Getting the most performance (natural vacuum) out of gravity lines

[vtwoody]

I have been digging around and seeing some info on the natural vacuum that is possible with gravity lines....anywhere i can look to for specifics?

I am getting a hobby bush started this year and I'm sold on going to vacuum in the future - just don't have the cash (but hoping to generate it this spring :) )

To maximize my efficiency this year (and profit to purchase upgrades next), how do I best capture that natural vacuum?

Some details: have 5-8% slope, majority of trees are sugar, with some red maples. Have potential for 200 taps easy, with room for more expansion in future but not sure of capacity to handle a big volume this year so also looking on input for number of taps I should consider doing this year. Have two 250 gallon poly tanks in metal cages for collection points/transport and I'm working on a 2X4 evap with drop flue back pan (not a sure thing at this point). No RO at this point. Tons of wood available.

My thoughts were to invest in the cv spouts and run all 5/16" line into collection tank, trying to keep it sealed...thinking that end of line going into tank should be near bottom so flow will be going into sap as opposed to entering air space at top and dropping into sap.

How am I doing so far?

Thanks!

[500592]

I would say 100 is plenty unless you have tons of time to boil and cvs are used I vacuum set ups and you need to have sap enter the top not the bottom

[vtwoody]

I would say 100 is plenty unless you have tons of time to boil and cvs are used I vacuum set ups and you need to have sap enter the top not the bottom


I think a bit of your message was lost in typing.....I do plan on CV's. The tanks I have for collection have a big drain valve on the bottom and a screw on lid on top. My plan was to drill a hole in the screw on lid big enough for the end of line and feed line in until it terminated near the bottom of the tank, rather than simply terminating a few inches into tank. Not sure if this would make a difference or not for vacuum.

As to sap volume, worst case scenario is I bring the extra sap to a friend with a larger, established operation but there is no need to go to the effort of setting up twice the capacity for what I can handle....now that is... :)

Thanks for the input!

[vtwoody]

For anyone interested, I did some further research on this forum and around other resources and came up with two separate studies/articles on maximizing natural vacuum:

http://fls.cals.cornell.edu/OCRPDF/FLS-014.pdf

http://www.farmingmagazine.com/article-7484.aspx

The soundbite takeaway I got was:

1) 50 taps better than 25 on 5/16" line. Bigger dia. line would require many more taps to achieve same result. Vacuum produced overcomes inherent friction in smaller dia. line.

2) works best with increased slope, up to 15%. Not so effective on relatively flat terrain (stll some improvement, however) Best if collection point has some elevation drop below taps.

3) System needs to be tight (like any vac system) and, especially in shallow slope locations, no sags, for best performance.

4) No electricity or gas required.....

If your NOT using a vacuum system, makes sense to follow the findings in these studies/articles to maximize the potential production of your gravity system.

Also, Tim Wilmot of the Proctor Maple Research Center, author of the above referenced article, will be speaking on this subject at the VT Maple Conferences in Jan/Feb...

All this may be old news for a lot of folks but thought I would share what I found in my digging as there were a LOT of posts on this subject that contradicted the findings referenced....
:)

[500592]

You don't want the line in the bottom of the tank because the trees at night will suck it up and you could skip the cvs this year then put the adapters on when you get vacuum also strive for five taps on laterals if you plan on going to vacuum soon it will save you a few headaches later on.

[MilesTeg]

I know I haven't posted in a while but for your situation I'd set this bush up for the future vac with utilizing the natural vac. How I would do this would be to run your wire where you plan on having your mainline in the future. I would put 5/16 on this wire instead of the usual bigger line and attach the laterals to that with "T's" or Y's". This in my opinion would do 2 things for you, first it would allow a relatively easy transition over to vacuum next season. Secondly as long as you have a good slope there the natural vac will be created in your 5/16 mainline and possibly in your laterals.

[Bucket Head]

I have a 5/16 line that has 44 taps on it and it almost gets eight inches of vacuum on it when conditions are good. Just for comparisons, the line is about 400 feet long and has a drop of 30 feet from the first tap (highest one) to the collection point.

Steve

[vtwoody]

Lots of great ideas all, thanks