US3053276A - Fluid amplifier - Google Patents

Description

Sept. 11, 1962 K. E. WOODWARD FLUID AMPLIFIER 2 Sheets-Sheet 1 Filed April 26, 1961 FIG. IA

INVENTOR Kenna/h E Woadwora Mdavm Sept. 11, 1962 K. E. WOODWARD FLUID AMPLIFIER 2 Sheets-Sheet 2 Filed April 26, 1961 INVENTOR Kenna/h E Woodward 3,053,276 FLUID AIVEL LHEFEER Kenneth E. Woodward, 2526 Hunting Ava, ltlcLean, Va. Filed Apr. 1%, 1961, "er. No. ltlifeZfl 9 Qlaims. (Qt. 13'7-59'7) {Granted under Title 35, US. (lode (H52), see. 265) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates generally to fluid amplifiers which utilize the flow of a fluid so that a control input fluid signal is amplified.

More specifically, this invention relates to a fluid amplifier which employs a pivotable flow divider blade as the only moving part in order to overcome the problem of erroneous output signals resulting from heavy backloading of the amplifier. Fluid amplifiers of the type which do not require any moving elements utilize a fluid stream, hereinafter referred to as the power stream, which issues from a nozzle or orifice constructed such that the power stream is well defined. A control fluid stream is directed toward the power stream in a direction substantially perpendicular thereto in order to provide a diiferential pressure or pressure gradient across the power stream. The amplifier is provided with at least two outlet or fluid receiving apertures or passages facing the power stream, and the fluid receiving passages are arranged such that the power stream can be deflected by the control stream into one or the other of the passages. Suitable load devices communicate with these passages. Since this type of fluid amplifier requires no moving parts the designation of these amplifiers as pure fluid is seen to be valid and appropriate.

The control stream being directed generally transversely of the power stream, an interaction occurs between the two streams, resulting in deflection of the power stream to an extent, that is, through an angle, which is related to the momentum of the control stream. Deflection of the power stream results in delivery of a portion of the power stream to the second aperture where some of the kinetic energy of the power stream entering the second aperture may be recovered, or where the fluid so directed may be delivered to an appropriate utilization device. It has been found that a low energy control stream can deflect a well-defined, high energy power stream to the extent required to cause a substantial portion or all of the power stream to be delivered to the second output passage, and that the integrity of the power stream is retained sufficiently after interaction of the two streams that the total energy or change in total energy delivered to the second passage can be greater than the energy or change in energy required by the control fluid to accomplish this deflection. Thus, since the changes in ener y at the load device produced by deflection of the stream are greater than the changes in energy required to produce the deflection, the apparatus is capable of amplification, and a power gain is realized.

A fluid amplifier of the type described above usually comprises a power nozzle extending through an end wall of a chamber defined by the end wall and two outwardly diverging side walls, hereinafter referred to as the left and right walls. A fixed V-shaped or aerodynamically Patented fiept'. 11, 1962 streamlined divider is disposed at a predetermined distance from the end wall, the apex of the divider being located along the center line of the power nozzle sides of the divider are generally parallel to the left and right side walls of the chamber. The regions between the divider and the left and right side walls define left and right outlet passages respectively. One or more left control nozzles extending through the left wall, or one or more right control nozzles, or a combination of right and left control nozzles are provided, each control nozzle being positioned and directed transversely to the power nozzle.

In operation, fluid under pressure is supplied to the power nozzle and a well defined fluid stream, the power stream, issues into the chamber. Control signals in the form of changes in pressure or flow rate are developed at the control nozzles and the control streams issuing from or flowing into these nozzles produce deflection of the power stream in one direction or the other depending upon whether the signal is in the form of increased or decreased pressures, or flow rates respectively.

One of the main disadvantages of known pure fluid 1 amplifiers is that under severe or heavy backloading conditions the back pressure developed in the passage from which the stream is flowing may become so great that stream will be forced to flow back upon itself and around the tip of the divider to exit from the other output passage. Since this would occur in the absence of an appropriate control signal from an opposed control nozzle, the amplifier will produce an erroneous output signal.

By the addition of one moving part I have discovered that it is possible to ensure fluid flow from that output passageway into which the power stream has been deflected by control fluid flow even though there is severe backloading of that aperture. This part is the flow splitter or divider blade which is normally employed in fluid amplifiers to split the fluid flow from the power nozzle into one of two or more output apertures.

According to this invention, pure fluid amplifiers are modified by the addition of a pivotally mounted flow splitter or divider blade. The tip of the blade extends to a point where it can be acted upon by impinging fluid streams from either of the control nozzles as well as the power stream. The divider will be pivoted by the control stream of greatest momentum or energy level and direct all fluid flow from the power nozzle into that aperture which is associated with the control nozzle issuing the greater energy level fluid signal. Heavy backloading of that aperture merely increases the pressure holding the divider in its pivoted position and no fluid will enter an adjacent aperture from whence it could give an erroneous output signal.

