US3402386A - Method and apparatus for generating sonic signals - Google Patents

Description

Sept. 17, 1968 s, RODBELL 3,402,386

METHOD AND APPARATUS FOR GENERATING SONIC SIGNALS Filed Dec. 26, 1963 T A v V IL I I Volume 5 1 I Time Fig. 3.

Magnet/c Pie/d 7'lme Fig. 4. P 3 N F" A a Pressure Time 30 lm/enfor Dana/O'SROO'b,

by 7M 35$? 3,402,386 METHOD AND APPARATUS FOR GENERATING SONIC SIGNALS Donald S. Rodbell, Burnt Hills, N.Y., assignor to General Electric Company, a corporation of New York Filed Dec. 26, 1963, Ser. No. 333,602 4 Claims. (Cl. 340-12) The present invention relates generally to the art of sonic signal generation and is more particularly concerned with a novel method of producing sonic signals and with unique apparatus implementing that method.

There has been a long-standing, generally recognized need for a method or means by which sonic signals could be produced over a broad frequency range in a variety of media. Sonic signals in useful frequency ranges can be generated by mechanical motion, as by a motor-driven piston, or by magnetostrictive or electrostrictive effects. Sonic impulses can also be produced by crystallographic conversions where these involve volume changes but for a variety of reasons, sonic signal generators, particularly sonar projectors, employ the dimensional linear change principle instead of volume expansion which might offer special advantages, particularly in very deep water applications.

The depth limitation and other shortcomings of modern sonic signaling equipment have long been recognized and have resulted in sustained research and development efforts. However, prior to the invention disclosed and claimed in the copending application filed of even date herewith in the names of Donald S. Rodbell, Ralph W. De Blois and Philip E. Lawrence, Ser. No. 333,600, filed Dec. 26, 1963, now abandoned, and assigned to the assignee hereof (the entire disclosure which is incorporated herein by reference), these efforts did not result in any breakthrough advance. Rather, the development of sonar projection equipment prior to that invention was confined to incremental improvements in apparatus operating on the principle of single dimensional linear change.

The present invention affords a new and effective way of using the basic concept of the aforesaid invention and in doing so may employ in a special form the invention disclosed and claimed in the copending application filed of even date herewith in the names of Donald S. Rodbell, Ralph W. De Blois, Ser. No. 333,601, filed Dec. 26, 1963, now abandoned, and Ronald H. Wilson and likewise assigned to the assignee hereof (the entire disclosure which is also incorporated herein by reference). Thus, in accordance with the present invention, a body of first-order phase transformation material such as a manganese arsenide rod may be caused to produce sonic signal pulses at double the input signal frequency without any increase in electrical power requirements. Furthermore, this result can be obtained without any significant offsetting disadvantage such as a reduction in the operating frequency range or diminished signal strength. In fact, at higher frequencies of the order of hundreds of cycles per second and higher, an additional advantage may be realized in that the latent heat involved in transition from one state to the other may be used as a flywheel since the energy involved is not dissipated to a significant extent during each cycle.

Basically, this invention involves repeatedly switching a body of first-order phase transformation material from its collapsed state to its expanded state and back again through the use of a magnetic pulse and a pressure pulse or sonic shock wave applied alternately to the body. Thus, in method terms, this invention broadly defined comprises the steps of causing the manganese arsenide or similar body in its collapsed state to undergo a firstorder phase transformation and thereby produce a shock nited States Patent wave and then subjecting the body to a sonic shock wave and thereby causing the body to undergo another firstorder phase transformation and produce a second shock wave in returning to its initial collapsed state. In actual use, this method preferably involves the frequent repetition of this cycle of expansion and contraction and there will be a predetermined interval between each first-order phase transformation which may be adjusted through apparatus design and in other ways, as will subsequently be described in detail. Also preferably, for certain purposes the resetting or collapsing action will in accordance with this invention be applied or implemented by an echo portion of the sonic shock wave produced by the magnetic pulse and the initial first-order phase transformation of each cycle resulting therefrom. Alternatively, it may be desirable in some instances due to echo attenuation or for some other reason to use some other pressure pulse source such as another sonic shock wave produced by the application of a magnetic pulse to a second manganese arsenide body or the like.

