US3553430A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system and apparatus for a heating station
Assignee: Polaroid Corp
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Filing: 1968-08-09
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Granted: 1971-01-05
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Expires: 1988-08-09
Abstract
Abstract A control system for regulating the power input to the heating station of a processing device. The system utilizes a gated, full-wave thyristor to regulate an AC power input to an electrical heating element. Using a thermistor as a temperature sensor, the control system functions to periodically sample heating station temperature at the commencement of each input power supply cycle. A signal threshold level is established within the sampling interval, below which full-power will be inserted through the thyristor.
Inventors
- 👤 Lawrence K M Ting
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:22
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/1906; G05D23/1909
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
188 words
A system for controlling the thermal output of an electrical heating element comprising: a source of oscillating electrical power coupled with said heating element; gated switching means operative to conduct an electrical current between said power source and said heating element upon receipt of a forward biasing gating signal and to continue to conduct until said current is discontinued; sensor means responsive to the temperature of said heating element for providing an electrical characteristic representative of said temperature; signal generator means operative to provide an enabling signal output within an interval of restricted duration substantially near the commencement of each cycle of said power source said output having an amplitude alterable about a predetermined threshold level in response to the variable electrical characteristic of said sensor means; and triggering means responsive to the output of said signal generator means, coupled with said switching means gate and operable to cause its activation upon receipt of a said enabling signal during said restricted interval at said threshold value, whereby a substantial proportion of power available from said source is applied to said heating element when said triggering means is activated.
Claim 2
Independent Claim
188 words
A system for controlling the thermal output of an electrical heating element comprising: a source of oscillating electrical power coupled with said heating element; gated switching means operative to conduct an electrical current between said power source and said heating element upon receipt of a forward biasing gating signal and to continue to conduct until said current is discontinued; sensor means responsive to the temperature of said heating element for providing an electrical characteristic representative of said temperature; signal generator means operative to provide an enabling signal output within an interval of restricted duration substantially near the commencement of each cycle of said power source said output having an amplitude alterable about a predetermined threshold level in response to the variable electrical characteristic of said sensor means; and triggering means responsive to the output of said signal generator means, coupled with said switching means gate and operable to cause its activation upon receipt of a said enabling signal during said restricted interval at said threshold value, whereby a substantial proportion of power available from said source is applied to said heating element when said triggering means is activated.
Claim 3
Dependent Claim
25 words
The control system of claim 1 wherein said signal generator means output threshold level is selected as the breakover signal level of said triggering means.
Claim 4
Dependent Claim
24 words
The control system of claim 1 wherein said sensor means comprises a nonlinear resistor means arranged in temperature sensing relationship with said heating element.
Claim 5
Dependent Claim
23 words
The control system of claim 3 wherein said sensor means is arranged in thermal bond with the heated environment of said heating element.
Claim 6
Dependent Claim
17 words
The control system of claim 3 in which said resistor means includes a negative temperature coefficient thermistor.
Claim 7
Dependent Claim
24 words
The control system of claim 1 in which said signal generator means is coupled in phase coincidence with said source of oscillating electrical power.
Claim 8
Dependent Claim
31 words
The control system of claim 1 wherein said signal generator means includes pulse forming means for restricting the duration of said interval at the commencement of each said power source cycle.
Claim 9
Dependent Claim
33 words
The control system of claim 1 in which: said power source provides alternating current power; and said switching means comprises gated full-wave control means connected between said power source and said heating element.
Claim 10
Dependent Claim
42 words
The control system of claim 20 in which: said triggering means is activated upon receipt of signals having values above a select breakover level; and said signal generator means threshold level is selected as the breakover signal level of said triggering means.
Claim 11
Dependent Claim
28 words
The control system of claim 9 in which said signal generator means includes signal clipping means for establishing the said amplitude threshold level of said enabling signal output.
Claim 12
Dependent Claim
24 words
The control system of claim 9 wherein said sensor means comprises a nonlinear resistor means arranged in temperature sensing relationship with said heating element.
Claim 13
Dependent Claim
37 words
The control system of claim 11 wherein said signal generator means includes pulse forming means for restricting the duration of said enabling signal output substantially within said interval at the commencement of each said power source cycle.
Claim 14
Dependent Claim
23 words
The control system of claim 11 wherein said sensor means is arranged in thermal bond with the heated element of said heating environment.
