GB2252283A - Escape chute - Google Patents

Abstract

An escape chute assembly, intended for use as a mass evacuation unit through which a succession of persons can escape in an emergency from a multiple-occupancy location (for example an off-shore oil drilling rig) or a high-rise tower-block and comprising a generally helical pipe 14 large enough internally for a person to slide through; wherein the pitch of the generally helical pipe may be selectively altered between an operative and an inoperative position. <IMAGE>

Description

ESCAPE CHUTE Field ot the Invention The present invention relates to escape chutes; and especially to escape chute assemblies intended for use as mass evacuation units through which a succession of persons can escape from a multiple-occupancy location (for example an off-shore oil-drilling rig or a high-rise tower-block.).

Background to the Invention The need for safe, efficient, convenient and secure escape from multiple occupancy locations is well known. Given that lifts cannot be used during fire-emergencies in high-rise tower-bloci;s, thee is an immediate concern about escape facilities.

Off-shore oil-drilling rigs, or other work stations, have similar difficulties.

The need for some form of escape to be provided from multipleoccupancy work stations, such as oil-drilling rigs, has been graphically illustrated by recent events. For instance, in the socalled "Piper Alpha' tragedy many lives may have been saved, and serious injuries prevented, if a rapid deployment escape apparatus had been installed to allow those on the station to quickly and safely leave the immediate environment of the conflagration and descend, in a controlled manner, to flotation devices at sea-level.

Summarv of the Invention According to the present invention, there is provided an escape chute assembly, intended for use as a mass evacuation unit through which a succession of persons can escape in an emergency from a multiple-occupancy location (for example an offshore oil drilling rig) or a high-rise tower-block and comprising a generally helical pipe large enough internally for a person to slide through; wherein the pitch of the generally helical pipe may be selectively altered between an operative and an inoperative position.

The generally helical pipe may be located around a central supporting pillar. Alternatively, the helical pipe may be supported by a cable supported by the structure of the location. Often there will be a plurality of cables supporting the generally helical pipe.

The invention will now be described, by way of example only, with reference to the drawings that follow; in which: Brief Description of the Drawings Figure 1 is a schematic representation of an escape chute in accordance with the present invention showing part of the escape chute in its operative (deployed) position.

Figure 2 is a schematic representation of the escape chute shown in Figure 1 in an inoperative (stored) position.

Figure 3 is a schematic representation of an escape chute in accordance with the present invention in its inoperative (stored) position, illustrating an alternative winch and support system for the present invention.

Figures 4 to 10 are schematic representations of further escape chute assemblies in accordance with the present invention.

Figure 11 shows schematic representations of possible pipe section structures.

Descrintion of the Preferred Embodiments It is to be noted that, whilst the following description relates to the use of the present invention on Off-shore oil-drilling wori stations, it may also be used for other locations such as blocks of high-rise flats so long as some form of support structure is provided.

Referring now to Figures 1 and 2 of the drawings that follow, there is shown an escape chute assembly 2 mounted on a multiple occupancy work station, in this case an off-shore oil-drilling rig 4, a lower platform 6 of which can be seen in Figure 2.

Mounted above the platform 6 there is an entrance 8 to the escape chute 2 located to be suitable for convenient and rapid human entry. Signs (not shown) on the rig 4 will clearly indicate the route to the escape chute 2 which will normally be located within a control cabin (not shown) having an emergency-door type entrance.

The entrance 8 comprises an approximately 90 centimetre diameter circular first pipe section 10 that is linked (in a manner more fully described below) sequentially to a plurality of further pipe sections 12, the pipe sections 10, 12 being so linked as to form a generally helical pipe 14. It is to be noted that the term 'helical' is not restricted to strictly mathematically defined helices, and includes generally helical shapes such as helices of varying diameter and pitch along their length.

The helical pipe 14 is mounted around a central pillar 16 that provides support for the chute 2.

Referring now to Figure 1 of the drawings that follow in which the chute 2 is shown in an operative (deployed) position. The pipe 14 is deployed in the general shape of a helix having a substantially constant pitch of approximately 6 metres and a substantially constant diameter of approximately 4 metres. The further pipe sections 12 are attached by brackets 18 and a track roller running gear 20 (both known), to longitudinal tracks 22 fixed to the outer periphery of, and running vertically along, the pillar 16. The first pipe section 10 is also attached to a running track 22 by a fixed bracket 24. The brackets 18 are of the socalled saddle-type with swivel joints attaching them to the running gear 20 and to swivel-type moulded connection joints 26.

The fixed bracket 24 is not swivel jointed and is connected to a non-swivel jointed moulded connection joint 28. The moulded connection joints 26 provide additional rigidity for the pipes 10, 12.

The running gear 20 engages the tracks 22 and is generally freerunning therein. At stop points positioned in each track 22 there are fixed stop-blocks 30 that limit the extent of travel of the running gear 20.

In Figure 2 the escape chute 2 is shown in its inoperative (stored) configuration in which the helical pipe 14 is compressed into a tight coil. The Figure also shows, at the exit point 32 of the helical pipe 14 a final escape assembly 34 which serves to provide variable height egress for varying sea conditions. In this embodiment the final escape assembly 34 is a telescopic escape assembly substantially as described in United Kingdom patent application No GB 2 232 138, the disclosure of which is included herein by reference, although in this case it acts as a final escape assembly rather than as the entire system. As an alternative the final escape assembly 34 could comprise an inflatable chute, for instance similar to that described in United Kingdom patent specification No GB 1 419 518.

On one of the helical pipe sections 12 there can be seen winch cable fixings 36 to which are attached cables 38 extending from a motorised winch 40. The cables 38 pass between the inside of the pipe 14 and the outside of the pillar 16.

All of the pipe sections 10, 12 are formed from a rigid fibre glass moulding comprising alternating layers of fibre glass and a suitable fire resistant laminating resin, for example a resin conforming to BS 476 Part 7 1971. Such resin is currently sold in the UK under the trading style NORPOL 84-73 by Jotun Polymer.

The interiors of the pipes 10, 12 are large enough internally for a person to slide there through. The pipes 10, 12 provide an enclosed tubular passageway from the entrance 8 to the exit point 32. To assist in the passage of the evacuees the interior surfaces of the pipe sections 10, 12 will generally be sufficiently smooth to allow a person to slide continuously through the series of linked pipes 10, 12. Water may be used as a lubricant along the length of the pipe 14. To avoid the danger of excess speed hand holds, ribs, rubber strips or other breaking means may be provided to allow evacuees to slow their descents. The final escape assembly 34 may include a breaking region to assist in decelerating any evacuees before they leave the chute 2; this is especially useful for unconscious or injured evacuees.

Both the exterior and the interior of the pipe 14 may be illuminated by lights powered preferably from an emergency electrical source. The exterior is illuminated to indicate the presence of the assembly 2, the interior is illuminated to assist the evacuees. Alternatively, luminous strips or patches may be used on the exterior of the pipe 14.

The further pipe sections 12 are approximately 4 metres long from entrance to exit; they are joined together by forming compression fits against one another. Each section 12 has a tapered end 42 that is located within the wider (non tapering) entrance of the next pipe section 12 (proceeding in a downwards direction through the pipe sections). Thus, as evacuees pass from the first pipe section 10 to the first further pipe section 12, or between successive further pipe sections 12, they experience a slight drop - instead of running up against a raised lip if the sections 10, 12 were engaged in the opposite orientation. The tapering end 42 extends approximately one-third of the length of the next pipe section 12 thus allowing for a variety of diameters to be provided for within this single construction.

Variations in the number of further pipe sections 12 allow different heights to be accommodated. Any suitable number of coils may be employed in the helix. The tapering end 42 also allows a certain amount of relative movement between the pipe sections 12 as they are deployed or stored. Further relative movement is provided for by the inherent flexibility of the pipe sections 10, 12. Any form of limiting means, such as a ratchet, a flange running in an enclosed channel or a secured cable, may be used to prevent the successive pipe sections 10,12 coming loose from their adjacent sections.

The transfer of the escape chute 2 from its inoperative (stored) position to its operative (deployed) position will now be described in more detail.

The helical pipe 14 can be lowered into its operative (deployed) position, shown in Figure 1, by paying out the cable 38 from the winch 40 - the winch 40 is run from an independent power source (not shown) that is well protected should an accident occur. The winch may be powered electrically, pneumatically, hydraulically or even manually if necessary.

Provision may also be made for the emergency deployment of the chute 2 by simply allowing the helix to form under gravity, the cable 38 being dragged from the winch 40. In this case the assembly 2 is preferably critically damped (by a friction brake applied to the winch 40) to avoid unwanted oscillations and damage to the chute.

The pitch of the helical pipe 14 may therefore be selectively altered between an operative (Figure 1) and inoperative (Figure 2) position. In this embodiment the chute is deployed at approximately 450 to the horizontal.

The deployment of the chute 2 may automatically trigger such devices as emergency beacons, klaxons, flares, search lights, buoyancy aid launches, etc. Any lighting systems within, or on, the chute 2 will also be activated automatically upon deployment.

In some emergency conditions evacuees may enter the chute whilst it is being deployed - although this is generally inadvisable.

In whatever way the chute 2 is deployed each set of running gear 20 travels down the fixed tracks 22 until they reach and abut against, the stop-blocks 30. The final escape assembly 34 may then be deployed and the chute 2 is ready for use. In order to provide extra safety a floatation platform may be used at final exit 44 of the final chute assembly 34 onto which evacuees will be deposited from the chute 2. Once the chute 2 is fully deployed and operative a signal will indicate this fact to the waiting evacuees.

In normal circumstances the evacuation will then proceed. Various life rafts, or other buoyancy aids, may be located nearby and attached to the final exit 44 or a floatation platform (if present) in order to ensure an orderly departure from the final exit region.

The floatation platform and buoyancy aids may be deployed using any conventional method - or may be attached to the final exit 44 of the chute 2 and deployed accordingly, for instance so that they are inflated on contact with the water.

The chute 2 may be returned to its stored (inoperative) position.

The winch 40 lifts the assembly which is locked in place once it reaches its stored position.

Referring now to Figure 3 of the drawings that follow, there is shown an alternative construction of an escape chute in accordance with the present invention.

The basic principle of the helical escape chute is unchanged.

However, differences arise in the entrance structure, the support of the chute and its deployment. These differences will now be described in more detail using like reference numerals for like parts.

The entrance 8 is a swing-type entrance providing a seating platform 46 onto which an evacuee lowers himself, in this position the evacuee's feet extend into the first pipe section 10. The entrance 8 also comprises a ribbed bar 48 which may be conveniently grasped by hand. Any evacuee sitting on the platform 46 slides downwards into the first pipe section 10 swinging himself about the ribbed bar 48.

In this embodiment the helical pipe 14 is supported solely by winch cables 50. Each full coil of the helix has at least one winch cable 50 attached thereto at an attachment point 52, although a single cable may suffice. Each winch cable is attached, at its opposite end, to its own winch 54 that is - separately powered and geared. Between the attachment point 52 and the winch 54 the cable 50 runs over a pulley 56. The winches 54 are located within a winch box 58 suspended beneath the lower platform 6; the pulleys 56 ensure that the pulleys encounter a suitable force component from their winch cables 50.

The vertical deployment of the chute 2 from its inoperative (stored) position to its operative (deployed) position is governed solely'-. by the winches 54 in this embodiment. The winches 54 are used to lower the pipe 14 in a controlled fashion, or in an emergency power failure are able to freely release the pipe 14, in a similar manner as described above for the first embodiment, until they reach their operative positions in which they are locked as a fail-safe.

This embodiment is more readily portable than the embodiment described above and is generally suitable for less hazardous conditions.

In some circumstances it may be advantageous to use a helical pipe that is substantially elliptical when viewed along the longitudinal axis of the helix. The tighter corners assist in breaking the descent of evacuees.

Another possible option is to mount the assembly 2 on a rotatable (about the helix's longitudinal axis) support structure so that, where required, the assembly may be turned to ensure that the evacuees emerge facing away from the wind.

In figures 4 to 10 further embodiments are illustrated with LIKE numerals referencing like parts. The embodiments are similar in principle to those described above. In these embodiments the generally helical pipe is supported by a single central longitudinal cable 100 to which the pipe sections 102 are attached by cable guides 104 that slide along the cable 100. A cable stop 106 is provided at the bottom of the cable 100 to prevent the cable guides 104 coming off the end of the cable 100.

Figure 11 shows details of a possible pipe section structures.

It will be appreciated by those skilled in the art that various features of the embodiments described above may be combined within the scope of the present invention.

It is to be noted that the sizes and relative dimensions referred to in this specific embodiment are not intended to limit the scope of the present invention but are merely intended to serve as illustrative examples.

One particular advantage of the present invention is that it makes the evacuation of injured and/or unconscious persons easier and safer.

Claims (4)

CLAIMS:

1. An escape chute assembly, intended for use as a mass evacuation unit through which a succession of persons can escape in an emergency from a multiple-occupancy location (for example an off- shore oil drilling rigJ or a high-rise tower-block and comprising a generally helical pipe large enough internally for a person to slide through: wherein the pitch of the generally helical pipe may be selectively altered between an operative and an inoperative position.

2. An escape chute assembly according to Claim 1 in which the generally helical pipe is located around a central supporting Nllar.

3. An escape chute assembly according to Claim 1 in which the helical pipe is supported by a cable supported by the structure of the location.

4. An escape chute assembly, as described herein, with reference to and as illustrated in Figures 1-2, 3 and 4-10.