In its apparatus aspect, this invention generally described comprises a body of material having a firstorder phase transformation characteristic and having an annular side surface portion, a closed vessel containing this body and having an inner annular wall surface portion and a sonic signal-transmitting fluid in the vessel and surrounding and contacting the body and filling the space between the body and the opposing vessel wall surface. The body is disposed in the vessel with its annular surface portion substantially equidistantly spaced from the inner annular opposed surface portion of the vessel and a magnetic pulse source means is provided for subjecting this body to magnetic field pulses causing it to undergo a first-order phase transformation and thereby produce shock waves in the fluid contained in the vessel. While it will be understood that within this general definition a variety of shapes of bodies and vessels may be used, it is my preference to employ a rod-like body and to use a steel cylinder with the body disposed coaxially therein. It is further my preference to provide a liquid in the cylinder to transmit sonic shock waves from the body to the cylinder and back to the body for the purpose of resetting it. The magnetic pulse source means is preferably an insulated coil which is disposed around the body for maximum effect.

Those skilled in the art will gain a further and better understanding of this invention from the detailed description set out below, reference being had to the drawings accompanying and forming a part of this specification, in which:

FIG. 1 is a transverse sectional, partially diagrammatic view of apparatus incorporating this invention, including sonic signal generating means and signal read-out means;

FIG. 2 is a chart on which volume is plotted against time to illustrate the volume changes accompanying firstorder phase transformations in the course of signal generation in accordance with this invention;

FIG. 3 is another chart on which magnetic field is plotted against time, showing the effect of magnetic field pulses in producing first-order phase transformations and the resulting sonic signal shock waves;

FIG. 4 is still another chart on which pressure is plotted against time, the resulting curve indicating the incidence of the pressure pulses and their location in time relative to the magnetic field pulses and the volume changes of FIGS. 2 and 3; and

FIG. 5 is a view similar to FIG. 1 of apparatus embodying another form of the present invention.

With reference to FIG. 1, tank 10' containing a body of water 11 is equipped with sonic signal sensing readout means 13 exposed below the surface of the water body 11 and including a barium titanate transducer element indicated at 14 and leads 15 and 16 connecting element 14 operatively to a suitable read-out device 17. A closed cylidrical vessel 20 is disposed in tank 13 below the surface of water body 11 and is filled with a body of transformer oil 21. A solid cylindrical rod-like body of manganese arsenide 22 is disposed in vessel 20' and supported by suitable bracket means (not shown) coaxially of vessel 20. A magnetic coil or solenoid 24 is disposed around rod 22 an is connected by leads 25 and 26 to a current pulse source whereby magnetic field pulses of suflicient magnitude are generated and under the conditions of operation of the device cause switching of the manganese arsenide rod 22.

In the operation of the device of FIG. 1, rod 22 is initially in its collapsed state. This is indicated in FIG. 2. by the V symbol at its point of origin at zero time. After a brief interval of time, coil 24 is energized by a current pulse either through manually or automatically operated pulsing means as indicated by curve M of FIG. 3. As indicated above, the magnetic field resulting causes rod 22 to undergo a first-order phase transformation and to increase in volume producing a shock wave designated at T of FIG. 4 by the peak P The magnetic field is discontinued as the current pulse terminates but the rod 22 remains in its expanded state until an echo of the initial shock wave in liquid 21 returns from the cylindrical side wall of vessel 20. This occurs at time T as indicated by peak P of FIG. 4 and results in return of rod 22 to its collapsed state via a first-order phase transformation. Then again, after an interval of time represented by the spacing of T and T of FIG. 2, a magnetic field pulse is again applied to rod 22, as indicated in FIG. 3, transforming it once again to its expanded state and producing another shock wave in liquid body 21 indicated by the peak P of FIG. 4.

The stock waves produced by thus switching manganese arsenide body 22 from its collapsed to its expanded state are transmitted in part by vessel 20 to the surrounding water body 11 and are detected and read out through a detection apparatus 13. Vessel 20, thus, is of metal construction and has a relatively thin wall for effective sonic signal transmission to the surrounding medium. This vessel side wall, however, is effective also to reflect or echo a portion of the initial shock wave to reset manganese arsenide rod 22.

In the apparatus illustrated in FIG. 5, a tank 30, like tank 10, is provided as the container for the test apparatus and is nearly filled with a body of water 31. Again, sonic signal detection and read-out apparatus 33 is provided, including a barium titanate transducer sensing element 34 which is connected by leads 35 and 36 to a suitable conventional sonic signal read-out mechanism 37 disposed outside vessel 30.

Sonic signal generation apparatus of FIG. 5 comprises a dumbbell-shape metal vessel 40 providing two generally cylindrical chambers 41 and 42, communicating through a central passageway 43. The chambers and passageway of vessel 40 are filled completely with transformer oil body 44. A solid cylindrical body 46 of manganese arsenide-composite material is centered in chamber 41. Body 46 is of the type described in Example I of my copending application filed of even date herewith, and entitled, Composite Articles for Generating Sonic Signals and Method, Ser. No. 333,603, filed Dec. 26, 1963, now abandoned, and assigned to the assignee hereof, the entire disclosure of which is incorporated herein by reference. A similar manganese arsenide composite body 47 is similarly situated in chamber or compartment 42. S01- enoids 49 and 50 are disposed, respectively, around composite bodies 46 and 47 and are connected to current pulse sources (not shown) outside vessel 40 and tank 30 by means of leads 52 and 53 (for coil 49) and leads 54 and 55.

In the operation of the FIG. 5 apparatus, a sonic shock wave or signal from one composite first-order phase transformation body is used instead of an echo to switch the other body. Accordingly, the walls of vessel 40 may be substantially lighter and thinner than the side wall of vessel 20 to maximize sonic signal transmission into water body 31. Therefore, it will be understood that the operation of this apparatus involves alternately subjecting composite bodies 46 and 47 to magnetic field pulses to produce a first-order phase transformation and accompanying sonic shock wave in fluid 44 and also to thereby reset or collapse the other composite body in preparation for the next firing of it by a magnetic field pulse.

The frequency of oscillation of the devices described above may be selected on the basis of the dimensions of the vessel, that is, the distance between the point of origin of the resetting pressure pulse and the first-order phase transformation body to be reset thereby. In the case of FIG. 1, the sonic velocity of the signal in the liquids body taken together with the distance that the signal must travel initially and that the echo must return, fix the time between actuation and reset. Thus, the pressure wave produced on actuation initially travels away from the manganese arsenide body and in part is reflected back upon that body. But whether this apparatus or that of FIG. 5 or something else is used in carrying out this new method, the frequency of operation of these devices may vary over a wide range of preference although it will generally be desirable that the sequences be performed at hundreds of cycles per second and higher. An advantage in this practice is that the latent heat evolved in the transformations will not to any material extent be diffused away between switching operations, even under the most favorable heat-exchange circumstances.

It will be further understood that the apparatus of FIG. 1 and that of FIG. 5, another apparatus within the purview of this invention, may be operated in other environments than that provided by tanks 10 and 30. Thus, where the purpose is ranging or signaling purposes in large bodies of water, these tanks would not be used and the sonic signal might be generated at great depths and read out at such depths or near the surface by suitable conventional sonic signal detection means.

The following illustrative, but not limiting, examples of this invention as it may advantageously be carried out are offered to further inform those skilled in the art of the specific nature of the method and apparatus of this invention:

Example I A composite rod produced in accordance with Example I of my aforesaid copending application, entitled Composite Articles for Generating Sonic Signals and Method, is used as a shock wave or signal source. This rod, onesixteenth inch in diameter and four inches long is enclosed in a stainless steel cylinder eight inches long and held in place coaxially and longitudinally centered in the cylinder by means of spring clips secured to the cylinder end walls. The end walls and the side wall of the cylinder are of 16-gauge thickness and the cylinder is filled with transformer oil and sealed against leakage. This rod and cylinder assembly is disposed in a test vessel containing 50 gallons of water, with the stainless steel cylinder be ing disposed below the top surface of the water, and the rod is then subjected to magnetic field pulses by means of a solenoid coil disposed around the rod and connected to an electric power source outside the vessel, as indicated in FIG. 1 of the drawings accompanying this specification. The current pulses powering the coil are delivered at an appropriate frequency and the resulting sonic signals produced in the transformer fluid and transmitted to the surrounding test vat water body are detected and read out by a standard barium titanate transducer element and system presently in general use in under-Water signaling operations. Sonic signals are produced each time the coil is energized and at intervals immediately following, in-

dicating the resetting action of a pressure pulse or echo reflected by the vessel side wall.