Broadly therefore, it is an object of this invention to provide a fluid amplifier which will issue all the fluid from the proper aperture even though that aperture is heavily backloaded.

Another object of the present invention is to provide a fluid amplifier having a pivotable divider blade, the position of which being governed by the differential in magnitude of control fluid flows applied transversely of the direction of flow of the fluid stream and against the tip of the blade.

It is another object of the present invention to provide a fluid amplifier system employing a pivotable divider blade, the position of which being governed by a main stream of fluid and a diflerential in control fluid flow applied transversely of the direction of flow of the main stream.

It is yet another object of the present invention to provide a fluid amplifier having a pivotable divider blade in which amplification depends upon the magnitude of deflection of a main stream of fluid by a control fluid stream and in which the main stream caused to flow into one of two outlet passages depending upon the position of the divider.

Still another object of the present invention is to provide a fluid amplifier employing a pivotable divider blade, in which amplification depends upon the magnitude of the deflection of a fluid stream issuing from a power nozzle and in which control fluid flow impinges against and in conjunction with the power jet pivots the divider blade so that all the fluid from the power nozzle enters one of the output passages and continues to flow therethrough even though that passage is heavily backloaded.

Another object of this invention is to provide a pivota-ble divider blade in a fluid amplifier the divider preventing a relatively lower magnitude fluid signal issuing from one control nozzle from entering the same output passage as the main stream of fluid enters.

Still another object of this invention is to utilize the pivoting of a divider blade to actuate other mechanisms or devices.

The specific nature of the invention, as well as other objects, uses and advantages thereof, will clearly appear from the following description and from the accompanying drawing, in which:

FIG. 1 is a partial sectional plan view of a conventional fluid amplifier modified in accordance with the invention.

FIG. 1A is a partial sectional view of the fluid amplifier illustrated in FIG. 1, showing the divider blade in a deflected position.

FIG. 2 illustrates a partial sectional view of another embodiment of my invention showing the divider blade in one position.

FIG. 2A is a partial sectional view of the amplifier illustrated in FIG. 2, showing the divider blade in another position.

FIG. 3 illustrates a valving system actuated by pivotal movement of the divider blade shown in FIG. 1.

Referring now to FIG. 1, fluid amplifier is formed by three flat plates 11, 12 and 13. Plate 12 is positioned between plates 11 and 13 and is tightly sealed between these plates by machine screws 14. Plates 11, 12 and 13 may be composed of any suitable material such as metal, ceramic or plastic. Also any suitable means may be employed to hold the three plates together, machine screws 14 being merely illustrative of one means. For purposes of illustration the plates are shown composed of a transparent plastic material such as lucite. Plates 11 and 13 prevent spreading of the power and control streams received by amplifier 10 in a direction normal to the deflecting plane.

The substantially Y-shaped configuration cut or etched from plate 12 provides a power nozzle 15, control nozzles 16 and 17, and fluid receiving passageways l8 and 19. Nozzles 15 and 16 are adjacent each other and are at substantially right angles. Control nozzle 17 is positioned opposite nozzle 16.

Output tubes and 21 are threadedly connected to the ends of passageways 18 and 19 for receiving fluid therefrom. Suitable load devices (not shown) may be connected to tubes 20 and 21 as will be apparent to those in the art. Tube 22 is threadedly connected to power nozzle 15 while tubes 23 and 24 are threadedly connected to control nozzles 16 and 17, respectively. The connections between the tubes and the nozzles as well as the tube connections to the apertures should be made tight enough to prevent leakage.

Sources of pressurized fluid 3t), 31 and 32 are connected to tubes 22, 23 and 24. The fluid utilized by ampilfier 10 may be air, gas, water or other liquids. The gas and liquid may have small solid particles or bubbles entrained therein, or source 30 may consist of a pressurized liquid while sources 31 and 32 consist of pressurized gas, or vice versa. Fluid regulating valves 34 and 35 may be positioned in tubes 23 and 24 to vary the fluid flow through these tubes. Such valves may be driven by condition responsive mechanisms 36 and 37 which may take the forms of switches, relays or solenoids.

Since control nozzles 16 and 17 are in opposed relationship variation in fluid pressure or flow in either nozzle will cause amplified displacement or movement of the power jet issuing from nozzle 15 in accordance with momentum exchange or beam deflection principles. These principles have been disclosed in the June 1960 issue of Science and Mechanics Magazine, pages 81-84 and are now well known in the art.

As discussed above, a serious disadvantage of prior art fluid amplifiers is that when output tubes 29 and 21 are heavily backloaded, as for example by severely valving the output, the stream flowing through a passageway 18 or 19 may be forced back upon itself until it flows out the wrong passage. As a consequence, an erroneous output signal will issue from amplifier It Pivotable divider blade 40 is employed in accordance with the present invention to remedy this problem. A substantially circular opening 41 is cut from plate 12. Bulb-shaped end 42 of blade 40 fits into opening 41 with suflicient clearance to permit to pivot. Tip 43 extends almost into contact with edge 44 and will alternately substantially cover the orifices 45 and 47 of nozzles 16 and 17 as blade 40 pivots from the centerline position of FIG. 1, where tip 43 is aligned with the center of orifice 46 in nozzle 15. The depth or thickness of the blade is substantially equal to the depth or thickness of plate 12 so that fluid signals from the control nozzles will impinge against the sides of tip 43. The direction of pivotal movement of blade 40 will be governed by the control signal having the greatest magnitude. The blade should be made thin enough to swing between chamber walls 48 and 49.

If the fluid control signals issuing from the control nozzles 16 and 17 are of equal magnitude the power jet from nozzle 15 will be split in half by blade 40. The blade will assume the position as shown in FIG. 1. If control nozzle 16 issues the greater control signal blade 40 will pivot clockwise as shown in FIG. 1A as a resul of fluid from the power nozzle 15 being deflected to impinge against the right side of tip 43. All flow from the power nozzle enters passage 18. Any flow from nozzle 16 will be directed into passage 18. Conversely, when control nozzle 17 issues a fluid signal having a greater magnitude than that issuing from nozzle 16, tip 43 will be driven counter-clockwise with the result that all fluid from nozzle 15 enters passage 19.

As the tip of the divider passes the centerline position where it splits flow from power nozzle 15 equally (FIG. 1), the combined effect of the control stream and the power stream acting against the left side of tip 43 will flip the divider so that tip 43 contacts the edge of orifice 45. While the deflection of the divider blade from wall 49 to the centerline position is primarily eifected by impinging fluid from central nozzle 17. After the blade is driven beyond the centerline position, the deflected power jet from nozzle 15 will aid in providing a considerable additional force against tip 43 so that the tip is driven at considerable speed against wall 48. A flip-flop action between the centerline position and the walls 48 and 449 is thusly achieved.

It will be evident that the more severely the passageway from which the power jet is flowing is backloaded, the greater will be the pressure against blade 40 tending to hold it in its deflected position. Since fluid from each control nozzle impinges against opposite edges of blade 40, and since the blade pivots about end 42 a mechanical advantage is achieved so that the blade has considerable sensitivity to control signals.

As the backloading conditions in passages 18 and 19 become more severe, amplifier will become less sensitive to control signals since more energy from the control nozzles will be required to pivot the divider. Amplifier 1011 (FIG. 2) can be connected to the sources of fluid signals shown in FIG. 1 and is designed to increase the sensitivity of the amplifier to fluid control signals. This is accomplished by extending the walls 50 and 51 which form one side of each passage 18 and 19, respectively, further downwards towards orifice 47 so that walls 5% and 51 isolate the divider blade 52 from the effects of side pressures developed by severe backloading of passages 13 and 19. Divider 52 is pivotally mounted, as is divider 40, and provided with a triangular-shaped tip 53. Tip 53 can swing through a distance approximately equal to the width of orifice 47 of nozzle 15. The distance of swing of tip 53 is governed by the spacing between wall ends 55 and 56 as will be apparent.

Walls 50 and 51 receive substantially all the transverse pressure produced in passages 18 and 19 as a result of heavy backloading conditions. Consequently divider 52 is substantially unalfected by increases in backloading and thus movement of tip 53 is caused only by the combined eifect of the control and power jets acting against the sides of tip 53. FIG. 2A shows the position of divider 52 as a result of control flow from, nozzle 16. As shown in this figure all fluid from nozzle enters passage 18. Fluid from control nozzle 17 will deflect tip 43 to the right as viewed in FIG. 2A thereby causing all fluid from power nozzle 15 to enter passage 19.

Although suitable fluid receiving load devices (not shown) will usually be connected to receive output fluid signals flowing from output tubes and 21, pivotal movement of the divider may also be employed to open or close valves, switches or the like. Referring now to FIG. 3, there is shown a valve 60 having a bore 61 therethrough which can be rotated into alignment with suitable fluid conveying tubes or conduits (not shown) by gears 62 and 63. Shaft 64 connects gear 63 to the pivotally mounted end of divider 40, for example, so that upon pivotal movement of the divider, valve 60 can be rotated. Valve 60 is of course capable of valving fluid flowing at high pressure through conduits, channels or tubes as a result of rotation.

Differentials in pressure in passages 18 and 19 may also be as the sole means for deflecting the divider blade in either of the embodiments shown. In such a case, fluid signals from the control nozzles may or may not be used in conjunction with such pressure differentials. The pressure differentials act against opposite sides of the tip 53 in amplifier 10a, and against opposite edges of divider 40.

While I have shown the power nozzle and control nozzles oriented at substantially right angles to each other in order to illustrate a means of achieving a high gain, it is clear that angles other than right angles may be used. When an angle other than a right angle is used between the power stream and its control stream, the deflection of the power stream and the divider will be determined by the component of the control stream momentum which is at a right angle to the power stream that is, by the component of the force of the control stream which is directed transversely of the power stream and the divider. If only one control nozzle is to be employed the divider blade can be spring biased towards that nozzle.

While I have described and illustrated several 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.

,osaave I claim as my invention:

1. A fluid amplifier comprising: a power nozzle for issuing a fluid stream, a pair of passages receiving said fluid stream from said power nozzle, a pair of control nozzles from which control fluid signals can issue as jets, said jets causing amplified displacement of said stream between said passages, a flow divider pivotally mounted between said passages at one end thereof so as to direct said stream into either passage, said divider being of a length such that fluid control streams impinge against the tip at the other end thereof thereby producing pivotal movement of said divider.

2. The invention as claimed in claim 1, wherein operative means are connected to said one end of said divider so that rotation of said one end actuates said operative means. i

3. A fluid amplifier comprising: a power nozzle for issuing a main fluid stream, a pair of passages receiving said fluid stream from said nozzle, 2. pair of control nozzles from which control fluid signals can issue as jets, said jets causing amplified displacement of said stream between said passages, a flow divider pivotally mounted between said passages so as to direct said stream into either passage, said divider having a length such that fluid control streams impinge against the edges at the free end thereof so as to produce pivotal movement of said divider, means for supplying fluid control signals to said control nozzles, and means for supplying fluid input streams t said power nozzle.

4-. A tfluid amplifier comprising: a power nozzle for issuing a main stream of fluid, a pair of opposed control nozzles for issuing control fluid streams against said main stream so as to cause amplified displacement thereof, a pair of passages positioned to receive fluid from said stream, a flow divider pivotally mounted between said passageways, the tip of said divider extending to substantially cover the orifices of said control nozzle, so that said tip receives impinging jets from said control nozzles, the position of said divider tip being determined by the control stream having the greatest magnitude, said divider blade diverting said main stream into said passages.

5. The invention as claimed in claim 3, wherein said tip is pointed.

6. The invention as claimed in claim 3, wherein said tip is of substantially triangular shape.

7. A fluid amplifier comprising an end wall, a power nozzle formed in said end wall and adapted to issue a main stream of fluid generally perpendicular to said end wall, a pair of outwardly diverging side walls extending from said end wall, a flow divider disposed in the path of said main stream and having outwardly diverging walls, a pair of outlet passages positioned downstream of said power nozzle and adapted to receive fluid therefrom, one end of said divider being pivotally mounted between said passages, the other end of said divider being free and extending into close proximity of said end wall, and at least one control nozzle extending through each of said side walls adjacent said end wall for issuing fluid jets which effect amplified displacement of said main stream.

8. A fluid amplifier comprising: a power nozzle having an orifice for converting streams of fluid supplied thereto as jets, a pair of control nozzles having orifices for converting control fluid streams supplied thereto as control jets against said main stream in such a manner as to cause amplified displacement thereof, a pair of passages positioned to receive fluid from said power nozzle, a flow divider pivotally mounted at one end thereof between said passages, a pair of walls between said divider and said apertures, the ends of said walls extending into proximity to said orifices, a tip formed at the other end of said divider, said tip being substantially triangular in shape and receiving impinging jets from said control nozzles, the apex of said tip being adjacent the orifice of said power nozzle and the position of the tip being determined by the control jet of greatest magnitude, the

7 sides extending from the apex of said tip deflecting flow from said power nozzle into said passages.

9. A fluid amplifier comprising: a power nozzle with an orifice for converting fluid streams received by said nozzle into jets, a pair of passages receiving said jets fr m said power nozzle, a flow divider pivotally mounted at one end thereof between said passages so as to direct the jets into either passage, the other end of said divider being pointed and extending into proximity with said orifice, pivotal movement of said divider being caused by diflerentials in fluid pressure in said passages acting against the sides of the pointed end of said divider, and

References (Jited in the file of this patent UNITED STATES PATENTS 1,755,464 Williams Apr. 22, 1930 2,330,151 Smith Sept. 21, 1943 3,001,698 Warren Sept. 26, 1961 3,016,066 Warren Jan. 9, 1962

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