Patent US3822186A successfully refreshed from Google Patents.
Patent US4543891A successfully refreshed from Google Patents.
US4543891A
Expired / Lapsed
US
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Apparatus and process for heat treatment
Assignee: Westinghouse Electric Corp
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Filing: 1984-04-12
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Granted: 1985-10-01
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Expires: 2004-04-12
Abstract
Abstract Apparatus and process is disclosed for heat treating of material in a furnace comprising a fan driven by an electric motor, a load sensor which senses the motor load and a speed controller responsive to the load sensor signal for controlling the speed of the electric motor.
Inventors
- 👤 William T. O'Sullivan
- 👤 Earl C. Pace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:07
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/52; C21D9/54; C21D9/663; C21D9/673; C21D11/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
121 words
Apparatus for batch-annealing a charge comprising: (a) a batch-annealing furnace; (b) a fan for circulating hot gas within said furnace; (c) an electric motor on which a load is exerted by said fan; (d) a load transducer for detecting an electrical load on said motor and capable of generating a load signal; (e) a load change detector responsive to said load signal and capable of generating a load change signal; (f) a frequency reference integrator responsive to said load change signal and capable of generating, storing and changing a reference signal responsive to said load change signal; and (g) an adjustable frequency drive responsive to said reference signal and capable of supplying a varying frequency alternating current power to said motor.
Claim 2
Dependent Claim
121 words
Apparatus for batch-annealing a charge comprising: (a) a batch-annealing furnace; (b) a fan for circulating hot gas within said furnace; (c) an electric motor on which a load is exerted by said fan; (d) a load transducer for detecting an electrical load on said motor and capable of generating a load signal; (e) a load change detector responsive to said load signal and capable of generating a load change signal; (f) a frequency reference integrator responsive to said load change signal and capable of generating, storing and changing a reference signal responsive to said load change signal; and (g) an adjustable frequency drive responsive to said reference signal and capable of supplying a varying frequency alternating current power to said motor.
Claim 3
Dependent Claim
143 words
A process of batch-annealing a charge comprising the steps of: (a) increasing the temperature of a heat transfer gas within a batch-annealing furnace during heat-up of said charge; (b) circulating said heat transfer gas within said batch-annealing furnace with a fan driven by an electric motor; (c) sensing a change in the electrical load on said motor in response to a change in density of said heat transfer gas and generating a signal related thereto; (d) increasing the speed of said motor responsive to said signal to increase gas circulation within said furnace as the density of said gas decreases; (e) decreasing the temperature of said heat transfer gas within said furnace during cool-down of said charge; and (f) decreasing the speed of said motor responsive to said signal to decrease gas circulation within said furnace as the density of said gas increases.
Claim 4
Dependent Claim
143 words
A process of batch-annealing a charge comprising the steps of: (a) increasing the temperature of a heat transfer gas within a batch-annealing furnace during heat-up of said charge; (b) circulating said heat transfer gas within said batch-annealing furnace with a fan driven by an electric motor; (c) sensing a change in the electrical load on said motor in response to a change in density of said heat transfer gas and generating a signal related thereto; (d) increasing the speed of said motor responsive to said signal to increase gas circulation within said furnace as the density of said gas decreases; (e) decreasing the temperature of said heat transfer gas within said furnace during cool-down of said charge; and (f) decreasing the speed of said motor responsive to said signal to decrease gas circulation within said furnace as the density of said gas increases.
Claim 5
Independent Claim
113 words
A method for significantly reducing the processing time in a batch-annealing furnace comprising the steps of: (a) circulating a heat transfer gas within said furnace with a fan driven by an electric motor; (b) sensing the electrical load on said motor and generating a signal related to said load; (c) increasing the speed of said motor in response to a change in said signal to maintain a substantially constant load thereon as said gas is heated and the density thereof decreases; and (d) decreasing the speed of said motor in response to a change in said signal to maintain said load substantially constant as said gas is cooled and the density thereof increases.
Claim 6
Independent Claim
113 words
A method for significantly reducing the processing time in a batch-annealing furnace comprising the steps of: (a) circulating a heat transfer gas within said furnace with a fan driven by an electric motor; (b) sensing the electrical load on said motor and generating a signal related to said load; (c) increasing the speed of said motor in response to a change in said signal to maintain a substantially constant load thereon as said gas is heated and the density thereof decreases; and (d) decreasing the speed of said motor in response to a change in said signal to maintain said load substantially constant as said gas is cooled and the density thereof increases.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-30 | 1989-04-01 | 1989-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-30 | 1993-04-01 | 1993-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-30 | 1997-04-01 | 1997-10-01 | $7700.00 | Window Closed / Lapsed |