US3351036A - Jettison system for discharging fluid from a ship at sea - Google Patents

Description

17967- .A. D. PAOLI 3,351,036

JETTISON SYSTEM FOR DISCHARGING FLUID FROM A SHIP AT SEA Filed March 18, 1966 2 Sheets-Sheet 1 ATTORNEY Nov. 7, 1967 A. D. PAOLI 3,

JETTISON SYSTEM FOR DISCHARGING FLUID FROM A SHIP AT SEA Filed March 18, 1966 2 Sheets-Sheet 2 INVENTOIR fiLEXA/vQE/KDHA 2404 ATTORNEY 3,351,036 JETTISON SYSTEM FOR DISCHARGING FLUID FROM A SHIP AT SEA Alexander Delli Paoli, Huntington Station, N.Y., assignor to Esso Research and Engineering Company, a corporation of Delaware Filed Mar. 18, 1966, Ser. No. 535,513 4 Claims. (Cl. 114-183) ABSTRACT OF THE DISCLOSURE A retractable framework at the stern of a ship is movable to place the end of a liquid cargo jettison conduit below the level of the sea water. A foil section carried by the framework provides downward thrust on the jettison conduit framework to maintain its discharge below the sea water. Pulley and lifting strut mechanism are employed for raising and lowering the framework.

The present invention relates to jettison systems.

In particular, the present invention relates to jettison systems adapted to be used for discharging fluids from a ship at sea.

The structure of the invention is intended primarily to be used by a tanker carrying a fluid which may create dangerous conditions if the fluid escapes from a cargo tank while the tanker is at sea. Such a fluid may be, for example, liquefied natural gas, hereinafter referred to as LNG. It is customary to transport LNG in the form of a liquid. In order to maintain the LNG in liquid form at atmospheric pressure, the temperature of the LNG must be lowered to 259 F. Of course, the cargo tank itself has a storage capable of withstanding such low temperatures. However, the ships hull is made of ordinary carbon steel which would embrittle and fracture at 259 F., so that if it should happen that any of the LNG leaks from a cargo tank, it is necessary for safety purposes to pump the LNG overboard when such a leak is detected.

It is, therefore, a primary object of the invention to provide, as a safety device for a tanker, a jettison system capable of discharging a fiuid such as LNG, or, in fact, any other dangerous fluid.

In particular, it is an object of the invention to provide a jettison system of this type which can quickly and easily be displaced from a stowed position to an operative position where discharge of the fluid will quickly and efliciently be carried out.

Furthermore, it is an object of the invention to provide a jettison system whose parts are quite simple while at the same time capable of operating very reliably to place the system either in its stowed or in its operative position.

Also, it is an object of the invention to provide a jettison system which takes advantage of such factors as the thrust derived from the discharging fluid and the motion of the ship with respect to the sea so as to tend to reliably maintain the parts in their operative position while the ship remains under Way.

The jettison system of the invention includes a conduit means which communicates with the fluid which may have to be discharged at sea. This conduit means has an exterior portion situated at the exterior of the ship and terminating in a discharge nozzle. A mounting means of the invention mounts the exterior portion of the conduit means for movement between an upper, inoperative stowed position and a lower, operative discharge position Where the fluid is discharged through the conduit means and out through the discharge nozzle to the sea.

The invention is illustrated by way of example in the accompanying drawings which form part of the application and in which:

I United States Patent Ofifice 3,351,936 Patented Nov. 7, 1967 FIGURE 1 fragmentarily and schematically illustrates the side view of the stern of a ship carrying the jettison system of the invention in the stowed, inoperative position in solid lines and in the operative position in dotdash lines;

FIGURE 2 is an elevation view of the jettison system of the invention as it appears when looking forward toward the stern of the ship, the system being shown in its stowed position in FIGURE 2;

FIGURE 3 is a side elevation, partly in section, of the structure of FIGURE 2 taken along line 3-3 of FIGURE 2 in the direction of the arrows, with part of the structure broken away in FIGURE 3 so as to more clearly illustrate the details of the structure;

FIGURE 4 is a fragmentary sectional side view of a mounting bracket and the parts carried thereby;

FIGURE 5 is a fragmentary partly sectional top plan view taken along line 5--5 of FIGURE 3 in the direction of the arrows and showing the parts in their stowed position;

FIGURE 6 is a top plan view taken along line 6-6 of FIGURE 4 in the direction of the arrows and showing the parts in their operative position; and

FIGURE 7 is a perspective illustration of one of the mounting brackets of the jettison system of the invention.

