Patent Application
20090139668
This invention relates to a fire curtain system of the kind adapted to be stored horizontally in a rolled condition at an elevated location, and in a fire situation to be deployed by unrolling either automatically by a signal from a fire alarm system, or by manual intervention.
Such fire curtains are required to be of a fabric capable of enduring prescribed temperatures for a prescribed period of time (typically 1000° C. for four hours) and are retained in their stored condition usually by a mains supply powered electromagnetic means which when subjected to power interruption either by a signal from a fire alarm system or by mains failure as a result of the emergency situation or by backup failure, permits failsafe, gravity deployment of the curtains (in contrast to a powered drop system) usually aided by a bottom bar or other weight device attached to a lower edge of the curtain. Deployment is restricted to a relatively slow speed e.g. 100 mm/sec to avoid injury to any persons beneath the curtain. However, it is not uncommon during or after deployment of fire curtains for a person to find himself on the fire side of a curtain rather than the safe side, which leads to difficulties in effecting escape beyond the barrier provided by the curtain. To deal with this problem the provision of doors or flaps defeats the fundamental objective of a fire curtain, and consequently it has been known to provide a retraction/rewind system to raise a fire curtain temporarily to an escape height to provide an escape passage for trapped persons beneath the lower edge of the curtain, but retraction has been at the same relatively low speed of deployment.
A basic object of the present invention is to provide an improved fire curtain system.
According to the present invention there is provided a fire curtain system comprising:—
The invention thus provides a fire curtain system which, after deployment to the floor, or during deployment to the floor, may be rapidly raised to an escape height by manual intervention of any person trapped on the fire side of the curtain by that person operating the override button or switch, rather than the trapped person having to await retraction/rewind being initiated from a remote source, or attempting to escape underneath the curtain or around a lateral edge of the curtain.
The push button(s) or switch(es), is/are provided at a prominent location(s) on a structure of a building in which the fire curtain system is installed.
Operation of the button(s) or switch(es) connects the electrical supply to the rewind motor which rewinds the curtain at the relatively high speed of circa 400 to 500 mm/sec.
The push button(s) or switch(es) is/are of a type where on release the circuit is automatically opened switching off the supply to the rewind motor and causing the curtain to commence deployment at the controlled descent speed in the region of 100 to 150 mm/sec.
The control system includes a group control panel which interfaces with the alarm system and provides AC/DC voltage, and by a motor control circuit which rectified the AC voltage, regulates the power supplied to the motor and controls the speed of descent.
Protected electrical leads extend from the switches or buttons to the control system.
The curtain is housed in a headbox.
The headbox is of steel e.g. 1.2 mm galvanised steel, rated at the same temperature as the fabric of the curtain.
The headbox houses the electric motor to effect partial or full retraction or rewinding of the curtain.
The curtain is wound onto a roller of circular section.
The roller comprises a steel tube.
Within the tube, the electric motor and a speed reduction gearbox are incorporated.
A motor control circuit, housed in a steel enclosure, is mounted at an end of the headbox adjacent the motor.
The curtain is of woven glass fibre cloth with a wire reinforcement.
The curtain is retained in its non-deployed position by its associated motor operating at low voltage.
One example of fire curtain system in accordance with the invention is shown diagrammatically in the accompanying drawings, in which:—
A fire curtain system comprises a fire-resistant fabric curtain 1 adapted to be rolled and stored on a steel tube 2 rotatable about an axis 3, the steel tube 2 being installed at an elevated location such that, in a test or a fire situation, the tube 2 is rotatable to unwind the curtain 1, and after test completion, or emergency termination, to be re-wound by reverse rotation of the tube 2.
The tube 2 is mounted to support structure by means of two spaced-apart brackets 4 each having a pocket 5, one pocket being for reception of a stub shaft 6 of a bearing assembly 7 adapted to be fitted into one end of the tube 2, and secured by rivets 8. Into the other end of the tube 2 is inserted an electric motor assembly 9 having a stub shaft 10 for insertion in, and reaction against, the sides of the pocket 5 of the other bracket 4. Electrical leads 11 extend from the motor assembly 9.
Both the bearing assembly 7 and the motor assembly 9 have a longitudinal groove 12 to receive a welded seam (not shown) inside the tube 2. A bar 14 is inserted into a pocket of the curtain 1 and secured by means of a series of screws 15, whilst the other end of the curtain 1 is attached to a bottom bar 16, the weight of which assists in deployment of the curtain 1 under gravity, either in a test mode or an alarm mode.
Adjacent an edge 17 of the curtain 1, or the endmost curtain if several are arrayed end to end for a particular area requiring fire curtains, is a support structure 18, brickwork being indicated, but a steel column, or concrete wall etc would also be suitable, on which structure 18 is mounted a manually operable push button 19 with electrical leads 20 housed in a conduit 21.
The rolled up curtain 1 and steel tube 2 are conventionally housed in a rectangular head box (not shown) and a control system for controlling the various functions of the curtain are conventionally housed in a steel enclosure (not shown) also mounted in an elevated location adjacent the motor end of the head box, to which enclosure the leads 20 from the push button 19 extend.
Conventionally, the tube 2 is prevented from rotation under the weight of the bottom bar 16 and hence is prevented from unwinding the curtain to its deployed test or emergency position by an electromagnetic clutch (not shown). However, the clutch is released e.g. by cutting, or loss of electrical power in either a test mode or an emergency mode, whereby the tube 2 is released and the curtain 1 is permitted to fall, under gravity at say 100 to 150 mm/sec.
Should a person find himself on the “fire” side of the curtain 1, then pushing the button 18 activates the control system to override deployment and to activate the motor assembly 9 to retract, or rewind, the curtain 2 at a relatively high speed e.g. 400-500 mm/sec temporarily, to provide an escape route beneath the bottom bar.
As shown in
