US3747644A

US3747644A - Electric to fluidic transducer

Info

Publication number: US3747644A
Application number: US00189631A
Authority: US
Inventors: D Tompsett
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1971-10-15
Filing date: 1971-10-15
Publication date: 1973-07-24
Anticipated expiration: 1990-07-24

Abstract

A fluid logic element is disclosed in which the point of attachment of a power jet to an offset wall is selectively controlled in response to an applied electrical signal. The electrical signal is applied to a piezoelectric element positioned to form a side wall of the nozzle generating the power jet. The bending of the element in response to the applied electrical signal selectively reduces the width of the nozzle. Since the point of attachment of the power jet to the offset wall is a function of the nozzle width, controlling the nozzle width by selectively positioning the element permits the attachment point to be controlled. The resulting logic device has outputs which are energized in response to the particular attachment point selected.

Description

i 1111 3,747,644 1451 July 24, 1973 1 ELECTRIC T0 FLUIDIC TRANSDUCER [75] Inventor: David Elliott Tompsett, Columbus,

Ohio

[73] Assignee: I Fell Telephone Laboratories,

Incorporated, Murray'l-lill, NJ.

22 Filed: Oct. 15,1971 21] Appl. 116.; 189,631

52 vs. (:1 137/825, 137/831, 235/201 ME [51] Int. Cl. F15 3/00 [58] Field of Search 137/815;

235/201 ME, 201 'FS Bowles 137/815 7/1967 I 3,540,463 11 1970 Meyer 137 815 3,456,665 7/1969 Pavlin l37/81.5

Primary Examiner-Samuel Scott Attorney-W. L. Keefauver et al.

57 ABSTRACT A fluid logic element is disclosed in which the point of attachment of a power jet to an offset wall is selectively controlled in response to an applied electrical signal. The electrical signal is applied to a piezoelectric element positioned to form a side wall of the nozzle generating the power jet. The bending of the element in-response to the applied electrical signal selectively re- Q References Cited I I duces the width of the nozzle. Since the point of attach- I I I 1 UNITED STATES PATENTS ment of the power jet to the offset wall is a function of 3,266,511 8/1966 TUl'lCk 137/815 the nozzle Width. controlling the nozzle Width by 891% 3,266,512 8/1966 Turick 137/815 tively positioning the element permits the attachment 3,148,691 9/1964 Greenblott. 137/815 point to be controlled. The resulting logic device has 8 5 1 1 1 outputs which are energized in response to the particu- I et a1. I... lat attachment selected 3,269,419 8/1966 Dexter... 137/815 3,283,766 11/1966 Horton 137/815 5 Claims, 8 Drawing Figures PATENTEUJUL 5. 747. 64 1 SHEEI 1 [If 4 FIG Pmmzuwm 5; 747; 644

SHEET 2 UF 4 FIG. 3

FIG. 4

ELECTRIC TO FLUIDIC TRANSDUCER BACKGROUND OF THE INVENTION This invention relates to fluid logic (fluidic) device and, more particularly, to a transducer for converting an electrical signal into a fiuidic output signal.

In many fluidic systems, input data is obtained from electrical apparatus, for example, a computer. It is necessary to provide someinterface apparatus between the electrical input system and the fluidic system to convert electrical signals into fluidic signals. A prevailing difficulty in constructing such a device has been the inability to obtain a small, simple, low-power device combining reasonable switching sensitivity and high reliability.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide an electrofluidic transduer that is small, low-power, inexpensive, reliable, and has good switching sensitivity.

In an illustrative embodiment of my invention, one side wall of a power jet nozzle of a fluidic device is formed by a piezoelectric element. An attachment wall is offset from the axis of the power jet. Deflecting the piezoelectric elementwith an applied electrical signal controls the effective width of the nozzle, thereby permitting the point wherethe power jet attaches to the offset wall to be selectively controlled. Positioning one or more output ports to coincide with selected points ofattachment produces a device-generating a fluidic output signal corresponding to particular electrical input signals.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of a transducer embodying my invention;

FIG. 2 is a plan view of the device in FIG. 1 showing the flow pattern fora power jet when no electrical signal is'present at the input;

FIG. 3 is a plan view of the device in FIG. 1 showing the flow pattern of a power jet when an electrical signal is present at the input;

FIG. 4 is a graphical representation of the relationship between nozzle width, wall offset, and point of attachment for the device in FIGS. 1-3;

FIG. 5 shows a second embodiment of my invention with the power jet flow pattern shown when no electrical input is present;

FIG. 6 shows the device-in FIG. 5 with the power jet flow pattern indicated when-a first electrical signal is present at the input;

FIG. 7 shows the device of FIG. 5 with the power jet flowpattern indicated when a second electrical input signal is present; and

FIG. 8 is a graphical representation of the relationship between nozzle width, wall offset, wall angle, and point of attachment for the device in FIGS. 5-.-7.

