Controllable implosive sound projector

Abstract

The controllable implosive sound projector is comprised of a geometrically shaped cavity within a housing with a material across the face of the cavity. The air within the cavity is evacuated so as to form a vacuum causing a pressure differential to be formed across the material when the projector is submerged in a fluid. At a predetermined pressure differential the material is ruptured creating a shock wave at the face of the cavity which propagates into the cavity with a concave wave front deformation due to the confined boundaries of the cavity that forms a spherical shock wave at the interior of the cavity. At the focal point of the cavity, the spherical shock wave collapses and an impulse wave is generated that causes a pressure wave to radiate out from the opening into the fluid.

What is claimed is: 
     
       1. An implosive sound projector comprised of: a housing having a geometrically shaped cavity therein with an open end;   an end cap having an internal and external face sealing said open end of the cavity capable of being fractured when a predetermined differential pressure is applied across the end cap;   means for creating a vacuum within said cavity, the vacuum creating a differential pressure between the internal and external faces of the end cap when the projector is submerged in a medium; and,   means for fracturing the end cap upon reaching the predetermined differential pressure, allowing the medium to enter the cavity upon fracture causing a shock wave to be generated that propagates along the cavity walls focused to a point within the cavity where it collapses and creates a impulse wave which propagates out of the open end of the cavity into free space as a pressure wave.   
     
     
       2. An implosive sound projector, as in claim 1, wherein said means for fracturing the end cap is an end cap material having a predetermined fracture strength, the fracture being induced by the predetermined differential pressure across the internal and external faces of the end cap. 
     
     
       3. An implosive sound projector, as in claim 2, wherein material is a plastic sheet. 
     
     
       4. An implosive sound projector, as in claim 2, wherein material is a metallic film. 
     
     
       5. An implosive sound projector, as in claim 1, wherein said means for fracturing the end cap is a mechanical plunger activated by the predetermined differential pressure across the internal and external faces of the end cap piercing the end cap. 
     
     
       6. An implosive sound projector, as in claim 1, is further comprised of a means for replacing the end cap after fracture without removing the projector from the medium. 
     
     
       7. An implosive sound projector, as in claim 1, wherein the housing is made of a non-corrosive metal. 
     
     
       8. An implosive sound projector, as in claim 1, wherein the housing is made of a composite material. 
     
     
       9. An implosive sound projector, as in claim 1, wherein the housing is made of a material selected from a group consisting of non-corrosive metal and composite material. 
     
     
       10. An implosive sound projector, as in claim 7, wherein the non-corrosive metal is bronze. 
     
     
       11. An implosive sound projector, as in claim 7, wherein the non-corrosive metal is stainless steel. 
     
     
       12. An implosive sound projector to create acoustic wave at a predetermined external pressure comprised of: a housing having a first geometrically shaped cavity therein with an open end;   said first cavity filled with a material acoustically transparent to water;   a second cavity, a geometrically shaped portion of which protrudes partially into said first cavity;   said second cavity being filled with an incompressible fluid;   said first and second cavity having a common locus;   a plenum, partially filled with the incompressible fluid, connected to said second cavity so that the incompressible fluid flows between said second cavity and said plenum;   means for evacuating said plenum thereby causing the incompressible fluid to flow from said second cavity into said plenum thereby creating a vacuum in said second cavity;   means for generating an impact pressure wave in the evacuated plenum at the predetermined external pressure thereby creating a pressure wave in said second cavity as the incompressible fluid is forced back into the evacuated second cavity which collapses around the common locus and creates a impulse wave which propagates out of the open end of said first cavity into free space as an acoustic pulse.   
     
     
       13. An implosive sound projector, as in claim 12, wherein the material acoustically transparent to water is polyurethane. 
     
     
       14. An implosive sound projector, as in claim 12, wherein the means for evacuating the reservoir is a vacuum pump. 
     
     
       15. An implosive sound projector, as in claim 12, wherein the incompressible fluid is a hydraulic fluid. 
     
     
       16. A method for creating an acoustic pulse when submerged in a fluid to a predetermined pressure comprising the steps of: forming a geometrically shaped cavity within a housing having an open end;   sealing the open end of said cavity with an end cap that will fail upon application of a predetermined differential pressure across the end cap; and   creating a vacuum within said cavity, the vacuum creating the predetermined differential pressure between the fluid and the cavity, thereby causing the end cap to rupture allowing the fluid enter said cavity causing a shock wave to be generated that propagates along said calvities walls and is focused at a point within said cavity where it collapses and creates a reflected impulse wave which propagates out of the open end of said cavity as an acoustic wave into free space.   
     
     
       17. A method for generating an acoustic pulse when a device is submerged in a fluid to a predetermined external pressure comprising the steps of: forming a first geometrically shaped cavity in a housing that is filled with a material acoustically transparent to water, said cavity having an open end;   forming a second cavity in the housing that partially protrudes into said first cavity;   said first and second geometrically shaped cavity having a common locus;   creating a vacuum within said second cavity; and   injecting a medium under pressure into the vacuum created within said second cavity when the device is submerged in the fluid to the predetermined external pressure thereby causing a shock wave to be generated within said second cavity that collapse around the locus creating an impulse wave which propagates outward through the first cavity as a acoustic wave.   
     
     
       18. A method for replacing an end cap across an open end of an implosive sound projector without removing the projector from the submersion medium, comprising the steps of: winding a predetermined length of end cap material on rotatable shafts located at a first and second end of said material;   placing said material over the open end of the implosive sound projector cavity;   activating a takeup roller after failure of said material, drawing a new portion of material across the open end of the implosive sound projector; and   sealing the end cap material to the open face of the implosive sound projector by excavating a fluid within the cavity.