US3554206A

US3554206A - Comparator amplifier

Info

Publication number: US3554206A
Application number: US714683A
Authority: US
Inventors: Peter Bauer; Robert N Jones
Original assignee: Bowles Engineering Corp
Current assignee: Bowles Engineering Corp
Priority date: 1968-03-20
Filing date: 1968-03-20
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12

Abstract

A pair of substantially opposed nozzles issue respective input fluid streams along a common wall extending from a sidewall of each of the nozzles. A wedge shaped protrusion is formed in the wall approximately midway between the nozzles, the protrusion serving to impart a velocity component normal to the wall to each of the input streams. The streams interact in the region of the protrusion producing a resultant stream having an angular direction with respect to the wall which depends upon the pressure differential between the two input streams. Alternatively the resultant stream may be deflected by control stream to represent a measure of control stream strength.

Description

7 United States Patent Inventors Appl. No.

l-iled Patented Assignee Peter Bauer Germantown, Md.; Robert N. Jones, Wallingi'ord, Conn. 714,683

Mar. 20, 1968 Jan. 12, 1971 Bowles Engineering Corporation Silver Spring, Md.

a corporation of Maryland COMPARATOR AMPLIFIER 20 Claims, 3 Drawing Figs.

Int. Cl. Field of Search UNITED STATES PATENTS 3/1966 Bowles 137/s1.s FlSc 1/14 137/8l.5

References Cited 3,277,915 10/1966 Dockery 137/8l.5 3,366,131 1/1968 Swartz 137/8l.5 3,435,837 4/1969 Sher 137/81.5 3,444,876 5/1969 Sieracki et a1. 137/81.5

Primary Examiner-Samuel Scott Attorney-l-lurvitz, Rose & Greene ABSTRACT: A pair of'subs tantially opposed nozzles issue respective input fluid streams along a common wall extending from a sidewall of each of the nozzles. A wedge shaped protrusion is formed in the wall approximately midway between the nozzles, the protrusion serving to impart a velocity component normal to the wall to each of the input streams. The streams interact in the region of the protrusion producing a resultant stream having an angular direction with respect to the wall which depends upon the pressure differential between the two input streams. Alternatively the resultant stream may be deflected by control stream to represent a measure of control stream strength.

PATENITEUJAN 1 2 m INVENTORS PETER BAUER 6n ROBERT M J ones )fl/w ATTORNEYS g g m:

E x mm mm J x mm l p fin. g M T m 00 q i A v 5:31:5 )w/ mm i w M v 3 a I v COMPARATOR AMPLIFIER BACKGROUND or THE INVENTION power stream of fluid relative to an output passage. Where pressure is the parameter'being amplified, the width of the output passage is made small relativeto the width of the power stream and the transverse portion of the power stream received by the output passage is dependent upon the relative moment of the control and power streams. The gain is equal to the change in output pressure divided by the change in control stream pressure producing the output measure change. It is readily seen therefore that for a given amplifier configuration the transverse pressure gradient of the power stream is a limiting factor with respect to pressure gain of the amplifier since it is this pressure gradientwhich determines the pressure of the fluid received at the output passage'for a given power stream deflection. The limitation on gain imposed by the power stream transverse pressure gradient is often a severe disadvantage where high gain applications are involved.

Another characteristic of the stream interaction type pure fluid amplifier which limits its use in certain applications is its somewhat limited dynamic operating range. Specifically, where control streams of high pressure levels are to be employed, correspondingly high power stream pressures are required in order that the amplifier not be too readily saturated. Where both the control stream pressure and power stream pressure are relatively high, sensitivity to low level pressure changes in the control signal decreases correspondingly.Moreover, increasing power stream pressure beyond a predetermined level tends to-produce power stream turbulence which results in nonlinearities in the'amplifier gain characteristic. 7

Another prior art pure fluid amplifier is the turbulence amplifier, an example of which may-be found in US. Pat. No. 3,234,955 to Anger. In the turbulence amplifier a normally laminar power stream is received at an output passage, the power stream being rendered selectively turbulent as a function of a control stream directed to intercept the power stream. The pressure level of the control stream must be maintained sufficiently low as to avoid deflection of the power stream but sufficiently highso as'to produce turbulence effects at the output passage which are monitorable. his clear that the dynamic operating range of input pressures for the turbulence amplifier is severely limited.

bient conditions with ,the result that hysteresis effects are produced in the output signal pressure as a function of the differential input pressures. Further, the devices are quite noisy.

