Note: Descriptions are shown in the official language in which they were submitted.
CA 02237999 1998-OS-19
WO 9'7/22514 PCTIGB96103083
1
MARTNE ESCAPE SYSTEMS
The invention relates to marine escape systems_
S A marine escape system is used for evacuating people from a
structure at sea in the event of an emergency. Such a
structure may be an oil rig or a ship.
One form of marine escape system includes liferafts into which
the people are evacuated. Since, when liferafts are deployed
on water, there is usually a significant difference in height
(freeboard) between the point on the structure from which the
people are evacuated and the liferafts, it is necessary to
provide some form of passage between the two.
It is known to provide an angled chute, which may be formed
from inflatable members, extending between the evacuation
point and the liferafts. The chute can extend either direct
to the liferafts or to an inflatable floating structure to
which the liferafts are attached. In some vessels, the
freeboard may be 14-15 metres and so the chute is of
significant length.
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Recent sinkings of ships have placed greater emphasis on the
need to evacuate marine structures quickly in the event of an
emergency. It is likely to be a requirement that any sea-
going vessel must be able to evacuate 400 people in 17 minutes
40 seconds. In addition, it is likely to be a requirement
that any marine escape system must be able to operate in force
six weather which will include a 3 metre swell and that the
marine escape system must be usable for a considerable period
of time with the vessel side-on to the sea.
An angled chute a.s not readily able to meet such a
requirement. Since the chute projects from the side of a
vessel it requires stabilization in order to prevent
significant lateral movements in heavy weather. Further, to.
accommodate such weather, the chute must be comparatively
rigid and this can incre~.se significantly the bulk of the.
chute.
Marine escape systems have also been proposed in which the
connection between the evacuation point and the inflatable
liferafts is via a tube containing a helical slide~passage.
See, for example, WO-A-84/D2658, WO-A-94/01324 and US-A-
3994366. A person entering the passage at the escape point
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travels iri a helical path along the passage and.emerges at an
exit at the lower end of the tube.
A tube requires less stabilization than a chute against
lateral movement in heavy weather. However, the tube has the
problem of accommodating swell which, as mentioned above, may
alter the freeboard of a vessel by six or more metres.
It has previously been proposed to accommodate this by making
the tube of flexible material with a maximum length sufficient
to accommodate the swell. The tube hangs from the evacuation
point on the structure and has excess length heaped on a
platform to which people are evacuated when the swell is less
than the maximum. As the space in between the platform and
the ecu.ation point varies, more or less of the tube is
either extended from or piled into the heap on the platform.
This.is disclosed in WO-A-94/01324.
It is a problem with such an arrangement_that no single exit
can be provided. In order to overcome this problem, such
tubes have previously been provided with a plurality of exits
spaced along their length; with evacuated persons emerging
from the exit closest to the platform at the time they reach
the platform. This is not, however, satisfactory because a
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person may exit too soon or the position of the platform may
change to make a selected exit suddenly inappropriate. .
According to the invention, there is provided a marine escape
- system comprising a passage for persons and having an entrance
at one end and an exit at an end opposite said one end, at
least one support for the passage being provided between the
entrance and the exit, the support being suspended by at least
one first elongate elastic member, at least one second
elongate elastic member extending from the support towards the
exit, the at least one second elongate elastic member having
a greater elasticity than the at least one first elongate
elastic member, so that a portion of the passage between the
exit and the support is extensible and contractible before the
- extension and contraction of a portion of the passage between
the entrance the support, the passage being extensible and
contractible to accommodate changes in the spacing between the
entrance and the exit.
-- By varying the length of the tube between the entrance and the ,
exit, a swell can be accommodated while maintaining a single
exit.
..
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According to a seconc! aspect of t:he inv.~ention, there is
provided an escape ch~.Ite comprising a plurality of slide
paths arranged successively along the escape chute, each
slide path including a converging pocket leading to an
aperture and a funnel outlet leading from said aperture to
provide a path for the passage of a p<-rson throu~~h the
escape chute.
The following is a more detailed description of some
embodiments of the invention, by way of example, reference
being made to the accompanying drawings in which:-
Figure 1 is a side elevation of a ship showing schematically
a marine escape system including two escape chutes leading
from an emergency exit to liferafts deployed on the sna,
Figure 2 is a side elevation of a part of one of the escape
chutes,
Figure 3 is a perspective view of part of the escape chute of
Figure 2,
Figure 4 is a cross-section through the escape chute of
Figures 2 and 3,
Figure 5 is an elevatian of one side of a right hand side cell
of an alternative fornl of escape chute,
Figure 6 is a front elevation of the right hand. cell shown in
Figure 5,
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Figure 7 is an elevation of the other side of the right hand
cell of Figures 5 and 6,
Figure 8 is a rear elevation of the right hand cell of Figures
to 7,
5 Figure 9 is a schematic view of an outer wall of the right
hand cell of Figures 5 to 8,
Figure 30 is a schematic view of the slide path assembly of
the right hand cell of Figures 5 to 9,
Figure 11 is a partial section of the right hand cell of
Figures 5 to 10 showing the slide path and the outer wall in
an extended disposition,
Figure 12 is a similar view to Figure 11 showing the outer
wall in a collapsed disposition,
Figure 13 is a similar view to Figure 12 but showing the whole
_ of a right hand cell with the outer wall in a collapsed
disposition,
Figure 14 is an elevation of one side of a left hand cell of
the alternative form of chute,
Figure 15 is a front elevation of the left hand cell,
- Figure 16 is an elevation ofthe other side of the left hand
cell,
Figure 17 is a rear elevation of the left hand cell of Figures
14 to 16,
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Figure 18 is a similar view to Figure 14 but showing the outer
wall of the left hand cell of Figures 14 to I7 in a collapsed
disposition,
Figure 19 is an elevation of one side of a bottom cell of the
S alternative escape chute,
Figure 20 is a front elevation of the bottom cell of Figure
19,
Figure 21 is an elevation of the other side of the bottom cell
of Figures 19 and 20,
Figure 22 is a rear elevation of the bottom cell of Figures 19
t o 21, and
Figure 23 is a similar view to Figure 19 but showing the outer
wall of the bottom cell of Figures 19 to 22 in a collapsed
disposition.
Referring first to Figure 1, the marine escape system
comprises two emergency exits 10 each leading to a respective
escape chute indicated generally at 11. Each escape chute
terminates at a respective liferaft 12 with two further
liferafts 12 also being provided. It will be appreciated that
the marine escape system is normally held a.n a container at
the side of the ship and deployed in an emergency, in a manner
to be described below.
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Referring now to Figures 2, 3 and 4, each escape chute 11
comprises a closed tube 13 of foldable material (such as a ,
fabric) formed into a helix_ The tube 13 may be provided with
stiffening bands 14 at spaced intervals along its length in
-. order to hold the tube 13 open.
The tube 13 is supported by a plurality of hoops 15 spaced
apart along the length of the tube 13. As seen in Figure 2,
there are eleven hoops 15, but there may be more or less hoops
as required. Each hoop 15 is made from a rigid alloy or a
carbon fibre material. A typical hoop diameter might be 2.3
metres.
As best seen in Figures 3 and 4, each hoop is provided with
six fixing points 16 equiangularly spaced around the exterior
of the hoop 15. The purpose of these will be described below.
As will be seen in Figures 2, 3 and 4, each hoop 15 is
positioned at a point along the length of the tube 13 where
the axis 17 of the tube is at a maximum spacing from the axis -
18 of the hoop. The tube 13 is held in this position by five
flexible but inelastic elongate members 19 and seven flexible
and elastically elongatable members 20. The inelastic members
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19 may be cords while the flexible members 20 are preferably
formed from a resilient elastomeric material.
The inelastic members 19 extend between equiangularly spaced
paints 21 on the portion of the periphery of the tube 13 lying
between two parallel planes, one extending through the tube
axis 17 and the other extending-through the hoop axis 18 and
both being normal to a hoop radius extending between the hoop
axis 18 and the tube axis 17. This is the portion of the tube
13 that faces the hoop axis 18_ In this way, the inelastic
members 20 fix the maximum spacing between the tube axis 17
and tube axis 18 so preventing the tube 13 moving any closer
to the hoop 15.
The elastic members 20 are also connected between the tube 13
and the hoop 15. Two of the elastic members 20 extend from
diametrically opposite points 22 on the periphery of the tube
13 and lying in a plane including the tube axis I7 and normal
to a radius extending from the hoop axis through the tube
axis. The remaining elastic members 20 are equiangularly
spaced around the periphery of the tube 13 between these two
points 22.
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The elastic members 20 thus allow the tube 13 to move so that
the spacing between the axis of the tube 17 and the axis of
the hoop 18 decreases. The elastic members 20 are permanently
in tension and so they provide a force tending to restore the
5 tube 13 to the position shown in Figure 3. This may be a
position a.n which the helical tube 13 has a helix angle of
30°.
The hoops 15 themselves are also interconnected by flexible
10 members of two kinds; inelastic flexible members 23 and
elastic flexible members 24.
The inelastic flexible members 23 extend from a support 25 at
the top of the escape chute 11 and the sixth hoop 15, as seen
in Figure 2. There are six members 23 equiangularly spaced
around these hoops 15 and connected at each hoop 15 to an
associated one of the fixing points 16. Thus, the inelastic
flexible members 23 fix the maximum spacing between the first
and sixth hoops 15.
-
The sixth hoop 15 is connected to an associated lif eraft 12 by
the elastic flexible members 24. There are three different
types of elastic flexible member 24, the types having
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different elasticities. The first elastic members 24a are the
least elastic and~they extend between the sixth hoop 15 and
the eighth hoop 15. There are six members 24a and they are
attached to the fixing points 16 on the sixth, seventh and
eighth hoops 15.
The second elastic flexible members 24b are more elastic than
the first elastic flexible members 24a. There are six of
these members 24b and they extend between the eighth hoop 15
and the tenth hoop 15 and are connected to the fixing points
16 on these hoops.
The third elastic flexible members are connected between the
tenth hoop 15 and the associated liferaft 12_ They are more
elastic than the second elastic flexible members 24b. There
are six of these members 24c and they are connected to the
f fixing points 16 on the tenth and eleventh hoops 15 and to
fixing points (not shown) on the liferaft 12.
A typical first elastic flexible member 24a might have a
diameter of 19mm and extend in excess of 4000mm under a load
of about 7.5N. Each second elastic flexible member 24b might
typically have a diameter of 16mm and extend in excess of
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12
4000mm under a load of about 5.5N. Each third elastic
flexible members 24c might have a diameter of 12.5mm and ~
extend in excess of 4000mm under a load of 3.5N.
The outside of this structure may be covered by a fabric tube
(not shown) of generally the same diameter as the hoops 15.
Each exit 10 is connected to the support 25 at the upper end
of the escape chute 11. This provides an exit from the ship
and leads to the entrance to the escape chute 11 at the upper
end of the escape chute 11.
The liferafts 12 are formed by inflatable tubes 26 and are
provided with a fabric cover 27. The liferafts are generally
rectangular in plan view and, as shown in Figure 1, are held
together in a rectangular array. Each escape chute 11
provides at its lower end an exit within an associated one of
the liferafts 12.
In use, the liferafts L2 are deflated and are held with the
escape chutes 11 in a container mounted at the exits 10 on the
ship. It will be appreciated that the escape chutes 11
require very little space because the hoops 15 will collapse
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to lie on top of one another and the fabric of the tube 13 can
readily be collapsed. The members 23,24 will also collapse
into a comparatively small space.
In an emergency, the liferafts 12 and the escape chutes I1 are
ejected from the container and the exits 10 opened. As they
deploy, the liferafts 12 are inflated from a source of gas
under pressure (not shown) in conventional fashion. The
liferafts 12 are provided with water pockets (not shown)
which, as the liferafts 12 hit the sea, fill with water. The
weight of the liferafts 12 and the length of the inelastic
members 23 and the elastic members 24 are chosen so that, in
a calm sea and with the ship normally loaded, the inelastic
members 23 are fully extended and the elastic members 24 are
under tension. As indicated above, typical elastic members 24
may provide between them an extension in excess of 12000mm.
In this case, the arrangement may be such that in calm sea the
flexible members 24 are extended by 6000mm.
' 20 The extension of the members 24 increases the spacing between
the sixth hoop 15 and the associated liferaft 12. This
causes the tube 13 to have an increased helix angle, as seen
in Figure 2. This in turn causes straightening of the tube
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and thus extension of the flexible elastic members 24
connecting the tube 13 to the hoops 15 with the tube 13 moving
towards the axis 18 of the hoops 15.
When deployed in this way, persons can enter the entrance at
one end of the tube 13, slide through the tube in a helical
path and emerge within the liferaft. They are, therefore,
never exposed to the outside elements in the whole of their
travel between the ship and a liferaft 12.
Sea swell will cause the liferafts 12 to move up and down
relative to the exits 11 so increasing and decreasing the
freeboard of the ship. This is accommodated by extension and
retraction of the elastic members 24 and by extension and
- retraction of the tube 13_ The third elastic members 24c will
extend first follo~aec3. by the second elastic members 24b and
followed by the first elastic members 24a. The weight at the
end of the tube 13, provided by the liferafts 32, is
sufficient to cause this extension without the liferafts 12
lifting out of the sea. The position of the axis I7 of the
tube 13 will also change, with such changes being accommodated
by the flexible members 20. As this occurs, the helix angle
of the tube 13 will vary.
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It will be appreciated that there are a number of variations
that can be made to the marine escape system described above
with reference to-the drawings.
5 There need not be two escape chutes 11; there could be one or
three or more. The or each escape chute 11 need not terminate
within a laferaft 12; it could terminate at a floating
platform to which liferafts are attached.
10 In an alternative arrangement, the tube 13 may split at a
point along its length into two parallel tubes so that persons
evacuating the ship can pass successively down one and then
the other of the tubes.
15 The connections between the hoops need not be formed by
flexible members 24; they could be formed by any suitable
extendible member such as a spring.
Although the arrangement described above is elastically
extendible and retractable only from the sixth hoop 15 to the
liferaft 12; it could be elastically flexible all the way
along its length or between the laferafts and hoops other than
the sixth hoop 15.
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It will also be appreciated that the weight of the liferafts
12 at the end of the escape chutes 11 tend to keep the chutes
in a vertical disposition. This minimizes the requirement for
any stabilization of the position of the escape chutes 11
S relative to the ship.
The escape path for evacuees need not be a helical tube; it
could be an open-topped helical chute or a tube containing a
succession of alternately oppositely facing panels spaced
along the length of the tube, each panel being angled relative
to the length of the tube. A person entering the tube slides
down one panel and then turns to slide down an oppositely
facing panel and so on until the end of the tube is reached.
In this case, the panels may be of flexible material to
accommodate extension and retraction of the tube.
Referring next to Figures 5 to 22, there will now be described
an alternative form of the escape chute shown in Figure 1.
In this embodiment, the escape chute is formed from three
different kinds of cell. A left hand cell 30 shown in Figures
5 to 13, a right hand cell 31 shown in Figures 1.4 to 18 and a
bottom cell 32 shown in Figures 19 to 23. The right hand and
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left hand cells 30, 31 are joined end to end alternately to
form the chute, in a mannerto be described in more detail
below, and the bottom cell 32 is attached at the end, again in
a manner to be described in more detail below.
