US2897755A - Ring actuated locking electrode for a towed firing line - Google Patents

Description

Aug. 4, 1959 G. M. PAVEY, JR

RING ACTUATED LOCKING ELECTRODE FOR A TOWED FIRING LINE 2 Sheets-Sheet 1 FiledMay 21, 1958 R .mw w .E V m M E G R O E G ATTORNEY Y 3 B h w E J wwl MN 5 L K w 1. l'li 1 h-- 2 |il|||||| 0N NN /m- QIN mm r 9 mm J 2 mm on R w 5 F mm RING ACTUAIED LOCKING ELECTRODE FOR A TOWED FIRING LINE Filed' May 21, 1958 Aug. 4, 1959 G. M. PAVEY, JR

2 Sheeghs-Sheet 2 INVENTOR.

' GEORGE M. PAVEYJR.

ATTORNEY Unite States Patent M RING ACTUATED LOCKING ELECTRODE FOR A TOWED FIRING LINE George M. Pavey, Jr., Dallas, Tex., assignor to Marine Research Company, Dallas, Tex.

Application May 21, 1958, Serial No. 736,835

17 Claims. (Cl. 102-16) This invention relates to devices for producing a seismic wave for seismic surveys of subaqueous geological formations and exploring oil-retaining subsurface terrestrial structures and more particularly to a firing line towed through the water by a vessel having means at the trailing end thereof for detachably securing a ring member having an explosive charge connected thereto and releasing the ring member only when the next succeeding ring member is engaged thereby.

In devices of this character heretofore devised it has been the usual practice to employ a firing line having one or more protnberances at the trailing end thereof engageable by a metallic ring to which the explosive charge is connected so constructed and arranged in juxtaposition to the protuberance for establishing an electrical connection from the towed line to the ring and thence to the firing charge. Alternatively the protuberance members may be actuated by an inertial device in response to the pressure wave caused by the explosion of the change to release the ring previously connected to the charge. Each of these arrangements is disclosed and claimed in my copending application for Firing Line for Subaqueous Geophysical Prospecting, Serial No.- 529,451, filed August 19, 1955, now Patent No. 2,870,708, issued Jan. 27, 1959. Still other firing line arrangements comprise :a rider provided with a pair of eye members slideable on the firing line and momentarily engageable by a pair of spaced contactors as the line moves through the eyes thereby closing a switch to fire the explosive charge attached thereto at the moment the contactors are engaged. Such an arrangement is shown on Patent 2,324,- 378 to J. W. Flude. This arrangement fails to establish a towing connection between the firing line and the explosive charge and the charge is fired at the moment of contact of the eye members with the contactors aforesaid. The charge is thus incapable of being towed to a more favorable position with respect to the seismic spread.

This disadvantage is obviated by the present invention by providing a firing line having a new and improved contact device at the trailing end thereof for locking the ring member thereto thereby to establish a towing connection to the explosive charge until the charge has been towed to -a desired firing position within the water and exploded at will by an impulse of firing current applied to the firing line by an operator on the towing vessel. In accordance with the teaching of the present invention the ring remains locked to the contact device until released therefrom by engagement of the next succeeding ring member with the contact device, as will more clearly appear as thedescription proceeds.

One of the objects of the present invention is to provide a new and improved termination for a firing line.

Another object is the provision of a locking device for the trailing end of a firing line in which an apertured member slideable therealong is locked thereto until released by a second apertured member subsequently moving into contact with the locking device.

A further object is to provide a locking device for 2,897,755 Patented Aug. 4, 1959 the trailing end of a firing line for releasably locking thereto one each of a plurality of rings moved along the line in time spaced successive order, each ring being locked only until the next succeeding ring has engaged the device, each of the rings having one portion thereof movable with respect to an adjacent portion whereby the rings may be assembled on the firing line singly in successive order and the two portions locked together after such assemblyfor slideable movement of the ring along the line. v V g V A still further object is the provision of a pair of firing lines towable from opposite sides of a vessel and having a pair of ring releasing members, each connected respec .tively to a trailing end of the lines, for releasinga ring scription taken in connection with the accompanying drawings on which like numerals of reference are employed to designate like or similar parts throughout the several views and in which:

Fig. 1 is a view in elevation of aseismic surveying system employing the device of the present invention in accordance with a preferred embodiment thereof;

Fig. 2 is a plan view of the system of Fig. 1;

Fig. 3 is a view in elevation and partially broken away of a ring having an explosive charge connected thereto locked to the ring locking and releasing device and towed by the firing line prior to exploding the charge;

