US2973739A

US2973739A - Underwater transducer

Info

Publication number: US2973739A
Application number: US119981A
Authority: US
Inventors: Nelson N Estes
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-10-06
Filing date: 1949-10-06
Publication date: 1961-03-07
Anticipated expiration: 1978-03-07

Description

March 7, 1961 N. N. ESTES UNDERWATER TRANSDUCER 2 Sheets-Sheet 1 Filed Oct. 6, 1949 3mm/vbo@ V. NESTES March 7, 1961 N. N. ESTES UNDERWATER TRANSDUCER 2 Sheets-Sheet 2 Filed 061i.I 6. 1949 3mm NN ESTES United States Patent O UNDERWATER TRANSDUCER Nelson N. Estes, 319 Pinewood Ave., Silver Spring, Md.

Filed Oct. 6, 1949, Ser. No. 119,981

4 Claims. (Cl. 116-137) (Granted under Title 35, U.S. Code (1952), sec. 266) This invention relates generally to sound generating apparatus and more particularly to a device of this character adapted for producing within a body of water acoustic signals of widely varying amplitudes and frequencies for actuating thereby acoustically sensitive mines or the like submerged therein.

Heretofore considerable diiculty has been encountered in sweeping mines of the acoustically sensitive type that are adapted to detonate responsively to the reception thereof of acoustical signals received thereby from the propellers of a passing ship. The principal diculty in sweeping mines of this character is that the controls therefor are generally set to respond only to such sound frequencies as are produced by the larger type vessels and thereby discriminating selectively therebetween and smaller surface vessels which may pass above such mines unharmed.

A further distinguishing characteristic of such mines is that their controls are frequently so designed as to respond only to selected rates of .approach to peak amplitude of the sound energy received thereby and which, while making such mines considerably more dicult to sweep, were primarily intended for delaying detonation of the mine until such time as the target vessel has moved within the effective range thereof.

To successfully sweep mines of the type indicated, it is necessary to duplicate artifically, within the water surrounding the mine, an acoustic signal similar in substantially every respect to that produced by a passing vessel. Of the various devices heretofore devised and employed to accomplish this, the most common form thereof is known as underwater speakers adapted magnetically to vibrate a diaphragm whereby acoustic signals are transmitted therefrom throughout the surrounding water. Such devices, though effective for short ranges, are highly vulnerable to sudden pressure increases as may be caused by the explosion of a mine in the proximity thereof and therefore, by reason of their initial cost and operation expense, are generally not considered practical for mine sweeping application. Other such devices including underwatersirens and the like generally lack the frequency response required for effectively sweeping mines of widely varying characteristics.

The device of the present invention possesses advantages over the prior art for the purposes disclosed not only in its simplicity of design but further by reason of its effectiveness of operation wherein a homogeneous mixture of steam and air is caused to be expelled at a controlled velocity through a vibratory nozzle portion Athereof whereby a continuous signal of predetermined frequency and high energy output is produced and caused to be radiated therefrom through the surrounding Vwater for actuation thereby of acoustically responsive rice A further object of the present invention is to provide an underwater transducer of high energy output capable of projecting throughout a predetermined submerged area an acoustical signal of a selectable frequency range.

A still further object is to provide a new and improved underwater transducer wherein the steam and air required for the operation thereof may be homogeneously mixed in proportions selectable for producing therein the operational characteristics desired.

A still further object is to provide an underwater transducer which is rigid in construction, inexpensive to manufacture yet highly efficient and accurate in its operation.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a view in section of the transducer according to a preferred embodiment thereof;

Pig. 2 is an enlarged sectional view through the vibratory nozzle assembly;

Fig. 3 is a sectional view of the vibratory nozzle taken along the line 3--3 of Fig. l, somewhat reduced and partly broken awa'y; and

Fig. 4 is a view in elevation showing the application of the device according to the arrangement thereof illustrated in Fig. l, as suspended from a vessel for movement thereof through the mine fields.

Referring now to the drawings and more particularly to Fig. 1 thereof, the transducer generally designated 5 is shown as comprising a cylindrical body portion 6 formed preferably from stainless steel, or the like, and including adjacent one end thereof a recess 7 wherein is threaded a closing plug 8 therefor. The recess 7 terminates into a thickened body portion at 9 whereby sulficient weight is provided thereby for maintaining stability of the transducer within the water during the operation thereof. Rising centrally from the base of the recess 7 and preferably formed as an integral part of the body is a stand pipe 10 the free end thereof being internally machined into a conically formed concave seat at 11 for receiving therein a correspondingly shaped nozzle end 12 of a flow adjustment screw 13 threaded with the cap piece at 14 and movable into or out of the seat 11 by rotation within the threads of the cap as a wrench or like tool is applied to the hex head portion 15 theroef.

Provided about the shank of the screw 13 is an annular groove 16 disposed in uid communication with an air supply tube 17 through intersecting

bores

18 and 19. Arranged for being received into a threaded mouth portion 20 of the bore 19 is a pipe section 21 onto which is sleeved the tube 17, the tube being thereafter secured to the pipe section as by clamp rings 23. v

The width of groove 16 permits considerable adjustv ment of the s'et screw 13 within the cap before fluid communication between the groove and bore i8 is interrupted. A bore 25 centrally disposed within set screw 13 and intersecting a transverse bore 26 in the latter is effective to communicate air from the groove 16 to the mouth of the nozzle end 12 of the screw, the air thereby being jetted into the bore of the stand pipe at a velocity controllable from the surface of the water by any suitable valve arrangement connected conventionally in the air supply. j

A bore 27 provided in the cap and arranged opposite the bore 19 is suitably threaded at 28 for receiving therein the threaded end section of a pipe member 29 adapted for communicating steam from a supply conduit 30, con- 0 nected therewith as by clamps 31, to the chamber 7,

the steam so admitted to the chamber thereafter being forced through the conically formed gap 33 and into the agrarias air stream from bore 25 thereby to mix therewith before being expelled from the ytransducer from between the lips of a vibratory nozzle assembly generally designated 35.

Adjustment of the gap 33, thereby to vary selectively the proportions of steam and air in the mixture, is accomplished by rotation of the screw 13 in a manner heretofore set forth either into or out of the mouth of the stand pipe l0, the screw thereafter being secured in an adjusted position by the tightening of the lock nut 36 thereon.

The nozzle assembly 35 is comprised of a tubular section 37 suitably threaded at 38 for being received into the threaded end portion of the bore 39 formed as a continuation of the bore of the stand pipe lil. The other end of the tube 37 is flattened at 40 for being received between a pair of exible vibrating elements 41 formed from any resilient material such, for example, 'as rubber and adapted for being secured along their edges, as shown, by plates 42 drawn into clamping engagement therewith as by rivets 43.

A suitable vulcanizing material applied to the outer surface of the tubular section 37 and the inner surface of the flexible element 41 provides an effective seal therebetween as at 44, Fig. 3, as the edge portions of the elements are drawn tightly over the tube and clamped between the plates 42 at the ytime of the nozzle assembly.

A bracket member 46, arranged over the pipe section 37, Figs. l and 2, and preferably furnace brazed thereto at 47, includes a pair of outwardly extending bifurcated arm sections 48 adapted for receiving between the'bifurcated portions 49 thereof the edge portions of the plates 4,2, Fig. 3. A plurality of bolts 50, arranged as illustrated, are effective when tightened to draw the forks 49 of the bracket to the plates and thus provide a rigid supporting structure for the nozzle from a position adjacent the transducer housing. Y

A ring member 52 secured to the head portion 15 of the adjustment screw at 54 is adapted for receiving `therein a cable ring 55 by which the transducer is suspended within the water from a supporting cable 56 therefor preferably arranged for depending from the bow end portion of the sweeping vessel 57 substantially as illustrated in Fig. 4.

Air and steam supplied respectively from the ships compressors and boilers when properly mixed within the transducer housing and discharged therefrom through the vibratory nozzle portion 35 thereof is effective to produce, for transmission throughout the surrounding water, an acoustic signal of great amplitude and of widely varying frequency characteristics controllable at will 'from the surface vessel by the regulation of the volume of the air and steam supplied therefrom. Acoustic signals of the character indicated when projected through the water before a moving vessel are generally effective to detonate each acoustically controlled mine 60 lying in the path of the vessel far in advance 'of lthe passing of ,the vessel thereover.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. it is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as speciiically described.

The invention described herein may be' manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent of the Uni-ted States is:

1. A transducer of the character disclosed for underwater sound transmission comprising, a housing, means including a discharge port in said housing for communieating steam from a source under pressure through said housing, means for introducing `air under pressure `into said steam communicating means for mixing the air homogeneously therein with said steam before the discharge thereof through said port, and a flat vibratory acoustic nozzle of generally triangular configuration and having Ithe interior thereof connected to said housing in fluid circuit with said port, said nozzle including a pair of resilient vibratory elements edge clamped along two sides thereof for exhausting said mixture therebetween through a normally closed outlet provided at the third side thereof, thereby to vibrate the elements responsively thereto whereby a low frequency acoustic signal is transmitted through the Vsurrounding water.

2. A transducer of the character disclosed for underwater sound transmission which comprises, a housing, means forming a passageway including a discharge port in said housing for communicating steam from a source under pressure through said housing, a mixing valve arranged in said passageway for controlling the flow of steam therethrough, means forming a part of said valve for admitting air from a source under pressure to said passageway for mixing the air therein with 'said steam before discharge of the latter through said port, and a flat vibratorynozzle of generally triangular configuration on said housing in fluid circuit with said discharge port and including a pair of edge clamped resilient plate members secured in face adjacency with respect to each other and adapted to exhaust therebetween the steam and air mixture from said housing thereby to cause the plate members to vibrate at selectable frequencies correlative to the air and steam ratio of the exhausting mixture passing therethrough whereby low frequency acoustic signals are transmitted through the surrounding water.

3. A transducer of the character disclosed for underwater sound transmission comprising, a cylindrically formed housing adapted Vfor submergence within a body of water and having therein a centrally disposed recess, a standpipe having a conically concaved end portion pro` jecting centrally upward from the base of said recess, an annular cap member disposed to close said recess thereby forming in said housing about said standpipe an annular chamber, port means in said cap for admitting steam from a source under pressure to said chamber for passing therefrom into the opening of said standpipe, an adjustment screw movable within said cap and having a conically formed end portion for being received into the concaved portion of said pipe for adjustably regulating the passage of steam thereinto, means forming a centrally disposed bore in said adjustment screw and terminating in a nozzle adjacent the apex of said conically formed portion thereof, means forming a port in said cap for admitting air from a source under pressure to said nozzle whereby the air is jetted therefrom into the opening of said pipe for mixing homogeneously with the steam in said pipe opening, means kforming a continuation of said pipe opening'terminating in `a discharge port and disposed for exhausting from said housing said homogeneous mixture, a flat vibratory acoustic nozzle of generally triangular configuration secured to the housing and arranged in fluid communication with said discharge port, saidl acoustic nozzle Vincluding a pair of resilient vibratory elements edge clamped at two sides thereof and disposed in face adjacency for receiving therebetween the mixture from said discharge port whereby an ocoustic signal is transmitted throughout the surrounding water as said elements are vibrated in response to the discharge of said mixture between the normally closed outlet provided at the third side of said acoustic nozzle. K

4. A transducer of the character disclosed adapted Yfor underwater sound transmission which comprises, a cylindrically formed housing for submergence within a body of water and having a centrally disposed recess therein, a standpipe having a conically concave end portion ex tending upwardly from the base of said recess,Y an annular cap member arranged for closing said recess thereby forming in said housing about said standpipe an Vannular chamber, y rnezms forming a port in said cap for admitting steam from a source under pressure to said chamber for passage therefrom to the opening of said standpipe, a screw having thereon a conically formed end section disposed to provide for adjustment of the opening of said standpipe for controlling selectively the passage of steam thereto, means forming a centrally disposed bore in said screw and originating at the apex of said conically formed end portion thereof to form a nozzle adapted for projecting within the concave por tion of said standpipe, means forming a port in said cap for admitting air from a source under pressure to said nozzle for jetting therefrom into the opening of said pipe for mixing homogeneously therein with said steam, means forming a discharge port in fluid circuit with said pipe opening and adapted for discharging from said housing said steam and air mixture, a triangularly congured vibratory acoustic nozzle assembly on said housing in fluid circuit with said discharge port and including a pair of edge clamped resilient vibrator elements, a tubular pipe section secured within said discharge port and including a iiattened portion disposed to extend between the surfaces of said elements, means including a pair of opposingly arranged plates for clamping said elements in face adjacency to the surface of the attened portion of said pipe section whereby the steam and air mixture discharged therethrough is expelled into the water from between the normally abutting surfaces of said elements to produce an acoustic signal for transmission through the surrounding water.

References Cited in the le of this patent UNITED STATES PATENTS 343,938 Williams June 15, 1886 852,646 Blake May 7, 1907 1,113,400 Baumgartner Oct. 13, 1914 1,169,090 Lucke Ian. 18, 1916 1,680,757 Yablick Aug. 14, 1928 1,927,054 Williams Sept. 19, 1933 2,350,187 Pfeiffer May 30, 1944