylindrical chamber
43' is fastened around the section of the nozzle containing the gas
and liquid feed jets. Resulting configuration provides for
efficient gathering and entraining of the air contained in the
larger upper cylinder 43', into the high velocity gas stream
escaping from gas jet 40. The lower cylindrical throat section or
collar 45 efficiently contains and directs the air, oxygen, liquid,
particle, aerosol mixture downward into container 21. As part of
its function, the throat completes a pressure envelope around the
high velocity gas, water, vapor stream and prevents the higher than
atmospheric pressure aerosol from escaping back up into the lower
than atmospheric pressure upper chamber. The above mentioned
function is an internal part of oxygen dilution control. As oxygen
supply flow is varied, the lower than atmospheric pressure in the
upper chamber must be automatically and proportionately varied to
provide for the proper amount of atmospheric air entrainment in
order to maintain the desired preset oxygen dilution.
Oxygen dilution refers to diluting the pure oxygen supply flow with
nominally 21 percent oxygen atmospheric air. The nebulizer permits
the user to select effluent gas oxygen concentrations between 30
through 100 percent. For convenience, concentration selection
points of 30, 40, 60, 70 and 100 are marked on the dilution
adjustment sleeve. The sleeve may be be affectively positioned at
any other setting within the 30 to 100 percent range and consistent
performance will be maintained.
Rotating the sleeve uncovers a pair of specially shaped apertures
in the upper chamber wall. These apertures are shaped to provide a
practical sleeve position difference between concentration
settings. For example, a long thin slot is uncovered for the 70 and
60 percent settings. Aperture height is nominally doubled between
60 and 40 percent. It is greatly increased and a second aperture
added between 40 and 30 percent oxygen concentration settings. The
system described above is directed to the only device of this type
with established calibrated presetable concentration control points
which also permits selection of concentration between the
established settings while maintaining a reasonable degree of
accuracy over the declared range of oxygen supply flow rates. This
result is obtained through employment of the combined mechanical
elements which provide the functions described above.
Thus, the above objectives of the invention, among others, are
effectively attained.
* * * * *