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US 4,162,489 AGranted
Fire alarm system comprising a plurality of alarms which may be operated by way of an alarm loop
AssigneeSiemens Aktiengesellschaft
InventorsPeer Thilo, Otto W. Moser
Life of this patent
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Abstract
A fire alarm system comprises a plurality of alarms which may be operated via an alarm loop and which, being subject to selective interrogation, each alarm transmits an analog value of a particular characteristic of a fire to a central control, the analog value being tapped from a detector for that characteristic. Each alarm comprises an alarm circuit which has a load resistor which can be connected in parallel to the alarm loop by means of a timing element and which amplifies the current which characterizes the alarm at the instant of interrogation.
Claims7
A fire alarm system comprising:
- a plurality of alarm circuits which are connectible in an
- alarm loop for interrogation;
- and
- a central control connected to said alarm loop including means for applying operating power to said alarm circuits and means for receiving signals generated by said alarm circuits,
- each of said alarm circuits comprising:
- a detector for detecting a predetermined characteristic of a fire and generating a representative first signal, signaling means connected to said detector and operated by said first signal to amplify and place the same as an amplified second signal on said loop,
- said signaling means including a timing circuit having a load resistance connected in parallel to said loop by said signaling means.
4 more elements
Dependencies are inferred from the claim text.