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Title: US5581241: Ultra-sensitive smoke detector
[ Derwent Title ]

Country: US United States of America

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10 pages

Inventor: Kaufman, Michael; Cleveland Heights, OH
Thomas, Richard W.; Bedford, OH

Assignee: Voice Products Inc., Cleveland, OH
other patents from VOICE PRODUCTS INC. (726179) (approx. 1)
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Published / Filed: 1996-12-03 / 1994-08-12

Application Number: US1994000289659

IPC Code: Advanced: G08B 17/107;
Core: G08B 17/103;
IPC-7: G08B 17/10;

ECLA Code: G08B17/107;

U.S. Class: Current: 340/630; 250/573; 250/574; 340/628; 340/629; 356/339;
Original: 340/630; 340/628; 340/629; 356/339; 250/573; 250/574;

Field of Search: 250/573,574,575 356/338,339 340/628,629,630

Priority Number:
1994-08-12  US1994000289659

Abstract: A smoke detector that operates on the principle of scattered light is disclosed that has the capability of an operating sensitivity that is tens of times greater than that of smoke detectors presently available. Plural light sources are used, their light rays directed radially toward the center of a cylindrical detector chamber having a mirrored wall that reflects light back toward the chamber's center, thereby to brightly illuminate a central detection zone. Scattered light from smoke in this zone is detectable by a photocell at right angles to the converging multiple light rays. To obtain highly improved stability of the light output that enables ultra-high sensitivity, the light sources are light-emitting diodes in series connection and they are driven by a very stable constant voltage source that also powers the photocell detector. This system gains impressive sensitivity while reducing nuisance alarms that have been a common problem regarding efforts to increase smoke detector sensitivity. Whereas the goal of this invention is to improve the public safety, improvements are presented in smoke collection also, whereby ambient air is quickly and efficiently brought to the detector cell itself using convection currents that are enhanced by the aerodynamic design of the housing surrounding the cell.

Attorney, Agent or Firm: Bergquist, Donald A. ;

Primary / Asst. Examiners: Hofsass, Jeffery; Mannava, Ashok

Maintenance Status: E1 Expired  Check current status

INPADOC Legal Status: Show legal status actions

Family: None

First Claim:
Show all 9 claims
We claim:     1. A smoke detector of the light-scattering type having a detection chamber comprising:
  • a. a cylindrical wall having a continuous mirrored internal surface that reflects nearly 100% of light impinging thereupon, said cylindrical wall having an axis;
  • b. a photocell having a field of detection extending along said axis within said detection chamber; and
  • c. means to introduce a beam of light through said wall in a plane perpendicular to said axis,
wherein said beam is repeatedly reflected by different parts of said continuous mirrored wall, forming a plethora of light beams, both direct and reflected, that intersect and cross in a myriad of angles, while remaining substantially in said plane, thereby to brightly illuminate the central region of said chamber to provide light that is scattered by smoke present in said detection chamber, some of said light is scattered at an angle of substantially 90° from said light beams and is thus detected by said photocell which provides an output signal.

Background / Summary: Show background / summary

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Description: Show description

Forward References: Show 6 U.S. patent(s) that reference this one

U.S. References: Go to Result Set: All U.S. references   |  Forward references (6)   |   Backward references (15)   |   Citation Link

Patent  Pub.Date  Inventor Assignee   Title
Get PDF - 5pp US3799670  1974-03 Kohr  Pyrotector Europe GmbH SMOKE DETECTOR
Get PDF - 4pp US3914616  1975-10 Mooibroek   Smoke detector
Get PDF - 4pp US4025915  1977-05 Enemark  Electro Signal Lab, Inc. LED smoke detector circuit
Get PDF - 7pp US4121110  1978-10 Solomon   Optically biased smoke detector
Get PDF - 9pp US4181439  1980-01 Tresch et al.  Cerberus AG Smoke detector with a conical ring-shaped radiation region
Get PDF - 5pp US4221485  1980-09 Schulze  Honeywell Inc. Optical smoke detector
Get PDF - 5pp US4469953  1984-09 Fujisawa et al.  Nittan Company, Limited Combination ionization and photoelectric smoke detector
Get PDF - 7pp US4678921  1987-07 Nakamura et al.  Nippondenso Co., Ltd. Photo-electric smoke detector with light shielding electrode
Get PDF - 8pp US4754150  1988-06 Orioka et al.  Nohmi Bosai Kogyo Co. Ltd. Photoelectric smoke detector
Get PDF - 5pp US4758733  1988-07 Mochizuki  Nohmi Bosai Kogyo Co., Ltd. A labyrinthine light scattering-type smoke detector
Get PDF - 6pp US4769550  1988-09 Dolnick  Quantum Group, Inc. Dual scattering-type smoke detector with cross-checking
Get PDF - 7pp US4857895  1989-08 Kaprelian   Combined scatter and light obscuration smoke detector
Get PDF - 8pp US4906978  1990-03 Best et al.  Cerberus AG Optical smoke detector
Get PDF - 11pp US5008559  1991-04 Beyersdorf   Method for operating an optical smoke detector and optical smoke detector for the method
Get PDF - 13pp US5381130  1995-01 Thuillard et al.  Cerberus AG Optical smoke detector with active self-monitoring
Foreign References:
Publication Date IPC Code Assignee   Title
  JP04042054 1992-07       

Other Abstract Info: DERABS G97-033699 DERG97-033699

Other References:
  • Jonathan Dahl, Disney Could Jump on This Idea By Offering a Jimminy Cricket Line, The Wall Street Journal, Thursday, Aug. 12, 1993.

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