Abstract:
The device hereof is most preferably an improved performance air gun as sound source for marine seismic exploration for petroleum deposits and it most generally is comprised of, an elongated cylindrical housing bored from each end to a fixed radial wall separating the two bores. The fixed radial wall having a through bore for hollow shaft of air control and release shuttle assembly to reciprocate within. The wall having fixed groove for elastomer shaft seal rings to seal around outside diameter of shuttle shaft and drilled passages for water entry to lubricate shaft seals. Air control end of shuttle assembly having set and release flange and internal bearing. Air release end of shuttle assembly cup shaped air release flange with bearing around outside diameter and seal means. Air control end of cylindrical housing having end cap drilled for air input means. The Air control end cap having bolt on shuttle support shaft with piston rings air input means air valving means and orifice means. The Release air end of cylindrical housing having attachable release air chamber sealing means and two air exhaust ports spaced opposite each other.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS/CLAIM FOR PRIORITY 
     This application claims priority, under 35 USC §119(e), to U.S. Provisional Application Ser. No. 61/268,936 titled: DEVICE FOR MARINE SEISMIC EXPLORATION FOR DEPOSITS, filed on Jun. 18, 2009. 
    
    
     FIELD OF THE INVENTION 
     Air gun, as used herein, is used as a sound source for marine seismic exploration for petroleum deposit. Following herewith is a more general description of the air gun used for seismic oil exploration and details of which are known well to all of ordinary skill in this and in related fields of technology: 
     Air Gun System 
     Like the water gun, the air gun is also a pneumatic sound source. The system consists of an onboard high-pressure air compressor and storage tanks, a shipboard electrical firing circuit controlled by a seismic recording system, and one or more air guns towed astern of a survey vehicle/ship/boat. On command from the seismic recording system, the air gun releases a specified volume of high pressure air into the water. The resulting release of air produces a steep-fronted intense sound pulse. 
     Air Gun System Operation 
     The Armed and Fired Configuration of an Air Gun: 
     The acoustic signal is produced by the explosive release of high pressure air directly into the surrounding water, the water in which the air gun is immersed. Note that during firing, the so-called air gun piston has been driven upward at a high velocity into the upper/operating chamber, while high-pressure air exits the lower/firing chamber into the surrounding water. 
     The air gun requires a high-pressure air compressor on board the ship that yields an air pressure of 2000-3000 psi. For maximum resolution, the smallest chamber size is used. If maximum penetration is the goal, a larger chamber is configured, but resolution is lessened. Both guns (the smaller chamber and the larger chamber guns) have a stable and repeatable pulse in terms of frequency composition and amplitude and can be tuned to optimize the source signature. 
     Air guns generate more signal strength than boomer, and sparker, and chirp systems. The air gun is towed astern. The return signals are received by an array of towed hydrophones. 
     Air Gun System Usage 
     The air guns are relatively deep penetration sources, operating with output frequencies of between 10 to about 1200 Hz, to identify subsurface geologic layers and define the subsurface structure. In studies that require less resolution but substantial penetration, the air gun is usually preferable as compared to a water gun, because it is far more efficient at producing low frequency energy. It can be used in fresh or brackish (less saline) water found in lacustrine and estuarine environments. Both air guns (and water guns) can be used in shallow water surveys and relatively deeper water environments, achieving resolution on the order of 10 to 15 meters and up to 2000 meters penetration. With proper tuning, the air guns work well in a wide variety of bottom types. Minimum operating water depths of about 10 meters are possible in acoustically soft bottoms. In areas with acoustically hard bottoms, deeper water depths of operation are required. 
     BACKGROUND OF THE INVENTION/DESCRIPTION OF THE PRIOR ART 
     There are no patents of which the Applicant and the inventor of the now disclosed invention is knowledgeable and thus none can be noted herein. Applicant is providing herein all of the information and understanding known by Applicant hereof to exist relative to the improved functioning and control of basic air guns as used for marine seismic exploration. The present invention provides many advantages considered significant and valuable by the inventor hereof. The inventor hereof has additional patents such as U.S. Pat. Nos. 3,379,273, 4,038,630, 4,271,924, 4,599,712, 5,432,757, 7,269,099. There are also some other inventors in the same field such as Fiske, U.S. Pat. No. 4,757,482, and others in the field. 
