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出願の表示

1. US20100259396 - Fire alarm system

官庁 アメリカ合衆国
出願番号 12682300
出願日 21.10.2008
公開番号 20100259396
公開日 14.10.2010
特許番号 08519854
特許付与日 27.08.2013
公報種別 B2
IPC
G08B 17/12
G物理学
08信号
B信号または呼出し装置;指令発信装置;警報装置
17火災警報;爆発に応答する警報
12輻射線または粒子,例.赤外線またはイオンの存在によって動作するもの
出願人 Watabe Yoshifumi
Panasonic Corporation
Honda Yoshiaki
Hayashi Masanori
Takada Yuji
Nishikawa Takayuki
発明者 Watabe Yoshifumi
Honda Yoshiaki
Hayashi Masanori
Takada Yuji
Nishikawa Takayuki
代理人 McDermott Will & Emery LLP
発明の名称
(EN) Fire alarm system
要約
(EN)

A fire alarm system, determining existence or nonexistence of a fire by using an ultrasound wave, comprises a sound wave generator and a sound wave detector to detect sound waves propagated through two propagation paths having different lengths each other. The system comprises a calculation means for calculating a pressure ratio between a first sound pressure, which is a sound pressure of a sound wave propagated through a first propagation path, and a second sound pressure, which is a sound pressure of a sound wave propagated through a second propagation path, and a smoke density estimator. The smoke density estimator calculates a change ratio between the pressure ratio calculated by the calculation means and a predetermined standard pressure ratio, and determines a smoke density from the change ratio based on a predetermined relational expression describing the relation between the change ratio and the smoke density, and determines existence of a fire when the smoke density exceeds a predetermined threshold.