Fluidic oscillator with resonant inertance and dynamic compliance circuit

The fluidic oscillator consists of a resonant fluid circuit having a fluid inertance and a dynamic fluid compliance. The inertance is a conduit interconnecting two locations of a chamber on each side of a working fluid jet issuing into one end of the chamber, the inertance conduit serving to transfer working fluid between the two locations. Through one or more output orifices located approximately at the opposite end of the chamber, the fluid exits from a chamber exit region which is shaped to facilitate formation of a vortex (the dynamic compliance) from the entering fluid. The flow pattern in the chamber and particularly the vortex in the chamber exit region provide flow aspiration on one side and surplus of flow on the opposite side of the chamber, which effects accelerate and respectively decelerate the fluid in the inertance conduit such as to cause reversal of the vortex after a time delay given by the inertance. The vortex in the chamber exit region will thus cyclically alternate in velocity and direction of rotation to direct outflow through the output orifice such as to produce a cyclically repetitive side-to-side sweeping stream our spray pattern whose direction is determined, at any instant in time, as a function of the vectorial sum, at the output orifice, of the tangential vortex flow spin velocity vector and the static pressure vector as well as the dynamic pressure component, both directed radially from the vortex. By changing these parameters by suitable design measures and operating conditions and by appropriately configuring the oscillator, sweep angle, oscillation frequency, distribution, outflow velocity, break up into droplets, etc. can be readily controlled over large ranges.

BACKGROUND OF THE INVENTION 
The present invention relates to improvements in fluidic oscillators and 
particularly to a novel fluidic oscillator capable of providing a dynamic 
output flow of a broad range of properties which is obtainable by simple 
design variations and which can be further readily controlled during 
operation by appropriate adjustment means to achieve extensive performance 
flexibility, thus facilitating a wide variety of uses. 
Fluidic oscillators and their uses as fluidic circuit components are well 
known. Fluidic oscillators providing dynamic spray or flow patterns 
issuing into ambient environment have been utilized in such manner in: 
shower heads, as described in my U.S. Pat. No. 3,563,462; in lawn 
sprinklers, as described in U.S. Pat. No. 3,432,102; in decorative 
fountains, as described in U.S. Pat. No. 3,595,479; in oral irrigators and 
other cleaning apparatus, as described in U.S. Pat. No. 3,468,325; (also 
see U.S. Pat. Nos. 3,507,275 and 4,052,002, etc.). Most of these 
oscillators are constructed to produce outflow patterns which are suitable 
only for use in the specific apparatus for which they were designed and 
lack flexibility and adjustability for use in other applications. In most 
applications for prior art oscillators it has been found that performance 
is adversely affected by relatively small dimensional variations in the 
oscillator passages and chamber. It has also been found that most prior 
art oscillators require configurations of relatively large dimensions to 
satisfy particular performance requirements such that they are barred from 
many uses by practical size restrictions. Furthermore, most prior art 
oscillators have not had the capability for extensive in-operation 
adjustments of performance characteristics to fulfill numerous uses 
necessitating such adjustment capabilities. 
Many prior art fluidic devices, such as in U.S. Pat. Nos. 3,016,066 and 
3,266,508, have relied in operation on well established fluidic 
principles, such as the Coanda effect. It is, in my opinion, this reliance 
on such well-known effects which has brought about the aforementioned 
limitations and disadvantages. 
It is an object of the present invention to provide a fluidic oscillator 
which functions largely on different principles than previous fluidic 
oscillators and, therefore, overcomes the aforementioned limitations and 
disadvantages, and provides capabilities hitherto unavailable to meet 
application requirements for which prior art fluidic oscillators have not 
been suited. 
It is another object of the present invention to provide a fluidic 
oscillator whose outflow pattern performance can be varied over broad 
ranges by simple design measures. 
It is yet another object of the present invention to provide a fluidic 
oscillator which is relatively insensitive to dimensional manufacturing 
tolerances and dimensional variations resulting from its operation. 
It is a further object of the present invention to provide a fluidic 
oscillator of relatively small dimensions to meet practical size 
restrictions of many applications. For example, where as most prior art 
fluidic oscillators require, for satisfactory functioning, lengths, 
between the feed-in of supply fluid and the final outlet opening, of at 
least 10 (but more often 12 to 20 and in some cases as much as 30) times 
the respective supply feed-in nozzle widths, the present invention fluidic 
oscillator operates already with such relative lengths of as little as 5. 
Similarly, whereas most prior art fluidic oscillators require relative 
widths for the total channel configuration of at least 7 or more, the 
present invention oscillator configuration spans a relative width of 5 or 
less in many applications. One can readily appreciate the application 
advantages offered by such practical size reductions in the total 
oscillator configuration area to about one half or one third. 
It is yet another object of the present invention to provide a fluidic 
oscillator allowing and facilitating extensive adjustments of performance 
characteristics over broad ranges during operation. Oscillation frequency 
and angle of output flow sweep pattern and, therefore, also such dependent 
characteristics as waveform, dispersal distribution, velocity, etc. may be 
adjusted by simple means such that performance can be varied and adapted 
to changing requirements during operation. Furthermore, it is also an 
object of the present invention to provide a fluidic oscillator whose 
performance may be adjusted or modulated continuously in the 
aforementioned characteristics by externally applied fluid control flow 
pressure signals. By way of an example, tests have been performed with 
experimental models of fluidic oscillators of the present invention, which 
have shown a frequency adjustment range of over one octave and an output 
sweep angle adjustment range from almost zero degrees to over ninety 
degrees by application of an external fluid pressure flow to the 
oscillator control input connection with control pressure ranging between 
zero gage (no control flow) and the same pressures as supplied to the 
oscillator fluid power input. Additionally, inertance adjustments of the 
fluid inertance conduit of the oscillator have shown practical continuous 
control over oscillation frequency during operation over several octaves. 
It is still another object of the present invention to provide arrays of 
two or more similar fluidic oscillators capable of being accurately 
synchronized with each other in any desired phase relationship by means of 
appropriate simple fluid conduit interconnections between such 
oscillators. 
It is further an object of the present invention to provide fluidic 
oscillators for use in shower heads to provide dispersal of water flow 
into suitable spray and/or massaging and improved cleansing effects due to 
the cyclically repetitive flow impact forces on body surfaces, to further 
provide shower heads including fluidic oscillators for the aforementioned 
purposes, wherein oscillation frequency and spray angle are adjustable 
over broad ranges, and wherein the oscillators, if more than one are used, 
are synchronized with each other, and wherein manual controls are provided 
for such adjustments, and wherein the shower head has manually settable 
valving means for the mode selection of conventional steady spray or 
oscillator generated spray and massaging effects or any combination 
thereof. 
SUMMARY OF THE INVENTION 
The invention concerns a fluidic oscillator for use in dispersal of 
liquids, in mixing of gases, and in the application of cyclically 
repetitive momentum or pressure forces to various materials, structures of 
materials, and to living body tissue surfaces for therapeutic massaging 
and cleansing purposes. 
The fluidic oscillator consists of a chamber, a fluid inertance conduit 
interconnecting two locations within the chamber, and a dynamic compliance 
downstream of these locations. A fluid jet is issued into the chamber from 
which the fluid exits through one or more small openings in form of one or 
more output streams, the exit direction of which changes angularly 
cyclically repetitively from side to side in accordance with the 
oscillation imposed within the chamber on the flow by the dynamic action 
of the flow itself. 
The fluid inertance conduit interconnects two chamber locations on each 
side of the issuing jet, and acts as a fluid transfer medium between these 
locations for fluid derived from the jet. The exit region of the chamber 
is shaped to facilitate formation of a vortex, which constitutes the 
dynamic compliance, such that the jet, in passing through the chamber, 
tends to promote and feed this vortex in a supportive manner in absence of 
any effect from the inertance conduit and, after the conduit's fluid 
inertance responds to the chamber-contained flow pattern influences, the 
jet will tend to oppose this vortex, will slow it down, and reverse its 
direction of rotation. The chamber-contained flow pattern, at one 
particular instant in time, consists of the jet issuing into the chamber, 
expanding somewhat, and forming a vortex in its exit region. In view of 
the continuous outflow of fluid from the periphery of the vortex through 
the small exit opening, the vortex would like to aspirate flow near the 
chamber wall on the side where the jet feeds into the vortex and it would 
like to surrender flow near the opposite chamber wall. Until the mass of 
the fluid contained in the inertance conduit, which interconnects the two 
sides of the chamber, is accelerated by these effects of the vortex on the 
chamber flow pattern, flow can be neither aspirated on one side nor 
surrendered on the other side, and the flow pattern sustains itself in 
this quasi-steady state. As soon as the fluid in the inertance conduit is 
accelerated sufficiently to feed the aspiration region and deplete the 
surrendering region, the flow pattern will cease to feed the vortex in the 
chamber exit region and the vortex will dissipate. Even though now the 
cause for the acceleration of the mass of fluid in the inertance conduit 
has ceased to exist, this mass of fluid continues to move due to its 
inertance and it is only gradually decelerating as its energy is consumed 
in first dissipating and them reversing the previous flow pattern state in 
the chamber to its symmetrically opposite state, at which time the mass of 
fluid in the inertance conduit will be accelerated in the opposite 
direction; after which the events continue cyclically and repetitively in 
the described manner. An outlet opening from the exit region of the 
chamber issues a fluid stream in a sweeping pattern determined, at the 
outlet opening, by the vectorial sum of a first vector, tangential to the 
exit region vortex and a function of the spin velocity, and a second 
vector, directed radially from the vortex and established by the static 
pressure in the chamber together with the dynamic pressure component 
directed radially from the vortex. By changing the average static pressure 
and the vortex spin velocity and their respective relationship by suitable 
design measures, the angle subtended by the sweeping spray can be 
controlled over a large range. By suitably configuring the oscillator, 
concentrations and distribution of fluid in the spray pattern can be 
readily controlled. By changing the inertance of the fluid inertance 
conduit, the oscillation frequency can be varied. By externally imposed 
pressurization of the chamber exit region, the oscillation frequency and 
the sweep angle can be readily controlled. Two or more oscillators can be 
synchronized together in any desired phase relationship by means of 
appropriate simple interconnections.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Specifically with reference to FIG. 1 of the accompanying drawings, an 
oscillator 14 is shown as a number of channels and cavities, etc., defined 
as recesses in upper plate 1, the recesses therein being sealed by cover 
plate 2, and a tubing or inertance conduit interconnection 4 between two 
bores 5 and 6 extending from the cavities through the upper plate 1. It is 
to be understood that the channels and cavities formed as recesses in 
plate 1 need not necessarily be two dimensional but may be of different 
depths at different locations, with stepped or gradual changes of depth 
from one location to another. For ease in reference, however, entirely 
planar elements are shown herein. It is also to be understood that, 
whereas a two-plate (i.e. plates 1 and 2) structure is implied in each of 
the embodiments, this is intended only to show one possible means of 
construction for the oscillator of the present invention. The invention 
itself resides in the various passages, channels, cavities, conduits, 
etc., regardless of the type of structure in which they are formed. The 
oscillator 14, as formed by recesses in plate 1 and sealed by plate 2, 
includes an upstream chamber region 3 which is generally of an 
approximately `U`-shaped outline, having an inlet opening 15 approximately 
in the center of the base of the `U`, which inlet opening 15 is the 
termination of inlet channel 9 directed into the upstream chamber region 
3. The open `U`-shaped upstream chamber region 3 reaches out to join the 
chamber exit region 11 which is generally again `U`-shaped, whereby the 
transition between the two chamber regions 3 and 11 is generally somewhat 
necked down in width near chamber wall transition sections 12 and 13, such 
that the combination in this embodiment may give the appearance of what 
one might loosely call an hour-glass shape. An outlet opening 10 from the 
base of the U-shaped chamber exit region 11 leads to the environment 
external to the structure housing the oscillator. Short channels 16a and 
16b lead in a generally upstream direction from the upstream chamber 
region 3 on either side of inlet opening 15 (from approximate corner 
regions 8 and 7) to bores 6 and 5, respectively. 
Operation of oscillator 14 is best illustrated in FIGS. 5 through 9. For 
purposes of the description herein, it is assumed that the working fluid 
is a liquid and that the liquid is being issued into an air environment; 
however, it is to be noted that the oscillator of the present invention 
operates as well with gaseous working fluids, and that any working fluid 
can be issued into the same or any other fluid environment. Upon receiving 
pressurized fluid through inlet opening 15, a fluid jet is issued and 
flows through upstream chamber region 3 and chamber exit region 11 and 
egresses through output opening 10, as shown in FIG. 5. However, as a 
consequence of the expansion of the fluid jet during its transition 
through chamber regions 3 and 11 and a certain loss of cohesiveness of the 
jet due to shear effects some portions of its flow are peeled off before 
egressing through opening 10, and such portions of flow quickly fill voids 
in the chamber cavities as well as filling the inertance conduit 
interconnection 4, as further indicated in FIG. 5. Asymmetries inherent in 
any structure and asymmetries inherent in the portions of peeled-off flow 
on either side of the jet ensure that complete filling occurs, for all 
practical purposes, almost instantaneously. The same aforementioned 
inherent asymmetries will cause more flow to be peeled back on one side of 
the jet than on the other side, which will necessarily cause the jet to 
veer into a vortex flow pattern tending toward the pattern indicated in 
the chamber exit region 11 of FIG. 6 (or its symmetrically opposite 
pattern). The tendency of the jet to veer off into the vortex pattern in 
FIG. 6 is supported and reinforced by the increasingly larger amount of 
peeled off flow due to the more angled approach of the jet to outlet 
opening 10. Opposed to this tendency is the jet flow momentum which acts 
toward a straightening of the jet. A mutual balance of these influences on 
the jet is necessarily reached before the jet can deflect completely 
toward the respective side of the chamber exit region 11. By the inherent 
nature of this flow pattern, a powerful aspiration region establishes 
itself in the approximate area where the jet flow enters the vortex near 
the transition between chamber regions 3 and 11 on the opposite side of 
the jet to the center of the vortex, and the vortex would like to 
surrender flow on its side of the jet. The only path which can permit an 
exchange of flow between this aspirating region and the surrendering 
region is along both sides of the jet in an upstream direction through the 
sides of upstream chamber region 3 and via inertance conduit 
interconnection 4. However, as the inertance conduit interconnection 4 
represents a significant inertance and thus an impedance to flow changes 
by virtue of its physical design, the mass of fluid contained within this 
conduit interconnection 4 and within the remainder of this path between 
the aspirating and surrending regions has to be accelerated before a flow 
between these two regions may influence and change the described 
quasi-steady state flow pattern shown in FIG. 6. As soon as the flow in 
inertance conduit connection 4 is accelerated sufficiently to feed the 
aspiration region and deplete the surrendering region, the previously 
established flow pattern will gradually cease to feed the vortex in 
chamber exit region 11 and the vortex will dissipate, as indicated in FIG. 
7. Even though now the cause for the acceleration of the mass of fluid 
within inertance conduit interconnection 4 has ceased to exist, this mass 
of fluid continues to move due to its inertance and it will only gradually 
decelerate as its dynamic energy is consumed in first dissipating and 
later gradually reversing the previous flow pattern state in the chamber 
to its symmetrically opposite state, as indicated in FIGS. 8 and 9, after 
which this mass of fluid in the inertance conduit connection will begin to 
be accelerated in the opposite direction; thereafter, the sequence of 
events continues cyclically and repetitively in the described manner. The 
sequence of events depicted in FIGS. 6, 7, 8 and 9 (in this order), and as 
described above, represents flow pattern states and their changes at 
various times within one half of an oscillation cycle. In order to 
visualize the events of the second half cycle of the oscillation, one need 
only symmetrically reverse all depicted flow patterns, starting with the 
one shown in FIG. 6 and continuing through FIGS. 7, 8 and 9. 
It should perhaps be mentioned here that, whereas the inertance effect of 
inertance conduit 4 is clearly analogous to an electrical inductance L, 
the effect of a reversing vortex spin within a confined flow pattern, as 
occuring within the oscillator of the present invention, may be considered 
to represent a dynamic compliance (even when operating with incompressible 
fluids), and it provides an analogous effect not unlike the one of an 
electrical capacitance C. From the preceding descriptions, one can readily 
visualize the alternating energy exchange between the inertance of the 
fluid in the inertance conduit interconnection and the dynamic compliance 
of the vortex flow pattern to be somewhat analogous to the mechanism of a 
resonant electrical inductance/capacitance (LC) oscillator circuit. 
As a consequence of the aforementioned alternating vortical flow pattern in 
chamber exit region 11, flow egresses through output opening 10 in a 
side-to-side sweeping pattern determined, at the output opening, by the 
vectorial sum of a first vector, tangential to the exit region vortex and 
a function of the spin velocity, and a second vector, directed radially 
from the vortex and established by the static pressure in chamber exit 
region 11 together with the dynamic pressure component directed radially 
from the vortex at output opening 10. A resulting typical output flow 
pattern 16 is shown diagrammatically in FIG. 4. It can be seen, in FIG. 4, 
that this output flow pattern 16 takes on a sinusoidal shape, wherein the 
wave amplitude increases with downstream distance. Since the shown pattern 
16 represents the state in one instant of time, one must visualize the 
actual dynamic situation; the wave of pattern 16 travels away from the 
output opening 10 as it expands in amplitude subtending angle .alpha.. 
Referring to FIG. 2, the shown oscillator 17 is represented with only the 
plate 18 within which the recesses forming the oscillator's channels and 
cavities are contained, the cover plate being removed for purposes of 
simplification and clarity of description. In fact, for most of the 
oscillators shown and described hereinbelow, the cover plate has been 
removed for these purposes. Oscillator 17 includes an inlet opening 19 
similar to inlet opening 15 of FIG. 1 and an inertance conduit 20 similar 
to inertance conduit interconnection 4 of FIG. 1, except that the latter 
is in form of a tubing interconnection external to the oscillator upper 
plate 1 of FIG. 1 and the former is in form of a channel interconnection 
shaped within plate 18 of FIG. 2 itself. Inlet passage and hole 21 
corresponds to inlet channel 9 of FIG. 1. An upstream chamber region 22 
and a chamber exit region 23 correspond to upstream chamber region 3 and 
chamber exit region 11 in FIG. 1, respectively, except that the chamber 
wall transition sections 23 and 24, corresponding to sections 12 and 13 of 
FIG. 1, are inwardly curved in a downstream direction until they meet with 
sharply inwardly pointed wall sections 25 and 26 which lead to output 
opening 10 (same as output opening 10 in FIG. 1). Chamber exit region 23, 
even though of slightly different shape to the corresponding region 11 of 
FIG. 1, serves the same purpose as described before. Whereas the necked 
down transition between regions 3 and 11 of FIG. 1 provides certain 
performance features under certain specific operating conditions, the 
inwardly curved wall transition of wall sections 23 and 24 of FIG. 2 
provide other performance features under different operating conditions 
without changes in fundamental function of the oscillator, already 
described in relation to FIG. 1. For example, the chamber regions 22 and 
23 cause the output spray pattern to provide smaller droplets (among other 
features) than the hourglass shape of the corresponding regions of FIG. 1. 
Inertance conduit 20, being within plate 18, does not affect the 
oscillation differently to inertance conduit 4 of FIG. 1, except insofar 
as a different inertance results due to different physical dimensions. 
Fundamentally, the inertance is a function of the contained fluid density 
and it is proportional to length of the conduit and inversely proportional 
to its cross-sectional area. Consequently, longer conduits and/or conduits 
with smaller cross-sectional areas provide larger inertances and thus 
cause lower oscillation frequencies of the oscillator. 
Referring to FIG. 3, an oscillator 27 is again represented with only the 
plate 28 within which the recesses forming the oscillator's channels and 
cavities are contained, depicted as such for the same reason as already 
described in relation to FIG. 2. The oscillator 27 of FIG. 3 has the same 
general configuration shape as shown for oscillator 17 of FIG. 2, except 
that the inertance conduit 29 takes a circular path and chamber regions 30 
and 31 define a more smoothed out wall outline even more inwardly curved 
and already beginning its curvature approximate to both ends of inertance 
conduit 29. As discussed in relation to FIG. 2, different layouts of 
inertance conduits have no bearing on the fundamental oscillator 
operation, yet the flexibility of layout provides distinct advantages in 
design and construction of actual products comprising the oscillator of 
the present invention, and it is a particular purpose of FIGS. 1, 2, 3, 
and 4 to show such flexibility. Oscillator 27 of FIG. 3, in view of its 
discussed more inwardly curved smoothed out chamber wall outline, in 
comparison with oscillator 17 of FIG. 2, provides certain different 
performance characteristics, for example narrower spray output angles, 
more cohesive output flow with larger droplets in a narrower range of size 
distribution, etc. The fundamental function and operation of oscillator 27 
is the same as already described in relation with the oscillator 14 of 
FIG. 1. 
Referring specifically to FIG. 4, an oscillator 32 is represented with only 
the plate 33 within which the recesses forming the oscillator's channels 
and cavities are contained, depicted as such for the same reason as 
already described in relation to FIG. 2. Oscillator 32 has the same 
general configuration and shape as shown for oscillator 14 of FIG. 1, 
except that the inertance conduit 34 is shaped similarly to inertance 
conduit 29 of FIG. 3 and that it is also contained as a recess within 
plate 33, corresponding to the construction shown in FIG. 3, and that 
inertance conduit 34 is laid out in a very short path, the effect of which 
is an increase in oscillation frequency for reasons already discussed in 
relation to FIG. 2. Chamber region 35 is simply adapted in its width near 
inlet opening 19 to mate its walls with the outer walls of the ends of 
inertance conduit 34, which has no bearing on the general function and 
operation of the oscillator 32 as distinct from oscillator 14, 17, and 27 
(FIGS. 1, 2, and 3, respectively). Chamber exit region 36 corresponds to 
chamber exit region 11 of FIG. 1 in configuration and function. In 
comparison with, for example, the configuration of oscillator 27 of FIG. 
3, the chamber shape, particularly the wider and generally larger exit 
region 36 of FIG. 4, will cause different performance characteristics; for 
example, wider spray output angles .alpha., still more cohesive output 
flow with narrower size distributions of droplets, smoother output 
waveforms of more sinusoidal character, etc. A typical output waveform 
applicable in general to all the oscillators of the present invention is 
diagrammatically shown as the output flow pattern 16 of FIG. 4. The 
fundamental function and operation of oscillator 32 of FIG. 4 is the same 
as already described in relation with oscillator 14 of FIG. 1. 
