| abstract |
An electric water heater of high power density, suitable for use in a kettle or jug, or in a shower heater, has a surface which, in use, will be exposed to the water being heated. That surface is provided with adjacent regions which have different surface tension properties. Preferably the surface is provided with a two-phase or multi-phase coating, comprising particles that provide nucleation sites for bubbles and a matrix acting to disrupt the growth of the bubbles. The coating allows a significant reduction (ca. 20 db) in noise level to be achieved. |