[StirCrazy]

Originally Posted by golf nut

You are looking at a cross section, there are four ports, 2 are not used and the drum has a port all the way through, it all works fine.

I could do it with just a 2 port switch you just change the approach angle and make the shuttle longer.

Paul

ok.. ya it makes sence, but you would need two units one for suction and one for discharge, how would you actuate the suction one? I could see it maybe working by using a self priming pump and installing it upside down, but now were talking a more expensive pump which will require more maintance and is supseptable to dammage from depris.

I think the simplest way still is by using two actuated ball valves. 5 second switch over ports are never blocked while switching over so even if there out of sync by a few seconds it will still work fine. one timer can seitch both. with two timers one for the actuaters and one for the pump you can get your 5 hours one way, 1 hour dead, 5 hours the other way easily and you can customize your flow very easily also.

but to get a true lamaner flow accross the tank its going to take a few holes in each end. I am looking at six 3/4" bulkheads on each end of a 30 gal tank a bigger tank would use bigger bulkheads but I would still use at least six on each end. so this could get expensive for drilling. then you can size your pump output so you get no more than 2 or 3 PSI at the output of the bulkheads so you don't blast anything. this combined with the suction on the other side will make the nice current through the tank.

If I had to I could dig out my fluid dynamic books and figure it out but it is a lot of calculations and sometimes FD makes my brain hurt thermal dynamics is a lot easier for me some times it is more easy to put a bypass to the sump on the outlet of the pump and just adjust it to get the strengh of flow your after.. I know its a lazy aproach but it works

Steve