Very Simple Sap Lines

[backyardsugarer]

Hello everyone,

I have a quick question. I am looking at running 5 or 6 small sap lines into 30gallon barrels. The distance would only be about 25 yards and I would look to run about 20 taps per line. Does it have to be vented and can I use regular tubing or do I have to put in thicker lines as main line? Also, How much of an angle must it run down hill?

I plan to then pump the sap to my sugar shack using my new pump. It should cut down on some leg work.

Thanks.

Chris

[Brian]

I would not vent it because it will make some natural vacuum as the sap runs down the hill. If possible, ten taps per 100 feet of 5/16 tubing is the general rule of thumb. Some say 20 taps works good on up to 150 feet of tubing, you should maintain a 3 to 5 percent grade on your lines, but more is better, I believe. You shouldn't need any main line at all. keep the tubing tight and let the sap flow!!

Brian

[themapleking]

I did the same thing last year. You don't need main line for that. 5% grade or more is good don't vent the lines. Keep the taps a little less if you can. I had to 30 gal cans set up with about 25-30 taps running in each. The lines were less than 100 ft. Just drill a 5/16 hole in the lid for the lines to go in.

[powerdub]

I would not put any more than ten taps per line. 5% grade or more is good. I prefer rigid myself as it cleans better. DO NOT VENT. Unless you want to see your sap run uphill and out on the ground.

[WESTVIRGINIAMAPLER]

Chris,

I put as many as 25 taps on a lateral line and have always had good success. I am not saying that is the best way, but it has always worked good for me.

I am sure I will get bashed for this information, but everyone has different ways of doing things and this has worked good for me.

Brandon

[powerdub]

I don't want to bash either but I know by experience when I broke those 20 tap runs in half they ran better. Try it with a run or two. I would be interested in the results.

[Swingpure]

I did the same thing last year. You don't need main line for that. 5% grade or more is good don't vent the lines. Keep the taps a little less if you can. I had to 30 gal cans set up with about 25-30 taps running in each. The lines were less than 100 ft. Just drill a 5/16 hole in the lid for the lines to go in.

I am just now considering running some lines, if you do not have a main line, do you have individual lines from each tap that run to the barrel, or do you connect them with T connectors?

Thanks

[DrTimPerkins]

I am just now considering running some lines, if you do not have a main line, do you have individual lines from each tap that run to the barrel, or do you connect them with T connectors?

If you're just using gravity flow (not pumped vacuum), then you can have up to about 20 trees on each lateral line (5/16"), although no more than 10 might do a little better. You want to have single trunk-lines (lateral line) for each run of trees, with each individual tree connected via a tee and drop-line. DO NOT split/connect the lines with wyes and DO NOT vent the lines. Lines should run downhill, be tight (no sags) and relatively straight (zig-zagging from tree to tree is OK if it is not too excessive and the lines run continuously downhill).

[Sugar Bear]

The key to getting good flow using 5/16" runs is having a straight final run of tubing from your lowest tap to the collection barrel of 75 feet or more and a drop of 5 vertical feet per 25 feet of run.

You want no fittings of any kind mucking up a final run.

Less then this will still work but more then this will work better and support more taps and more fluvial taps.

So if it is a 75 foot final run then it should drop 15 vertical feet. These numbers have provided up to 17 inches of mercury for me with 7 taps.

More and/or longer pitch then that would get you more inches of mercury and support more taps on the run.

The pitch of your tubing run above the lowest tap is not as critical as your final run as described above.

But tubing in the "taps" area should be straight and pitched downward as well as possible. But pitch in this area is not required however it will prevent back flow into the tap holes at sap flow shut down time, if that sap is not drawn out at shut down time when the sap column in the "final run" collapses, as it will be in a entirely pitched run. Sap that collects in any Non pitch area will act as a counter weight against the column of sap in the final run, reducing its efficiency and effectiveness of suction at tap hole location.

The natural vacuum is generated by the sap column that collects and holds in the "final run" of tubing. It is the vacuum engine. It is the CRUX behind the formulation of natural vacuum.

This final run is critical in making your tubing runs more or at least as efficient as if the taps were each on individual drops to buckets. If you don't have or can not have these "final runs" set up properly you will be more efficient with drops to buckets.

3/16" tubing will more effectively set up these final run columns on less pitch but are laced with other pit falls.

If you want or can generate natural vacuum in the run and be as or more efficient as taps on drops to buckets, venting of any kind in your run is prohibited.

If your system is "swamped/sap locked" at tap hole locations and the run does not have enough slope to generate any effective level of output flow on the encased column of sap and thereby only creates enough vacuum to keep sap "stuck" in your lines , I suggest venting at the beginning/top of the run. This way you will run closer to the efficiently as taps on drops to buckets and really not expose tap holes to any more air then taps on drops to buckets would expose them to. So you may as well be vented in this scenario.

If the slope in your run is very small, your sap may back flow at the vent. If that happens take down the lines and put buckets up.

More then anything else taping maple trees is like poker. Got to know when to hold em and know when to fold em. And make the best of what you are dealt.

You can't make a Royal Flush out of a 2, 4, 7, 9 and jack of any kind.

[Swingpure]

The natural vacuum is generated by the sap column that collects and holds in the "final run" of tubing. It is the vacuum engine. It is the CRUX behind the formulation of natural vacuum.
.

Hmmm, I thought I finally had what I was going to do firmly in my head and that I could sleep at night.

So if I have a run of 8 trees, let’s say over a downhill distance of 150’, I should further extend the tubing 75+ feet downhill to create the final run and the vacuum? I have three trees about 125’ down from the last of the 8 tree run. Would I run the 3/16” tubing to a collection barrel down by the three trees, but not connect up to the three trees. And just have the three trees separately connect to the collection barrel?

Gary

[DRoseum]

Why not put all 11 trees on a single run and tank just below the last one?

Also - reiterating... do not vent at the top of the run. That defeats the natural vacuum that is being put on the tap holes.

[Swingpure]

Why not put all 11 trees on a single run and tank just below the last one?

Also - reiterating... do not vent at the top of the run. That defeats the natural vacuum that is being put on the tap holes.

I may have misunderstood, when Sugarbear said:” You want no fittings of any kind mucking up a final run.” I was afraid of putting three fittings after the long 125’ “final” run.

[Sugar Bear]

Hmmm, I thought I finally had what I was going to do firmly in my head and that I could sleep at night.

So if I have a run of 8 trees, let’s say over a downhill distance of 150’, I should further extend the tubing 75+ feet downhill to create the final run and the vacuum? I have three trees about 125’ down from the last of the 8 tree run. Would I run the 3/16” tubing to a collection barrel down by the three trees, but not connect up to the three trees. And just have the three trees separately connect to the collection barrel?

Gary

I can't speak for 3/16 tubing and the hydro dynamics are definitely going to be different then 5/16". But If you were to use 5/16" tubing I would definitely do it this way. Unless you can pick up the three taps and go another 75' of tubing that drops 15' minimum from the last of those three low taps.

I have had a run almost identical to this with three taps at the bottom of the final run, T'd into the final run, just before the collection barrel.

Separated them mid season. Very significant improvement in flow rates.

A column of sap generating vacuum should be as straight and as long and as uninterrupted as possible.

The more taps the steeper the sap column can and or needs to be and the more inches of mercury it will generate.

1) Too few taps and too steep a a final run will not generate a sap column because it will run out too quickly and not build up in the lines. The flow rate in this scenario will be about the same as if you had all your taps on drops to individual buckets.

2) Too many taps and not steep enough of a final run will saturate and sap lock your tubing with sap. The sap won't run out fast enough because friction of the liquid in the tubing overrides the limited amount of gravity acting upon it. In addition a limited amount of vacuum generated in the system has negative effects on sap flowing out the tubing as well. These forces combined make for a run that is less efficient flow wise then taps on drops to buckets. ( you would be better off venting the tubing in this case at the top as it will bring you closer to a taps on drops to buckets flow rate )

Somewhere in the middle of 1 and 2 is a tightly sealed natural vacuum system that functions above taps on buckets. The only way to get a feel for this spot is through trial and error.

Vacuum gauges at the top of experimental runs are a MUST if you want to get a grasp on what works and what does not.

It is also important to be able to visually detect/feel tubing that is loaded with sap and tubing that is empty. I do this by putting a dip in my tubing with my hand, if the dip fills with sap the tubing at that location is still empty. If it does not fill it is because it is already filled and part of the existing sap column. I am always able to determine the exact length of my sap column by doing this.

[Swingpure]

1) Too few taps and too steep a a final run will not generate a sap column because it will run out too quickly and not build up in the lines. The flow rate in this scenario will be about the same as if you had all your taps on drops to individual buckets.
.

The best I can do is have 8 taps on a good steep grade, then have a long uninterrupted 125’ steep run to a collection barrel. I have two situations like that. I also have three five tree short runs.

Is the fact that I only have a maximum of 8 taps, negate any chance of vacumn gains, even with the long final runs?

[Sugar Bear]

The best I can do is have 8 taps on a good steep grade, then have a long uninterrupted 125’ steep run to a collection barrel. I have two situations like that. I also have three five tree short runs.

Is the fact that I only have a maximum of 8 taps, negate any chance of vacumn gains, even with the long final runs?

I have a run with 7 taps and a final run of about 80 feet and it vertically drops around 15 to 18 feet to the collection barrel from the lowest tap.

Last year I put a vacuum gauge at the highest tap.

During the beginning of the season when sap flow was slow I pulled about 10 inches of mercury ( a unit measure of suction ) on the gauge. I had about a 35 foot long column of sap in the final run of 5/16" tubing. ( mid afternoon ) That column ended where it was dripping out the tubing into the collection barrel and ended 25 feet up the tubing.

A couple weeks later, at peak of the seasons sap flow, I was able to measure a column of sap that was 75 feet long and gave me 17 inches of mercury at the gauge. Even more suction. My column of sap was almost up to the first taps. Just a few feet short of it. If I had a tap or two more my sap column would have been past it and it that situation my intuition tells me that I would have had too many taps on my run for that moment in time.

I would say if your sap column runs into your drops coming into your mainline ( in this case 5/16" tubing ) from taps, you have too many taps on your line. I don't think you want to sap swamp a tap hole in a vacuum situation. Although I am not certain of the drawbacks of that.

Too many taps at one point in the season may be too few at another point in the season for a specific run of tubing. It is dependent on how well the sap is flowing and how well the trees that you have tapped perform.

I will say that the 7 taps I have on my mentioned rig are saptual dynamoes.


In your case the 125' may be perfect. I would go with it. Put a gauge on the top. Make sure its tight. And look for that column of sap in the final run. If its there you will have inches of mercury on the gauge. Assuming you have no air leaks in your lines.

Sap column/suction will keep sap running longer into the freeze of evening however will eventually collapse and go away when sap stops flowing at taps. Collapsing column should pull all sap out of the run because of the hydro dynamics involved with "moving" sap, unless you have pronounced sags in the run.

As that say out on the river. Tight lines

[DrTimPerkins]

2) ...you would be better off venting the tubing in this case at the top as it will bring you closer to a taps on drops to buckets flow rate )

There is almost never a good reason to vent maple tubing. 1) You will lose any natural vacuum that might develop. 2) Venting pulls in air which contain microbes, which leads to faster taphole drying. Venting has been shown repeatedly to result in lower sap yields. The key is to have a slight amount of slope. Some liquid retained in the tubing when the run stops is normal in most cases.

[DRoseum]

Dr. Tim can weigh in, but I dont think adding the bottom 3 taps would have a negative effect on the upper 8. If anything it's more sap in the line and a slightly longer run, which would increase vacuum on those upper 8. Vacuum is generally proportional to drop/slope. My recommendation is put all 11 on a single line with your final tank as low as practical after your final tap.

[Sugar Bear]

There is almost never a good reason to vent maple tubing. 1) You will lose any natural vacuum that might develop. 2) Venting pulls in air which contain microbes, which leads to faster taphole drying. Venting has been shown repeatedly to result in lower sap yields. The key is to have a slight amount of slope. Some liquid retained in the tubing when the run stops is normal in most cases.

"almost never" denotes an exception. Could you describe that exception and what the circumstances would be for it?

[Swingpure]

I read a lot of articles and they all said to have a long, steep run after the last tap, as Sugar Bear had said. I am going to buy more tubing on Wednesday and I am rethinking how I will set up my lines.

I will also buy the single handed 3/16” tool at CDL. I did check out the tool at Mapletech tools and they did reply to me about shipping costs, but by the time it came across the border and the exchange, it was not any cheaper than CDL.

I still wonder about setting the lines up at the beginning of November before the snow flies, especially if some people leave them up all year round. We do have squirrels and chipmunks, but they are not overly active after November.

[DrTimPerkins]

Dr. Tim can weigh in, but I dont think adding the bottom 3 taps would have a negative effect on the upper 8. If anything it's more sap in the line and a slightly longer run, which would increase vacuum on those upper 8. Vacuum is generally proportional to drop/slope. My recommendation is put all 11 on a single line with your final tank as low as practical after your final tap.

Correct. As long as the bottom taps don't overload the lines, or as long as you don't have to cross a long flat stretch of ground, it would be fine to add them. They will not get any/much of any benefit of natural vacuum if there is little drop beyond them to the point of sap exit from the line, but it won't hurt either.

[DrTimPerkins]

I read a lot of articles and they all said to have a long, steep run after the last tap...

That is the optimal configuration, but not always possible in some settings.

[DrTimPerkins]

"almost never" denotes an exception. Could you describe that exception and what the circumstances would be for it?

When you're cleaning/draining lateral/drop lines at the end of the season and wish to evacuate all the liquid from them.

[Sugar Bear]

I read a lot of articles and they all said to have a long, steep run after the last tap, as Sugar Bear had said. I am going to buy more tubing on Wednesday and I am rethinking how I will set up my lines.

I will also buy the single handed 3/16” tool at CDL. I did check out the tool at Mapletech tools and they did reply to me about shipping costs, but by the time it came across the border and the exchange, it was not any cheaper than CDL.

I still wonder about setting the lines up at the beginning of November before the snow flies, especially if some people leave them up all year round. We do have squirrels and chipmunks, but they are not overly active after November.

6 years ago when I started with gravity tubing I don't know what I would have done. And even with this great website I would have done the wrong thing.

But for today and as for myself and I was you .....

If you have good slope in your grove and you have sugar maples in your grove I would use 5/16" tubing. Run straight as possible down the slope with 7 to 10 taps or so each. Avoid zig zags by using multiple separate lines parallel to each other. Final runs as straight as possible of uninterrupted tubing (Fairly CRITICAL) on each run should be at least 75 feet long and drop at least 15 to 18 feet in that 75 feet ( CRITICAL). You can angle 2 lines into one collection barrel. My experience is that two of these such lines with 7 taps each going into one 55 gallon barrel will overflow that barrel in short order when the trees are dealing. But you can do more if your tank is bigger then 55 gallons.

All runs must be sealed tightly. No leaks. Try a gauge or two for your peace of mind. If no sap column builds you might have a bad leak. If it is not a big column you might have a slow leak. If you are around 15 to 20 inches of mercury or more you a functioning as designed. This assumes prime time and the trees are dealing. At trickle time a functioning as designed system just may not function nearly as well. Perhaps only 5 to 8 inches of mercury. Be patient, nature delivers a Royal Flush only on its terms.

The length of your sap column is formed by two forces.

The number of taps on the run and the pitch of the final run.

Given the same number of taps on a run. The steeper the pitch of the final run the shorter that sap column will be because more gravity is acting on it because it is steeper. But it will actually generate a bit more vacuum as a longer sap column on a less steep pitch. But the differential increases as the slope diminishes. If your sap column is 10 times as long with a final run on level ground. Well guess what? No nothing. Taps with back pressure. Ouch! vent the system. Do something else. Take down the lines. Put up buckets. Call God!

Its all baby physics.

1) Be ready to boil.
2) Consider a home built RO.

Otherwise be prepared to be very frustrated with your taps on tubing unless you have a pump.

[Biz]

Sugar Bear, are you saying you can get 15-20" of natural vacuum using well set up 5/16" lines? 3/16" lines will get you good natural vacuum with some drop but 5/16" lines cannot develop as much vacuum. Curious how this works. I use all 3/16" lines and get good vacuum and sap production out of my gravity 3/16" lines. Even better for lines with the pumps.

Dave

[Sugar Bear]

Sugar Bear, are you saying you can get 15-20" of natural vacuum using well set up 5/16" lines? 3/16" lines will get you good natural vacuum with some drop but 5/16" lines cannot develop as much vacuum. Curious how this works. I use all 3/16" lines and get good vacuum and sap production out of my gravity 3/16" lines. Even better for lines with the pumps.

Dave

I got 17 inches last year on a 5/16" run which had 7 sugar maple taps ( albeit frisky taps) . Had decent slope throughout. Not a cliff but decent slope. I want to say about 5 pitch ( 25 feet out and 5 feet down ) at the sap column location.

I have not used 3/16" and have been told and read that it generates vacuum through a broader range of geography then 5/16" but has clogging problems and sanitation problems much more readily then 5/16".

Even so I plan to set up a 3/16 gravity run this coming season. On Red Maples.

[Sugar Bear]

Correct. As long as the bottom taps don't overload the lines, or as long as you don't have to cross a long flat stretch of ground, it would be fine to add them. They will not get any/much of any benefit of natural vacuum if there is little drop beyond them to the point of sap exit from the line, but it won't hurt either.

Tim

If the sap column formed from the higher taps rises above the three lower taps. Which in my case it did and in most cases I suspect would, won't that create back pressure into the three lower tap holes ( reverse vacuum ). I mean the sap in the column then want's to go to 4 places. Those 4 places being the collection barrel, and into the three lower tap holes that are "on column" thus cutting down the flow rate of the three lower tap holes.

It seems to me that a sap column should never reach or encroach on a tap drop.

Let me know where I am confused please.

Rob

[Biz]

Interesting, perhaps you have an ideal setup for the good vacuum. I do not have clogging problems on my 3/16 lines but had an issue with sanitation once, the next year after I decided not to bother cleaning the lines. Now the lines get cleaned every year, and I try to do drop replacement every 2 years, line replacement every 4 years or when I see too many moldy spots.

Dave

[Sugar Bear]

Interesting, perhaps you have an ideal setup for the good vacuum. I do not have clogging problems on my 3/16 lines but had an issue with sanitation once, the next year after I decided not to bother cleaning the lines. Now the lines get cleaned every year, and I try to do drop replacement every 2 years, line replacement every 4 years or when I see too many moldy spots.

Dave

My setup is not ideal but decent and suspect that I could get a fair amount more then 17". I started out last season ( after I fixed the leak at the gauge connect ) getting around 6 to 8" and then went to around 13" and peak run gave me 17". What are you able to get on 3/16??

[DrTimPerkins]

Sugar Bear, are you saying you can get 15-20" of natural vacuum using well set up 5/16" lines? 3/16" lines will get you good natural vacuum with some drop but 5/16" lines cannot develop as much vacuum. Curious how this works.

5/16" tubing will develop natural vacuum if installed properly. This has been known for some time. https://ecommons.cornell.edu/bitstream/handle/1813/4046/FLS-014.pdf?sequence=1&isAllowed=y It is more difficult in some ways, requires more taps per lateral line, is less consistent, and the vacuum will "collapse" at certain times and not persist well during low or no flow periods, but it certainly can be done.

3/16" tubing will develop natural vacuum much faster and will retain it far longer during a flow. This is because the internal diameter of 3/16" tubing is small enough that a column can develop (due to cohesion of water) and be held within the tubing. That's not the case with 5/16" tubing, in which the water (sap) column will naturally drain unless maintained by continuous flow of sap.

The biggest advantage with 5/16" natural vacuum systems over 3/16" is that there is less clogging.

[DrTimPerkins]

If the sap column formed from the higher taps rises above the three lower taps. Which in my case it did and in most cases I suspect would, won't that create back pressure into the three lower tap holes ( reverse vacuum ).

I am not entirely sure what you mean. If the sap column rises higher in the lateral line than the lower taps (which should only happen if the drain end gets blocked, the tubing at the end with the lower taps is on flat ground or below the lateral line at that elevation, there is a clog or blockage in the line restricting flow, or the line is seriously overloaded with taps), then the problem is with the installation somewhere.

[berkshires]

5/16" tubing will develop natural vacuum if installed properly. This has been known for some time. https://ecommons.cornell.edu/bitstream/handle/1813/4046/FLS-014.pdf?sequence=1&isAllowed=y It is more difficult in some ways, requires more taps per lateral line, is less consistent, and the vacuum will "collapse" at certain times and not persist well during low or no flow periods, but it certainly can be done.

3/16" tubing will develop natural vacuum much faster and will retain it far longer during a flow. This is because the internal diameter of 3/16" tubing is small enough that a column can develop (due to cohesion of water) and be held within the tubing. That's not the case with 5/16" tubing, in which the water (sap) column will naturally drain unless maintained by continuous flow of sap.

The biggest advantage with 5/16" natural vacuum systems over 3/16" is that there is less clogging.

Seems to me the best of all possible worlds would be 5/16 lateral lines from the top tap to the bottom tap, and then a 5/16 to 3/16 converter and at least 75 feet of 3/16 tubing (with no drops in it) down to a collection point.

Then all the lateral line with drops cut into it are on 5/16, and less prone to clogging, but you get the benefit of a sap column in 3/16.

Thoughts?

[Sugar Bear]

I am not entirely sure what you mean. If the sap column rises higher in the lateral line than the lower taps (which should only happen if the drain end gets blocked, the tubing at the end with the lower taps is on flat ground or below the lateral line at that elevation, there is a clog or blockage in the line restricting flow, or the line is seriously overloaded with taps), then the problem is with the installation somewhere.

In a well functioning 5/16 gravity vacuum setup, how long in feet should the sap column be expected to be?

If mine is 60 feet long and rises 15 feet vertically above the collection barrel and their is a tree suddenly available to tap next to my line that is 20 feet from the barrel and 5 vertical feet above the barrel and I put that tap on my run, wouldn't I have back pressure into that tap from the 60 foot sap column and also be corrupting my sap column at that point where I put that tap in.

[DrTimPerkins]

In a well functioning 5/16 gravity vacuum setup, how long in feet should the sap column be expected to be?

It isn't that simple. Depends upon several factors, slope, number of taps, rate of sap flow from taps. However the sap column in a non-pumped system can be several feet long. The reason that natural vacuum doesn't build as well in 5/16" tubing compared to 3/16" tubing is that air slips by the sap (upward) more readily in larger tubing. In 3/16" tubing, the air is trapped (better) and is pulled/pushed down and out of the end of the tubing, which creates the vacuum.


If mine is 60 feet long and rises 15 feet vertically above the collection barrel and their is a tree suddenly available to tap next to my line that is 20 feet from the barrel and 5 vertical feet above the barrel and I put that tap on my run, wouldn't I have back pressure into that tap from the 60 foot sap column and also be corrupting my sap column at that point where I put that tap in.

If the end of the tubing were closed, you would develop pressure quite readily at those taps. Given that the end is open (to drain), and you have vacuum above that point and the sap is moving downward, and there is (presumably) pressure within the tree pushing sap outward, there is relatively little net pressure (or vacuum) generated at that point. A good deal will depend upon the conditions of the moment.

Pressure variations within the entire system (trees and tubing) can be quite complex, variable, and change a lot during a flow period. Trees can have positive pressure up to 30-40 PSI when the first thaw, and vacuum can propagate in them (from the tubing system) down to -29" Hg+. The pressure/vacuum within the tubing system is also quite variable depending upon a lot of things.

[DrTimPerkins]

Seems to me the best of all possible worlds would be 5/16 lateral lines from the top tap to the bottom tap, and then a 5/16 to 3/16 converter and at least 75 feet of 3/16 tubing (with no drops in it) down to a collection point.