DESCRIPTION or THE ILLUSTRATIVE EMBODIMENTS presence of c'ross-sectional lines. It should be under stood that the devices could be constructed from any of the conventional materials used for fluidic devices.

FIG. 1 shows a simple device 20 embodying my in vention. An input nozzle 21 having a width b is formed on one side by a piezoelectric element 28. Nozzle 21 is located a distance D from an attracting wall 23 which is offset from the axis of the nozzleand to which a jet issuing from the nozzle can attach. An output port 22 is positioned along wall 23 to receive a jet attached to the wall. A jet which has not attached to wall 23 is deflected by splitter 24, located adjacent to output port 22, and dissipated through vent 25.

The point downstream from nozzle 21 at which the issued jet initially attached to wall 23 is indicated by the distance X The relationship between quantities b, D, and X is shown graphically in FIG. 4. Experiments have shown that this relationship, as depicted in FIG. 4, is essentially independent of the Reynolds number. These findings were reported by C. Bourque and B. G. Newman in Reattachment of a Two-Dimensional Incompressible Jet to an Adjacent Flat Plate, Aero Quarterly, Vol. II, 1960, p. 201.

Device 20 is shown in FIG. 2 with a series of arrows diagrammatically indicating the path a fluid jet would normally take through device 20. As the jet issues from nozzle 21, it begins to diverge and dip towards attachment wall 23. However, in accordance with the relationship shown in FIG. 4, output port 22 is located closer to nozzle 21 than the point of attachment. As a result,the issued jet is not received at output 22, but is deflected by splitter 24 to exit the device via vent 25.

When an electrical potential is applied to piezoelectric element 28, the fluid jet pattern shown in FIG. 3 results. Although the source of this electrical potential has not been shown, it would be well known to those skilled in the art. The application of a potential to element 28 causes it to deflect from its normal position. The width b of nozzle 21 is thereby reduced, creating a new nozzle 21 whose width would be lessthan that of nozzle 21. In accordance with the relationship of FIG. 4, it will be apparent that the decrease in width b will create a corresponding decrease in the attachment distance X Accordingly, the jet issuing from nozzle 21' will attach to wall 23 at or before output 22. Since this will cause the jet to be received at output port 22, the fluid logic signal resulting therefrom will be indicative of the presence of the electrical signal at element 28.

It is also possible to construct a device which embodies my invention and has a plurality of outputs. To facilitate control of such a multipleoutput device, the offset wall is probably best inclined at an angle to the nozzle axis. It is known that the attachment of a jet to an offset wall which is inclined at an angle to an issuing nozzle is also independent of the Reynolds number and dependent only on the device geometry. These findings were reported by C. Bourque in Reattachment of a Two-Dimensional Jet to an Adjacent Flat Plate," Advances in Fluidics, ASME, 1967. The relationship between the previously defined quantitiesb, D, and X and the wall angle a is shown in FIG. 8.

FIG. 5 shows a device having two outputs in which an offset wall 53 is inclined at an angle a to a nozzle 52. One side of nozzle 52 is formed by a piezoelectric element 51 to which electrical input signals can be applied, much the same as signals were applied to element 28 of device 20. Two

output ports

57 and 58 are located upstream of the normal point of attachment of a jet issuing from nozzle 52. Thus, the jet issuing from nozzle 52 will normally not be received by either output port but will be deflected by a splitter 55 and dissipated through a vent 56.

When no electrical potential is present at element 51, the fluid jet issuing from nozzle 52 will follow tha path indicated by the series of arrows in FIG. 5. The jet will diverge slightly and dip as it loses momentum leaving nozzle 52. However, since both

outputs

57 and 58 are upstream of the normal point of attachment, the jet is deflected by splitter 55 to exit the device via vent 56.

If a first electrical signal is applied to element 51, it will follow the path indicated in FIG. 6. The opening of nozzle 52 is reduced by the movement of element 51 in response to the signal, creating a nozzle 52' whose width is less than that of nozzle 52. The decrease in nozzle width will cause the point of attachment to move in accordance with the relationship shown in FIG. 8. As a result, the issued jet is received at output port 58 and a fluid signal is thereby generated which indicates the presence of the first voltage signal at element 51.

When a second electrical signal, having a greater potential than the first electrical signal, is applied to element 51, nozzle 52 is created. Nozzle 52" is narrower than both nozzles 52 and 52' due to the greater deflection of element 51 resulting from the increased potential applied to the element. In accordance with the relationship of FIG. 8, the attachment point will move even closer to the nozzle, creating the fluid jet pattern shown in FIG. 7. The issued jet is now received at output port 57 and a fluid signal is generated which indicates the presence of the second electrical signal at element 51.

It should now be readily apparent that a device having any number of outputs for generating fluid signals corresponding to applied voltages of predetermined strength may be devised. However, it should also be apparent that, as the number of outputs increases, the reliability of the devices decreases, as does the device sensitivity.

It should also be apparent that, although the embodiments disclosed show a maximum nozzle width when no voltage is applied to the piezoelectric element, the opposite condition could also be employed. That is, the element could be positioned so that the nozzle is a minimum width when no voltage is applied. Then, as the applied voltage is increased, the element could deflect to enlarge the nozzle width. Further,

piezoelectric elements

28 and 51 could readily be replaced by electromechanical, electromagnetic, or other means for controlling the nozzle width while still embodying the principles of my invention.

What is claimed is:

1. A fluidic device comprising a nozzle for generating a fluid jet;

an'attracting wall, offset from the nozzle, to which the jet may attach; and

means for selectively controlling the width of the nozzle to selectively determine the distance downstream from the nozzle where the jet initially attaches to the wall.

2. A fluidic device in accordance with claim 1 wherein the means for selectively controlling the width of the nozzle includes a piezoelectric element responsive to an applied electrical signal. I

3. A fluidic device in accordance with claim 1 further including a first output port located adjacent the attracting wall at a first distance downstream from the nozzle for receiving the jet generated by the nozzle when it has a first width.

4. A fluidic device comprising a nozzle for generating a fluid jet;

an attracting wall, offset from the nozzle, to which the jet may attach;

means including a piezoelectric element responsive to an applied electrical signal for selectively controlling the'width of the nozzle so that the point on the wall where the jet initially attaches is selectively determined;

a first output port located adjacent the attracting wall at a first distance downstream from the nozzle for receiving the jet generated by the nozzle when it has a first width; and

a second output port located adjacent the attracting wall at a second distance downstream from the nozzle for receiving the jet generated by the nozzle when it has a second width.

5. A fluidic device comprising a nozzle for generating a fluid jet;

a walled chamber into which the generated jet issues;

one wall of the chamber includes the nozzle, while a second wall of the chamber is offset from the nozzle and adapted to attract the issuing jet and cause attachment of the jet to the second wall at a point downstream from the nozzle;

means responsive to a plurality of input signals for selectively changing the width of the nozzle to correspond to particular input signals, the point of initial attachment of the jet to the wall being directly related to the nozzle width; and

a plurality of output ports for receiving the issuing jet and for producing fluidic signals corresponding to the input signals, the ports being located along the second wall at points related to the point of attachment occasioned by the selection of the nozzle width in response to the input signals.

Claims

1. A fluidic device comprising a nozzle for generating a fluid jet; an attracting wall, offset from the nozzle, to which the jet may attach; and means for selectively controlling the width of the nozzle to selectively determine the distance downstream from the nozzle where the jet initially attaches to the wall.

2. A fluidic device in accordance with claim 1 wherein the means for selectively controlling the width of the nozzle includes a piezoelectric element responsive to an applied electrical signal.

4. A fluidic device comprising a nozzle for generating a fluid jet; an attracting wall, offset from the nozzle, to which the jet may attach; means including a piezoelectric element responsive tO an applied electrical signal for selectively controlling the width of the nozzle so that the point on the wall where the jet initially attaches is selectively determined; a first output port located adjacent the attracting wall at a first distance downstream from the nozzle for receiving the jet generated by the nozzle when it has a first width; and a second output port located adjacent the attracting wall at a second distance downstream from the nozzle for receiving the jet generated by the nozzle when it has a second width.

5. A fluidic device comprising a nozzle for generating a fluid jet; a walled chamber into which the generated jet issues; one wall of the chamber includes the nozzle, while a second wall of the chamber is offset from the nozzle and adapted to attract the issuing jet and cause attachment of the jet to the second wall at a point downstream from the nozzle; means responsive to a plurality of input signals for selectively changing the width of the nozzle to correspond to particular input signals, the point of initial attachment of the jet to the wall being directly related to the nozzle width; and a plurality of output ports for receiving the issuing jet and for producing fluidic signals corresponding to the input signals, the ports being located along the second wall at points related to the point of attachment occasioned by the selection of the nozzle width in response to the input signals.