It is an object of the present invention to provide a single pure fluid amplifier which is substantially devoid of the abovedescribed disadvantages inherent in prior art pure fluid amplifiers.

It is another objectv of the present invention to provide a compact pure fluid amplifier having a relatively high gain. large dynamic operating range of pressures, and high-pressure recovery characteristics as compared with prior art pure fluid amplifiers.

Another problem with prior artpure fluid amplifiers concerns devices having one or more stable conditions. Specifically, the boundary layer type pure fluid amplifier employs the boundary layer lock-on phenomenon wherein a power stream is caused to lock-on to one or the other of a pair of sidewalls of a chamber or output passage, the power stream being directed to an appropriate output passage as afuriction of the wall or walls to which it is attached. In order-for the power stream to be switched from its position of lock-'on to'a sidewall, the force required to provide such switching (for example as provided by a control stream interacting with the power stream) must be large enough not only to deflect the power stream itself, but also to overcome the lock-on forces resulting from the boundary layer lock-on phenomenon. The switching sensitivity of such a device is therefore inherently relatively low.

It is another objectof the present invention to provide a switching-type pure fluid amplifier which has inherently greater switching sensitivity than prior art pure fluid devices.

SUMMARY OF THE INVENTION into theinteraction region from thewall so as to impart transverse velocity components to each input stream and constraining the streams to interact in the immediate vicinity of the wedge rather than at some variable location transversely thereof. The interaction of the input streams produces a flow or pressure output signal as a function of the relative strength'of the input streams. As described in the referenced Bjornsen patent, the impact modulator approach does tend to .provide relatively high gain as a function of changes in input pressure differential, and its dynamicoperating range of input pressures is relatively large. However, there are a number of disadvantages inherent in the conventional impact modulator approach which render it unsuitable for many applications.

Specifically, the impacting streams create a region of equilibrium or zero dynamic pressure at a location which is dependent upon the relative strengths of the streams, this location being variable as the input streamparameters vary. In-

order that a relatively large dynamic operating range of input pressures be accommodated, a relatively large device must beresultant force power stream configuration or theinter'acting resultant stream which is effectively pivoted about the protrusion and has a direction depending-upon the relative momenta of the two input streams. One or more output passages are disposed at the downstream end of the interaction region to receive the resultant stream as a function of the input pressure differential.

In another aspect of the present invention, the abovedescribed amplifier has-both input nozzles connected toka common pressure source. The resultant streammay-thenbe considered a power stream'which can be deflectedbycontrol streams from additionally provided control nozzles as is conventionally done in stream interactiontype pure fluid amplifiers. However, the resultant-power stream in thepresent configuration is inherently more sensitive to deflectiortby control streams than the power stream in conventional =pure fluidamplifiersfor thereason that the power stream of the present invention is a resultant stream established in a balanced force system. A very slight unbalance in-the system, such as will be provided by an additional control stream provides relatively large power stream deflection in responseito'a control stream signal. In conventional pure fluid amplifiers, on

the other hand, the power stream is not a-resultant of balanced forces, but rather a stream having substantially only unidirectional components.

Eitherof the configurations discussed above, namely the input signal configuration may be readily employed as'either an analogue or switching pure fluid device. Theresultant output stream in both configurations is proportional to the sum of the forces applied to the unit, and appropriate numbers of output passages can be positioned in accordance with a desired operational mode for the amplifier.

