Maximum flow per tap

[PCFarms]

I am wondering what your experiences have been with the maximum flow per tap on average for a large installation is. Yesterday, we had a real gusher, like we havn't seen in a few years, I calculated that we were collecting 0.12 Gallons per tap per hour for a good portion of the run. I know that some people recommend sizing equipment to 0.2 Gallons per tap per hour, but I have never seen anything faster than 0.13 in the years where I have had data to actually calculate this (perhaps only 5 years now). The 0.2 figure may give a good safety margin, but on large operations, this could be very costly if that flow rate is never fully realized. I am also wondering if geography makes a big difference, if in certian areas, higher flow rates are possible.

[ecp]

0.2gph per tap sounds like a salesman was trying to sell you equipment. Don't get me wrong it is nice to not have to think about on your largest runs, but the fact is with enough storage your equipment (RO, evap, filter press, ect) can be whatever size you want as long as you can process the sap before it spoils.

[jrgagne99]

I would think the 0.2 gptph pertains mostly to sizing your woods tanks and ability/frequency with which you can haul the sap. Micro-producer (150 taps) here.

[MapleCreekFarm]

My largest flow over 24 hrs was roughly at your figure of .12 gal per tap per hour. However at the peak of flow I'm quite sure the actual flow was higher. Possibly closer to that .2 number.

[DrTimPerkins]

Peak sap flow under vacuum conditions is very dynamic. When the sap first starts to run, flow rates can reach 0.2 gal/hr (or even slightly above), but will drop off fairly quickly, so by about 6 hrs later would be down in the 0.1 gal/hr range and still falling. This is near the beginning of the season when taphole drying (a misnomer...it's actually microbial clogging and tree wound response that result in sap flow reductions from about mid-season onward). Typically a run averaging 1 gal in 24 hrs is OK, 2 gal in 24 hrs is a good run, anything above that is terrific (this is for "woods" trees...big lawn or roadside trees can have huge flows).

We can go back to the "pipe" model to understand sap flow in maple trees. If you have a hollow pipe stuck in the ground filled with water, and poke a small hole in it near the bottom, water will run out quite fast at first because there is a great deal of head pressure. As the water level falls, the pressure drops and the flow rate will drop as well.

For more info, see https://mapleresearch.org/wp-content/uploads/SapVac.pdf especially pages 23-25.

[Ultimatetreehugger]

As of today I used my releaser dump cycle to calculate approximately what my flow is. On one woods I was flowing at 408 gph about .18 per tap per hour on a piece with ~2300 and my releaser dumped 52 times in the period of an hour. It was running this hard for about 2 hours.

https://youtu.be/YfffeyFPoCA

[Chasefamily]

I have been having problems with one of my pumphouses this year. Late yesterday i got running again pulling great vacuum. Also this woods has by far the freshest tap holes i have. pulled in an avg of .16 gals per tap per hour as of 6 this morning.

[wiam]

I’m pumping approximately 1600 feet underground with my electric releaser. Before I buried wire to this releaser I wanted to make sure it would work. 2 years ago I took water up and hooked up the releaser under vacuum run by generator. I put I flow meter on the line feeding water. Tiny bit over 7 gpm kept releaser even. I had about 940 taps on the bush. Buried the wire and ran this system. I use my old single vertical mechanical for a moisture trap up there to keep sap out of my buried vac line. The pump did not keep up twice when lines were thawing and I believe the mechanical dumped twice all season. I was happy with that. Mechanical has not dumped this season.

[DrTimPerkins]

When the sap first starts to run, flow rates can reach 0.2 gal/hr (or even slightly above), but will drop off fairly quickly, so by about 6 hrs later would be down in the 0.1 gal/hr range and still falling.

I should have noted that sap flow patterns mimic stem pressure patterns in the tree. Upon thawing, pressure shoots upward, then slowly drops over time.

[TapTapTap]

I’m pumping approximately 1600 feet underground with my electric releaser......

William,
How did you do the underground piping to address the potential for freezing? Specifically:

- How did you treat the section that enters/exits the ground? Or are you underground at those locations too?
- How do you maintain a downward pitch without curling of the line that would create waves? those waves would create sags that could trap sap that might freeze throughout the run. Even without a sag, a trickle flow could freeze up a line.

I've thought about this a lot and I finally used a 4" sleeve to install a 80 ft underground run.

Ken