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US4297578A Expired / Lapsed US ⏱️ 0.0 years remaining

Airborne dust monitor

Assignee: Individual
•
Filing: 1980-01-09
•
Granted: 1981-10-27
•
Expires: 2000-01-09
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Abstract

Abstract An airborne dust monitor. Photosensitive elements detect a predetermined airborne dust level at a test region adjacent the photosensitive elements. The photosensitive elements are housed within a flue which shields the test region from ambient light while it conducts ambient air through the test region. In a preferred embodiment, the flue is formed of generally vertical sidewall members which define an ambient air passage through the test region, air passage outlets positioned above the test region and a baffle generally at the inlet of the air passage for allowing the entry of ambient air to the passage while blocking light from the test region. A test system may be provided by which a member is selectively positionable within the test region. Preferably, the photosensitive detecting elements include a radiant energy source and an element responsive to that radiant energy, most preferably infrared energy, the photosensitive elements being positioned to minimize dust settlement on the acting portions thereof.

Inventors

  • 👤 William R. Carter

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 07:51
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/49; G01N21/53

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 80 words
In an airborne dust monitor of the type having photosensitive means for detecting a predetermined airborne dust level at a test region, the improvement which comprises generally vertical flue means for establishing a flow of ambient air through said test region, said detecting means being housed within said flue means adjacent said test region, and test means, including test element means, operable from the outside of said flue means for selectively positioning said test element means within said test region.
Claim 2
Dependent Claim 80 words
In an airborne dust monitor of the type having photosensitive means for detecting a predetermined airborne dust level at a test region, the improvement which comprises generally vertical flue means for establishing a flow of ambient air through said test region, said detecting means being housed within said flue means adjacent said test region, and test means, including test element means, operable from the outside of said flue means for selectively positioning said test element means within said test region.
Claim 3
Dependent Claim 63 words
The airborne dust monitor of claim 1 wherein said flue means comprises generally vertical sidewall means defining an ambient air passage through said test region, air passage outlet means positioned above said test region and baffle means generally at the inlet of said air passage for allowing the entry of ambient air to said passage while blocking ambient light from said test region.
Claim 4
Dependent Claim 24 words
The airborne dust monitor of claim 2 wherein said photosensitive detecting means comprises radiant energy source means and means responsive to said radiant energy.
Claim 5
Dependent Claim 26 words
The airborne dust monitor of claim 3 wherein said radiant energy source and responsive means are positioned to minimize dust settlement on the acting portions thereof.
Claim 6
Dependent Claim 18 words
The airborne dust monitor of claim 4 wherein said radiant energy source and responsive means comprise infrared means.
Claim 7
Dependent Claim 23 words
The airborne dust monitor of claim 1 wherein said photosensitive detecting means is positioned to minimize dust settlement on the acting portions thereof.
Claim 8
Dependent Claim 63 words
The airborne dust monitor of claim 6 wherein said flue means comprises generally vertical sidewall means defining an ambient air passage through said test region, air passage outlet means positioned above said test region and baffle means generally at the inlet of said air passage for allowing the entry of ambient air to said passage while blocking ambient light from said test region.

References Cited (Backward Citations)

US2406409A Cited
US3317730A Cited
US3854045A Cited
US3809913A Cited
JPS551574A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1984-10-26 1985-04-27 1985-10-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1988-10-26 1989-04-27 1989-10-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1992-10-26 1993-04-27 1993-10-27 $7700.00 Window Closed / Lapsed

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