AU595684B2 - Tubular acoustic projector - Google Patents
Tubular acoustic projector Download PDFInfo
- Publication number
- AU595684B2 AU595684B2 AU11928/88A AU1192888A AU595684B2 AU 595684 B2 AU595684 B2 AU 595684B2 AU 11928/88 A AU11928/88 A AU 11928/88A AU 1192888 A AU1192888 A AU 1192888A AU 595684 B2 AU595684 B2 AU 595684B2
- Authority
- AU
- Australia
- Prior art keywords
- transducer
- side wall
- housing
- acoustic projector
- projector according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 239000000919 ceramic Substances 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- 230000004323 axial length Effects 0.000 claims description 3
- 239000007769 metal material Substances 0.000 claims description 3
- 101150066196 chi4 gene Proteins 0.000 claims 1
- 238000010292 electrical insulation Methods 0.000 description 3
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 2
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000036316 preload Effects 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004359 castor oil Substances 0.000 description 1
- 235000019438 castor oil Nutrition 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- ZEMPKEQAKRGZGQ-XOQCFJPHSA-N glycerol triricinoleate Natural products CCCCCC[C@@H](O)CC=CCCCCCCCC(=O)OC[C@@H](COC(=O)CCCCCCCC=CC[C@@H](O)CCCCCC)OC(=O)CCCCCCCC=CC[C@H](O)CCCCCC ZEMPKEQAKRGZGQ-XOQCFJPHSA-N 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/004—Mounting transducers, e.g. provided with mechanical moving or orienting device
- G10K11/006—Transducer mounting in underwater equipment, e.g. sonobuoys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
- B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
- B06B1/0655—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element of cylindrical shape
Description
595684 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 Form COMPLETE SPECIFICATION
(ORIGINAL)
FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: PI 0931 18 March 1987 e 0e *0 Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: FERRANTI plc Bridge House, Park Road, Gatley, Cheadle, Cheshire, England FRANK WOOD GRIFFITH HASSEL FRAZER 71 YORK STREET SYDNEY NSW 2000
AUSTRALIA
Complete Specification for the invention entitled: TUBULAR ACOUSTIC PROJECTOR The following statement is a full desription of this invention, including the best method of performing it known to me/us:r rr 1. ^a
I
2 CH14 TUBULAR ACOUSTIC PROJECTOR *e 0 00 0 0 00 0 0 0 *0 *0 0 0 The present invention relates to tubular acoustic projectors for use underwater.
A known tubular acoustic projector comprises a tubular ceramic piezo-electric transducer whose inner and outer cylindrical surfaces are electroded to convey a high differential drive voltage to the transducer. Electrical insulation is generally provided over the outer surface of the transducer to ensure that the two surfaces are isolated when submerged in water. The power handling capability of such transducers is limiced by the ability of the ceramic material to withstand tensile stress, and by the ability of the projector to dissipate the heat generated by the transducer which is a large proportion of the input energy. Failure to dissipate heat causes high temperatures which cause cavitation of the 15 surrounding water and which result in changes in the electrical, and ultimately mechanical, properties of the transducer.
It is known to delay the onset of ceramic failure through tensile stress by applying a band or winding, e.g. of fibreglass, in tension around the circumferences of the 20 transducer. However, the presence of such a band or winding introduces thermal insulation and thus aggravates the problem of heat dissipation, which is already severe since the electrical insulation itself has a heat insulating effect.
According to the invention, there is provided a tubular acoustic projector for underwater use, comprising a tubular ceramic piezo-electricl transducer having an outer cylindrical surface, and a housing including a side wall having a cylindrical inner surface which contacts said outer cylindrical surface of the transducer, said side wall compressing radially said transducer and, in operation, transmitting vibrations of the transducer to surrounding water, and the side wall being so thermally conductive as to dissipate to the surrounding water heat generated by the transducer.
The housing with the thermally conductive side wall thus removes heat from the transducer while radially compressing
*U
-3- CH14
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S.
S
S
*5 S S *5 55 0O S *r
S*
S
the transducer. This thus delays the onset of ceramic failure in the transducer without affecting adversely the electrical and mechanical properties of the transducer. This allows the transducer to be operated at higher powers than the transducers of known projectors.
The thickness of the housing provides an outer surface area for the projector which is greater than the outer surface area of the transducer, which has the beneficial effect of reducing the power output per unit area to the surrounding 10 water, thus reducing the tendency to cause cavitation of the water.
Preferably said side wall of the housing is formed of a metal material. The side wall may have cylindrical inner and outer surfaces.
15 One terminal of said transdv.cer is preferably provided on said outer surface of said transducer, the side wall of the housing being of a metal material and being in electrical contact with said terminal to provide an earth of the transducer.
The terminal may be provided by a metallic coating on said outer surface, said metal side wall being in direct contact with said coating.
The side wall is preferably of such an axial length as to extend beyond said transducer at both ends thereof.
The housing may be open ended, in which case the projector is provided with means for electrically isolating the inner surface of the transducer from its outer surface.
Alternatively, the side wall may terminate in open ends, with the housing including end closures which close said open ends to provide a sealed container for the transducer.
In this case, the interior of the housing is preferably filled with an electrically insulating liquid for insulating electrically the inner and outer surfaces of the transducer.
One of said end closures may be provided with one or more closable apertures for the filling of the housing with said electrically insulating liquid.
The housing may contain a device for balancing the pressure in said electrically insulating liquid with the CH14 pressure in water around the projector. This device may include a balancing diaphragm.
Preferably at least one of the end closures has, near the periphery thereof, a cylindrical groove which is wider in the radial direction than the radial thickness of the side wall, and which receives the corresponding end of the side wall.
This end of the side wall is then free to vibrate radially, unconstrained by the end closure.
In order to ensure that there is an effective seal 10 between the side wall and the end closure, there is a tight fit between the open end of the side wall and a radially inner cylindrical side of the groove, when the transducer is not 0000 o driven.
The invention further provides a method of manufacture 15 of a tubular acoustic projector for underwater use, comprising: forming a tubular ceramic piezo-electric transducer with an outer cylindrical surface, and then heat-shrinking onto said S- cylindrical surface, a cylindrical inner surface of a side wall of a housing so that said side wall compresses radially the 20 transducer and, in operation, will transmit vibrations of the .o S. transducer to the surrounding water, said side wall being so thermally conductive as to dissipate to the surrounding water heat generated by the transducer during operation.
00 In order that the invention may be better understood, a preferred embodiment will now be described, by way of example only, with reference to the accompanying drawings, wherein:- Figure 1 is a section through the axis of a tubular acoustic projector embodying the invention; Figure 2 is a section on the line A-A of Figure 1; and Figure 3 is an axial section through an end cap of the projector of Figures i and 2.
As shown in Figure 1, the tubular acoustic projector comprises a housing 10, having a cylindrical side wall 11 formed with a cylindrical inner surface Ila. The side wall 11 is integral with, and substantially thinner than, an end wall 12, which closes one end of the housing 10. The outer end of the housing 10 is closed by a removable end closure 13, similar in ia;-n CH14
S
S S I 55 .5
S
*SAS*
thickness to the end wall 12. The end closure 13 is secured in position by a bolt 14 which passes through a bore in the centre of the end wall 12, through a tubular spacer 16 extending coaxially between the end wall 12 and the end closure 13, and into screw-threaded engagement with a threaded bore 15 in the centre of the end closure 13.
The end closure 13 (as best seen in Fig. 3) consists of a tube 17 open at one end and at an opposite end integrally connected to the centre of a disk-like plate 18. The plate 18 10 has four bores 19 which lead from the hollow interior of the tube 17 to an inner face of the plate within the housing 10, as shown most clearly in Figures 2 and 3. These bores 19 are to receive respective cables, as described below. The plate 18 also has a cylindrical groove 20 cut into the inner face, near the periphery thereof. The end of the side wall 11 is received in this groove 20 and the arrangement is such that an end portion of the side wall 11 engages, and seals with, an axially extending inner cylindrical wall of the groove 20 when the transducer is not being driven.
The housing is of a strong, thermally and electrically conductive, non-corrodable metal such as stainless steel, although aluminium could be used.
A tubular transducer 21, formed by two identical, coaxial tubular, ceramic, piezo-electric transducer elements 21A, 21B, joined by an adhesive 22 at adjacent end faces, is disposed within the housing 10. The tubular transducer 21 has cylindrical inner and outer surfaces 23, 24 which are silvered for a purpose to be described below. The inner silvered surface 23 of each transducer element 21A, 21B has connected thereto a respective ring of narrow diameter wire (not shown) also for a purpose to be described below. The side wall 11 of the housing 10, which is electrically conductive, engages the silvered outer cylindrical surface 24 of the transducer 21 and provides an electrical earth connection therefor. The side wall 11 is such as to maintain the transducer 21 under radial compression, providing a compressive pre-load sufficient to r ~bni~li i i I; 1 -6- CH14 0* 0 *0 .q 0 *0 *00 0 avoid ceramic failure due to tensile stress induced, in use, in the transducer 21.
The ceramic transducer may be of PZT (lead zirconate titanate) or of a similar suitable ceramic material.
The electrical drive for the transducer 21 is provided as follows. Four insulated leads (25, 26, 27, 28) are threaded through an end seal 29, passed into the open end of the tube 17, and tien passed through respective bores 19, in the plate 18.
The end seal 29 seals the open end of the tube 17. As shown in 10 Figures 1 and 2, leads 27 and 28 provide an earth connection and are connected respectively to the end wall 12 and side w ,ll 11 of the housing 10. The leads 25 and 26 carry a high A.C.
voltage drive signal, and two conductors within each cable are soldered respectively on to the terminals of the inner surfaces 23 of the transducer elements 21A, 21B. These terminals are formed by the wire rings which, together with the silvered surfaces, distribute the drive signal evenly over the inner surfaces of the transducer elements.
The housing 10 is filled with an insulating liquid such as castor oil or transformer oil, which has good electrical insulation properties and good heat transfer properties through convection and conduction. Two holes 30 are provided through the end wall 12 of the housing 10 to allow the filling of the housing 10 with the liquid, and the holes 30 are sealed by grub screws 31. These screws 31, and the head of the bolt 14, are covered by a polyurethane seal 32, set into a circular recess in the end wall 12.
A diaphragm (not shown) may be provided in the housing, preferably in either the end closure 13 or the end wall 12, to equalize the pressure inside and outside the projector. The diaphragm may, for example, be a metal bellows.
The projector may be manufactured by heat-shrinking the side wall 11 over the transducer elements 21A, 21B, then securing the end closure 13 to the side wall 11, and finally filling the housing with the liquid and adding the seal 32.
The projector functions as follows. A differential A.C. voltage applied across the tubular transducer 21 by the n;m~rmrrmr*i;na*zn~slsr~- AI. i 7 CH14 leads 25, 26, 27, 28 causes it to vibrate radially, causing the side wall 11 of the housing to vibrate as shown by the arrows 33 in Figure i. The end wall 12, being thicker than the side wall, is rigid and prevents vibration of that portion of the side wall 11 adjacent the end wall 12. The opposite end of the side wall 11, however, is free to vibrate within the groove Thus acoustic vibrations are emitted by the side wall 11 of the housing.
It will be appreciated that in the projector described above with reference to the drawings, the transducer 21 is held g under radial compression by the side wall 11, so reducing thke tendency of the transducer 21 to crack under tensile stresses induced in the transducer 21 in operation. Further, the side wall 11, being thermally conductive, dissipates to the 15 surrounding water, the heat generated in the transducer 21 during operation. The side wall 11, being of greater diameter than the transducer 21, provides a heat-dissipating surface area o. which is greater than the surface area of the transducer 21, so o reducing the likelihood of cavitation in the surrounding water. This reduces the tendency of the transducer 21 to fail as a result of high temperature induced changes in the mechanical or electrical properties of the transducer 21.
Further, the side wall 11 provides an electrical earth for the 0transducer 21, so simplifying the electrical connections within 25 the housing 10. Since the side wall 11 is of metal, it is not degraded at high operating temperature.
The projector described above with reference to the drawings is thus capable of achieving high consistency of j performance in production since the pre-load and the thermal properties are defined by the design of the parts of the projector and are only minimally dependent on the production process used.
Although the e.ample illustrated has four cables 25-28, there is no need for any more than two electrical leads: an earth lead, connected to the side wall 11 and/or the end wall 12 of the housing 10, anc a lead conveying the A.C. drive signal to the inner surface or surfaces of the transducer 21.
CH14 It will be appreciated that the transducer 21 need not be formed of two transducer elements 21A, 21B; it could be formed of a single tubular element or of three or more tubular elements. The tubular element or elements may have any required axial length.
While the embodiment described above with reference to the drawings has the earth connection made by the side wall Ii, the earth connection coild be made direct to the transducer.
Further, although the side wall has been described as of metal, 1. 0 it could be made of any suitable material able to dissipate
S..
sufficient heat.
F urther, in the embodiment described above with reference to the drawings, the side wall 11 of the housing is substantially thinner than the end wall 12 and the disk 18.
15 This is not essential; indeed, it has been discovered that the side wall 11 may advantageously be as thick or thicker than the end wall 12 and/or the disk 18, thus increasing still further S. the heat-emitting outer surface area of the projector, and
S.
thereby improving heat dissipation. Acoustic isolation of the 20 side wall 11 from the end wall 12 could then be achieved by
C.
narrowing an annular end portion of the side wall 11 adjacent the end wall 12, forming a thin, flexible neck portion linking the side wall 11 and the end wall 12.
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Claims (12)
- 2. An acoustic projector according to claim 1, in which 1 the side wall of the housing is of such an axial length as to extend beyond the transducer at both ends thereof.1
- 3. A tubular acoustic projector according to claim 1 or claim 2, in which the side wall of the housing is formed of a a metal material.
- 4. A tubular acoustic projector according to claim 3, in which a terminal of the transducer is provided on its outer H cylindrical surface, and the metal side wall of the housing is 20 in electrical contact with said terminal to provide an earth of O the transducer. An acoustic projector according co claim 4, in which the terminal is formed by a metallic coating on the outer cylindrical surface of the transducer, and the metal side wall of the housing is in direct contact with said coating.
- 6. An acoustic projector according to any one of the preceding claims, in which the housing is open ended, and the projector is provided with means for electrically isolating the 1 inner surface of the transducer from its outer surface.
- 7. An acoustic projector according to any one of claims 1 to 5, in which the side wall of the housing terminates in open ends, and the housing has end closures which close said open ends to provide a sealed container for the transducer.
- 8. An acoustic projector according to claim 7, in which the housing is filled with an electrically insulating liquid for insulating electrically the inner and outer surfaces of the transducer. l f 10 CHI4/AU
- 9. An acoustic projector according to claim 7 or claim 8, in which the housing contains a device for balancing the pressure in the electrically insulating liquid with the pressure in the water which surrounds the projector during operation.
- 10. An acoustic projector according to any one of claims 7 to 9, in which at least one of the end closures has, near the periphery thereof, a cylindrical groove which is wider in the radial direction than the radial thickness of the side wall, and which receives the corresponding end of the side wall.
- 11. An acoustic projector according to claim 10, in which a Ithere is a tight fit between the open end of the side wall and a radially inner cylindrical side of the groove when the r transducer is not driven. A.
- 12. An acoustic projector according to any one of claims 7 15 to 11, in which one of the end closures is formed integrally o S* with the side wall of the housing.
- 13. An acoustic projector according to claim 12, in which *a ,the side wall is substantially thinner than the end closure to which it is integrally connected. S' 20 14. A tubular acoustic projector for underwater use o substantially as herein described with reference to, and as shown in, the accompanying drawings. A method of manufacturing a tubular acoustic projector 2 for underwater use, comprising forming a tubular ceramic piezo- electric transducer with an outer cylindrical surface, and then I heat-shrinking onto the cylindrical surface a cylindrical inner surface of a side wall of a housing so that said side wall compresses radially the transducer and, in operation, will transmit vibrations of the transducer to the surrounding water, said side wall being so thermally conductive as to dissipate to the surrounding water heat generated by the transducer during operation.
- 16. A method of manufacturing a tubular acoustic projector substantially as herein described with reference to the accompanying drawings. i" 11 DATED this FIPTEENTI-! day of FEBRUARY 1988 FERRANTI plc By their Patent Attorneys GRIFFITH HASSEL FRAZER a. S. a, 6 4 a as 3~b~ B a fa 6 a a, ass a a S 9 0 S ma 00 00 *0 *0 s a. a ae a. a ~.a aa*S*~ I qm L, 3 Af
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU11928/88A AU595684B2 (en) | 1987-03-18 | 1988-02-17 | Tubular acoustic projector |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPI0931 | 1987-03-18 | ||
| AUPI093187 | 1987-03-18 | ||
| AU11928/88A AU595684B2 (en) | 1987-03-18 | 1988-02-17 | Tubular acoustic projector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU1192888A AU1192888A (en) | 1988-09-22 |
| AU595684B2 true AU595684B2 (en) | 1990-04-05 |
Family
ID=25614664
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU11928/88A Expired AU595684B2 (en) | 1987-03-18 | 1988-02-17 | Tubular acoustic projector |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU595684B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU5946586A (en) * | 1985-07-01 | 1987-01-08 | Steedman Ltd. | Transducer mount |
-
1988
- 1988-02-17 AU AU11928/88A patent/AU595684B2/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU5946586A (en) * | 1985-07-01 | 1987-01-08 | Steedman Ltd. | Transducer mount |
Also Published As
| Publication number | Publication date |
|---|---|
| AU1192888A (en) | 1988-09-22 |
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