digester vs milk saucepan

digester

noun
  • A strong closed vessel in which bones or other substances may be subjected, usually in water or other liquid, to a temperature above that of boiling, in order to soften them. 

  • One who, or that which, digests. 

milk saucepan

noun
  • A small saucepan, often coated with Teflon etc, having a wide lip; typically used to heat milk for drinks 

How often have the words digester and milk saucepan occurred in a corpus of books? (source: Google Ngram Viewer )