Electric heater
US4931621A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 11, 1988 |
| Grant date | Jun 5, 1990 |
| Priority date | — |
| Expiry date | Aug 11, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B2213/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In the case of an electric heater, particularly a radiant heater for glass ceramic hotplates, there are several spirally nested heating resistors, whereof one heating resistor continuously passes through in the central field in such a way that it forms two nested spirals (10, 17) distributed approximately uniformly over the entire heating field, but which are not directly adjacent to one another and instead between their spiral turns (20, 21) is provided at least one spiral turn of a further, spirally wired heating resistor. This makes it possible in simple manner to make the length of said first-mentioned heating resistor much larger, so that it has a very high rated power, but can still be safely laid or wired in the heating field without any risk of local overheating.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.