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Prevention of Faulty Equipment from Emitting Smoke

IP.com Disclosure Number: IPCOM000106899D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 3 page(s) / 92K

Publishing Venue

IBM

Related People

Eagle, DJ: AUTHOR [+2]

Abstract

Described is a method that eliminates smoke and fire hazard from electrical equipment. The technique detects any smoke arising within a unit and then shuts off mains power to prevent the initial smoldering from sparking ignition. It is applicable for any electrical domestic or office equipment.

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Prevention of Faulty Equipment from Emitting Smoke

       Described is a method that eliminates smoke and fire
hazard from electrical equipment.  The technique detects any smoke
arising within a unit and then shuts off mains power to prevent the
initial smoldering from sparking ignition.  It is applicable for any
electrical domestic or office equipment.

      Smoke or its smell coming from electrical equipment and noticed
by personnel usually provokes a panic state often leading to a total
mistrust of the equipment or its replacement with a bad impression of
the equipment supplier. At its worst, where a fire develops, there is
obvious risk of injury.  Resultant bad publicity can have a profound
effect in public confidence and subsequent sales.  A device which
considerably reduces the risk of a faulty equipment emitting smoke,
whatever the cause, before contact breakers or fuses take effect, is
highly desirable for safety and marketing.

      This article proposes the use of a simple low-cost smoke
detection unit to drive a switch that powers down equipment if smoke
is detected.  This action should be latching to prevent cycles of
smoking and power down, etc. The concept is shown in Fig. 1 which
depicts a smoke-detecting element and switching element in series
with the power lines into the equipment.  The detector and control
circuit are powered from the mains, so switching the equipment off
will reset the circuit.  An alternative solution would be to put the
detector/switch block between the mains and the equipment power
switch.  This has the advantage that the unit cannot be powered on
again unless the equipment is unplugged but the disadvantage is that
the detection circuitry and its associated power supply are left
powered on continually which leads to a slight fire risk by itself.
A further feature shown in Fig. 1 is an optional audible alarm.  This
could be used to alert personnel in the vicinity to the fault.
Another feature would be that the detector would also provid...