FIRE DETECTOR FOR TUNNEL

Japanese Patent JP3261159

B2

PURPOSE: To extend time until detection is disabled by dirt on the window of the fire detector by performing adjustment so that corresponding to the compared result so that an output from a level adjusting means can be turned to a prescribed state to a reference level when a light source unit is operated.
CONSTITUTION: In a casing 5, lamps 9 and 11 for check are provided corresponding to infrared photodetectors 2 and 3. Respective beams from the lamps 9 and 11 are inputted to the infrared photodetectors 2 and 3 in an initial state in which light transmitting glass 7, 8, 10 and 12 is not made dirty, and output signals E and F are respectively stored in storage parts 26 and 27 as the reference level. When the light transmitting glass 7 and 8 is made dirty with the exhausted gas of vehicles, the beams inputted to the photodetectors 2 and 3 are attenuated and the levels of the respective output signals E and F from variable gain amplifiers 21 and 22, those levels are compared with the reference level stored in the storage parts 26 and 27 by comparator parts 28 and 29. The compared result is sent to gain control parts 31, 32 and here, the gains of the amplifiers 21, 22 are controlled so that the levels of the output signals E and F can be equalized to the reference level.

JP6068211	The sensor test system of fire information equipment
JP2001100678	LUMINAIRE FOR EMERGENCY EXIT SIGN SYSTEM
JP7302980	transmitter

Masanori Hirasawa

JP14205392A

February 25, 2002

May 08, 1992

Click for automatic bibliography generation  

International Technology Development Co., Ltd.

G08B17/00; G08B17/12; (IPC1-7): G08B17/12; G08B17/00

JP595398A
JP4846295A
JP5485786A
JP61178621A
JP52156585U
JP6092394U

Masatoshi Takano

Previous Patent: DEVICE CONVEYOR FOR IC HANDLER

Next Patent: FUNCTIONAL THIN FILM CONTAINING GUANIDINIUM DERIVATIVE AND NUCLEIC ACID BASE DERIVATIVE