Safety circuit for heating devices using PTC wire
US6355912B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 13, 2000 |
| Grant date | Mar 12, 2002 |
| Priority date | — |
| Expiry date | Jan 13, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B2203/035
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A heating appliance such as an electric heating blanket having a control circuit which controls the application of power to the heating element of the blanket based on the condition of the heating element. The circuit senses the voltage at the end of the heating element in order to determine if the heating element has a short or an open circuit condition therein. Under normal conditions, the sensed voltage will be above a predetermined threshold value. If the sensed voltage falls below the threshold value, the control circuit shuts off power to the heating element. The control circuit will keep power off until the fault condition has been corrected and power has been removed and reapplied to the control circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.