It is to be noted, with respect to the effects of relatively gross changes 
of inertances of the inertance conduits in relation to particularly the 
width and length dimensions of chamber exit regions, that definite 
performance tendencies have been experimentally verified, as indicated in 
the following: Very high relative inertances cause output waveforms to 
take on more and more trapezoidal characteristics. Gradually reduced 
relative inertances cause output waveforms to approach and eventually 
attain a sinusoidal character. And further relative reductions in 
inertance cause sharpening of wavepeaks whereby waveforms eventually 
attain triangular shapes. Additional relative inertance reductions result 
in little, if any, additional wave shape changes but they cause gradual 
sweep or spray angle reductions (which up to this point remain virtually 
constant with inertance changes). Naturally, oscillation frequencies 
changed during these experiments in accordance with the different 
relationship between applicable characteristic oscillator parameters and 
employed inertances. 
Design control over output waveforms is an important aspect of the present 
invention since the output waveform largely establishes the spray flow 
distribution or droplet density distribution across the output spray angle 
and different requirements apply to different products and uses. For 
example, trapezoidal waveforms generally provide higher densities at 
extremes of the sweep angle than elsewhere. Sinusoidal waveforms still 
provide somewhat uneven distributions with higher densities at extremes of 
the sweep angle and usually lower densities near the center. Triangular 
waveforms generally offer even distribution across the sweep angle. 
Referring to FIG. 10, an oscillator of the general type illustrated in FIG. 
1 is modified by replacing output opening 10 of FIG. 1 with three output 
openings 37, 38, and 39 located in the same general area. In fact, any 
number of output openings may be provided along the frontal (output) 
periphery of chamber exit regions at any desired spacings and of same or 
different sizes. Output openings 37, 38, and 39 in FIG. 10 will each issue 
an output flow pattern which will exhibit the same characteristics as 
described in detail in relation to FIGS. 1 or 4. The sweep angles of the 
multiple output flow patterns may be separated or they may overlap, as 
required by performance needs. Waveforms will be of generally identical 
phase relationship (and frequency). Inertance conduit interconnection 40 
is shown to interconnect areas 41 and 42 directly without employment of 
intermediate channels such as ones shown in FIG. 1 as short channels 16 
and 17. This variation is shown purely to indicate another design option 
possible when size and other construction criteria allow or impose such 
differences, and it does not affect the fundamental function and operation 
of the oscillator shown in FIG. 10, which is the same as already described 
in relation with the oscillator 14 of FIG. 1. The purpose for multiple 
output openings in oscillators, as illustrated in FIG. 10, is to be able 
to obtain different output spray characteristics; for example, different 
distributions, spray angles, smaller droplet sizes, low spray impact 
forces, several widely separated spray output patterns, etc. 
Referring to FIG. 11, an oscillator of the general type illustrated in FIG. 
1 is modified by provision of an opening 43 into the chamber exit region 
44, by employment of an inlet opening and an inlet hole 47 like inlet 
opening 19 and inlet passage and hole 21, both in FIG. 2, and by 
utilization of an adjustable length inertance conduit interconnection 45. 
FIG. 11 shows further fluid supply connections to the inlet hole 47 as 
well as to opening 43, both leading from valving means 46, represented in 
block form. The oscillator of the arrangement in FIG. 11, operating in the 
same way as oscillator 14 of FIG. 1, upon receiving pressurized fluid 
through opening 47, is not affected by the presence of opening 43 as long 
as the feed to opening 43 is closed off, and it is not affected by the 
presence of the adjustable length inertance conduit interconnection 45, 
except to the extent that the oscillation frequency will change as a 
function of a change in length of interconnection 45. The oscillation 
frequency can be further changed by adjustment of valving means 46 in 
admitting pressurized fluid through opening 43 into region 44. Such 
admittance of fluid is of relatively low flow velocities and generally 
does not affect the fundamental flow pattern events in region 44. However, 
as pressure is increased to opening 43, predominantly the static pressure 
increases in region 44, and also in the remainder of the oscillator. This 
has two main effects: For one, the supply flow through opening 47 will be 
reduced due to the backpressure increase experienced, and consequently the 
oscillation frequency will be reduced, as the jet velocity reduces also; 
and secondly, the static pressure increases particularly in region 44. A 
change in the vectorial sum, at the oscillator output opening, of the 
various velocities, described in detail in relation to the operation of 
the oscillator embodiment shown in FIG. 1, such that the second vector 
which is directed radially from the vortex increases in relation to the 
first vector which is tangential to the exit region vortex, and 
consequently the output flow sweep angle decreases. Thus one can see that 
an adjustment of pressure supplied to opening 43 changes oscillation 
frequency and output flow sweep angle. At the same time, only minimal 
total flow rate changes for the oscillator are experienced, because 
pressurization of region 44 via opening 43 and the inflow of additional 
fluid caused thereby through opening 43 is to some extent compensated by 
the concomitant decrease in supply flow through inlet hole 47. Pressure 
adjustment by way of valving means 46 may be applied exclusively to 
opening 43, whilst holding pressure to inlet hole 47 constant, or both 
pressure supplies may be independently adjusted, or both pressures may be 
adjusted by valving arrangements ganged together in any desired 
relationship. Furthermore, the pressure (and flow) input into opening 43 
may be fed from any suitable source of fluid, for example one which will 
provide a time or event dependent variation in pressure such as to control 
or modulate the oscillator onput as a function thereof. Experimental 
results have shown practical a frequency adjustment range of over one 
octave and an output sweep angle adjustment range from almost zero degrees 
to over ninety degrees without exceeding the supply pressure to inlet hole 
47 by the adjustment pressure to opening 43. In addition to the 
performance adjustments afforded by the aforementioned means, oscillation 
frequency is independently adjustable by means of length adjustment of the 
adjustable length inertance conduit interconnection 45, which is simply an 
arrangement similar to the slide of a trombone, whereby the length of the 
conduit may be continuously varied. Experiments have shown practical 
adjustment ranges up to several octaves employing such an arrangement. It 
is feasible to provide valving arrangements ganged to adjust not only the 
pressures to opening 43 and to inlet hole 47 but also mechanically coupled 
to adjust the length of inertance conduit interconnection 45 with a single 
control means, such that, for example, a single manually rotatable knob 
causes an oscillator output performance change over a further extended 
very wide range. The aforementioned performance adjustment capabilities 
are particularly useful in processes where in-operation requirements vary. 
In other applications, adjustability is needed to adapt performance to 
subjective requirements; for example, oscillators employed in massaging 
shower heads for therapentic or simply recreational purposes would exhibit 
particularly advantageous appeal if their effects were capable to be 
adjusted to a wide range of individual subjective needs and desires. 
Referring to FIGS. 12 and 13, a compact adjustment means for varying the 
inertance of the inertance conduit interconnection of any of the 
oscillators shown in FIGS. 1 through 11 and 14 is illustrated. A 
cylindrical piston 47a is axially movably arranged within a cylindrically 
hollow body 48, wherein piston 47a is peripherally sealed by seal 49. A 
portion of the body 48 is of a somewhat larger internal diameter than 
piston 47a, such that an annular cylindrical void 48a is formed between 
piston 47a and body 48 when piston 47a is fully moved into body 48, and 
such that, in a partially moved-in position of piston 47a, a partially 
annular and partially cylindrical void is formed, and such that a 
cylindrical void is formed when piston 47a is withdrawn further. The 
internal peripheral wall of the cylindrical hollow body 48 has two conduit 
connections in proximity to each other and oriented approximately 
tangentially to the internal cylindrical periphery, wherein the conduit 
entries point away from each other. The conduits lead to interconnection 
terminals 50 and 51, respectively. Since the inertance between the two 
terminals 50 and 51 is a proportional function of the length and an 
inversely proportional function of the cross-sectional area of the path a 
fluid flow would be forced to take when passing between terminals 50 and 
51 through the means shown in FIGS. 12 and 13, it can be shown that the 
inertance of this path is continuously varied as piston 47a is moved in 
body 48 and as the internal void changes shape and volume between one 
extreme of a cylindrical annulus, when highest inertance is obtained, and 
the other extreme of a cylinder, when lowest inertance is reached. In 
comparison with the variable inertance conduit interconnection 45 of FIG. 
11, the arrangement of FIGS. 12 and 13 offers compactness, simpler 
sealing, and a less critical construction. Replacing the slide of 
interconnection 45 of FIG. 11 with the arrangement of FIGS. 12 and 13 by 
connecting terminals 50 and 51 respectively to the two conduit stubs 
opened up by the removal of interconnection 45, all operation and 
adjustment described in relation to FIG. 11 applies. 
Referring to FIG. 14, two oscillators of the general type illustrated in 
FIG. 1 are interconnected by suitable synchronizing conduits 52 and 53 
between symmetrically positioned locations of the respective inertance 
conduit interconnections, particularly between such locations in proximity 
to the chamber entries 54, 55, 56, and 57 of the inertance conduit 
interconnections. Conduit 52 connects entry 54 with entry 57 and conduit 
53 connects entry 55 with entry 56. The two oscillators in the shown 
connection will oscillate in synchronism, provided they are both of a like 
design to operate at approximately the same frequencies if supplied with 
the same pressure, and their relative phase relationship will be 180 
degrees apart when viewed as drawn. Interchanging the connections of two 
entries only at one oscillator, for example re-connecting conduit 52 to 
entry 55 and conduit 53 to entry 54 will provide an in-phase relationship. 
