Maple Syrup Tree tap new vacuum method questions
Maple Syrup Tree tap new vacuum method questions
(OP)
I posted this a few days ago in mechanical forum but got my hand slapped and thread erased for being a "hobby." I suppose it is, although maple syrup production in America and Canada is BIG business. The most I have ever collected and cooked down is about 500 gallons in a season, so perhaps for me it is a hobby. Anyway...
For 20 yrs this Ele Engineer has used old fashion buckets on trees when collecting sap to make syrup. But there is a new kid in town! 3/16 plastic feeder line to go tree to tree and end in ONE BIG bucket at the bottom of the hill! No vacuum pumps required. The small diameter creates a vacuum based on the height of the "last tap" on the line vs. the discharge end. Vacuum also sucks the sap out 3-5x more than just old bucket gravity feed! So time is here to give it a try next spring. Here is my dilemma: What is the vacuum on each tree drop? 1975 was a long time ago for this kind of mechanical engineering problem, and I am having a hard time reconciling the facts PHD professors at the universities in New England are giving. So I am out of my motor groups and over here for advice!
Here are the facts as the PHD profs give:
The amount of vacuum at any one particular tree is dictated by the amount of drop from that particular tap to wherever the sap exits the 3/16” system (either into a mainline that is not under vacuum or into a tank). Each foot of standing sap in a 3/16” line theoretically generates the equivalent of 0.88” Hg vacuum. However given that there are also air bubbles in the line, and friction in the line, the actual amount of vacuum is more typically around 0.8” Hg per foot of drop.
Therefore a tree with a tap that is 10’ above where the sap exits the 3/16” line would yield 8” Hg (assuming the system is leak-free). A tree that is 10’ higher than that on the same line would have 16” Hg, a tree 10’ above that one would have 24” Hg, and a tree 10’ above that would have 27-28” Hg (given that the maximum is 29.92” Hg at sea level under standard barometric conditions).
This all assumes there is some slope on the line at the bottom, and that there is not a long section of 3/16” line on level ground where frictional forces start to increase backpressure in the system and reduce the functional vacuum upstream.
Thus, in the example above, the trees that are highest on the slope will experience the highest vacuum level, whereas those at the bottom will experience the lowest. If you had a 35’ drop AFTER the lowest tree (35’ x 0.8” Hg/ft = 28” Hg), then ALL the trees on that line would experience the highest level of vacuum.
So say I have this 400' long 3/16 tubing line. Say the end tap is 35 foot above the lower drain end, and no taps along the way. The vacuum should be 27" Hg anywhere along this whole 400' line, right? I am told to put a vacuum gauge at this end tap and I can read the vacuum. What no one says is: what if I put a tap 10' in from the open drain end? Will it STILL read 27" Hg?
Next, let me now add a tap at 200' or middle of the run, and it is 1/2 as high - 35/2=17.5' above the low discharge end. According to the professors, this tap will have a vacuum of 1/2 or 13.5" Hg... but but but... If my first tap made 27" Hg vacuum all along the 400' line, how do I reconcile this 13.5" Hg?? Is it only 13.5" Hg from the actual tree tap down 2 foot to the main 400' line T with 27" Hg in it? What happens when the different two vacuums meet?
Seems to me the 400' feeder line may NOT have 27" Hg all the way? Maybe it STARTS at 27" Hg at the 35' height at the end, and it drops linearly with reduced height until it is 0" HG at the open other end (collection point)? This would seem to satisfy different vacuums along the way... Is this statement the answer?
At the end of the day, we will have 20-25 "T" fittings, each going off to a tree tap, tapping into that 400' line to feed into the final single collection barrel.
Please help me understand how the vacuum is distributed along this line.
Thanks from a sparky!
For 20 yrs this Ele Engineer has used old fashion buckets on trees when collecting sap to make syrup. But there is a new kid in town! 3/16 plastic feeder line to go tree to tree and end in ONE BIG bucket at the bottom of the hill! No vacuum pumps required. The small diameter creates a vacuum based on the height of the "last tap" on the line vs. the discharge end. Vacuum also sucks the sap out 3-5x more than just old bucket gravity feed! So time is here to give it a try next spring. Here is my dilemma: What is the vacuum on each tree drop? 1975 was a long time ago for this kind of mechanical engineering problem, and I am having a hard time reconciling the facts PHD professors at the universities in New England are giving. So I am out of my motor groups and over here for advice!
Here are the facts as the PHD profs give:
The amount of vacuum at any one particular tree is dictated by the amount of drop from that particular tap to wherever the sap exits the 3/16” system (either into a mainline that is not under vacuum or into a tank). Each foot of standing sap in a 3/16” line theoretically generates the equivalent of 0.88” Hg vacuum. However given that there are also air bubbles in the line, and friction in the line, the actual amount of vacuum is more typically around 0.8” Hg per foot of drop.
Therefore a tree with a tap that is 10’ above where the sap exits the 3/16” line would yield 8” Hg (assuming the system is leak-free). A tree that is 10’ higher than that on the same line would have 16” Hg, a tree 10’ above that one would have 24” Hg, and a tree 10’ above that would have 27-28” Hg (given that the maximum is 29.92” Hg at sea level under standard barometric conditions).
This all assumes there is some slope on the line at the bottom, and that there is not a long section of 3/16” line on level ground where frictional forces start to increase backpressure in the system and reduce the functional vacuum upstream.
Thus, in the example above, the trees that are highest on the slope will experience the highest vacuum level, whereas those at the bottom will experience the lowest. If you had a 35’ drop AFTER the lowest tree (35’ x 0.8” Hg/ft = 28” Hg), then ALL the trees on that line would experience the highest level of vacuum.
So say I have this 400' long 3/16 tubing line. Say the end tap is 35 foot above the lower drain end, and no taps along the way. The vacuum should be 27" Hg anywhere along this whole 400' line, right? I am told to put a vacuum gauge at this end tap and I can read the vacuum. What no one says is: what if I put a tap 10' in from the open drain end? Will it STILL read 27" Hg?
Next, let me now add a tap at 200' or middle of the run, and it is 1/2 as high - 35/2=17.5' above the low discharge end. According to the professors, this tap will have a vacuum of 1/2 or 13.5" Hg... but but but... If my first tap made 27" Hg vacuum all along the 400' line, how do I reconcile this 13.5" Hg?? Is it only 13.5" Hg from the actual tree tap down 2 foot to the main 400' line T with 27" Hg in it? What happens when the different two vacuums meet?
Seems to me the 400' feeder line may NOT have 27" Hg all the way? Maybe it STARTS at 27" Hg at the 35' height at the end, and it drops linearly with reduced height until it is 0" HG at the open other end (collection point)? This would seem to satisfy different vacuums along the way... Is this statement the answer?
At the end of the day, we will have 20-25 "T" fittings, each going off to a tree tap, tapping into that 400' line to feed into the final single collection barrel.
Please help me understand how the vacuum is distributed along this line.
Thanks from a sparky!





RE: Maple Syrup Tree tap new vacuum method questions
Note that all your taps need to be well sealed. Any that let air in will destroy the vacuum.
A.
RE: Maple Syrup Tree tap new vacuum method questions
It should be easy to put a temporary vacuum gage tap in if you use push-in fittings.
Put the tap next to the tree.
You won't get 27inHg all along the tube, as zeusfaber explained.
I noticed the revolution in collection a couple of years ago, just driving by.
I could swear that there was one collection line per tree, with no tees.
All the tubing loosely bundled with ty-raps or similar.
A hundred feet of polypropylene tubing is probably much cheaper than a stainless steel tee fitting anyway. I wouldn't trust plastic tee fittings in cold weather.
Mike Halloran
Pembroke Pines, FL, USA
RE: Maple Syrup Tree tap new vacuum method questions
Some may morn the loss of old traditional methods. I find it a little sad to see the old ways going.
BUT I doubt that the collectors of maple syrup miss the old slow ways at all.
Neglecting friction losses, The vacuum will be directly proportional to the difference in elevation.
Another way to look at it is to look at the pressure at the bottom if you close the line.
If you close the line at the bottom with a pressure gauge, the gauge pressure at the bottom in in-Hg will equal the vacuum in in-Hg at the top when the bottom is opened.
Now subtract some for air bubbles and friction.
Apply basic siphon principles.
The air bubbles will be somewhat compressed in the shut in test and somewhat expanded under vacuum. Some difference but not as much as you may think.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Maple Syrup Tree tap new vacuum method questions
For years we DID use 5/16 tubing - with it, it WAS one per tree since its larger size did not cause the self vacuum of the smaller diam new stuff. I say new but it was "invented" a year or so ago, just has taken a while to take off; buying 3/16 products is still hard to find as it still has not taken off across the board. The studies show upto 25 or so T taps does not reduce effectiveness of the vacuum suck. And no priming needing as when the tap drilled into the tree, sap usually immidiate.y begins pouring our - so I think as long as SOME gets into the tubing, gravity and siphon will take over and drop it down causing the vacuum.
I've been using combination of ss drip taps and plastic ones for years now; I much prefer the 30 cent plastic over the $2.00 ss ones; plus they seal much better into the tree. And after years of hitting them with hammer to embed in the tree has not left me with a broken one yet. And now the 3/16 size ones aare 19 cents for single use ones or 23 cents for the same old solid plastic ones.
A surprise I found is the evidence shows a SINGLE barb for the push on tubing is less likely to leak than the original two barbs used...
Thank you for the pressure gauge at bottom vs vacuum gauge at the top; that totally completes my understanding of it now! Just like a barometer! Now I can't wait until next year to try this! Will spend time this summer mapping out my tree tubing route(s) and marking each tree then marking the tubing Ts so when taken down next spring I can quicklly put up again the following year. I will NOT miss the 45 minutes it takes today to go tree to tree to empty buckets! I bought a few $2 vacuum gauges so I plan to T the end of the run with a gauge I leave on so I can make sure no leaks thru the 2-3week season.
Thanks again all for the great info!
www.KilroyWasHere<dot>com
RE: Maple Syrup Tree tap new vacuum method questions
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Maple Syrup Tree tap new vacuum method questions
I think he meant 500 gals of sap. @ about 40:1 ratio, that yields about 12.5 gals of syrup. (Yum!). (Or did you really mean 500 gals of syrup OP?)
gbangs
TC 8.3.3
NX 8.5.3.3 MP11
RE: Maple Syrup Tree tap new vacuum method questions
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Maple Syrup Tree tap new vacuum method questions
https://www.bloomberg.com/news/articles/2013-01-02...
RE: Maple Syrup Tree tap new vacuum method questions
Interesting story, Ham...
gbangs
TC 8.3.3
NX 8.5.3.3 MP11
RE: Maple Syrup Tree tap new vacuum method questions
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Maple Syrup Tree tap new vacuum method questions
www.KilroyWasHere<dot>com
RE: Maple Syrup Tree tap new vacuum method questions
a) stressing the tree, maybe not in a normal year but what about dry or hot years?
b) reducing either the sugar content or the "maple" flavor.
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: Maple Syrup Tree tap new vacuum method questions
Anyway, my understanding from the Vrmont and NH wizards that even this higher tap volume does NOT hurt the trees at all. In 20 yrs of tapping, I have had NO maples die... Fingers crossed...
www.KilroyWasHere<dot>com
RE: Maple Syrup Tree tap new vacuum method questions
Keith Cress
kcress - http://www.flaminsystems.com
RE: Maple Syrup Tree tap new vacuum method questions
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Maple Syrup Tree tap new vacuum method questions
so buckets vs 3/6 line at 30' drop (30" Hg) = 8% x 30= 240% or 2.4x increase...
from: https://www.themaplenews.com/story/results-in-from...”-tubing-research/81/
4-5x more per tap, not just faster
from: http://mapletrader.com/community/showthread.php?20...
and
http://www.nysmaple.com/files/The%20Pipeline/Pipel...
www.KilroyWasHere<dot>com
RE: Maple Syrup Tree tap new vacuum method questions
www.KilroyWasHere<dot>com
RE: Maple Syrup Tree tap new vacuum method questions
Did you plow all those trees down? I guess the wood is sought after for fine furniture.
My buddy on the next street over plowed his 800 sqft house and built a 2,900sqft behemoth on the same lot. There was a Black Walnut just out his back door of the small place we had to take down. We limbed it and stuck the ~30in diameter seven foot stump in my pickup. I called around to see if it could be sawed. Sure enough some guy had a portable sawmill out on a site in the nearby hills. I drove out and found it was a bandsaw. Really pretty cool as it was fairly quiet and automated and the kerf was tiny. We threw the trunk on it and he sawed it into about twenty planks with the bark still on the edges and told me to stack them with gaps in a cool dark place for a year or more.
I stacked them at my place of work in the disused basement of a Silicon Valley engineering firm. LOL They stayed there for 7 years. I'd put four paint stirrers between each of them. When I left the company I took it all with me to haunt me at my new office. I finally realized I was not going to build a massive dining table out of them and put them on Craigs List.
I was flooded (shocked really) by interest. I sold it all to a slavering furniture maker who wanted it to make medieval style heavy chairs. Peeled $450 out of his wallet and that was about 2005.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Maple Syrup Tree tap new vacuum method questions
Dan - Owner
http://www.Hi-TecDesigns.com