WO1979000361A1

WO1979000361A1 - Improved fluidic oscillator and spray-forming output chamber

Info

Publication number: WO1979000361A1
Application number: PCT/US1978/000195
Authority: WO
Inventors: P Bauer
Original assignee: P Bauer
Priority date: 1977-12-09
Filing date: 1978-12-07
Publication date: 1979-06-28
Also published as: JPS54500111A; JPH0246802B2

Abstract

A fluidic oscillator includes a chamber (13) having a common inflow and outflow opening (14) into which a jet is issued in a generally radial direction. After impinging upon the far chamber wall the jet is redirected to form a vortex A, B on each side of the incoming jet. The vortices alternate in strength and position to direct outflow through the common opening along one side and then the other of the inflowing jet. A spray-forming output chamber (37) is arranged to receive the pulsating outflows from the aforementioned or other fluid oscillator and establish an output vortex which is thereby alternately spun in opposite directions. An outlet opening (38) from the output chamber issues fluid in a sweeping spray pattern determined by the vectorial sum of a first vector, tangential to the output vortex and a function of the spin velocity, and a second vector, directed radially from the vortex and determined by the static pressure in the chamber. By increasing or decreasing the static pressure, or by increasing or decreasing the vortex spin velocity, the angle subtended by the sweeping spray can be controlled over an unusually large range. By properly configuring the oscillator and/or output chamber, concentrations and distribution of fluid in the spray pattern can be readily controlled.

Description

IMPROVED FLUIDIC OSCILLATOR AND SPRAY-FORMING OUTPUT CHAMBER

TECHNICAL FIELD

The present invention relates to improvements in fluidic oscillators and to a novel spray-forming output chamber for fluidic oscillators. BACKGROUND ART

It has been recognized in the prior art that fluidic oscillators can serve not only as fluidic circuit components but also as fluid distribution or spray devices. (See U. S. Patents Numbers 3,432,102; 3,507,275; 4,052,002). In all of these patents a fluid jet is caused to oscillate by means of fluid interaction using no moving parts, and the resulting oscillating jet is issued into the ambient environment to disburse the fluid therein. Other fluidic oscillators, such as described in U. S. Patent No. 3,563,462, issue discrete pulses of fluid in alternation from two or more spray openings. In most applications for prior art fluidic oscillators it has been found that oscillator performance is dramatically affected by relatively small dimensional variations in the oscillator passages and chamber. It has also been found that prior art oscillators are extremely sensitive to properties of the sprayed fluid, such as viscosity, surface tension, temperature, etc.

Another concern with prior art oscillators, particularly when employed to achieve specific spray patterns, is that the desired spray patterns are not achieved immediately upon start up. Generally, the desired spray pattern is achieved only after the oscillator is substantially filled with the spray fluid; however, until the oscillator is filled it is quite common for a nonoscillating jet to issue from the device.

Prior art fluidic devices have been designed to operate in accordance with well established fluidic principles, such as

Coanda effect, stream momemtum exchange effects, and static pressure control effects. It is, in my opinion, this reliance upon these standard fluidic effects which brings about the aforementioned limitations and disadvantages. It is an object of the present invention to provide a fluidic oscillator which operates on a different principle than previous fluidic oscillators and, thereby, is not shackled with the aforementioned disadvantages. It is another object of the present invention to provide a fluidic oscillator which is relatively insensitive to dimensional manufacturing tolerances.

It is yet another object of the present invention to provide a fluidic oscillator having improved operating characteristics over large ranges of variations of operating fluid properties and thereby offer wider application capabilities than prior art fluidic oscillators.

An important aspect of fluidic oscillators, when utilized as spray or fluid dispersal devices, is the waveshape of the issued or dispersal pattern. Depending upon the desired distribution characteristics, the waveshape must be tailored accordingly. For example, as described in the aforementioned U. S. Patent No. 4,052,002, relatively uniform spatial distribution of the fluid is achieved if the waveform is triangular with little or no dwell time at the extremes of the fan-shaped sweep. As more dwell time is introduced in the extremes of the sweep, spatial distribution becomes more dense at the extremes and less dense at the center. To achieve higher densities at the center, or between the center and extremes of the sweep is difficult. Moreover, to tailor the sweep pattern to achieve many desired spatial distributions is difficult in the prior art oscillators.

Further, droplet size, in the case of liquids sprayed from prior art fluidic oscillators, is an important consideration in two respects. First, specific droplet sizes are required for different spray applications. Second, certain droplet sizes have been found to be dangerous to inhale and must be avoided. In prior art fluidic oscillators, the size of the oscillator pretty much, determines the range of droplet sizes in the issued spray pattern. Often it occurs that a particular oscillator size is necessary to achieve the desired droplet size, but that such oscillator size is impractical for that application because of space requirements.

Still another important characteristic of spray and dispersal patterns from fluidic oscillators is the sweep frequency. Again, this characteristic is determined by the oscillator size in prior art fluidic oscillators. An example of one frequency require ment would be in a massaging shower wherein the frequency should be such as to provide a massaging effect, or in an oral irrigator wherein a massaging effect is likewise desirable. On the other hand, when the oscillator is used as a nozzle for hair spray or anti-perspirant it is desirable that no massaging effect be felt. As described in the case of droplet sizes above, it often occurs that an oscillator size which is suitable for achieving the desired sweep frequency is not satisfactory for the space requirement of the overall device.

It is therefore an object of the present invention to provide an improvement for fluidic oscillators which permits control over the spray pattern, droplet distribution, droplet size and sweep frequency of issued fluid. It is another object of the present invention to provide an output region, useful with any fluidic oscillator, which permits considerable variation in the spray pattern and characteristics of oscillators of specified sizes.

It is still another object of the present invention to provide an output region for a fluidic oscillator which employs an entirely novel principle of spray formation and thereby permits control of the angle, frequency, droplet size and distribution of the issued spray pattern.

DISCLOSURE OF INVENTION In accordance with the present invention a fluidic oscillator includes a chamber having a common inlet and outlet opening through which a fluid jet is issued across the chamber. Upon impacting the far wall of the chamber the jet forms two oppositely rotating vortices, one on either side of the jet, which alternate in strength and position in opposite phases in the chamber. Each vortex alternately conducts more or less fluid out of the common opening on its side of the jet. The alternating outflows may be issued as fluid pulses for a specific utilization or may be used in conjunction with the output chamber described below to achieve a desired spray pattern. Still another utilization of the oscillator is as a flow meter whereby the oscillator is disposed in a flow path and its oscillation frequency is measured to provide a linear function of flow. This configuration has been found to be relatively insensitive to dimensional manufacturing tolerance variations, and operates over a wide range of fluid characteristics.

In accordance with another aspect of the present invention an output chamber for a fluidic oscillator receives fluid pulses in alternating opposed rotational directions. An output vortex is established in the output chamber and is alternately spun in opposite directions by the alternating input pulses. One or more outlet openings at the periphery of the output chamber issue a sweeping spray that is determined by the vectorial sum of two flow components: a first component is directed tangential to the output vortex and has a magnitude proportional to the instantaneous flow velocity at the output vortex periphery; a second component is directed generally radially outward from the output vortex and is a function of the static pressure at the vortex periphery and the net flow rate into the output chamber. By reducing the static pressure in the chamber, for example by making the outlet opening wider or reducing the inflow, the frequency, droplet size and spray angle can be selected accordingly. By contouring the chamber walls, the fluid distribution with the spray pattern can be selected. BRIEF DESCRIPTION OF THE DRAWINGS

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings, wherein: Figure 1 is top view in section, taken along lines 1 - 1 of Figure 2, showing the bottom plate of a fluidic oscillator constructed in accordance with the present invention;

Figure 2 is an end view in section taken along lines 2 -2 of Figure 1;

Figure 3 is a side view in section taken along lines 3 -3 of Figure 1;

Figure 4 is a top view in plan of the bottom plate of another fluidic oscillator of the present invention combined with an input chamber according to the present invention;

Figure 5 is a top view in plan of the bottom plate of another fluidic oscillator/output chamber combination of the present invention;

Figure 6 is a top view in plan of the bottom plate of another fluidic oscillator according to the present invention;

Figure 7 is a side view in section taken along lines 7 -7 of Figure 6;

Figure 8 is a top view in plan of the bottom plate of a conventional fluidic oscillator combined with the output chamber of the present invention;

Figure 9 is a top view in plan of the bottom plate of an output chamber of the present invention combined with schematically represented source of alternating fluid pulses;

Figure 10 is a diagrammatic representation of a typical waveform of a spray pattern issued from an output chamber of the present invention;

Figures 11, 12, 13, 14 and 15 are diagrammatic illustrations showing successive states of flow within a typical fluidic oscillator pf the present invention; Figure 16 is a diagrammatic illustration of the flow pattern associated with a typical single-outlet output chamber according to the present invention;

Figure 17 is a diagrammatic illustration of the flow pattern associated with a typical plural-outlet output chamber according to the present invention; Figure 18 is a diagrammatic representation of the waveform of the output sprays issued from the output chamber of Figure 17 ;

Figures 19 and 20 are top plan views of the bottom plate of respective oscillator/output chamber combinations of the present invention, illustrating diagrammatically the output waveforms associated therewith;

Figure 21 is a top plan view of the bottom plate of a fluidic oscillator/output chamber combination according to the present invention, showing relative dimensions of the various elements of the combinations;

Figure 22 is a diagrammatic illustration of the waveshape of alternating pulses issued from one oscillator embodiment of the present invention; Figure 23 is a diagrammatic illustration of the waveshape of alternating pulses issued from another oscillator embodiment of the present invention;

Figures 24, 25 and 26 are diagrammatic illustrations of the waveshapes of the spray patterns issued from three respective oscillator/output chamber combinations according to the present invention;

Figure 27 is a diagrammatic representation of the alternating pulse waveshapes issued from still another oscillator embodiment of the present invention; Figure 28 is a diagrammatic representation of the waveshape of a spray pattern issued from a combination of the oscillator of Figure 27 with an output chamber of the present invention;

Figure 29 is a diagrammatic illustration showing another embodiment of the oscillator/output chamber combination of the present invention and the waveform of the spray issued therefrom;

Figure 30 is a diagrammatic top plan view of another oscillator embodiment of the present invention;

Figures 31 and 32 are diagrammatic top plan and side section views, respectively, of another output chamber according to the present invention, showing the spray pattern issued therefrom;

Figures 33 and 34 are diagrammatic top plan and end section views, respectively, of another output chamber embodiment according to the present invention, showing the waveform of the spray pattern issued therefrom;

Figures 35 and 36 are diagrammatic top plan and side section views, respectively, of another output chamber embodiment of the present invention, showing the spray pattern issued therefrom;

Figure 37 is a diagrammatic plan view of an asymmetric oscillator/output chamber combination of the present invention;

Figures 38 and 39 are diagrammatic top plan and side section views, respectively, of another output chamber configuration according to the present invention;

Figures 40 and 41 are diagrammatic top plan and side section views, respectively, of another output chamber configuration according to the present invention;

Figures 42 and 43 are diagrammatic end and side views, respectively, of still another output chamber configuration according to the present invention;

Figures 44, 45, 46 and 47 are diagrammatic top plan views of four additional oscillator/output chamber combinations according to the present invention; Figures 48 and 49 are top section. and end views, respectively, of an oscillator of the present invention employed as a flow meter.

Figure 50 is a partially schematic top view in section of another flow meter embodiment of the present invention; Figure 51 is partially schematic top view in section of still another flow meter embodiment according to the present invention; and

Figure 52 is a side view in section of the flow meter of Figure 51. BEST MODE OF CARRYING OUT THE INVENTION Referring specifically to Figures 1, 2 and 3 of the accompanying drawings, a basic oscillator 10 is shown as a plurality of channels, cavities, etc., defined as recesses in a bottom plate 11, the recesses therein being sealed by cover plate 12. It is to be understood that the channels and cavities formed as recesses in plate 11 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 11 and 12) structure is illustrated in each of the embodiments, this is intended only to show one possible means of construction for the oscillator and output chamber of the present invention. The invention itself resides in the various passages, chambers, cavities, etc., regardless of the type of structure in which they are formed. The oscillator 10 as formed by recesses in plate 11 and sealed by plate 12 includes an oscillation chamber 13 which in this embodiment is generally circular, having an opening 14 along one side which, for example, may subtend an angle of approximately 90° on the circle. A passage extending to the end of plate 11 from opening 14 is divided into two outlet passages15 and 16 by a generally U-shaped member disposed therein. The U-shaped member has its open end facing chamber 13 and may be defined by means of recesses about member 17 in plate 11 or as a projection from cover plate 12 which abuts the bottom wall of the recess in plate 11. An inlet opening 18 is defined through the bottom of plate 11 within the confines of U-shaped member 17 and serves as a supply inlet for pressurized fluid. Opening 14 for chamber 13 serves as a common inlet and outlet opening for fluid in a manner described below.

Operation of oscillator 10 is best illustrated in Figures 11 through 15. 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 ambient environment; however, it is to be noted that the oscillator of the present invention and the output chamber of the present invention both operate with gaseous working fluids in gaseous environments, with liquid working fluids in liquid environments, and with suspended solid working fluids in gaseous environments. Upon receiving pressurized fluid through, inlet opening 18, member 17 directs a jet of the fluid through opening 14 into chamber 13. Upon impinging against the far wall of chamber 13, the jet divided into two oppositely directed flows which follow the contour of chamber 13 and egress through output passages 15 and 16 on opposite sides of the input jet and member 17. These two reversing flows form vortices A and B on opposite sides of the inflowing jet. This condition, which is illustrated in Figure 11, is highly unstable due to the mutual influences of the flow patterns on one another. Assume, for example, that as illustrated in Figure 12 the vortex B tends to predominate initially. Vortex B moves closer toward the center of chamber 13, directing more of the incoming fluid along its counter-clockwise flowing periphery and out of output passage 16. The weaker vortex A, in the meantime, tends to be crowded toward output passage 15 and directs less of the input fluid in a clockwise direction out through passage 15. Eventually, as illustrated in Figure 13, vortex B is positioned substantially at the center of chamber 13 while vortex A substantially blocks outlet passage 15. It is this condition during which the maximum outflow through, passage 16 occurs. As vortex A is forced closer and closer to outflow passage 15, two things occur: vortex A pinches off outflow through outflow passage 15 and it also moves substantially closer to the mouth of member 17. In this condition vortex A receives fluid flowing at a much higher velocity than the fluid received by vortex B. Therefore, as vortex A moves closer to output passage 15 it begins spinning faster, in fact much faster than vortex B. With output passage 15 blocked, vortex A begins moving back toward the center of chamber 13 and in so doing forces the slower spinning vortex B back away from the center. This tendency is increased by the fact that the jet itself is issued toward the center of the chamber 13 and, if left unaffected by other influences, would tend to flow toward that center. Now when the vortices approach the condition illustrated in Figure 11, vortex A is dominant and continues toward the center of the chamber 13. As was the case with vortex A when vortex B dominated, vortex B is eventually pushed to a position illustrated in Figure 15 whereby it blocks outflow through output passage 16. During this condition vortex A is centered in chamber 13 and substantially all of the outflow proceeds through output passage 15. Vortex B is now in a position to receive the high velocity fluid from the inflowing jet so that vortex B begins spinning faster and faster, taking on a growing position of dominance between the two vortices. Thus vortex B moves closer toward the center of chamber 13 as illustrated in Figure 14. More fluid begins to egress through output passage 16 and less through output passage 15 as vortex B moves closer toward the center, all the time pushing vortex A back away from the center of chamber 13. The. cycle is complete when the two vortices achieve the positions illustrated in Figure 11 once again with equal flow through output passages 15 and 16. The cycle then repeats in the manner described. Summarising the afore-described operation, initial flow of the jet into chamber 13 produces a straight flow across the chamber which splits into two loops near the far chamber wall. Each split-off and reversed loop flow tends to form a vortex which exerts a force on the jet. The resulting unstable balance between the two vortices on either side of the flow cannot sustain the momentary initial condition since any minute asymmetry, causing a corresponding increase in one of the reverse flow loops, causes a decrease in reverse flow and force on the opposite side of the jet. This in turn begins to deflect the jet toward the side with the weaker reverse flow loop, which further enhances the action of the phenomenon. In other words, a positive feedback effect is present and it causes the flow exiting from the chamber to veer toward one side of the chamber until a new balance of vortices is reached. It must be recognized that the occurring phenomena are inherently of a transient dynamic nature such that any flow conditions are of a quasi-steady state nature wherein none of the existing flow patterns represents a stable state; that is, the flow state in any location is dependent upon its prior history due to the fact that local flow states influence and are influenced by those flow states in other locations only after a delay in time. Even though the stronger of the two existing vortices might appear capable of sustaining the illustrated flow pattern at any point , the quasi-steady state effect of the outflow into one or more of the output channels causes the pattern in the chamber to become more symmetrical. This in turn causes a diminution of reverse flow and, simultaneously, causes an increase in the reverse flow on the opposite side. Both effects become effective after a respective time delay. This time delay is additionally increased due to the fact that the rotational energy in the motion of the two vortices must dissipate before flow reversal can be effected. Thus for a brief period of time outflow through one output passage remains essentially constant (although its velocity may increase as its flow area is constricted) before diminishing and consequently its influence on the adjacent counterflow is also sustained for a similar period of time. The flow pattern becomes more symmetrical and the buildup of the opposite reverse loop flow causes outflow to the opposite output channel. The vortex loop effects in large part comprise inertance and compliance phenomena with energy storage mechanisms, all of which are essential to the oscillation function.

The resulting output flow from the oscillator 10 is best illustrated in Figure 1 as alternating slugs of fluid issue from passages 15 and 16. It should be noted. that the cross section of chamber 13 illustrated in Figure 2 need not be rectangular but may be elliptical, in the form of a meniscus, or any other varying depth configuration. Similarly the plan form of chamber 13 need not be circular as shown but may be substantially any configuration such as the rectangular configuration illustrated in Figure 4. Specifically, element 20 in Figure 4 is shown with only the bottom plate 21, the top plate being removed for purposes of simplification and clarity of description. In fact, for most of the oscillators shown and described hereinbelow, the top plate has been removed for these purposes. Oscillator 20 includes an inlet opening 22 similar to inlet opening 18 of Figure 1 and a generally U-shaped member 23 similar to U-shaped member 17 in Figure 1. Outlet pass- ages 25 and 26 on either side of U-shaped member 23 correspond to outlet passages 15 and 16 of Figure 1. An oscillation chamher 24 is generally rectangular in configuration with its width corresponding to the distance between the extremities of passages 25 and 26. The output passages 25 and 26 are directed into an output chamber 27 which is a continuation of chamber 24 beyond U-shaped member 23 and has side wails which extend parallel all the way to outlet opening restriction 28. Oscillation of the jet issued from member 23 proceeds in the manner described in connection with Figures 11 through 15. The squared-off or rectangular shape of chamber 24 affects the shape of the output pulses but does not prevent oscillation from occurring. More specifically, the oscillation cycle in a chamber configured such as chamber 24 tends to have a greater dwell in the extreme positions where maximum flow through each output passage occurs. The resulting output slugs of fluid tend to have more discrete leading and trailing edges than the tapered leading and trailing edges shown in Figure 1.

Output chamber 27 receives the alternating slugs of fluid in opposing rotational senses; that is, the flow from passage 25 tends to create a clockwise flow in chamber 27 whereas the flow through passage 26 tends to create a counter-clockwise flow in chamber 27. The result is the establishment of an output vortex in chamber 27, which vortex is alternately spun first in a clockwise and then in a counter-clockwise direction in response to the alternating inflows. The manner in which output chamber 27 provides a cyclically sweeping spray pattern is best described in relation to the embodiment of Figure 5.

Referring specifically to Figure 5, an oscillator/output chamber configuration 30 includes an input opening 31 for pressurized fluid which is directed into a generally circular chamber 34 by means of a generally U-shaped channel 32. U-shaped channel 32 is part of an overall flow divider section 33. Downstream of the common inlet and outlet opening 39 of oscillation chamber 34, the sidewalls 40 and 41 of the unit diverge such that sidewall 40 along with flow divider 33 forms outlet passage 35 from the oscil- lator, whereas sidewall 41 along with flow divider 33 forms outlet passage 36. The sidewalls 40 and 41 begin to converge toward outlet opening 38 in output chamber 37. The downstream surface of flow divider 33 is concave so that a generally rounded output chamber 37 results. Passages 35 and 36 deliver fluid into output chamber 37 in opposite rotational senses. The manner in which the spray is issued from chamber 37 is diagrammatically illustrated in Figure 16. Referring to Figure 16, the input flows from passages 35 and 36 produce an output vortex which alternately rotates first in a clockwise direction and then in a counter-clockwise direction. At each point across outlet opening 38 there is a summation of flow velocity vectors which determines the overall shape of the issued spray pattern from this outlet opening. For ease in reference and simplification only two such points are illustrated in Figure 16, namely, the extremities 43 and 44 of outlet opening 38. For the following discussion it is assumed that the vortical flow in chamber 37 is counter-clockwise as indicated by the arrow therein. At point 43 there is a tangential velocity V_T directed tangentially to the output vortex at that point, and a radial velocity component V_R directed radially from the output vortex at that point. The summation of vectors V_T and V_R is a resultant flow velocity R emanating from point 43. Tangential velocity vector V_T results solely from the spin effect in the vortex and thereby results only from the dynamic pressure at point 43 produced by the output vortex. The radial velocity vector V_R results from the static pressure and net flow into chamber 37 from passages 35 and

36. A similar analogy is presented for vectors V'_T and V'_R at point 44 on the other side of outlet opening 38. These vectors sum to provide a further resulting vector R'. Vectors R and R' define the extremities of the fluid issued from outlet opening 38 at a particular instant of time. At that instant of time the outflow from outlet 38 is confined between the vectors R and R'. These vectors diverge producing a tendency for the outflow to diverge; however, surface tension effects act in opposition to the divergence tendency to try to reconsolidate the stream. In most practical applications, particularly for high velocities, the issued flow tends to break up into droplets before too much consolidation is effected. Nevertheless, there is some reconsolidation so that there is no continuation in the divergence tendency. Important is the fact that flow issued from outlet opening 38 at any instant of time spreads in the plane of the output vortex. It is this spreading flow that .is oscillated back and forth, as the output vortex in chamber 37 continuously changes velocity and direction. An overall spray pattern of this type is illustrated in Figure 10 wherein it is noted that the sheet 45 sweeps back and forth in an almost sinusoidal pattern and within a short distance, depending on the pressure, begins breaking up into ligaments and then droplets of fluid as the issued stream 45 viscously interacts with the surrounding air. This viscous interaction is the mechanism which causes a cyclically swept jet to break up into multiple droplets and form a spray pattern of a generally fan-shaped configuration. However, in the case of the swept spreading flow pattern issued from outlet opening 38, the flow itself tends to break up into droplets much more readily than an integral jet, at corresponding pressures. As a corallary, smaller droplet sizes can be achieved with the use of output chamber 37 than can normally be achieved with a conventional fluidic oscillator of a comparable size at the same operating pressure.

In summary of the operation of chamber 37, it may be looked upon as serving as a restriction (analogous to an electrical resistance) and inertance (analogous to an electrical inductance) filter circuit to smooth out incoming pulsating signals and to combine the result in a suitable single output stream which remains substantially constant in amplitude but sweeps from side to side regularly as the vortex changes direction and speed. The static pressure in chamber 37 produces a radial velocity vector V_R at each point of the outlet opening 38. The spin velocity of the vortex in chamber 37 produces a tangential velocity vector V_T. I have observed that the sweep angle a illustrated in Figure 10 varies directly with the tangential velocity vector 7 and inversely with the radial velocity vector V_R. When the spin velocity is exceedingly large and the static pressure is exceedingly small so that the tangential velocity vector V_T dominates, I have observed fan or sweep angles α as large as 180 degrees. On the other hand when the static pressure dominates over the spin velocity so that the radial velocity vector V_R is relatively large, a minimal or hardly noticeable sweep angle a is produced. Thus by increasing the width of outlet opening 38, and thereby decreasing the static pressure in chamber 37, I have been able to achieve a significant increase in the fan angle α. Likewise, by shaping the contour of walls 40, 41 proximate outlet 38, such as by narrowing the region therebetween, I have been able to considerably reduce the fan angle α. These and other effects are illustrated in association with other embodiments described hereinbelow. Refer now to Figures 6 and 7 of the accompanying drawings. There is illustrated another form of the oscillator of the present invention. Specifically, oscillator 50 includes a top plate 52 and a bottom plate 51. Recesses are defined in bottom plate 51 to form the oscillator, the recesses being covered by cover plate 52 to provide the necessary sealing. Oscillator 50 differs from oscillator 10 of Figure 1 in two respects: first, the shape of the oscillation chamber 53 is generally trapezoidal rather than circular; and second, input fluid is delivered from supply passages 54 and 55 defined through bottom and top plates 51 and 52, respectively. Passages 54 and 55 are angled to direct the incoming fluid into chamber 53 as a common supply jet which oscillates in the same manner described in relation to the oscillator in Figure 1. Passages 54 and 55 permit the U-shaped member 17 of Figure 1 to be eliminated so that no structure is present in the plane of the oscillator. The trapezoidal chamber 53 and the rectangular chamber 24 of Figure 4 are merely examples of the multitude of variations that can be utilized in the oscillator chamber configuration and still achieve the desired oscillation. For example, the oscillating chamber may be elliptical, irregularly shaped, polygonal, or whatever, so long as there is room for the alternating vortices to develop and move in the manner described in relation to Figures 11 through 15.

Referring to Figure 8 there is illustrated a fluidic oscillator 56 of a conventional type, well known in the prior art, having outlet passages 58 and 59 which deliver the alternating outflow from the oscillator to an output region 57 constructed in accordance with the present invention. Chamber 57 operates in the same way described above for chamber 37 irrespective of the nature of the oscillator which delivers the alternating slugs of fluid thereto. To further illustrate this point, there is illustrated in Figure 9 an output chamber 60 which is fed by a schematically represented source of alternating pulses which may be any such source such as an alternating shuttle valve, a fluidic amplifier, etc.

Referring now to Figure 17 of the accompanying drawings there is illustrated an output chamber 61 similar in all respects to output chamber 37 in Figure 16 but which instead of having a single outlet opening 38 has two such outlet openings 62 and 63. The vector analysis applied to the embodiment of Figure 16 applies equally as well to the diagrammatic embodiment of Figure 17 where similar vectors are illustrated. From chamber 61, however, there are two outflows which issue, each being swept at the same frequency. However, the two resulting outputs diverge from one. another at any instant of time by somewhat more than the angle subtended between the two vectors V_R and V'_R. This is because the tangential vectors V_T and V'_T subtend a greater angle than exists between the radial vectors, as is the case in Figure 16. As a consequence two synchronized (in frequency) sweeping sheets issue to form a composite waveshape of the type illustrated in Figure 18.

It is to be noted, by means of further explanation of the operation of output chambers 37 and 61, that the radial vector V_R increases somewhat in amplitude at the time when the spin reverses direction; V_R decreases to a minimum value when the spin has its extreme maximum amplitude. Therefore, a phase shift exists between the maxima of the pulsating input signals to chambers 37 and 61 and the spin velocity maximum in the output vortex. It should also be noted that depending upon the particular design of the chamber the pressure at the center of the output vortex may fluctuate from below atmospheric pressure to above atmospheric pressure.

Referring to Figure 18, an oscillator, of the general type illustrated in Figure 1, is modified by incorporating two upstanding members 66, 67 on opposite sides of the jet issued from U-shaped member 68. Members 66 and 67 are shown as cylinders (i.e. circular cross-section) but their cross sections can take substantially any shape. Importantly, they are spaced slightly downstream from the ends of member 68 so that respective gaps 69 and 70 are defined between member 68 and members 66 and 67. The presence of members 66 and 67 and the resulting gaps has the effect of sharpening or "squaring off" the pulses issued from oscillator 64 as compared to the tapered pulses shown in Figure 1. More specifically, in reference to the discussion above relating to Figures 11 - 15, the displaced vortex takes longer to build up when members 66 and 67 are present, partly because of the loss of energy in the input jet in traversing the region of gaps 69, 70. This loss of jet energy means that the energy feeding the displaced vortex is less so that vortex build up takes longer. However, when the displaced vortex does build : up sufficiently to dislodge the centered vortex, it has grown to the point where the transition is rapid. Hence, there is a relatively long dwell time in the extreme positions (i.e. Figures 13 and 15) and a rapid transition between these positions; this results in sharp-edged pulses or slugs. Output chamber 65 tends to filter these sharp edges somewhat in its action as an RL (i.e. - restriction and inertance) filter. This is shown in the spray output waveforms 71 and 72 issued from output openings 73 and 74, respectively, in chamber 65. In addition, if the passages 75 and 76 are lengthened, thereby adding inertance, additional filtering is achieved. As described above in relation Co Figure 17, I have observed that the waveforms 71 and 72 issued from the two outlets of chamber

65 are synchronized in frequency and phase but are spread spatially by an angle which is greater than the angular spacing between outlet openings 73 and 74. This is because the tangential velocity vectors V_T and V'_T are displaced from one another by an angle which is greater than the spacing between the radial velocity vectors V_R and V'_R.

Figures 19 and 20 illustrate the manner in which the shape of the output chamber affects the sweep waveshape. In Figure 19 a generally circular oscillation chamber receives a jet from U-shaped member 78 and oscillation ensues in the manner previously described. The alternating output pulses from the oscillator are conducted by passages 79 and 80 to output chamber 81 which is formed between converging sidewalls 82 and 83. The convergence of the sidewalls produces a relatively narrow output chamber 81. The single outlet opening 84 issues a sweeping spray pattern having the waveform diagrammatically represented as 85. It is noted that waveform 85 has a slower transition between sweep extremities (i.e. a longer dwell 86 in the center) than does sweep waveform 45 of Figure 10. Also noted is the fact that the sweep angle α is somewhat smaller than in waveform 45. These effects result from the narrowed output chamber 81, primarily because the radial velocity component V_R is larger when the output chamber is narrow. The larger radial velocity component is due to the fact that the static pressure in the narrowed chamber volume is greater, and V_R is affected by the static pressure. Waveform 85 results in a spray pattern having a heavier concentration of fluid droplets or particles in the center than at the extremes of the sweeping flow.

In contrast oscillator/output chamber combination 90 of Figure 20 produces a different waveform 91. Specifically, element 90 is in the general form of an oval which is wider at its outlet chamber end than at its oscillation chamber end. The oscillation chamber 92 receives a fluid jet from U-shaped member 94 and produces oscillation in much the same fashion described in relation to Figures 11 through 15. The common inlet and outlet opening for chamber 92, however, subtends more than 180º^, of the generally circular chamber 92. In other words, the sidewalls 95, 96 of the element 90 are straight diverging walls between the oscillation chamber 92 and output chamber 93. Member 94 is disposed between the sidewalls and forms therewith connecting passages 97, 98 between chambers 92 and 93. The radius of oscillation chamber 92 is substantially the same as in chamber 77 in Figure 19. However, output chamber 93 is considerably wider than chamber 81. The resulting waveform 91 is seen to be considerably different than waveform 85 of Figure 19. Specifically, waveform 91 is a generally triangular wave, with sawtooth tendencies, in which the central con¬centration 86 of Figure 19 is not present. This absence of central concentration results from the widening of chamber 93 as compared to chamber 81. The transition region (i.e. between the extremes) of the sweep waveform 91 is much smoother and it is also noted that it exhibits a concave (as viewed from downstream) tendency. The concavity indicates that the fluid in the center of the pattern is moving sligh ly more slowly than the fluid at the sweep extremities. In general, waveform 91 provides very even distribution across the sweep path. The oscillator/output chamber combination of the present invention has been found to provide the same pattern when scaled to different sizes. Thus, a small device for use as an oral irrigator may have a nozzle width at U-shaped member on the order of a few thousandths of an inch. This oscillator may be scaled upward in every dimension to provide, for example, a large decorative fountain and still produce the same, albeit larger, waveform. A scaled outline of an oscillator/output chamber combination 100, similar to the device in Figure 19, is illustrated in Figure 21. As can be seen, all dimensions are scaled to the width of the nozzle W formed at the outlet of the generally U-shaped member 101. The diameter of the oscillation chamber 102 is 8W. The distance between the nozzle and the far wall of chamber 102 is 9W. The common inlet and outlet opening for chamber 102 is 7W and is spaced 2W from the nozzle. The closest spacing between member 101 and the sidewalls 103, 104 is 2.5W, and the maximum spacing between the sidewalls is 11W. The length of the unit 100 is 25W and the width of outlet opening 105 from output chamber 106 is 2.5W. Device 100 can be constructed to substantially any scale and operates in accordance with the principle described herein. It is to be stressed, however, that the relative dimensions of device 100 are intended to achieve only one of multitudinous waveforms possible in accordance with the present invention and that these dimensions are not to be construed as limiting the scope of the invention.

Figures 22 through 26 illustrate comparative waveforms attained when various dimensions of the oscillator/output chamber are changed. Specifically, oscillator 110 of Figure 22 is shown with relatively short outlet passages 111, 112. The resulting issued pulses are shown with amplitude plotted against time. The output pulse trains consist of sawtooth waves which are 180° separated in phase. This may be compared to oscillator 113 with considerably longer outlet passages 114 and 115. Again sawtooth waveforms are produced, but the individual pulses are considerably smoothed and the frequency is considerably less. This is primarily due to the fact that the longer passages 114 and 115 introduce greater inertance (the analog of the electrical parameter inductance) in to the oscillator, making the response in the oscillation chamber considerably slower. In Figure 24 the oscillator 110 (of Figure 22) with short outlet passages 111 and 112 is combined with a relatively small volume output chamber

116. The waveform 117 of the sweeping spray issued from chamber 116 is a sawtooth waveform wherein the transition portions between sweep extremities bulges in a downstream direction. This signifies that the flow in the middle or transition portion of the sweep pattern is moving at a slightly greater velocity than at the extremes. This may be compared to waveform 91 of Figure 20 wherein the bulge is in the opposite direction, signifying slower travelling fluid in the central portion of the sweep pattern. The reason for this is that in the smaller output chamber 116 there is less vortical inertance so that spin velocity tends to slow down more quickly after the impetus of a driving pulse from the oscillator subsides. The slow down permits the radial velocity V to dominate and impart a high radial velocity to the issued fluid during the central part of the sweep. Oscillator 110 is illustrated again in Figure 25, this time in combination with a somewhat widened output chamber 119. Chamber 119 affords a greater vortical inertance, providing less of a tendency for the vortex to slow down when a driving pulse subsides. The result is a waveform 118 in which the downstream bulge is not present, primarily because the dominance of the radial velocity vector is no longer present. Increasing the output chamber size even further, as with chamber 120 of Figure 26, produces a waveform 121 wherein the central portion tends to bulge slightly in an upstream direction or opposite that in waveform 117 of Figure 24. This shows a tendency toward waveform 91 of Figure 20 wherein the fluid at the center of the pattern begins to flow more slowly than the fluid at the extremes. This results from an increased vortical inertance in the larger chamber 120, which inertance produces a tendency for the vortex to continue spinning after the driving pulse subsides and thereby causes the tangential velocity vector V_T to take on dominance. Further, the dominance of the tangential vector V_T causes the sweep angle to increase as seen from the larger angle subtended by waveform 121 than by waveforms 117 and 118. In all three embodiments (Figures 24, 25 and 26) distribution of fluid within the sweep pattern is relatively even.

Referring next to Figure 27, an oscillator 125 is constructed in a manner similar to oscillator 64 of Figure 18 in that members 126, 127 are spaced slightly from U-shaped member 128 to provide gaps 130, 131 which provide communication between the input jet and the output pulses. As described in relation to Figure 18, this construction tends to square off or sharpen the pulses, producing agreater dwell in the extreme portions of the oscillator cycle and a relatively fast switching or transition "between extremes. This is manifested by the amplitude versus time slots of the output pulses 124 and 123, which show a flattened peak as compared to the somewhat sharper pulse peaks illustrated in Figures 22 and 23. Oscillator 125 is illustrated again in combination with output chamber 132 in Figure 28. Outlet opening 133 from chamber 132 issues a spray pattern having the waveform 134 which has longer dwell times at the sweep extremities than the waveforms in Figures 24, 25 and 26. As described in relation to Figure 18, the members 126, 127 tend to delay the re-strengthening of the displaced vortex (A in Figure 13) so that there is greater dwell at the extremes of the oscillation cycle.

