GB1490866A - Light responsive detectors - Google Patents
Light responsive detectorsInfo
- Publication number
- GB1490866A GB1490866A GB45706/74A GB4570674A GB1490866A GB 1490866 A GB1490866 A GB 1490866A GB 45706/74 A GB45706/74 A GB 45706/74A GB 4570674 A GB4570674 A GB 4570674A GB 1490866 A GB1490866 A GB 1490866A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pulse
- detector
- light
- threshold circuit
- flip
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
- G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
-
- 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
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Fire-Detection Mechanisms (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
1490866 Smoke detectors CHLORIDE BATTERIJEN BV 22 Oct 1974 [26 Nov 1973 8 March 1974] 45706/74 Heading G1A A device responsive to a predetermined situation e.g. the presence of smoke, has a pulsed light source and a light detector whose output is connected to a threshold circuit such that a signal is delivered to an alarm only if the detector output exceeds a given level. The light source is pulsed to that it is typically emitting only for 20Á secs every 2 secs, and the level detector is also energized only during the time the source is pulsed; this reduces the likelihood of external light flashes affecting the device. In Fig. 1 the source is an LED, pulsed as above by a power supply P. The pulse from P also activates the threshold circuit L and operates switch S1 to disconnect that circuit's input from earth. The light emitted by the source is scattered by any smoke present to a detector C; the detector pulse passes via capacitor F to amplifier A and thence to the threshold circuit L. The capacitor prevents slow changes in ambient light being amplified. The threshold circuit compares the amplified pulse with a level pre-set by R2, and delivers a SET signal to flip-flop FF if that level is exceeded. At the start of the next power supply pulse the flip-flop is reset by a signal from differentiator D. The flip-flop can either activate an alarm K directly, or, as shown in Fig. 1, via an integrator T whose time constant is such that two consecutive pulses are required from the flip-flop before the alarm is activated. Power supplies: it is desirable to isolate the detector circuitry from the light source power supply. In Fig. 4 the power is supplied on line V1, and the pulse supply P activates a switch S2 as well as the light source and threshold circuit. During light emission the circuitry thus receives its power from a capacitor F1 which is recharged via R when S2 is closed at the end of each pulse. This use of a switch may be combined with or replaced by the use of smoothing chokes feeding capacitors F1, F2, as in Fig. 5 (not shown), or by resistors and Zener diodes feeding those capacitors, as in Fig. 6 (not shown).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US41920673A | 1973-11-26 | 1973-11-26 | |
| US449362A US3917956A (en) | 1974-03-08 | 1974-03-08 | Smoke detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1490866A true GB1490866A (en) | 1977-11-02 |
Family
ID=27024396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB45706/74A Expired GB1490866A (en) | 1973-11-26 | 1974-10-22 | Light responsive detectors |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS50114275A (en) |
| BR (1) | BR7408707D0 (en) |
| CA (1) | CA1056931A (en) |
| CH (2) | CH580848A5 (en) |
| CS (1) | CS186786B2 (en) |
| DE (2) | DE2462876C2 (en) |
| FR (1) | FR2254024B3 (en) |
| GB (1) | GB1490866A (en) |
| IL (1) | IL45331A (en) |
| IN (1) | IN143206B (en) |
| NL (1) | NL7410079A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114401760A (en) * | 2019-05-23 | 2022-04-26 | 北门科技股份有限公司 | System and method for smoke removal in a gas recirculation system |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5354000A (en) * | 1976-10-26 | 1978-05-16 | Matsushita Electric Works Ltd | Detection signal processing circuit of photoelectric type smoke detectors |
| US4125779A (en) * | 1977-07-13 | 1978-11-14 | Chloride, Incorporated | Smoke detector |
| CH638331A5 (en) * | 1979-02-22 | 1983-09-15 | Cerberus Ag | SMOKE DETECTOR. |
| DE3063643D1 (en) * | 1979-02-26 | 1983-07-14 | Cerberus Ag | Fire detector using pulsed radiation |
| BE881812A (en) * | 1979-12-17 | 1980-06-16 | Cerberus Ag | NOTIFICATION SYSTEM |
| JPS5716956U (en) * | 1980-06-30 | 1982-01-28 | ||
| JPS6014398B2 (en) * | 1981-03-18 | 1985-04-12 | ホーチキ株式会社 | photoelectric smoke detector |
| EP0145189B1 (en) * | 1983-10-21 | 1990-08-08 | COLE, Martin Terence | Improvements relating to smoke detection apparatus |
| JPS6151U (en) * | 1985-05-17 | 1986-01-06 | 京セラ株式会社 | Photoelectric smoke detection alarm device |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH417405A (en) * | 1964-07-14 | 1966-07-15 | Cerberus Ag Werk Fuer Elektron | Device for the detection of aerosols in air |
| US3382762A (en) * | 1967-02-21 | 1968-05-14 | Alfred W. Vasel | Smoke detecting device |
| US3555532A (en) * | 1968-10-29 | 1971-01-12 | Graham Stuart Corp | Vapor or particle detection device |
| GB1278205A (en) * | 1970-02-11 | 1972-06-21 | Shorrock Develpoments Ltd | Smoke detecting device |
| CH520990A (en) * | 1970-12-21 | 1972-03-31 | Cerberus Ag | Smoke detector |
-
1974
- 1974-07-22 IL IL45331A patent/IL45331A/en unknown
- 1974-07-26 NL NL7410079A patent/NL7410079A/en not_active Application Discontinuation
- 1974-08-01 IN IN1715/CAL/1974A patent/IN143206B/en unknown
- 1974-08-07 CH CH1079974A patent/CH580848A5/xx not_active IP Right Cessation
- 1974-08-07 CH CH560576A patent/CH599645A5/xx not_active IP Right Cessation
- 1974-08-16 JP JP49094109A patent/JPS50114275A/ja active Pending
- 1974-08-19 CA CA207,336A patent/CA1056931A/en not_active Expired
- 1974-08-22 CS CS7400005834A patent/CS186786B2/en unknown
- 1974-10-09 DE DE2462876A patent/DE2462876C2/en not_active Expired
- 1974-10-09 DE DE2448195A patent/DE2448195C2/en not_active Expired
- 1974-10-18 BR BR8707/74A patent/BR7408707D0/en unknown
- 1974-10-22 GB GB45706/74A patent/GB1490866A/en not_active Expired
-
1975
- 1975-01-31 FR FR7503156A patent/FR2254024B3/fr not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114401760A (en) * | 2019-05-23 | 2022-04-26 | 北门科技股份有限公司 | System and method for smoke removal in a gas recirculation system |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2254024A1 (en) | 1975-07-04 |
| CH580848A5 (en) | 1976-10-15 |
| DE2462876C2 (en) | 1983-06-09 |
| CH599645A5 (en) | 1978-05-31 |
| CS186786B2 (en) | 1978-12-29 |
| IN143206B (en) | 1977-10-15 |
| NL7410079A (en) | 1975-05-28 |
| IL45331A0 (en) | 1974-10-22 |
| BR7408707D0 (en) | 1975-08-26 |
| FR2254024B3 (en) | 1979-02-02 |
| AU7330074A (en) | 1976-03-18 |
| DE2448195A1 (en) | 1975-05-28 |
| DE2448195C2 (en) | 1984-08-23 |
| CA1056931A (en) | 1979-06-19 |
| IL45331A (en) | 1977-12-30 |
| JPS50114275A (en) | 1975-09-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |