Abstract: A method, system and apparatus for producing powerful seismic energy impulses by implosion of an imploding free piston positioned in a container which is adapted to be lowered down into a well in the earth to facilitate the collection of well surveying information about the geological formations of the earth in the vicinity of the well. Holding means maintain the imploding free piston in an initial position or quiescent state, trigger means suddenly release the holding means to cause the free piston to accelerate rapidly from its quiescent state thereby producing a powerful impulse by implosion, damping means arrest the movement of the imploding free piston, and operating means return the imploding free piston to its initial position after completion of its rapid acceleration and damped deceleration. After the imploding free piston is returned to its initial position, the apparatus may be triggered again, as desired, to produce additional powerful impulses by implosion.

Abstract: An inflatable attenuator having an inflatable resilient bladder enclosed by a perforated protective cylindrical housing is positioned in a liquid column in a well below (and if desired another inflatable attenuator is also positioned above) an impulsive energy source in the liquid column. The housing has an exterior diameter slightly less than the interior diameter of the well. The bladder is inflated when in the liquid column by gas supplied from a pressurized gas container attached to the attenuator or is supplied with pressurized gas through a hose line from a source of pressurized gas located on the surface of the Earth near the mouth of the well. A pressure-regulator responsive to the ambient hydrostatic pressure in the liquid column near the pressure regulator serves to maintain the pressure of the gas within the bladder at a regulated pressure at least equal to the ambient pressure in the liquid column where it is located.

Abstract: A long-life, low-maintenance air gun/hydro gun includes a one-piece, integral shuttle having an unusually long hollow shank with a firing piston whose configuration is the mirror image of the operating piston, except for the slightly smaller diameter "D" of the firing piston. The shank length L is at least 2.5 times D, and the whole shuttle is guided by this shank sliding within a shaft seal and bearing assembly. By virtue of this guidance, the perimeters of the operating and firing pistons are always kept slightly spaced from their respective associated cylinder walls for eliminating contact of these pistons with their cylinder walls for advantageously dramatically increasing the total number of operating firing cycles which can be accumulated in use before the need for replacing any worn parts, except for the operating and firing seals which are inexpensive. Thus, this air/hydro gun offers a low-maintenance feature.

Abstract: An airgun impulsive energy source has an elongated shaft bearing surrounding the shaft of the reciprocatable shuttle for guiding the shuttle and preventing its operating or firing pistons from contacting their respective cylinder walls. The illustrative embodiment of this airgun is proportioned to be self-firing with a fast repitition rate. This airgun has an elongated cylindrical housing with discharge ports in a cylindrical wall positioned between the operating and firing chambers. The shuttle-guiding shaft bearing is positioned in the cylindrical housing between the ports and an operating chamber. This shaft-guiding bearing has a length which is more than 1.

Abstract: A high ambient liquid pressure-resistant electrical connector is shown with an airgun having a solenoid actuated valve mounted on the airgun. A multi-conductor electrical cable is connected by this pressure-resistant connector to a plurality of terminals of the solenoid valve for protecting from ambient liquid the terminals and the adjacent portions of the conductors. This pressure-resistant electrical connector includes a connector housing having an upper end and a lower end, with the lower end of the housing being mounted to the airgun. The connector housing has a fluid sealant chamber for enclosing the electrical terminals and adjacent portions of the conductors connected to the terminals and includes at least one barrier for engaging the cable to protect against ambient liquid seeping past the barrier to the electrical terminals. The connector housing defines a cylindrical space carrying a spring-loaded piston.

Abstract: A seismic source is disclosed which is particularly useful for generating horizontally polarized shear waves in the earth for seismic surveying. It comprises an elongated, hollow, substantially vertical cylinder having an earth-contacting pad pivotally mounted to its lower end by a horizontal pivot shaft extending parallel with the front-to-back centerline of a transport vehicle. The lower surface of this large rigid pad contains multiple, blade-like teeth extending parallel with the pivot shaft for gripping the earth's surface for transmitting powerful horizontally polarized shear stress impulses into the earth. The cylinder contains a slidable piston-like reaction mass. The bottom of the cylinder is a strong upwardly diverging conical surface serving to focus and direct upwardly the discharge blast from each port of an air gun extending horizontally and with the axis of the air gun being oriented parallel with the pivot axis and being located a short distance above the pivot shaft.

Abstract: A marine air gun is advantageously converted into a hydro gun by substitution of two clamp rings and by convenient addition of various parts, allowing normal air gun firing by triggering with usual solenoid valve. In a presently preferred embodiment, a novel firing chamber is also substituted, providing outwardly-facing piston rings and cylinder encircling this chamber. A special clamp is substituted for that which normally secures operating chamber to firing chamber. An outer-cylinder-defining housing is concentric around the firing chamber, with an annular piston sliding in the annular cylinder space defined intermediate the firing chamber and the new outer housing. This annular piston is propelled by the air blast, suddenly ejecting water slugs from ports in the new outer housing. Also added is a pressure-controlled air-vent valve, responsive to air pressure coupled through passages in an adapter mounted between solenoid valve and air gun.

Abstract: An air gun is mounted in a reaction mass having an impulse-transmitting ground-contact plate movably mounted below the mass. This mass is in face-to-face contact with the plate over the major portion of the entire upper surface of the contact plate. Confined liquid is not employed. The air gun is charged with pressurized gas and fired, discharging the pressurized gas into the narrow horizontal interface region between reaction mass and plate. Rapid expansion of the discharged gas between mass and plate causes an intensely powerful seismic impulse to be transmitted into the earth. The air gun has a firing chamber for holding a charge of pressurized gas, a movable shuttle for suddenly discharging the pressurized gas, including upper and lower pistons with a hollow member connecting these pistons. A pedestal assembly carrying said shuttle is mounted from above to the reaction mass and extends down into the hollow shuttle member.

Abstract: A plurality of control station, watertight, submerged junction boxes are towed at spaced positions located along an airgun array, each junction box for including a microprocessor and data storage transmission capability, and airgun firing circuits to control predetermined airguns. The electrical cable for the array and the air supply lines, as well as the airguns to be controlled, are detachably coupled to respective junction boxes. Thus, the number of airguns in the towed array can be changed quickly and conveniently by coupling or uncoupling junction boxes and the associated airguns. A protective hose sheath extends between successive junction boxes and this hose sheath contains power lines and a communication bus, detachably connected to terminals in successive junction boxes. This hose sheath and interiors of junction boxes are pressurized with low pressure air during towing for excluding water in the event of a leak.

Abstract: A self-cleaning, high heat transfer wood or coal stove includes an interior cylindrical squirrel-cage configured fuel grate comprised of parallel air-conducting pipes for heating forced cold air. This arrangement of pipes not only provides for a self-cleaning stove interior due to the cyclical condensation and combustion of deposited effluents produced by combustion, but also greatly enhances the heat transfer capability of the stove by increasing the surface area available for heat exchange. The cyclical condensation and combustion is effected by incrementally rotating the interior cylindrical fuel grate by turning, using a handle inserted into one of a plurality of rod sockets which reside on the front of the stove. The stove of this invention is constructed with separate doors for convenient fuel loading and ash removal, and the fuel loading door is disposed to engage the combustion chamber opening with an air-tight and secure fit.

Abstract: A massive piston that does not strike anything during operation reciprocates with bouncing action up and down within a cylinder. An annular pressurized gas storage chamber encircles the piston and travels up and down with it. Pressurized gas is continuously supplied into this movable chamber to be temporarily stored therein. As the piston descends toward the lower end of the cylinder, pressurized gas from this travelling chamber is automatically suddenly allowed to bypass the lower portion of the piston, thereby injecting the pressurized gas into a bounce chamber between the descending piston and a bottom assembly. When this pressurized gas rushes through the bypass, it forces an exhaust valve closed.

Abstract: A massive piston, which might be called a "ram", except that it does not strike anything during operation, reciprocates with bouncing action up and down within a cylinder. An annular pressurized gas storage chamber encircles the piston and travels up and down with it. Pressurized gas is continuously supplied into this movable chamber to be temporarily stored therein. As the piston descends toward the lower end of the cylinder, pressurized gas from this travelling chamber is automatically suddenly allowed to bypass the lower portion of the piston, thereby injecting the pressurized gas into a bounce chamber between the descending piston and a bottom assembly. When this pressurized gas rushes through the bypass, it forces an exhaust valve closed.

Abstract: A seismic energy generating assembly includes a seismic energy generator positioned within a cage-like frame and adapted for vertical movement within the frame in reaction to the powerful seismic energy impulses that are transmitted downwardly into the earth. The assembly further includes hydraulic catch cylinders for easing the seismic energy generator back down to the ground within the frame after each impulse is generated. Horizontal extensions from this frame ride in guides formed by tubular channels for guiding the entire seismic energy generating assembly when lifted up from the ground by hydraulic lifting cylinders so that the assembly can be readily moved from place to place during seismic exploration. The tubular channels are pivotally mounted to an outer supporting frame on a land vehicle.

Abstract: Airgun apparatus are disclosed providing high strength, high pressure and large volume capabilities. An integral high-strength cylindrical housing extends for the full length of the airgun and gives a sleek overall cylindrical configuration. The components of the airgun advantageously are assembled within this cylindrical housing in two groups by sliding them in through the upper or lower end, respectively; moreover, either of the groups of components can be removed independently of the other. The components are pressed firmly together in place within the cylindrical housing by a strong screw-jack type of holding action, and tightening and locking apparatus is included on the airgun itself for enabling the mechanic to tighten and lock the holding means with enormous mechanical advantage.

