US3375841A - Fluid device - Google Patents

Description

April 2, 1968 A. SCHONFELD ETAL 3,375,841v

FLUID DEVICE Filed July 29, 1964.

I; 22 H61 15 17a 18a 1 17 2O [/18 12 FLUID E 19b FLUID CONTROL v CONTROL SOURCE a SOURCE 11 FLUID POWER SOURCE IN VENT 0R5 ARNOLD SCHONFELD JOHN C. SCHULTE United States Patent 3,375,841 FLUID DEVICE Arnold Schonfeld, Levittown, and John C. Schulte, Maple Glen, Pa., assignors to Sperry Rand Corporation, New York, N.Y., a corporation of Delaware Filed July 29, 1964, Ser. No. 385,857 4 Claims. (Cl. 137-81.5)

This invention relates to fluid devices, and more particularly relates to a device useful for improving the operation of fluid amplifiers including particularly the output characteristics thereof.

The term fluid amplifier refers to a device wherein, a relatively low energy fluid signal controls a relatively high energy fluid stream. Where this is done without mechanical moving parts, such devices may be termed true fluid amplifiers. The present invention is advantageously employed in either type of fluid amplifiers. It is particularly advantageous with true fluid amplifiers because it introduces no mechanically movable parts. The present specification will be illustrated by true fluid amplifiers, but no restriction thereto is to be implied. Fluid amplifiers employ a fluid stream, hereinafter termed the power stream, which issues from a nozzle suchv that the power stream is well defined. A laterally disposed control fluid stream is directed at the power fluid stream in any of several ways known to the art. In any form, the amplifier is provided with at least two fluid-flow outlet means facing the power stream, and the outlet means are arranged so that the power stream can be deflected by the control stream into any one of the outlet means. The fluid diverted into one or another of said outlet means may be utilized thereby to eflectuate one or another purpose associated therewith. For example, the existence of flow in one of two outlet means may enter a certain character such as a 1 in a register, while the existence of flow in the other outlet means may enter a O in a register. The existence of flow in one of two or more outlets can of course perform many other functions other than this example.

The principle of operation of most such fluid amplifiers is that the viscous or boundary layer forces associated between a moving power stream and a wall or the like within a fluid amplifier will direct it continuously from said power nozzle along one wall and out one of said outlet means, unless and until the power stream is diverted by a control fluid signal so as to leave the first wall and approach and lock onto the second wall, whereby the power stream is diverted out another of said outlet means. Control fluid signals thus determine which of a plurality of outlet means contains a mainstream of fluid-flow.

One important deficiency in all such fluid amplifiers, no matter what form the control fluid signal takes, has been that under severe or heavy backloading conditions the back-pressure developed in the outlet means within which the mainstream is flowing may become so great that the stream may enter the other outlet means, whereupon the power stream may lock-in so that removal of the baclepressure or blockage does not restore the mainstream to its original outlet channel. Since this can occur in the absence of a control signal commanding that it occur, the stream thus channelled through the wrong (i.e., the non-commanded) outlet means constitutes a spurious or false output signal from the fluid amplifier. Worst of all, if lock-in of the power stream has occurred, the mainstream will not then revert to its proper outlet channel even when the excessive back-pressure or blockage is relieved.

Another important deficiency in all such fluid amplifiers, has been that no matter how well directed and defined the power stream issuing from the power nozzle is, the entire stream is seldom deflected into one of the outlet means. Some small proportion of the fluid flow generally finds its way directly (as distinct from by the backup phenomenon) out the non-commanded outlet means, while the mainstream goes out the commanded outlet means. This causes a number of deficiencies. Since the diversion into the wrong channel is generally a function of the flow rate of the power stream itself, the power rating of the device is ultimately limited by this diversion. Also the undesired flow detracts from the contrast between the on condition of one outlet channel, and the off condition of the other, with attendant control-use disadvantages.

