I'm fairly illiterate when it comes to Engineering, so please understand I have pretty much 0 idea what I'm talking about.
I'm having to build a seawater distillation device for school, and we decided to go with reverse osmosis, to try and achieve this. (Reverse osmosis being the filtering of salt from water using massive applied pressure)
What I'm looking for, is a part that's a "Screw Piston" (I have no idea what it's actually called). So it's like a hydraulic piston, except the piston rod is threaded like a screw, so you as you tighten the screw, it applies a downward pressure. Here's a crudely made diagram of what I'm talking about
I'm almost certain that something like this exists, (I mean if not, than I guess I should probably hire a patent lawyer and get to work) but since I have no idea what it's actually called, being mechanically illiterate, I have no idea how to search it up or where I could find something like this. I'd really appreciate help telling me what it's called and where I could possibly get one.
So my TL;DR is, what the heck is this thing called, and where do you think I could buy one? A giant thank you in advance to anyone who bothers to read this and answers!
(btw the reason I need a screw for the piston is that I need the mechanical advantage because reverse osmosis requires like 8000 pounds for force to filter the water.)