US3454127A - Method of and apparatus for reducing the bubble pulse from underwater explosions and pressure impulses - Google Patents

Method of and apparatus for reducing the bubble pulse from underwater explosions and pressure impulses Download PDF

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Publication number
US3454127A
US3454127A US625133A US3454127DA US3454127A US 3454127 A US3454127 A US 3454127A US 625133 A US625133 A US 625133A US 3454127D A US3454127D A US 3454127DA US 3454127 A US3454127 A US 3454127A
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bubble
pressure
impulse
charge
gas
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US625133A
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English (en)
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Charles I Malme
Bill G Watters
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Bolt Beranek and Newman Inc
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Bolt Beranek and Newman Inc
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/38—Seismology; Seismic or acoustic prospecting or detecting specially adapted for water-covered areas
    • G01V1/387—Reducing secondary bubble pulse, i.e. reducing the detected signals resulting from the generation and release of gas bubbles after the primary explosion

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  • FIG. 4 3' United States Patent METHOD OF AND APPARATUS FOR REDUCING THE BUBBLE PULSE FROM UNDERWATER EX- PLOSIONS AND PRESSURE IMPULSES Charles I. Malme, Hingham, and Bill G. Watters, Gloucester, Mass., assignors to Bolt, Beranek and Newman, Inc., Cambridge, Mass, a corporation of Massachusetts Filed Mar. 22, 1967, Ser. No. 625,133
  • the present invention relates to methods of and apparatus for reducing or eliminating the bubble, secondary or cavitation pulse produced by underwater or similar explosions or other pressure impulses.
  • a further object of the invention is to provide a new and improved pressure-wave generating apparatus of more general utility, as well.
  • a method underlying the invention resides in locally introducing into the bubble being produced from the explosion or other impulse, gas pressure additional to any accompanying the generation of 3,454,127 Patented July 8, 1969 the impulse and rather critically at a controlled manner insuflicient in rate to generate its own shock wave but suflicient in quantity to cause the pressure within the bubble when it has substantially reached its maximum size to substantially equal the hydrostatic pressure outside the bubble.
  • Preferred constructional and other details are hereinafter set forth.
  • FIG. 1 of which is a longitudinal section of a preferred apparatus constructed to operate in accordance with the method underlying this invention
  • FIGS. 2A and 2B are explanatory wave-form graphs illustrating the operation of the invention and in which the ordinate plots pressure amplitude and the abscissa plots time;
  • FIGS. 3 and 4 are views similar to FIG. 1 of modifications.
  • monitoring apparatus when an explosive charge or other strong impulse source generates an underwater or similar impulse I, monitoring apparatus will detect reflections such as the signal II reflected from the surface of the water, for example, and spurious signals caused by the bubble pulse III and its surface or other reflection IV.
  • the impulse I was generated about thirty-five feet underwater with about 14 grams of explosive powder.
  • an electrically detonatable charge 1 is mounted within a sealed terminal section 2 of a nonattenuating container 3, as of thin-walled nondynamically constraining plastic tubing containing a fast propellant or high explosive 4, with the charge 1 extending also within an inner sealed plastic tube 5 carrying a deflagrating slow charge 6.
  • the initiating of the detonation at 1 will cause the fast explosive 4 to generate the main pressure impulse I, starting the formation of the bubble thereabout in the water or other fluid medium (hereinafter often generally referred to as underwater).
  • the slow charge 6, simultaneously initiated will slowly develop gas pressure within the bubble additional to that generated by the explosive 4 generating the impulse I.
  • this is done at a controlled rate related to the deflagration rate of the charge 6, insufficient to generate its own shock wave (which would produce deleterious impulses of its own), but in sufficient quantity, related to the relative volume of the charge 6, to cause the pressure within the bubble when it has substantially reached its maximum size substantially to equal the hydrostatic pressure outside the bubble, thus dissipating or suppressing the bubble without any substantial generation of secondary pressure pulses, as at III, FIG. 2B.
  • the deflagration of the charge 6 could be commenced after the detonation of the explosive 4 instead of simultaneous operation, as by the later ignition of the portion within inner container 5.
  • a detonator containing about five grains of PETN high explosive has been thus successfully employed, as shown in FIG. 1, within an outer thinwalled plastic container 3 about one inch in diameter and 3 /2 inches long containing a fast explosive propellant powder of the smokeless pistol powder type, and an inner substantially coaxially disposed plastic tube inch in diameter and 2% inches long containing a slow deflagrating charge of pelletized black powder, the weight of the latter being about equal to that of the former and having a pressure development rate of about 03x10 p.s.i. per second.
  • W and W are respectively the weights of the impulse producing and suppressing gas generating charges 4 and 6
  • F is an empirically determined specific force of the gas-generating charge 6
  • c is the volume of gas and solids per unit weight of charge 6
  • P is the hydrostatic pressure opposing bubble expansion
  • Q is the energy released per unit weight of the impulse-producing charge 4
  • K is the fraction of such released energy available for bubble oscillation. If the main charge 4 is TNT, for example, and smokeless deflagratory powder is used for the bubble-suppressing charge 6, then at depths of 500 fathoms or less, W /W may be calculated to have a value of the order of magnitude of about 0.5.
  • the suppression gas produced by the deflagration of charge "6 should be evolved preferably within a time interval of at least onetenth the bubble period such that this secondary, additional or repressurization gas evolution can be a subsonic process for charge weights of 10- pounds and up.
  • FIG. 3 the above-mentioned controlled and critically timed production of additional gas pressure during the bubble formation is attained with the aid of a volatilization-rate-controllable solid or liquid medium 10 adjacent the charge such as CCI F (Freon-ll), that permits the shock wave from the detonation at 1 to pass outward substantially unattenuated (in view of the initial solid or liquid state of 10), but, during the bubble growth, absorbs heat from the detonation and volatilizes at a controlled rate, dependent upon the nature and size of the medium 10, adding suflicient gas to that of the normal detonation to prevent the bubble from collapsing under the pressure of displaced water.
  • CCI F Reon-ll
  • a pressurized controlledcondensible gas cartridge 3' mounted by mechanical means 15 on the de-tonator 1 is caused to rupture upon detonation, again permitting substantially unattenuated outward transmission of the shock wave before the release of the pressurized gas within the cartridge 3' (as contrasted with prior art systems having initially present attenuating gaseous or similar media or rigid containers and the like), such release again being at the necessary controlled rate and quantity predetermined by the pressurization and volume of the cartridge 3.
  • Carbon dioxide cartridges of the type commonly used to inflate life vests (of about 10 cc. volume and pressurized to about 400 atmospheres) have thus been successfully used to suppress the bubble pulse.
  • the pressurized gas is stored adjacent the impulse genera-tor, it is to be understood that the invention has decided utility where the gas is stored at a remote location, but its release or introduction is effected within the bubble in the region adjacent the impulse generator.
  • a method of eliminating bubble pulses that normally follow the production of a strong pressure pulse that comprises, producing an energy impulse in a fluid medium, during the expansion of the bubble resulting from said impulse locally introducing within the bubble gas pressure additional to any accompanying the production of said impulse, and controlling the introducing of said additional gas pressure at an insuflicient rate to generate its own shock Wave but sufiicient in quantity to cause the pressure within the bubble when it has substantially reached its maximum size substantially to equal the hydrostatic pressure outside the bubble, thereby to prevent cavitative collapse of the bubble, the said introducing of gas pressure being effected by vaporizing a volatilization-rate-controllable medium adjacent the region of impulse production within the bubble but only after the commencement of the formation of the same.
  • a method of eliminating bubble pulses that normally follow the production of a strong pressure pulse that comprises, producing an energy impulse in a fluid medium, during the expansion of the bubble resulting from said impulse locally introducing within the bubble gas pressure additional to any accompanying the production of said impulse, and controlling the introducing of said additional gas pressure at an insutficient rate to generate its own shock wave but suflicient in quantity to cause the pressure within the bubble when it has substantially reached its maximum size substantially to equal the hydrostatic pressure outside the bubble, thereby to prevent cavitative collapse of the bubble, the said introducing of gas pressure being effected by actuating a deflagrating charge stored adjacent the region of impulse production.
  • F is the specific force of the deflagrating charge
  • a is the volume of gas and solids per unit Weight of the same
  • P is the hydrostatic pressure opposing the expansion of the said bubble
  • Q is the energy released per unit weight of the impulse-producing charge
  • K is the fraction of such released energy available for bubble oscillation.
  • a method of eliminating pulses that normally follow the production of a strong pressure pulse that comprises, producing an energy impulse in a fluid medium, during the expansion of the bubble resulting from said impulse locally introducing within the bubble gas pressure additional to any accompanying the production of said impulse, and controlling the introducing of said additional gas pressure at an insufficient rate to generate its own shock wave but suflicient in quantity to cause the pressure within the bubble when it has substantially reached its maximum size substantially to equal the hydrostatic pressure outside the bubble, thereby to prevent cavitative collapse of the bubble, the said rate being controlled such that the said introducing step is performed over a time interval during the bubble period such that it is elfected subsonically, said time interval being at least approximately one-tenth of the said bubble period.
  • Apparatus having, in combination, means for producing within a fiuid medium a strong energy impulse that would normally give rise to the generation of a bubble pulse, means disposed adjacent the producing means for introducing gas pressure additional to any accompanying the producing of said impulse and locally within said bubble as it expands, said last-named means being adjusted to introduce said gas pressure at a controlled substantially subsonic rate insufiicient to generate its own shock wave but sufficient in quantity to cause the pressure within the bubble when it has substantially reached its maximum size substantially to equal the hydrostatic pres sure outside the bubble, thereby to reduce tendency toward cavitative collapse, means being provided for en abling the said introducing means to introduce said gas pressure over a time interval at least approximately onetenth that of the bubble period.
  • Apparatus having, in combination, means for producing within a fluid medium a strong energy impulse that would normally give rise to the generation of a bubble pulse, means disposed adjacent the producing means for introducing gas pressure additional to any accompanying the producing of said impulse and locally within said bubble as it expands, said last-named means being adjusted to introduce said gas pressure at a controlled substantially subsonic rate insuflicient to generate its own shock wave but suflicient in quantity to cause the pressure within the bubble when it has substantially reached its maximum size substantially to equal the hydrostatic pressure outside the bubble, thereby to reduce tendency toward cavitative collapse, the impulse-producing means comprising a detonatable exploding charge disposed within a nonattenuating container.
  • Apparatus having, in combination, means for producing within a fluid medium a strong energy impulse that would normally give rise to the generation of a bubble pulse, means disposed adjacent the producing means for introducing gas pressure additional to any accompanying the producing of said impulse and locally within said bubble as it expands, said last-named means being adjusted to introduce said gas pressure at a controlled substantially subsonic rate insuflicient to generate its own shock wave but suiiicient in quantity to cause the pressure within the bubble when it has substantially reached its maximum size substantially to equal the hydrostatic pressure outside the bubble, thereby to reduce tendency toward cavitative collapse, there being provided adjacent the producing means a volatilization-rate-controllable medium comprising the said introducing means and in heat-exchange relationship with the energy produced by the said impulse in order to generate said gas pressure by its vaporization.

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  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
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US625133A 1967-03-22 1967-03-22 Method of and apparatus for reducing the bubble pulse from underwater explosions and pressure impulses Expired - Lifetime US3454127A (en)

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DE (1) DE1773022B1 (fr)
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3638752A (en) * 1968-09-13 1972-02-01 Commercial Solvents Corp Seismic signal generator
US4735281A (en) * 1985-02-20 1988-04-05 Pascouet Adrien P Internal bubble-suppression method and apparatus
US4976333A (en) * 1988-03-01 1990-12-11 Pascouet Adrien P Method for reshaping acoustical pressure pulses
CN112034506A (zh) * 2019-06-04 2020-12-04 中国石油天然气集团有限公司 二氧化碳震源控制器
CN112557620A (zh) * 2020-11-11 2021-03-26 安徽理工大学 电子雷管爆炸作功测试方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2599245A (en) * 1947-06-27 1952-06-03 Seismograph Service Corp Method and apparatus for seismic prospecting
US2619186A (en) * 1948-01-24 1952-11-25 Standard Oil Dev Co Seismic exploration method
US3292140A (en) * 1963-06-21 1966-12-13 Mobil Oil Corp System for generating seismic signals
US3371740A (en) * 1966-08-22 1968-03-05 Mobil Oil Corp System and method for reducing secondary pressure pulses in marine seismic surveying

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1208086B (de) * 1960-06-06 1965-12-30 Shell Int Research Erzeugen einer seismischen Schallwellenfront

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2599245A (en) * 1947-06-27 1952-06-03 Seismograph Service Corp Method and apparatus for seismic prospecting
US2619186A (en) * 1948-01-24 1952-11-25 Standard Oil Dev Co Seismic exploration method
US3292140A (en) * 1963-06-21 1966-12-13 Mobil Oil Corp System for generating seismic signals
US3371740A (en) * 1966-08-22 1968-03-05 Mobil Oil Corp System and method for reducing secondary pressure pulses in marine seismic surveying

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3638752A (en) * 1968-09-13 1972-02-01 Commercial Solvents Corp Seismic signal generator
US4735281A (en) * 1985-02-20 1988-04-05 Pascouet Adrien P Internal bubble-suppression method and apparatus
AU580386B2 (en) * 1985-02-20 1989-01-12 Adrien P. Pascouet Internal bubble suppression
US4976333A (en) * 1988-03-01 1990-12-11 Pascouet Adrien P Method for reshaping acoustical pressure pulses
CN112034506A (zh) * 2019-06-04 2020-12-04 中国石油天然气集团有限公司 二氧化碳震源控制器
CN112034506B (zh) * 2019-06-04 2024-04-30 中国石油天然气集团有限公司 二氧化碳震源控制器
CN112557620A (zh) * 2020-11-11 2021-03-26 安徽理工大学 电子雷管爆炸作功测试方法

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GB1168947A (en) 1969-10-29
DE1773022B1 (de) 1971-11-25

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