Fig. 4 is a view similar to Fig. 3 on which is shown a ring being released from the locking member as the member is engaged by a succeeding ring;

Fig. 5 is a plan view greatly enlarged and partially broken away of one of the ring locking and releasing electrode members of Figs. 1 and 2;

Fig. 6 is a view taken along the line 6-6 of Fig. 5;

Fig. 7 is a view taken along the line 77 of Fig. 5;

Fig.8 is a view of a connecting member slideable along the firing line and suitable for use with the locking electrode member of Fig. 5 for establishing a towing and firing connection to the explosive charge;

Fig. 9 is a view of the connecting member of Fig. 8 according to an alternative form thereof;

Fig. 10 is a view taken along the line 1010 of Fig. 9 on which is shown means suitable for detachably locking together the movable portions of the ring member; and a Fig. 11 is a circuit diagram suitable for' applying a firing current selectively to the firing lines.

Referring now to the drawings for a more complete understanding of the invention and more particularly to Figs. 1 and 2 thereof, there is shown thereon a pair-of firing lines 11 carried by booms 12 secured to a towing vessel 13 on oposite sides thereof. A spread well suited for use with the present invention may comprise a plurality of pressure operated microphones disposed at intervals along a fluid filled'hose-like member '14, preferably thongh not necessarily, maintained at a predetermined depth of submersion by a strut 15 secured to the towing vessel, such, for example, as thespread. disclosed and claimed in Patent No. 2,465,696 to Le Roy C. Peaslay, issued March 29, 1949 for Method and Means for Surveying Geological Formations although, ifde- :sired, other spreads may be employed.

3 a ring retaining and releasing device generally indicated by the numeral 16 composed of a metal substantially 1mperviousto the deleterious action of sea Water such, for

j example, as aluminum or the like, the aluminum being preferably anodized to reduce electrical leakage therefrom to the surrounding water. The device comprises a body 17 of exterior cylindrical configuration having a smooth tapered portion 18 contiguous therewith at the forward end thereof forestablishing a smooth exterior contoured surface between the cylindrical portion of the device and a firingline 11. The line 11, it will be understood, comprises an electrical conductor 19 including at least one strain element disposed within a sleeve or jacket 21 composed of insulating material suitable for the. purpose possessing the desired qualities of flexibility, ruggedness and preferably of such density as to bring the specific gravity of the line to equality or. slightly less than the specific gravity of the surrounding water. It will be understood, however, that, if desired, the ring locking and releasing device of the present invention may be advantageously employed with'a firing line of greater specific gravity than that of the surrounding water.

' thereto, to a metallic cap or washer 24 in snug abutting relation with the trailing end surface of body 17 to establish an electrical and towing connection thereto, that portion of the conductor 19 within the body 17 being i drawn taut substantially as illustrated.

There is also provided within the trailing portion of the body 17 a third bore 25 with which the cap 24 is in registry and within which a bared length of conductor 19 is disposed. On opposite sides of the body are formed a pair of longitudinallydisposed slots 26 substantially as illustrated within which are arranged a pair of resilient rod-like locking members 27 for substantially radial sliding movement therein. Each member 27 s composed of resilient metal suitable for the purpose, such, for example, as stainless steel and threaded as at 28 for engagement with a tapped hole 29 within the body 17, rotative moveelectroconductive container or casing 37 containing a quantity of explosive material. The other connection to the detonator is connected as by conductor 38 to the casing 37.

On Fig. 9 is shown an alternative form of firing ring member designated generally by the numeral 39 comprising two arcuate portions 41 and 42 connected together for pivotal movement as at 43, to which is secured the ring or eye 34. At each outer end of the portions 41 and 42 is provided a catch 44 for mutual engagement to establish a locking connection therebetween when the portions 41 and 42 are brought together. The ring 39 may be employed interchangeably with ring 33 and possesses the additional advantage that by reason of the split construction thereof, additional rings with the charges attached thereto may be added at will to a firing line or I removed therefrom, if desired, without interrupting the towing operation.

A firing circuit suitable for use with thhe present invention is shown on Fig. 11 in which a firing current is applied to the firing lines 11 selectively by a switch 45, the closure of which establishes a circuit connection from the firing lines to a source of electrical energy such, for example, as the battery 46 illustrated. In the event that a sea water return from the casing 37 to the vessel is employed, the connection from switch 45 to one of the firing lines 11 would not be required and in lieu thereof the switch would be connected to the hull of the vessel or to a plate connected thereto and in communication with the water. Furthermore, in this latter arrangement, if desired, only a single-pole single-throw switch would be required I or the equivalent thereof to close the firing circuit.

