Browsing Google Patents can be fun, if you like long sentences… It also sometimes reveals a hand-drawn Sankey diagram, like this one:
This is from a patent filing EP 0494399 A1 on “Process to direct and treat production waters in a paper factory with installation for treatment of waste paper” by German inventor Wilhelm Menges.
The diagram is for a paper recycling process. The “thickening filtrate arising from the dispersion of waste paper is directly fed to a biological waste water” treatment. This reduces the COD levels.
Flow quantities are shown in printed numbers. A lot of hand-written numbers refer to process elements.
