EP0079011B1 - Rauchdetektor - Google Patents

Rauchdetektor Download PDF

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Publication number
EP0079011B1
EP0079011B1 EP82110014A EP82110014A EP0079011B1 EP 0079011 B1 EP0079011 B1 EP 0079011B1 EP 82110014 A EP82110014 A EP 82110014A EP 82110014 A EP82110014 A EP 82110014A EP 0079011 B1 EP0079011 B1 EP 0079011B1
Authority
EP
European Patent Office
Prior art keywords
radiation
smoke detector
diaphragm
receiver
solid angle
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
Application number
EP82110014A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0079011A1 (de
Inventor
Jürg Dr. sc. nat. Dipl.-Phys. Muggli
Peter Gruber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cerberus AG
Original Assignee
Cerberus AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Cerberus AG filed Critical Cerberus AG
Priority to AT82110014T priority Critical patent/ATE17061T1/de
Publication of EP0079011A1 publication Critical patent/EP0079011A1/de
Application granted granted Critical
Publication of EP0079011B1 publication Critical patent/EP0079011B1/de
Expired legal-status Critical Current

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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
    • 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
    • G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
    • G08B17/113—Constructional details

Definitions

  • the invention is based on a smoke detector operating according to the scattered radiation principle of the type defined in the preamble of claim 1.
  • Such a smoke detector is known for example from US-A-3 992 102.
  • the scattered light smoke detector described there has a cylindrical smoke chamber.
  • the light source and receiver are located approximately on the periphery of the cylinder and the sensitivity is adjusted using an adjusting screw located in the middle of the beam path at the top of a plate that prevents the receiver from being directly irradiated by the light source.
  • By turning the adjusting screw in not only the amount of light falling into the measuring room and the size of the room visible to the receiver are changed, but also (due to the scattering on the adjusting screw) the light scattered into the measuring room in the absence of smoke.
  • the smoke detector has the advantage that the amount of light emitted by the light source and the amount of light received by the receiver can be adjusted with a single setting device. At the same time, however, it must be accepted that the signal-to-noise ratio is adversely affected by an increase in the scattered light. Due to the arrangement of the adjusting screw in the middle of the beam path, the adjustment is not very
  • a smoke detector is known from CH-A-592 932, in which the radiation source emits the light in a conical shape and the receiver sees a hollow-conical solid angle.
  • the smoke detector contains an evaluation circuit which triggers an alarm when a predetermined signal level of the received scattered light is reached.
  • the smoke concentration at which the alarm is triggered is fixed.
  • the sensitivity setting for adaptation to different environmental conditions can also be achieved, for example, by changing the alarm threshold.
  • an electrical circuit arrangement for changing the sensitivity was proposed in CH-PS 468 683, in which the setting of the response threshold of a field effect transistor serving as an amplifier and threshold value detector takes place by means of a potentiometer, which is part of a voltage divider with which the source electrode is biased. Even if the setting is not made continuously with the potentiometer, but by means of a switch with which fixed resistors of different sizes are switched into the circuit, such electrical setting options are prone to failure and are not corrosion-resistant.
  • the invention has for its object to provide a smoke detector which does not have the disadvantages of the known smoke detectors mentioned and in particular to provide an optical smoke detector, the sensitivity of which can be changed in a defined manner by purely mechanical modification of optical parts.
  • the spatial angle visible by the radiation receiver is narrowed by a diaphragm which is arranged directly in front of the radiation receiver and can be displaced along the radiation direction.
  • the light falling from the radiation source onto the reference cell is narrowed by changing the opening in the aperture in front of the reference cell.
  • the radiation source 1 e.g. a semiconductor element emitting IR radiation, in the lower part of the detector.
  • the IR radiation is bundled in a hollow cone by the optics 17.
  • the central aperture 18 keeps the direct radiation away from the radiation receiver 16.
  • the reference source 12 measures and regulates the radiation emitted by the radiation source 1.
  • the aperture 3 limits the light scattered by smoke on the receiver.
  • the diaphragm 3 engages via a cam 6 in a helical groove 7 located in the cam plate 4. By turning the cam disc 4, the diaphragm 3 moves up or down in the direction of the axis due to the engagement of the cams 6 in the groove 7.
  • the amount of radiation scattered by the smoke onto the radiation receiver 16 is smaller or larger. It has been shown that a shift of the aperture 3 by a few millimeters is sufficient to make the detector less sensitive by a factor of two.
  • an opening 8 is made in the diaphragm 3, which is dimensioned such that an unimpeded radiation passage can take place in each position of the diaphragm 3.
  • this opening can also be used to mechanically change the sensitivity of the smoke detector, as described below.
  • the above-described configuration of the smoke detector according to the invention mechanically changes the solid angle visible by the radiation receiver.
  • the diaphragm 3 instead of the diaphragm 3, it is readily possible to mount a corresponding diaphragm, not shown in the figure, in such a way that the solid angle irradiated by the radiation source 1 is changed mechanically, for example as below the central aperture 18 in the vicinity of the radiation source 1.
  • a possible form for actuating the cam 4 is shown in supervision.
  • the cam disk 4 can be rotated through an elongated hole 5 in the cover 10.
  • the small depression 11 can e.g. be pushed from one stop to another. So that the height of the diaphragm 3 is more precisely defined in both positions, the groove 7 of the cam plate 4 can have a horizontal part instead of a uniformly rising shape at both end stops.
  • the groove 7 also has at least one horizontal section in the central part.
  • the distance between the depressions 11 and the length of the hole 5 are in this case coordinated with one another in such a way that the displacement of a depression 11 from one end of the hole 5 to the other allows the cam 6 to slide straight to the next horizontal section and that the next depression in particular 11 appears at the other end of the hole. If this second recess 11 is moved to the other end of the hole 5, the cam 6 slides exactly to the next horizontal section, etc.
  • a further embodiment of the mechanical adjustment device according to the invention consists of an iris diaphragm or a diaphragm ring, not shown in the figures, i.e. a rotatable disc with openings of different sizes, which are located between the central diaphragm 18 and the radiation source 1 or radiation receiver 16.
  • Another possibility of the mechanical adjustment consists in a variable covering of the reference cell 12.
  • the proportion of the light received by the radiation source 1 becomes smaller.
  • this is controlled for a stronger transmission power, as a result of which the radiation scattered on the smoke, which is received by the radiation receiver 16, becomes larger.
  • This makes the smoke detector more sensitive.
  • This can be done, for example, by changing the opening 8 in the aperture 3.
  • This change can take place by means of inserts into the opening 8 which change the cross section of the opening 8 or by means of a ring which can be rotated about the axis of the smoke detector and which contains openings of different cross sections.
  • the opening 8 can be designed such that a displacement of the diaphragm 3 at the same time causes a change in the cross section of the beam of rays falling through the opening 8 onto the reference cell 12.
  • the signal emitted by the radiation receiver 16 and dependent on the measured smoke density is fed to an evaluation circuit which, when the received signal is exceeded above a predetermined threshold value, forwards a signal to a flip-flop for emitting an alarm signal.
  • This evaluation circuit is not the subject of the present invention.

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)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Vehicle Body Suspensions (AREA)
  • Gyroscopes (AREA)
EP82110014A 1981-11-11 1982-10-29 Rauchdetektor Expired EP0079011B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82110014T ATE17061T1 (de) 1981-11-11 1982-10-29 Rauchdetektor.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH7250/81 1981-11-11
CH7250/81A CH656474A5 (de) 1981-11-11 1981-11-11 Rauchdetektor.

Publications (2)

Publication Number Publication Date
EP0079011A1 EP0079011A1 (de) 1983-05-18
EP0079011B1 true EP0079011B1 (de) 1985-12-18

Family

ID=4322193

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82110014A Expired EP0079011B1 (de) 1981-11-11 1982-10-29 Rauchdetektor

Country Status (17)

Country Link
US (1) US4524281A (no)
EP (1) EP0079011B1 (no)
JP (1) JPS5888643A (no)
AT (1) ATE17061T1 (no)
AU (1) AU556837B2 (no)
BR (1) BR8206535A (no)
CA (1) CA1208333A (no)
CH (1) CH656474A5 (no)
DE (1) DE3268057D1 (no)
DK (1) DK502482A (no)
ES (1) ES8309022A1 (no)
FI (1) FI75438C (no)
IL (1) IL67159A0 (no)
NO (1) NO157156C (no)
NZ (1) NZ202364A (no)
YU (1) YU252282A (no)
ZA (1) ZA828096B (no)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS626144A (ja) * 1985-07-03 1987-01-13 Nittan Co Ltd 光電式煙感知器
US4814748A (en) * 1987-11-09 1989-03-21 Southwest Laboratories, Inc. Temporary desensitization technique for smoke alarms
GB2259763B (en) * 1991-09-20 1995-05-31 Hochiki Co Fire alarm system
ITTO20070355A1 (it) * 2007-05-18 2008-11-19 Elkron Spa Dispositivo e metodo per rilevare fumo
GB2537940B (en) 2015-05-01 2018-02-14 Thorn Security Fire detector drift compensation

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB966867A (en) * 1961-01-05 1964-08-19 Pyrene Co Ltd Improvements relating to smoke indicators
GB1172354A (en) * 1966-02-16 1969-11-26 Pyrene Co Ltd Improvements relating to Smoke Detectors
JPS4418923Y1 (no) * 1966-09-16 1969-08-14
US3868184A (en) * 1973-07-25 1975-02-25 Electro Signal Lab Optical smoke detector with light scattering test device
JPS50134172A (no) * 1974-04-17 1975-10-24
US3985453A (en) * 1974-07-19 1976-10-12 Matsushita Electric Works, Ltd. Light scattering type smoke detector
US4011458A (en) * 1975-10-09 1977-03-08 Pyrotector, Incorporated Photoelectric detector with light source intensity regulation
FR2357888A1 (fr) * 1976-04-01 1978-02-03 Cerberus Ag Detecteur de fumee
US4216377A (en) * 1977-06-27 1980-08-05 Nittan Company, Limited Light scattering smoke detector
US4269510A (en) * 1978-12-21 1981-05-26 Cerberus Ag Smoke detector
US4430646A (en) * 1980-12-31 1984-02-07 American District Telegraph Company Forward scatter smoke detector

Also Published As

Publication number Publication date
ATE17061T1 (de) 1986-01-15
FI823838A0 (fi) 1982-11-09
FI823838L (fi) 1983-05-12
YU252282A (en) 1985-10-31
IL67159A0 (en) 1983-03-31
DK502482A (da) 1983-05-12
NO157156C (no) 1988-01-27
NO823754L (no) 1983-05-13
NZ202364A (en) 1986-04-11
NO157156B (no) 1987-10-19
BR8206535A (pt) 1983-09-27
US4524281A (en) 1985-06-18
AU9017582A (en) 1983-05-19
AU556837B2 (en) 1986-11-20
ES517588A0 (es) 1983-10-01
CA1208333A (en) 1986-07-22
FI75438C (fi) 1988-06-09
CH656474A5 (de) 1986-06-30
ES8309022A1 (es) 1983-10-01
FI75438B (fi) 1988-02-29
EP0079011A1 (de) 1983-05-18
DE3268057D1 (en) 1986-01-30
ZA828096B (en) 1983-09-28
JPS5888643A (ja) 1983-05-26

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