1chicagodave wrote:(I have a similar humidifier)
Just had another thought....
If you can get underneath where the reservoir sits - there's that plastic 'pin' which pushes the plunger/valve up when reservoir is inserted. If that could be replaced with solenoid or 'servo-plunger' (I just made that up), you may be able to lower it, thus closing the plunger/drain whenever it's time to refill.
....this could probably be done with magnets alone (push to open, pull to close) to help maintain water-proofness.
DID YOU SAY MAGNETS?http://www.youtube.com/watch?v=EwVDDxoKBk4&hd=1
But seriously, I have performed the following test:
plastic bottle, made hole in bottom, feed water line into this hole, sealed pretty tight.
Plastic Pan, with a level of water in it.
Filled plastic bottle about halfway.
Placed mouth of plastic bottle into water in plastic pan, not touching the bottom, just on the surface to seal.
Result: Volume of liquid holds.
Next: Turn valve on to feed line.
Guess what happens? Even at full flow rate, volume of liquid remains constant in container.
This is probably obvious to a lot of people but, I think if I pull a vacuum on the bottle the liquid level will rise instead.
we want to pull a slightly negative pressure, just over what would be considered constant during filling.
Option 1: (will work and you can vary the length of the pvc tube so that the float sits at just the right levels)
required : 1 way air release "check valve" in reservoir.
place a piece of PVC tube over the reservoir cap and valve to seal it off from water in tank, then attach this valve (in inverted configuration, so that float closes when empty, and opens when full)http://www.usplastic.com/catalog/item.a ... &catid=569
Seal off by using some pvc pipe and pvc cement.
Problem with this method? the valve body inlet may rest too high from the floor of the tank to allow usage of entire volume of liquid in reservoir.
Option 2: (my preferred method that hopefully will work: haven't tested yet).
Pull a vacuum on the reservoir and fill.
If the pressure level remains constant or negative while filling, you should see the fluid level rise without overflowing the tank.
This option obviously wouldn't require a 1 way check valve to bleed air pressure.
I will test both and return results.