placement of tank and pump vs. elevation

[SapTsunami]

I'm setting up a small-scale 5/16" tubing system around my 1 acre property. I have a ring around the property with about 40 red maple trees. I have a Shurflo 4048 diaphragm pump.I plan to run 5 or 6 home runs, no mainline, just 5/16" laterals.

I want to setup my evaporator and RO concentrator on the back patio, near the house and water/electricity. However this spot is elevated about 6 feet above the low spot of the yard (and about 50 feet away).

Can I put the collection tank next to my evaporator, or do I need to locate it in the lowest spot of the yard? Pentair spec says it can lift a max of 6 feet - will I be losing vacuum pressure this way?

If I put the tank down in the lower spot, I will need to figure out a way to transfer 50' across and 6' up to get to my evaporator.

If I put just the pump down low, could I put a 1/2" transfer hose on the output side of the pump to push the sap up the little hill to the elevated tank?

[SeanD]

Your best bets are to put the collection tank near your evaporator if there's enough slope to get your lines over there OR to use a separate transfer pump to pump from your collection tank in the low spot up to your tank for your RO/evaporator. It's not the best idea to have the Shurflo push all that sap up the hill. You will definitely lose vacuum.

[DRoseum]

You can run 2 pumps in series. I do this for 50 taps on 3 lines of 3/16 that are in front of my house. I use a shurflo to pull the sap and feed directly into an aquatec to push it up a 50 ft hill over about 200 feet long. I use 5/16 tube for the pump line. I get a full 30 inches of vacuum without a problem.

I use an on delay relay to start the aquatec pump first, and then the shurflo. This prevents any pressure build up between pumps on the startup sequence and you can fine tune the delay to overcome the slower thawing of the 5/16 compared to the 3/16th lines.

[VT_K9]

I would give some serious consideration to using a short run of mainline with the 5/16" lateral off of it and limit your taps to 5 per run. This will improve vaccuum transfer and increase the quantity of sap. I would put the collection point at the lowest point and then pump to your processing area. A small electric pump should be fine. Make sure you either run the pump line tight or walk it and drain it to avoid freezing (we used to do this years ago when we had collection points when we used buckets and pumped to the sugarhouse).

Mike

[SapTsunami]

OK, I'm convinced to put my pump at the lowest collection point. I will put the tank at the top of the little 6-foot hill.

6 feet of elevation change at 0.88 inHg per foot is 5.28 inHg. I definitely don't want to lose that much vacuum pressure.

But I'm not sure why the second pump is necessary to push it up over the little hill? The output side of the little Shurflo 4048 is rated to provide 55 psi. Compared to 2.6 psi (needed to overcome the 5.28 inHg elevation gain), that's nothing. Am I missing some phenomenon here?

Also what is the reason for the mainline instead of 5/16" homeruns? Are you thinking it would not be able to drain more taps than that? What's the max flow rate you would assume for a good flow?

[SapTsunami]

I'm trying to understand the recommendation for no more than 5 taps per lateral. It appears to come from here:
https://cpb-us-e1.wpmucdn.com/blogs.cornell.edu/dist/7/5773/files/2016/06/Tubing-Notebook-6th-edition-2fpl9ze.pdf

"Now the common recommendation is for there to be 5-6 taps on a 5/16” line for vacuum to be the
most beneficial. Research at the University of Vermont has shown that the fewer taps
per lateral line the better the yield per tap so that one tap per line gives the highest
yield per tap. However the extra cost and the relatively small increase in yield from
having less that 5 or 6 taps on the lateral line has led to the 5 to 6 tap per lateral line
recommendation."

Well of course "one tap per line would yield the most sap"...take the extreme example where you have a dedicated pump for every single tap.
But if you're already connecting multiple taps to a mainline, how does distributing them amongst many lateral lines confer any advantage?
i.e. if I have 50 taps on one lateral line vs. 10 lateral lines with 5 taps each, going into a mainline. I'm still distributing the vacuum pressure amongst 50 taps, so why is the total any different?
Is it the "crowded subway" analogy? Upstream tap flow blocked by downstream tap flow, so it can't all "fit" in the 5/16" line?
The highest estimate I could find for sap flow under vacuum is 0.4 gallons per hour (https://mapleresearch.org/wp-content/uploads/mnproctor202405cmpssd.pdf)
So 50 taps on one 5/16" lateral at max flow rate would need to carry 20 gallons per hour (or 0.33 GPM). I'm sure that a single 5/16" lateral can carry that much flow, so what's the limiting factor?

[VT_K9]

The research has been done on many topics to support the change in tap count. There is a lot that goes into vacuum. You are not looking at "real" vacuum which would give you the CFM you need to move sap up a rise either under certain conditions or utilizing certain design/builds (lifter/ladder). Shurflos and guzzlers just don't do well.

In 2012 it hit 80 degrees in March and our season was over on gravity flow for 275 taps. Combined with some major leaks in a holding tank it was a bad year. The following year my Dad learned about a sap puller (Guzzler) and we bought one. We bought a Honda EU2000 to run it and caged tank to hold all that sap. We were use to sap "running" with the daylight and freezing at night. We stuck that puller at the end of our largest mainline, made a few other conntections to some lateral mainlines, and fired up the genny. In prior years we averaged 18-25 gallons of syrup on 250-275 taps. The first year on the guzzler hit 35 gallons...quite a change. This was just throwing the guzzler on with no attention to tapping theories or better fittings.

The following year I found Maple Trader and read..read a lot...I changed our taping to 5-7 taps with a max run of 100'. We improved some of the mainlines. We moved away from plumbing fittingg to improve flow. I also followed the discussions about run that guzzler all the time when above freezing. I watched a weather app...up at 0600 hrs and vacuum on. About 1600 hrs I checked sap flow and refueled (and pump sap if needed). This keep the guzzler running. I would run down and check it again at 2200 hrs for the night shift. It the temps were going to drop in a short time I turned it off otherwise more fuel to keep it running. We made 50 gallons of sap...several times the 275 gallon tote over flowed. Maybe 15-30 new taps compared to the year before. Also learned about keeping the lines tight and maybe oversizing to help with ice build up.

The following year we moved to full vacuum and releasers and this year we are going to an electric releaser.

I share all of that because in the readings I saw what others experienced and agreed were the benefits of limiting numbers of taps and length of sap line. I looked at my knowledge of fluid and pressures...too long of a run or too many taps can impede vacuum transfer to the last taps. With that said we currently have 2-3 runs with 120 feet in distance to get to 5 or 6 taps (it was just another 20' to save a solo run of 120' for a single tap). We also have 2-3 runs with 6-8 taps again for the same reason. When a few more trees in those areas mature we will re-run the lines to reduce the tap count per run. I feel the second year on the guzzle gave me the experience I rely on today. We also changed to spinseals for the "saddle". We are finding if we have 1 to 2 taps and not have an unreasonable run distance then it's worth the spinseal. If we used saddles we would push it a little more in distance and try harder to maintain 5-7 taps. Spinseals are $0.89 each and a saddle setup is about $3.50 (last time we bought/compared). We are a smaller operation with about 750 taps (hoping for 1200), but we made the choice to go with any tool/material/product/option to maximize productivity. When we decided to replace a lot of mainlines and had plans to add 400 more taps we added the spinseal to maximize the return on it's cost. We don't regrete it one bit.

Maximize your vacuum (guzzler/shurflo or full vacuum) effectiveness by minimizing low spots (maybe one up size of mainline and proper slope), keep tap count to a reasonable amount, and use fitting which minimize turbelence as the sap flows. Then you'll be asking about an r/o.

Good luck,

Mike

[DrTimPerkins]

As mentioned, the study looking at the number of taps on lateral lines was originally done at UVM PMRC. The result was linear. The more taps on a line, the less sap produced.


Is it the "crowded subway" analogy? Upstream tap flow blocked by downstream tap flow, so it can't all "fit" in the 5/16" line?
The highest estimate I could find for sap flow under vacuum is 0.4 gallons per hour (https://mapleresearch.org/wp-content/uploads/mnproctor202405cmpssd.pdf)
So 50 taps on one 5/16" lateral at max flow rate would need to carry 20 gallons per hour (or 0.33 GPM). I'm sure that a single 5/16" lateral can carry that much flow, so what's the limiting factor?

The citation your reference is for GRAVITY flow, not vacuum flow. Peak sap flow rates under vacuum conditions can be considerably faster (paper in progress now on a follow up paper to this one about characterization of vacuum sap flows ...from studies funded mostly by Chittenden Co. Maple Producers Assn., Vermont).

Regardless, it is not due to the carrying capacity of the tubing. It has more to do with the amount of air in the lateral line tubing system (assuming you have good liquid and air flow in your mainline system). Water is relatively incompressible, so force (vacuum) is transmitted fairly well. Air is highly elastic (shrinks and expands with pressure changes), so air in the system reduces transmission of vacuum (admittedly a poor way of thinking about it physics wise, since we are trying to remove air, not trying to move vacuum???) to the taphole. This problem is heightened by leaks in the system and by warming temperatures, which cause more gas release from trees and bubble growth/expansion throughout the system.

As someone else here said, the best is one tap per lateral. Actually, the best is mainline to each tree with only a short dropline. Second best is dual-lateral lines (top line for air, bottom line for sap). At current syrup bulk prices, neither of those approaches are economically feasible. https://mapleresearch.org/pub/m0216vacuumtubingresearch/ As I like to say, we (PMRC) can do the crazy things so you don't have to....but we often have fun doing it.