GB2393652A

GB2393652A - Escape apparatus for tall buildings

Info

Publication number: GB2393652A
Application number: GB0223114A
Authority: GB
Inventors: Michael Godwin
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-10-04
Filing date: 2002-10-04
Publication date: 2004-04-07
Also published as: GB0223114D0

Abstract

A building escape system includes a chair located on track rails running down the outer facade of a building. Both chair and track contain components of a linear electromagnetic generator so that the chairs gravitational descent will produce electrical current sufficient to reduce velocity to a safe level.

Description

( 2393652

Rapid Escape Apparatus for Buildings or Structures above 30m in height Existing escape systems other than stairs rely upon friction braking to limit each persons descent velocity in an escape tube, however with building heights now reaching 300 meters simple friction braking using escape tubes are no longer a feasible proposition.

This invention relates to any self-powered gravity operated escape apparatus and specifically includes a compact chair unit(s) fitted with a harness available to all occupants of high-rise buildings or structures for the purpose of escape in an emergency.

Attached to the chair unit is one active half of an open frame AC (altemating current) permanent magnet linear electro-magnetic generator (a half of an open frame AC permanent magnet linear electro-magnetic generator being defined as either the permanent magnet(s) or the copper wire wound iron stator(s)) the other active half being fixed top to bottom as a track on any tall edifice e.g. tall building/structure.

The object of this invention is to provide the means of rapid escape from any tall building permitting a stream of persons of varying weights to be dispatched downwards with minimum time delay whilst avoiding contact with each other throughout a descent of up to three hundred meters.

Each dispatcher situated at various levels throughout the building is able to deal with persons escaping at the approximate rate of two hundred and fifty in a twelve and a half minute period. The continuous power generated by any descending person is fully absorbed and dissipated electrically in the series circuit of the AC permanent magnet linear electro-magnetic generator.

Consequently chair units with persons can descend serially at substantially constant velocity to disperse at the ground level.

Accordingly this invention is designed to satisfy the essential criteria that the AC permanent magnet linear electro-magnetic generator must generate enough retarding force in the air gap to equal the weight of each chair unit and passenger descending. In one active half of the generator therefore sufficient iron and copper is incorporated to ensure that magnetic saturation does not occur under the maximum power condition, it's construction being substantially the same as any traditional standard AC linear motor design the other active half of which uses high flux density permanent magnets.

Descent velocity is substantially constant and controlled to accommodate some variation in chair load by tuning the series circuit of the AC permanent magnet linear electro-magnetic generator such that as the descent velocity and hence the AC frequency starts to become in tune with the series circuit the generated current rises rapidly, so increasing the retarding force in the air

( gap and preventing any further acceleration of descending loaded chair descending. A specific embodiment of the invention will now be described by example and with reference to the accompanying drawings in which: FIGURE 1 shows side view of chair unit with collapsible seat and integral guide wheels and one active half of the AC permanent magnet linear electro-

magnetic generator.

FIGURE 2 shows the rear view of a chair unit with its integral guide wheels, hanger rollers and one active half of the AC permanent magnet linear electro-

magnetic generator.

FIGURE 3 shows the front view of a chair unit located in the substantially vertical guide rail and magnetically coupled with person secured ready for dispatch. FIGURE 4 shows a section through chair unit and guide rail in position with both active halves of the AC permanent magnet linear electro-magnetic generator magnetically coupled across an air gap.

FIGURE 5 shows detail of the two active parts magnetically coupled together ready for descent and also the air gaps where the retarding forces are generated. FIGURE 6 shows a chair unit located in a track with a person descending in escape mode.

FIGURE 7 shows a typical deployment of a hanger track feeding chair units that are being occupied at a muster station ready for dispatch and an arrangement at exit level showing persons arriving at lowest level and dispersing and the recovery and storage of chair units.

FIGURE 8 shows a tall building during simultaneous evacuation of occupants from muster stations located throughout the building.

FIGURE 9 shows a modified universal resonance curve of the Force (Newton's) generated in the air gap against Velocity (m/s) and its equivalent frequency for a pole pitch of 16.66 mm.

FIGURE 10 shows a schematic of the AC permanent magnet linear electro-

magnetic generator series circuit comprising Inductance (L), Capacitance (C) and Resistance (R).

Referring to the drawing in FIGURE 1 depicting a chair unit with seat [11] arranged to be hinged [12] with securing straps [13] the whole unit being made lightweight using plastic and suspended from a hanger rail [14] to enable easy movement from storage to its dispatch position. As an integral part of the chair unit FIGURE 2 is one active half of an AC permanent magnet

( linear electro-magnetic generator [15] positioned such that in conjunction with guide rollers [16] the chair unit can be positioned to magnetically couple with the other half or halves of an AC permanent magnet linear electro-magnetic generator fixed from top to bosom of a tall building/structure.

A person sitting on the chair unit and secured is depicted in FIGURE 3 ready to be assisted by competent authorised persons into the dispatch area where guide rollers engage track [17] and by magnetically coupling both halves of the AC permanent magnet linear electro-magnetic generator prepare for imminent dispatch. FIGURE 4 FIGURE 5 shows in detail the two halves of the AC permanent magnet linear electro-magnetic generator [18] magnetically coupled across an air gap [19] in which the retarding force [see FIGURE 10] is generated once the chair is dispatched. The half of the open frame AC permanent magnet linear electro-

magnetic generator integral with the chair unit [20] contains the series tuned circuit [21] directly connected across the generator output consisting of its inductance (L) Henry's [22] its resistance (R) in Ohms including an external load resistance [23] and (C) in Farads its tuning capacitance [24] FIGURE 10.

