US3579216A - Particle detector - Google Patents

Particle detector Download PDF

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Publication number
US3579216A
US3579216A US845646A US3579216DA US3579216A US 3579216 A US3579216 A US 3579216A US 845646 A US845646 A US 845646A US 3579216D A US3579216D A US 3579216DA US 3579216 A US3579216 A US 3579216A
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United States
Prior art keywords
detector
circuit
alarm
light
smoke
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Expired - Lifetime
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US845646A
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English (en)
Inventor
Alfred W Vasel
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Pyrotector Inc
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Individual
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Assigned to PYROTECTOR, INC.; A CORP OF RI. reassignment PYROTECTOR, INC.; A CORP OF RI. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: CHLORIDE INCORPORATED
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    • 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

Definitions

  • a light for illuminating smoke particles also illuminates a photocell providing a circuit path to maintain an alarm actuating device in a deenergized condition, and means is provided responsive to the detection of smoke to illuminate a second photocell to cause energization of the alarm.
  • This invention relates generally to a device for detecting particles in a fluid-suspending medium and to a circuit-controlling system adapted for use therewith, and has particular reference to a smoke detector of the diffusion type.
  • Particle detectors of this type utilize a dark chamber with means projecting a light beam across the chamber, and a photocell viewing the medial portion of the light beam and shielded from direct radiation from the light source.
  • a fluid medium carrying suspended particles enters the housing through suitable openings and passes through the light beam, the particles carried by the fluid medium cause radiation from the light source to be reflected or diffused onto the photocell. The resulting change in resistance of the cell is utilized to actuate an external alarm system.
  • the object of the invention is to provide a smoke detector of the diffusion type, which has control means energized by the energization of the light source to maintain a normally on" alarm switch in the of? position, and means responsive to the presence of smoke particles in the detector to deenergize said control means.
  • a further object of the invention is to provide a smoke detector of the diffusion type in which a direct current relays normally closed contacts are connected to an alarm-actuating circuit, said relay is energized to the open position by the energization of the light source, and means is provided responsive to the existence of smoke particles in the detector to deenergize the relay.
  • a further object of the invention is to provide a circuit'controlling system having switching means responsive to direct current to maintain a circuit in a first condition and responsive to alternating current to maintain the circuit in a second condition.
  • FIG. I is a top plan view of a particle detector labyrinth embodying the features of the invention, partly broken away to show the interior arrangement;
  • FIG. 2 is a view in section taken on line 2-2 of FIG. ll;
  • FIG. 3 is a schematic diagram of the electrical circuit of a particle detector embodying the features of the invention.
  • a particle detector 10 which comprises generally a housing 12, a light source 14 disposed outside the housing and a detector element 16 disposed in the housing in operative relation to appear hereinafter.
  • the detector 110 in the illustrated embodiment, is particularly adapted for use as the detector unit of a smoke alarm and for this purpose the housing 12 comprises a peripheral wall 18 having a pair of end caps 20 and 22 fomiing an internal dark chamber 2
  • the end caps extend beyond the periphery of the wall 18 and have inwardly turned flanges 26 and 28 which are spaced outwardly from the wall.
  • Each end of the wall is provided with a series of outwardly inclined spacing lugs 30, which are adapted to engage frictionally the inner surface of the flanges to retain the caps in assembly.
  • the flanges 26 and 28, in conjunction with the spacing lugs 30, form a peripheral passageway at each end of the wall to permit smoke to enter the chamber from the surrounding atmosphere.
  • a focusing tube 32 extends through the housing wall on one side thereof, and a light trap tube 34 is disposed in the housing wall on the opposite side in alignment with the focusing tube 32.
  • lens 36 of the converging type is disposed in the focusing tube 32, with a focal length such that light from the source 14 is focused in a converging beam onto the bottom of the light trap tube 34, so that the beam from the light has a minimum size at the bottom of said trap, and a minimum amount of the light from the source falls on any other portion of the interior surface of the housing.
  • a detector tube 38 extends through the housing wall between the light trap tube and the focusing tube, and is disposed generally perpendicular to the axes thereof.
  • the detector element 16 is disposed in the detector tube, and to restrict the field of view of the detector, a lens 40 of the converging type is disposed in the detector tube between the detector element and the chamber.
  • the lens 40 has a focal length such that the image of the detector element is focused onto a minimum area on the opposite surface of the housing wall and the cone of focus of the detector element is directed across the cone of focus of the light beam, so that the detector element views only the medial portion of the light beam and the field of view of the cell at the opposite wall portion is confined to the medial portion of the wall, so that the cell does not view the peripheral apertures at the top and bottom of the wall. Hence substantially no light reaches the detector element except light appearing in the focus cone of the lens 40.
  • the end 42 of the detector tube on the side adjacent the light tube extends forwardly to the cone of focus of the light beam to provide a shield against stray light from the inside surface of the focus tube.
  • the end of the detector tube from this foremost point is inclined rearwardly at an angle such that the inside surface of the detector tube cannot view the inside surface of the focus tube.
  • the side of the end of the detector tube adjacent the light trap tube is provided with an inclined shield 44!.
  • the detector element 16 may be any type of device which is responsive to a change in light intensity, such as a photoelectric or a photoresistive cell.
  • a photoelectric or a photoresistive cell One type of cell which has been found satisfactory is cadmium sulfide, which responds to an increase in light intensity by a decrease in resistance.
  • a detector circuit may be con nected to the detector element and adjusted to the cell resistance under normal conditions of no smoke so that a predetermined further decrease in cell resistance will actuate an external alarm connected to the detector circuit.
  • smoke enters the housing and appears in the light beam light from the smoke particles in the portion of the light beam viewed by the detector is reflected or diffused onto the detector cell, thereby lowering the resistance of the cell and actuating the alarm circuit.
  • FIG. 3 there is illustrated an alarm and control circuit for use with the labyrinth of FIGS. 1 and 2.
  • the circuit of FIG. 3, which may be energized from an alternating current source E is intended to actuate means for energizing an alarm A when the cell 16 views illuminated particles in the labyrinth, and also to actuate a control device D which may control the operation of a fire door or the like.
  • fire doors are ordinarily designed to be biased by weights or springs to the closed condition, and are held open by a retaining means which may include a control wire having a portion responsive to excessive heat to release the retaining wire and allow the door to close.
  • the retaining means may also include an electrically operated latch, which is normally energized, and which on deenergization releases the control wire to allow the door to close.
  • the device D represents an electrically operated latch which, when energized, retains a fire door or analogous device (not shown) in the open condition, and when deenergized, releases the door to-allow it to close automatically.
  • the alarm A may be energized by a separate source of power such as a battery B, whereas the door control device may be energized by the source E.
  • the alarm is connected to its power source B, through normally closed contacts X1 of a direct current relay R1 said contacts being held open when the relay coil is energized, and the door control device D is connected to the power source E through normally open contactsXZ of said relay, the contacts X2 being held closed when said relay is energized.
  • the coil of relayRl is energized from the AC source E through a series connected photocell PCZ and a diode rectifier D1.
  • a third photocell PC3 and a diode D2 which is reversed in polarity in relation to the diode D1 for a purpose to appear hereinafter.
  • the cellPCZ is physically positioned in relation to the light source bulb 14 so that when the bulb 14 is lit the cell PC2 receives radiation therefrom and its resistance is therefore maintained at a value low enough to permit sufficient half wave DC current to flow through the diode D5 and the coil of relay to hold contacts X1 open. Hence in case of bulb failure or power failure, the relay is deenergized, whereby the contacts X1 close to energize the alarm and contacts X2 open to deenergize the door control device D.
  • the photocell i6 is connected to the AC source E in series with a calibrating resistor Kl, with a neon bulb 50 being connected in parallel with the resistor Kl, and in series with the photocell 16.
  • the resistance of the cell 16 is so high that the voltage appearing across the resistor K1 and the neon bulb St) is not sufficient to ignite the bulb.
  • smoke particles diffuse into the housing 22 and enter the light beam, they are seen" by the cell 16 so that its resistance decreases.
  • its resistance has dropped to a predetermined value, the voltage across the neon bulb 59 and the resistor Kl becomes sufficient to ignite said neon bulb.
  • the cell PCS which is positioned to receive radiation from the bulb Stl is thereby illuminated and becomes conductive. Current can thereby flow through the diode D2 and the cell PC3, however only on the opposite halfcycle from that on which current flows through'the cell PCI and the diode Dll. Full wave AC voltage therefore appears across the coil of the relay R1 and the capacitor F.
  • the capacitor acts as a low-impedance shunt to the AC voltage, thereby reducing the current through the coil of relay Rl to a value such that the relay is deenergized and the contacts Xl close to energize the alarm.
  • the alarm is automatically shut off when the smoke conditions are eliminated, since the resulting rise in resistance of cell 16 extinguishes the neon bulb 50, raising the resistance of cell PC3, so that only DC power is now impressed across the relay coil and the capacitor F.
  • the relay coil is thereby energized again to open contacts X1 and close contacts X2, so that the door latch device is again energized.
  • the circuit providing the direct current to the relay coil is completed through a photocell, in some cases in place thereof a relay can be provided having a coil in series with the light 14, said relay having normally open contacts in the D1 circuit to the relay R1, which contacts are maintained closed when the light is enerized.
  • the relay R1, condenser F'and the two circuit paths thereto including the diodes D1 and D2 form a circuit-controlling system which provides a method by which direct current is provided to maintain a controlled circuit in a first condition and alternating current is provided to maintain the circuit in a second condition.
  • the specific embodiment illustrated also provides a system in which the illumination of one photocell maintains the circuit in the first condition, and the illumination of both photocells maintains the circuit in the second condition.
  • circuit is illustrated herein as being applied to a smoke detector, its use as shown in this application is exemplary only, since it is adapted for use in many other types of electrical devices.
  • a particle detector comprising a light source for illuminating particles to be detected, photoresistive detector means positioned to view said illuminated particles, alarm-actuating means including a switch operated by a relay havingan operating coil energizable by direct current to maintain said switch in an open circuit condition, a capacitor in parallel with said operating coil, and a pair of circuit paths to said operating coil and capacitor, a first circuit path having a diode poled in one direction and normally open circuit-completing means in series therewith, the other circuit path having a diode poled in the opposite direction and said photoresistive detector means in series therewith, said circuit-completing means being responsive to the energization of the light source for maintaining said circuit-completing means in a circuit-completing condition, whereby when alternating current is applied to the relay and said circuit paths, direct current is applied through said first circuit path to the operating coil of the relay to energize said coil, and when the photoresistive detector means views illuminated particles a circuit is completed through said other circuit path so

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Fire-Detection Mechanisms (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Warehouses Or Storage Devices (AREA)
US845646A 1966-03-10 1969-07-08 Particle detector Expired - Lifetime US3579216A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US53314066A 1966-03-10 1966-03-10
US84564669A 1969-07-08 1969-07-08

Publications (1)

Publication Number Publication Date
US3579216A true US3579216A (en) 1971-05-18

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Family Applications (1)

Application Number Title Priority Date Filing Date
US845646A Expired - Lifetime US3579216A (en) 1966-03-10 1969-07-08 Particle detector

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US (1) US3579216A (sv)
BE (1) BE693688A (sv)
CH (1) CH459611A (sv)
DE (1) DE1588617B1 (sv)
DK (1) DK116228B (sv)
FR (1) FR1511369A (sv)
GB (1) GB1160149A (sv)
IL (1) IL27293A (sv)
NL (1) NL6702484A (sv)
NO (1) NO120872B (sv)
SE (1) SE328807B (sv)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3710367A (en) * 1970-10-28 1973-01-09 Gen Motors Corp Lamp failure indicator for a dual-filament lamp
EP2128602A1 (en) * 2007-03-19 2009-12-02 Horkos Corporation Mist measuring apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115326790B (zh) * 2022-08-22 2024-04-12 东北大学秦皇岛分校 一种光电流和单光子检测装置及方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1877279A (en) * 1930-05-20 1932-09-13 Westinghouse Electric & Mfg Co Photosensitive device
US2032746A (en) * 1928-10-26 1936-03-03 Kidde & Co Walter Detection of suspended matter in fluids
US2033466A (en) * 1931-11-11 1936-03-10 Kidde & Co Walter Selective smoke detector
US2278920A (en) * 1939-03-15 1942-04-07 American District Telegraph Co Photoelectric smoke detection system
US2668284A (en) * 1950-02-28 1954-02-02 Specialties Dev Corp Apparatus for detecting suspended matter in fluids
US3202883A (en) * 1961-06-07 1965-08-24 Graviner Manufacturing Co Electrical circuits particularly for use with temperature detectors
US3207932A (en) * 1961-11-20 1965-09-21 Basic Electronic Controls Inc Switching device and circuit for radiation sensing apparatus
US3226703A (en) * 1962-11-19 1965-12-28 Sam M Finkle Fire detecting device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE928088C (de) * 1952-11-28 1955-05-23 Standard Elek Zitaets Ges Ag Ruhestromueberwachte Signalanlage nach dem Schleifensystem
BE564961A (sv) * 1957-02-19

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2032746A (en) * 1928-10-26 1936-03-03 Kidde & Co Walter Detection of suspended matter in fluids
US1877279A (en) * 1930-05-20 1932-09-13 Westinghouse Electric & Mfg Co Photosensitive device
US2033466A (en) * 1931-11-11 1936-03-10 Kidde & Co Walter Selective smoke detector
US2278920A (en) * 1939-03-15 1942-04-07 American District Telegraph Co Photoelectric smoke detection system
US2668284A (en) * 1950-02-28 1954-02-02 Specialties Dev Corp Apparatus for detecting suspended matter in fluids
US3202883A (en) * 1961-06-07 1965-08-24 Graviner Manufacturing Co Electrical circuits particularly for use with temperature detectors
US3207932A (en) * 1961-11-20 1965-09-21 Basic Electronic Controls Inc Switching device and circuit for radiation sensing apparatus
US3226703A (en) * 1962-11-19 1965-12-28 Sam M Finkle Fire detecting device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3710367A (en) * 1970-10-28 1973-01-09 Gen Motors Corp Lamp failure indicator for a dual-filament lamp
EP2128602A1 (en) * 2007-03-19 2009-12-02 Horkos Corporation Mist measuring apparatus
EP2128602A4 (en) * 2007-03-19 2011-12-21 Horkos Corp DEVICE FOR MEASURING FOG

Also Published As

Publication number Publication date
DE1588617B1 (de) 1972-05-31
DK116228B (da) 1969-12-22
CH459611A (de) 1968-07-15
NO120872B (sv) 1970-12-14
FR1511369A (fr) 1968-01-26
GB1160149A (en) 1969-07-30
BE693688A (sv) 1967-07-17
SE328807B (sv) 1970-09-21
NL6702484A (sv) 1967-09-11
IL27293A (en) 1971-03-24

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Legal Events

Date Code Title Description
AS Assignment

Owner name: PYROTECTOR, INC.; 333 LINCOLN ST., HINGHAM, MA. A

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:CHLORIDE INCORPORATED;REEL/FRAME:004094/0656

Effective date: 19830103