IL42930A - Fire alarms - Google Patents
Fire alarmsInfo
- Publication number
- IL42930A IL42930A IL42930A IL4293073A IL42930A IL 42930 A IL42930 A IL 42930A IL 42930 A IL42930 A IL 42930A IL 4293073 A IL4293073 A IL 4293073A IL 42930 A IL42930 A IL 42930A
- Authority
- IL
- Israel
- Prior art keywords
- radiation
- fire
- accordance
- detecting apparatus
- frequency
- Prior art date
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
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)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Claims (10)
1. Fire-detec ing apparatus comprising: a source of radiation including a solid-state emitter emitting a beam of radiation in a series of pulses; radiation-receiving nieans positioned to receive radiation which has passed through an intervening gaseous medium from the said source and including a device sensitive to the received radiation to produce a corresponding electric signal, the beam of radiation, where incident on the radiation-receiving means, overlapping the radiation-receiving means around the vhole of its perimeter; a frequency-selective circuit for selecting from the output of the radiation-sensitive device a pulse signal resulting from the pulses of radiation from the said source; and an alarm circuit connected to receive this pulse signal and responsive to a variation of the amplitude of the pulse signal at a frequency of not less than 1 Hz and resulting from variations of the refractive index of the gaseous medium due to the heat of the fire.
2. Fire-detecting apparatus in accordance v/ith Claim 1, in which the source of radiation is an infra-red light source of the gallium arsenide kind.
3. Fire-detecting apparatus in accordance With Claim 1 or 2 , in which the radiation-sensi ive device is a pho o-transis or.
4. Fire-detecting apparatus in accordance with Claiiu 3 , including means whereby the photo-transistor is given a constant forward bias.
5. Fire-detecting apparatus in accordance with claim 4, in which the forward biasing means is a subsidiary source of radiation, located at the radiation-receiving means, and arranged to irradiate the photo-transistor at a substantially constant level,
6. Fire-detecting apparatus in accordance with any one of claims 1-5, in which the frequency response of the frequency-selective circuit is substantially greater than the pulse repetition frequency of the emitted pulses of radia ion,
7. Fire-detecting apparatus in accordance with any one of claims 1-6, in which the alarm circuit includes a frequency-selective audio frequency circuit.
8. Fire-detecting apparatus in accordance with claim 7, in which the maximum response of the said audio frequency circuit occurs in the frequency range 2 Hz to 25 Hz.
9. Fire-detecting apparatus in accordance with any one of claims 1-8, including a further alarm circuit responsive to a reduction in the amplitude of the said pulse signal indicative of at least a partial obscuration of the said emitted radiation.
10. Fire-detecting apparatus in accordance with claim 1, substantially as herein described with reference to Figure 1 of the accompanying drawings. P.0. Box 331 16 , Tel- Λ ν ι v A tt o rn e y s f o r Applicant
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3763372A GB1405615A (en) | 1972-08-11 | 1972-08-11 | Fire alarms |
| GB5258772 | 1972-11-14 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IL42930A0 IL42930A0 (en) | 1973-11-28 |
| IL42930A true IL42930A (en) | 1976-10-31 |
Family
ID=26263518
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IL42930A IL42930A (en) | 1972-08-11 | 1973-08-08 | Fire alarms |
Country Status (17)
| Country | Link |
|---|---|
| JP (1) | JPS49132998A (en) |
| AT (1) | AT347300B (en) |
| AU (1) | AU476368B2 (en) |
| CH (1) | CH560434A5 (en) |
| DD (1) | DD107157A5 (en) |
| DE (1) | DE2340041C2 (en) |
| DK (1) | DK144255C (en) |
| ES (1) | ES417739A1 (en) |
| FR (1) | FR2195813B3 (en) |
| GB (1) | GB1405615A (en) |
| HK (1) | HK55376A (en) |
| IL (1) | IL42930A (en) |
| IT (1) | IT990203B (en) |
| MY (1) | MY7600243A (en) |
| NL (1) | NL7311010A (en) |
| NO (1) | NO132564C (en) |
| SE (1) | SE383793B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE7604502L (en) * | 1976-04-15 | 1977-10-16 | Ericsson Telefon Ab L M | OPTICAL FIRE DETECTOR |
| SE395554B (en) * | 1976-09-01 | 1977-08-15 | Ericsson Telefon Ab L M | OPTICAL FIRE DETECTOR |
| EP0022438B1 (en) * | 1979-07-13 | 1983-07-20 | Securiton AG | Method for detecting aerosols in air of a control zone and apparatus for its performing |
| JPS5631625A (en) * | 1979-08-24 | 1981-03-31 | Hochiki Corp | Smoke detector of photoelectronic type |
| JPS57140925A (en) * | 1981-02-24 | 1982-08-31 | Fuji Heavy Ind Ltd | Detection of clutch overheat |
| AU556490B2 (en) * | 1982-07-29 | 1986-11-06 | Kerr-Mcgee Corp. | Production monitoring system |
| EP0145189B1 (en) * | 1983-10-21 | 1990-08-08 | COLE, Martin Terence | Improvements relating to smoke detection apparatus |
| DE102004004098B3 (en) * | 2004-01-27 | 2005-09-01 | Wagner Alarm- Und Sicherungssysteme Gmbh | Method for evaluating a scattered light signal and scattered light detector for carrying out the method |
| CN108510701B (en) * | 2018-03-20 | 2019-11-22 | 深圳市泰和安科技有限公司 | A kind of intelligent smog alarm method, apparatus and system |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE455987C (en) * | 1924-04-11 | 1928-02-11 | John Joseph Dowling | Device for displaying light fluctuations through a light-sensitive cell and a highly sensitive relay |
| DE1024851B (en) * | 1953-05-04 | 1958-02-20 | Electronics Corp America | Display device for flames |
| JPS4429154Y1 (en) * | 1967-04-20 | 1969-12-03 | ||
| GB1278205A (en) * | 1970-02-11 | 1972-06-21 | Shorrock Develpoments Ltd | Smoke detecting device |
| DE2023463B1 (en) * | 1970-05-13 | 1971-12-30 | Preussag Ag Feuerschutz | Optical smoke detector |
-
1972
- 1972-08-11 GB GB3763372A patent/GB1405615A/en not_active Expired
-
1973
- 1973-08-06 NO NO3132/73A patent/NO132564C/no unknown
- 1973-08-08 DE DE2340041A patent/DE2340041C2/en not_active Expired
- 1973-08-08 IL IL42930A patent/IL42930A/en unknown
- 1973-08-08 AU AU59013/73A patent/AU476368B2/en not_active Expired
- 1973-08-09 NL NL7311010A patent/NL7311010A/xx not_active Application Discontinuation
- 1973-08-09 IT IT51932/73A patent/IT990203B/en active
- 1973-08-10 SE SE7310965A patent/SE383793B/en unknown
- 1973-08-10 DK DK439773A patent/DK144255C/en not_active IP Right Cessation
- 1973-08-10 FR FR7329293A patent/FR2195813B3/fr not_active Expired
- 1973-08-10 DD DD172840A patent/DD107157A5/xx unknown
- 1973-08-10 CH CH1157773A patent/CH560434A5/xx not_active IP Right Cessation
- 1973-08-10 ES ES417739A patent/ES417739A1/en not_active Expired
- 1973-08-11 JP JP48089688A patent/JPS49132998A/ja active Pending
- 1973-08-13 AT AT708673A patent/AT347300B/en not_active IP Right Cessation
-
1976
- 1976-09-08 HK HK553/76*UA patent/HK55376A/en unknown
- 1976-12-31 MY MY1976243A patent/MY7600243A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| CH560434A5 (en) | 1975-03-27 |
| HK55376A (en) | 1976-09-17 |
| MY7600243A (en) | 1976-12-31 |
| ES417739A1 (en) | 1976-02-16 |
| AT347300B (en) | 1978-12-27 |
| FR2195813B3 (en) | 1975-10-31 |
| NO132564B (en) | 1975-08-18 |
| ATA708673A (en) | 1978-04-15 |
| IT990203B (en) | 1975-06-20 |
| DK144255B (en) | 1982-01-25 |
| IL42930A0 (en) | 1973-11-28 |
| NL7311010A (en) | 1974-02-13 |
| GB1405615A (en) | 1975-09-10 |
| AU476368B2 (en) | 1976-09-16 |
| DE2340041A1 (en) | 1974-04-04 |
| DE2340041C2 (en) | 1984-11-29 |
| DK144255C (en) | 1982-08-16 |
| NO132564C (en) | 1975-11-26 |
| AU5901373A (en) | 1975-02-13 |
| DD107157A5 (en) | 1974-07-12 |
| SE383793B (en) | 1976-03-29 |
| JPS49132998A (en) | 1974-12-20 |
| FR2195813A1 (en) | 1974-03-08 |
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