Claim 15
Dependent Claim
60 words
The control system of claim 11 in which: said signal generator means includes signal clipping means for establishing the said amplitude threshold level of said enabling signal output; and said signal generator means further includes pulse forming means for restricting the duration of said enabling signaling output substantially within said interval at the commencement of each said power source cycle.
Claim 16
Dependent Claim
26 words
The control system of claim 14 wherein said pulse forming means comprises an AC coupling circuit formed as a series connected capacitor means and resistor means.
Claim 17
Dependent Claim
29 words
The control system of claim 15 in which said coupling circuit resistor means is present as a variable resistor for adjusting the temperature operating level of said control system.
Claim 18
Dependent Claim
17 words
The control system of claim 16 in which said sensor means includes a negative temperature coefficient thermistor.
Claim 19
Dependent Claim
39 words
The control system of claim 17 including capacitor means coupled in parallel with said thermistor and responsive to the output of said enabling signal for buttressing current supply to said switching means upon each activation of said triggering means.
Claim 20
Independent Claim
186 words
A system for controlling the thermal output of an electrical heating element comprising: a source of alternating current electrical power coupled with said heating element; switching means including gated full-wave control means connected between said power source and said heating element for conducting an electrical current between said power source and said heating element upon receipt of a forward biasing gating signal and operative to continue to conduct until said current is discontinued; sensor means responsive to the temperature of said heating element for providing an electrical characteristic representative of said temperature; signal generator means operative to provide an enabling signal output within an interval near the commencement of each cycle of said power source said oUtput having an amplitude alterable about a predetermined threshold level in response to the variable electrical characteristic of said sensor means; means for coupling said signal generator means in phase coincidence with said power source; and triggering means responsive to the output of said signal generator means, coupled with said switching means gate and operable to cause its activation upon receipt of a said enabling signal at said threshold value.
Claim 21
Independent Claim
186 words
A system for controlling the thermal output of an electrical heating element comprising: a source of alternating current electrical power coupled with said heating element; switching means including gated full-wave control means connected between said power source and said heating element for conducting an electrical current between said power source and said heating element upon receipt of a forward biasing gating signal and operative to continue to conduct until said current is discontinued; sensor means responsive to the temperature of said heating element for providing an electrical characteristic representative of said temperature; signal generator means operative to provide an enabling signal output within an interval near the commencement of each cycle of said power source said oUtput having an amplitude alterable about a predetermined threshold level in response to the variable electrical characteristic of said sensor means; means for coupling said signal generator means in phase coincidence with said power source; and triggering means responsive to the output of said signal generator means, coupled with said switching means gate and operable to cause its activation upon receipt of a said enabling signal at said threshold value.
Claim 22
Independent Claim
182 words
A system for controlling the thermal output of an electrical heating element comprising: a source of oscillating electrical power coupled with said heating element; gated switching means operative to conduct an electrical current between said power source and said heating element upon receipt of a forward biasing gating signal and to continue to conduct until said current is discontinued; sensor means responsive to the temperature of said heating element for providing an electrical characteristic representative of said temperature; signal generator means coupled in phase coincidence with said source of electrical power for providing an enabling signal output within an interval near the commencement of each cycle of said power source said output having an amplitude alterable about a predetermined threshold level in response to the variable electrical characteristic of said sensor means and said signal generator means including signal clipping means for establishing the said threshold level; and triggering means responsive to the output of said signal generator means, coupled with said switching means gate and operable to cause its activation upon receipt of a said enabling signal at said threshold value.
Claim 23
Independent Claim
182 words
A system for controlling the thermal output of an electrical heating element comprising: a source of oscillating electrical power coupled with said heating element; gated switching means operative to conduct an electrical current between said power source and said heating element upon receipt of a forward biasing gating signal and to continue to conduct until said current is discontinued; sensor means responsive to the temperature of said heating element for providing an electrical characteristic representative of said temperature; signal generator means coupled in phase coincidence with said source of electrical power for providing an enabling signal output within an interval near the commencement of each cycle of said power source said output having an amplitude alterable about a predetermined threshold level in response to the variable electrical characteristic of said sensor means and said signal generator means including signal clipping means for establishing the said threshold level; and triggering means responsive to the output of said signal generator means, coupled with said switching means gate and operable to cause its activation upon receipt of a said enabling signal at said threshold value.
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) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |