Vacuum without a pump?

[Forrest hunters]

I am probably a year from tubing anything but on relatively level ground here. A little slope in some areas. Is it possible to create vacuum with out electric or generators. Here is what I am thinking. Could you modify a carlson surge device and fully enclose it to create a sucking action. See picture below from my old reef keeping days.

Could you take the below design and put it in a 5 gallon bucket with lid closed and this would sit about your collection tank. You would have this above it with a tube running down into it and a one way air valve on top of the bucket. What will happen then is the one way air vale would allow air out of the bucket as it fills and once the sap is above the cap the pressure is released and you have a very strong suction as it empties. This suction would close the one way air valve and create a siphon. This siphon would last until the air is removed from the sap lines and releases the suction.

Another option would be to put a toilet valve inside a bucket and as the level increases the bulb lifts the open and rushed water out creating a siphon and putting suction on the lines.

If these would work how much vacuum could you create.

http://www.reefcentral.com/forums/showpost.php?p=17741865&postcount=714

[Schiefe4]

http://www.uvm.edu/~pmrc/3-16%20Tubing%20-%20Wilmot%20-%20Maple%20News%20Dec%202014a.pdf

http://www.sugarbush.info/forums/tubing-tapping-vacuum-systems/3677-some-notes-tim-wilmots-3-16-beginners-presentation-hyde-park-vmsma-e.html

[DrTimPerkins]

The amount of vacuum you would generate would be proportional to the height of the drop in liquid from the bucket to the tank (within an enclosed tube), or about 0.8" Hg for each 1 ft of drop, which presumably would be fairly minimal. A Carlson Surge Device, as the name implies, is not meant specifically to generate a vacuum, but rather is meant to create surges of water such as those naturally found in reefs. The same holds for using a toilet valve....the vacuum is generated by the drop (height difference), so would probably not be great.

[Forrest hunters]

Dr. Tim,

In a closed system though wouldn't the larger diameter tube emptying the closed bucket quickly create suction on the bucket causing vacuum/suction on the tubing coming into it? I would think the larger tube emptying quickly will put a vacuum on the bucket casing vacuum on the sap lines coming into it. The emptying tube would need to be in the collection tank under the liquid line to give the air lock back pressure to make the emptying device work.

Again to state maybe a different way is that a larger column of liquid leaving will put a suction on the bucket which once the bucket seals again will keep that vacuum on the lines until filled or equalized, then air allowing the one way valve to open and let air leave until emptying again occurs.

Maybe not though. I'm not real good on water dynamics. Just thinking a larger column of water pulling on a smaller one would create more vac.

That's why I love these forums.

[markct]

Your using the surge of water column to pull the vac. I doubt it will have much effect as a foot water column is equal to roughly an inch of vac. So to get even moderate vac would take a signifigant drop of many feet

[DrTimPerkins]

Again to state maybe a different way is that a larger column of liquid leaving will put a suction on the bucket which once the bucket seals again will keep that vacuum on the lines until filled or equalized, then air allowing the one way valve to open and let air leave until emptying again occurs.

YES, it will create a vacuum, but NO, it won't pull much (unless your drop from the bucket to the tank is large). It is the HEAD (difference in height) of the liquid that creates the vacuum, not the volume of liquid. The volume would mean more CFM, but the difference in head is what creates the vacuum.

[Forrest hunters]

Yes. Now I see where my thinking was off. The CFM vs height is where my thinking was off.