Patent US3318386A successfully refreshed from Google Patents.
US4017715A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature overshoot heater
Assignee: Raychem Corp
•
Filing: 1975-08-04
•
Granted: 1977-04-12
•
Expires: 1995-08-04
Abstract
Abstract Described herein are self-regulating heating articles. The article comprises a constant wattage layer and a layer that exhibits a positive temperature coefficient of resistance (PTC layer). At its steady state condition, the heater is self-regulated by the switching or anomaly temperature T s of the PTC layer. However, the constant wattage layer has a higher resistance at temperatures below T s and heats first when the article is connected to a source of electrical power. Means are provided to impede the temperature increase in the PTC layer caused by the heating of the constant wattage layer so that it can heat above T s before the PTC layer rises to T s and reduces the current flow to the heater. Further increases in temperature render the PTC layer, for most purposes, non-conductive. Specific impeding means include an electrically conductive, but thermally insulating layer and means that provide for non-uniform heating of the PTC layer so that it remains conductive across a part of its thickness.
Inventors
- 👤 Wells Whitney
- 👤 David August Horsma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:23
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/146; H01; H01C; H01C7/00; H01C7/02; H01C7/027; Y; Y10; Y10S; Y10S174/00; Y10S174/08
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
135 words
A self-regulating heating article when connected to a source of electrical current having a layered structure comprising: a. a layer of electrically conductive material having a positive temperature coefficient of resistance (PTC layer) and an associated switching temperature T s ; b. an electrical heating layer of constant wattage material (CW layer) having a higher resistance below T s than does said PTC layer to which it is connected in series; c. electrical terminal connection for said heating article; and d. means for impeding the temperature increase in said PTC layer relative to said constant wattage layer when electrical connection is made to said source of current so that the PTC layer remains electrically conductive through a least a section of its thickness until the temperature of the CW layer rises above T s .
Claim 2
Dependent Claim
135 words
A self-regulating heating article when connected to a source of electrical current having a layered structure comprising: a. a layer of electrically conductive material having a positive temperature coefficient of resistance (PTC layer) and an associated switching temperature T s ; b. an electrical heating layer of constant wattage material (CW layer) having a higher resistance below T s than does said PTC layer to which it is connected in series; c. electrical terminal connection for said heating article; and d. means for impeding the temperature increase in said PTC layer relative to said constant wattage layer when electrical connection is made to said source of current so that the PTC layer remains electrically conductive through a least a section of its thickness until the temperature of the CW layer rises above T s .
Claim 3
Dependent Claim
24 words
An article according to claim 1 wherein said impeding means is a thermally insulating layer disposed between said CW layer and said PTC layer.
Claim 4
Dependent Claim
22 words
An article according to claim 2 wherein said insulating layer is an electrically conductive layer of lower resistance than said CW layer.
Claim 5
Dependent Claim
14 words
An article according to claim 3 wherein said insulating layer is a polymer foam.
Claim 6
Dependent Claim
25 words
An article according to claim 1 wherein said CW layer comprises a PTC material with a T s higher than that of said PTC layer.
Claim 7
Dependent Claim
25 words
An article according to claim 3 wherein said CW layer comprises a PTC material with a T s higher than that of said PTC material.
Claim 8
Dependent Claim
24 words
An article according to claim 2 further comprising a heat storage layer disposed on the side of the CW layer opposite said insulating layer.
Claim 9
Dependent Claim
13 words
An article according to claim 7 wherein said storage layer is electrically conductive.
Claim 10
Dependent Claim
15 words
An article according to claim 8 wherein said storage layer comprises a crosslinked crystalline polymer.
Claim 11
Dependent Claim
45 words
An article according to claim 3 comprising a second constant wattage layer disposed on the side of the PTC layer opposite said insulating layer, said 2nd CW layer below T s having a lower resistance than said CW layer but higher than said PTC layers.
Claim 12
Dependent Claim
36 words
An article according to claim 3 comprising a second thermally insulating layer and a second constant wattage layer disposed on the side of the PTC layer opposite said first PTC layer and said first insulating layer.
Claim 13
Dependent Claim
69 words
An article according to claim 2 having a second PTC layer disposed between said insulating layer and said CW layer, said second PTC layer having a T s higher than that of said first PTC layer and a second constant wattage layer disposed on the side of said first PTC layer opposite said insulating layer, said second constant wattage layer having a lower resistance than said first CW layer.
Claim 14
Dependent Claim
56 words
An article according to claim 1 wherein said article comprises a pair of CW layers disposed on either side of said PTC layer and a pair of descrete electrodes substantially parallel, each member of said pair being embedded in a different CW layer and diagonally spaced apart from each other on either side of said article.
Claim 15
Dependent Claim
69 words
An article according to claim 1 wherein said article comprises a pair of CW layer disposed on either side of said PTC layer and a pair of substantially parallel electrodes, each member of said pair being embedded in a different CW layer and spaced apart to define a line normal to the plane of the layers and near one of the edges of the article defined by the layers.
Claim 16
Dependent Claim
29 words
An article according to claim 1 wherein said article comprises a pair of CW layers on either side of said PTC layer, said CW layers having a non-uniform thickness.
Claim 17
Dependent Claim
27 words
An article according to claim 15 wherein the thickness of said CW layers increases from a minimum thickness at one edge to a maximum at the other.
Claim 18
Dependent Claim
30 words
An article according to claim 1 wherein said article comprises a pair of CW layers disposed on either side of said PTC layer, said PTC layer having a non-uniform thickness.
Claim 19
Dependent Claim
19 words
An article according to claim 17 wherein said PTC layer is thicker at its midsection than at either edge.
Claim 20
Dependent Claim
10 words
An article according to claim 1 that is heat recoverable.
Claim 21
Dependent Claim
10 words
An article according to claim 2 that is heat recoverable.
Claim 22
Dependent Claim
10 words
An article according to claim 3 that is heat recoverable.
Claim 23
Dependent Claim
10 words
An article according to claim 4 that is heat recoverable.
Claim 24
Dependent Claim
10 words
An article according to claim 5 that is heat recoverable.
Claim 25
Dependent Claim
10 words
An article according to claim 6 that is heat recoverable.
Claim 26
Dependent Claim
10 words
An article according to claim 7 that is heat recoverable.
Claim 27
Dependent Claim
10 words
An article according to claim 8 that is heat recoverable.
Claim 28
Dependent Claim
10 words
An article according to claim 9 that is heat recoverable.
Claim 29
Dependent Claim
10 words
An article according to claim 10 that is heat recoverable.
Claim 30
Dependent Claim
10 words
An article according to claim 11 that is heat recoverable.
Claim 31
Dependent Claim
10 words
An article according to claim 12 that is heat recoverable.
Claim 32
Dependent Claim
10 words
An article according to claim 13 that is heat recoverable.
Claim 33
Dependent Claim
10 words
An article according to claim 14 that is heat recoverable.
Claim 34
Dependent Claim
10 words
An article according to claim 15 that is heat recoverable.
Claim 35
Dependent Claim
10 words
An article according to claim 16 that is heat recoverable.
Claim 36
Dependent Claim
10 words
An article according to claim 17 that is heat recoverable.
Claim 37
Dependent Claim
10 words
An article according to claim 18 that is heat recoverable.
Claim 38
Dependent Claim
12 words
An article according to claim 13 wherein said electrodes are strip electrodes.
Claim 39
Dependent Claim
13 words
An article according to claim 13 wherein said electrodes are braided tubular electrodes.
Claim 40
Dependent Claim
23 words
An article according to claim 13 wherein said CW layers have substantially the same resistance and said resistance is uniform across their width.
Claim 41
Dependent Claim
32 words
An article according to claim 39 wherein said CW layers comprise a material having a positive temperature coefficient of resistance with a switching temperature T s above that of said PTC layer.
References Cited (Backward Citations)
US3067311A
Cited
US3311862A
Cited
US3351882A
Cited
US3413442A
Cited
US3412358A
Cited
US3375774A
Cited
US3535484A
Cited
US3591526A
Cited
US3673121A
Cited
US3793716A
Cited
US3823217A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |