US3562534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoelectric level control system with lamp operated at alternate brightness utilizing separate photocell and scr
Assignee: Robertshaw US Holding Corp
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Filing: 1969-05-19
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Granted: 1971-02-09
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Expires: 1989-05-19
Abstract
Abstract An electric lamp projects a light beam on a level at which a body of material is to be maintained and onto a light sensitive resistance element. When the beam is unobstructed the element triggers an SCR which conducts and initiates depositing of material until the material obstructs the beam whereby the element deactivates the SCR to terminate depositing of material. The lamp is energized by a center tap transformer winding connected to the lamp filament so that the lamp is energized by a full wave AC rectified to DC when the SCR conducts and by onehalf wave AC rectified when the SCR is nonconducting whereby the lamp intensity is high during depositing of material and low during the period the light is obstructed by material.
Inventors
- 👤 Jay H Jarrett
- 👤 Jerome L Lorenz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:35
CPC Classifications
F; F25; F25C; F25C5/00; F25C5/18; F25C5/182; F25C5/187; G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/284; G01F23/292; G05; G05D; G05D9/00; G05D9/12
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
234 words
A material level sensing apparatus comprising: an electric load means; means to energize said load means comprising, a transformer having a center taped secondary winding, conductor means connecting one end of said winding with one terminal of said load means, conductor means connecting the other end of said winding with the other terminal of said load means: an SCR in one of said conductor means for controlling the flow of current therethrough; a light sensitive resistor having one terMinal connected with the center tap of said winding; a circuit connecting the other terminal of said light sensitive resistor with one end of said winding, the last mentioned circuit including a resistance element, means connecting the gate of said SCR in said circuit between said resistance element and said light sensitive resistor; and electric lamp means adapted to project a beam of light across a space in which material is adapted to accumulate, one terminal of said lamp means connected with said center tap and the other terminal of said lamp means connected to the second mentioned means between said load means and said SCR; a shunt circuit between said SCR and the first mentioned conductor means and including a diode arranged to block the flow of current from the last mentioned conductor means to said SCR; and a diode in said center tap circuit for said light sensitive resistor and for said lamp means.
Claim 2
Dependent Claim
234 words
A material level sensing apparatus comprising: an electric load means; means to energize said load means comprising, a transformer having a center taped secondary winding, conductor means connecting one end of said winding with one terminal of said load means, conductor means connecting the other end of said winding with the other terminal of said load means: an SCR in one of said conductor means for controlling the flow of current therethrough; a light sensitive resistor having one terMinal connected with the center tap of said winding; a circuit connecting the other terminal of said light sensitive resistor with one end of said winding, the last mentioned circuit including a resistance element, means connecting the gate of said SCR in said circuit between said resistance element and said light sensitive resistor; and electric lamp means adapted to project a beam of light across a space in which material is adapted to accumulate, one terminal of said lamp means connected with said center tap and the other terminal of said lamp means connected to the second mentioned means between said load means and said SCR; a shunt circuit between said SCR and the first mentioned conductor means and including a diode arranged to block the flow of current from the last mentioned conductor means to said SCR; and a diode in said center tap circuit for said light sensitive resistor and for said lamp means.
Claim 3
Dependent Claim
24 words
A material level sensing apparatus as defined in claim 1 further characterized by a rheostat being included in an energizing circuit for said lamp.
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) | 1974-02-08 | 1974-08-10 | 1975-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-08 | 1978-08-10 | 1979-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-08 | 1982-08-10 | 1983-02-09 | $7700.00 | Window Closed / Lapsed |