It didn't stop him getting an international patent on
> counter-current continuous cooking, where you convert wood chips
> into paper pulp by letting them fall down through a rising stream of
> sodium hydroxide. solution. We did get international visitors. One > was
>
>formatting link>
> who'd invented the concurrent continuous digestor that my father
> eventually modified for counter-current operation. Johan had tried
> for some ten years to get it to work counter-current, and his
> company (Kamyr) never paid any royalty on my father's patent, though
> the industry adopted the process very rapidly.
But you don’t need to prove something works before getting a patent.
Thomas Edison put together the first working electric light-bulb. Did he get the patent on it? No, because that was already taken by Joseph Swan.