US 3289687 A
Description (OCR text may contain errors)
Dec. 6, 1966 J. c. DUNAWAY 3,289,687
ACTUATOR FOR PURE FLUID AMPLIFIER Filed Feb. 13, 1964 J. C. Dunaway,
2 BY V I A M 7% Wu United States Patent 3,289,687 ACTUATOR FOR PURE FLUID AMPLIFIER J. C; Dunaway, Falltville, Ala., assignor to the United States of America as represented by the Secretary of the Army Filed Feb. 13, 1964, Ser. No. 344,788 3 Claims. (Cl. 137-815) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.
This invention relates to an actuator for use with pure fluid amplifiers and particularly to an electromechanical actuator for diverting the direction of a fluid power stream in fluid amplifiers by creating pressure differentials across the fluid power stream.
There are many devices disposed for switching, controlling, deflecting, separating or otherwise redirecting a fluid power stream so that it maybe utilized to perform a useful function. However, many of the devices have moving parts and require considerable force to open a duct once it is closed where high velocity of the stream is involved. Furthermore, most of these moving parts are positioned in the stream and the moving parts are, therefore, susceptible to corrosion and subsequent jammmg.
There are other known fluid amplifiers in which a control stream of fluid is used to impinge on the sides of the fluid power stream, at or near a 90 angle therewith and the momentum of the control flow will cause the power jet to deflect. However, these devices require separate sources from which the control stream must be obtained.
The present invention overcomes such noted difliculties by providing an actuator for diverting the stream by selectively venting portions of the fluid power stream to the atmosphere creating pressure differentials across the power jet for diverting and controlling the direction of flow of the power jet.
The actuator of the present invention provides a low power means to open and close the control ports of atmospheric controlled fluid amplifiers and thus create pressure differentials across the power jet to control the direction of flow thereof.
One advantage of the present invention is that the device utilizes a vacuum, created in one side of the fluid valve by the power jet itself, to assist in opening the control ports of the valve.
A further advantage of the apparatus of the present invention is that no pressurized control medium is required in environments which approach standard atmospheric.
It is, therefore, an object of the present invention to provide a device capable of directing a high velocity stream of fluid to a preselected one of a plurality of exit ports.
It is, therefore, an object of the present invention to provide a device for selectively directing a stream of fluid to one of a plurality of exit ports of a fluid amplifier.
It is a further object of the present invention to provide an actuator disposed for effecting proportional and onoff control of the power jet of a pure fluid amplifier by differential pressures created across the power jet responsive to flow of the power jet.
Other objects, features and advantages of the present invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
FIGURE 1 is a sectional plan view of a fluid amplifier including control ports through which the direction of flow of the power stream is controlled by use of the actuation of the present invention; and
FIGURE 2 is a sectional view along line 2-2 of FIG- URE 1 and illustrates the actuator of the present inven- 3,289,687 Patented Dec. 6, 1966 tion disposed for operation in the control ports of the fluid amplifier.
As shown in FIGURES 1 and 2 the fluid amplifier 10 includes a body 12 having a chamber or nozzle 14 disposed therein. The fluid amplifier includes a. passageway 15 disposed for connection to a source of fluid under pressure. Nozzle 14 includes an inlet 16 disposed in communication with passageway 15 and an exit section 18. At a distance W from the exit section 18 of the nozzle is a splitter 26. Splitter 20 is provided with a leading knife edge 22 mounted directly on the center line with the nozzle exit section 18. A pair of exit ports 24 and 26 are open to the atmosphere at one end 25 of body 12. Ports 24 and 26 join at the edge 22 of the splitter to form a chamber 27 which extends to join the nozzle exit section 18.
A pair of offset orifices 28 and 30 are disposed in communication with chamber 27, on opposite sides thereof.
Each of the orifices28 and 30 have respectively disposed in communication therewith a pair of apertures 32 and 34. A pair of closure members 36 and 38 are connected to an actuator 39 and are respectively movably mounted adjacentthe open, outer ends 40 and 41, respectively, of each of apertures 32 and 34. Actuator 39 is disposed to selectively close either of the openings 40 and 42 to the atmosphere.
It is to be understood that the fluid amplifier as disclosed herein is of the type disclosed in a patent applica tion filed February 13, 1964, by Kenneth C. Evans, Serial No. 344,791, for Pure Fluid Amplifier and Pure Fluid Amplifier Attitude Control System for Missiles. How ever, the fluid amplifier is illustrative of many fluid amplifiers in which the actuator of the present invention may be utilized.
The actuator 39 of the present invention provides a low power means to open and close the control ports of atmospheric controlled fluid amplifiers.
One advantage of the actuator is that the device utilizes a vacuum, created in one side of the fluid valve by the power jet itself, to assist in opening the control ports of the valve.
Actuator 39 is mounted on body 12 and includes a pair of solenoids 42 and 44, a flapper arm 46 pivotally mounted for reciprocal movement, and a pair of pistons 48 and 50, each respectively provided with connecting rods 52 and 54. The rods 52 and 54 are pivotally secured to opposite ends 56 and 58 of flapper 46.
In operation, the fluid is admitted through the entrance of the nozzle 14 at a predetermined pressure. With ports 24, 26 and apertures 32 and 34 open to the atmosphere and the nozzle pressurized, flow occurs through the nozzle and impinges on the knife edge 22 of splitter 20, which is directly on the center line of the stream projected by the nozzle. As the stream flows from the exit section 18 of the nozzle and past the orifices 28 and 30, particles of air are entrained, tending to lower the pressure in these orifices; however, since these orifices are vented to the atmosphere at the ends 40 and 41 thereof, the tendency for low pressure to exist in orifices 28 and 30 is alleviated and the power jet is divided into two streams of equal characteristics through ports 24 and 26.
To cause the power jet to move toward port 24 solenoid 44 is energized moving the end 58 of flapper 46 upward and the end 56 of flapper 46 downward so that closure member 36 engages opening 40 to close-off aperture 32 to the atmosphere. With the actuator in this position and a fluid flowing through the fluid amplifier a vacuum is created in orifices 28 and 32. Since port 41 is open, the pressure in aperture 34 is near ambient and a differential pressure exists across the flapper creating a force tending to hold the closure member 36 in engagement with opening 40. The result, then, is a pressure 3 diflerential acting across the power jet causing it to move to port 24.
To cause the power jet to move from port 24 to port 26 it is only necessary to change (reverse) the position of the flapper. This is done by removing power from solenoid 44 and applying it to solenoid 42. The flapper then pivots the end 56 upward to open aperture 32 to the atmosphere. End 58 of flapper 46 is then pivoted downward for engagement of closure member 38 with opening 41 to close port 34 to the atmosphere, thus creating a vacuum in port 34 and increasing the pressure in aperture 32 to create pressure differentials across the power stream to divert it to port 26.
In this position, a pressure differential is created across the flapper creating a force tending to hold closure member 38 in engagement with opening 41.
The greatest force existing between the solenoids and the flapper is exerted when the flapper and solenoid are in contact. As the distance between the solenoid and flapper increases the magnet pull is greatly decreased. The opposing force, created by the pressure differential across either of pistons 48 or 50 exists only when one of the openings 40 or 41 are closed to the atmosphere by the flapper.
The force on the flapper (created by vacuum) may be unbalanced by making pistons 48 and 50 larger in diameter than the openings 40 and 41. This causes the atmospheric pressure to be distributed across a larger area (the bottom of the piston) than is distributed across the smaller openings 40 and 41 of apertures 32 and 34. Thus, the pressure diflerential tends to force the flapper away from openings 40 and 41 selectively open ports 32 and 34 to the atmosphere. Thus the flapper can be moved from one position to its other position with a small amount of electrical power.
The valves and actuator of the present invention can be used for attitude control of a missile, or in thrust vector control of a missile as disclosed in the application filed by Kenneth C. Evans filed concurrently herewith.
It is to be understood that various modifications and variations may be readily apparent to those skilled in the art that is within the spirit and scope of the appended claims.
1. In a fluid amplifier having a power stream input duct for receiving fluid under pressure therein, a plurality of output ducts, a receiver section disposed in communication with said input and output ducts for passage of said fluid flow from said input to said output ducts, and a pair of control ports disposed in communication with the atmosphere and said receiver section, the improvement residing in an actuator carried by said fluid amplifier for selectively closing oif one of said pair of control ports while maintaining the other said control port open to the atmosphere to provide a pressure differential across said fluid in said receiver section to control flow of said fluid through a preselected one of said output ducts, said actuator including an arm secured on said amplifier, said arm having the distal ends thereof carried adjacent said control ports, energizing means for pivotal movement of said arm, movable means carried in each said control port, said movable means being secured to said ends of said arm for movement thereby for selectively opening opposite sides of said receiver section to the atmosphere, whereby responsive to the opening of one said control port and the closing of the other said control port a vacuum is created in said closed control port and a pressure differential is created across said movable means and said arm to assist said energizing means in the pivotal movement of said arm.
2. A device as set forth in claim 1 wherein said movable means includes a piston carried in each of said control ports for reciprocal movement therein; a piston rod carried by each of said pistons and connected to opposite ends of said arm for the reciprocal movement of said pistons responsive to energization of said actuator.
3. A device as in claim 2 wherein said pistons are provided with diameters larger than the areas of said control ports which open to the atmosphere to create an unbalancing moment across the flapper responsive to atmospheric pressure acting across the bottom of one of said pistons and thus provide a force to assist said energized solenoid in moving said pistons.
References Cited by the Examiner UNITED STATES PATENTS 3,072,147 1/1963 Allen 1378l.5 3,091,393 5/1963 Sparrow 137-81.5 3,176,703 4/1965 Sparrow 137-815 3,220,428 11/1965 Wilkerson 137-81.5
M. CARY NELSON, Primary Examiner.
W. CLINE, Assistant Examiner.