' The operation of the system of Figs. 1 and 2 will now be described. Let is be assumed, by way of example,

that a copious quantity of firing rings with charges attached thereto are assembled on each of the firing lines 11 and carried by the vessel in readiness to be released in successive order from the vessel and that both of the firing lines are trailing within the water from the ends of the booms 12. Let it further be assumed that a ring 33 is released from the vessel on the starboard side. The

' ring travels along the line and the ring retaining and releasment of the member within the hole after assembly therewith being prevented by a set screw30, as shown.

The other end or bolt portion of each of the members 27 is formed substantially L-shaped at 31 and normally projects outwardly from the outer cylindrical surface of the body 17 to provide a retractible locking element for a ring-like member, slideable over the body, when the member is engaged by the L-shaped elements 31. The

L-shaped portion 31 of each of the locking members 27 is connected to the fixed threaded portion of the locking member by an arcuate length 32 extending at the central portion thereof outwardly beyond the outer cylindrical surface of the body 17 to such a degree that when moved inwardly by the ring-like member, a ring previously held by the L-shaped portion 31 of the locking member is released and detached therefrom.

On Fig. 8 is shown a ring member 33 having an aperture therein of sufficient size to slide freely along the firing line 11 and the cylindrical surface of body 17, there being just suflicient clearance between the inner diameter of the ring to insure free sliding movement along the body 17 and to operate the locking L-shaped portion 31 of the locking device to a release position concurrently therewith. There is secured to the ring member 33 in any suitable manner, as by welding or brazing the parts together, a second eye or ring 34 for establishing an electrical and towing connection as by the line 35 to an electroresponsive detonator 36, Fig. 3, disposed within an ing member until it passes over the arcuate portions 32 and is arrested by the projections 31 of the locking member, movement of the ring over arcuate portions 32 at this time being without'efiect for the reason that another ring is not locked by the L-shaped portions 31 connected thereto. When this occurs, the explosive charge is towed through the water by the starboard firing line secured to the moving vessel until it has reached a desired position at which time switch 45 is momentarily closed and a firing impulse is transmitted over the starboard firing line to explode the explosive charge, the circuit including the casing of the charge, a seawater path from the casing to the ring releasing mechanism of the port firing line and thence by way of the port firing line to the vessel.

A ring is now released from the port side of the vessel and travels along the port firing line until locked by the locking and releasing ring mechanism secured thereto, or, if desired, the ring may be released on the port firing line prior to exploding the charge on the starboard firing line. After the charge has been towed to a desired position, switch 44 is momentarily closed in a reverse direction to apply a firing impulse to the port firing line to explode the charge connected thereto, the firing circuit including a seawater path between the casing of the charge and the locking and releasing ring mechanism of the starboard firing'line, and thence by way of the starboard firing line to the vessel.

A ring is now held locked to each of the port and starboard ring releasing mechanisms with a short length of conductor 35 trailing therefrom.

The next shot is to be fired from the line connected to the starboard side of the vessel. To achieve this, a ring is released on the starboard firing line, if desired,

prior to firing the charge on port firing line, and as the ring moves along the starboard firing line by movement of the firing line through the water and engages the arcuate length 32, of the pair of flexible locking members 27, the end portions '31 thereof are withdrawn within the cylindrical casing of the ring retaining and releasing mechanism thereby releasing the first ring previously locked thereby. As the ring moves past the arcuate portion of the locking members, the L-shaped ends 31 thereof spring back to the initial locking position shown on Fig. 5 of the drawings thereby locking the second ring to the ring retaining and releasing device 16. The charge is fired :by a firing current applied to the star board firing line when the charge has been towed to the proper firing position. The charges, according to the operation of the preferred form of the system, are thus operated in alternate order on the two firing lines after being towed to a desired position, the firing ring remain ing locked to the ring locking and releasing mechanism until released by the next succeeding ring moving into engagement with the arcuate portion 32 of the ring releas ing members.

Although the system of Figs. 1 and 2 has been described with reference to two firing lines operable in alternate order, it will of course be understood that, if desired, only a single firing line may be employed and furthermore the ring releasing mechanism 16 of the other line may be replaced by a single electrode for establishing an electrical connection between the other line and the seawater thereby to provide a return path to the Vessel for the firing current applied to the first firing line.

The firing line of the present invention is also well suited for use with a system, if desired, in which the seawater path extends from the casing of the explosive charge to the hull of the vessel or to a plate secured thereto. Such an arrangement, however, is not preferred for the reason that the firing current flowing through the seawater is generally parallel to the length of the detection streamer or array throughout a substantial portion of the length thereof and thusmay adversely aifect the sensitive seismic detecting devices and circuits con nected thereto by electrical leakage through the water.

7 By employing two firing lines in the manner herein disclosed, the seawater path for the firing current is of relatively short length and is transverse to the length of the detection streamer or array and for this reason the leakage of firing current thereto is of such small proportions as to be negligible.

Without further analysis the foregoing will so fully r'evealthe gist of this invention that others can, by applying current knowledge, readily adapt it for various applications without omitting certain features'that, from the standpoint of the prior art, fairly constitute essential characteristics of the generic or specific aspects of the invention, and therefore such adaptations should and are intended to be comprehended within the meaning and range of equivalency of the following claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a surveying system for seismic exploration of submerged areas from a vessel, the combination of a firing line towed by the vessel and having an electrode exposed to the surrounding water near the trailing end thereof of generally cylindrical configuration, said electrode having a pair of diametrically disposed slots therein, a pair of resilient locking members secured to said electrode and movable within said slots from an initial locking position to a release position, said locking members each having a movable end portion and an arcuate central portion normally extending outwardly from the cylindrical contour of the electrode for moving the locking member to said release position as the central portion is moved inwardly from an initial position to sub stantial coincidence with the cylindrical surface of the electrode, a metallic contact member encircling said electrode and having an annular surface therein for slideably engaging the arcuate portions of said locking members sulficiently to move the locking members momentarily to said release position as the contact member slides along said electrode, and a pair of substantially L-shaped projections on the movable end portions of said locking members for locking said contact member thereto when the locking members have been moved to said release position whereby the contact member remains locked by said L-shaped projections until the arcuate portions of said locking members are moved to said release position by a second contact member moving into operative engagement therewith as the second contact member slides along saidelectrode.

2. The combination of claim 1 including a casing having an explosive charge and an electrore'sponsive detona- -tor disposed therein, means electrically connecting the said source of current, an elongated metallic electrode secured to the trailing end portion of said line in electrical connection with said conductor, a contact membcr constructed and arranged toslide easily along said jacket and said electrode, means for releasably locking the contact member to the trailing end portion of said electrode in electrical circuit with said conductor, a second contact member slideable along said electrode, and means on the electrode engageable by said second contact member for unlocking the first named contact member and immediately thereafter locking the second contact member to the electrode.

5. The combination of claim 4 including a line connected to each of said contact members respectively, a casing connected to said last named line and having an explosive charge disposed therein, and means within the casing electrically connected to said last named line for firing said charge by a firing current received over said firing line while the contact member connected thereto is locked to said electrode.

6. In a system for seismic prospecting of submerged areas from a vessel, in combination, a firing line disposed within the sea water and adapted to be towed by the vessel, an elongated contact .member connected to the trailing end portion of said line, a plurality of metallic contact elements slidable in successive order on said line and contact member, a plurality of containers each having an explosive charge therein, an, electroresponsive detonator disposed within each of said containers for firing said charge, means electrically connecting said detonator to said contact element, said last named means forming a towing connection to the container, means for locking a first one of said'contact elements to the elongated contact member until the explosive charge connected thereto has been towed by the firing line and said towing connection to a desired position within the water and fired by a firing impulse received over the firing line,and means on said elongated contact member actuated by the next succeeding contact element during sliding movement thereof along the contact member for unlocking the first named contact element and locking said next succeeding element to the contact member in lieu thereof.

7. The combination of claim 6 in which the locking means comprises a pair of diametrically disposed resilient locking elements each secured at one end thereof interiorly to said elongated contact member and having a bolt portion formed on the opposite end thereofand movable from an initial locking position selectively to a release position, actuating means on each of said locking elements for moving the bolt portions thereof to said release position as the actuating means are engaged by said contact element during sliding movement thereof among said elongated contact member.

8. The combination of claim 7 in which the means for moving the bolt portions to said release position are so arranged that the contact element is disengaged therefrom during said sliding movement in sufiicient time for each of the bolt portions to be moved to the locking position thereof and lock the contact element thereto during continued sliding movement of the contact element along the elongated contact member.

9. In a system for seismic surveying of submerged areas from a vessel, the combination of a firing line towed by the vessel and having an elongated electrode connected near the trailing end portion thereof, a pair of resilient stop members carried by said electrode and movable from an initial stop position to a release position, an annular contact member slideable on said firing line and electrode of such configuration as to be stopped and locked by said stop members when the stop members are in said stop position, a casing having an explosive charge therein connected to said annular member and adapted to be towed through the Water by the moving vessel when the annular member is locked by said stop members, and means on said stop members operable by a second annular member moving into engagement therewith for momentarily actuating the stop members to said release position thereby to release the first named annular member and lock the second annular member thereto.

10. The combination of claim 9 in which said annular members each comprises a pair of complementary arcuate portions pivotally connected together and movable at will to an open position, and means on said members for locking the members together when the members have been moved to closed position.

11. The combination of claim 9 including an electroresponsive detonator disposed within said casing for firing the explosive charge, each of said annular members having an eye secured thereto, and an electrical conducting line connected to said eye and to said detonator for establishing a towing connection to said casing and a firing circuit to the detonator when the annular member is locked to said electrode.

12. The combination of claim ll including means on the vessel for applying a firing current to said firing line of suflicient strength to actuate said detonator and fire the charge while the annular member is locked to said electrode.

13. In a system for seismic surveying of submerged areas from a vessel, the combination of a pair of firing lines connected to opposite sides of the vessel respectively and towed through the Water thereby, said firing lines each being of substantially the same length and having a smooth waterproof jacket thereon, a pair of elongated electrodes respectively connected near the trailing end of the firing lines, each of the electrodes having an outer smooth cylindrical configuration of greater diameter than the jacket and a tapered portion forming a smooth continuous contour therewith, a strain conductor arranged within each of said firing lines and the electrode connected thereto, means for connecting the trailing end portion of said strain conductor to the trailing end of the electrode in a manner to effect an electrical and towing connection therewith, a axial bore within the forward end portion of the electrode for receiving an end portion of said jacket in snug fitting engagement therewith, a second axial bore within the trailing portion of said electrode, a pair of longitudinally arranged slots diametrically disposed on opposite sides of the electrode interconnecting said second bore with the cylindrical surface thereof, a pair of resilient metallic rods secured at the forward end thereof to an interior portion of the electrode and extending rearwardly for slideable movement within said slots, each rod having a convexly curved portion normally extending outwardly from the cylindrical surface of the electrode and an L- shaped locking portion formed on the trailing end thereof and movable from an outwardly projecting locking position to a retracted release position as the curved portion is moved inwardly from the initial outwardly extending position thereof, a plurality of annular connectors assembled on the firing lines and carried by the vessel, each connector having a casing filled with an explosive charge connected thereto, said connectors having an aperture therein of sufficient size to allow free sliding movement along said jacket and electrode when the connector and casing have been launched from the vessel and to engage the curved portions of the rods sufiiciently to move the L-shaped locking portions thereof momentarily to said release position, said locking portions returning to said locking position prior to movement of the connector to a position in locking engagement therewith whereby the connector is locked by said rods until the L-shaped portions are moved to a release position by engagement of the curved portions with another connector subsequently launched from the vessel, and means including a firing switch on the vessel for applying a firing current to the firing line while the connector is locked to the electrode thereby to actuate said detonator and fire the explosive charge.

14. The combination of claim 13 in which the casing is composed of electrical conducting material and the detonator is connected electrically to said connector and to the casing whereby the firing current flows in a circuit including a sea water path between said casing and the electrode of the other firing line and the conductor within the other firing line as the firing switch is closed.

15. The combination of claim 14 in which the firing switch is operable to each of two firing positions and connected to the firing lines in a manner to apply a firing current in either direction to the lines selectively at will in accordance with the firing position to which the switch is operated.

16. In a system for seismic prospecting of submerged areas, the combination of a firing line towed by a vessel, an elongated electrode device secured near the trailing end portion of said line, a metallic ring slideable along said line and electrode device and having a casing containing an explosive charge connected thereto, an electroresponsive detonator in electrical connection with said ring and disposed within said casing for firing said charge, means for locking said ring to the electrode device to establish a towing and electrical connection to said casing and detonator respectively, and means on said electrode device actuated only by the next succeeding ring having a second explosive charge connected thereto sliding into engagement therewith for actuating the locking means to a release position to release the first named ring after the charge connected to the first named ring has been fired by said detonator in response to a firing impulse received from the firing line while the first named ring is locked to the electrode device.

17. The combination of claim 16 in which the ring releasing means is constructed and arranged in such manner that the locking means is actuated to a release position by said next succeeding ring only for a period of time sufficient to release the first named ring and restored to an initial locking position for locking engagement with said next succeeding ring during sliding movement of the last named ring along said electrode.

2,324,378 Flude July 13, 1943

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