Safety control circuit for electric water heater
US6646237B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Mar 5, 2002 |
| Grant date | Nov 11, 2003 |
| Priority date | — |
| Expiry date | Apr 25, 2022 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF24H15/156
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A safety control circuit for an electric water heater includes a voltage detection circuit, a current detection circuit, a load-resistance calculation unit, and a central processing unit. The load-resistance calculation unit calculates load-resistance reference value and dynamic load-resistance values based on voltage value and current value detected by the voltage detection circuit and the current detection circuit, respectively. The central processing unit determines whether there is water supplied to the electric water heater based on the load-resistance reference value and the dynamic load-resistance values sent to the central processing unit by the load-resistance calculation unit. When a difference between the two values is larger than a predefined value, the central processing unit drives a switch to turn off and thereby cut off power supply to the water heater.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.