Referring now to FIGURE 1, the transom 10 of a ship 12 is fragmentarily and schematically illustrated. A conduit means 14 communicates with a cargo tank which carries the fluid, such as LNG, which may have to be discharged while the ship 12 is under way, in the event that a leak from the cargo tank is detected. The conduit means 14 has an exterior portion made up of a stationary tubular part 16 and a movable tubular part 18. As is shown most clearly in FIGURE 2, the stationary tubular part 16, in the form of a suitable pipe or hose, is fixed directly to the transom or stern 10 by suitable clips 20. A fluid tight swivel joint 22 of conventional construction is also fixed to the stern 10, and the stationary tubular part 116 communicates with the swivel joint 20. The movable tubular part 18 of the conduit means 14 also communicates with the swivel joint 20, so that the movable tubular part 18 can turn with respect to the stationary part 16 of the conduit means about the axis provided by the swivel joint 22.

The end portion of the conduit means 14 terminates in a discharge nozzle 24 which is curved at the end of the tubular part 18 so as to direct the discharging fluid in a given direction for a purpose described below. It will be understood that the parts 16, 18, and 24 may be provided with a suitable exterior insulation to prevent excessive buildup of ice thereabout during LNG discharge.

A mounting means mounts the conduit means 18 for movement between the stowed position shown in solid lines in FIGURE 1 and the operative position shown in dot-dash lines in FIGURE 1. In its lower operative position, the discharge nozzle 24 is situated at an elevation preferably no higher than the waterline. In FIGURE 1 the discharge nozzle 24 is shown in dot-dash lines slightly below thewaterline, so that when the fluid is pumped out through the conduit means 14 it will discharge away from the stem 10 providing at the discharge nozzle 24 a thrust of the discharge nozzle 24 toward the stem 10. In this way the parts will tend to be maintained in their operative position due to their own weight and the nozzle thrust, as will be apparent more clearly from the description below.

The mounting means of the invention is formed by the structure shown in FIGURE 2 carrying the movable part 18 of the conduit means. This structure includes a pivot support means formed by a pair of brackets 24a and 24b, and a frame means 26 formed by an A-frarne 28 which directly carries the movable conduit portion 18.

The support means supports the frame means 26 for movement between the upper stowed position, shown in solid lines in FIGURE 1, and the lower operative position shown in dot-dash lines in FIGURE 1. A cable 30 is connected to the A-frame 28 and forms a moving means for moving the frame means 26 with respect to the support means between the lower operative position and the upper stowed position. This cable 30 is connected to a suitable winch (not shown) which can be operated to pay the cable out so as to lower the frame means 26 to its operative position or to wind the cable up so as to return the frame means 26 to its stowed position.

The jettison system also includes, in the illustrated example, a lifting strut 32 which is substantially coextensive with the A-frame 28, as is apparent from FIG- URE 2. This lifting strut 32 carries a pulley 34 around which the cable 30 is guided so that efiicient raising of the frame means 26 will be provided. As will also be apparent, the operation of strut 32 also prevents any possibility of toggling of the A-frame 28 when it is raised from the operative to the stowed position.

The pair of brackets 24a and 24b respectively have walls 36a and 36b which are directly fixed to the hull of the ship at its stern It). The bracket 24a has a pair of outer webs 38a and an intermediate web 40a situated between and equidistantly spaced from the outer webs. All of these webs are integral with and extend from the wall 36a of the bracket 24a. In the same way the bracket 36b has a pair of outer webs 38b and an intermediate web 40b situated substantially midway between the outer webs 38b. These webs are all parallel to each other and are situated in substantially vertical planes. The webs of the bracket 24a carry a pivot 42a in the form of a suitable horizontal pivot pin extending through suitable coaxial bores of the webs 38a and 40a. In the same way the webs of the bracket 24b carry a pivot 42b.

The A-frame 28 terminates in a pair of free ends 4411 and 44b through which the pivots 42a and 42b respectively extend, and these ends 44a and 44b of the A-frame are situated between the intermediate webs Mia and 46b, on the one hand, and the outermost webs 38a and 381), on the other hand. The turning axis defined by the coaxial pivots 42a and 42b coincides with the turning axis provided by the fluid-tight swivel joint 22, so that the movable tubular part 18 will turn about the same axis as the A-frame 28. The A-frarne includes a rigid crossbar 46 fixedly carrying a tubular clip 47 (FIG- URE 3) by which the tubular part 18 is directly fixed to and carried by the A-frame 28 for movement therewith.

At the extremities of its free ends 44a and 44b, the A-frame 28 fixedly carries a pair of fingers 48 which extend behind the lifting strut 32 for a purpose described below. These fingers may be formed integrally with the A-frame. FIGURES 3, 5, and 6 show the finger 48 which is fixed to the end 44b of the A-frame. This finger 48 is of a substantially L-shaped configuration and extends through a notch 56 (FIGURE 3) of the intermediate web 4% into the space behind the lower right end of the strut 32, as viewed in FIGURE 2. In the same way, the left end 44a of the A-frame 28, as viewed in FIGURE 2, carries a finger which is in all respects symmetrical with the finger 48 and which extends behind the left lower end of the strut 32, as viewed in FIGURE 2.

The lower ends of the strut 32 extend between the innermost pair of webs 38a and 38b, on the one hand, and the intermediate webs 40a and 40/5, on the other hand, and the pivots 42a and 42b extend through aligned bores at the free ends of the strut 32, so that in this way the strut 32 is also supported for rotary movement about the same axis as the A-frame 28 and the tubular part 18. At its outer end which is distant from the brackets 24a and 24b, the strut 32 carries a pivot on which the pulley 34 is supported for free rotary movement in the manner shown most clearly in FIGURE 2. The cable 30 is fixed at one end to the crossbar 46 and extends from the latter over the pulley 34 and to the unillustrated winch.

The support means formed by the brackets 24a and 24b is provided with stops which include frame stops to be engaged by the A-frame and strut stops to be engaged by the strut, so as to fix the lowermost operative positions of the frame 28 and the strut 32. For this purpose the bracket 24a fixedly carries between the outermost web 38a and the intermediate web 40a a stop 5211 having a downwardly and rearwardly inclined stop surface to be engaged by the end 44a of the frame 28. The bracket 24]) has an identical stop 52b shown also in FIGURES 3, 4, and 7. This stop is fixed by any suitable web to the wall 36b.

Between the innermost webs 38a and 3812, on the one hand, and the intermediate webs 40a and 40b, on the other hand, the brackets 24a and 24b respectively carry a pair of strut stops 54a and 54b which have upwardly directed substantially horizontal stop surfaces. Actually, as is apparent from FIGURES 3, 4, and 7, the stop surfaces of the strut stops are inclined slightly downwardly toward the stern of the ship. These strut stops are also fixed by suitable webs to the walls 36a and 36b of the brackets, respectively.

The above-described jettison system operates as follows:

In the stowed position the frame means 26 has the inclination indicated in solid lines in FIGURE 1. Therefore, its center of gravity is situated somewhat to the left of its turning axis, as viewed in FIGURE 1. The frame means 26 is maintained in this stowed position by the tension of the cable 30 when it is fully wound onto the winch. Therefore, when it becomes necessary to discharge fluid, the winch is operated to pay out the cable 30, and the frame means 26 will simply move downwardly about the pivot axis defined by the pivots 42a and 42b due to the weight of the frame means 26. The tubular part 18 of the conduit means 14 will of course turn about the same axis together with the A-frame 28. The cable 30 is paid out until the A-frame engages the stops 52a and 52b which situate the A-frame in the dot-dash line position indicated in FIGURE 1.

During the initial part of the downward turning of the frame means 26, the fingers 48 at the extremities of the free ends 44a and 44b approach the lifting strut 32, and then they engage the latter so that after the A-frame has started to turn toward its lower operative position the lifting strut 32 is constrained to turn therewith, and in this way the lifting strut 32 reaches the dot-dash line position shown in FIGURE 1. In this latter operative position of the lifting strut it engages and presses against the stops 54a and 54b. In its operative position the lifting strut 32 extends outwardly away from the stern 10 in a substantially horizontal direction so that the cable 30 will extend in the direction shown in dot-dash lines in FIG- URE 1. In this way when the frame means 26 is returned to its stowed position the pull on the cable will extend substantially perpendicularly to the plane in which the frame means 26 is located, so that an eificient pulling force is provided in this way and toggling is prevented.

When the parts have reached their operative position the fluid is pumped out through the conduit means 14. It will be noted that as the fluid discharges from the discharge nozzle 24 a thrust may occur urging the frame means 26 against the stops 52a and 52b, and this force is transmitted through the fingers of the A-frame to the lifting strut 32 which is thus also pressed against the strut stops 54a and'54b.

I11 order to assure that the fluid is discharged from the nozzle 24 in a submerged condition, the A-frame 28 fixedly carries at its outer tip a horizontally extending foil 6t? which becomes situated beneath the waterline, as indicated in FIGURE 1. The surface angle of the foil 60 is such that due to the movement of the ship 12 the sea water flowing over the foil will also urge the frame means 26 downwardly against the stops 52a and 52b. Through these expedients, namely the flow of Water over the upper foil surface and the thrust created by the discharging fluid, the frame 28 is held down hard against its stops and is kept from oscillating. At the same time this force is transmitted through the fingers of the A-frame to the lifting strut to maintain the latter without oscillation in its extended position pressing against the stops 54a and 54b.

The lifting strut is desirable in those instances where the angle between the stowed and operating positions of the A-frame approximates 180. In other cases where the angle through which the A-frame moves is substantially less than 180 a lifting strut may not be required. The lifting strut will provide reasonable lifting forces by way of the cable 30 and will eliminate any tendency to toggle or bind.

It is to be noted that the elevation of the turning axis of the A-frame is well above the waterline so that when the frame is in its stowed position it will be at an elevation substantially higher than the waterline. On the other hand, in the operative position of the parts the nozzle 24 is situated preferably somewhat beneath the waterline so as to discharge the fluid directly into the sea water. If desired, the tubular par-t 18 can be extended so that the nozzle 24 is situated out beyond the tip of the A-frame.

When discharge of the fluid has been completed the cable 30 is rewound onto the winch and the parts will then return to the stowed position shown in solid lines in FIGURE 1.

The parts can be designed to discharge the fluid at the waterline, but it is preferred to provide for the discharge nozzle, in its operating position, an elevation no higher than the waterline and preferably an elevation somewhat below the waterline.

The jettison system described above is suitable for installation on any type of ship stern. It does, however, adapt itself more readily to a transom type stern so that protuberances beyond the hull of the ship are minimized, thereby affording a greater measure of protection for the device. It is furthermore feasible to provide transom type ships with a recess for situating the jettison system of the invention within a cavity built into the transom. For the sake of appearance, a cover plate can be provided and fitted on the A-frame 28.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. For use with a ship carrying a fluid which may have to be discharged at sea, a jettison system comprising a pair of exterior brackets adapted to be fixed to the ship at the exterior thereof, a pair of pivots carried by said brackets and having a common substantially horizontal axis, an A-frame having a pair of free ends turn- 6 ably mounted on said pivots, so that said A-frame is swingable about said pivots from an upper stowed position where said A-frame extends upwardly from said axis to a lower operative position where said A-frame extends at least up to the waterline, said brackets respectively carrying frame stops engaged by said A-f-rame when the latter is in said lower operative position thereof to determine the lower position of said A-frame, a cable connected to said A-frame for turning the latter between said positions thereof, discharge conduit means communicating with the fluid and having an exterior portion carried by said A-frame for movement therewith and terminating in a discharge nozzle which is situated at an elevation no higher than the waterline when said A-frame is in said lower operative position thereof and foil means secured to said A-frame arranged to be situated beneath the waterline when said A-frame is in said operative position thereof and deriving from the movement of the ship a force acting on said A-frame to urge the latter against said frame stops.