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 drawing, wherein:

FIG. 1 is a plan view of one embodiment of the pure fluid amplifier of the present invention;

FIG. 2 is a plan view of a second embodiment of the pure fluid amplifier of the present invention; and

FIG. 3 is a block diagram of an analogto-digita'l converter utilizing the amplifier illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 of the accompanying drawings, there is illustrated a pure fluid amplifier constructed in accordance with the principles of the present invention. The cavities, passages, and noules comprising pure fluid amplifier 10 may be formed in a flat plate 11 which may be covered by flat plate 12, the two plates being sealed in fluid-tight relationship and being illustrated as composed of a clear plastic material for purposes of facilitating an understanding of the present invention. It should be understood, however, that other forms of fabrication may be employed and that any material compatible with the working fluid employed may be used in the construction of the amplifier 10.

Amplifier 10 comprises a pair of substantially

opposed input nozzles

13 and 15 communicating with an interaction chamber or region 17. The downstream end of chamber 17 is defined by a wall 19 formed by extending a sidewall of each of

nozzles

13 and 15 into chamber 17. As viewed in FIG. 1, the lower sidewalls of the two

input nozzles

13 and 15 are extended to form the wall 19. Five

fluid passages

21, 23, 25, 27, and 29 communicate with chamber 17 in respective clockwise positions positions between input nozzles 13 and 14 15 as viewed in FIG. 1. Although the inventive concept disclosed herein should not be construed as so limited, amplifier 10 is constructed symmetrically about its longitudinal centerline which extends longitudinally through passage 25. Thus input

nozzles

13, 15 and passage pairs 21, 29 and 23, 27 are symmetrically disposed about passage 25.

A small wedge-shaped protrusion 31 extends from wall 19 into interaction region 17. Protrusion 31 is positioned symmetrically about the longitudinal centerline of the amplifier 10 and extends sufficiently into chamber 17 as to impart flow components to streams issued by

nozzles

13 and 15 which are perpendicular at least to normal flow from these nozzles. It has been found that the protrusion 31 would be smaller than the width of

input nozzles

13 and 15 if gain (that is, deflection changes of the resultant stream as a function of changes in relative input pressure) is the important consideration; however, it is conceivable that the protrusions may be extended further into the interaction chamber where other considerations, such as pressure recovery, are paramount.

In one mode of operation the amplifier 10 of FIG. 1 may be provided with the following connections:

nozzles

13 and 15 are connected to differentially varying input pressure sources; passages 21 and 29 are vented to ambient pressure;

passages

23 and 27 are connected to a utilization, measuring or indicating device; and passage is vented to ambient pressure. It is to be understood that these connections are for a particular operational mode of amplifier l0, and that one or more of

passages

21, 29 and 25 may serve as additional output passages. In operation, protrusion 31 deflects the input streams issued by input noules l3 and 15 proportionally in accordance with their pressures. The amount of deflection to be imparted by the protrusion for a given input pressure depends on the downstream configuration of amplifier 10, namely the side of interaction chamber 17, the widths of the various passages, etc., and protrusion 31 is proportioned accordingly. Protrusion 31 assures that both streams interact immediately in the vicinity of the protrusion rather than on either side of it as the pressure differential across

noules

13 and 15 varies. The interaction of the input streams produces a resultant stream which depends for its direction on the difference in momenta of the two input streams, the resultant stream effectively originating at protrusion 31 so as to be pivoted about the protrusion as a function of input pressure changes. When the pressures at

nozzles

13 and 15 are equal, since the amplifier 10 is symmetrical about its center line, the net interacting forces of the two streams balance and the resultant stream is directed through passage 25 which, in the example described above, is vented to ambient pressure. As the input presure differential changes the resultant stream is rotated about protrusion 31 accordingly so that

output passages

23 and 27 receive correspondingly more or less of the stream.

The direction of the resultant stream is extremely sensitive to changes in the input pressure differential. The reason for this is that a force balance system is quite sensitive to any force change in the system. Consequently a system in equilibrium is very sensitive to even a slight unbalance or force change, and therefore even a slight change in either of the input stream pressures effects a relatively substantial change in the equilibrium position for the resultant stream. A unit scaled exactly to the configuration illustrated in FIG. 1, when subjected to tests exhibited a pressure gain of the order of 6 (gain being defined as changes of the differential pressure across

output passages

23 and 27 as a function of changes in the differential pressure applied across input nozzles 15 and 13). Higher order gains are achievable by varying the amplifer configuration, such as by decreasing the size of interaction chamber 17, changing the position and size of the outlet passage, etc. Gains on the order of those disclosed in the above-referenced Bjornsen patent for the impact modulation should be achievable. Pressure recovery in the unit tested was 66 percent. Since no power nozzle or associated structure was required, the unit is comparatively small.

A unit configured similar to that illustrated in FIG. 1, but having protrusion 31 removed was tested, with the result that gains were down by as much as one-half from the gain of the protrusion type unit, with pressure recovery and dynamic range suffering considerably.

It should be clear to those skilled in the art that the underlying concept of the present invention is suitable for constructional arrangements which vary somewhat from that in FIG. 1. Specifically, asymmetrical configurations may be employed where the input signal from either of

nozzles

13 and 15 is to be weighted. Examples of such asymmetrical construction would be transverse displacement of protrusion 31 along wall 19, rotational displacement of the various vent and output passages about protrusion 31, different sized input noules 13 and 15, etc. Furthermore, it should be clear that three-dimensional configurations are possible wherein amplifier 10 may be considered a surface of revolution about its longitudinal center line or about an axis perpendicular to the longitudinal centerline and displaced slightly below the wall 19 as viewed in FIG. 1, or other convenient axes. Further, any number of output passages may be provided in accordance with the particular application in which the amplifier is to-be employed.

In addition to its utilization as a proportional type amplifier, pure fluid amplifier 10 of FIG. 1 may also be employed as a digital logic element. Specifically, if bilevel, or binary fluid streams are applied to the input ports or

input nozzles

13 and 15, and protrusion 31 is configured to direct a stream issued from nozzle 13 away from wall 19 and into output passage 27 and to direct a stream issued from nozzle 15 away from wall 19 and into output passage 23, a multifunction logic circuit is provided. The

passages

23 and 27 may be connected to a common passage provided a signal representing the exclusive OR function, that is a signal present when either, but not both, of

input passages

13 and 15 receive a binary-one input signal. When both

nozzles

13 and 15 receive binary one input signals the resultant stream is directed to center output passage 25 which thereby provides a signal representative of the AND logic function. It will be evident to those-of ordinary-skill in the art that various other logic functions-may be provided by units similar to pure fluid-amplifier 10 by simply providing appropriate output passages. interrelatedwith the directivity of wedge-shaped protrusion 31. Similarly,-vent passages 21 and 29 may be removed and replaced by appropriate sidewalls for region 17. This latter configuration permits boundary layer lock-on effects to be utilized to accomplish logic functions in a manner similar to power stream-type devices. 1

Referring now specifically to. FIG: 12, there is illustrated another embodiment of the present'inventiomA pair of input passages 53 and 55'communicate with interaction chamber. or

region 57,'nozzles 53 and 55being substantially opposed at the downstream endof chamber.57.- Communicating with interaction chamber 57 in clockwise sequencefromnozzle 53 to nozzle 55' asviewed in FIG. 2 are ventpassage 51, output passage 63, output passage 65, and input-

passages

67, 69, 71" and 72. The various passages sequentially recited are separated by conventional wedge-shaped flow dividers having their apices-bordering the interaction chamber 57. Flow divider 75, which separates

output passages

63 and 65,has a generally semicircular recess 77 formed. at its apex, recess 77 terminating at its extremities in cusps 79 and 8l adjacent

respective output passages

63 and 65. A further venting passage 83 communicates with output passage 65 downstream of chamber 57 and a passage 85 communicates between vent passage 61 and output passage 63 downstream of chamber 57. A wedge-shaped protrusion 91 extends from wall 59' into chamber 57 in a manneranalogous to the extension of protrusion 31 of the chamber 17 in FIG. 1. Input nozzles 53' and 55 are connected to a common input passage 93.

Wedge-shaped protrusion-9l is in substantial alignment with cusp 81. When equal flow is provided. by

nozzles

53 and 55 so that a resultant stream is produced normal .to "wall 59, the-main portion of the resultant stream is directed towards output passage 65. The leftmost portion of the resultant stream, however, as viewed in FIG. 2,;is scooped or peeled off by cusp 81 and diverted by semicircular recess 77. Someof the fluid thusly diverted is directed backlagainst the left sideof the resultant stream to'further deflect'thestream into output. passage 65. Other portions of the diverted fluid are vented to ambient pressure via

passages

61 and 85.

The egress orifices .of respective input passages are'directed to issue fluid streamsgenerally towardlto the. pivot ipoint'or point of interaction between the stream issued from nozzles 53: v and 55. This is done to maximize the effects of the input control streams on the balanced force resultant power stream and thereby enhance the sensitivity of amplifier 50. For someapplications of course the input passages may be otherwise directed. L v Y In operation input passage 93' is connected toa source of constant pressure fluid and if input nozzles53and 55 are. identically configured and symmetrically disposed about wedge-shaped protrusion 91, a resultant power stream flow is produced which is directed towards output passage 65.-

If an input signal is received in the-form of a fluid control result from the presence-of one or more input signals at

input passages

67, 69, 71 and .73. Thus, relatively low energy is required of the inputcontrol streams from: these passages to produce deflection of the power stream. This. of course. increases the fan-out capabilities of the preceeding'stages which produce these input signals.

The particular configuration for amplifier 50 illustrated in FIG. 2 is an OR/NOR gate having four inputs wherein a NOR output signal is provided in passage 65 whenever none of the

input passages

67, 69, 71, 73 receive input signals and output passages 63 provides an OR output signal whenever an input control signal is provided by any of the input passages. Of course, by appropriately positioning the input and output passages various other configurations'utilizing the balanced force power stream concept can be constructed by those skilled in theart so as to produce desired logicfunctions. In addition, it is to be understood that for-certain applications the resultant power stream need not be quiescently directed perpendicular to wall 59; that is, in the absence of control signals. it may be desirable to direct the power stream at some angle other than 90 relative to wall 59. This may be readily accom vplished by displacing

nozzles

53 and 55 asymmetrically with stream from any of input passages 67,'.69, 71 or 73' the resultant power stream is deflectedftowards outputpassage I 63. When so deflected, the right-hand portion of the deflected stream, as viewed in FIG. 2, is scoopedor peeledoff by cusp 79 and diverted by semicircular recess 77. A portion of the: diverted fluid acts against the right-hand portion of the.

deflected power stream to maintain the power stream directed" toward output passage 63; the remaining portion of the" diverted fluid is vented by meansof venting passage 83'com-- municating with output passage 65. v

Because the power stream of device 50 is the resultant in a balanced force system, the angular position of the power stream is extremely sensitive to anyforce unbalance aswould respect to protrusion 91 or by providing these nozzles'with unequal flow characteristics or by directing the cusp other than at relative to the wall 59.

Amplifier 50 of FIG. 2 may be converted to a proportional or analogue amplifier by replacing the semi'spherical recess 77 l and cusps 79 and'8l with a conventional wedge shaped divider similar to those dividingthe'otherpassages in-amplifier 50. As an analogue amplifier, amplifier 50 produces highly sensitive power stream deflection as a function of an analogue pressure range has hamperedpriorart attempts at providing:

purefluid analog-todigital converters. The utilization-of pure fluid amplifier 10. as a comparator has solved the prior art problems in this regard. An analogue input pressure signal is provided. to a comparator which may be similar or identi cal to fluid amplifier 10 of FIG. 1. The pressure differential output signal of comparator 110" is .then applied as ari'input signal to a digital signal generator 111. Digital signal generator Ill-may be'a conventional priorart device which'respondsto pressuredifferential to provide. a proportional digital output signal. For example, digital signal generator 111 may comprise a pair of pressurecontrol oscillators feeding a respective pair of spillover counters; the input signals'to tlie pressure'co'm trolled oscillators being output passages 23 and 27'ofamplifier l0of FIG. 1, for example. A digital register'for comparingthe' 1 counts in the. two counters may then :be-employed to provide the digital output signal of the device'rAdigital signal 'genera-' tor such as this is disclosedv in copending patent applicatio'n U.S. Pat. Ser. No. 500,977 by Edwin Ml-Dexter, entitl'ed- Vortex Readout System" andassigned-to the same assignee-as the present invention. Thedigital output signal-from-generator 111 'is applied to a conventional digital to analogue-converter unit: 113, the analogue output signal' from which is fed baclcas a further input signal to comparator 110':

'Control systemssuch as the one illustrated in FIG? 3'- are per se conventional. But prior 'to the present invention sensitivity operating range and a high sensitivity.

While we have described and illustrated several specific em 'bodiments of our invention, it will be clear that'variation of the details of construction which are specifically illustratedspirit and scope of the inverTo'nas defined in the appended claims.

I claim:

1. A pure fluid element comprising:

a wall;

means for establishing a pair of opposed input fluid streams along said wall;

protruding means extending from said wall for deflecting said input streams away from said wall and into interacting relationship with one another to provide a resultant stream;

control means for varying the angular position of said resultant stream about said protruding means; and

output means for receiving varying portions of said resultant stream as a function of its angular position.

2. The combination according to claim 1 wherein said control means includes means for varying the strength of at least one of said input streams.

3. The pure fluid element according to claim 2 wherein: said wall defines the upstream end of an interaction chamber; said means for establishing comprises a pair of opposed nozzles for issuing said input streams; said protruding means comprises a substantially wedge-shaped member extending from said wall into said interaction chamber; and said output means comprises at least one fluid output passage communicating with said interaction chamber downstream of said opposed nozzles.

4. The pure fluid element according to claim 3 wherein said substantially wedge-shaped member extends from said wall to a distance which is a smaller than the width of said opposed nozzles.

5. The pure fluid element according to claim 3 wherein said output means further comprises another fluid output passage communicating with said interaction chamber downstream of said opposed nozzles, said one and another fluid output passages providing an output pressure differential as a function of the pressure differential across said opposed nozzles.

6. The pure fluid element according to claim 5 further comprising means for venting said interaction chamber to ambient pressure.

7. The pure fluid element according to claim 1 wherein said control means includes'at least one control nozzle for selectively issuing a control stream in interacting relationship with said resultant stream.

8. The pure fluid element according to claim 7 wherein: said wall defines the upstream end of an interaction chamber; said means for establishing comprises a pair of opposed nozzles connected to a common source of fluid pressure for issuing said input streams; said protruding means comprises a substantially wedge-shaped member extending from said wall into said interaction chamber; and said-control means comprises at least one output passage communicating with said interaction chamber downstream of said opposed nozzles.

9. The pure fluid element according to claim 8 wherein said output means further comprises another output passage communicating with said interaction chamber, said one and said another output passages being separated by a flow divider having walls diverging outwardly from said interaction chamber, said flow divider having a concave region formed in the end thereof facing said wall, said concave region defining a pair of cusps adjacent a respective output passage, the cusps being directed toward said wall and located such that a portion of the resultant stream received by each output passage is peeled off by a respective cusp and diverted by said recess into interacting relation with the resultant stream.

10. The pure fluid element according to claim 1 wherein: said wall defines the upstream end of an interaction chamber; said means for establishing comprises a pair of opposed nozzles for issuing said input streams; said protruding means comprises a substantially wedge-shaped member extending from said wall into said interaction chamber; and said output means comprises at least one fluid output passage communicating with said interaction chamber downstream of said opposed nozzles.

11. The pure fluid element according to claim 10 wherein said control means includes means for varying the pressure in the region at which said input fluid streams interact.

12. A fluidic element, comprising:

a wall having a surface;

means for establishing a pair of opposed fluid streams along said surface; and

reference-point means protruding from said surface for deflecting said opposed fluid streams away from said surface and into interacting relationship with one another to form a resultant fluid stream directed from said reference-point means at an angle relative to said surface said angle being a function of the relative strengths of said opposed fluid streams.

13. The element according to claim 12 further comprising output means for receiving varying portions of said resultant fluid stream as a function of the angle made by said resultant fluid stream relative to said surface.

14. The fluidic element according to claim 12 further comprising means for selectively varying the relative strengths of said opposed fluid streams.

15. The fluidic element according to claim 12 wherein said protruding means is a substantially wedge-shaped member having an apex extending from said surface to a distance which is less than the transverse dimension of either of said opposed fluid streams.

16. The fluidic element according to claim 12 further comprising control means for selectively deflecting said resultant fluid stream.

17. The fluidic element according to claim 16 wherein said control means comprises means for issuing a control stream of fluid into interacting relationship with said resultant fluid stream.

18. A fluidic element, comprising:

a wall having a surface;

means for establishing a pair of opposed fluid streams along said surface;

reference-point means protruding from said surface at a fixed location relative to the rest of said fluidic element for deflecting said opposed fluid streams away from said surface and into interacting relationship with one another to form a resultant fluid stream; and

output means for receiving varying portions of said resultant fluid stream as a function of the relative strengths of said opposed fluid streams.

19. The element according to claim 18 further comprising means for selectively deflecting said resultant fluid stream.

20. The element according to claim 18 wherein: said surface defines the upstream end of an interaction region; said means for establishing comprises a pair of nozzles arranged to issue respective ones of opposed streams along said surface; and said output means includes at least one fluid passage having an ingress opening communicating with said interaction region downstream of said pair of nozzles.

Claims

1. A pure fluid element comprising: a wall; means for establishing a pair of opposed input fluid streams along said wall; protruding means extending from said wall for deflecting said input streams away from said wall and into interacting relationship with one another to provide a resultant stream; control means for varying the angular position of said resultant stream about said protruding means; and output means for receiving varying portions of said resultant stream as a function of its angular position.

7. The pure fluid element according to claim 1 wherein said control means includes at least one control nozzle for selectively issuing a control stream in interacting relationship with said resultant stream.

8. The pure fluid element according to claim 7 wherein: said wall defines the upstream end of an interaction chamber; said means for establishing comprises a pair of opposed nozzles connected to a common source of fluid pressure for issuing said input streams; said protruding means comprises a substantially wedge-shaped member extending from said wall into said interaction chamber; and said control means comprises at least one output passage communicating with said interaction chamber downstream of said opposed nozzles.

12. A fluidic element, comprising: a wall having a surface; means for establishing a pair of opposed fluid streams along said surface; and reference-point means protruding from said surface for deflecting said opposed fluid streams away from said surface and into interacting relationship with one another to form a resultant fluid stream directed from said reference-point means at an angle relative to said surface said angle being a function of the relative strengths of said opposed fluid streams.

18. A fluidic element, comprising: a wall having a surface; means for establishing a pair of opposed fluid streams along said surface; reference-point means protruding from said surface at a fixed location relative to the rest of said fluidic element for deflecting said opposed fluid streams away from said surface and into interacting relationship with one another to form a resultant fluid stream; and output means for receiving varying portions of said resultant fluid stream as a function of the relative strengths of said opposed fluid streams.