Scale reducing heating element for water heaters
US5774627A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 31, 1996 |
| Grant date | Jun 30, 1998 |
| Priority date | — |
| Expiry date | Jan 31, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B3/48
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An extended life electrical heating element for a water heater includes a coiled heating resistance wire having a uniform power output per coil turn. Where the heating resistance wire passes through the sheath at critical areas, e.g. return bends, the number of coil turns per unit length of element is reduced to reduce thermal power output per unit length of the element. The number of coil turns per unit length of element in bend areas may be reduced by simply stretching the coiled heating wire to attain the desired length of resistance wire per unit length of the element. Resistance wires of differing heat output per unit length may be combined with different degrees of stretching to achieve the desired element temperatures. The reduced power at the bend portions reduces element temperature to reduce hard water scaling and significantly extend the life of the element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.