WO2012007743A4 - Underwater marker - Google Patents
Underwater marker Download PDFInfo
- Publication number
- WO2012007743A4 WO2012007743A4 PCT/GB2011/051299 GB2011051299W WO2012007743A4 WO 2012007743 A4 WO2012007743 A4 WO 2012007743A4 GB 2011051299 W GB2011051299 W GB 2011051299W WO 2012007743 A4 WO2012007743 A4 WO 2012007743A4
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- shell
- acoustic
- water
- reflector
- reflector according
- Prior art date
Links
- 239000003550 marker Substances 0.000 title abstract description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910000838 Al alloy Inorganic materials 0.000 claims abstract description 12
- 239000004411 aluminium Substances 0.000 claims abstract description 12
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 12
- 229910001369 Brass Inorganic materials 0.000 claims abstract description 3
- 239000010951 brass Substances 0.000 claims abstract description 3
- 239000011257 shell material Substances 0.000 claims description 88
- 239000004954 Polyphthalamide Substances 0.000 claims description 11
- 229920006375 polyphtalamide Polymers 0.000 claims description 11
- 239000011521 glass Substances 0.000 claims description 7
- 239000000835 fiber Substances 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 229920005989 resin Polymers 0.000 claims 1
- 239000011347 resin Substances 0.000 claims 1
- 229910045601 alloy Inorganic materials 0.000 description 6
- 239000000956 alloy Substances 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000003365 glass fiber Substances 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 229910052755 nonmetal Inorganic materials 0.000 description 4
- -1 poly(p-phenylene-2,6-benzobisoxazole) Polymers 0.000 description 4
- 239000004593 Epoxy Substances 0.000 description 3
- 238000009991 scouring Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229920000271 Kevlar® Polymers 0.000 description 2
- 229920006102 Zytel® Polymers 0.000 description 2
- 229920003235 aromatic polyamide Polymers 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 229920002577 polybenzoxazole Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920000785 ultra high molecular weight polyethylene Polymers 0.000 description 2
- 229920002292 Nylon 6 Polymers 0.000 description 1
- 230000004308 accommodation Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 150000002843 nonmetals Chemical class 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
Images
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
- G10K11/18—Methods or devices for transmitting, conducting or directing sound
- G10K11/20—Reflecting arrangements
- G10K11/205—Reflecting arrangements for underwater use
Definitions
- This invention relates to passive acoustic reflectors and markers for marking objects and other items of interest underwater.
- the word reflector is used generally to cover such devices.
- a passive acoustic reflector for use underwater and comprises a shell surrounding a core, said shell having one or a plurality of acoustic windows at more or more frequencies and through which acoustic waves at said frequencies may pass, at least in part, through the shell into the core to be focussed and reflected back from the interior of shell wall opposite said window(s), part of the wave also passes around the inside the shell and combines constructively with the reflected wave to provide a very strong output.
- Such reflectors although simple in concept, are quite sophisticated in their application.
- an acoustic reflector for use underwater is characterised in that it comprises a shell having at least one circular cross section surrounding a core said core being of water when the reflector is submerged in water.
- the reflector is characterised in that the shell is spherical, cylindrical (including tubular), toroidal, an ovoid or conical hollow body with one or a plurality of holes therein by which water may freely enter and leave the interior of the body when the body is in water.
- the shell wall is between 6 and 30mm thick, the circular cross section is between 200 and 400 mm in diameter and reflector is used in combination with an interrogating acoustic transmitter operating at 4 to 80 KHz, with peak performance at about 62KHz.
- Aluminium and its alloys work well for reflectors; ideally the circular section of the shell should be relatively small – no more than 400mm, larger balls taking up too much room.
- the shell wall should be no more than 15mm thick, metal shells less than 6mm thick are insufficiently rigid to be used in this application.
- a degree of optimisation of the interrogating frequency may be required in order to achieve best results for a given shell size and wall thickness.
- Figure 1 is a cross section a reflector according to the invention with an aluminium alloy shell
- Figure 2 is a cross section the reflector of figure 1.
- Figures 5A and 5B shows a toroidal reflector according to the present invention; figure 5A being a section on the line A-A’ of figure 5B and
- two hemispheres 13 and 14 comprise the shell 12 of a spherical acoustic reflector 10 according to the invention.
- the spherical shape of the shell 12 naturally provides the necessary circular cross section required for this invention.
- the hemispheres are made of aluminium alloy 6061T6.
- the shell is hollow.
- a number of holes 20 are provided in the hemispheres 13 and 14 communicating with the hollow interior 16 of the shell.
- the diameter of holes 20 is not critical -1mm to 2mm is typical; the diameter should be sufficient to allow air to escape freely from the hollow interior 16 of the shell 12 and for water to enter from outside of shell 12.
- a tongue 22 is provided around the rim 24 of one of the hemispheres 13.
- a groove 26 is provided on the rim 28 of the other hemisphere 14 to receive tongue 22 when the hemispheres 13 and 14 are assembled together.
- the tongue 22 is glued in place within the groove 26
- Non-metals to form the shell include epoxy impregnated carbon fibre, Kevlar® (aramid) fibre, Zylon® [poly(p-phenylene-2,6-benzobisoxazole) or PBO] fibre impregnated with epoxy resin, nylon 6, and epoxy impregnated polythene fibre (e.g. Dyneema®).
- FIG 3 the two hemispherical halves 13 and 14 of a reflector spherical shell 12 of a reflector in accordance with the invention are as described in figures 1 and 2.
- Other identical features are not described in detail but can be identified with reference to figures 1 and 2.
- One hemispherical half 13 of the shell 12 is provided with an internally treaded hole 34.
- the internal threads 36 of the hole co-operate with the external threads 42 of one end of bar 40.
- the other externally screw threaded end of the bar 40 may be screwed into a suitable internally threaded socket to mount the reflector in place.
- the bar 40 is made of the same material as the shell 12 of the reflector.
- Toroidal shaped reflectors are made in a similar way, from two halves of the toroid each having half circular cross section being joined together to form the final toroidal shape.
- Cylindrical or tubular reflectors made of aluminium or its alloys can simply be extruded. If a reflector is made of a non-extrudable material such as glass reinforced polyphthalamide, the manufacturing process is similar to that described in paragraph [0018] is used with two elongate halves of the cylinder or tube being brought together. For long tubes, this latter may not be entirely practicable, and a shell of an extrudable material such as aluminium or its alloys would be preferred for use in such cases.
- the shell wall is between 6 and 30mm thick
- the sphere is between 200 and 400 mm in diameter and reflector is used in combination, in the case of aluminium or its alloys, with an interrogating acoustic transmitter operating at around 60 KHz in the range 35 to 80 KHz.
- Aluminium and its alloys work well for smaller diameter spheres, clearly for the application envisaged the ball should be relatively small, larger spheres taking up too much room.
- steel shell reflectors performed well, steel is not the preferred material for underwater application in this invention because of its propensity to corrode, even if treated it is likely to deteriorate much more quickly than the alternatives.
- the target echo strength given was the best achieved for the given shell material and diameter.
- the response with a 200mm outside diameter shell was inadequate for practical use. It will be seen from the results that the response tends to be stronger as the cross section increases, but at the same time the best interrogating frequency decreases.
- shells made of epoxy impregnated fibres such as carbon fibre, Kevlar® (aramid) fibre, Zylon® [poly(p-phenylene-2,6-benzobisoxazole) or PBO] , or polythene fibre (e.g. Dyneema®) will display acoustic resonance behave in a resonance I a similar way to glass reinforced polyphthalamide, although optimum interrogating frequencies and shell thicknesses will vary.
- Brass can substitute for aluminium or its alloy and overall at the frequencies at which this invention operates best (4 to 80 KHz) metal shells perform better than non-metal shells.
- FIG 4 shows a schematic diagram of a pipe section 50 fitted with a number of aluminium tubular reflector s 52 each according to the invention.
- Each reflector has a hollow interior 54, with open ends 56 which, under water, allow water freely to enter and leave the interior 54.
- the tubes are isolated from the pipe sections 50 by conventional electrically insulating lugs 58.
- the pipe section 50 has conventional end flanges 60 with holes therein allowing it to be bolted to another pipe section.
- the pipe section with the reflectors can be prefabricated on land and joined by means of the bolt holes in the flanges 60 to another like fitted pipe. In this way, a pipe line fitted with acoustic makers can be assembled as part of the normal process for laying an underwater pipeline.
- the reflectors of Figure 4 work in exactly the same way as the spherical reflectors shown in figure 1 and 2.
- Acoustic waves at about 60 KHz transmitted from an acoustic source are incident on the tubular reflector 52.
- the tube 52 undergoes whole body vibration at this frequency which is rerated as an acoustic wave and is detectable at the source of original acoustic transmission
- tubular reflectors in figure 4 have been described in relation to a pipe section, the reflectors can be applied to other objects, such as oil rig platforms, accommodation platforms for workers at sea, and other objects to be placed under water
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
- Geophysics And Detection Of Objects (AREA)
- Aerials With Secondary Devices (AREA)
Abstract
Description
- Example 1 Water in steel spherical shell - outside shell diameter 300mm
- Shell Thickness 10.25mm
- Frequency 38.0KHZ
- Target Echo Strength = -10.1dB
- Example 2 Water in steel spherical shell - outside shell diameter 400mm
- Shell Thickness 14.0 mm
- Frequency 27.9KHZ
- Target echo strength = -7.6dB
- Example 3 Water in 25% glass reinforced polyphthalamide spherical shell - outside shell diameter 300 mm
- Shell Thickness 13.5 mm
- Frequency 12.0KHZ
- Target echo strength = -14.0dB
- Example 4 Water in 25% glass reinforced polyphthalamide spherical shell - outside shell diameter 400 mm
- Shell Thickness 15.5mm
- Frequency 9.0KHZ
- Target echo strength = -11.5dB
- Example 5 Water in aluminium alloy 6061T6 spherical shell - outside shell diameter 200 mm
- Shell Thickness 12.75mm
- Frequency 37.4KHZ
- Target echo strength = -16.7dB
- Example 6 Water in aluminium alloy 6061T6 spherical shell - outside shell diameter 300 mm
- Shell Thickness 18.75mm
- Frequency 25.2KHZ
- Target echo strength = -13.11dB
- Example 7 Water in aluminium alloy 6061T6 spherical shell - outside shell diameter 400 mm
- Shell Thickness 24.5mm
- Frequency 19.1KHZ
- Target echo strength = -10.6dB
- A similar response to that of example 7was obtained from an aluminium alloy 6061T6 sphere with a shell thickness 19mm thick broadly over in the
frequency range 28 to 35 KHz - Example 8 Water in aluminium spherical shell - outside shell diameter 300 mm
- Shell thickness 14mm
- Frequency 38 to 80 KHz
- Target Echo Strength better than -15db across frequency range
- Example 9 Water in aluminium alloy 6061T6 spherical shell - outside shell diameter 400 mm
- Shell thickness 11mm
- Frequency 38 to 80 KHz
- Target Echo Strength better than -15db across frequency range
- Example 10 Water in aluminium alloy 6061T6 spherical shell - outside shell diameter 200 mm
- Shell thickness 13mm
- Frequency 38 to 80 KHz
- Target Echo Strength better than -15db across frequency range
Claims (10)
- An acoustic reflector for use underwater characterised in that it comprises a shell having a least one circular cross section surrounding a core, said core being of water when the reflector is submerged in water.
- An acoustic reflector according to claim 1 characterised in that the shell has one or a plurality of holes therein by which water may freely enter and leave the interior of the body when the body is in water.
- An acoustic reflector according to claim 1 or 2 characterised in that the shell is spherical, cylindrical, toroidal, an ovoid or conical hollow body
- An acoustic reflector according to any claim 1, 2 or 3 characterised in that the shell material is selected from the group comprising a glass reinforced polyphthalamide, a resin impregnated fibre, or metal.
- An acoustic reflector according to claim 4 characterised in that the shell comprises a metal selected from the group comprising aluminium, aluminium alloy and brass.
- An acoustic reflector according to anyone of claims 2 to 5 characterised in that the shell wall is between 6mm and 30mm inclusive thick.
- An acoustic reflector according to claim 6 characterised in that the shell wall is spherical and between 200mm and 400mm inclusive in diameter.
- An acoustic reflector according to any preceding claim characterised in that it is in combination with an acoustic source operating at between 4 and 80 KHz inclusive.
- An acoustic reflector according to claim 8 characterised in that the reflector is in combination with an acoustic source operating at about 62KHz.
- An acoustic reflector according to any preceding claim characterised in that it is cylindrical and attached to a pipe.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE112011102375T DE112011102375T5 (en) | 2010-07-16 | 2011-07-11 | Underwater marker |
GB1300349.6A GB2494830B (en) | 2010-07-16 | 2011-07-11 | Underwater marker |
Applications Claiming Priority (10)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB1011939.4A GB201011939D0 (en) | 2010-07-16 | 2010-07-16 | Acoustic reflectors |
GB1011939.4 | 2010-07-16 | ||
GB1015563.8 | 2010-09-17 | ||
GBGB1015563.8A GB201015563D0 (en) | 2010-09-17 | 2010-09-17 | Acoustic reflectors |
GB1015952.3 | 2010-09-23 | ||
GB201015952A GB201015952D0 (en) | 2010-09-23 | 2010-09-23 | Acoustic reflectors |
GB201020536A GB201020536D0 (en) | 2010-12-03 | 2010-12-03 | Underwater marker |
GB1020536.7 | 2010-12-03 | ||
GBGB1107589.2A GB201107589D0 (en) | 2011-05-09 | 2011-05-09 | Underwater marker |
GB1107589.2 | 2011-05-09 |
Publications (3)
Publication Number | Publication Date |
---|---|
WO2012007743A2 WO2012007743A2 (en) | 2012-01-19 |
WO2012007743A3 WO2012007743A3 (en) | 2012-08-16 |
WO2012007743A4 true WO2012007743A4 (en) | 2012-10-18 |
Family
ID=45443129
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB2011/051299 WO2012007743A2 (en) | 2010-07-16 | 2011-07-11 | Underwater marker |
Country Status (3)
Country | Link |
---|---|
DE (1) | DE112011102375T5 (en) |
GB (1) | GB2494830B (en) |
WO (1) | WO2012007743A2 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB201121116D0 (en) | 2011-12-08 | 2012-01-18 | Grenoble 2 Sas | Acoustic reflectors |
WO2012101423A2 (en) | 2011-01-25 | 2012-08-02 | Subsea Asset Location Technologies Limited | Identification, detection and positioning of underwater acoustic reflectors |
GB2554765A (en) * | 2016-10-10 | 2018-04-11 | Subsea Asset Location Tech Limited | Autonomous unmanned submersible vehicle docking |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE439857C (en) * | 1924-10-21 | 1927-01-20 | Hans Hemmeter | Tea saver egg for repeated brewing of tea etc. like |
DE1934746U (en) * | 1965-12-11 | 1966-03-17 | Onno Behrends Fa | Infusion container for infusion beverages. |
US4176355A (en) * | 1978-01-12 | 1979-11-27 | Harris Stanley R | Radiation reflecting target surface |
GB2422282A (en) * | 2005-01-14 | 2006-07-19 | Secr Defence | Acoustic reflector |
IT1394049B1 (en) * | 2009-04-16 | 2012-05-25 | Milano Politecnico | SYSTEM AND METHOD OF DETECTION FOR THE MEASUREMENT OF THE PHENOMENA OF ALTIMETRIC VARIATION OF THE MARINE FONDALS |
-
2011
- 2011-07-11 GB GB1300349.6A patent/GB2494830B/en not_active Expired - Fee Related
- 2011-07-11 WO PCT/GB2011/051299 patent/WO2012007743A2/en active Application Filing
- 2011-07-11 DE DE112011102375T patent/DE112011102375T5/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
GB2494830B (en) | 2015-03-11 |
DE112011102375T5 (en) | 2013-04-25 |
WO2012007743A2 (en) | 2012-01-19 |
GB2494830A (en) | 2013-03-20 |
GB201300349D0 (en) | 2013-02-20 |
WO2012007743A3 (en) | 2012-08-16 |
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