US3740148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Portable dust analyzer
Assignee: Pennsylvania Research Corp
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Filing: 1970-12-08
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Granted: 1973-06-19
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Expires: 1990-12-08
Abstract
Abstract A portable battery powered dust analyzer operating on the principle of light-scattering from individual airborne particles moving past a high intensity light, which is capable of counting and size discriminating air-borne particulate matter over several size ranges while providing immediate readout in which the flow passage system minimizes turbulence and recirculation allowing for small physical dimensions of the device and portability.
Inventors
- 👤 W Moroz
- 👤 G Anderson
- 👤 V Withstandley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:27
CPC Classifications
G; G01; G01N; G01N1/00; G01N1/02; G01N1/22; G01N1/2247; G01N15/00; G01N15/10; G01N15/14; G06; G06M; G06M1/00; G06M1/08; G06M1/10; G06M1/101; G01N1/2202; G01N2001/222; G01N2001/2223; G01N2015/1486; G01N2015/1493
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
198 words
A portable dust analyzing device including in combination a photometer head, a chamber within said head, a straight elongated needle for introducing sample air into said chamber for passage therethrough, a passage for introducing sheath air into said chamber, an elongated cylindrical channel having a smooth inner surface on the axis of which said needle is disposed for introducing sheath air into said chamber for passage therethrough formed as a portion of said passage between a bend therein and said chamber, the length to diameter ratio of said channel being at least seven to one, a light source, first lens means for producing from said light source a cleanly defined bright light field within said chamber through which air ejected by said Needle passes, a transducer, second lens means for receiving and directing light scattered in said chamber by particles in the sample air passing through the light field within said chamber to said transducer, said transducer receiving the converting light from said second lens means to electrical signals, electric circuit means for translating electrical signals from said transducer to read out form and independent power supply means operatively associated with said device for supplying electrical power thereto.
Claim 2
Dependent Claim
198 words
A portable dust analyzing device including in combination a photometer head, a chamber within said head, a straight elongated needle for introducing sample air into said chamber for passage therethrough, a passage for introducing sheath air into said chamber, an elongated cylindrical channel having a smooth inner surface on the axis of which said needle is disposed for introducing sheath air into said chamber for passage therethrough formed as a portion of said passage between a bend therein and said chamber, the length to diameter ratio of said channel being at least seven to one, a light source, first lens means for producing from said light source a cleanly defined bright light field within said chamber through which air ejected by said Needle passes, a transducer, second lens means for receiving and directing light scattered in said chamber by particles in the sample air passing through the light field within said chamber to said transducer, said transducer receiving the converting light from said second lens means to electrical signals, electric circuit means for translating electrical signals from said transducer to read out form and independent power supply means operatively associated with said device for supplying electrical power thereto.
Claim 3
Dependent Claim
60 words
A portable dust analyzing device in accordance with claim 1 in which shaped inlet and outlet nozzles are provided on said chamber having axes on the line of the axis of said channel, said inlet nozzle having the same throat diameter as said channel and having a divergent mouth with a radius of divergence one-half the diameter of its throat.
Claim 4
Dependent Claim
47 words
A portable dust analyzing device in accordance with claim 2 in which said outlet nozzle has a throat diameter less than the throat diameter of said inlet nozzle and a divergent mouth with a radius of divergence of said outlet nozzle one-half the diameter of its throat.
Claim 5
Dependent Claim
35 words
A portable dust analyzing device in accordance with claim 3 in which the velocity of the sheath air and the sample air is substantially equal and the Reynolds number for flow is less than 2,100.
Claim 6
Dependent Claim
56 words
A portable dust analyzing device in accordance with claim 4 in which an electrically driven pump is provided for drawing sheath air and sample air through said chamber for discharge from said device and means are provided to adjust the velocity of the sheath air to that substantially identical with the velocity of the sample air.
Claim 7
Dependent Claim
60 words
A portable dust analyzing device in accordance with claim 1 in which the transducer is a photomultiplier tube and current pulses are developed by said photomultiplier tube having amplitude and frequency respectively proportional to the size and quantity of particles passing through said photometer head, and circuit means providing an analog output directly proportional to the period of said pulses.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |