G'day ALL
i am about to build one , pvc pressure piping and fittings from Bunnings, my plan was to keep it simple , easy to pull apart to clean or replace parts, so its a gunna suck it up and spit it out , no traps, one way valves or branch pieces, , the caps will be held in place by brass screws, no glue, so it can be dismantled , the pump plunger will be good old fashioned leather , easy to shape when wet and lubed with dripping , my thoughts on the operation is when you draw the handle/ plunger up, the compressed air needs to go somewhere so theres a little bit of play in the top assembly, vise versa , when you push the material out the inlet you need not to created a vacuum. the unit will basically suck up liitte rocks gemstones nuggets etc all held in a muddy suspension then discharged out the sucker end into a bucket , we'll thats the theory will post more on how it works in the field