     SUMMARY OF THE INVENTION 
     The invention hereof very clearly is identifiable, at the present time, to the use of a newly designed air gun which novel and unobvious air gun invention basically uses similar methods of currently built and used air guns, but new ways and manners for providing pressurized air, new ways to locate and maintain firing controler and firing instant transducer of the air gun and to “fire” the air gun, and a new assembly of a basic form of an air gun which new assembly has at least an attachable and easily removeable control of functionality and features of the basic air gun. 
     It is an object of this invention to provide an air gun of high acoustical output, it is another object of this invention to provide an air gun of high reliability and it is a further object of this invention to provide an air gun for easy and quick field repair and maintenance. 
     The present invention as disclosed and claimed herein is most simply and most generally a modified and functionally improved air gun having substantially the following features and elements. 
     It is basically: 
     The device hereof is an improved performance air gun as sound source for marine seismic exploration for petroleum deposits. The improved air gun has as basic components thereof, an elongated cylindrical housing bored from each end of the air gun structure, thereby creating two (2) bores, to a fixed radial wall separating the two bores. The fixed radial wall having a through bore for hollow shaft of air control and release shuttle assembly to reciprocate within. The wall having fixed groove for elastomer shaft seal rings to seal around outside diameter of shuttle shaft and drilled passages for water entry to lubricate shaft seals. Air control end of shuttle assembly having set and release flange and internal bearing. Air release end of shuttle assembly cup shaped air release flange with bearing around outside diameter and seal means. Air control end of cylindrical housing having end cap drilled for air input means. The Air control end cap having bolt on shuttle support shaft with piston rings air input means air valving means and orifice means. The Release air end of cylindrical housing having attachable release air chamber sealing means and two air exhaust ports spaced opposite each other. Of major value for this invention is the incorporation of a multi-purpose manifold assembly. This multi-purpose manifold assembly is designed to be reasonably attachable and removeable from the other components of the improved air gun and it provides to the air gun high pressure air input and pass through, electrical and electronic cable input and pass through, as well as a firing circuit air gun trigger solenoid valve and hanger yokes and is secured to a flat surface milled on top of an air gun housing 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Based upon the fundamental characteristics of this disclosed invention, there are drawings of significance that add to the disclosure explanation or definition of this invention. Drawings are therefore included herewith. 
         FIG. 1  is a longitudinal cross section view of the present invention showing the detail structural features including the assembly of the improved air gun including the multi-purpose manifold attached and functionally connected to the elongated cylindrical housing: 
         FIG. 2 ,  FIG. 3  and  FIG. 5  are cross sectional end views respectively illustrating the present invention— FIG. 2  illustrates the input end side view, — FIG. 3  illustrates the output/firing end side view and— FIG. 5  illustrates the side cross sectional view of one of the air gun hanger yokes including the apertures for the signal cables and the high pressure air passageway; and 
         FIG. 4  is a longitudinal top view of the multi-purpose manifold of the present invention showing much of the detail structural features including the electrical control signal cables, the input cable and the air pressure supply conduit connected on the right side of the drawing and the output cable and the air pressure conduit both connectable or, connected to another improved air gun and illustrating, with dash line format, some detail of the control portion of the present invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     An air gun of the present preferred form is clearly illustrated and shown in the included herewith,  FIGS. 1-5 . Even though the basic features or characteristics of this invention relates to some significant changes in the basic air gun structure, a full and detailed description of the improved air gun of this invention is provided herewith. Many of the fundamental structural features of this air gun are shown in the combination of drawings in the  FIGS. 1-5  and many are not essential to the definition provided by the claims of the basic features of this invention but much detail of structure will be provided herewith. 
     In the detail that follows, reference is most of the time made to  FIG. 1  because  FIG. 1  depicts the overall improved air gun of the present invention. Details of  FIGS. 2 ,  3 , and  5  display some of particular structural details for the invention.  FIG. 4  is not referenced very frequently, but it does show a top view of a significant element—the multi-purpose manifold assembly  40 . 
