Hmmmmm...I built a cassava grater for a client a few years ago. That was interesting and fun.

For separating the skin and seeds from the pulp and juice of tomatoes, the best ting I ever used was the old-fashioned Foley Food Mill. Now this is a simple hand-operated item for home canning, not a production unit, but if I needed to make a production unit I'd use the same concept as the Foley but make it bigger and faster.

The Foley uses a conical perforated-metal screen with a wiper that is angled so it forces the tomato pieces through the screen as the handle is turned. There is another wire rod wiper on the bottom of the screen that continuously clears the screen of pulp. The skins stay behind and you have to pick them out frequently or they jam things up. Because of that, I usually blanch and peel the tomatoes before running them through the Foley. On a commercial unit I'd work out a secondary scraper that lifted the peels off the screen and out of the hopper on a continuous basis. Alternately, you could first press the tomatoes through a coarse screen to shed the skins and then into a rotary screen press like the Foley to finish the pulping and straining operation.

Sounds like a fun project - I made a real mess out of a hundred pounds or so of cassava when I worked out the grater for the University, and I can only imagine the mess I could make developing a tomato strainer! :-)

Keep us posted on your progress with this, please.

Rich

Ivan Bailey
I raise a lot of tomatoes and can them usually but also make tomato sauce.
For canning I blanch the tomatoes, dump them in boiling water for a few minutes, then pop them in cold water and the skins come off very easily. Then I put them whole in canning jars and boil them for a half hour if they are still hot when they go into the jars.
For sauce you would first blanch and remove the skins and then use a wonderful little machine you wind the handle of to screw the tomatoes through any one of four sieves .it is good at getting out the seeds and doesn't waste too much pulp. The part sieved through will cook down pretty well in a couple of hours. The machine is called a Foly food mill and is pretty cheap and has three adjustable legs to sit it on top of various sized pots or bowls. Sorry this is not an electric machine but it works fairly quickly and stores compactly