It would be highly desirable to prevent back-up, especially back-up that falsely diverts the mainstream to lock-in to the other and wrong outlet channel. It would also be highly desirable to remove the effect of the small fluid stream (even under the condition of no back-up) which finds its way out an outlet means other than the one carrying the mainstream. Both of these phenomena cause inaccuracies in the information conveyed by the outlet stream and thus in the process (e.g., data storage) controlled by the plurality of outlet means.

In the prior art, it has been suggested to prevent these eifects by mechanically actuated means. For example, in US. Patent 3,053,276 to Woodward, issued Sept. 11, 1962, a movable divider blade serves this purpose. However, the real desire in the art is to retain the inherent advantage of true fluid amplifiers, that is, the complete lack of moving parts other than the fluid, and heretofore this has not been possible.

The present invention provides a complete and thorough solution to this problem, in keeping with the need in the art to do so without departing from the fluid amplifier advantage of absence of movable mechanical parts. Moreover, and as a surprising bonus, the solution presented by the present invention additionally provides a memory during back-pressure so that after the back-pressure has subsided, the proper output channel still carries the mainstream, thus affording a non-destructive read-out, that is, a read-out that cannot destroy the state of the fluid amplifier even if it causes back-pressure all the way up to blockage of the on channel.

It is accordingly a principal object of the present invention to provide a new fluid device.

Another object is to provide an improved fluid amplifier.

Another object is to provide means for use with a fluid amplifier whereby no fluid flow exits from an ofl fluid outlet channel when an on channel is carrying the mainstream flow under conditions of no-back-up-.

Another object is to provide an improved fluid amplifier which may be operated at greater power stream ratings because of the absence of derivative false-signal flow in the off channels.

Another object of the present invention is to provide an improved fluid amplifier that aflords high contrast between on and off fluid outlet channels.

Another object is to provide means for preventing inadvertent change of state of a fluid amplifier due to fluid back-up or blockage in a mainstream carrying channel, by a memory feature enabling a non-destructive read out of the on channel.

Still another object is to provide the aforesaid combination of features and attain the aforesaid combination of objectives entirely employing fluid principles alone.

These and other objects and features of the invention will be unfolded during the herein contained detailed description of the invention in physical embodiment form,

which description has reference to the accompanying drawings, wherein like reference characters denote like parts in all views thereof, and wherein:

FIGURE 1 is a schematic representation of a fluid amplifier utilizing an improvement device according to the present invention and showing a portion of the fluid amplifier in sectioned detail,

FIGURE 2 shows an alternative fluid amplifier embodiment to that of FIGURE 1, in corresponding sectioned detail,

FIGURE 3 is a partially sectioned fluid amplifier similar to that shown in FIGURE 1 and employing therewith an alternative embodiment of the improvement device according to the invention, and

FIGURE 4 is a perspective view of a detailed portion of the device of FIGURE 3, showing in detail the intersection of passageways 17a, 18a and 25a of FIGURE 3.

Referring now to the drawings, in FIGURE 1 is shown a fluid amplifier indicated generally within the broken line box at 10, having a power jet passageway 11 leading thereinto, and a pair of fluid control passageways 12 and 13 also leading thereinto. Connected to power jet passageway 11 is a power fluid source 14 adapted to supply a continuous stream of fluid under pressure. Connected to each of fluid control passageways 12 and 13 are fluid control sources 15 and 16 respectively, which sources are adapted to apply fluid pressure at little flow volume. Leading the envelope 10 (that is, the fluid amplifier generally) are outlet passageways 17 and 18 respectively. In these external details, as in the general manner of operation, all true amplifier devices are similar.

The embodiment shown in detail within the envelope 10 of FIGURE 1 employs a power jet orifice 11a which points toward a chamber 19 formed by the intersection of the inner portions of outlet passageways 17 and 18. The size and location of the orifice 11a are arranged so that a jet of fluid emanating therefrom is directed toward the leading edge 20 of the partition dividing and defining the emergence of outlet means 17 and 18 from chamber 19. The dimensions of chamber 19 are arranged so that the power jet emanating from orifice 11a may be diverted to and locked onto either of walls 19a and 19b leading respectively to outlet passageways 17 and 18. In accordance with well-known prior art fluid amplifier practice, viscous forces or boundary layer forces will lock the power jet emanating from orifice 11a onto either of walls 19a or 19b as soon as the said jet touches them, and consequently will lock the said power pet into discharge out of either outlet passageway 17 or 18 respectively. Although it is common to employ lock in of the fluid flow to a wall for stability, it is also known to operate fluid amplifiers without this action, and no restriction of that kind is intended upon use of the present invention.

-In FIGURE 1 is illustrated a first known prior art means for controlling the position of the power jet emanating from orifice 11a so that it contacts either wall 19a leading to outlet passageway 17, or contacts wall 1% leading to outlet passageway 18. That arrangement in FIGURE 1 constitutes the fluid control passageways 12 and 13 which exert selective lateral pressure upon the power jet, thus controlling which of walls 19a and 191) it is directed toward and consequently locked-onto. The US. Patent 3,034,628 issued May 15, 1 962 to W. G. Wadey illustrates and describes this manner of fluid amplifier and further details of construction and operation may be found therein.

The detail shown in FIGURE 2 is in most respects entirely similar to that shown in FIGURE 1 except that the entrance of fluid control passageways 12 and 13 into chamber 19 is not perpendicular to the orientation of the power jet within chamber 19. Instead, the control passageways enter on a curve so as to cause control fluid flow along walls 19a or 1912 respectively and to thereby effect diversion to and locking onto either of those walls by the power jet in a manner further described in detail in US. Patent 3,030,979 issued Apr. 24, 1962 to R. J. Reilly. The principles of the inventive improvements are operable with those two and any other form of fluid amplifier having a plurality of outlet passageways 17 and 18, regardless of the internal details of construction, so long as the device operates upon the fluid amplifier principle.

One important prior art problem with all fluid amplifiers is that the power jet diverted along one of walls 19a or 1% does not travel in its entirety out a single outlet passageway 17 or 18. In theory it should flow out a single outlet 17 or 18, but in practice a small portion of the fluid finds its way out the unintended outlet passageway, while the mainstream flows out the intended passageway. The intended outlet passageway is referred to as the on passageway while the unintended outlet passageway is referred to as the off passageway. The fact that a fluid signal exists in the off passageway at all is a source of trouble in the art. Clearly when a series of fluid amplifiers are employed to control one another the existence of even a small signal in an off passageway can be amplified several-fold throughout the circuit. Moreover, when the off passageway can be expected to have a typical value signal therein the equipment controlled by the outlet passageways must take this into account, and must thereby be rendered less sensitive in response to the fluid amplifier. Another problem with fluid amplifiers has been that when the on outlet channel encounters back-pressure of a certain level or when it encounters blockage, it may allow fluid to back up into chamber 19 and divert around leading edge 20 and into the off outlet passageway thus creating a very substantial false output signal.

The prior art has recognized these deficiencies and limitations in true fluid amplifier usage. US. Patent 3,053,- 276 issued Sept. 11, 1962 to K. E. Woodward describes these problems in some detail, and despite the acknowledged advantages of preserving a true fluid amplifier (that is, no mechanical moving parts) offers a solution to these problems involving usage of a divider blade which prevents fluid back-up and false signals in the off passageway. While such a mechanical expedient may be useful in certain circumstances, the felt need for a fluid principle solution to the problem, thus preserving true fluid amplifier principles, has existed until the present invention.

The present invention utilizes a novel interplay between the outlet passageways, for example 17 and 18, outside the fluid amplifier itself, to prevent fluid back-up and to prevent false signals in the off outlet and to attain other advantages as hereinafter pointed out, all of which greatly contribute to the performance of fluid amplifiers in an area which heretofore constituted one of their notorious deficiencies.