     As is shown in  FIG. 1  the preferred air gun has a housing  1 , having a first bore  62  a wall  57  at its approximate mid section and a second bore  68 , wall  57  forms a barrier between a high pressure operating air chamber section  58  and ambient pressure air chamber  60  which forms the space  60 A which air chamber cup flange  5  of shuttle valve assembly  4  moves into when the air gun is triggered. Wall  57  has a bored groove  70  which houses two shaft seals  69 . Drilled holes  28  and  29 , allow water to flow into the space between the seals for lubrication. Shuttle assembly  4  consists of a hollow shaft  61 , an operating flange  14  and a release air chamber cup flange  5  held in place with nut  44  and sealed by o ring  121 . Air chamber cup flange  5  is secured with nut  4 A and has a split plastic rider ring bearing  6  which keeps it moveable and centered within bore  62  of air gun housing  1 . The operating flange  14  seals in the set position, when shuttle assembly  4  is in the “cocked” or set position as pictured in  FIG. 1  around its rounded outside diameter edge  11  against the inwardly beveled plastic or elastomer operating seal  10 . Cup shaped release air chamber flange  5  seals in the set position around its outwardly beveled sealing face  9 , against the inwardly beveled sealing face  8  of the plastic or elastomer release air seal  7 . The shuttle valve assembly  4  has a bearing grade plastic sleeve bearing  17  fit into bore  63 , retained by snap ring  18 . Sleeve bearing  17  is bored to a close sliding fit to the shaft  64  of shuttle guide shaft assembly  15 . Bore  62  has two opposite facing horizontal exhaust ports  56  from which the high pressure air volume  59  stored between shots in release air chamber  3  is released into the ambient water, generating a powerful sound impulse. The shuttle guide shaft assembly  15  keeps the shuttle assembly  4  centered in the air gun, but it is also the input conduit for high pressure air to flow into the operating chamber  58  and into the bores  65  and  25  of the shuttle  4 , entering the operating chamber  58  through radial holes  20 . Plugs  119  and  120  are welded in place. Taking notice to radial holes  19 , as shown in  FIG. 1 , radial holes  19  are open to air flow into bore  23 , but when the shuttle assembly  4  is in a position to the right of the set position, radial holes  19  are blocked by the bore  67  and bore  111  of shuttle assembly  4  acting to shut off air flow into bore  65  thru fill orifice  22 . The shuttle guide shaft assembly  15  is secured to operating chamber head  2  by bolt circle  72 . O ring seal  73  prevents high pressure air from leaking out from operating chamber  58 . 
     The operating chamber  58  has a liner sleeve  66  which retains the operating seal  10  but also controls the airflow around the operating flange  14 , as the shuttle  4  moves through its operating cycle from left to right and back again. Piston rings  16 , two or more, seal between the inner bore wall  67  of the shuttle and the outside diameter of the shaft  64  of the shuttle guide shaft assembly  15 , preventing high pressure air from flowing through that space into bore  65 , thus allowing the fill orifice  22  to control the rate of air flow into release air chamber volume  59 . When the air gin is triggered, the shuttle valve assembly  4  quickly moves from the set position as shown in  FIG. 1  to the right while un-seating the rounded outside diameter edge  11 , of the operating flange  14  and from the inwardly beveled sealing face  8  of the plastic or elastomer release air seal  7  and at the same time un-seating the outwardly beveled sealing face  9  of release air chamber cup flange  5  from the inwardly beveled face  8  of the plastic or elastomer release air seal  7 . When this happens, the shuttle assembly moves very rapidly to the right, the open end of air chamber cup flange quickly passes the air release ports  57  allowing the high pressure air stored in release air chamber  59  to explosively out through exhaust ports  56 . 
     Reference is made to  FIG. 4  which displays a multi-purpose manifold assembly  40 . (is multi purpose because it has in one unit, high pressure air input and pass through  39 . electrical and electronic cable input and pass through  41 , as well as the firing circuit  32  air gun trigger solenoid valve  30  and hanger yokes  112 ) is secured to a flat surface  83  milled on top of the air gun housing  1  by bolts  71 . A water tight cover  113 , has milled cavity  114  to provide space for electric wires coming up from electric passage conduit  41  through bore  42  as well as wires coming to the firing circuit  32  from transducer body  36  as well as wires to coil of solenoid valve  30  and for associated solder points on top of soldering terminal board  34 . A slot  120  is milled between solenoid valve cavity  76  and firing circuit chamber  75  for wires to pass between. Water tight cover  113  is secured to top portion of two chamber housing  74  by four cap screws  115  (only one screw shown), screwed into threaded holes  116 . An o ring seal  117  within groove  117 G milled around perimeter of cover  113  seals between cover and top surface  118  of two chamber housing  74 . (The groove is shown with dotted lines on top surface  118 , is actually in the cover but its path is shown for illustrative purposes). An electronic firing circuit  32  is pre-packaged in a plastic container  33  which fits closely in firing circuit chamber  75 , so that it can be removed for servicing or to facilitate changing. Manifold assembly  40  has a high pressure air passage  39  and conduit passage  41  for electric and electronic cables (cables not shown). A two chamber housing  74  contains firing circuit chamber  75  which contains electronic firing circuit  32  and a solenoid valve chamber  76  which contains solenoid valve  30 , and bore vertical  42  which is a conduit for electric conductor wires to pass from pass through conduit bore  41  up into firing circuit chamber  75 , to be connected at terminal board  34 , for servicing firing circuit  32 . Also within the housing is bore  77  which houses a transducer body  36  and the associated piezo electric transducer element  37  at the bottom portion  78 . The bottom portion  78  is in fluid communication with drilled passage  79  and milled slot  80  into the top portion of operating chamber  58 . O ring seals  81 ,  81 A and  81 B prevent high pressure air in operating chamber  58  from leaking either around the transducer body, or into the space between the bottom face  82  of the manifold assembly  40  and the flat milled top surface  83  of the air gun housing  1 . Operating chamber head cap  2 , is held in place with bolt circle  86 , O ring seals  84  and  85  prevent high pressure air from leaking out from gun fill passage  21 . The left end of  FIG. 1  as shown, has a firing air chamber  3  affixed to gun housing  1  by bolt circle  87 . The volume  59  of firing air chamber  3  as pictured is 20 cubic inches and the volume of the air chamber cup flange  5  is 30 cubic inches as pictured, together making a firing air volume of 50 cubic inches. Firing air chamber  3  can be produced and used, having volumes from ten or less cubic inches to two hundred cubic inches or more. O ring  12  prevents high pressure air stored within from leaking out and acts as well as a spring and centering device for plastic or elastomer release air seal  7  when the outwardly beveled sealing face  9  of the air chamber cup flange  5  is resting against the inwardly beveled sealing face  8  of plastic or elastomer release air seal  7 . The operating seal  10  has an o ring seal  13  which prevents air from leaking from operating chamber  58 , through vent passage  88  into ambient air pressure chamber  60 . 
     Returning to multi-purpose manifold assembly  40 . At the first end  98  of electric pass through conduit  41 , there is a connector assembly  46 , which has an input side  90  consisting of a tapered and barbed end  91  of input connector housing  45  which is held within a heavy duty reinforced hose conduit  43  secured by one or more band clamps  89 . Within the mating end  92  of input connector housing  45 , there is a first connector body  47  secured with snap ring  95 , which houses connector sockets (not shown). The solder terminal points for electric cables are at input end  93  of first connector body  47 . O ring  49  seals between housing  45  and first connector body  47 . 
     A second connector housing  53  of connector assembly  46  is welded at  94  to the electric cable conduit bore  41  input end of multi-purpose manifold assembly  40  and houses second connector body  48 . Connector body  48  contains the mating connector pins (not shown) which plug into the sockets of first connector body  47 . The correct orientation of the connectors when being mated, is assured by stainless steel dowel pins  51 . Two piece clamp ring  52  holds connector bodies  45  and  52  together (retaining flanges and bolts not shown). Solder terminal points at  97  provide electric connection for electric and electronic wires and cables as required by firing circuit  32 , and for other air guns which may be rigged in tandem with the air gun illustrated. At the second end  99  of electric pass-through conduit  41 , there is a heavy duty threaded and barbed hose fitting  100 , threaded into the second end of electric pass-through conduit  41 . A first end of heavy duty reinforced electric wire conduit hose  54  of length L, is fitted over the barbed portion of fitting  100  and secured by band clamp  101 . The second end of hose  54 , is fitted over the taper and barbed end of a second input connector housing  55  and secured by band clamp  102 . Second input connector housing  55  is a duplicate of input connector  45  at the input end of electric cable conduit bore  41 , but it is at the end of hose  54  of length L. Length L is long enough for desired spacing of another air gun next in line with in an array of air guns, and so on for each gun in each array. High pressure air pass through conduit  39 , passes through multi-purpose manifold assembly  40  having high pressure air hoses  105  and  106  of length long enough to match the spacing provided by electric wire conduit hose  54  and threaded hose fittings  103  and  104 , each threaded into an end of conduit  39  to bring high pressure air to and through the air gun. High pressure air pass-through conduit  39  has a branch off hole  107  drilled through the bottom surface of high pressure air conduit  39  and sealed from outward leakage by o ring seal  84 , supplying high pressure air to input air passage  21  drilled into operating chamber head cap  2  an into the base of shuttle guide shaft assembly  15  thus supplying high pressure air through radial ports  20  and  19  to air gun operating chamber  58 . Trigger valve high pressure air supply hole  38  is drilled through the top wall of air conduit  39  into position facing trigger valve air input chamber  108 , enabling trigger valve to be supplied with high pressure air. When the trigger valve  30  is actuated by an electric pulse from firing circuit  32 , a shot of high pressure air flows rapidly through trigger air passage  31  into annular space  109  to trigger the air gun. Air vent passage  88  is drilled through wall  57  near the bottom of operating chamber  58  and ambient air chamber  60 , thus allowing the air pressure in the annular space  109  to be at ambient pressure when the shuttle valve assembly  4  has returned to the set position as shown in  FIG. 1 . Check valve  27  positioned for outward flow, receives water or air from ambient air chamber  60  through drilled port  110 . If any water seeps into the ambient air chamber between air gun shots, it will be purged out through check valve  27  by the temporary air pressure build up in ambient air chamber  60  during the time the shuttle valve assembly  4  is moving from the set position as shown in  FIG. 1 , to the right, allowing some of the high pressure air to flow through drilled passage  88  into ambient air chamber  60  thus pressurizing the chamber  60  and pushing out any water which may have collected in the bottom out through check valve  27 . Shuttle assembly  4  outside diameter shaft seals  70  prevent high pressure air from operating chamber  58  from leaking out through clearance  131 , between the bore through wall  57  and the outside diameter of shuttle  4  shaft, when the shuttle is not in the set or cocked position. 
     Drilled holes  28  are a conduit for water to flow into and around shuttle outside diameter shaft seals  70  for the purpose of lubricating those seals for low friction when the shuttle assemble  4  is moving. When the shuttle assembly has returned to the set position the air pressure in ambient air chamber  60  returns to ambient. Plastic rider ring bearing  6  has a slightly smaller outside diameter than the bore  62  of airgun housing  1  allowing any remaining air pressure above ambient to seep out, or some water to seep into ambient air chamber  60  through exhaust ports  56 , between air gun shots which occur about every eight seconds. 
     Air guns are used as generators of sound pulses used for seismic exploration of geological formations which may contain petroleum deposits beneath bodies of water. The air gun sound sources are towed behind exploration vessels in groups or arrays, of ten to thirty guns more or less. beneath the surface of the water at depths typically at approximately thirty five feet. An exploration ship will have an air compressor on board capable of firing the air gun arrays at a pressure one hundred thirty three bar more or less. A computer controlled air gun firing system on the exploration vessel controls and monitors the firing of the air guns. Reference is again made by the inventor hereof to some other patents of applicant/inventor hereof such as U.S. Pat. Nos. 3,379,273, 4,038,630, 4,271,924, 4,599,712, 5,432,757, 7,269,099 and those of other inventors in the same field such as Fiske, U.S. Pat. No. 4,757,482, and others in the field. 
