US3868184A - Optical smoke detector with light scattering test device - Google Patents

Optical smoke detector with light scattering test device Download PDF

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Publication number
US3868184A
US3868184A US382521A US38252173A US3868184A US 3868184 A US3868184 A US 3868184A US 382521 A US382521 A US 382521A US 38252173 A US38252173 A US 38252173A US 3868184 A US3868184 A US 3868184A
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US
United States
Prior art keywords
light
particle
lamp
path
housing
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 - Lifetime
Application number
US382521A
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English (en)
Inventor
Angelo August Marsocci
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Sentrol Inc
Original Assignee
Electro Signal Lab Inc
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 Electro Signal Lab Inc filed Critical Electro Signal Lab Inc
Priority to US382521A priority Critical patent/US3868184A/en
Priority to GB5050773A priority patent/GB1434658A/en
Priority to CA184,698A priority patent/CA1014637A/en
Priority to DE2355784A priority patent/DE2355784C2/de
Priority to JP12714673A priority patent/JPS5711013B2/ja
Priority to FR7341044A priority patent/FR2239168A5/fr
Priority to IT9693/73A priority patent/IT1000974B/it
Application granted granted Critical
Publication of US3868184A publication Critical patent/US3868184A/en
Assigned to SENTROL ACQUISITION CORP. A DE CORPORATION reassignment SENTROL ACQUISITION CORP. A DE CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ELECTRO SIGNAL LAB, INC., A CORPORATION OF DE
Anticipated expiration legal-status Critical
Assigned to SENTROL, INC. A CORP. OF OREGON reassignment SENTROL, INC. A CORP. OF OREGON MERGER (SEE DOCUMENT FOR DETAILS). EFFECTIVE ON 12/31/1991 OREGON Assignors: SENTROL ACQUISITION CORP. A CORP. OF DELAWARE (MERGED INTO)
Expired - Lifetime legal-status Critical Current

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    • 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
    • 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
    • G01N21/4785—Standardising light scatter apparatus; Standards therefor
    • 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
    • G08B17/11—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

  • ABSTRACT An optical smoke and like particle detector housing in which light from a lamp is protected along one axis and scattered by particles along a second axis to a photocell has a particle simulating device for testing the operativeness of the cell and its associated alarm circuit.
  • the particle simulating device comprises a thin wire mounted on a bell crank manually operated outside the detector housing to swing the wire through the detection zone at the intersection of the lamp and photocell axes so as to scatter light from the lamp to the cell in the same way and amount as particles in the zone.
  • the alarm point (in smoke density percentage) of the detector will drift over a period of time.
  • the drift usually being upward in percentage corresponding to a decrease in sensitivity of the detector.
  • the detector ceases to be responsive to smoke densities in excess of 10 percent for example lethal quantities of smoke and accompanying toxic gases can accumulate and the causative fire may spread without warning.
  • smoke detectors are expected to function properly without attention and years may pass during which the detector is allowed to drift to an inadequately sensitive state.
  • one object of the present invention is to provide a simple inexpensive test, not merely of the operativeness of a particular detector component such as the photocell, but rather of the ultimate function of the detector, namely to alarm in response to a predetermined smoke density.
  • a further object is to provide a test which is independent of the position of the filament in the exciter lamp and of consequent variations of the location of the light path in the dark chamber.
  • an optical particle detector comprises a housing enclosing a dark chamber; a lamp mounted on the housing to direct on a path into the chamber; a photosensitive device on the housing viewing the light path and responsive to light scattered by particles in the path; and a particle simulating member movably mounted on the housing and having a portion movable through the light path at a zone scattering a calibrated intensity of light to the device independently of the presence and accumulation of particles between the lamp and device.
  • FIG. I is a plan view shown partly in section of an optical smoke detector with a testing device according to the invention.
  • FIG. 2 is a section on line 22 of FIG. I.
  • FIG. 3 is a section on line 3--3 of FIG. 2.
  • an optical smoke detector comprises a housing with bottom and top walls I and 2 and a circular side wall 3. Porous foam pads 4 in ports through the side wall admit air and air borne particles like smoke while excluding light from a dark chamber 6 which on one side is closed by an optical block 7 similarly as is described in U.S. Pat. No. 3,723,747.
  • the optical block mounts an exciter lamp 8 such as Hudson or GE No. 1 type 755 whose filament 9 is a straight coil.
  • a lamp lens 11 beams a cone of light from the lamp on a path through a passage 12 in the block along an axis Al across the dark chamber 6.
  • a detector cell 13 views the chamber through a second passage I4, a cell lens 16 along an axis A2 120 from the lamp axis Al. Also mounted in the optical block 7 is a compensating photocell 14 described in said US. Pat. No. 3,723,747 which receives light directly from the lamp 9 balances certain aging effects in the smoke cell 13.
  • smoke for example, enters the dark chamber 6 through the foam ports 4, smoke in the detection or intersection zone Z of the light path on axis A1 and the cell viewing path on axis A2 scatters light to the smoke cell 13 causing it to respond with a photoelectric signal.
  • the smoke cell is connected through terminals 16 to an alarm circuit board 18, the compensating cell 14 being connected to the board through terminals 17.
  • the lamp, cells and circuit are designed to respond to a predetermined smoke obscuration percentage as previously defined in BACKGROUND OF THE INVENTION, the preferred percentage being close to 2 percent, and up to 10 percent being allowable but increasingly less desirable.
  • the desired or predetermined level of detector response to the amount of light scattered from smoke of such obscuration density may be calibrated as light intensity or the corresponding smoke obscuration percentage.
  • the detector as a whole is tested under the same conditions as with the presence of the predetermined level of smoke in the chamber 6, by scattering a calibrated amount of light from the light path A1 at the intersection zone Z back along the cell viewing path A2 with a particle simulator 20.
  • the simulator comprises a wire bell crank having a finger grip 21 outside the circular chamber wall 3, an axial shaft portion 22 with a central U-bend 23 and a relatively fine wire 24 spot welded to its inner end in the dark chamber 6.
  • the shaft 2 is pivotally held in snap-in sockets formed in bosses 26 molded in and depending from the plastic top wall 2.
  • the U-bend portion 23 is angularly offset approximately 25 from the fine wire and limits rotation of the bell crank by engagement with a set screw 25 threaded through the top wall 2.
  • the fine wire 24 hangs vertically out of the light path on axis A1 and the smoke detection zone Z, as shown in FIGS. 2 and 3.
  • the fine wire 24 is of a diameter and surface area in proportion to the cross section of the conic light beam on axis A1 at the zone Z such that it effectively scatters a calibrated amount of light corresponding to that scattered by smoke of 2 to 10 percent obscuration density when swung through the zone Z from the solid line position in FIG. 3 to the phantom position 24
  • the calibrated light intensity is equivalent to 5 to 10 percent smoke since detector components are not presently expected to maintain an initial sensitivity to 2 percent smoke for several years and yet are acceptable at approximately 5 to 10 percent smoke level sensitivities.
  • I type 755 lamp 8 a Clairex type 5M7 smoke cell 13, and light and cell passages of about onethird inch a fine wire diameter of 34 gauge or about th inch diameter scatters a calibrated intensity of light from the detection zone Z to the cell 13 corresponding to the range of 2 to percent smoke.
  • the whole particle simulator including the fine wire 24 has a dull black oxide finish with a light waxing.
  • the operability test is made by slowly swinging the particle simulator completely through the light path at the intersection zone Z until the U-bend hits the setscrew 25 after the fine wire has substantially passed through the zone.
  • the set screw can be adjusted to stop the fine wire at a central position in the zone, but because the location of the filament 9 in the lamp 8 varies, the location of the light axis A] and the center of the intersection zone Z will shift from lamp to lamp. However, with close tolerance of filament position or by lamp selection the fine wire may be stopped in the zone.
  • An opticle particle detector comprising: a housing enclosing a dark chamber; a lamp mounted on the housing and means to direct light on a confined path into the chamber; a photosensitive device on the housing viewing the light path and responsive to light scattered by particles in the light path; and
  • a particle simulating member having a light scattering surface of predetermined width and of extent at least substantially as great as the cross section of the light beam, the member being mounted on the housing for continuous, unobstructed movement through positions in the light beam to and through a position of predetermined light scatter without selection of the position by the operator, so that during such movement a calibrated intensity of light will be scattered to the device.
  • particle detector according to claim 1 wherein the photoelectric device is responsive to a calibrated intensity of light scattered from the path to the device by a predetermined particle density to produce an alarm signal, and said particle simulating member being of a size to scatter light of the calibrated intensity.
  • a particle detector according to claim 1 wherein the simulator comprises a rotatable bell crank with a finger grip at one end and a light scattering flag at its other end.
  • the bell crank has an intermediate arm, and an adjustable stop limits movement of the intermediate arm.
  • a detector according to claim 1 wherein the light scattering surface is cylindrical.

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  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Emergency Management (AREA)
  • Business, Economics & Management (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Fire-Detection Mechanisms (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
US382521A 1972-12-27 1973-07-25 Optical smoke detector with light scattering test device Expired - Lifetime US3868184A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US382521A US3868184A (en) 1973-07-25 1973-07-25 Optical smoke detector with light scattering test device
GB5050773A GB1434658A (en) 1972-12-27 1973-08-03 Optical particle detectors with light scattering test device
CA184,698A CA1014637A (en) 1973-07-25 1973-10-31 Optical particle detector with light scattering test device
DE2355784A DE2355784C2 (de) 1973-07-25 1973-11-08 Rauchmelder nach dem Streulichtprinzip
JP12714673A JPS5711013B2 (fr) 1973-07-25 1973-11-12
FR7341044A FR2239168A5 (fr) 1973-07-25 1973-11-19
IT9693/73A IT1000974B (it) 1973-07-25 1973-11-23 Rivelatore ottico di fumo con di spositivo di prova della dispersio ne di luce

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US382521A US3868184A (en) 1973-07-25 1973-07-25 Optical smoke detector with light scattering test device

Publications (1)

Publication Number Publication Date
US3868184A true US3868184A (en) 1975-02-25

Family

ID=23509319

Family Applications (1)

Application Number Title Priority Date Filing Date
US382521A Expired - Lifetime US3868184A (en) 1972-12-27 1973-07-25 Optical smoke detector with light scattering test device

Country Status (6)

Country Link
US (1) US3868184A (fr)
JP (1) JPS5711013B2 (fr)
CA (1) CA1014637A (fr)
DE (1) DE2355784C2 (fr)
FR (1) FR2239168A5 (fr)
IT (1) IT1000974B (fr)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3985453A (en) * 1974-07-19 1976-10-12 Matsushita Electric Works, Ltd. Light scattering type smoke detector
US3992102A (en) * 1974-04-17 1976-11-16 Hochiki Corporation Photoelectric smoke detector with means for adjusting the amount of light projected into the detection region
US4021792A (en) * 1975-06-23 1977-05-03 Wellen Industries Smoke alarm
US4053785A (en) * 1976-01-07 1977-10-11 General Signal Corporation Optical smoke detector with smoke effect simulating means
JPS52141682A (en) * 1976-05-20 1977-11-26 Matsushita Electric Works Ltd Sensitivity tester of photoelectric sensor
JPS533881A (en) * 1976-07-01 1978-01-13 Matsushita Electric Works Ltd Sensitivity checking method for scattered light type smoke detector
US4099178A (en) * 1977-04-07 1978-07-04 Emdeko International, Inc. Test means for light responsive smoke detector
US4144458A (en) * 1977-11-29 1979-03-13 Chloride Incorporated Smoke detector with test means for simulating a predetermined concentration of smoke
US4144459A (en) * 1977-11-29 1979-03-13 Chloride Incorporated Smoke detector with test means for simulating a predetermined percentage of smoke
US4166698A (en) * 1977-06-10 1979-09-04 American District Telegraph Company Secondary light testing in optical smoke detectors
US4216377A (en) * 1977-06-27 1980-08-05 Nittan Company, Limited Light scattering smoke detector
US4249082A (en) * 1977-09-20 1981-02-03 Cybernet Electronics Corporation Photoelectric smoke sensor box
US4360270A (en) * 1981-02-17 1982-11-23 Jeck Richard K Calibration and testing device for optical, single particle, size spectrometers
US5523743A (en) * 1995-04-13 1996-06-04 Digital Security Controls Ltd. Self-diagnostic smoke detector
US20030209670A1 (en) * 2002-05-13 2003-11-13 Precision Instrument Development Center, National Science Council Sensitivity adjusting equipment of photoelectric smoke detector
US20100271220A1 (en) * 2009-04-24 2010-10-28 Pattok Greg R Detection Device System and Device Thereof
US8836532B2 (en) 2009-07-16 2014-09-16 Gentex Corporation Notification appliance and method thereof
USD770929S1 (en) * 2014-06-26 2016-11-08 Life Safety Distribution Ag Optical block
CN106407514A (zh) * 2016-08-31 2017-02-15 合肥科斯孚安全科技有限公司 一种双光路火灾烟雾探测烟室优化设计方法

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5427672U (fr) * 1977-07-25 1979-02-23
CH621640A5 (fr) * 1977-11-21 1981-02-13 Cerberus Ag
SU873041A1 (ru) * 1978-01-24 1981-10-15 Предприятие П/Я А-7555 Фотоэлектрический преобразователь
CH656474A5 (de) * 1981-11-11 1986-06-30 Cerberus Ag Rauchdetektor.
JPS58170550U (ja) * 1982-05-10 1983-11-14 ホーチキ株式会社 光電式煙感知器
DE102009054141A1 (de) 2009-11-13 2011-05-19 Job Lizenz Gmbh & Co Kg Verfahren zum Prüfen der Funktion eines Rauchmelders

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920525A (en) * 1956-08-13 1960-01-12 Arthur V Appel Apparatus for automatically counting and sizing airborne particles
US3065665A (en) * 1958-10-30 1962-11-27 Courtaulds Ltd Nephelometers
US3234846A (en) * 1959-11-18 1966-02-15 Standard Oil Co Continuously recording turbidity meter
US3505529A (en) * 1968-02-08 1970-04-07 Bliss Co Radiation sensitive smoke detecting device
US3702734A (en) * 1971-05-03 1972-11-14 Saab Scania Ab Calibration means for instrument for reading dust accumulations on dark slides

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1115477B (de) * 1959-08-12 1961-10-19 Lentia Gmbh Ortsfestes, industrielles Aerosolmessgeraet
US3396387A (en) * 1962-07-24 1968-08-06 Kidde & Co Walter Supervised apparatus for detecting suspended matter in fluids
US3483385A (en) * 1966-05-09 1969-12-09 Bendix Corp Apparatus for comparing the surface reflectivity of materials

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920525A (en) * 1956-08-13 1960-01-12 Arthur V Appel Apparatus for automatically counting and sizing airborne particles
US3065665A (en) * 1958-10-30 1962-11-27 Courtaulds Ltd Nephelometers
US3234846A (en) * 1959-11-18 1966-02-15 Standard Oil Co Continuously recording turbidity meter
US3505529A (en) * 1968-02-08 1970-04-07 Bliss Co Radiation sensitive smoke detecting device
US3702734A (en) * 1971-05-03 1972-11-14 Saab Scania Ab Calibration means for instrument for reading dust accumulations on dark slides

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3992102A (en) * 1974-04-17 1976-11-16 Hochiki Corporation Photoelectric smoke detector with means for adjusting the amount of light projected into the detection region
US3985453A (en) * 1974-07-19 1976-10-12 Matsushita Electric Works, Ltd. Light scattering type smoke detector
US4021792A (en) * 1975-06-23 1977-05-03 Wellen Industries Smoke alarm
US4053785A (en) * 1976-01-07 1977-10-11 General Signal Corporation Optical smoke detector with smoke effect simulating means
JPS52141682A (en) * 1976-05-20 1977-11-26 Matsushita Electric Works Ltd Sensitivity tester of photoelectric sensor
JPS533881A (en) * 1976-07-01 1978-01-13 Matsushita Electric Works Ltd Sensitivity checking method for scattered light type smoke detector
US4099178A (en) * 1977-04-07 1978-07-04 Emdeko International, Inc. Test means for light responsive smoke detector
US4166698A (en) * 1977-06-10 1979-09-04 American District Telegraph Company Secondary light testing in optical smoke detectors
US4216377A (en) * 1977-06-27 1980-08-05 Nittan Company, Limited Light scattering smoke detector
US4249082A (en) * 1977-09-20 1981-02-03 Cybernet Electronics Corporation Photoelectric smoke sensor box
US4144459A (en) * 1977-11-29 1979-03-13 Chloride Incorporated Smoke detector with test means for simulating a predetermined percentage of smoke
US4144458A (en) * 1977-11-29 1979-03-13 Chloride Incorporated Smoke detector with test means for simulating a predetermined concentration of smoke
US4360270A (en) * 1981-02-17 1982-11-23 Jeck Richard K Calibration and testing device for optical, single particle, size spectrometers
US5523743A (en) * 1995-04-13 1996-06-04 Digital Security Controls Ltd. Self-diagnostic smoke detector
US20030209670A1 (en) * 2002-05-13 2003-11-13 Precision Instrument Development Center, National Science Council Sensitivity adjusting equipment of photoelectric smoke detector
US20100271220A1 (en) * 2009-04-24 2010-10-28 Pattok Greg R Detection Device System and Device Thereof
US8232884B2 (en) 2009-04-24 2012-07-31 Gentex Corporation Carbon monoxide and smoke detectors having distinct alarm indications and a test button that indicates improper operation
US8836532B2 (en) 2009-07-16 2014-09-16 Gentex Corporation Notification appliance and method thereof
USD770929S1 (en) * 2014-06-26 2016-11-08 Life Safety Distribution Ag Optical block
CN106407514A (zh) * 2016-08-31 2017-02-15 合肥科斯孚安全科技有限公司 一种双光路火灾烟雾探测烟室优化设计方法
CN106407514B (zh) * 2016-08-31 2020-06-05 合肥科斯孚安全科技有限公司 一种双光路火灾烟雾探测烟室优化设计方法

Also Published As

Publication number Publication date
CA1014637A (en) 1977-07-26
IT1000974B (it) 1976-04-10
JPS5034874A (fr) 1975-04-03
JPS5711013B2 (fr) 1982-03-02
DE2355784C2 (de) 1983-10-27
DE2355784A1 (de) 1975-02-06
FR2239168A5 (fr) 1975-02-21

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Date Code Title Description
AS Assignment

Owner name: SENTROL ACQUISITION CORP. A DE CORPORATION, OREGO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ELECTRO SIGNAL LAB, INC., A CORPORATION OF DE;REEL/FRAME:005913/0715

Effective date: 19910531

AS Assignment

Owner name: SENTROL, INC. A CORP. OF OREGON, OREGON

Free format text: MERGER;ASSIGNOR:SENTROL ACQUISITION CORP. A CORP. OF DELAWARE (MERGED INTO);REEL/FRAME:006071/0296

Effective date: 19920103