Referring to Figure 29, there is illustrated another oscillator/output chamber combination 135. The oscillator portion of device 135 is characterized by an oscillation chamber 136 which is considerably longer than those described above and which includes a far wall 137 which is convex rather than concave. In addition, oscillator output passages 138 and 139 are somewhat wider than those illustrated in the embodiment described above. The output chamber 140 of device 135 is characterized by an opening 142 in U-shaped member 141 which issues fluid directly into the output chamber. Lengthening the oscillator chamber has the effect of reducing the frequency of oscillation since the vortices A and B of Figures 11 - 15 must travel greater distances during the oscillation cycle. I have found that such lengthening, beyond a certain point, requires a widening of outlet passages 138 and 139 in order to maintain uniform oscillation. Beyond a certain point (e.g. when the length of chamber 136 exceeds the outlet width of member 141 by twenty-five times) if the output passages are not widened there is a backloading in chamber 136 which either produces sporadic oscillation or a stable condition. Longer oscillation chambers and their inherent lower frequencies are very suitable for massaging showers or decorative spray fountains and may be used with or without the convex wall 137 feature or the fillin jet nozzle feature 142.

Convex wall 137 has the effect of causing the oscillation cycle to pass much more quickly between extreme positions than does a flat or concave wall. With a faster transition, the rise and fall times of the pulses delivered to output passages 138 and 139 are shortened. This feature may be used independently of the lengthened oscillation chamber and the fill-in jet. The fill-in jet from opening 142 is used to increase the amount of fluid in the center of the issued spray pattern. In effect, this shortens the transition time between extreme sweep positions, causing greater "dwell" in the mid-portion of the sweep cycle than at the ends. This is reflected in the waveform 144 of the spray pattern issued from outlet 143 wherein it is noted that the transition region is bowed outward considerably. Relating this feature to the vector discussion and Figure 16, fill-in flow from nozzle 142 imparts additional magnitude to the radial vector V_R, both in a dynamic sense

(since the fill-in flow is directed along the radial vector direction) and as additional static pressure in output chamber 140.

The features described in relation to Figure 29 provide additional techniques for shaping the output spray pattern and may be used with any of the other oscillators and output chambers described herein. Oscillator 145 of Figure 30 is illustrative of an embodiment wherein multiple outlets variously directed are achieved. Specifically a nozzle structure 146 issues a fluid jet into oscillation chamber 147 which may take any configuration consistent with the operating principles described in relation to Figures 11 - 15. Outlet passages 148 and 149 are shown as being turned outwardly, substantially at right angles to the input j et, rather than being directed in 180° relation to that jet. It is to be understood that these passages can be turned at any angle or in any direction, in or out of the plane of the drawing, depending upon the application. Further, one or more of these passages, for example passage 149, may be bifurcated to provide two passages 150 and 151 which conduct co-phasal output pulses. It is to be understood that any of passages 148, 149, 150, 151 may be lengthened or shortened to delay the issuance of output pulses therefrom to obtain a variety of different effects and results.

The fan-shaped spray patterns described as being issued by the output chambers described above provide a line or one-dimensional pattern when they impinge upon a target. In other words, when the cyclically swept spray impacts against a surface interposed in the spray pattern, the fluid sweeps back and forth along a line on that surface. It is also possible to achieve a two-dimensional spray pattern from the output chamber of the present invention. An output chamber embodiment for achieving spray coverage of a two-dimensional target area is illustrated in Figures 31 and 32. Specifically, an output chamber 152 is fed alternating fluid pulses from passages 153 and 154. The outlet opening 155 from chamber 152, instead of merely being a slot defined in the natural periphery of the chamber, is in the form of a notch cut into the chamber. In the embodiment shown the notch is cut along the central longitudinal axis of the device by a circular blade to provide an arcuate notch 156 perpendicular to the plane of chamber 152 and having a V-shaped cross-section. Cutting the outlet into the chamber allows the static pressure therein to expand in all directions. As a consequence, the spray issued from the outlet 155 follows the contours of notch 156 to provide a sheet of fluid in the plane of the notch (i.e. perpendicular to the plane of the chamber 152). This sheet is swept back and forth due to the alternating vortex action described in relation to Figure 16 so that the spray pattern issued from outlet 155 forms a cyclically sweeping sheet. This sweeping sheet covers a rectangular area when it impinges on a target disposed in the spray path, thereby affording two-dimensional spray coverage. I have found that as the notch is cut deeper into chamber 152, the angle of the sheet expansion in the vertical plane increases. Various contouring of the notch cross-section permits contouring of the distribution of droplets in the vertical plane (i.e. perpendicular to the chamber).

Another output chamber embodiment is illustrated in Figures 33 and 34; In this embodiment the output chamber 160 receives alternating fluid pulses from passages 161 and 162 and delivers a planar or fan shaped swept pattern from a slot shaped outlet opening 163. However, outlet opening 163 is formed in the floor (or ceiling) of the chamber rather than being defined in the end wall thereof. The same vectorial analysis applied to the chamber of Figure 16 is applicable to chamber 160 but in chamber 160 it is noted that outlet opening 163 extends along the radius of the alternating vortex. Since the spin velocity of a vortex varies at different radial points, the tangential velocity vector V varies along the length of opening 163. The result renders the issued spray pattern waveform somewhat assymmetric into the plane of the drawing in Figure 34, the asymmetry being greater for longer outlet openings.

Still another output chamber configuration is illustrated in Figures 35 and 36. This embodiment, like that of Figures 31 and 32, provides a swept sheet pattern which covers a two-dimensional target area rather than a lineal target. The output chamber 165 receives alternating fluid pulses from passages 166 and 167, similar to chambers described above. However, chamber 165 is expanded cylindrically, perpendicular to the plane of passages 166, 167, so that the depth of chamber 165, as best seen in Figure 36, is substantially greater than that of previously described chambers. Outlet slot 168 is defined in the periphery of the chamber and extends parallel to the cylindrical axis of the chamber. When pressurized fluid is issued from chamber 165 it is formed into a sheet 169 by slot 168, the sheet residing in a plane perpendicular to the plane of vortex spin in chamber 165. The alternating spin causes the issued sheet to oscillate back and forth according to the principles described in relation to Figure 16. The resulting waveform provides an even distribution of droplets along the sheet height. Distribution along the sheet width (the dimension shown in Figure 35) is determined by the various features and factors described herein relating to oscillator and output chamber configurations .

The oscillator/output chamber configuration 170 in Figure 37 is characterized by its asymmetry with respect to its longitudinal centerline. Oscillator chamber 170 receives a jet from nozzle 171 of member 172 in a direction which is not radial but nevertheless acros the chamber. As a consequence, the oscillation, which ensues according to the principles described in relation to Figures 11-15, is unbalanced in that the fluid slugs issued into outlet passage 175 are of longer duration than the pulses issued into outlet passage 176. As a consequence, the clockwise spin in output chamber 173 has a longer duration than the counter-clockwise spin and the spray pattern issued from outlet opening 174 is heavier on the bottom side (as viewed in Figure 37) of the longitudinal centerline than the top side. Asymmetrical construction of the oscillator, output chamber, positioning of member 172, location of outlet 174, etc., may all be utilized to achieve desired spray patterns.

The output chamber 177 of Figures 38 and 39 has two characterizing features. First, the outlet opening 185 is a generally circular hole 185 defined through the ceiling or floor of the chamber, substantially at the chamber center. Second, flow dividers 178 and

179 are positioned to divide the incoming fluid pulses. Specifically, divider 178 divides an incoming pulse between passages 183 which extends around the chamber periphery and passage 184 which is disposed on the radially inward side of divider 178. Likewise, divider 179 divides an incoming pulse of the opposite sense between outer passage

180 and inner passage 181. The outlet opening 185, positioned as described, provides a hollow conical spray pattern 186 which alternately rotates in one direction and then the other as the output vortex in chamber 177 alternates spin directions. The spread angle of the conical pattern 186 varies with spin velocity so that as the output vortex speeds up and slows, down during direction changes, the spray pattern 186 alternately opens (186) and closes (187). In this manner the pattern 186, when impinging upon a target, covers a generally circular area. The flow dividers 178 and 179 impart spin components to the output vortex at four locations instead of two, resulting in "minimal movement of the output vortex in the chamber. The output vortex is thus maintained centered over outlet opening 185 to assure the symmetry of the spray conical pattern 186, 187. The features of Figures 38, 39 (namely, location of outlet 185 and presence of dividers 178, 179) can be used independently.

A similar spray pattern is achieved with the outlet chamber 190 of Figures 40, 41. Specifically, output chamber 190 is in the form of a cylinder which extends out of the plane of the incoming pulses from passages 192, 193 and then tapers in a funnel-like fashion, towards a central outlet opening 191. Again the resulting output spray pattern is a spinning conical sheet which continuously changes spin direction as the output vortex direction changes in chamber 190 and which goes from an expanded wide-angle cone 194 at maximum spin to a relatively contracted cone 195 at minimum spin. The device of Figures 38, 39, and that of Figures 40, 41 is useful for decorative fountains, showers, container spray nozzles, etc.

The apparatus of Figures 42 and 43 expands the principles of the outlet chamber of the present invention to three dimensional spin in the output vortex. Specifically, a generally spherical chamber receives a pair of alternating fluid signals or pulses from a first oscillator or other source 201 at diametrically opposed inlet openings 202 and 203. Another pair of diametrically opposed inlet ports 204, 205 receive alternating fluid signals or pulses from a source 206. The signals from source 201 have a frequency f₁; the signals from source 206 have a frequency f₂. The plane of ports 202 , 203 is perpendicular to the plane of ports 204, 205, although this is by no means a lioiting feature of the present invention. The outlet opening 207 for the spherical chamber 200 is located where the intersection of. these two planes intersects the chamber periphery. Depending upon the relative frequency and phase of the signals from sources 201 and 206, a variety of output spray patterns can be obtained. Thus, if frequencies F₁ and f₂ are equal but are displaced in phase by 90°, a hollow spray pattern is issued which is of square crosssection if the input signals are well-defined pulses, of circular cross-section if the input signals are sinusoidal functions, etc. If frequency f₁ is twice that of f₂, and the input signals are sinusoidal, a figure eight pattern is generated. In other words, the cross-section of the pattern issued from outlet opening 207 takes the form of the well-known Lissajous patterns achieved on cathode ray oscilloscope displays. By choosing proper phase and frequency relationships between the input signals, an extremely large variety of waveshapes may be achieved. Referring to Figures 44, 45 and 46 there are three oscillator/output chamber combinations illustrated. In the three devices 210, 211 and 212, respectively, the sizes and shapes of the oscillator chamber' 213 and output chamber 214 are substantially the same. The differences reside in the sizes of the common inlet and outlet openings 215 of all three devices, the opening being smallest in device 210 , largest in device 212. The waveforms of the spray patterns are affected as follows: For the smallest opening (device 210) the observed waveform was a well-defined sawtooth with slight rounding at the extremities. For the medium opening (device 211) the sawtooth waveform showed less rounding or curvature at the extremities as compared to that for device 210, For the largest opening 215 (deyice 212) even less rounding was observed, the waveform appearing almost triangular, substantially like waveform 91 of Figure 20, The last mentioned waveform provides the most even droplet distribution of the three. In general it may be stated that the wider the opening 215, the less the flow restriction at the oscillator output anil the greater the filtering effect in the output chamber.

In Figure 47 an oscillator/output chamber combination 216 includes an oscillation chamber 217 and an output chamber 218. This device is characterized by the fact that the side walls 220 and 221 converge just behind U-shaped jet-issuing member 219 to form a throat 223, and then diverge in the output chamber 218 and converge again to form an output opening 222. This configuration effects a flow reversal so that fluid which flows along sidewall 220 out of oscillation chamber 217 is turned at throat 223 to flow along the opposite wall as it enters the output chamber 218. Operation is the same as previously described for the non-reversing flow arrangement except that a greater spin effect is provided in chamber 218 by the wall curvature. In Figures 48 and 49 there is illustrated an embodiment of the oscillator of the present invention which is employed as a flow meter. Specifically a flow channel 225 is illustrated as a cylindrical pipe. It is to be understood that the channel 225 can take any configuration, and may even be open along its top. Fluid flow in the flow channel 225 is represented by the arrows shown in Figure 48. Two semi-oval members 226 and 227 are disposed with their major axes parallel to the flow direction and are slightly spaced apart to define a downstream tapering nozzle 229 therebetween. The downstream ends of members 226 and 227 are formed as downstream-facing cusps 230 and 231, respectively. A body member 228 has an oscillation chamber 232 defined therein, chamber 232 being shown as U-shaped in Figure 48 but capable of assuming any configuration consistent with the operational characteristics described herein for oscillator chambers. The oscillation chamber 232 is shown disposed symmetrically with respect to nozzle 229, but this is not a requirement. A pair of tiny pressure ports 233 and 234 are defined in the downstream end of chamber 232; again, these ports are shown disposed symmetrically with respect to nozzle 229 but this is not a limiting feature of the invention. The pressure ports 233 and 234 communicate with tubes 235, 236 which extend out through channel 225. In operation a portion of the flow in channel 225 is directed into nozzle 229 which issues a jet into chamber 232. Oscillation ensues in chamber 232 in the manner described in relation to Figures 11 - 15. Alternating outflow pulses are first directed upstream when egressing from chamber 232 and are then redirected by cusps 230, 231 into the main channel flow. As the jet in chamber 232 is swept back and forth, by the alternating vortices, the differentia pressure at ports 233, 234 (and therefore at tubes 235, 236) varies at the frequency of oscillation. I have found that the frequency of oscillation for the oscillator of the present invention varies linearly with the flow therethrough. Consequently, by employing a conventional transducer, for example an electrical pressure transducer, it is possible to provide a measurement of flow through channel 225. The flow metering arrangement of Figures 48, 49 is highly advantageous as compared to prior art attempts to employ fluid oscil lations as a flow measurement parameter. For example, only a small oscillator need be used, thereby minimizing any losses introduced by the oscillator. Further, the channel flow which by-passes the oscil lator (i.e. flow around the outside of members 226 and 227) serves to aspirate flow from the cusp regions 230, 231, thereby providing a differential pressure effect across the oscillator. Importantly, th negative aspiration pressure permits the by-pass flow to affect oscillator frequency and thereby permit more than just the limited flow through the nozzle 229 to be part of the measurement. Since flow velocity tends to vary somewhat across a channel, this use of a greater portion of the flow, without increasing losses, is highly advantageous. It is to be understood that all of the flow can be directed through the oscillator, if desired, but that losses are minimized if only a small part of the flow is so directed.

The oscillation frequency can be sensed in many places. pressure ports 233, 234 are particularly suitable because the dynamic pressure in the jet is available where these ports are shown, and that pressure is easily sensed. It is also possible to insert a hot wire anemometer or other flow transducing device 237 in one of the output passages of the oscillator to sense flow frequency. An in-line flow sensor embodiment is illustrated in

Figure 50. Specifically, all of the flow through a pipe 330 or other flow channel is directed into oscillation chamber 331. Flow chamber 331 is in the form of a generally U-shaped recess in body member 332. The open end of U-shaped chamber 331 is wider than tube 330 so that outflow can proceed from the chamber on either side of the incoming flow. Oscillation ensues in chamber 331, in the manner described in relation to chamber 232 of Figure 48, and alternating fluid pulses are directed out of the chamber at opposite sides of the incoming flow. The alternating pulses are received by outflow passages 333, 334, respectively, which turn 180° to redirect the oscillator outflow in the same general direction as the inflow in tube 330. Part of each of passages 333 and 334 is defined by body member 332 which has sides that converge to an apex 335 at the downstream end of the body member. As a consequence, passages 333 and 334 converge at apex 335 so that the fluid in each of these passages is joined in a common outflow channel 336. Frequency sensing and the required frequency to flow rate conversion can be accomplished by any of the numerous prior art techniques.

Still another embodiment of the present invention is illustrated in Figures 51 and 52. The flow sensor is made up of a top plate 340 and bottom plate 341 which may be of plastic, metal or any other material appropriate for the fluid environment. The oscillator is formed as recesses in the top surface of bottom plate 341 and is sealed by the top plate 340, the plates being secured to one another by adhesive material, screws, or any appropriate means. An inflowpassage 343 for metered fluid is formed in a projection 344 extending down from bottom plate 341. A suitable fitting 345 is employed to permit .inlet flow tubes to be readily connected to passage 343. Inlet passage 343 terminates at an inlet region 346 defined between the arms of a generally U-shaped member 347. U-shaped member, in point of fact, is a non-recessed portion of bottom plate 341 disposed in islandlike position within a generally oval-shaped recess or chamber 348. Flow from inlet region 346 is directed to impinge against end walls 349 at one end of chamber 348 whereupon oscillation o£ the flow ensues in the manner described above in relation to chamber 232 of 'Figure 48. Outflow from the oscillation is in the form of alternate fluid pulses directed on opposite sides of the inflow and received by passages 350 351. These passages are defined between member 347 and opposite side walls of chamber 348 and converge toward a downstream apex of body 347. The combined outflows are directed into outflow passage 352 which is provided with a suitable fitting 353 to permit connection to an outflow tube. The flow sensor of Figures 51 and 52 can therefore be inserted into a flow path by simply inserting in the path with connections to inlet fitting 345 and outlet fitting 353. Although the frequency in the apparatus of Figures 51 and 52 can be sensed by any conventional technique, a particularly useful technique is illustrated in those Figures. Specifically, a small, lightweight vane 354 is secured at one end to the downstream apex of body member 347 in such a manner that the vane extends downstream towards outflow passage 352. The vane is thus at the point of confluence of the alternating outflows in passages 350 and 351 and will tend to deflect as each alternate fluid pulse passes into passage 352 The frequency of deflection is the same as the frequency of oscillation and therefore is also proportioned to the flow through the flow sensor. A bore 355 is defined through upper plate 340 in alignment with the undeflected position of vane 354. Bore 355 is therefore in a position to serve as an optical path for sensing deflections in vane 354. A transducer 356 is disposed atop plate 340 for this purpose and serves to illuminate the vane 354 and sense reflections thereof as the vane passes back and forth in the chamber. By well known techniques these passes can be counted against a time base in transducer 356 of some other processing circuit and the result can be converted to a measure of flow. It should be noted that, since the vane passes bore 355 twice during each cycle of oscillation , the counted frequency is actually twice that of the actual oscillator frequency. This pro vides greater flow measurement resolution since half cycles of actual oscillator frequency correspond to a simple count. It would also be possible to have the vane 354 self-illuminated, whereby transducer 356 would contain no illumination source. In addition, the vane may be sensed at two or more locations in the sweep path, rather than at the center, to further enhance resolution.

Other types of conventional frequency sensing approaches may likewise be employed. For example, these include hot wire anemometers or thermistors positioned to sense the frequency of flow changes. A magnetic vane, similar to vane 354, could be sensed magnetically. Conductive fluid might be used and the frequency sensed electromagnetically. In addition, sensing may be done by means of Hall effect, capacitive sensing, ultrasonic sensing, strain gauge sensing, electroconductive surface contacts in open channel flows, etc. Although flow sensing is described hereinabove in terms of liquid flow, it is to be understood that the principles of the present invention are equally applicable to gaseous flow sensing.

It should be noted that although plates 340, 341 are referred to as "top" and "bottom", respectively, these terms are for ease in reference only and in actual use the device, can have any orientation. The oscillator and output chamber of the present invention have been described as having certain advantages. Included among these is the fact that the oscillator oscillates without a cover plate (i.e. without plate 12 of Figure 1) at low pressures. This is highly advantageous for many applications, including flow measurement in open channels or rivers.

The oscillator also operates with substantially all fluids in a variety of fluid embodiments, such as with gas or liquid in a gaseous environment, gas or liquid in a liquid environment, fluidized suspended solids in a gas or liquid environment, etc. Importantly, oscillation begins at extremely low applied fluid pressures, on the order of tenths of a psi, for many applications. Moreover, oscillation begins immediately; that is, there is no non-oscillating "warmup" period because there can be no outflow until oscillation ensues. The oscillator and output chamber can be symmetric or not, can have a variable depth, can be configures in a multitude of shapes, all of which can be employed by the designer to achieve the desired spray pattern.

The output chamber although shown herein to have smooth curved peripheries, can have any configuration in which a vortex will form. Thus, sharp corners in the output chamber periphery, while affecting the waveshape, will still permit operation to ensue as described in relation to Figure 16. Further, the number of outlets fro the output chamber, while affecting the waveshape, does not preclude vortex formation. Specifically, I have found that as the total outle area is increased the sweep angle α increases.. In particular, in a chamber similar to chamber 61 of Figure 17, I have found that by blocking off one of the outlet openings, the spray pattern issued from the other outlet opening reduced considerably, with the shape of the wave remaining about the same. Likewise, in chamber 37 of Figure 16, if the single outlet 38 is reduced in size, the angle of the sweep is reduced. These sweep angle changes are produced because the static pressure in the chamber is increased when the outlet is reduced and therefore the radial vector V_R begins to dominate. While I have described and illustrated various specific embodiments of my invention, it will be clear that variations of 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.

Claims

I CLAIM: A fluid oscillator comprising: nozzle means for forming and issuing a jet of fluid in response to application thereto of fluid under pressure; an oscillation chamber having a common inlet and outlet opening, said oscillation chamber being positioned to receive said jet of fluid from said nozzle means through said common opening, said oscillation chamber including: oscillation means for cyclically oscillating said jet back and forth across said chamber in a direction substantially transverse to the direction of flow in said jet; and flow directing means for directing fluid from the cyclically oscillated jet out of said chamber through said common inlet and outlet opening.

2. The oscillator according to claim 1 wherein said oscillation means comprises impingement means, disposed in said oscillation chamber in the path of said jet, for forming, on each side of said jet, vortices of said jet fluid which alternate in both strength and chamber position in phase opposition.

3. The oscillator according to claim 2 wherein said impingement means comprises a far wall of said chamber remote from said common inlet and outlet opening.

4. The oscillator according to claim 3 wherein said flow directing means comprises said far wall and opposing sidewalls of said chamber.

5. The oscillator according to claim 4 wherein said nozzle means is positioned to issue said jet generally radially across said oscillation chamber toward said far wall, and wherein said common inlet and outlet opening is defined as a space between said opposed sidewalls.

6. The oscillator according to claim - further comprising: a first outlet passage positioned at one side of said nozzle means to receive fluid flowing out of said common inlet and outlet opening along said one side of said jet; and a second outlet passage positioned at the opposite side of said nozzle means to receive fluid flowing out of said common inlet and outlet opening along said opposite side of said jet.

7. The oscillator according to claim 6 wherein at least one of said outlet passages is bifurcated.

8. The oscillator according to claim 6 further comprising: an output chamber; means connecting said first outlet passage to said output chamber for delivering fluid from said first outlet passage into said output chamber in a first vortical flow direction; means connecting said second outlet passage to said output chamber for delivering fluid from said second outlet passage into said output chamber in a second vortical flow direction; whereby in said output chamber an output vortex is established which alternately spins in one direction in response to inflow from said first outlet passage and in the opposite direction in response to inflow from said second outlet passage; and outlet opening means defined in said output chamber and communicating with ambient environment for issuing from said output chamber a cyclically sweeping flow pattern.

9. The oscillator according to claim 8 wherein said output chamber is formed between a pair of converging walls which terminate in spaced relation to define said outlet opening means.

10. The oscillator according to claim 8 wherein said outlet opening means includes a plurality of individual openings from said output chamber.

11. The oscillator according to claim 8 wherein said output chamber is defined in part by a ceiling, a floor and a continuous wall extending between said outlet passages and wherein said outlet opening means comprises at least one opening defined in one of said ceiling and floor.

12. The oscillator according to claim 8 wherein said nozzle means comprises a member disposed between said oscillation chamber and said output chamber, said member including a nozzle for issuing said jet at its upstream end and a further wall constituting part of said output chamber periphery at its downstream end.

13. The oscillator according to claim 12 wherein said further wall is concave.

14. The oscillator according to claim 12 wherein said further wall is substantially straight.

15. The oscillator according to claim 12 wherein said further wall is convex.

16. The oscillator according to claim 12 further comprising additional nozzle means in said member for issuing said applied fluid under pressure directly into said output chamber.

17. The oscillator according to claim 12 wherein said output chamber is substantially rectangular.

18. The oscillator according to claim 12 wherein said oscillation chamber includes first and second sidewalls which extend from said far wall in said oscillation chamber to beyond said member to constitute first and second sidewalls, respectively, of said output chamber.

19. The oscillator according to. claim 18 wherein said first and second outlet passages are defined between said member and the portions of said first and second sidewalls, respectively, which extend between said oscillation and output chambers.

20. The oscillator according to claim 19 wherein said first and second sidewalls converge throughout the length of said output chamber towards said outlet opening means.

21. The oscillator according to claim 19 wherein said first and second sidewalls in said output chamber first diverge and then converge in a downstream direction.

22. The oscillator according to claim 19 wherein said first and second sidewalls are substantially parallel throughout the length of said output chamber.

23. The oscillator according to claim 19 wherein said first and second sidewalls in said output chamber converge toward the downstream end of said chamber, and wherein said outlet opening means comprises at least one outlet opening defined between the converging first and second sidewalls.

24. The oscillator according to claim 23 wherein said output chamber is further enclosed between top and bottom walls extending generally perpendicular to said first and second sidewalls.

25. The oscillator according to claim 24 wherein the depth dimension of said output chamber between said top and bottom walls is greater than the depth of said first and second outlet passages.

26. The oscillator according to claim 25 wherein said outlet opening means comprises a slot defined through periphery of said output chamber, said slot being longer in its dimension parallel to the depth of said output chamber than in its width dimension extending between said first and second sidewalls.

27. The oscillator according to claim 25 wherein said outlet opening means comprises an outlet opening defined in at least one of said ceiling and floor.

28. The oscillator according to claim 27 wherein said outlet opening is defined substantially centrally in said output chamber.

29. The oscillator according to claim 28 wherein said output chamber tapers in its depth dimension toward outlet opening.

30. The oscillator according to claim 27 wherein said outlet opening is a slot disposed off-center in said output chamber.

31. The oscillator according to claim 24 wherein said outlet opening means includes a notch cut into the output chamber entirely through said top and bottom walls.

32. The oscillator according to claim 19 wherein said first and second sidewalls in said output chamber first diverge and then converge toward said outlet opening means, and wherein said first and second sidewalls slightly upstream of said output chamber converge to define an entry throat to said output chamber.

33. The oscillator according to claim 8 further comprising means for expanding the fluid flow pattern issuing from said outlet opening means in a direction normal to the sweep direction in said cyclically sweeping flow pattern.

34. The oscillator according to claim 8 further comprising means in said output chamber for issuing said cyclically sweeping flow pattern in a generally fan-shaped spray subsisting substantially in a common plane with said output vortex.

35. The oscillator according to claim 8 further comprising means for issuing said cyclically sweeping flow pattern as a cyclically swept fluid sheet extending significantly out of the plane of the output vortex.

36. The oscillator according to claim 5 wherein said oscillation chamber is generally circular, said common inlet and outlet opening subtending an arc on the oscillation chamber periphery.

37. The oscillator according to claim 36 wherein said arc is greater than 184°.

38. The oscillator according to claim 36 wherein said arc is less than 180°.

39. The oscillator according to claim 36 wherein said arc is substantially equal to 180°.

40. The oscillator according to claim 5 wherein said oscillator chamber is generally rectangular.

41, The oscillator according to claim 5 wherein said far wall in said oscillation chamber is substantially flat.

42. The oscillator according to claim 41 wherein the sidewalls of said oscillation chamber diverge from said far wall toward said common inlet and outlet opening.

43. The oscillator according to claim 5 wherein said far wall is concave.

44. The oscillator according to claim 5 wherein said far wall is convex.

45. The oscillator according to claim 5 further comprising first and second members disposed proximate said common inlet and outlet opening and spaced from said nozzle means, each member being disposed on a negative side of the jet issued from said nozzle means.

46. The oscillator according to claim 6 disposed in a flowing fluid to measure the flow thereof, said flowing fluid corresponding to the fluid under pressure applied to said nozzle means, said oscillator further comprising sensing means for monitoring cyclic variations of a flow parameter in said chamber.

47. The oscillator according to claim 46 wherein said sensing means comprises a pair of pressure ports defined in said far wall, said pressure ports being symmetrically positioned with respect to said nozzle means.

48. The oscillator according to claim 46 wherein said sensing means comprises means for measuring cyclic flow variation in at least one of said outlet passages.

49. The oscillator according to claim 46 wherein said first and second outlet, passages are curved to issue fluid in the same flow direction as said flowing fluid.

50. The oscillator according to claim 46 wherein said nozzle means has an inlet end which is streamlined and positioned to face directly upstream in said flowing fluid, and wherein said outlet passages are positioned to be aspirated by said flowing fluid.

51. A spray-forming ice comprising: means for providing first and second fluid flows of varying amplitudes and different phases; a chamber having peripheral walls; means for directing said first and second fluid signals in opposite generally tangential directions into said chamber along said

57 . The device according to claim 56 wherein said opening is a slot having a length perpendicular to the plane of said output vortex which is greater than its width in the plane of said output vortex.

58. The device according to claim 56 wherein said opening is a slot having a length in the plane of said output vortex which is greater than its width perpendicular to the plane of said output vortex.

59. The device according to claim 55 wherein said outlet means comprises a plurality of openings in said sidewalls.

60. The device according to claim 55 wherein said outlet means comprises an opening in one of said top and bottom walls.

61. The device according to claim 60 wherein said opening is disposed substantially centrally in said chamber.

62. The device according to claim 60 wherein said opening is a slot extending radially in one of said top and bottom walls.

63. The device according to claim 55 wherein said outlet means comprises a notch defined through said top and bottom wall and said sidewalls.

64. The device according to claim 55 wherein said outlet means comprises means for issuing said output flow in the form of a cyclically swept sheet of fluid - extending in width perpendicular to the plane of said output vortex.

65. The device according to claim 51 wherein said outlet means comprises means for forming said output flow into a sheet of fluid expanding normal to the direction in which said output flow is cyclically swept.

66. The device according to claim 51 wherein said chamber is defined between first and second sidewalls which converge toward said outlet means.

67. The device according to claim 51 further comprising first and second flow dividers positioned in the paths of said first and second pulse trains, respectively, to divide the fluid pulses into two separate paths, said flow dividers each having curved sidewalls shaped to direct the divided pulse flows rotatiαnally in said chamber.

68. The device according to claim 51 wherein said chamber is semi-spherical.

69. The device according to claim 68 wherein said means for directing first and second pulse trains comprises first and second substantially co-planar flow passages arranged to issue said first and second pulse trains in opposite tangential directions into said chamber, and wherein said outlet means include an opening from said chamber to ambient residing in the plane of said first and second flow passages.

70. The device according to claim 69 further comprising third and fourth co-planar flow passages residing in a second plane other than that of said first and second flow passages and including said opening therein and arranged to issue respective third and fourth fluid pulse trains in opposite tangential directions into said chamber.

71. The device according to claim 70 wherein said second plane is perpendicular to the plane of said first and second flow passages.

72. The device according to claim 71 wherein said first and second pulse trains are.equal in frequency and displaced in phase by 180° and said third and fourth pulse trains are equal in frequency and displaced in phase by 180°.

73. The device according to claim 72 wherein the frequencies of said first and third pulse trains are equal but displaced in phase by 90°.

74. The device according to claim 72 wherein the frequencies of said first and second pulse trains are twice the frequency of said third and fourth, pulse trains.

75. The method of providing an oscillating fluid flow comprising the steps of: impinging a fluid jet against a wall; and dividing the impinging jet into two oppositely recirculating vortical flow patterns, one on each side of said jet, which increase and decrease in size in phase opposition.

76. The method of claim 75 wherein the step of Impinging includes the step of issuing said fluid jet into a chamber through a common opening to impinge upon a wall of said chamber; and further comprising the step of alternately flowing fluid from said two vortical flow patterns out of said chamber through said common opening.

77. A method of spraying fluid comprising the steps of: alternately spinning a body of pressurized fluid in opposite directions in a chamber; and issuing fluid from said chamber in a direction which varies with the spin velocity of the fluid therein.

78. The met according to claim 77 wherein the step of issuing includes issuing the fluid from said chamber in the plane of the spinning liquid in a direction determined by the resultant vector of the spin velocity and the static pressure in said chamber.

79. A device for spraying liquid comprising: a body member; an inlet for receiving pressurized liquid into said body member; first and second outlet openings for issuing pressurized liquid from said body member in predetermined general directions into ambient environment; and sweeping means inside said body member for sweeping the liquid issued from said outlet openings back and forth transversely of said predetermined general directions to provide two simultaneous swept spray patterns.

80. The device according to claim 79 wherein said means comprises: means for providing first and second repetitive fluid signals of varying amplitudes and different phases; a chamber; means for directing said first and second fluid signals into said chamber in opposite generally tangential directions; and means forming a vortex in said chamber from the fluid supplied from said first and second fluid signals, said vortex alternately spinning clockwise and counter-clockwise in response to said first and second fluid signals, respectively; wherein said first and second outlet openings are located at the periphery of said chamber and at the outer edge of said vortex and issues pressurized liquid from said vortex In a direction determined by the rotational speed and direction of said vortex,

81. A spray device comprising: a body member having a chamber region therein, an inlet open ing for conducting pressurized liquid into said chamber region, and at least first and second outlet openings for issuing pressurized liquid from said chamber region to ambient environment; fluid oscillator means in said chamber region for providing alternating oppositely-directed fluid vortices in response to conduction of said pressurized liquid into said chamber region; and means responsive to said, alternating fluid vortices for causing fluid to issue in cyclically swept flow patterns from each of said first and second outlet openings.

82. The method of oscillating a fluid jet comprising the steps of: issuing said jet into a chamber having a common inlet and outlet opening; forming alternating oppositely-directed fluid vortices in said chamber from the fluid in said jet; under the influence of said alternating vortices, alternately directing fluid to opposite sides of said jet and out of said chamber through said common inlet and outlet opening.

83. The method according to claim 82 wherein the step of forming comprises the steps of: impinging the issued jet against a peripheral wall of said chamber; and alternately directing fluid from the impinging jet in opposite tangential directions along said peripheral wall.

84. A flow sensor for measuring fluid flow comprising: means for issuing a defined stream made up of at least part of said fluid flow; an oscillation chamber having a common inlet and outlet opening, said oscillation chamber being positioned to receive .said defined stream through said common opening, said oscillation chamber including: oscillation means for cyclically oscillating said stream back and forth across said chamber in a direction substantially transverse to the direction of flow in said jet; flow directing means for directing fluid from the cyclically oscillated stream out of said chamber through said common inlet and outlet opening; and sensing means for sensing the cyclic variation of the oscillating stream.

85. The flow sensor according to claim 84 wherein said osdilation means comprises impingement means, disposed in said oscillation chamber in the path of said jet, for forming, on each side of said jet, vortices of said jet fluid which alternate in both strength and chamber position In phase opposition.

86. The flow sensor according to claim 85 wherein said impingement means comprises a far wall of said chamber remote from said common inlet and outlet opening, and wherein said flow directing means comprises said far wall and opposing sidewalls of said chamber.

87. The flow sensor according to claim 86 wherein said mean for issuing is positioned to issue said stream generally radially across said oscillation chamber toward said far wall, and wherein said common inlet and outlet opening is defined as a space between said opposing sidewalls.

88. The flow sensor according to claim 84 further comprising: a first outlet passage positioned at one side of said defined stream to receive fluid flowing out of said common inlet and outlet opening along said one side; and a second outlet passage positioned at the opposite side of said defined stream to receive fluid flowing out of said common inlet and outlet opening along said opposite side.

89. The flow sensor according to claim 88 wherein said first and second outlet passages converge to form a common outlet passage.

90. The flow sensor according to claim 88 wherein said sensing means comprises a pair of pressure ports defined in said chamber, said pressure ports being symmetrically positioned with respect to said defined stream when undeflected.

91. The flow sensor according to claim 88 wherein said sensins means comprises means for measuring cyclic flow variation in at least one of said outlet passages.

92. The oscillator according to claim 88 wherein said first and second outlet passages are directed to issue received fluid in the same flow direction as said fluid flow.

93. The oscillator according to claim 92 wherein said means for issuing has an inlet end which is streamlined and positioned to face directly upstream in said fluid flow, and wherein said outlet passages are positioned to be aspirated by said fluid flow.

94. The flow sensor according to claim 89 wherein said sensing means comprises: vibratable means positioned in said flow sensor to vibrate at the frequency of oscillation of said stream; detector means for counting vibration of said vibratable means.

95. The flow sensor according to claim 94 wherein said detector means includes: means for illuminating said vibratable means; and means for optically sensing vibration of said illuminated vibratable means.