Different lengths and unequal lengths of conduits 52 and 53, as well as 
changes of the connecting locations of synchronizing conduits along the 
inertance conduit interconnections result in a variety of different phase 
relationships. It is also feasible to thusly interconnect unlike 
oscillators to provide slaving at harmonic frequencies. More than two 
oscillators may be interconnected and synchronized in like manner and such 
arrays may be interconnected to provide different phase relationships 
between different oscillators. Furthermore, series interconnections 
between plural oscillators may be employed, wherein synchronizing conduits 
can be employed to provide the inertance previously supplied by the 
inertance conduit interconnections and wherein individual oscillator's 
inertance conduit interconnections may be omitted. 
Referring to FIG. 15, a typical hand-held massaging shower head is 
illustrated to contain two synchronized oscillators of the general type 
shown in FIG. 1, interconnected by an arrangement as indicated in FIG. 14, 
and equipped with variable performance adjustment arrangements generally 
described in relation to FIG. 11 and FIGS. 12 and 13. The shower head is 
supplied with water under pressure through hose 58 and it commonly 
contains valving means for the mode selection between conventional steady 
spray and massaging action. Manual controls 59 and 60 are arranged such as 
to advantageously provide not only mode selection control but also the 
adjustment control for frequency and sweep angle (as described in relation 
to FIG. 11, by means of the pressure adjustment to opening 43 and/or by 
ganged or combined pressure adjustment to supply hole 47), all the 
preceding adjustment controls and the mode selection being preferably 
arranged in one of the two manual controls 59 or 60, and to provide the 
independent frequency adjustment (as described in relation to FIGS. 11, 12 
and 13, by means of the inertance adjustment of inertance conduit 
interconnection 45 or by means of the arrangement shown in FIGS. 12 and 
13) in the other of the two manual controls 59 or 60. The gauged or 
combined mode selection and frequency and sweep angle control may be a 
valving arrangement which allows supply water passage only to the 
conventional steady spray nozzles when the manual control is in an extreme 
position. When the manual control is rotated by a certain angle, the 
valving arrangement permits supply water passage also to the supply inputs 
of the oscillators and on further control rotation, water passage is 
allowed only to the supply inlets of the oscillators. Yet additional 
rotation of the manual control will reduce the frequency and sweep angle 
by adjustment of the respective pressures to the oscillators. The 
independent frequency adjustment is a mechanical arrangement facilitating 
the translational motion needed to the respective inertance conduit 
interconnection adjustment described earlier in detail. Thus for example, 
the respective manual control 59 or 60 may be adjusted by rotation between 
two extreme positions whilst the oscillation frequency changes between 
corresponding values. It should be noted here that the frequency 
ajdustments bear such a relationship with respect to each other that the 
frequency range ratio of one is approximately multiplied by the frequency 
range ratio of the other to obtain the total combined frequency range, 
which is, therefore, greatly expanded due to the two control adjustments. 
In FIG. 16 there is illustrated an application of the oscillator of the 
present invention in a shower or spray booth (or shower or spray tunnel), 
wherein a plurality of oscillators in form of identical nozzles 61 is 
arranged and mounted in various locations along a liquid supply conduit 62 
which feeds liquid under pressure to each nozzle 61. Conduit 62 is shaped 
along its length into a door-outline or any appropriate form for the 
particular application. Nozzles 61 are oriented inwardly such as to 
provide overlapping spray patterns. Nozzles 61 are preferably oriented 
with the plane of their spray patterns in the plane defined by the shape 
of supply conduit 62. It is the purpose of such an arrangement to provide 
large spray area coverage with minimal flow consumption, for example in 
shower booths or in spray booths, wherein one or more such arrangements 
may be installed. The oscillator nozzles of the present invention not only 
are capable of providing the large area coverage with relatively fine 
spray at minimal flow consumption, but they provide additional advantages, 
in arrangements as shown in FIG. 16, of being much less liable to clogging 
in comparison with conventionally utilized steady stream or spray nozzles 
due to the latter's small flow openings in relation to the much larger 
oscillator channels. Furthermore, for equal effect, orders of magnitude 
larger numbers of conventional nozzles are needed than the few wide angle 
spray nozzles required to provide the same coverage. 
While I have described and illustrated various specific embodiments of my 
invention, it will be clear that variations from the details of 
construction which are specifically illustrated and described may be 
resorted to without departing from the true spirit and scope of the 
invention as defined in the appended claims.