I am trying to find a way to create a system that continuously transports Nerf foam balls up a hose to some flywheels. In the photo below you can see the basic setup with the air pump on one end blowing into a Y connector which has a funnel connected to it, then a hose and finally the flywheels at the far end. (The funnel/hopper currently does not have an agitator but that’s going to be engineering problem #2 so I am ignoring it for now).
When I drop a single ball down the funnel and then turn on the pump everything works great. When I turn on the pump first and then try to drop a ball down the funnel, there is significant blowback pushing the ball back out. If I manually push the ball down the Y piece of course it shoots out just fine. If I disconnect the outgoing hose from the Y piece and run the test there is no blowback and again the balls come out as expected. Question: how can I fix this and get a continuous feed of balls down the funnel and up to the flywheels?
Some parameters: the end goal is something like a stationary mini-gun where you just keep dumping balls into a large hopper. I know I could seal off the hopper and pressurize it similar to what Savage did for his ping pong mini-gun, but I want this to be an open system! The hopper needs to be lower than the flywheel - maybe 3 feet or so. That’s not much but it precludes a pure gravity fed approach.