JPS55134344A - Optical fire alarm system - Google Patents
Optical fire alarm systemInfo
- Publication number
- JPS55134344A JPS55134344A JP4201279A JP4201279A JPS55134344A JP S55134344 A JPS55134344 A JP S55134344A JP 4201279 A JP4201279 A JP 4201279A JP 4201279 A JP4201279 A JP 4201279A JP S55134344 A JPS55134344 A JP S55134344A
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- amplifier
- pulse signal
- modulated pulse
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
- G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
- G08B17/107—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device for detecting light-scattering due to smoke
Landscapes
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fire-Detection Mechanisms (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
PURPOSE:To prevent the malfunction due to both an external light and an electrical noise removing affection to the frequency, which is caused by a change of temperature, by controlling both an oscillating circuit of a modulating oscillator and a tuning circuit of a selective amplifier by means of the same mechanical vibrator. CONSTITUTION:A fixed frequency oscillator 2 is operated by a pulse signal from the square wave oscillator 1 to provide a modulated pulse signal of a frequency f1 that is determined by the mechanical vibrator 3, a modulated pulse light ray is emitted from the light emission element 4. When no smoke is present in the room, the light receiver element 5 provides no output. On the other hand, when smoke enters the room due to a fire, the light ray from the element 4 is scattered, a modulated pulse signal of a frequency f1 is produced by the element 5 and is fed to the selective amplifier 8 through the preamplifier 6 and the delay circuit 7. The tuned frequency of the amplifier 8 is controlled by the vibrator 3, and when the output level of the amplifier 8 reaches a fixed value, a fire alarm is provided to the output of the device through the switching circuit 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4201279A JPS5931759B2 (en) | 1979-04-09 | 1979-04-09 | optical fire detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4201279A JPS5931759B2 (en) | 1979-04-09 | 1979-04-09 | optical fire detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55134344A true JPS55134344A (en) | 1980-10-20 |
| JPS5931759B2 JPS5931759B2 (en) | 1984-08-03 |
Family
ID=12624260
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4201279A Expired JPS5931759B2 (en) | 1979-04-09 | 1979-04-09 | optical fire detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5931759B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6920945B2 (en) * | 2017-09-26 | 2021-08-18 | 能美防災株式会社 | Smoke detector and fire receiver |
-
1979
- 1979-04-09 JP JP4201279A patent/JPS5931759B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5931759B2 (en) | 1984-08-03 |
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