Patent US3906475A successfully refreshed from Google Patents.
US3906475A
Expired / Lapsed
US
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Powder level monitor
Assignee: Eastman Kodak Co
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Filing: 1974-05-16
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Granted: 1975-09-16
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Expires: 1994-05-16
Abstract
Abstract An apparatus for monitoring the level of finely powdered material within a hopper. A microphone disposed within the hopper monitors the environmental noise at a particular level within the hopper. Circuitry associated with the microphone is responsive to a marked change in the detected level of environmental noise for activating a powder level indicator when the level of powder in the hopper rises above or falls below the face of the microphone.
Inventors
- 👤 Jacob C Rubin
- 👤 John P Swapceinski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:36
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/296; G01F23/2966; G01F23/2967
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
118 words
Apparatus for monitoring the presence or absence of powder at a predetermined level within a hopper, said hopper being located in a noisy environment, said apparatus consisting of: a. a microphone disposed at a predetermined level withIn the hopper and responsive to environmental noise transmitted through the hopper to the interior thereof to produce a signal having a component proportional to the amplitude of the environmental noise at the predetermined level within the hopper; b. means for supporting said microphone at said predetermined level within the hopper; and c. means coupled to said microphone and responsive to a decrease in the amplitude of said signal for indicating the absence of powder at the predetermined level within the hopper.
Claim 2
Dependent Claim
118 words
Apparatus for monitoring the presence or absence of powder at a predetermined level within a hopper, said hopper being located in a noisy environment, said apparatus consisting of: a. a microphone disposed at a predetermined level withIn the hopper and responsive to environmental noise transmitted through the hopper to the interior thereof to produce a signal having a component proportional to the amplitude of the environmental noise at the predetermined level within the hopper; b. means for supporting said microphone at said predetermined level within the hopper; and c. means coupled to said microphone and responsive to a decrease in the amplitude of said signal for indicating the absence of powder at the predetermined level within the hopper.
Claim 3
Dependent Claim
27 words
The apparatus of claim 1 wherein said means for supporting said microphone is adjustable to support said microphone at a range of predetermined levels within the hopper.
Claim 4
Dependent Claim
122 words
The apparatus of claim 2 wherein the hopper includes a cover having a hole therein and said means for supporting said microphone comprises: a. a plastic rod having an end portion and a calibrated portion along the length thereof, said plastic rod being disposed generally vertically through the hole in the cover of the hopper so that at least a part of said calibrated portion extends above the cover of the hopper and said end portion extends into the hopper, said microphone being attached to said end portion of said plastic rod; and b. means for adjustably clamping said plastic rod at a desired extension into the hopper, whereby the level at which said microphone is disposed within the hopper is predetermined.
Claim 5
Dependent Claim
38 words
The apparatus of claim 1 wherein said microphone is a directional microphone having an active face, said active face being positioned at the predetermined level within the hopper at which the presence or absence of powder is monitored.
Claim 6
Dependent Claim
31 words
The apparatus of claim 1 wherein said signal also contains a range of frequency components and wherein said indicating means responds optimally to only a portion of said range of frequencies.
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) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |