US3516428A - Fluidic rectifier device - Google Patents

Description

United States Patent Office 3,516,428 Patented June 23, 1970 3,516,428 FLUIDIC RECTIFIER DEVICE Donald L. ReXford, Schenectady, N.Y., assignor to enlral Electric Company, a corporation of New Filed Sept. 21, 1966, Ser. No. 581,085 Int. Cl. F15c 4/00 U.S. Cl. 137-815 7 Claims ABSTRACT F THE DISCLOSURE An analog-type fluid amplifier having the fluid receivers interconnected in a downstream direction provides a rectification action wherein a single polarity output is produced in phase with a bipolarity differentially pressurized input signal and varies proportionally therewith. The fluid receivers are spaced apart by a center vent and this separation dimension is critical for obtaining the most desirable input-output wave form characteristics.

My invention relates to fluid control devices commonly described as fluid amplifiers or fluidic devices, and in particular, to a specific fluidic device which performs a rectification of input control signals without causing a phase inversion thereof.

One of the several basic types of fluid amplifiers is of the momentum-exchange type wherein a main or power fluid jet is deflected by one or more control jets directed laterally at the power jet from opposite sides thereof. The power jet is normally directed midway between two fluid receivers and is deflected relative thereto by an amount proportional to the net sideways momentum of the control jets. This device is thereof often referred to as a proportional or analog device. Various computational and control systems are known embodying analog-type fluid amplifiers, and one of the basic functions often employed in these systems is that of rectification wherein a single polarity output signal is developed from a polarity input control signal. A fluidic device for performing a rectifier action is disclosed in a copending patent application Ser. No. 457,099, filed May 19, 1965, entitled Fluid Controls Particularly for Turbine Engines, inventors Willis A. Boothe et al. and assigned to the assignee of the present application. In such copending application, a single fluid receiver is employed in alignment with the power nozzle which generates the power jet. The characteristics of this fluidic rectifier device is such that the output pressurized fluid waveform is phase displaced from the input differential pressurized control fluid waveform by 180. In many fluidic circuits it is desirable to avoid this phase inversion between the input and output signals.

Therefore, one of the principal objects of my invention is to provide a fluidic rectifier device wherein the input and output signals are in phase.

In carrying out the objects of my invention, I provide a fluidic device wherein the power jet is normally directed midway between two spaced fluid receivers and is controllably deflected by a pair of oppositely disposed control fluid jets which are directed laterally at the power jet from opposite sides thereof. The fluid receivers are in communication with equal length fluid flow passages which are interconnected in a downstream direction to form a common output fluid passage wherein the downstream direction interconnection prevents free backflow of fluid from one fluid receiving passage into the other. The pair of fluid receivers are spaced apart and separated by a center vent passage having an input width which is substantially equal to the width of the power jet in order to obtain the most desirable input-output waveform characteristics for my rectifier device wherein a single polarity output pressurized fluid waveform is in phase with an input differential pressurized control fluid waveform which may be of bipolarity.

The features of my invention which I desire to protect herein are pointed out with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing wherein:

FIG. l is a top plan view of the fluidic rectifier device constructed in accordance with my invention; and

FIG. 2 is a graphical representation of the inputoutput characteristics of the rectifier device.

Referring in particular to FIG. 1, there is shown a View in top plan of a fluidic rectifier device constructed in accordance with my invention. The rectifier comprises a plurality of channels or fluid flow passages formed in a base member or through a plurality of superposed laminates, the channels being preferably of rectangular cross section although other forms may also be employed and being enclosed by a suitable cover plate or plates as in conventional fluid amplifiers. The essential elements of my fluidic rectifier device comprise a power fluid passage, a pair of control fluid passages (although a single passage may be used if the control signal is of bipolarity), a pair of spaced fluid receivers in communication with fluid passages interconnected in a downstream direction to form a common output fluid passage, and a center vent passage. The power fluid passage comprises a power fluid inlet passage 3 terminating in a restrictor or nozzle 4 for generating a power jet of pressurized fluid normally directed along the center axis of the device midway between two spaced fluid receivers 5 and 6. The control fluid passages comprise a pair of control fluid inlet passages 7 and 8 terminating in oppositely disposed nozzles 9 and 10, respectively. Each of the control nozzles is disposed adjacent the power nozzle 4 and substantially perpendicular to the power jet issuing therefrom whereby each control jet is directed against the side of the power jet in momentum exchange relation. The input to power fluid inlet passage 3 is connected to a source of substantially constant pressurized fluid by means of a conduit 11 extending through the cover plate of the device. The input to the control fluid inlet passages 7 and 8 is connected to a differentially pressurized signal source in the most general case wherein such source may be the two outputs of a particular fluid amplifier device in a fluidic circuit. The connection between the input to the control fluid inlets 7 and 8 and the source of the control fluid may be by means of conduits 12 and 13, respectively, as illustrated, or, my rectifier device may be formed in the same base member containing the fluidic device having its output connected to the control fluid inlets of the rectifier. In such latter case, the additional conduits 12 and 13 and associated fittings for connecting such conduits to the rectifier device input in fluid-type relationship are omitted. Fluid receiver 5 is in communication with a fluid flow passage 14, and fluid receiver 6 is in communication with a fluid flow passage 15 which passages are interconnected at their other ends in a downstream direction to form a common output fluid flow passage 16. The downstream direction connection prevents free back flow of fluid from one fluid receiving passage into the other. Receivers S and 6 are of equal width in the most general case and are spaced apart by a width greater than the width of the power jet in the region of the receivers. The separation between fluid receivers 5 and 6 contains the inlet to a center vent passage 22 which, though not by way of limitation 3 but in order to obtain the best operation of my device, has an input width substantially equal to the width of the power jet and greater than either receiver width. Center vent passage 22 has its outlet end extending through the cover plate and in communication with the ambient atmosphere as indicated by circular opening 23. Alternatively, passage 22 may be utilized as a center output to obtain the second side of a push-pull output signal in combination with receivers 5 and 6. A conduit 17 is in communication with passage 16 and extends through the cover plate to provide the outlet of my rectifier device. Fluid passages 14 and 15 are of equal length to avoid any phase displacement between the flows in the respective passages. The passages should also be of minimum length to reduce the time constant of the rectifier.

A pair of side vent passages 18 and 19 are preferably employed to relieve fluid pressure in the receivers resulting from unusual loading conditions, although my device is operable without these side vents. The -vent passages 18 and 19 are disposed adjacent receivers S and 6, respectively, on opposite sides of the power jet. The outer ends of the vent passages 18 and 19 extend through the cover plate and are in communication with the ambient atmosphere as indicated by circular openings 20 and 21.

The operating characteristics of my rectifier device are illustrated in FIG. 2 which is a graphical representation of the output fluid pressure in pounds per square inch gauge-p.s.i.g. (measured in conduit 17) as a function of the input differential control fluid pressure measured between conduits 12 and 13. These input-output characteristics illustrate the particular advantage of my device wherein the output pressure waveform is in phase with the input control pressure waveform. Thus, it can be seen that the output pressure is a direct function of the magnitude of input differential control pressure and is also independent of the direction or polarity of the input differential control pressure. The curves in FIG. 2 identified by the letters a and b were obtained in tests of a fluidic rectifier device constructed in accordance with my invention wherein the power nozzle had a width of 0.040 inch, each of the receivers had a width of 0.040 inch, the center vent passage inlet had a width of 0.080 inch and the spacing between the tip of the power nozzle and the inlet to the center vent passage was 0.270 inch. 'Ihe tests were conducted at a power fluid supply pressure of l p.s.i.g. Curves a and b were both obtained with the center vent passage being unrestricted, that is, opening 23 being open to the atmosphere. The unrestricted condition of the center vent passage obtains the best operating characteristics in that a minimum output fluid pressure is obtained for the condition of zero differential control fluid pressure (zero point) and the curve has a relatively sharp bottom at this zero point. Curve a was obtained with the output in conduit 17 being blocked, that is, a no load condition whereas curve b was obtained with a 0.020 inch diameter orifice inserted into conduit 17 as a load. It was found that the addition of a load to the center vent increased the output fluid pressure at the zero point. Also, the spacing of receivers 5 and 6 further apart obtains a more shallow bottom curve at the zero point as indicated by dashed line c. The wider receiver spacing also decreases the output pressure at the zero point by a small amount. A spacing of the receivers closer than illustrated in FIG. l increases the output pressure at the zero point and also reduces the gain, that is, the slope of the curve in the normal operating range. The receiver spacing for the rectifier device illustrated in FIG. 1 is optimized as evidenced by the curves a and b wherein a higher gain over a relatively large portion of the curve is obtained as compared to the gain obtained with curves for closer or wider receiver spacings and there also exists a relatively sharp bottom characteristic at the zero point.

My rectifier device has good operating characteristics over a power fluid supply pressure range of at least 1 to 15 p.s.i.g. Operation of the device at power supply pressures considerably below or above this range would require a change in the ratio of the dimensions (power nozzle width, receiver width, center vent width, power nozzle to center vent) which are illustrated in the FIG. 1 plan view.

It is apparent from the foregoing that my invention attains the objectives set forth. In particular, my invention makes available a lluidic rectifier device wherein the output signal is in phase with the input control signal as distinguished from a prior rectifier device wherein such signals are phase displaced by The desirable inputoutput characteristics of my rectifier device are obtained by spacing the fluid receivers further apart than in conventional analog-type fluid amplifier devices and by interconnecting the fluid receiving passages in a downstream direction to form a common output fluid passage.

Having described an embodiment of my fluidic rectifier device, it is believed obvious that modification andvariation of my invention is possible in the light of the above teachings. Thus, although the ratio of the dimensions illustrated in FIG. 1 provide a rectifier with many good characteristics, the pair of fluid receivers can be further spaced apart or spaced closer together, or the power nozzle to center vent spacing changed in order to obtain other specific characteristics, as desired. Further, it is to be understood that a single control fluid inlet passage terminating in a nozzle may be employed in place of the two passages and nozzles, and this arrangement obtains the characteristics of the FIG. 2 graph if the pressures of the control fluid signal vary above and below ambient or atmospheric pressure, i.e. are of bipolarity. Finally, it is recognized that the control means for controllably defiecting the power jet is not limited tothe use of pressurized control fluid jets, but may also include other known means employed in the fluid amplifier art.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An analog-type fluidic rectifier device comprising firstmeans for generating a jet of pressurized fluid,

a pair of spaced fluid receivers downstream from said first means for receiving pressurized fluid from a jet generated by said first means,

, said pair of fluid receivers spaced apart by the inlet to a first fluid passage means disposed therebetween, the width of the inlet to said first fluid passage means being substantially twice as great as the width of either of said pair of receivers for obtaining optimum operating characteristics of said device,

analog-type control means for controllably deflecting the jet generated by said first means relative to said spaced receivers in a proportional manner, and

second fluid passage means directly connected to said receivers for interconnecting said spaced receivers whereby the pressure of the fluid at the output of said second fluid passage means is independent of the direction of deflection of the jet generated by said first means and is proportionally directly related to the magnitude of the control exerted by said control means -to thereby provide the characteristics of a rectifier wherein the output fluid pressure is in phase with the control exerted by said control means and varies proportionally therewith over a particular operating range of said control means.

2. The fluidic rectifier device set forth in claim 1 wherein said control means comprises a pair of control fluid inlet passages terminating in oppositely disposed nozzles for generating oppositely directed control jets of proportionally varying pressurized fluid in intercepting relationship to the jet generated -by said first means, Ithe output fluid pressure varying proportionally with the pressure of the control jets over a particular operating range of control fiuid pressures. 3. The fiuidic rectifier device set forth in claim 1 wherein said first fluid passage means is aligned with the axis of said first means for generating a jet of fluid.

4. The uidic rectifier device set forth in claim 1 wherein the width of the inlet to said first fluid passage means is substantially equal to the width of the power jet thereat whose fiuid is distributed between said first fiuid passage means and one of said receivers over the particular operating range of said control means. 5. The fiuidic rectifier device set forth in claim 1 wherein said second fluid passage means comprise a first fluid passage directly connected to a first of said pair of receivers and a second uid passage directly connected `to a second of said pair of receivers, said first and second fluid passages interconnected in a downstream direction to form a common output fluid passage wherein the downstream direction interconnection prevents free back flow of fluid from one fluid receiving passage to the other. 6. The fiuidic rectifier device set forth in claim 5 wherein said first and second fluid passages are of equal length. 7. The fluidic rectifier device set forth in claim 1 wherein said pair of spaced fluid receivers are each of equal width.

References Cited UNITED STATES PATENTS 3,411,520 ll/l968 Bowles 137-815 3,192,938 7/1965 Bauer 137-815 3,266,509 8/1966 Bauer 137--815 3,340,885 9/1967 Bauer 137-815 SAMUEL SCOTT, Primary Examiner

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