High vacuum in gravity tubing research

[Gary R]

As I mentioned, mine have not pulled out. I tapped mine on Feb. 9th. We've had a lot of freezing on lines full of sap. One question would be are you using 3/16 tubing from D&G? It is very supple like 5/16 drop line tubing. It collapses around the single barb well. If you had a break and need to get it going, Tim Wilmont told me you can add a pint of water at the top of the run. It will fill the line and create the high vacuum needed to get the trees running.

[CampHamp]

I had 6 fittings pop out yesterday. I'll need to walk my lines every day to inspect/repair. I think they popped this time during the thaw around noon and sap just running into snow. The lower sections must have been frozen while the upper trees were pushing sap out.

For tubing, I'm using the first company that Tim Wilmot provided in his paper, Hudson Extrusions Inc www.hudsonextrusions.com. The tubing is hard, nothing like the blue 5/16". Is that what D&G sells?

I don't want to throw-out all this tubing, I've got $250 dollars in it. When a coupling fails, I now replace it with a foot of 5/16 and over-lap the lines quite a bit. I hope this will act like a pressure buffer. I think I'll be buying 5/16 T's and connect them in the same way.

Anyone selling snowshoes?

[Gary R]

CampHamp, did you specify HDPE tubing from Hudson? I was going to buy from them because their price per foot is way cheaper than D&G. I did not like that it was in 100' rolls. Dave Y was at D&G for a maple supply run for his dealership. He called me and said he'd haul back the tubing for me. I jumped on it. The D&G is very soft. Tim Wilmont isn't on the trader. Maybe contact him or Dr. Perkins can speak up as to if they actually used the Hudson tubing.

[CampHamp]

I asked for HDPE and the invoice said HDPE - it's a hard, translucent, white tubing. I certainly wish I had considered D&G at this point (!) but didn't know it was a different plastic.

I had 5 T's push the lines out today and one of my couplings that I had put on yesterday had pushed apart (this coupling used a section of overlapping 5/16"). I had overlapped about 1" yesterday on this coupling and so, today, repaired everything today using the same overlap technique with about 2.5" overlap (not easy to do) and clamped the 3/16 with the hand tool to make the surface rough for more holding friction, before inserting into the 5/16". I had a check-valve tap spit the tubing out on this same morning walk - seems like my sap expands more than others!

Next 2 days look like good run days, so I proactively replaced a bunch of other T's that had come off previously, hoping that by taking the 3/16" fittings out of more connections (with this extra-long overlap) it will keep things together. I cannot think of another solution, but am open to suggestions.

I don't mind being outdoors and getting some exercise and hope that I'm contributing to some sort of general progress for mankind...

Tim W had told me to do the overlap technique, so I remain hopeful that these repairs might last a while.

[sugaringcrazy]

I got the HDPE from Hudson too, and I'm regretting not getting the D&G tubing. I'm repairing lines every day. So far I have mostly been replacing the fittings, but I like the idea of overlapping with 5/16. Definitely turning into a pain in the butt! I'm also having tubing coming off the spiles too. So much frozen sap that is expanding and not getting through. This week is going to warm up and hopefully the lines with settle and flow good! I don't have vacuum gauges on yet, but they are coming, and I'm very curious to see how much vacuum I'm getting.

[CampHamp]

sugaringcrazy,

I drew this up, just to be clear about what I am attempting:

3-16-tube.jpg

I'll let you know if it works over the next few days.

[sugaringcrazy]

To clarify, you are using straight up 5/16 Ts and couplers then using the reducing fittings to go into the 3/16. It seams like a good way to do it! I got things all fixed up this morning and got a decent run. Still waiting for my vacuum gauges to see what kind of pull I'm actually getting.

[CampHamp]

So far there are no breaks on any of my 5/16 tube "overlap technique". Found another check valve spit the tubing and one 3/16 T break yesterday morning - I didn't look for issues today since it's staying cold here and won't run until tomorrow.

To answer... I'm not using any 3/16" fittings - not even reducers. I use a straight-up 5/16" T and put a short piece of 5/16" tube on it. Then insert my 3/16 tube directly into the 5/16 tube. If you look at that sketch I made, the blue line is 5/16 and the white lines are 3/16 and the only fittings needed are the 5/16 T's.

btw- I found a way to check faster for breaks and leaks in the last week... I have a 12v transfer pump (diaphragm type that can be run dry) that I use to pump up to my head tank. I now put that onto my main line and suck into my collection tank (no releaser system obviously so only works after all is melted). I turn it on and check the "lateral" connections to the mainline and if any are racing in, I know there is a line break. Just like the vacuum checks that big operators do, I guess, but really saving me time and only run it for an hour or so.

I wonder how much air people usually get in their lines. I seem to have much more air than sap, like 70% air, even with taps all tight. I wonder if many of my 3/16 fittings are not air tight, because I can't explain all this air just by looking at the taps. How is it looking for others?

[Gary R]

I have not had any strong runs yet. The last two days have run about one gallon per tap. My lines look to only have about 20% air. I think a lot of air means the trees aren't running well or leaks. Look at your tees. If there is more air and/or the bubbles are moving faster on the down hill side you have leaks. I haven't had a chance to even walk my lines for two weeks.

[Gary R]

The last couple of days have been good runs. well more than a gallon per tap per day. The lines are almost full of sap. I'd say only 1 or 2% air in the lines. Vacuum has been 24" to 27".Copy of 3-16 vacuum gauge1.JPGCopy of 3-16 vacuum gauge2.JPG