     The present Air Gun invention has advantages over applicant/inventor hereof&#39;s previous air gun inventions in that the shuttle assembly  4  is guided at one end with a bearing  6  on the outside diameter of the cup flange  5  and by bearing  17  on the inside  63  of the operating flange  14  end of the shuttle, allowing the shuttle to be shorter allowing the gun to be shorter and lighter. The bearing  17  acts as a sliding valve as it passes ports  19  and  20  in the shuttle guide shaft  15 . The greatest improvement over my past air gun inventions, is the feature of having a single multi-purpose manifold assembly  40  bolted to the gun housing  1  the firing circuit  32  and the trigger solenoid valve  30 , as well as transducer body  36  housed within. Because the manifold assembly has pass through conduits  39  and  41  for high pressure air and electrical conductors respectively, the often unreliable jumper hoses and electric cable jumpers used in conjunction with my previous designs, are eliminated. The air supply for the trigger valve in the present invention comes directly through a drilled hole  38  in the air conduit  39  into the valve  30 . The electric cables and wires passing through the electric cable pass through conduit, branch off into the vertical bore  42  and up directly into the firing circuit chamber  75 . There is a pipe threaded hole  122  for pipe plug  123  in top of water tight cover  113  and a drilled passage  124  between the bottom portion of pipe threaded hole  122  and milled cavity  114 . The purpose of these holes is for filling the electrical cavity and passages with an organic non toxic biodegradable oil for use to keep the wires and cables from moving or vibrating due to the movement caused by the firing of the air gun, thus lowering the possibility of wire breakage; another advantage of the present invention. Another advantage of having the valve mounted on the top side of the gun, is that the firing air passage  31  is shorter and less convoluted than with guns where the valve is mounted on the end of the air gun, thus the delay between triggering the valve and the firing of the gun is shorter and more accurately repeatable. 
     Another advantage of the present invention is, that the exhaust ports  56  face outward horizontally that when the gun is fired the high pressure air blasts out horizontally rather than in four or more directions as with guns with four or more ports. With air guns which the air blasts out vertically as well as horizontally, the water being rapidly pushed away rushes past the hangers, chains or cable the guns are suspended by. The force of this water pushing on the suspension means causes the suspension means to deflect in turn causing the gun to jump. This action causes wear and tear on the gun and suspension parts as well as the hoses and electric cables and wires. When the air blast comes out horizontally as in the present invention, it does not force water to rush against the suspension members. 
     Another advantage of this invention, is the way the operating seal  10  and the firing seal  7  are configured and operate. The operating seal  10  is inwardly beveled so that when high pressure air is introduced into the operating chamber  58  and the shuttle assembly moves to the set position as shown in  FIG. 1 , the rounded outside diameter edge  11  of the operating flange  14  seals against it and as pressure builds in the operating chamber  58 , the pressure building up on the outside diameter of operating seal  10  and its backup o ring spring-seal, forces them slightly inwardly, as the operating flange  14  of the shuttle assembly  4  is moving the last small fraction of an inch, towards the set position against surface  125  of wall  57 , assuring an air tight seal. The same type of sealing action occurs at the release air seal  7 , except that as the pressure  59  builds in the release air chamber  3 , builds up on the inside diameter of the release air seal  7  assisting its sealing ability against the outwardly beveled sealing face  9  of the air chamber cup flange  5 . Fill air control orifice  22  controls the rate at which high pressure air flows from operating chamber  58  into shuttle assembly bore  65  and through drilled passage  25  then into release air chamber  3 . 
     To Operate the Air Gun, which has been Placed in Water where it is to be Used, the following steps are to be followed: 
     A valve on board the exploration ship (not shown) is turned to the on position allowing regulated high pressure air to flow from the ships air pressure supply into hose line  105  which may be as long as one hundred feet more or less, into air pass through conduit  39  of multi-purpose manifold assembly  40  and into operating chamber  58 , through drilled air passage  21 . No matter what position shuttle valve assembly  4  is in, it will be pushed by the building pressure in operating chamber  58 , by acting of the area  130  presented by the difference in diameter between the inside diameter bore  67  and the outside diameter  61  of the shuttle valve assembly shaft, to the left as shown in  FIG. 1  until the rounded outside diameter  11  of the operating flange  14  seals against operating seal  10  and at the same time outwardly beveled face  9  of the shuttle assembly cup flange  5  seals against inwardly beveled face  8  of release air seal  7 . High pressure air fills release air chamber  3  volume  59  until the pressure in it is equal to the pressure in operating chamber  58 . At this point, the air gun is in the “cocked” pressurized state and ready to fire. It should be noted, that in the cocked state, the air gun is in a state of equilibrium, by the virtue of the fact that the surface area of the operating flange  14  presented to high pressure air in operating chamber  58  of the shuttle assembly  4  is a little larger than the surface area of the shuttle assembly cup flange  5  presented to the high pressure air  59  in release chamber  3 , while the air pressure in ambient air chamber  60  is presented to the inside side of both flanges, thus there is more force holding the shuttle valve assembly  4  in the somewhat stable cocked position and ready to be triggered. 
     Power supply and triggering wires or cables come from the control station on board the exploration ship and pass current and triggering control signals to the firing circuit  32  through inside conduit  44  of protective hose  43  into and through connector assembly  46  into electric wire and cable conduit bore  41 , into bore  42 , to firing circuit  32 . As the exploration vessel moves through the water towing one or more air gun through the water electric signals from the control center on the vessel cause the capacitor part of the firing circuit to discharge its charge into the coil  126  of solenoid valve  30  causing the armature  127  of the valve to lift up allowing a shot of high pressure air to flow valve air input passage  38  into valve air input area  108  past seal faces  128 , through valve output bore  129 , into drilled firing air passage  31 , then into the circular groove  109  around the inside face of shuttle operating flange  14 . The shot of high pressure air introduced into circular groove  109 , causes the shuttle assembly to move enough to break the seal between the rounded outside diameter  11  of the shuttle operating flange  14  and operating seal  10 , allowing high pressure air from operating chamber  58  to flow rapidly into the developing space between wall  57  and operating flange  14 , which removes the equalizing the pressure on both sides of flange  14 . At the point of pressure equalization around flange  14 , there still remains the high pressure air  59  in release air chamber  3 , which is pushing on the release air chamber side of the cup flange  5  which in the configuration pictured in  FIG. 1  is about thirty three square inches of area and at a typical firing air pressure of two thousand pounds per square inch, results in a force of sixty six thousand pounds of force pushing on a shuttle assembly weighing a few pounds. There is however a force opposing the accelerating of the shuttle assembly and that is the force of the high pressure air in operating chamber  58  pushing on the area  130  described by the difference between the outside diameter  61  and the diameter shuttle shaft bore  67  which area  130  is about one square inch, producing in comparison the small force of two thousand pounds. The shuttle assembly abruptly moves from the cocked position as shown in  FIG. 1  to the right, opening the ports to the surrounding water producing a loud report as the air exits the ports explosively. As the shuttle assembly nears the end of its travel to the fully open position, it is slowed and stopped by air compressing in operating chamber  58  and ambient air pressure chamber  60  and at the same time, the air in air release chamber  3  drops to nearly ambient as most of it exits the exhaust ports  56 , while air pressure in operating chamber  58  remains high and pushing on area  130  reverses the direction of shuttle assembly  4  returning it to set position as pictured in  FIG. 1 . The purpose of operating chamber bore  68  liner sleeve  66 , is to control the flow of high pressure air around the outside diameter as the shuttle  4  is moving through its cycle each time the air gun is triggered. From the cocked position when triggered, as the shuttle starts to move, air flows through clearance  132  between the outside diameter of shuttle operating flange  14  and the bore  133  of liner sleeve  66  allowing the shuttle to accelerate. When the operating flange  14  moves up to the middle area of the sleeve  66  where the bore has tapered to a larger diameter the air moves easily around the flange  14 , allowing the shuttle assembly  4  to accelerate more rapidly. When the shuttle assembly nears the top of its stroke, it travels at high speed, but when it enters bore  134  which is slightly larger than the outside diameter of flange  14 , the air trapped there compresses, slowing the shuttle, at the same time air  60 A is being compressed in ambient air chamber  60 , also slowing the speed of shuttle and stopping it before metal to metal contact happens. The shuttle next reverses direction, being pushed back to the set position by high pressure air in operating chamber, acting on area  130 . As operating flange  14  of shuttle assembly  4  approaches the set position it re-enters the smaller diameter bore of liner sleeve  66  with the small clearance  132 , compressing the air trapped between flange  14  and wall  57 , thus slowing the shuttle assembly before it reaches the set position. When the shuttle has returned to the set position the operating flange  14  seals against operating seal  10  while the outwardly beveled face  9  of cup shaped release air chamber flange  5 , seals against inwardly beveled sealing face  8  of the plastic or elastomer release air chamber seal  7 . High pressure air stored in operating chamber  58  and high pressure air coming into the air gun through drilled air passage  21  now flows through cross drilled ports  19  into drilled passage  23  through flow control orifice  22  through shuttle bore  65  through drilled air passage  25  to fill volume  59  of release air chamber  3 , equalizing at the same pressure as in operating chamber  58 . The air gun is now cocked and ready for the next shot.