Then all the lateral line with drops cut into it are on 5/16, and less prone to clogging, but you get the benefit of a sap column in 3/16.

Thoughts?

While it could work, the problem with this type of setup is that there is a LOT more air in a 5/16" line than in a 3/16" line. Vacuum is generated in the line by pushing or pulling air out of the line. In this arrangement, you need to move all the air out of the larger 5/16" line through the 3/16" line at the end. Air slips past the sap in a 5/16" line better than in a 3/16" line, so it would be less efficient in moving air out, and because there is also more air, it would take more time for the vacuum to build up. It will work, just not as well as a system completely constructed of 3/16" tubing. Now some people do use 5/16" drops. This is less of a problem because the total amount of 5/16" tubing (and air within it) is not large.

[berkshires]

While it could work, the problem with this type of setup is that there is a LOT more air in a 5/16" line than in a 3/16" line. Vacuum is generated in the line by pushing or pulling air out of the line. In this arrangement, you need to move all the air out of the larger 5/16" line through the 3/16" line at the end. Air slips past the sap in a 5/16" line better than in a 3/16" line, so it would be less efficient in moving air out, and because there is also more air, it would take more time for the vacuum to build up. It will work, just not as well as a system completely constructed of 3/16" tubing. Now some people do use 5/16" drops. This is less of a problem because the total amount of 5/16" tubing (and air within it) is not large.

Hmm... I might have a basic assumption that's wrong.

Let's take a simple setup where you just have a 100' 3/16 line, running tight down a constant slope, and you're running enough sap in it to create a column of sap in the bottom 50' of it. For the sake of argument, let's say you get 10" of vacuum at the top of the line.

Now compare that to a 200' 3/16 line. Everything is the same - running down the same slope, same volume of sap running through it, same column of sap in the bottom 50' of it. Only difference is there are 150' of line from the top of the column to where you measure vacuum at the top, instead of 50' of line.

Would the 200' line also have around 10" of vacuum? Or would all the extra air in the line somehow decrease the vacuum at the top?

Thanks,

Gabe

[Swingpure]

I purchased 500 more feet of 3/16” line today, as well as the single handed tool.

I kept thinking of slope as degrees, but it is two different things, which helps.

I have two runs where I can have about 8 trees then a 75’ run on a steep grade, to the collection barrel.i have a third run, that I have about 6 trees on a 40%+ grade that goes to a 7th tree also on a steep grade below. I could put a collection barrel there, but it would be the hardest one to get to. I could run to a group of another bunch of trees. It would be a 100’ run with no taps on a 3 to 5% grade, before meeting up with 5 more trees on a 5%+ grade and I could have another 75’ finishing run on a 5% grade to the collection barrel. My fear is after a very steep initial run, that the sap would bog down in the 100’ shallower run.

[Sugar Bear]

It isn't that simple. Depends upon several factors, slope, number of taps, rate of sap flow from taps. However the sap column in a non-pumped system can be several feet long. The reason that natural vacuum doesn't build as well in 5/16" tubing compared to 3/16" tubing is that air slips by the sap (upward) more readily in larger tubing. In 3/16" tubing, the air is trapped (better) and is pulled/pushed down and out of the end of the tubing, which creates the vacuum.



If the end of the tubing were closed, you would develop pressure quite readily at those taps. Given that the end is open (to drain), and you have vacuum above that point and the sap is moving downward, and there is (presumably) pressure within the tree pushing sap outward, there is relatively little net pressure (or vacuum) generated at that point. A good deal will depend upon the conditions of the moment.

Pressure variations within the entire system (trees and tubing) can be quite complex, variable, and change a lot during a flow period. Trees can have positive pressure up to 30-40 PSI when the first thaw, and vacuum can propagate in them (from the tubing system) down to -29" Hg+. The pressure/vacuum within the tubing system is also quite variable depending upon a lot of things.

To Clarify ... In your reply above can your words "at that point" be replaced with "at those taps" as to reference the previous "at those taps" in the same paragraph.

If so that would make sense to me and had not considered the relative indifference of the hydro dynamics at that location.

But somehow the effectiveness of the sap column and or the flow of the lower taps/drops within the column seem like they are being hindered.

[Swingpure]

When you hook the line to the very first tree of the run, do your drop line(s) connect to the 3/16” tubing after the intersection with the end line hook and the tubing, or just before it?

Thanks

[DRoseum]

Did you get the end line hook with the built in drop line barb? Like this: https://bascommaple.com/collections/mainline/products/laelh316

If so, drop line goes down to the top barb and your lateral comes off the side barb.

[Swingpure]

Did you get the end line hook with the built in drop line barb? Like this: https://bascommaple.com/collections/mainline/products/laelh316

If so, drop line goes down to the top barb and your lateral comes off the side barb.

