VIDEO: Is this natural vacuum?

[Starting Small]

I am wondering if the air in these lines is indicating natural vacuum or just normal flow on gravity? This guy has about a 3% slope I believe and about 50 taps on this 5/16 line based upon some other videos of his I saw. Is there anyway to determine if someone with a setup like this actually has natural vac? Thanks,
-Dave

http://www.youtube.com/watch?v=H-6JYKAEqE0

[SandMan]

Both....as the lines fill with sap during a good run (slug flow), the fluid in the line that is traveling down a slope creates natural vacuum. The steeper the slope and the more fluid, more natural vacuum. The air bubbles are normal as the trees put out both sap and air.

[Starting Small]

Ok thats what I was thinking but then I thought I read that without a steep slope that natural vac would not occur. Then I saw this video and the guy is on mostly flat land and adjusted the height of the tubing on the trees to achieve his slope. Thanks,

[DrTimPerkins]

Ok thats what I was thinking but then I thought I read that without a steep slope that natural vac would not occur.

1 ft of slope on a sap-filled line = approx 0.9" Hg vacuum. So by having the taps 5 ft high, and the outlet on the ground, you would produce about 4.5" Hg of vacuum. To get good vacuum with 5/16" gravity tubing, you need a bunch of taps 30-50, good sap flow to start the process, and a decent change in elevation 28-30 ft. By using smaller tubing, you can develop natural vacuum with fewer trees and lower flow.

In this case it probably wasn't so much the tiny amount of natural vacuum change. Instead, it was likely just that with a steeper slope the sap in the line would run down faster.....sort of like a wheel rolling downhill. Low slope = low speed. Steep slope = higher speed.

[TerryEspo]

Maybe I need new ears, but that video was hard to hear. Did he say that the lower angle, tube out of the barrel DID or Didn,t give more sap ?
What way was giving him better flow ?
Terry

[adk1]

That is a pretty neat video. Thanks for posting. and no TerryEspo, about 1/3 of the way thru it started to sound like the Muppets

[GeneralStark]

I think the only way to really tell if there is a "natural vacuum" being created by the sap flowing through the 5/16" line would be to T a vacuum gauge into the line or to plug a tap into the gauge. The flow rate out of the tubing doesn't really suggest anything about the level of vacuum in the lateral.

In Tim Wilmot's study on 3/16" tubing and natural vacuum, he used vacuum gauges throughout his tubing system to determine the vacuum levels.

That said, you could anecdotally determine if there is natural vacuum by pulling a tap and listening for suction.

It bothered me that the guy that made the video posted something with such horrible sound and filmed sideways but it is youtube. And, what's up with letting the sap flow onto the ground?

[Starting Small]

Ya with the sound he dropped his phone in the barrell of sap half way througg the video that is why it gets muffled in the middle.

[Wallopt]

Thanks for the post. I will be using tubing for the 1st time this year. It's nice to see a video! I have to remember to hang on to the phone!!

[TapME]

I made some videos of 50 taps on 5/16 tubing and posted it on youtube. Go to saphauler channel and check it out. If I remember the slope was about 30 feet and the line was 100feet long. the day I was there it was pulling an amazing amount of sap. It must have droped 20 gallons in the 1.5 hrs there. If I knew how to attach the link to a post I would do that.

[DonMcJr]

Here's TapME's Video... That's some Vacuum!


http://youtu.be/MlaJOrsAigw

[TapME]

Thank you Don for posting that.

[DonMcJr]

Welcome! Just hit "Share" on youtube then copy the link. Then hit the filmstrip looking Icon and paste it in the popup box...