Once a chair unit and secured person [25] has been located in the substantially vertical track ready for dispatch FIGURE 6, the chair unit is released and accelerates under gravity, this force being far in excess of any friction force that could restrain the chair units descent.

Movement of one half of the AC permanent magnet linear electro-magnetic generator relative to the other half generates an alternating electromotive force which will cause some current to flow in the AC permanent magnet linear electro-magnetic generator winding and hence producing some force opposing this movement. In less than one second of free fall the chair unit and person will have reached its maximum design descent velocity.

FIGURE 9 depicts the manner in which the retarding force builds up [26] within the first second of free fall where the alternating electro-motive force amplitude and its frequency rapidly rise, however the alternating current and hence the retarding force it produces stays more or less constant due to the reactive voltage drop across the generator inductance (L) [22] until the frequency of the AC permanent magnet linear electromagnetic generator output approaches the base of the resonance curve [27]. At this point the alternating electro-motive force voltage drop across the inductance (L)[22] becomes less due to the action of the capacitance (C) [24] so permitting the current to rise and proportionally increase the retarding force generated in the air gap [19]. Any further increase in descent velocity causes the retarding force to build up very quickly so preventing any further acceleration under gravity of the chair unit [20] and descent continues at a substantially constant velocity e.g. 5 m/s.

The choice of any particular descent velocity is substantially determined by the values of the passive components L [22] C [24] and R [23] and the limits imposed by magnetic saturation [28] of the iron in the AC permanent magnet

( linear electro-magnetic generator. To ensure that descent velocity NEVER reaches the peak of the resonance curve FIGURE 9, an appropriate choice of the passive components within the series circuit comprising of L, C and R FIGURE 10 must be made together with the appropriate sizing of the AC permanent magnet linear electro-magnetic generator such that an adequate retarding force will always be generated over the operating range [29] providing an inherent safety factor, that will accommodate the maximum variations in weights of loaded chair units.

This narrow operating range [29] is achieved by designing the Q factor of the resonant series circuit to be of a value that ensures the steepness [30] of the side of the modified universal resonance curve is great enough to result in a substantially constant descent velocity for varying weights of loaded chair units. FIGURE 7 depicts a possible means of deploying chair units [31] using a hanger track [14], which allows the chair units to be easily taken from a storage position [32] to the muster station for use by building occupants.

Moving the chair units manually into the dispatcher by trained/competent authorised personnel [33] would ensure a speedy dispatch for escaping occupants with an average interval of three seconds per person.

FIGURE 8 depicts chair units descending [34] with persons as they approach and continue to exit at the ground level. Descent velocity approaching ground level is slowed by the use of additional braking force provided by the permanent magnet(s) of one half of the AC permanent magnet linear electro-

magnetic generator engaging aluminium plates in close proximity to induce eddy currents of sufficient magnitude to reduce the final velocity to 0. 75 m/s approximately at which point the chair units engage a hanger rail as they change direction [35] from vertical to horizontal permitting occupants to have time to safely release themselves whilst trained/competent personnel will collapse the chair units and remove them to a storage area.

Claims

Claims

What I claim is: 1. A gravity operated escape apparatus not requiring any external power supplies, comprising compact chair type unit(s) provided for all occupants of any tall building/structure that have built into or attached to the chair unit(s) one active half of an open frame AC (alternating current) permanent magnet linear electro-magnetic generator (a half of an open frame AC permanent magnet linear electro-magnetic generator being defined as either the permanent magnet(s) or the copper wire wound iron stator(s)) capable when magnetically coupled to another active half of an AC permanent magnet linear electro-magnetic generator that is fixed from top to bottom of a tall building/structure of delivering sufficient power at some specified descent velocity to counter balance the power generated by a descending chair unit(s) loaded with passenger(s) thus preventing any further acceleration and stabilising the velocity of any descending occupied chair unit(s) using as the means to achieve a stabilised descent velocity a resonanVtuned series circuit with passive components connected to the output of the AC permanent magnet linear electro-magnetic generator so permitting the increase in current from the AC permanent magnet linear electro-

magnetic generator in order that the retarding force output generated across the air gap is sufficient to counterbalance the gross weight of any occupied chair unit's so substantially limiting its descent velocity.
2. A gravity operated escape apparatus as claimed in Claim 1 above where one active half of a single or plurality of AC permanent magnet linear electro-magnetic generator(s) is magnetically proportioned such that when magnetically coupled together the power generated by each descending chair and passenger (occupied chair) is fully absorbed and dissipated by the passive electrical resistance(R) without the iron in the magnetic circuit of the generator becoming saturated.
3. A gravity operated escape apparatus as claimed in Claim 1 above where the Q factor of the resonanVtuned series circuit of the AC permanent magnet linear electro-magnetic generator is high enough to regulate the descent velocity such that varying weights of descending chair and passenger units do not cause significant variation in descent velocity.
4. A gravity operated escape apparatus as claimed in Claim 1 above where the chair units are suspended from a guide rail ready to be easily deployed and can be folded or otherwise compacted for the purpose of minimising storage space.
5. A gravity operated escape apparatus as claimed in Claim 1 above where the permanent magnet half of the AC permanent magnet linear

/ electro-magnetic generator is brought into close proximity of a conducting element to induce eddy currents to provide a braking force acting upon a descending chair unit such that its final velocity at lower/ground level is reduced to a walking pace i.e. 0.75m/s and below.