US3798413A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proportional temperature control device
Assignee: TE Connectivity Corp
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Filing: 1973-05-04
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Granted: 1974-03-19
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Expires: 1993-05-04
Abstract
Abstract A device for maintaining a relatively constant temperature in an enclosure has a polyconductor connected in parallel to a first resistance element within the enclosure to be heated. The polyconductor is connected in series to a second resistance element located outside of the enclosure and this circuit is connected to a source of current which will cause the first resistance element to heat the enclosure as current passes therethrough; when the transition temperature of the polyconductor is reached, the first resistance element is shunted by the change in conductive state of the polyconductor and heating thereby is proportionally reduced in order to maintain the temperature within the enclosure at the transition temperature of the polyconductor.
Inventors
- 👤 D Kahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:16
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/1906
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
275 words
A proportional temperature control device adapted to be connected to a source of current to produce a temperature control cycle for maintaining the temperature in an enclosure at a relatively constant level, said device comprising a first electrical resistance element in said enclosure for heating the interior Of the enclosure when connected to said source of current, a polyconductor connected in parallel with said first electrical resistance element in said enclosure, and a second resistance element located outside of said enclosure and connected in series with said polyconductor whereby, when said first resistance element is connected to said source of current said first resistance element is heated, in accordance with Joule''s law, thereby raising the temperature within said enclosure and of said polyconductor until the transition temperature of the latter is reached, whereupon said polyconductor becomes increasingly conductive and increasingly shunts said first resistance element to permit said first resistance element, said enclosure and said polyconductor to cool, thereby increasing the resistance of the polyconductor and allowing said first resistance element to produce increased heat and repeat the temperature control cycle; said second resistance element having a resistance value which is less than that of said first resistance element, and said polyconductor being selected to have a resistance value below its transition temperature which is substantially higher than that of said first resistance element and a resistance value above its transition temperature which is at least several orders of magnitude less than its higher resistance value whereby the sum of the resistances of said polyconductor and said second resistance element above said transition temperature is comparable to the resistance value of said first resistance element.
Claim 2
Dependent Claim
275 words
A proportional temperature control device adapted to be connected to a source of current to produce a temperature control cycle for maintaining the temperature in an enclosure at a relatively constant level, said device comprising a first electrical resistance element in said enclosure for heating the interior Of the enclosure when connected to said source of current, a polyconductor connected in parallel with said first electrical resistance element in said enclosure, and a second resistance element located outside of said enclosure and connected in series with said polyconductor whereby, when said first resistance element is connected to said source of current said first resistance element is heated, in accordance with Joule''s law, thereby raising the temperature within said enclosure and of said polyconductor until the transition temperature of the latter is reached, whereupon said polyconductor becomes increasingly conductive and increasingly shunts said first resistance element to permit said first resistance element, said enclosure and said polyconductor to cool, thereby increasing the resistance of the polyconductor and allowing said first resistance element to produce increased heat and repeat the temperature control cycle; said second resistance element having a resistance value which is less than that of said first resistance element, and said polyconductor being selected to have a resistance value below its transition temperature which is substantially higher than that of said first resistance element and a resistance value above its transition temperature which is at least several orders of magnitude less than its higher resistance value whereby the sum of the resistances of said polyconductor and said second resistance element above said transition temperature is comparable to the resistance value of said first resistance element.
Claim 3
Dependent Claim
86 words
The device as defined in Claim 1 wherein the transition of said polyconductor from its high resistance value to its low resistance value is abrupt, occurs over a temperature span of approximately 1C, and is proportional within that span, whereby the shunting of said first resistance element is proportional within said span to proportionally control the production of heat by said first resistance element and thereby maintain the temperature in said enclosure at a relatively constant level substantially equal to the transition temperature of said polyconductor.
Claim 4
Dependent Claim
14 words
The device as defined in claim 2 wherein said polyconductor is formed of VO2.
Claim 5
Dependent Claim
21 words
The device as defined in claim 2 wherein said polyconductor has a transition temperature within the range of 10C to 80C.
Claim 6
Dependent Claim
42 words
The device as defined in claim 4 wherein said first resistance element has a value of 7 ohms, said second resistance element has a value of 6 ohms and said polyconductor has a resistance value of 700 ohms below its transition temperature.
Claim 7
Dependent Claim
262 words
A proportional temperature control device for maintaining a predetermined temperature in a chamber comprising, a source of current, an enclosure defining a chamber to be heated, a first electrical resistance element positioned within said chamber and electrically connected to said source of current, a polyconductor and a second electrical resistance element electrically connected in series to each other and connected in parallel to said first resistance element, said second resistance element being located outside of said chamber and said polyconductor being located inside of said chamber and formed of a polyconductive material having the characteristic that its electrical resistance value at temperatures below a predetermined transition temperature is at least several orders of magnitude larger than its resistance value at temperatures above said transition temperature, said material being selected to have a resistance value below its transition temperature which is substantially higher than the resistance velue of said first resistance element and to have a transition temperature which is the same as the temperature which is to be maintained in said enclosure, with the transition in resistance thereof occurring relatively abruptly at said transition temperature over a temperature span of approximately 1*C whereby current supplied to said first resistance element from said current source heats said first resistance element in accordance with Joule''s law until the temperature in said chamber reaches said transition temperature at which point said polyconductor becomes increasingly conductive and proportionally shunts said first resistance element over said 1*C span thereby to proportionally control heat production by said first resistance element and maintain said predetermined temperature in said chamber.
Claim 8
Dependent Claim
262 words
A proportional temperature control device for maintaining a predetermined temperature in a chamber comprising, a source of current, an enclosure defining a chamber to be heated, a first electrical resistance element positioned within said chamber and electrically connected to said source of current, a polyconductor and a second electrical resistance element electrically connected in series to each other and connected in parallel to said first resistance element, said second resistance element being located outside of said chamber and said polyconductor being located inside of said chamber and formed of a polyconductive material having the characteristic that its electrical resistance value at temperatures below a predetermined transition temperature is at least several orders of magnitude larger than its resistance value at temperatures above said transition temperature, said material being selected to have a resistance value below its transition temperature which is substantially higher than the resistance velue of said first resistance element and to have a transition temperature which is the same as the temperature which is to be maintained in said enclosure, with the transition in resistance thereof occurring relatively abruptly at said transition temperature over a temperature span of approximately 1*C whereby current supplied to said first resistance element from said current source heats said first resistance element in accordance with Joule''s law until the temperature in said chamber reaches said transition temperature at which point said polyconductor becomes increasingly conductive and proportionally shunts said first resistance element over said 1*C span thereby to proportionally control heat production by said first resistance element and maintain said predetermined temperature in said chamber.
Claim 9
Dependent Claim
60 words
The device as defined in claim 6 wherein said second resistance element has a predetermined resistance value and said polyconductor has a low resistance value above said transition temperature wherein the sum of the resistances of said polyconductor and said second resistance element above said transition temperature is approximately the same as the resistance value of said first resistance element.
Claim 10
Dependent Claim
30 words
The device as defined in claim 6 including a third resistance element located outside of said enclosure and connected in series between said current source and said first resistance element.
Claim 11
Dependent Claim
21 words
The device as defined in claim 6 wherein said polyconductor has a transition temperature within the range of 10C to 80C.
Claim 12
Dependent Claim
14 words
The device as defined in claim 9 wherein said polyconductor is formed of VO2.
Claim 13
Dependent Claim
50 words
The device as defined in claim 10 wherein said current source comprises a 6.3 volt source, said first resistance element has a value of 7 ohms, said second resistance element has a value of 6 ohms, and said polyconductor has a resistance value of 700 ohms below its transition temperature.
Claim 14
Dependent Claim
27 words
The device as defined in claim 7 wherein the resistance value of said second resistance element is less than the resistance value of said first resistance element.
Claim 15
Dependent Claim
27 words
The device as defined in claim 7 wherein the resistance value of said second resistance element is greater than the resistance value of said first resistance element.
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) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |