Air bubbles in line

[Lukie]

This is my first year on 5/16 gravity lines (no vacuum ) the sap was running good yesterday collected 70-80 gallons with 134 taps happy with that coming right into my shack ! My question is some of my lateral lines that go into my 3/4 main line had bubbles in the line but not moving is there still sap flowing when the bubble is no moving and I do have good pitch on the lines . I have 5-7 taps on my laterals . And no I do not have a vacuum gauge .

[tcross]

bubbles are normal. i believe its the tree gasses... i'm sure someone can elaborate on that. but yeah, you'll have bubbles... as long as they are moving slow, you're usually all good!

[Lukie]

bubbles are normal. i believe its the tree gasses... i'm sure someone can elaborate on that. but yeah, you'll have bubbles... as long as they are moving slow, you're usually all good!

That's my problem some lines the bubbles are moving and on a few they were not moving I looked at some of the YouTube video's and understand about the gas bubbles but if the bubble is not moving does that mean the line is not producing and just going to set there full of sap kind of like taking a straw and filling it up and putting your finger over the other end it will not drain?

[maple flats]

The ones where they appear not to be moving might be for trees that are just thawing.

[DrTimPerkins]

It depends upon the slope of the 5/16" line and the flow rate in the tubing. The air wants to move upward in liquid, but has a hard time pushing its way up in a small line. It can happen, but if the sap flow rate is high enough it'll push it down and into the mainline. If the sap flow is low, or the lines very steep (like in droplines), the bubbles can either remain in place or move up, and the liquid can move past the bubbles downward.

It's a bit different in 3/16" lines. Because the line is so small, the bubbles have no room to easily move past the sap, so they get pushed along and out...which is part of what creates the vacuum in the line.

[Lukie]

It depends upon the slope of the 5/16" line and the flow rate in the tubing. The air wants to move upward in liquid, but has a hard time pushing its way up in a small line. It can happen, but if the sap flow rate is high enough it'll push it down and into the mainline. If the sap flow is low, or the lines very steep (like in droplines), the bubbles can either remain in place or move up, and the liquid can move past the bubbles downward.

It's a bit different in 3/16" lines. Because the line is so small, the bubbles have no room to easily move past the sap, so they get pushed along and out...which is part of what creates the vacuum in the line.

That makes sense thank my lines are steep and some of the bubbles were moving up the line .