Having thus described this invention in such full, clear, concise and exact terms as to enable any person skilled in the art to which it appertains to make and use the same, and having set forth the best mode contemplated of carrying out this invention, I state that the subject matter which I regard as being my invention is particularly pointed out and distinctly claimed in what is claimed, it being understood that equivalents or modifications of, or substitutions for, part of the specifically described embodiments of the invention may be made without departing from the scope of the invention as set forth in what is claimed.

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

1. Apparatus for continuous cyclic generation of sonic signals comprising a body of material characterized by having a magnetic first-order phase transformation, a closed vessel enclosing the body and providing a space between said body and a wall of the vessel, a sonic shocktransmitting fluid in the vessel filling space between the said body and a wall of the vessel, magnetic field source means operatively associated with the body and the vessel to subject the said body to magnetic field pulses in predetermined sequence and thereby cause abrupt changes in the specific volume of the body of at least 0.01 percent at predetermined intervals, and resetting means in the vessel and spaced from said body for generating sonic shock waves in the sonic shock-transmitting fluid to reset the said body after each actuation of the magnetic field source means.

2. The method of generating sonic signals which comprises the steps of subjecting a body of material having a first-order phase transformation characteristic in its collapsed state to a magnetic pulse of short duration and thereby causing the body to undergo a first-order phase transformation and produce a shock wave, then subjecting the said body to a pressure pulse and thereby causnig the body to undergo another first-order phase transformation and produce a second shock wave in returning to its collapsed state, and repeating the cycle to produce a series of sonic signals in predetermined pattern.

3. The method of generating sonic signals which comprises the steps of subjecting a manganese arsenide body in its collapsed state to a series of short-duration magnetic pulses and thereby causing the body to undergo a corresponding series of first-order phase transformations and produce a corresponding series of shock waves, and subjecting the said body to a series of pressure pulses alternating with the magnetic pulses and thereby causing the body to undergo another series of first-order phase transformations and produce a second series of shock Waves in returning to its collapsed state.

4. The method of generating sonic signals which comprises the steps of subjecting a manganese arsenide body in its collapsed state to a magnetic pulse of short duration and thereby causing the body to undergo a first-order phase transformation and produce a shock wave, then after a predetermined interval subjecting the said body to an echo of the shock wave and thereby causing the body to undergo another first-order phase transformation and produce a second shock wave in returning to its collapsed state, and then after another predetermined interval again subjecting the said body to a magnetic pulse of short duration and thereby causing the body to undergo another first-order phase transformation and produce a third shock wave, and then again resetting the manganese arsenide body to its collapsed state by subjecting said body to an echo of the third shock wave.

References Cited UNITED STATES PATENTS 2,728,901 11/1952 Millen 340-8 X 3,126,347 3/1964 Swoboda 252--62.5 3,140,942 7/1964 Walter -122 RODNEY D. BENNETT, Primary Examiner.

J. P. MORRIS, Assistant Examiner,

Claims (1)

1. APPARATUS FOR CONTINUOUS CYCLIC GENERATION OF SONIC SIGNALS COMPRISING A BODY OF MATERIAL CHARACTERIZED BY HAVING A MAGNETIC FIRST-ORDER PHASE TRANSFORMATION, A CLOSED VESSEL ENCLOSING THE BODY AND PROVIDING A SPACE BETWEEN SAID BODY AND A WALL OF THE VESSEL, A SONIC SHOCKTRANSMITTING FLUID IN THE VESSEL FILLING SPACE BETWEEN THE SAID BODY AND A WALL OF THE VESSEL, MAGNETIC FIELD SOURCE MEANS OPERATIVELY ASSOCIATED WITH THE BODY AND THE VESSEL TO SUBJECT THE SAID BODY TO MAGNETIC FIELD PULSES IN PREDETERMINED SEQUENCE AND THEREBY CAUSE ABRUPT CHANGES IN THE SPECIFIC VOLUME OF THE BODY OF AT LEAST 0.01 PERCENT AT PREDETERMINED INTERVALS, AND RESETTING MEANS IN THE VESSEL AND SPACED FROM SAID BODY FOR GENERATING SONIC SHOCK WAVES IN THE SONIC SHOCK-TRANSMITTING FLUID TO RESET THE SAID BODY AFTER EACH ACTUATION OF THE MAGNETIC FIELD SOURCE MEANS.

Images