Electrical resistance heater

• US 4,656,339 A
• Filed: 11/26/1984
• Issued: 04/07/1987
• Est. Priority Date: 08/28/1980
• Status: Expired due to Term

• Current Assignee: Calorique Limited
• Original Assignee: Flexwatt Corporation
• Inventors: Grise, Frederick G. J.
• Primary Examiner(s): Goldberg, E. A.
• Assistant Examiner(s): Walberg, Teresa J.
• Application Number:
  US06/674,698
• Time in Patent Office: 862 Days
• Field of Search: 219/301, 219/345, 219/503, 219/211, 219/212, 219/522, 219/528, 219/529, 219/541, 219/543, 219/544, 219/548, 219/549, 219/522, 219/553, 338/211, 338/212, 338/217, 338/293, 338/300, 338/308, 338/309, 338/319, 338/320, 338/330, 174/68.5
• US Class Current: 219/528
• CPC Class Codes: H05B 3/34 flexible, e.g. heating nets or webs
• CPC Class Codes: H05B 3/565 flat cables

Abstract

The heater of the present invention includes a paper or plastic substrate on which is printed a semi-conductor pattern (typically a colloidal graphite ink) having (a) a pair of longitudinal stripes extending parallel to and spaced apart from each other and (b) a plurality of identical bars spaced apart from each other and extending between and electrically connected to the stripes. A metallic conductor (typically copper stripping) overlies each of the longitudinal stripes in face-to-face engagement therewith, and the conductors are held in tight engagement with the stripes by a sealing layer that overlies the metallic conductors and is sealed, at opposite sides of the semi-conductor stripe associated with the particular metallic conductor, to portions of the substrate that are free from the printed semi-conductor pattern.

Claims

1. An electrical heating device comprising:

a substrate having an electrically insulating surface,

a semi-conductor pattern carried on said surface, said pattern comprising a mixture of conductive particles in a binder,

an organic plastic sheet overlying said surface and said pattern, and

a pair of planar conductors electrically engaging said semiconductor pattern,

said device being characterized in that

said semi-conductor pattern includes a pair of spaced-apart conductor connection portions and a plurality of elongated heating portions extending between and electrically connected to said conductor connection portions,

said semi-conductor pattern is arranged such that elongated portions of said substrate that are free from said semi-conductor pattern are provided between adjacent ones of said heating portions,

said organic plastic sheet is in face-to-face engagement with and is bonded to said elongated portions of said substrate that are free from said semi-conductor pattern, and

each of said conductors overlies and is in face-to-face engagement with a respective one of said conductor connection portions.

2. The heating device of claim 1 wherein the resistivity of said conductor portions of said semi-conductor pattern is less than that of said heating portions.

3. The heating device of claim 2 wherein the thickness of said conductor portions of the semi-conductor pattern is greater than that of the heating portions of the semi-conductor pattern.

4. The device of claim 1 wherein the width of the portion of each of said conductors within the bounds of the respective conductor connection portion that said each conductor overlies is less than that of the respective conductor connection portion.

5. The device of claim 1 wherein said semi-conductor pattern is arranged to provide longitudinally-extending portions of substrate that are free from said semi-conductor pattern along opposite side edges of said substrate with said sheet is in face-to-face engagement with and to which said sheet is bonded.

6. An electrical heating device comprising:

a substrate having an electrically-insulating surface

a semi-conductor pattern carried on said electrically-insulating surface of said substrate, said pattern including a pair of conductor connection portions spaced apart from each other, and a plurality of heating portions spaced apart from each other and extending between and electrically connected to said conductor connection portions, said connection portions and said heating portions being arranged so as to provide portions of said substrate between adjacent ones of said heating portions and closely adjacent edges of said connection portions that are free from said semi-conductor pattern;

a pair of conductors, each of said conductors having a resistivity less than that of said heating portions and said connection portions and overlying and being in direct electrical engagement with a different one of said pair of connection portions; and

an electrically-insulating sealing sheet overlying at least one of said conductors and the said connection portions associated therewith, said sheet being sealed at the opposite sides of said one conductor to said closely adjacent portions of said substrate that are free from said semi-conductor pattern, whereby said sealing sheet holds said one conductor in tight engagement with the associated said connection portions.

7. The heating device of claim 6 wherein said sealing sheet extends substantially the length and width of said substrate and is bonded thereto.

8. The heating device of claim 6 wherein said semiconductor portion is arranged to provide portions of said substrate that are free from said semi-conductor pattern along opposite edges of each of said heating portions and along transverse and longitudinal edges of said substrate, and said sealing sheet is bonded to all of said portions that are free from said pattern.

9. An electrical heating device comprising:

a substrate having an electrically insulating surface;

a semi-conductor pattern comprising a mixture of conductive particles in a binder carried on said electrically insulating surface of said substrate,

said semiconductor pattern including a pair of spaced-apart conductor connection portions extending generally longitudinally of said device and a plurality of spaced-apart elongated heating portions extending between and electrically connected to said conductor connection portions,

said pattern being arranged such that, at each end of each of said heating portions, the portion of the respective one of said conductor connection portions associated with said each heating portion and connected thereto extends longitudinally of said device beyond at least one side edge of the said each heating portion whereby the width of said each heating portion is less than the longitudinal length of the portion of the conductor connection portions with which it is associated, and;

a pair of spaced-apart conductors extending generally longitudinally of said device, each of said conductors having a resistivity less than that of said heating portions and said connector connection portions and overlying in face-to-face engagement and being in direct electrical engagement with a different one of said pair of conductor connection portions.