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 Title: |
US5581241:
Ultra-sensitive smoke detector
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Kaufman, Michael; Cleveland Heights, OH
Thomas, Richard W.; Bedford, OH
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| 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
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| Application Number: |
US1994000289659
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| IPC Code: |
Advanced:
G08B 17/107;
Core:
G08B 17/103;
IPC-7:
G08B 17/10;
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| ECLA Code: |
G08B17/107;
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| 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;
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| Field of Search: |
250/573,574,575
356/338,339
340/628,629,630
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| Priority Number: |
| 1994-08-12 |
US1994000289659 |
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| 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.
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| Attorney, Agent or Firm: |
Bergquist, Donald A. ;
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| Primary / Asst. Examiners: |
Hofsass, Jeffery; Mannava, Ashok
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| Maintenance Status: |
E1 Expired Check current status
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| INPADOC Legal Status: |
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| Family: |
None
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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.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 6 U.S. patent(s) that reference this one
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