US3552413A

US3552413A - Feedback divider for fluid amplifier

Info

Publication number: US3552413A
Authority: US
Inventors: Raymond W Warren; Ralph G Barclay; John Gerald Moorhead
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1962-09-10
Filing date: 1964-06-12
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05

Abstract

This invention relates to pure fluid amplifiers having dynamic feedback dividers for providing a feedback which contributes assistance to the boundary layer lock-on phenomena.

Description

. .[21] ApplQNo.

United States Patent Raymond W. Warren McLean, Va.;

Ralph .G. Barclay, John Gerald Moorhead,

Silver Spring, Md.

June 12, 1964 said Warren assignor to the United States of America as represented by the Secretary of the Army A division of Ser. No. 222,748, Sept. 10,

1962, now Patent No. 3,397 .713.

[72] Inventors [22] Filed [45] Patented [73] Assignee [54] FEEDBACK DIVIDER FOR FLUID AMPLIFIER -4 Claims, 1 Drawing Fig.

52 us; Cl. 137/815 [51] Int. Cl Fl5c 1/08 [50] Field ofSearch 137/815 [56] References Cited UNITED STATES PATENTS 1,658,797 2/1928 Charrette et al.

3,181,546 5/1965 Boothe 137/815 3,225,780 12/1965 Warren et a1. 137/81.5 3,192,938 7/1965 Bauer l37/81.5 3,244,370 4/1966 Colston 137/81.5X

Primary Ekaminer-SamuelScott Attorneys Harry M. Saragovitz, Edward J Kelly, Herbert Bet] and J. DqEdgerton ABSTRACT: This invention relates to pure fluid amplifiers having dynamic feedback dividers for providing a feedback which contributes assistance to the boundary layer lock-on phenomena.

' vider'for Fluid Amplifiers.

The invention described herein may be manufactured and I used by or for the Government of the United States of America for Governmental purposes without the payment to me of any royalties thereon. j p 3 This invention relates to fluid amplifiers and more particularly,to dynamicfeedhack dividers in fluid amplifiers.

1968, entitled'Feedback Di- In previous fluid amplifiers, the dividers which separate the 2 output channels were substantially wedge shaped with the pointed edge of the wedge aligned with the power nozzle in such a mar ner that the divider would separate the interaction region into two output channels; Wall of the flow from the power stream could not be contained in'one output channel, the divider would, separate. the power stream into a majority flow and a minority flow into the output channels. The favored channel was the channel which had the majority of the power stream' flow. Favoring of one output channel over the other was a function of the 'symmetryof the amplifier elements, the smoothness of the surfaces exposed to the power stream flow the divergence of the output channels', the amount of control provided directly on-the stream, boundary layer effects, loading of the outputs, and the like.2 0nce favored, the power stream would remain in the favoredioutput channel until a control signal was provided to switch it tothe other channel. This control signal couldioriginate externally of the amplifier,

. could bea portion of the power stream. feedback to the inbility that wouldprevent the stream from remaining in a favored channel untilswitching to the other channel is desired. One of these causes is encountered when the amplifier is connected to a-load. The resistance in the system could be suchthatthe output'channel would no longer carry all of y the power stream as it w'o'uld'in' an unloaded condition. Under these circumstances, the return of the-excess power stream A further object of this invention is to provide a divider which eliminates the need of counterflow in the output channel not favored by the power stream in a fluid amplifier so as to enable the use of the fluid amplifier in outer space or other low-pressure environments.

A still further object of this invention is to provide a divider in a fluid amplifier which provides a momentum in a feedback flow which serves as a control signal.

The FlG. shows one embodiment of this invention.

Briefly, the-purposes of thisinvention are accomplished by the provision of a divider in a fluid amplifier which feeds back a part of the power stream in one receiver to reinforce the forces diverting the power stream into said one receiver. Feedback is against a blunt or curved end of the divider to provide a pressure seal over the entrance to the not favored output channel and also to reinforce the diverting forces on the power stream which direct it into the favored channel. A vortex is generated which further enhances the reinforcement and provides a dynamic characteristic.

The bistable amplifier shown in FIG. 1 has power jet nozzle,

opposed control nozzles, and a pair of

output receiver channels

42 and 43. Separating the

receivers

42 and 43 is a divider 'with a concave curved surface 41. Allof the downstream material of the divider has been removed to present the surface 42 as the curved leading edge of the divider between

output receivers

42 and 43. Between the curved surface 41 and the interaction chamber 47, there isno divider structure. The

- curved structure4l is concave when viewed from the power down the favored channel against gthe flow of the power I stream can cause perturbations and turbulences that wouldpromote instability; Since all the'fluid does not get out into the load, some of the fluid leaks around the divider and-out through the other channel. Oscillations as well as other instabilities may result-Further, the direction of all of the power stream into a favored output channel and maintaining it there.

could require an excessive amount of control signal, and could require that the control signal be applied for an excessive amount of time.

- Accordingly, this invention is'directed to improvements in fluidarnplifier dividers which provide:- increased stability in a fluid amplifier; reliability of memory functions; an assist to'the boundary layer lock-on phenomena; the reduction or elimination of counter flow through theunfavored output channel as, well as the need. therefor: momentum in a feedback ,flow

which serves as a locking control signal; feedback signals which have vector properties, and feedback signals which operate in the manner ofa servo feedback signal.

It is, therefore, an object of this invention-to provide an improved dividerin a fluid-operated device.

. L A further object of this, invention is to provide a divider which contributes to the stability ofa fluid amplifier.

A still further object of this invention is to provide a divider which enables reliability of memory functions in a fluid amplinozzle. The interaction chamber47 is'bounded by the divider tional in the art, the control nozzles control which receiver channel wall the power jet latches on to.

In operation, the divider curved edge 41 .forms a vortex and directs the feedback flow down alongthe unfavored receiver receiver sidewall, and in the vicinity of the sidewall, turns to travel near the sidewall in a direction away from the interaction chamber 47 as shown by flow'line 44. A majority of the feedback flow is directed into the interaction chamber 47 as shown by flow line 44. A majority of the feedback flow is directed into the interaction chamber. where a vortex 45 is formed by curved flow of the feedback fluid to provide momentum to the power stream in receiver 42 to further lock the power stream therein. The remainder of the flow distributes through the remainder of the interaction chamber 47 in the circular paths indicated by the remaining arrows 46.

The flow line 44 indicates a pressurearea which is a barrier sufficient to maintain power stream integrity even if the pressure available exterior to the fluid amplifier is very low. This permits the amplifier to operate in outer space. The vortex 45 and the lock-on assist vectors 46 would be maintained in the absence of a counterpressure down the unfavored receiver 43.

The fluid amplifier in this disclosure is the wall effect amplifier The basic bistability comes about because the stream entrains away fluid and produces a low-pressure separation bubble on the wall. This is indicated in the drawing by the exposure of the short bottom end of the sidewall of the favored receiver to which the power stream is shown not attached. The entrainment and the bubble provide a low-pressure region V which allows the higher pressure on the opposite side of the power stream to hold the stream against the favored sidewall. The effectiveness of the holding of the stream against the sidewall depends on the pressure differential on the two sides of the stream. The feedback divider splits off part of the stream and directs it so as to increase the pushing pressure lock-on. ln the embodiment shown, should the stream move away from the bistable position, more of the stream is split off and the pushing pressure is increased forcing the stream back into its bistable position. The action of this restoring pressure that is generated is similar to the action ofa servoloop.

Fluid amplifiers of the type of which this invention is an improvement are more adequately disclosed in the copending application entitled Fluid Amplifier Employing Boundary Layer Effect, Ser. No. 58,188, filed Oct. 19, 1960 and now US. Pat. No. 3,396,6l9 revised Aug. 13, 1968. by Raymond W. Warren et al. Mr. Warren is one of the inventors of this application.

So, it is seen that we have provided an improved divider in a fluid amplifier. The divider improvements of this disclosure contribute to stability and enable reliability of memory functions in a fluid amplifier. The counterflow in the not-favored output channel is reduced or eliminated and operation in outer space is provided. The lock-on phenomenon is reinforced by the feedback flow and by the momentum of such flow. The feedback flow has vector properties. The counterflow around the pointed edge of the divider has been eliminated and the wandering of the power stream has been used to provide a pressure proportional to such wandering to reinforce the power stream in a stable position in the manner of a servoloop.

It will be apparentthat the embodiment shown is only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

The divider 41 can be concave as shown, blunted as said above, squared off, or in any shape that will provide the flow pattern needed to reinforce the lock-on pressure differential and provide stabiltiy. An example of such a flow pattern is shown by arrows 46 and vortex 45. Dividers shaped like a flat open box, with the open end directed toward the power stream, will provide a flow pattern that is equivalent to that provided by a concave divider.

We claim:

1. In a fluid amplifier:

a. a fluid power source for producing a fluid stream;

b. A pair of divergent receiver means;

c. means for directing said power stream toward said receiver means;

d. divider means for separating said pairof receiver means;

e. said divider means being a solid element having a pair of divergent sides which form the inner side'sfof said pair of receiver means; and having'a thirdis'ide connecting the closer ends of the divergent si s, and I, I I

f. said third side providing a feedbaclg'flowltoreinforce the continuance of power was iii one of said receiver means. i i

a. a fluid power source for producingzi uid stre'a'm;

b. a pair of divergent receiver meansi i c. means for directing said power stream toward said receiver means; I

d. divider means for separating said pair of receiver means;

e. said divider means being a solid element having a pair or receiver means, and having a third side connecting th closer ends of the divergent sides; and i f. said third side being arcuate in shape.

a. a fluid power source for producing a fluid stream;

b. a pair of divergent receiver means;

c. means for directing said power stream toward said receiver means;

d. divider means for separating said pair of receiver means;

ersaid divider means being a solid element having a pair of divergent sides which form the inner sides of said pair of receiver means, andhaving a third side connecting the closer ends ofthe divergent sides and f. said third side being concave in shape with respect to said power source. v

4. A fluid device comprising an inlet for supplying power fluid, a pair of outlets, a pair of control inlets for.directing said power fluid to a selected outlet, and a vortex chamber all leading from a common mixing chamber,lsaid vortex chamber being disposed intermediate said outlets and in alignment with said inlet to receive power fluid therefrom, said vortex chamber being dimensioned to create a vortex movement of fluid therein with a portion of said fluid being directed to said selected outlet to maintain said fluid at said selected outlet after the application of fluid from said control inlets has terminated, said control inlets being disposed at substantially right angles with respect to said inlet and said vortex chamber, said outlets being angularly disposed away from said inlet-.on opposite sides of said vortex chamber and between said vortex chamber and said control inlets.

Claims

1. In a fluid amplifier: a. a fluid power source for producing a fluid stream; b. A pair of divergent receiver means; c. means for directing said power stream toward said receiver means; d. divider means for separatiNg said pair of receiver means; e. said divider means being a solid element having a pair of divergent sides which form the inner sides of said pair of receiver means; and having a third side connecting the closer ends of the divergent sides; and f. said third side providing a feedback flow to reinforce the continuance of power stream in one of said receiver means.

2. In a fluid amplifier: a. a fluid power source for producing a fluid stream; b. a pair of divergent receiver means; c. means for directing said power stream toward said receiver means; d. divider means for separating said pair of receiver means; e. said divider means being a solid element having a pair or receiver means, and having a third side connecting the closer ends of the divergent sides; and f. said third side being arcuate in shape.

3. In a fluid amplifier: a. a fluid power source for producing a fluid stream; b. a pair of divergent receiver means; c. means for directing said power stream toward said receiver means; d. divider means for separating said pair of receiver means; e. said divider means being a solid element having a pair of divergent sides which form the inner sides of said pair of receiver means, and having a third side connecting the closer ends of the divergent sides; and f. said third side being concave in shape with respect to said power source.

4. A fluid device comprising an inlet for supplying power fluid, a pair of outlets, a pair of control inlets for directing said power fluid to a selected outlet, and a vortex chamber all leading from a common mixing chamber, said vortex chamber being disposed intermediate said outlets and in alignment with said inlet to receive power fluid therefrom, said vortex chamber being dimensioned to create a vortex movement of fluid therein with a portion of said fluid being directed to said selected outlet to maintain said fluid at said selected outlet after the application of fluid from said control inlets has terminated, said control inlets being disposed at substantially right angles with respect to said inlet and said vortex chamber, said outlets being angularly disposed away from said inlet on opposite sides of said vortex chamber and between said vortex chamber and said control inlets.