No I got one that plugs the end and hooks onto the hose on the other side of the tree. I never saw the other ones, and these are the ones that CDL gave me.
The ones you showed in the link, would have been slick to use.

22508

[DrTimPerkins]

But somehow the effectiveness of the sap column and or the flow of the lower taps/drops within the column seem like they are being hindered.

The lower taps will mostly be "hindered" by the lack of vacuum. In other words, the pressure differential from the inside of the tree to the tubing is much lower compared to the taps higher up on the hill getting strong vacuum. Since sap flow is linearly related to vacuum level, it is not unexpected that the trees lower down (not getting much if any vacuum) will run far less.

[DrTimPerkins]

Hmm... I might have a basic assumption that's wrong.

Rather than go into a lot of detail, a quick analogy might be simpler.

Say you have a 3/16" line, 100' long, with one end plugged. You suck on the end with one big breath....what is the vacuum you can achieve?

Do the same thing with a 5/16" line set up the same way. One big suck....the vacuum you'll achieve will be less because you weren't able to suck out as much (as a total volume of the tube) air. Bigger lines = more air to remove to get the same level of vacuum.

[DrTimPerkins]

I kept thinking of slope as degrees, but it is two different things, which helps.

But they are related. It is the total elevation drop that is filled with fluid (minus whatever is filled with air) that determines the maximum amount of vacuum that can be generated. However if your slope is too low, frictional forces start to subtract from that. On low slope or flat ground, friction is too high, and totally negates any vacuum generated (even if you have a really long line with good amount of drop), and can even result in the build up of pressure. This is why 3/16" tubing is not suitable for low slope or flat ground. With good slope and good elevation drop 3/16" tubing is ideal...as long as you keep it clean.

[Swingpure]

But they are related. It is the total elevation drop that is filled with fluid (minus whatever is filled with air) that determines the maximum amount of vacuum that can be generated. However if your slope is too low, frictional forces start to subtract from that. On low slope or flat ground, friction is too high, and totally negates any vacuum generated (even if you have a really long line with good amount of drop), and can even result in the build up of pressure. This is why 3/16" tubing is not suitable for low slope or flat ground. With good slope and good elevation drop 3/16" tubing is ideal...as long as you keep it clean.

If you have the first third of the 450’ very steep (7 taps), the middle third, shallow (3 taps), but still sloped and the final third (0 taps) with about a 10 to 15° slope, should that work, or does the middle portion kill the whole thing?

[Sugar Bear]

If you have the first third of the 450’ very steep (7 taps), the middle third, shallow (3 taps), but still sloped and the final third (0 taps) with about a 10 to 15° slope, should that work, or does the middle portion kill the whole thing?

The middle part should not kill it but...

The best place for the very steep section would be where the sap column forms. The steeper that column is the better off you are. Your sap column should form from the collection barrel up and how long it gets is determined by how well the sap is flowing and the number of taps.

The slope where the taps are is not nearly as important.

Mine have been about 60/70' long at maximum flow generating 17 inches ( also my maximum ).

[Swingpure]

The middle part should not kill it but...

The best place for the very steep section would be where the sap column forms. The steeper that column is the better off you are. Your sap column should form from the collection barrel up and how long it gets is determined by how well the sap is flowing and the number of taps..

I actually walked the lines today, and I by passed some lower trees to make sure I had the “crux”. One of the two lines finishing off with an 80’ uninterrupted stretch at 35° slope and the second line finishes off with a 125’ uninterrupted stretch at a 25° slope. This line actually runs by a viable tree, but the tree is only 30’ from the collection area. I will put a bucket on that tree.

Both collection buckets are side by side and the wire that holds the end of the line, will hold both line ends.

[DRoseum]

No harm at all in including that final tree. You will get more out of it on tubing than a bucket and it won't reduce yield of upper taps at all.

[Swingpure]

No harm at all in including that final tree. You will get more out of it on tubing than a bucket and it won't reduce yield of upper taps at all.

Actually it might be a good test. Both lines start at identical elevations, literally feet away, and both end up at the same location. It would be interesting to see how each kine averages out, although the other line has more trees with greater diameter.

[DrTimPerkins]

Actually it might be a good test. Both lines start at identical elevations, literally feet away, and both end up at the same location. It would be interesting to see how each kine averages out, although the other line has more trees with greater diameter.

If the trees are different sizes, it will not be a particularly good test. Tree size has a strong influence on yield, so any effect will be swamped out one way or the other. For it to be a "good" test, you'd need a bunch (10-20 minimum) of nearly identical lines (same number of trees, same average diameter, same slope, same aspect, etc.), half set up one way and half the other.

[Swingpure]

This may sound like a silly question, but when you start to tap the trees and hooking up the drops on the line, do you work at the highest elevation down, or at the bottom of the run, upward? I can make an argument for both ways.

Thanks

[Sugar Bear]

I actually walked the lines today, and I by passed some lower trees to make sure I had the “crux”. One of the two lines finishing off with an 80’ uninterrupted stretch at 35° slope and the second line finishes off with a 125’ uninterrupted stretch at a 25° slope. This line actually runs by a viable tree, but the tree is only 30’ from the collection area. I will put a bucket on that tree.

Both collection buckets are side by side and the wire that holds the end of the line, will hold both line ends.mm

From experience ...

At about mid season, 3 seasons ago my highest potential natural vacuum run had 9 taps on it. 6 taps up high then 65 feet to 3 more taps just before the collection barrel. After I removed the three taps and put those 3 taps on a individual line into the barrel and put the upper six taps on a undisturbed run into the collection barrel. Within hours the 6 taps were flowing better then they ever had before, even with the 9 taps on them. In addition the three tap line was then flowing sap at a decent rate but not even half as fast as the 6 tap run which obviously was in a natural vacuum state of obvious benefit.

Last year I had 3 on one line into the collection and 7 on another line into the collection. The 7 generated 17 inches at peak and was very close to a constant stream at peak flow on 5/16.

Now keep in mind ... I use 5/16 for whatever I do and get. If you use 3/16 results might be different I suppose.

I respect everybody's opinion on here, but about 5 years ago a humble soft spoken lady who worked at the Rutland Leader store and ran/runs a decent size commercial operation in Benson told me that "I think" you need at least 75 feet of good sloping final run after your "LAST" tap to generate decent vacuum on 5/16 and of course the appropriate number of taps and sap flow above it.

After lots of stumbling and perhaps not wanting to take a woman's word for it mainly cause I only had the 70/75 feet of final run on one of my runs, that piece of taping info I received from her has been VERY consistent with my experience in my gravity runs and not just this one.

Unfortunately the Rutland Leader store is no more.

With that said Dr. Tim Perkins does have me convinced that mathematically/physically speaking it should not matter. As he describes it and now think of it for what it is.

But .... my real world experience does not seem to back it up. Simply put the lower taps "seem" to reduce effectiveness for me. Both in forming vacuum on the upper taps and the efficiency of the lower taps.

Like everybody else on this planet it is very possible I am mistaken.

Rob

[Swingpure]

Today I paced off the planned lines, just to make sure I had enough tubing. At first I allowed three foot for each step, but then realized a large pace is three feet, but my steps were closer to two feet. So I grabbed a 100’ tape and then accurately measured off one line. It was very close to the 2’ per step measurement.

That left me confident I had lots of tubing, so for my first time, I made the drops for the two lines. I likely will run a third and a short fourth line, just for the purpose of consolidating collection points and do not expect much natural vacuum bonus from them.

The one handed tool was cool to use for the first time. I can see now how important of a tool it is. Likely in three to four weeks I will be running the lines.

[Swingpure]

On one of the lines, I wanted to add a 22” diameter healthy tree, but was a little concerned about the zig it put in the line direction, but more concerned if I would still be able to maintain a good slope.

I used twine to simulate the tubing and ran 150’ of it connecting to some of the trees on the line. I also used a line level to make sure there was a good drop. I had good slope for all of the trees. I painted a small mark on the tree where the twine crossed it. I also took advantage of the opportunity and cleared away any obstructions in the actual path of the twine and eventually tubing. I left today’s twine up. The highest I had to go up on any tree was 5’ and most were 4’ from the ground.

Tomorrow I will run more twine, to help me identify any obstructions along the path of the other lines, so that when it comes to run the actual tubing in about a month’s time, it will go as smoothly as possible.

Edit: I put twine on the other line this evening and finished putting twine on the first line. There was one large tree I though I might want to add to the first line, but by doing this exercise, I was able to eliminate it because of elevation and it was too big of a zag.

[Swingpure]

As mentioned in the previous post, when I ran my practice twine line, I zigged to a 22” tree and was able to maintain my slope. It haunts me though, that I am breaking a cardinal rule of not going basically straight with only some S turns.

The 22” tree is a little difficult to get to as I plow a lot of snow from my driveway between the road and the tree and would continue up to do so anytime it snowed. If I could incorporate it into the line it would save time and effort. However it would not be worth it if it sabotaged the line.

What would you recommend, skip the tree or incorporate it?

The yellow lines are the straighter route skipping the tree and the red lines are going to the tree in question and to the next tree.The x’s are the location of some of the trees in the line.

22522

[DRoseum]

If you have adequate slope it will be just fine.

[Swingpure]

Thanks.

I guess to get good vacumn, one the keys is a significant drop, especially at the end. 3 of my lines will have a 30 foot overall drop with a long run at the end. The fourth line will have a steady drop the whole way, but will only be an overall drop of maybe 15’ with 12 taps. It will have a long run at the end of 75’ with about a five foot overall drop.

Although I will not see high vacuum numbers, should I still get as much as with buckets and maybe a little more, with the bonus of one collection point?

[DRoseum]

You will get more on this tubing setup than you would on buckets.