US3180346A

US3180346A - Fluid flow control stage

Info

Publication number: US3180346A
Application number: US249683A
Authority: US
Inventors: Biliy E Duff
Original assignee: Midwestern Instruments Inc
Current assignee: Midwestern Instruments Inc
Priority date: 1963-01-07
Filing date: 1963-01-07
Publication date: 1965-04-27
Anticipated expiration: 1982-04-27

Description

April 27, 1965 B. DUFF FLUID FLOW CONTROL STAGE Filed Jan. 7, 9 1963 United States Patent Ofitice 3,180,346 FLUID FLOW CQN'IRQL STAGE Billy E. Duh, Tulsa, Okla assignor to Midwestern Instrumerits, lira, Tulsa,0lda., a corporation of Oklahoma Filed Jan. 7, 1963, Ser. No. 249,633

12 Claims. (Cl. 137--.81.5)

This invention relates generally to fluid flow control and, more specifically, to means for controlling the path of travel of a primary fluid stream through the use of secondary fluid streams directed against the primary stream to deflect the latter.

The primary object of the present invention is to provide means for varying the path of travel of a primary fiuid stream by directing secondary fluid streams at the primary stream, variation in said path of travel being accomplished by controlling the relative distances from the primary stream of the discharge orifices emitting the secondary streams.

Another object of this invention is to provide means for varying the flow of a primary fluid stream into the inlets of a receiver coupled with pneumatic or hydraulic mechanism, such flow variation being accomplished by shifting the discharge orifices of secondary fluid streams directed at the primary stream in directions to move the discharge orifices out of equidistant relationship with the primary stream.

' It is still another object of this invention to provide a fluid flow control stage utilizing a primary fluid stream and a pair of secondary fluid streams directed against opposite sides of the primary stream, the power of the primary stream being relatively high as compared with the secondary streams, displacement of the conduit means directing the secondary stream-s efiecting deflection of the rimary stream.

it is yet another object of this invention to provide a fluid amplifier capable of deflecting a higher powered fluid stream by directing a pair of lower powered fluid streams thereagainst, slight displacement of the discharge orifices emitting the lower powered streams causing deflecting of the higher powered stream.

Other objects will become apparent as the detailed description proceeds.

In tr e drawing:

FIGURE 1 is a cross-sectional view showing a simplified embodiment of the present invention incorporated into a hydraulic servovalve; and

FIG. 2 is a diagrammatic representation showing the operation of the present invention.

Referring to FIG. 1, the control stage of the present invention is shown utilized as a pilot stage in a two-stage hydraulic servovalve. A block serves as a housing for the pilot stage and power stage components. Mounted on block Ill is an enclosure l2 which is maintained in fluid-tight engagement with block lb by a pair of O-rings 14 and 16. Within enclosure 12 is a torque motor 18 to be described hereinafter.

A conduit Zll is shown coupled with'torque motor 13, the arrow indicating that conduit Zll carries fluid in the direction shown and through motor 18 to a pair of C- snaped branches 22 and 24. Branches 22 and 24 form nozzles having outlets or orifices in the terminal ends thereoffor discharging fluid streams who referred to in this specification as secondary fluid streams.

A passage in the block 10 receives a tube 26 which transmits fluid in the direction illustrated by the arrow. Tube terminates within a chamber 28 containing the nozzles 22 and 24. A downwardly directed orifice in the terminal end of tube 26 discharges fluid therefrom in a direction to traverse the secondary streams emitted from nozzle 22 and 2 The stream emitted from tube 26 will be hereinafter referred to in this specification as the primary fluid stream, such stream generally being of a higher power than the secondary streams previously described.

Projecting upwardly from the base of chamber ZS is a receiver having a pair of juxtaposed inlets or orifices 3'3 and 32. At the base of chamber 2% and below the receiver inlets 3 and 32 is a channel 34 which serves tov exhaust excess fluid from chamber 28 during operation of the apparatus. Inlet MB is in communicationwith cylinder 36 by way of passageway 38, and receiver inlet 32 is in communication with cylinder as by way of passagcway i l. Cylinder 36 is formed by boring completely through block it and then inserting plugs 42 at each end thereof. G-rings 44 in plugs 42 assure that the cylinder 36 is maintained sealed. 7 I

A spool generally designated 46 and having heads 43, till, 52 and 5 rigidly interconnected by rods 56, 53 and 69 is disposed in cylinder '36 as shown. An exhaust port 62 is normally disposed in communication with the porion of cylinder 36 between heads diiand 50. Exhaust port 64 is normally communicated with the portion of cylinder 36 between heads 52 and 54. Pressure port do is normally communicated with the portion of cylinder 36 between heads 5%) and 52. Load ports 63 and 78 are normally blocked and thereby placed out of fluid con munication with cylinder as by heads St? and 52, respectively, the metering edges of heads 5% and 52 overlapping the sides of ports as and 7t suflicient to block the passage of fluid. Pressure ort 66 is connected with a fluid source (not shown), exhaust ports 62 and 64- being connected with the fluid reutrn of such source. Load ports 68 and "iii are coupled with the hydraulic device under control.

Thus, it may beappreciated that a power stage of a hydraulic servovalve is formed by cylinder 56, spool 46 Orifices 23 and 25 in nozzles 22 and 24, respectively,

direct secondary fiuid streams toward each other and against the sides of primary stream 72. Arrows 74 and '76 represent the secondary fluid streams. The structure appearing in solid lines in FIG. 2 illustrates the positions oi the nozzles 22 and 24 relative to theprirnary fluid.

stream when no deflection of the primary stream is de sired. At this point, the orifices 23 and 25 are equidistant from respective sides of the primary fluid stream. However, upon movement of the nozzles .to the positions shown by the dashed lines upon rightward movement of the nozzles, orifice 23 is placed in closer spaced relationship to the primary stream than orifice 25. Deflection of the primary stream to the right as viewed in FIG. 2 thus occurs and a greater quantity of the flowing fluid in stream 72 is directed at inlet 32 than at inlet 36 An unbalance of fluid flow, and hence pressure into inlets 3t and 32, thus occurs.

The power of the secondary streams represented in FIG. 2 by arrows 7d and 76 may be small relative to the power of the primer stream 72. The secondary streams serve as control streams to vary the path of travel of the higher powered primary stream. This enables amplification because low flow is utilized to deflect high flow. In operation, care must be taken to maintain the power of the secondary streams at a sufficiently low level to prevent them from destroying the integrity of the primary stream. In other words, a spraying effect at the point in the primary stream where it joins with the secondary streams is not desired.

For optimum results the nozzles discharging the second ary streams should be opposed as shown in the figures, and the secondary streams discharged substantially orthogonally of the primary stream. Variations from this configuration may be made of course, depending on the particular control characteristics desired.

Reference is now made to FIG. 1 where operation of the present invention will be described in terms of practical utilization of the results obtainable therefrom. The torque motor 18 is utilized to etfect the desired displacement of the nozzles 22 and 24 to effect deflection of the primary stream. Motor 18 is an actuating device similar to conventional types familiar to those skilled in the art, and is utilized to effect small displacements of the nozzles 22 and 24- to the left and to the right as viewed in FIG. 1.

'totor 18 utilizes a pair of pole pieces 78 and 8t) and a pair of coils 82 and 84 to control the displacement of the nozzles responsive to electrical signals. Pole piece '78 and coil 82 form an electromagnet which, when energized, etfects movement of the nozzles to the left as viewed in the figure. Pole piece 80 and coil 84, when energized, effect movement of the nozzles to the right.

The essential internal structure of motor 18 for effecting the control purposes set forth above, includes an armature 86, permanent magnets 88 and 9t), a resilient tubular member $2, and a tubular stem 94 forming a part of conduit 28. A collar 96 integral with one end of tubular member 92 secures the same to an opening in frame member 98 of motor 18. Tubular member 92, armature 86 and an enlarged portion 109 of stern 94 are rigidly interconnected at the juncture with the armature. Since member 92 is resilient, the armature may be attracted to either of the electromagnets when one of the electromagnets is energized. The armature is restored to its normal position as shown upon de-energization of the electromagnets due to the restoring force of the resilient member 92. The restoring force is assisted by

permanent magnets

88 and 90 which impose equal and opposite forces upon the armature at all times.

The tubular stem 94 has a smaller outside diameter than the inside diameter of member 92 until the enlarged portion 160 is reached, at which time the stem 94, member 92 and armature 86 are rigidly joined together as described above. This enables stem 94 to swing to the left and right as viewed in FIG. 1 when the tubular member 2 is deformed during attraction of the armature to one of the electromagnets. Actually therefore, the nozzles 22 and 24 integral with the end of stem 9d extending into chamber 28 move in an arcuate path when the electromagnets of the torque motor are energized. This displacement is so small however, that for all practical purposes the movement of the nozzle orifices toward and away from the primary fluid stream can be considered to be along linear paths of travel. It may be appreciated that the enlargement 1% is integral with conduit and thus fluid for the primary fluid stream is allowed to pass from the source thereof to the nozzle orifices.

In the operation of the control stage shown in FIG. 1, conduit 2% and tube 26 are connected to appropriate fluid sources (not shown). In practical applications, a single fluid source may be utilized for both the primary and secondary fluid streams. It may be convenient to utilize a portion of the main hydraulic fluid supply for this purpose, the fluid utilized in the control stage often being only a very small percentage of that available from the hydraulic supply. As the primary fluid stream impinges on receiver inlets 3t) and 32, as illustrated by the downwardly directed, vertical arrow in chamber 28, the fluid passes through

passageways

38 and 40 to the respective chambers formed at the ends of cylinder 36 between head 48 and the corresponding plug and between head 54- and its corresponding plug. When the orifices of the nozzles 22 and 24 are equidistant from the primary stream, fluid flow into orifices and 32 will be equal and no pressure differential between the chambers at the ends of cylinder 36 will exist. However, it may be appreciated that leftward or rightward displacement of the nozzles will effect a deflection of the primary fluid stream as described above, and a pressure differential will then exist. When this occurs, the spool 4-6 will move to equalize the pressure differential.

For example, if it is desired to communicate pressure port 66 with load port 68, the nozzles would be displaced rightwardly to increase the pressure in passageway 49 and the chamber formed between head 54 and the adjacent plug 42. Leftward movement of spool 46 is thus effected and load port 68 is placed in communication with pressure port 66 as the righthand metering edge of head 50 advances to the left. Simultaneously, the right-hand metering edge of head 52 also advances leftwardly placing load port 70 and exhaust port 64 in communication thereby allowing the load to exhaust. It may be appreciated that movement of spool 46 to the right communicates

ports

62 and 68 for exhaust and

ports

66 and 78 to drive the load.

Since passageways 38 and 4t) and their associated chambers will fill with fluid from the primary and secondary streams, the exhaust channel 34- allows the excess fluid in chamber 28 to drain otf before the receiver inlets 3t) and 32 can fall below the fluid level in chamber 28. Thus, the inlets 3t) and 32 are never allowed to become immersed in the fluid from the primary and secondary streams. It is inherent in the operation of the apparatus, of course, that during motion of the spool the restricted chamber will discharge fluid from the corresponding receiver inlet while the other inlet is receiving fluid from the primary and secondary streams. Any turbulence created at the

receiver inlets

30 and 32 during this action, however, has been found to not interfere with the proper operation of the fluid control stage.

Although in the foregoing description the practical utilization of the present invention has been illustrated by its incorporation into a hydraulic servovalve, it should be understood that the teachings of this invention may be applied equally as well to pneumatic mechanisms. The primary and secondary fluid streams may be gaseous as well as liquid. The principle of operation of the control stage remains the same in either instance.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a control:

means for directing a primary fluid stream along a predetermined path of travel;

conduit means provided with a pair of outlets disposed to discharge secondary fluid streams in opposite directions against said primary stream transversely of the latter; and

means for shifting the outlets toward and away from said primary stream to deflect the primary stream laterally of said path of travel.

2. The invention of claim 1, said outlets being normally equidistant from said primary stream, said directions being substantially orthogonal of said predetermined path of travel.

3. In a control:

conduit means provided with a pair of opposed outlets disposed to discharge secondary fluid streams in opposite directions toward each other against said primary stream transversely of the latter; and

4. In a control:

conduit means for continuously supplying a secondary fluid and provided with a pair of outlets disposed to discharge streams of said secondary fluid in oppo- Site directions against said primary stream transversely of the latter; and

means operably coupled with said conduit means for shifting the latter to move the outlets toward and away from said primary stream, whereby to deflect the primary stream laterally of said path of travel.

5. In a control:

structure having a pair of juxtaposed inlets;

means for directing a primary fluid stream at said inlets along a normal path 'of travel permitting predeter mined portions of said primary stream to impinge on said inlets;

conduit means provided with a pair of outlets disposed to discharge secondary fluid streams in opposite directions against said primary stream between said directing means and said structure transversely of the primary stream; and 7 means for varying the portions of said primary stream impinging on said inlets including apparatus operably coupled with said conduit means for shifting the outlets toward and away from said primary stream to deflect the primary stream laterally of said path of travel.

6. In a control:

structure having a pair of juxtaposed inlets;

means for directing a primary fluid stream along a normal path of travel in substantial alignment with said inlets for flow into the latter;

conduit means provided with a pair of outlets disposed to discharge secondary fluid streams in opposite directions against said primary stream between said directing means and said structure transversely of the primary stream; and

means for varying the flow of primary fluid into the inlets including apparatus for shifting the outlets toward and away from said primary stream to deflect the primary stream laterally of said path of travel and out of direct alignment with one of said inlets.

7. In a control:

structure having a pair of juxtaposed inlets;

a conduit for continuously supplying a secondary fluid and provided with a pair of nozzles disposed on opposite sides of said primary stream between said directing means and said structure, the nozzles having orifices for discharging streams of said secondary fluid against said primary stream transversely of the latter; and

means for varying the flow of primary fluid into the inlets including apparatus operably coupled with the nozzles for shifting the same toward and away from said primary stream to deflect the primary stream laterally of said path of travel and out of direct alignment with one of said inlets.

8. The invention of claim 7, the nozzles being at one end or" the conduit.v

9. The invention of claim 7, the nozzles being opposed,

the orifices discharging said secondary streams toward each other.

10. The invention of claim 7, the orifices being normally equidistant from said primary stream.

11. In a control:

Structure having a pair of juxtaposed inlets;

a conduit provided with a pair of opposed nozzles at one end thereof disposed on opposite sides of said primary stream between said directing means and said structure, the nozzles having orifices normally equidistant from the primary stream for discharging secondary fluid streams toward each other against said primary stream and substantially orthogonally thereof; and

means for varying the flow of primary fluid into the inlets including apparatus operably coupled with the nozzles for shifting the same toward and away from said primary stream to deflect the primary stream laterally of said path of travel and out of direct alignment With one of. said inlets.

12. In a control:

structure having a pair of juxtaposed inlets;

a conduit terminating at one end thereof in a pair of (Z-shaped branches each provided with an outlet, the outlets being in opposed relationship for directing secondary fluid streams toward each other, the primary stream traversing the secondary streams between said outlets; and

means for varying the flow of primary fluid into the inlets including apparatus operably coupled with the conduit for shifting the outlets toward and away from said primary stream to deflect the primary stream laterally of said path of travel and out of direct alignment with one of said inlets.

References Cited by the Examiner UNITED STATES PATENTS 3,001,698 9/61 Warren 23561 3,016,063 1/62 Hausmann 137597 FOREIGN PATENTS 1,083,607 6/60 Germany.

LAVERNE D. GEIGER, Primary Examiner.

Claims

1. IN A CONTROL: MEANS FOR DIRECTING A PRIMARY FLUID STREAM ALONG A PREDETERMINED PATH OF TRAVEL; CONDUIT MEANS PROVIDED WITH A PAIR OF OUTLETS DISPOSED TO DISCHARGE SECONDARY FLUID STEAM IN OPPOSITE DIRECTIONS AGAINST SAID PRIMARY STREAM TRANSVERSELY OF THE LATTER; AND MEANS FOR SHIFTING THE OUTLETS TOWARD AND AWAY FROM SAID PRIMARY STREAM TO DEFLECT THE PRIMARY STREAM LATERALLY OF SAID PATH OF TRAVEL.