my bad, the pic didn't show how it functions very well. the below pic shows the inlet to the left, outlet to the right, & brass filling cap (i might reverse the inlet & outlets, which would result in the flow i erroneously thought might invite a vortex. there's just too much turbulence in the small hi-flow container & the inlet is perpendicular to the likely axis of rotation of the drain flow. a tangential inlet & large free volume (no baffles) would certainly invite the vortex demons into the tank.
the bad news: i filled it up, plugged the ends, & "simulated" a bleed. i had to shake the thing back & forth violently to get most of the air out. i might have to break my silicone seal & chop that stem down to a nut with my Dremel (AHHG!!! *crouches in fetal position protecting g401n*).