Referring-first to-Figures 5 to 13, the left hand cell 30 is
formed from a cell wall 33, best seen in Figure 9, and a slide
path 34, best seen in Figure 10. The cell wall 33 is, as seen
in Figure 9, generally cylindrical and formed of a high
strength waterproof fabric. As best seen in Figures 5 to 8,
the cell wall 33 has an upper edge 35 provided with a
circumferentially spaced series of loops 36. The cell wall 33
also has a lower edge 37 with similar spaced loops 38. A
series of tubular pockets 39 extend around the cell wall 33
L5 intermediate the upper edge 35 and the lower edge 37 to form
an interrupted annular passage around the cell wall.
The function of the loops 36, 38 and the pockets 39 will be
described below.
The cell wall 33 contains a slide path 34, best seen in Figure
10. The slide path 34 is also formed from strong waterproof
fabric.
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The slide path 34 comprises a back panel 40 which is generally
elongate with a rounded upper end edge 41 and a convexly
curved side edge 42. The edge of the side of the back panel
40 opposite the side edge 42 is straight and the lower edge 44
= of the back panel 40 opposite the upper end edge 41 is also
straight. A diverter panel has an edge connected to the
straight edge 43 of the back panel 40 and lies in a plane that
subtends an obtuse angle to the plane of the back panel 40.
An outer skirt panel 46 curves between a lower portion of the
outer edge 47 of the diverter panel 45 and a Lower portion of
the side edge 42 of the back panel. The back panel 40, the
diverter panel 45 and the outer skirt 46 thus between them
fornl a converging enclosed pathway or pocket. This terminates
in an aperture 48.
The slide path 34 is connected inside the cell wall 33 in tree
following way_
The upper end edge 41 of the slide path 34 is connected to the
interior surface of the cell with the apex of this edge 41
being adjacent the upper edge 35 of the cell wall 33. This
connection continues around the upper end edge 41, the side
edge and the outer edge 47 of the diverter panel 45, until
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approximately the level of the pockets 35. In addition, the
_ outer skirt 46 has an upper edge 50 that is also connected to
the interior of the outer of the cell wall 33 also roughly at
the level of the pockets 35.
Thus , as seen in Figures 5 to 8 , the back panel 40 extends
diagonally across the cell wall 33 between the upper edge 35
and the lower edge 37. As seen in Figure 7, the diverter
panel 45 is at an obtuse angle relative to the back panel 40.
The funnel outlet 49 extends downwardly beyond the lower edge
37 of the cell wall 33. In this way, as seen in Figure 13,
the lower part of the cell wall 33 can be collapsed upwardly
without affecting the disposition of the slide path 34. The
purpose of this will be described below.
The right hand cell 31 will now be described with reference to
Figures 14 to 18. As seen in these Figures, the cell is
largely identical to the left hand cell 30 and the common
parts will not be described in detail and will be given the
same reference numerals. The difference between the right
hand cell 31 and the left hand cell 30 is that, in the right
hand cell 31, the slide path 34 is rotated by 90° relative to
the loops 36,38 as compared to the slide path 34 of the left
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hand cell 30. This allows the loops 35,38 to form a passage
in a manner to be described below. ,
The bottom cell 32 is formed by an annular cell wall 55 having
5 an upper edge 56 provided with loops 57 which are the same as
the loops 36 on the upper edge 35 of the cell wall 33 of the
left hand cell 30. The cell wall 55 has, however, no pockets
35 and no loops on its lower edge 58. The length of the cell
wall 55 between the upper edge 56 and the lower edge 58 is
10 longer than the length of the cell wall 33 of the left hand
cell 30 between its upper edge 35 and lower edge 37_ The cell
wall 55 contains a slide path 59 which is identical to the
slide path 34 in the left hand cell 30 and is connected to the
cell wall 55 in the same way as the slide path 34 is connected
15 to the left hand cell 30. Thus, as seen in Figures 18 to 22,
the funnel outlet 49 projects only a short distance below the
lower edge 58 of the cell wall 55. However, the back panel 40
may be perforate to allow water to drain through the panel 40.
20 The chute is formed by connecting together left and right hand ,
cells 30,31 alternately until a chute of the required length
has been formed. The cells are so arranged that the back
panel 40 of each slide path 34 is skewed by 90° relative to
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the preceding and succeeding back panels 40. The skewing is
successively in the same sense (either clockwise or
anticlockwise).
The cells 30,31 are interconnected by hoops (not shown). The
loops 38 at the lower edge 37 of one slide path 34 (of a left
or right hand cell 30,31) fit between the spaces of the loops
36 of the upper edge of the next slide path 34 (of a right or
left hand cell 31,30). There is thus formed a continuous
tubular passage through which a hoop extends to forth the
connection. The hoops may, for example, be made of metal.
The bottom cell 32 is connected to the lowermost left hand or
right hand cell 30,31 in the same way; by a hoop passing
through the passage formed by the loops 36,38.
A hoop 53 is also passed through the tubular pockets 39
between the upper and lower edges 35,37 of each cell wall 33_
The effect of these hoops 52,53 is to hold the cell walls 33,
55 open while permitting them to be collapsed.
The hoops 52 at the upper and lower edges 35,37 of the cell
walls (but not the intermediate hoops 53) are connected
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together by elastic members which are arranged in the same way
as the elastic members 19 connecting the hoops 15 in the
embodiment described above with reference to Figures 2 to 4_
The escape chute so formed is connected between a ship and a
life raft 12 in a manner of the escape chute described above
with reference to Figures 2 to 4.
This embodiment of the escape chute forms, in essence, a
spiral path between the uppermost cell 30,31 and the bottom
cell 32. A person entering the uppermost cell 30,31 initially
sits on the back panel 40 of the first slide path 34. As the
person travels down the back panel 40, they engage the
diverter panel 40 and this twists them in anticlockwise
direction. They then pass through the funnel outlet 49 to
- engage the backpanel 40 of the next succeeding cell 30, 31
which is skewed by 90° to the back panel 40 the person has
just left. The effect of the funnel outlet and the skewed
arrangement of the back panels 40 is to cause the person to
slow down by friction engagement with the material of the
slide path and by the constriction provided by the funnel
outlet. A person travelling through the escape chute thus
reaches a safe speed at which the person passes in a spiral
path through succeeding slide paths 34 until the bottom cell
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32 is reached. As the person leaves the bottom cell 32
through the funnel outlet 49, they enter the life raft 12 as
described above with reference to Figures 1 to 4.
As the spacing between the life raft 12 and the ship varies,
such variation is accommodated by the collapse and extension
of the chute under the control of the flexible members 20
which progressively collapses the chute from the bottom cell
32 upwards, as described above with reference to Figures 1 to
4.
As a result of the way in which the slide paths 34 are
connected to the cell walls 33,55, such collapsing of the
walls 33,55 does not collapse the slide paths 34. As the
escape chute length gets shorter, they merely concertina into
one another so that, as a person leaves a funnel outlet 49 of
one cell 30,31 they engage the back panel 40 of the next
succeeding cell 30,31 at a position lower down the back panel
40 than the person would if the cells 30,31 were fully
extended.
It will be appreciated that there are a number of variations
that can be made to this second form of escape chute. The
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slide path 34 need not be formed as described. It could have
any shape which guides and controls the path of a person
through the chute. The cells 30,3I,32 need not be connected
by loops 36,38 as described above, they could be connected in
- any suitable way. The cell walls 33,55 need not be
continuous; they may include cut-outs.
