How to input objects into the bottom of a water tank.

MrSponge

Iy needs to be bigger for more than one person, but this will need supervison. A paddling pool can be just as dangerous. However im concered about the mechanisms, so can you help me improve the mechanisms?

DaveC426913

What is wrong with something as simple as a tube/hopper slightly wider than the balls, and a stick of wood to push them down the tube?

You could tilt the tube (delivery system) over 45 degrees so that the end of the tube (hopper) is far way from the watertub (game zone) and it would still work. A quick shove of the stick (dispenser apparatus) would eject a ball into the game zone.

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Danger

I must admit, Dave, that you have me beat all sideways on simplicity. I do have a modification of yours in mind already, which would automate the stick-poking very easily. The elegance of your solution almost makes me embarrassed to post the one that I came up with, but I'm going to anyhow because I've been drawing it all day. (Still trying to get used to Inkscape.) Here it is:

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I'll post the explanation tomorrow.

MrSponge

That is a really beautiful design, alot what I was thinking. Just two questions though...

Why the aquarium pump?
When the balls from the hopper have entered the ball wells and rotated to under the water tank how will it float if there is no water under it to help it float? If it would already have water in it from the previus cycle, how will the ball fit in the ball well in the first place if there is water in it resisting to sit in the well completely. If it is not in completly it will be scraping the top of the sump tank and to the eneterance of the water tank.

I really do apreciate the time you have spent drawing the diagram, thankyou.

MrSponge

I believe that could work quiete well. Thanks you for spending time to make that diagram.

DaveC426913

He is using a sump chamber to hold the leakage. The aquarium pump would come on when the float switch is activated, to pump extra water out of the sump (or bilge, as we sailors might call it).

You can rest assured the water will rush in and displace the ball. There is no doubt about that.

This is where I think the design will be challenging. I think that, unless you get deeply into water-tight seals and tolerances and such, the mechanism will hemorrhage water. That's what the sump pump is for, but my gut says the leakage rate will overwhelm the pump.

Danger

Luckily, it appears that I don't have to explain most of it. I expected questions about the very aspects that you both mention.
Dave has one thing backward, though; the pump runs until the float drops to the level of the well bottoms (to prevent the pump from running dry). The 2mm drains in the wells let them empty so the balls just drop in. If a ball protrudes a bit, it will simply cam down when it gets to an overhead obstruction. I hadn't actually thought of having a cover on the sump tank, but it's a good idea to keep debris out.
The input port in the bottom of the main tank is surrounded by a Teflon (or other slippery plastic) gasket. An O-ring could be used, but I don't know how well it would stand up to shear stresses imparted by the carousel rotating. I obviously haven't done any calculations (and don't even know how to), but my gut instinct says that the gph of the pump should exceed the leakage rate. I defer to Dave's gut on that, though, since he obviously has more experience with bilge pumps and sealing. If he's right, I'm pretty much hooped.
The only reason that I used a ramp (actually more of an inverted trough) as the finger guard, rather than a simpler cover, is to deflect the balls to the centre and thus give better surface distribution.
The automation idea that I have for Dave's design is to simply cut a slot in the feed tube above the water line to accommodate the spokes of a motorized "paddle wheel" to force the balls down.

DaveC426913

Nah. It's possible that your idea is more water-tight than I'm getting from the diagram.

My gut is simply synonymous with 'I have no idea, but can't resist having an opinion'.

Yeah. That would be good.

The crux of my idea is simply that there's no need for the water-zone and air-zone to be artificially kept separate. They do that naturally at the waterline.

Danger

There are probably several ways to do this that none of us has even thought of.
As it stands, though, I would recommend using Dave's design with my hopper and power feed wheel. I humbly suggest, as well, that you incorporate my notion of a trough to centre the balls in the tank. That's just to prevent them from accumulating on one side.

DaveC426913

Yep. I noticed that missing in the original design too. All the balls will come up in the same place, without some sort of randomizer.

The patented DaveC426913 stick-propelled delivery system allows a primitive version of this. You can vary the amount of thrust you apply. The downside is that you are as likely to show several balls out at once.

Simon Bridge

OP seems to have decided that changing fluid may be the answer...
http://www.physicsforums.com/showthr...=1#post4352989
I have a feeling that something like Simanek's type 4 buoyancy motor was originally thought of.

Danger

Until you resurrected this dinosaur, I didn't even think of this being the same guy. I've been trying to figure out what the hell he was hoping to accomplish with the ferrofluid tank. It nagged at me as being somewhat familiar, but I couldn't figure out why until now. Thanks.
I suppose that now I have to go and pay more attention to his new threads.

Simon Bridge

I know it's old but there was such a lot of creative effort I figured the same people would be interested in developments ;)

Danger

I am; unfortunately Dave is no longer a member of the PF community.

Simon Bridge

Well, the post #20 design, with a return mechanism, would be one way to spoof a buoyancy pmm.
These things can be quite neat as art - a water-feature?

Dave's was a simpler idea which also addressed, indirectly, the main begged question: why not just push the balls in? Why gravity feed? (The grav feed is a common requirement for the buoyancy pmm designs.) Your's has the needed distractions.