On Saturday, August 2, 2014 4:28:42 PM UTC-4, Stormin Mormon wrote:
On 8/2/2014 4:03 PM, Frank wrote:





I think originally that there was no bladder in pressure tanks and they

just relied on the air space. They added bladders later since the air

will eventually dissolve in the water requiring air to be added frequently.



The one I saw briefly, had a doodad that looked

like a flying saucer with a hose. I think that's

designed to inject a small bit of air each time

the pump cycles.


I know there was more than one type. But I think they all need
some feedback/control mechanism to keep the air at the right level.
The air is supposed to be from where the gizmo is, up to the top of
the tank. If water rises above that, it triggers it to start pumping
air. Without feedback, if you just put some in each time, you still
wouldn't get it right and you could wind up with a tank full of air,
instead of half water.