US5177341A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thick film electrically resistive tracks
Assignee: EMI Group Ltd
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Filing: 1988-02-24
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Granted: 1993-01-05
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Expires: 2008-02-24
Abstract
Abstract In a thick film water track, irrespective of track thickness or the material of which the track is constructed, the optimum track width is found to be in the range of from 1.2 mm to 2.1 mm. Further, for a given resistance, the track is longer and may be conformed to a pattern to give improved temperature distribution. Additionally disclosed is a heating element having a number of thick film electrically resistive tracks applied to the surface of an electrically insulative substrate and a switch for selectively connecting one or more of the tracks to a power supply. The resistance and hence the operating temperature of the heating element may be varied by changing the track or tracks connected to the switch.
Inventors
- 👤 Simon Balderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:43
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/68; H05B3/74; H05B3/748; H05B3/20; H05B3/22; H05B3/26; H05B2203/00; H05B2203/002; H05B2203/003; H05B2203/005; H05B2203/013; H05B2203/017
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
70 words
A heating unit comprising an elongate thick film electrically resistive track of substantially constant width of between 1.2 and 2.1 millimeters along its length, to permit substantially even heat distribution over the length and width of the track, the length to width ratio being at least 10 to 1, the track being supported on a substrate of electrically insulative material, the track being configurated to achieve a predetermined heating profile.
Claim 2
Dependent Claim
70 words
A heating unit comprising an elongate thick film electrically resistive track of substantially constant width of between 1.2 and 2.1 millimeters along its length, to permit substantially even heat distribution over the length and width of the track, the length to width ratio being at least 10 to 1, the track being supported on a substrate of electrically insulative material, the track being configurated to achieve a predetermined heating profile.
Claim 3
Dependent Claim
21 words
A heating unit according to claim 1 wherein the width of said track is in the range 1.5 to 2.0 millimeters.
Claim 4
Dependent Claim
34 words
A heating unit according to claim 1 comprising a plurality of said tracks, said plurality of tracks being supported on said substrate of electrically insulative material and connected electrically in parallel with one another.
Claim 5
Dependent Claim
34 words
A heating unit according to claim 2 comprising a plurality of said tracks, said plurality of tracks being supported on said substrate of electrically insulative material and connected electrically in parallel with one another.
Claim 6
Dependent Claim
68 words
A heating unit according to claim 1 comprising a plurality of said thick film electrically resistive tracks supported on the surface of said electrically insulative substrate and switching means for selectively connecting one or more of said tracks to a power supply whereby the resistance and hence the operating temperature of said heating unit may be varied by changing the track or tracks connected to said switching means.
Claim 7
Dependent Claim
18 words
A heating unit according to claim 3 wherein each of said plurality of tracks has a different resistance.
Claim 8
Dependent Claim
18 words
A heating unit according to claim 4 wherein each of said plurality of tracks has a different resistance.
Claim 9
Dependent Claim
18 words
A heating unit according to claim 5 wherein each of said plurality of tracks has a different resistance.
Claim 10
Dependent Claim
26 words
A heating unit according to claim 6 wherein at least one of said plurality of tracks is made of a different material from the other tracks.
Claim 11
Dependent Claim
26 words
A heating unit according to claim 7 wherein at least one of said plurality of tracks is made of a different material from the other tracks.
Claim 12
Dependent Claim
26 words
A heating unit according to claim 8 wherein at least one of said plurality of tracks is made of a different material from the other tracks.
Claim 13
Dependent Claim
44 words
A heating unit according to claim 5 wherein at least one of said plurality of tracks is made of a material having in the range of from 0° C. to 550° C. a temperature coefficient of resistance in excess of 0.006 per degree C.
Claim 14
Dependent Claim
44 words
A heating unit according to claim 6 wherein at least one of said plurality of tracks is made of a material having in the range of from 0° C. to 550° C. a temperature coefficient of resistance in excess of 0.006 per degree C.
Claim 15
Dependent Claim
44 words
A heating unit according to claim 9 wherein at least one of said plurality of tracks is made of a material having in the range of from 0° C. to 550° C. a temperature coefficient of resistance in excess of 0.006 per degree C.
Claim 16
Dependent Claim
39 words
A heating unit according to claim 5, said operating temperature being determined by the resistance of a track connected to said switching means wherein said operating temperature may be altered by changing the track connected to said switching means.
Claim 17
Dependent Claim
39 words
A heating unit according to claim 6, said operating temperature being determined by the resistance of a track connected to said switching means wherein said operating temperature may be altered by changing the track connected to said switching means.
Claim 18
Dependent Claim
39 words
A heating unit according to claim 9, said operating temperature being determined by the resistance of a track connected to said switching means wherein said operating temperature may be altered by changing the track connected to said switching means.
Claim 19
Dependent Claim
39 words
A heating unit according to claim 12, said operating temperature being determined by the resistance of a track connected to said switching means wherein said operating temperature may be altered by changing the track connected to said switching means.
Claim 20
Dependent Claim
37 words
A heating unit according to claim 5, wherein said operating temperature may be altered by changing the number of tracks electrically connected in parallel to one another, said number of tracks being connected to said switching means.
Claim 21
Dependent Claim
37 words
A heating unit according to claim 12, wherein said operating temperature may be altered by changing the number of tracks electrically connected in parallel to one another, said number of tracks being connected to said switching means.
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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) | 1996-01-05 | 1996-07-06 | 1997-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-01-05 | 2000-07-06 | 2001-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-01-05 | 2004-07-06 | 2005-01-05 | $7700.00 | Window Closed / Lapsed |