scale-free [electric kettle]


hey!~ I am very stuck, someone please help me!...

I am supposed to traslater this phrase

"Concealed element stays clean and scale-free", but dont really understand what scale-free means here, it is from a manual for an electrical kettle...

Checked on the web too, but couldnt find any clear definitions... from my impression the word would mean "with no limitation"??? but that doesnt reply for the electrical kettle at al... so please help me!~ :confused:
  • Oh, so it was that kind of scale! ...i was totally wrong

    ...that was actually my first posting, was really worried that i wouldnt get a reply... thank you so much Teddy! :)
    What is the kettle used for? The answer to this question, I think, is key to understanding the specific meaning of scale in this case. I assure you it is not a measuring device in this instance.

    Orange Blossom
    Kettles have an element which is a coil of metal tubing or wire that is heated electrically.

    In some kettles this element is exposed directly to the water to heat the water.
    In more modern kettles the element is concealed under a plate so the element heats the plate which heats the water.

    When water with impurities is boiled there is a tendency for mineral scale to deposit on the heating surface. This mineral buildup is kind of similar to stalegtites and stalegmites in caves where minerals evaporate out of the dripping water but the process is made much faster by heat.

    If the element is immersed in the water this scale builds up directly onto the element and this rapidly causes a loss of efficiency.

    wow, i did not know that there was so much knowledge in a kettle!! The manual i was translating shows the inside of the kettle where there is a concealed heating element matching exactly to what you said, Thank you so much ...,!!:)