Sap going backwards?

[Bolen Creek]

I have 300 taps that come through a 6ft ladder. The ladder is 3 1/2" pipes. I have 25 in vac at releaser and 22 inches past the ladder which is approximately 1,000 ft away. My problem is I my 5/16 lateral are flowing backwards about half the time on the other side of ladder they flow normal. We have a few 3/16 lines past ladder that all flow normal it's just the 5/16 going backwards. The ladders seem to be working good, anyone have any suggestions

[spud]

I have 300 taps that come through a 6ft ladder. The ladder is 3 1/2" pipes. I have 25 in vac at releaser and 22 inches past the ladder which is approximately 1,000 ft away. My problem is I my 5/16 lateral are flowing backwards about half the time on the other side of ladder they flow normal. We have a few 3/16 lines past ladder that all flow normal it's just the 5/16 going backwards. The ladders seem to be working good, anyone have any suggestions

You have a leak or loss of vacuum. This happens to everyone at times. This is why I use the CV2 spouts.

Spud

[Ultimatetreehugger]

Spud, what do you get for production numbers each year using cv2s? What level of vacuum do you like to run?

[Bolen Creek]

I will rewalk it tomorrow and see if we can locate a leak, this is a new install added onto a existing bush. The old part has CV 2 in it. We found it weird that the 3/16 lines were flowing the right direction and the 5/16 where going backwards. The mainline is probably 500 ft long past the ladder and all of the 5/16 were going backwards

[bill m]

Are you sure it was really going backwards? Could have been an optical illusion with the gas bubbles moving in a direction and give the appearance of the sap going backwards.

[Russell Lampron]

Sap flows backwards when there is more vacuum at the tree than from the vacuum source. If you put shut offs in the legs of the ladder you can shut one of them off to see it that helps or makes the problem worse. It's a possibility that you need to add another leg to the ladder to handle heavy sap flow.

I have a 10' ladder with three 5/16" legs on 17 taps which is probably too many legs for the number of taps. On low flow days I can see that the sap doesn't make it to the top. I never see the sap going backwards though.

[Chasefamily]

I have the same problem on one of my lines. I have 4 1/2" lines to lift 8ft or so. I have seen the sap flow backwards many times, then all of a sudden it will suck and go all at once. I am going to put in a shutoff in atleast 2 of the 1/2" lifters as i only have 112 taps on this line currently.

[blissville maples]

When your releaser if you're running vacuum is dumping or swapping sides you'll get a few seconds where the sap stops and even goes backwards a little bit. As soon as the releaser finishes it should resume, the proper direction away from the tree. this happens because for a split-second the tree has more vacuum than your main line, because the vacuum pump had to exhaust the air from the releaser dump.

Sometimes I see the ladders pulsing because the vacuum is rapidly changing, probably do to chugs of sap coming through the other section of main line causing sudden fluctuations that don't last long

[Chasefamily]

in my situation i am using and electric releaser. Late last night i installed 2 ball valves in my ladder so that i can shut half of it off if need be. It was starting to freeze when i did so, so i am hoping to be able to try it later today.

I have the same situation that Boleen Creek has. I have 28-29 inches at releaser (and the gauge is very steady), then 26-27 at this sap ladder. Alot of the 5/16 on this line will go backwards before it goes forward. at the very end of this run it switches to 3/4 line for about 500 ft and at the end of that there is one 3/16 line. the 3/16 continues to flow into the mainline. although when the 5/16 chooses to finally go, the 3/16 picks up speed and flows into main even faster

[n8hutch]

My guess is that you are getting pooling somewhere in the mainline and it is temporarily reducing vacuum past the pooling/sap blockage whatever you want to call it, then once the vacuum pulls the sap past the spot and the sap/air can pass each other the vacuum is restored past the blockage, your 3/16 line is not relying on the added vacuum to flow so it is not as effected by the surge in vacuum.

This pooling could be at your ladders or anywhere in the mainline.

This is why I reluctantly put a small leak in my system to keep my Ladders clear. Fiddled with the Ladder alot until I gave in and tried the leak.

[DrTimPerkins]

Very simply (not perfect explanation in all circumstances), sap in 3/16" tubing under natural vacuum is being pushed down by the weight of sap above it (or, depending upon how you want to think about it, pulled down by gravity, which does not change and cause backflow), whereas sap in 5/16 lines is being pulled down by the pump. If the driving force (vacuum) changes during releaser dumps or small leaks or by interrupted air flow though pooled areas of sap in the mainline, backflow will result. When the vacuum changes in this way, sap can move backwards in response. The amount depends upon the circumstances. Some things reduce this happening (electric releasers and good leak correction) and some things mean it happens more (mechanical releasers, sap ladders, leaks, improper tubing system layout, installation or maintenance).

[spud]

Spud, what do you get for production numbers each year using cv2s? What level of vacuum do you like to run?

I’m always coming up a bit shy on hitting .5 per tap. I run 27 inches of vacuum in my woods. I think because my average tree size is 10 inches prevents me from hitting .5. My tubing is 9 years old.

Spud

[DrTimPerkins]

I’m always coming up a bit shy on hitting .5 per tap. I run 27 inches of vacuum in my woods. I think because my average tree size is 10 inches prevents me from hitting .5. My tubing is 9 years old.

Yup, that’s darn good for trees that size and 9 yr old tubing. Good case study for CV use and high-vacuum.

[Ultimatetreehugger]

Thank you Spud, I sell my sap and am slowly working up to 10000 taps. Trying to do anything I can to increase my yields so I think I might give cv2s a try. Do you clean your tubing?

[spud]

Thank you Spud, I sell my sap and am slowly working up to 10000 taps. Trying to do anything I can to increase my yields so I think I might give cv2s a try. Do you clean your tubing?

I have never cleaned my tubing and would highly recommend other not too also. I almost never have an animal chew and want it to stay that way.

Thanks Dr. Tim

Spud

[DrTimPerkins]

I have never cleaned my tubing and would highly recommend other not too also. I almost never have an animal chew and want it to stay that way.

Same here. Drops range from new to 11+ Yrs old. We don't normally replace drops, but do when we are doing experiments just to equalize everything.

Similarly with cleaning -- we don't clean tubing UNLESS it is for an experiment to see how some sanitizer works. I can tell you with a great degree of confidence that cleaning with bleach attracts x&&3@!!! squirrels. We have twelve test plots in one area. Four were bleach cleaned. All of those are having continuous squirrel problems this year, which means the entire woods in that area is having continuous vacuum issues, which will negatively affect our total production this season. The other plots we didn't use bleach in have way less damage, but still are getting some along the borders of the bleach cleaned sections. As long as I'm around we are DONE with bleach cleaning. Maybe rinsing would help (we let the first run of sap flow on the ground instead), but I'm not going to try it again.

[mainebackswoodssyrup]

10-4 thanks for the input. I ruled out bleach a while ago after hearing of some local guys having issues with squirrels. Then Dr. Tim reiterated that with his posts earlier this year about their issues. We can easily access our lines and pump water. If we do anything, I guess that will be it.

[DrTimPerkins]

The attached figure shows what happens with air/water cleaning (purple line) and other replacement style sanitation strategies. It really is not terribly effective...but makes you feel good perhaps. Not really worth the cost (labor) of doing it. This graph is for vacuum systems. Gravity systems will follow a similar trend, but just start out with lower yields.

21309

[Russell Lampron]

I stopped cleaning my tubing when I changed over to CV adapters which I did when they first came out and I have since changed over to CV2's. My tap holes stay open and I get good runs right up to the end of the season every year. Some of my tubing and drops are 15 years old. I never used bleach, only water when I did clean and noticed since I stopped cleaning that I don't get as much green algae in my tubing. Like others that don't clean I let the first run go on the ground.