A LFS had it and talked me into buying it. It was expensive but it's so simple it was totally worth it. Basically you add eggs to the outside ring, and 24 hours later the brine are in the center strainer with all of the egg capsules left over on the outer ring.
https://www.amazon.co.uk/Hobby-21700-Artemia-Breeder/dp/B000RRSIP0
https://www.amazon.co.uk/Hobby-21700-Artemia-Breeder/dp/B000RRSIP0