Has anyone used or installed a venturi valve?
Venturi valves use, in shitty layman's terms, differences in pressure to suction fluid, one way, through a valve. An example is an autobailer in small sailboats that suck water through a venturi valve in the bottom of the hull (the quick moving water in the lake has a lower "pressure" than the still water in the bottom of the boat). The KC-10 uses venturi valves all over it's many fuel tanks, which is what originally gave me this idea.
My shortie is too small for a generator/inverter/air conditioner, so I'm installing a swamp/evaporative cooler in the leading edge of the bus roof (where it used to say SCHOOL BUS). The idea is to use my massive water tanks (40 gallons) and the water pump for the house system to pump water up there using a PEX line, where it will trickle over evaporative cooling material and into a reservoir (using the induced wind from driving to evaporate the liquid). This reservoir will drain into a venturi valve, attached to the original PEX line, such that it will drain into the line, but the line will not drain into the reservoir.
Is this possible? Are there any premade solutions for this? I don't mind getting my hands dirty and making my own, but I figured I'd check here first.