2. A system as recited in claim 1 and wherein said discharge conduit means further includes a stationary tubular part carried by the ship at its exterior, and a swivel joint fluid-tightly interconnecting said stationary tubular part and said exterior portion, said swivel joint having an axis coinciding with the turning axis of said A-frame means.

3. A system as recited in claim 1 and wherein a lifting strut carries a pulley which guides said cable, said lifting strut having a pair of free ends also piv-otally carried by said pivots so as to be turnable about the same axis as said A-frame, and said lifting strut being substantially coextensive with said A-frame, said brackets respectively carrying strut stops which engage said strut to limit the latter to movement from a stowed position to an operative position where said strut is situated at an elevation higher than said A-frame when the latter is in said lower operative position thereof, with said strut extending outwardly away from the ship to provide for the cable a direction which will produce eflicient movement of the A-frame, said A-frame having fingers which respectively engage said strut during lowering of said A-frame to said operative position thereof for turning said strut to said operating position thereof in response to lowering of said A- frame.

4. A system as recited in claim 3 and wherein said brackets and all of the structure carried thereby are situated at the stern of the ship.

References Cited UNITED STATES PATENTS 2,798,364 7/ 1957 Morrison 1l474 2,914,080 11/1959 Silveston 141-388 3,040,469 6/1962 Richards 114-485 3,047,016 7/ 1962 Andresen 137615 FOREIGN PATENTS 278,601 10/1927 Great Britain.

MILTON BUCHLER, Primary Examiner. ANDREW H. FARRELL, Examiner.

Claims (1)

1. FOR USE WITH A SHIP CARRYING A FLUID WHICH MAY HAVE TO BE DISCHARGED AT SEA, A JETTISON SYSTEM COMPRISING A PAIR OF EXTERIOR BRACKETS ADAPTED TO BE FIXED TO THE SHIP AT THE EXTERIOR THEREOF, A PAIR OF PIVOTS CARRIED BY SAID BRACKETS AND HAVING A COMMON SUBSTANTIALLY HORIZONTAL AXIS, AN A-FRAME HAVING A PAIR OF FREE ENDS TURNABLY MOUNTED ON SAID PIVOTS, SO THAT SAID A-FRAME IS SWINGABLE ABOUT SAID PIVOTS FROM AN UPPER STOWED POSITION WHERE SAID A-FRAME EXTENDS UPWARDLY FROM SAID AXIS TO A LOWER OPERATIVE POSITION WHERE SAID A-FRAME EXTENDS AT LEAST UP TO THE WATERLINE, SAID BRACKETS RESPECTIVELY CARRYING FRAME STOPS ENGAGED BY SAID A-FRAME WHEN THE LATTER IS IN SAID LOWER OPERATIVE POSITION THEREOF TO DETERMINE THE LOWER POSITION OF SAID A-FRAME, A CABLE CONNECTED TO SAID A-FRAME FOR TURNING THE LATTER BETWEEN SAID POSITIONS THEREOF, DISCHARGE CONDUIT MEANS COMMUNICATING WITH THE FLUID AND HAVING AN EXTERIOR PORTION CARRIED BY SAID A-FRAME FOR MOVEMENT THEREWITH AND TERMINATING IN A DISCHARGE NOZZLE WHICH IS SITUATED AT AN ELEVATION NO HIGHER THAN THE WATERLINE WHEN SAID A-FRAME

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