Abstract: Firing of a seismic source of the type called an air gun is detected by means of a fluid pressure sensor located in the housing of a solenoid actuated control valve. Through a pressurized gas support port the pressure sensor is in fluid contact with a shuttle-operating chamber of the air gun, and the sensor detects a surge in fluid pressure resulting from rapid motion of the shuttle. if a misfire or malfunction of the air gun is detected by means of the fluid pressure sensor, the malfunctioning air gun can be shut down by actuating the solenoid valve, which is a novel dual action solenoid valve, thereby preventing pressurized gas from being supplied to that particular air gun. The valve includes a valve stem with radial gas inlet ports and radial triggering ports. A solenoid plunger is movable to close one or the other of the sets of ports.

Abstract: A powerful seismic impulse is generated in a body of water by a slug of water propelled from a seismic source by expanding pressurized gas, but the gas is retained in the source for use in subsequent firings. The seismic energy source, which is called a "hydro gun", is recharged by pumping an incompressible liquid, preferably, water, at high pressure into the gun to compress the retained pressurized gas. The hydro gun includes a firing cylinder, and a piston follower in the firing cylinder divides it into a liquid-charge chamber and a gas-propulsion chamber. The liquid-charge chamber is closed from liquid discharge ports by a shuttle which is held closed by the high pressure of gas in an operating chamber. By pumping an incompressible liquid into the liquid-charge chamber, the follower is forced to compress the pressurized gas which is trapped in the gas-propulsion chamber.

Abstract: Firing of a seismic source of the type called an air gun is detected by means of a fluid pressure sensor transducer in fluid communication with a shuttle-operating chamber of the air gun, and this sensor detects a surge in pressure in a portion of this chamber resulting from rapid motion of the shuttle, thereby producing an electrical signal which provides an accurate indication of the actual time of firing called the "shot instant" of the air gun. The reaction time between the electrical firing command signal and the shot instant is not the same for all air guns in a seismic survey array but may differ from one to another due to variations in the solenoid-actuated valves which trigger the air gun, in tolerances of the air gun parts, frictional effects and slight differences in mass of moving parts, and wear of parts. The method and apparatus as disclosed enables a geophysical survey crew accurately to determine the reaction time of each individual air gun seismic energy source.

Abstract: A seismic land source for transmitting powerful seismic energy impulses into the earth comprising a dome-shaped bell within which is contained a substantially incompressible liquid and an air gun which can be fired for abruptly releasing pressurized gas into the liquid in the bell. A metal pan is positioned below the rim of the bell for engaging the surface of the earth below the bell and is mounted for downward movement with respect to the bell. A flexible elastomeric diaphragm extends across the bottom of the bell above the metal pan and extends upwardly beyond the bell rim between the rim and the pan. The diaphragm has a rounded shoulder portion with an upturned peripheral side wall portion extending upwardly around the exterior of the bell to an elevated level substantially above the bell rim, and the upper edge of the peripheral side wall of the diaphragm is clamped at said elevated level to a flange fixed to the outer surface of the bell.

Abstract: A method and apparatus for simultaneously towing and handling multiple airguns are disclosed for use in marine seismic surveying which provide for ease in handling large numbers of airguns and enable them to stream out at a desired depth behind a submerged towing head in a long flexible streamer, or a plurality of simultaneously towed airgun streamers, whose level below the surface can be changed, if desired, while the survey is progressing. A plurality of airguns are included in each streamer extending for a length behind the survey vessel for providing an effective geographic diversity in the location of the airguns which can be simultaneously fired, or can be fired with time delay, for generating very powerful large area seismic energy wavefronts travelling down through the body of water. The buoyancy of the airgun streamer is controllable to provide neutral buoyancy during towing, if desired, and slight positive buoyancy to float the streamer in preparation for taking it on board the towing vessel.

Abstract: Improved pressurized gas discharging apparatus for use as a down-bore seismic impulse source provides a compact, efficient axially stacked assembly of components within a one piece elongated tubular shell housing having removable end closures. Within the tubular housing, removable partition means define a charge chamber and an operating chamber having an operating shuttle release means therebetween for sudden release of high pressure gas present in the charge chamber through a discharge port into the surrounding environment. Gas flow passageways for the supply of high pressure gas to the chambers extend longitudinally within the wall of the tubular housing and communicate with passages in the partition means. The shuttle release means may be actuated by a solenoid valve also removably positioned within the tubular housing for controlling gas flow through passageways also located within the walls of the tubular housing and within the partition means.