Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1993-02-16
1995-01-24
Swann, Glen
Communications: electrical
Condition responsive indicating system
Specific condition
340586, 340590, 340593, G08B 1706
Patent
active
053845625
ABSTRACT:
A heat-sensitive alarm trigger is used to set off a fire alarm system having an alarm circuit with a rated trigger resistance. The alarm circuit is triggered when a resistance across two sensor leads, between which the alarm trigger is connected, falls below the rated trigger resistance. The heat-sensitive alarm trigger comprises a laminate structure which includes an optionally perforated first electrode layer and a second electrode layer. A barrier material layer which is disposed between the two electrode layers has a resistance above the rated trigger resistance. A layer of hydrated material is disposed on the perforated electrode layer. When the hydrated material is heated above a given alarm trigger temperature, moisture is given off through the holes in the first electrode and, as a result, the barrier layer becomes sufficiently conductive so as to lower a resistance across the electrodes to below the rated trigger resistance. In the alternative, the hydrated layer is the barrier layer sandwiched between the electrodes. When the barrier layer reaches a given trigger temperature, its resistance falls below the rated trigger resistance, and the alarm circuit is triggered.
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Publication Product Data; DP-90-3046 "Koroseal Wallcoverings" (formerly BF Goodrich Wallcoverings, 2 pages).
Greenberg Laurence A.
Lerner Herbert L.
Swann Glen
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