As is shown in FIGURE 1 fluid outlet passageways 17 and 18 respectively communicate with extension portions 17a and 18a which portions meet in a full intersection 21 whereupon they each respectively continue to 17b and 18b. The intersection forms a double Venturi tube, that is, fluid passing through either branch 17a-17b or branch 18a-18b causes a slight pressure drop in the other branch adjacent the vicinity of intersection 21. The eifect is attained whether or not the respective branches intersect at right angles, although the right angle intersection shown produces optimum results. The constricted outline shown at 22 in branch 18a-18b, and at 23 in branch 17a17b, is necessary to produce the Venturi effect, but an operable configuration is attained with intersecting branches having only slight constrictions in the area of the intersection 21. Thus the amount of constriction may be chosen to produce an appropriate Venturi effect pressure drop for the specific fluid amplifier operating characteristics.

The employment of intersecting branches as aforesaid is in full keeping with the operation of true fluid amplifiers in that no mechanical parts are involved and only fluid principles are employed. Moreover, the intersecting Venturi-effect branches completely solve the aboverecited prior art fluid amplifier problems involving switching of a locked on power stream due to fluid back-up, false signals in the o passageway, and the like. Thus the concept afforded by the present invention does not hybridize fluid amplifier principles with mechanical parts, and yet provides a complete solution to the recited prior art output problems of fluid amplifiers. However, the improvement device of the present invention also can of course be employed advantageously in fluid amplifiers already having mechanically movable parts, or fluid amplifiers not utilizing lock-in of the power stream to a stable state.

In operation the fluid amplifier embodiment of FIGURE 1 or FIGURE 2 is provided with a power stream in power jet passageway 11 by power fluid source 14. The power jet emanating from orifice 11a is subject to lateral diversion by either of fluid control passageways 12 and 13. Assuming for illustration that fluid control source 15 is activated so that passageway 12 in the FIGURE 1 fluid amplifier embodiment is charged with control fluid under pressure, the power jet will be diverted to wall 1912, where it will lock-n because of boundary layer considerations. Theoretically the entire power jet flow will exit thereafter out of fluid outlet passageway 18 as the mainstream, with no fluid exiting out fluid outlet passageway 17. Actually however, a certain small portion of the mainstream will (because of turbulence or other reasons) find its way out fluid outlet passageway 17. In the fluid amplifier embodiment of FIGURE 2, control fluid flow out this same fluid control passageway 12 causes the power jet to lockonto wall 19a rather than wall 19b as in the FIGURE 1 fluid amplifier. The mainstream thus flows out fluid outlet passageway 17 in response to a signal in control passageway 12, just the opposite of the fluid amplifier of FIGURE 1. The derivative or unintended flow thus goes out outlet passageway 18, again just the opposite. The principle however is the same: the intended outlet passageway gets the mainstream fluid signal, while the other outlet passageway gets an undesirable derivative flow.

The remainder of this description of the operation of the fluid amplifiers of FIGURES 1 and 2 will trace the effects in that of FIGURE 1 only, since those in FIGURE 2 are the same in reversed passageways. In the prior art, the outlet passageways 17, 18 proceeded directly to their user destinations without any intersection therebetween. The false output flow existing in an unintended outlet passageway during the time the mainstream exits from the other outlet passageway has required that the user devices controlled by the outlet passageways be less sensitive, so as to accommodate this spurious and false signal. Also, since the false signal is proportional to the mainstream flow, a compromise had to be struck in design between the power rating(flow-rate) of the amplifier, and the amount of false output that could be tolerated. These and other disadvantages already described are eliminated by the present invention.

When the intersecting outlet passageways are employed as shown in FIGURE 1, and to continue the illustration of mainstream flow out of outlet passageway 18 in FIGURE 1, any false fluid flow signal travelling along outlet passageway 17 is drawn into region 23 by Venturi-effect pressure drop, and is entrained into the mainstream flow from 18:: to 18b, thus exiting with the mainstream at 181) instead of exiting as a false output signal at 17b. As will be apparent from an examination of FIGURE 1, when the fluid amplifier has its state changed so that the mainstream flows out outlet passageway 17, and hence across branch 17a-17b of intersection 21, any false signal in branch Isa-18b will be drawn in at 22 and entrained with the mainstream so as to flow out the outlet 17b with the mainstream instead of out of outlet 18b as a false signal.

Additionally, if for example the mainstream flow out either outlet, for example outlet 18b, is subject to overload and thus backed up, the mainstream may in prior art fluid amplifiers pile-up in chamber 19 causing flow out outlet passageway 17, which flow can lock the power jet onto wall 19a to passageway 17 without a signal from the appropriate control fluid passageway. The principal disadvantage in such prior art operation is not the false mainstream output thus immediately produced in outlet passageway 17, but the fact that when lock-in occurs the false mainstream flow will persist after the back-up or overload or blockage of outlet passageway 18 is relieved.

In the present invention on the other hand, when overload occurs in say outlet 18b carrying the mainstream, the overload even if it goes all the way to blockage, causes lb'ack-up only as far as intersection 21, whereupon the back-up portion of the mainstream will be diverted out outlet 17b. No back-up to chamber 19 occurs, and hence no mainstream flow in outlet passageway 17. Thus, when the back-up is relieved, the flow out outlet 17b stops and that flow is added back to whatever portion of the mainstream was flowing out outlet 18b all during back-up. It will be realized by those skilled in the art that this action constitutes a non-destructive readout. That is, unlike prior-art fluid amplifiers, back-up overloading of one outlet passageway cannot cause change of state of the amplifier. The read-out on say outlet 18b, no matter how much back-pressure it develops, cannot falsely change the state of the amplifier to 21 17b output. The output that does appear at 17b is not a change ,of state, since it disappears as soon as the back-up pressure is relieved. In effect the intersecting branches 17a- 17b, 18a-18b give the fluid amplifier a memory of its state during outlet overload conditions.

Moreover, in normal non-back-up operation, when for example a mainstream flow is carried by branch 18a-18b, a slight negative pressure is created at outlet 17b due to the Venturi effect at 21. It will be realized by those skilled in the art that this negative pressure at 1717 when 18b is the on outlet, makes the action of the on-ofi? switch formed by 1711 and 1817 more positive. That is, more contrast between the two conditions is provided. In the prior art, contrast was actually reduced by the false flow in the off outlet, in addition to the other deleterious aspects thereof. The negative pressure at the off outlet affords even greater design advantages than would occur if the off outlet were simply at zero gauge pressure and zero flow, as had been sought by the art.

In FIGURES 3 .and 4 is shown another form of the invention. The fluid amplifier shown in FIGURE 3 has the same type fluid controls shown in FIGURE 1, except that chamber 19 is divided into three outlet passageways 17, 18, and 25. Controlling the power jet emanating from orifice 11a are control fluid passageways 12 and 13. Other arrangements of control passageways may be employed, but the only essential for present purposes is to illustrate that three (and more) outlet passageway fluid amplifiers are known. The power jet is diverted out any one of the three or more outlet passageways by proper working of one or a combination of the control passageways. The principles are the same as have been already described, and so are the problems, including false derivative signals and fluid back-up. The triple intersection 21 of FIGURES 3 and 4 operates on the same principles as already described. Thus assuming a mainstream flow in branch 1711-1712, any false and derivative flow in branches 1812-181) and 25a-25b, is drawn into the mainstream and exits with the mainstream at 17b instead of falsely at 18b and 25b. Back-up is prevented by the same mechanism as already described, and nondestructive read-out occurs. The same effect of course inheres no matter which branch carries the mainstream. While it is necessary that the three branches intersect, it is not necessary that the three branches have: a mutually orthogonal intersection as shown, although that is advantageous.

There are additional advantages to employing intersecting outlet passageways as taught by the present invention. For example, if the tripartite intersection of FIGURE 4 is connected to a two outlet passageway fluid amplifier such as shown in FIGURE 1, an AND gate operating on fluid principles alone is available if desired, yet the usual advantageous operation of the ordinary single intersection fluid amplifier of FIGURE 1 is preserved. The operation thereof is as follows. Branch 17a-17b and branch 1811-1812 of FIGURE 4 are connected in the amplifier of FIGURE 1 in the manner indicated therein. Branch 25a-25b is not connected to the fluid amplifier, but is connected to an independent fluid source. This fluid source (not shown) should be capable of delivering a flow through branch 25a-25b appreciably greater than the mainstream flow in branch 17a17b or 18a-18b. This can involve greater diameter in branch 25a-25b, or greater fluid velocity. In any event, when fluid flow exists in branch 2501-251) under these circumstances, the flow in either of branches 17a-17b and 18a-18b is entrained thereinto, and exits at 251). The intersection 21 thus may be employed to use fluid flow in branch Z5a-25b to control Whether or not an output signal in lines 17 or 18 will appear at outputs 17b or 18b. In addition of course the interaction of branches 1711-17 b and 18a-18b remains, so that the false output in the unintended branch cannot occur.

Thus it can be seen that the intersecting branches of the present invention have general utility in controlling fluid flow representative of signals, and that the application to fluid amplifiers is but one highly advantageous and important use for such devices.

While the invention has been decribed with reference to certain physical embodiments thereof, the concept itself is not to be limited thereto. Variations in form and details may be made without departing from the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a fluid amplifier element having a plurality of fluid-flow outlet passageways, any one of which may have a mainstream of fluid-flow diverted therethrough, a device for preventing fluid back-up of said mainstream and for preventing under conditions of no-back-up the existence of spurious and false fluid-flow in any of said outlet passageways other than said mainstream carrying one, comprising a passageway extension associated with each of said outlet passageways, each of said passageway extensions crossing one another at a common point intermediate their lengths to thereby form a common intersection, and each of said passageway extensions having a constriction formed therein at said intersection to form a venturi in each of the extensions at the intersection whereby substantially all of said mainstream flows out one of said extensions and none of said mainstream flows out the other of said extensions.

2. A fluid amplifier substantially as described in claim 1 wherein the extensions are arranged to form essentially an orthogonal intersection.

3. A fluid amplifier substantially as described in claim 1 wherein the number of outlet passageways equals 2.

4. A fluid amplifier substantially as described in claim 1 wherein the number of outlet passageways is greater than 2.

References Cited UNITED STATES PATENTS 3,135,291 6/1964 Kepler 137-608 3,143,856 8/1964 Haus'mann 13781.5 3,177,888 4/1965 Moore 13781.5 3,181,545 5/1965 Murphy 13781.5 3,208,462 9/1965 FOX 137-8l.5 3,235,959 3/1966 Bowles 137-81.5 3,240,221 3/1966 Pan 137-815 M. CARY NELSON, Primary Examiner.

W. CLINE, Assistant Examiner.

Claims (1)

1. IN A FLUID AMPLIFIER ELEMENT HAVING A PLURALITY OF FLUID-FLOW OUTLET PASSAGEWAYS, ANY ONE OF WHICH MAY HAVE A MAINSTREAM OF FLUID-FLOW DIVERTED THERETHROUGH, A DEVICE FOR PREVENTING FLUID BACK-UP OF SAID MAINSTREAM AND FOR PREVENTING UNDER CONDITIONS OF NO-BACK-UP THE EXISTENCE OF SPURIOUS AND FALSE FLUID-FLOW IN ANY OF SAID OUTLET PASSAGEWAYS OTHER THAN SAID MAINSTREAM CARRYING ONE, COMPRISING A PASSAGEWAY EXTENSION ASSOCIATED WITH EACH OF SAID OUTLET PASSAGEWAYS, EACH OF SAID PASSAGEWAY EXTENSIONS CROSSING ONE ANOTHER AT A COMMON POINT INTERMEDIATE THEIR LENGTHS TO THEREBY FORM A COMMON INTERSECTION, AND EACH OF SAID PASSAGEWAY EXTENSIONS HAVING A CONSTRUCTION FORMED THEREIN AT SAID INTERSECTION TO FORM A VENTURI IN EACH OF THE EXTENSIONS AT THE INTERSECTION WHEREBY SUBSTANTIALLY ALL OF SAID MAINSTREAM FLOWS OUT ONE OF SAID EXTENSIONS AND NONE OF SAID MAINSTREAM FLOWS OUT THE OTHER OF SAID EXTENSIONS.

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