ARRANGEMENT FOR EVACUATING PEOPLE FROM AN OFFSHORE INSTALLATION

Abstract

An arrangement for evacuating people from an offshore installation having a lifeboat and an arrangement for a free-fall based lifeboat launch with a tilted ramp characterised in that the ramp of the free-fall launching arrangement is mounted on the ramp axle, has a wire rope winch and is movable. The power hydraulic mechanism of the ramp consists of an arrangement of the two lower and upper identical hydraulic cylinders, a gear bar, a gearwheel of the ramp axle and the additional gearwheel of the gear bar. Piston rods of hydraulic cylinders are arranged on two opposite sides of the gear bar and are connected to the ends of the gear bar. The gear bar engages with the additional gearwheel engaging with the gearwheel of the ramp axle.

Claims

1. An arrangement for evacuating people from an offshore installation having a lifeboat and an arrangement for a free-fall based lifeboat launch with a tilted moveable ramp, characterised in that the ramp (2) of the lifeboat launching arrangement has a ramp axle (13) and a wire rope winch (4); and the lifeboat launching arrangement has a power hydraulic mechanism of the ramp (2), which consists of an arrangement of two identical lower (5) and upper (6) hydraulic cylinders, having piston rods (9, 10), a gear bar (11), a gearwheel (12) of the ramp axle (13) and an additional gearwheel (14), wherein the piston rods (9 10) are arranged on two opposite sides of the gear bar (11) and the piston rods (9, 10) are connected to the ends of the gear bar (11), and the gear bar (11) engages with the additional gearwheel (14) engaging with the gearwheel (12) of the ramp axle (13).

2. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The invention is illustrated in the embodiment in the drawing in axonometric view, where

[0011] FIG. 1 is a side view of the entire lifeboat launching arrangement corresponding to the situation while the lifeboat is ready for launching,

[0012] FIG. 2 is a side view of the ramp lowering mechanism corresponding to the situation while the ramp is fully raised,

[0013] FIG. 3 is a side view of the ramp lowering mechanism corresponding to the situation while the ramp is fully lowered.

DETAILED DESCRIPTION

[0014] The embodiment of the invention shows a launching arrangement of a lifeboat 1 with a movable ramp 2 mounted on the ramp axle 13 and wire ropes 7 of the ramp winch 4, which allows for lowering it from under the lifeboat 1. The ramp 2 enables the lifeboat 1 to be launched by free fall, and the possibility of gravitationally lowering the ramp 2 from under the lifeboat 1 allows the lifeboat 1 to be launched gravitationally by fall of a lifeboat winch 3.

[0015] By using the method of suspending the lifeboat 1 onto wire ropes 18 of the lifeboat winch 3 described in U.S. Pat. No. 9,902,470, the second method of launching the lifeboat 1 by fall of the lifeboat winch 3 of the described arrangement complies with the requirements and standards for this arrangement.

[0016] Lowering the ramp 2 consists in using the simultaneous effect of the power hydraulic mechanism and of the ramp winch 4. The power hydraulic mechanism consists of two identical hydraulic cylinders 5 and 6, gear bar 11 and two gearwheels 12 and 14. The piston rods 9 and 10 of the hydraulic cylinders 5 and 6 are connected to the ends of the gear bar 11, which interacts with the gearwheel 12 of the ramp axle 13 through an additional identical gearwheel 14 which allows for converting the linear movement of the piston rods 9 and 10 of the cylinders 5 and 6 into a rotational movement of the ramp axle 13. The two wire ropes 7 of the ramp winch 4 are connected to the ramp 2 through rotatable links 8.

[0017] The ramp 2 is lowered by releasing the brake of the ramp winch 4. The brake of the ramp winch 4 can be released directly from the location of the ramp winch 4 or indirectly from the inside of the lifeboat 1, which allows for stopping the lowering of the ramp 2 at any time.

[0018] During the lowering the ramp 2, after the brake of the ramp winch 4 is released, the oil of the lower hydraulic cylinder 5 is pressed into the upper hydraulic cylinder 6 due to the effect of the weight of the ramp 2 on the extended piston rod 9 of the lower hydraulic cylinder 5 through the arrangement of the two gearwheels 12 and 14 and the gear bar 11. The possibility of using a control system for the oil flow rate from the lower hydraulic cylinder 5 to the upper hydraulic cylinder 6 allows for designating the speed of movement of the piston rods 9 and 10 of the hydraulic cylinders 5 and 6 and for determining a safe lowering speed of the ramp 2,

[0019] The ramp 2 is raised by the ramp winch 4 pulling the wire ropes 7. The ramp 2 is raised up to the initial position determined by the limit switch 15 of the power supply of the ramp winch 4. The limit switch 15 cuts off the power supply of the ramp winch 4 when the piston rod 10 of the upper cylinder 6 is fully inserted.

[0020] The lifeboat 1 is ready to be launched when on the ramp 2, its outer deck 28 is supported on the horizontal rollers 24 of the ramp 2, the chains 19 of the spreader 20 are pulled and the chain 22 which serves to keep the lifeboat 1 is in its initial position on the ramp 2 is tightened. The lifeboat 1 may be embarked by platform 23.

[0021] The launching of the lifeboat 1 by free fall consists in opening the hooks 17 and removing the chains 19 of the spreader 20 therefrom, and then releasing the chain 22 holding the lifeboat 1 on the ramp 2 by opening the aft hook 21. This results in the lifeboat 1 descending on horizontal rollers 24 from the ramp 2 and free falling into the water. The vertical rollers 25 of the ramp 2 stabilize the descent of the lifeboat 1 from the ramp 2.

[0022] The gravitational launching of the lifeboat 1 by fall of the lifeboat winch 3 consists in releasing the chain 22 holding the lifeboat 1 on the ramp 2 from the aft hook 21 of the lifeboat 1, lowering the ramp 2 from under the lifeboat 1 and lowering the lifeboat 1 into the water and releasing the chains 19 of the spreader 20 from the hooks 17 of the lifeboat 1. The hooks 17 are part of the lifeboat suspension system on the wire ropes 18 of the lifeboat winch 3 using triangular frames 16 arranged on both sides of the lifeboat 1.

[0023] The lifeboat 1 is lowered into the water by releasing the brake of the lifeboat winch 3. The brake of the lifeboat winch 3 can be released directly from the location of the lifeboat winch 3 or indirectly from the inside of the lifeboat 1, which allows for stopping the lowering of the lifeboat 1 at any time.

[0024] Lifting the lifeboat 1 out of the water and placing the lifeboat 1 on the ramp 2 in position ready for launching is done by using the lifeboat winch 3 to hoist the lifeboat 1 to the initial height and the ramp winch 4 to raise the ramp 2 to the initial height.

[0025] After connecting the chains 19 of the spreader 20 to the hooks 17 of the lifeboat 1, the lifeboat 1 can be hoisted to the initial height by using the limit switch system to cut off the power supply of the lifeboat winch 3.

[0026] The lifeboat 1 is placed on the ramp 2 in position ready for launching after the ramp 2 is raised to the initial position by the ramp winch 4 and using the turnbuckle 26 of the chain 22, which is connected to the fixed element 27 of the structure of the ramp 2, which allows for adjusting how tightened it is.

LIST OF COMPONENTS OF THE EMBODIMENT

[0027] 1lifeboat [0028] 2ramp [0029] 3lifeboat winch [0030] 4ramp winch [0031] 5lower hydraulic cylinder [0032] 6upper hydraulic cylinder [0033] 7wire rope of the ramp winch [0034] 8rotatable link of the ramp with the wire rope of the ramp winch [0035] 9piston rod of the lower hydraulic cylinder [0036] 10piston rod of the upper hydraulic cylinder [0037] 11gear bar [0038] 12gearwheel of the ramp axle [0039] 13ramp axle [0040] 11additional gearwheel [0041] 15limit switch of the ramp winch [0042] 16triangular frame of the suspension system of the lifeboat [0043] 17frame hook of the mechanism releasing the lifeboat of the launching arrangement by falls [0044] 18wire rope of the lifeboat winch [0045] 19chain of the spreader [0046] 20spreader [0047] 21aft hook of the mechanism releasing the lifeboat of the launching arrangement by free fall [0048] 22chain of the aft hook [0049] 23lifeboat embarkation platform [0050] 24horizontal rollers of the ramp [0051] 25vertical rollers of the ramp [0052] 26turnbuckle of the aft hook chain [0053] 27fixed element of the ramp structure [0054] 28outer deck of the lifeboat