3/16 spouts

[maplerookie]

Go to http://www.uvm.edu/~pmrc/ On the right side, in the "Recent Publications" section, there is a link to that paper about half way down the list titled "High Vacuum in Gravity Tubing"

I read that article or maybe it was his paper anyway there was a lot of data as well as good information. it looks to be very promising for producers that have some slope and dont want to use vacuum or cant use vacuum for whatever reason.
gravity

[GV2]

Thanks Tim. Indeed I have read that article a few times in the past. I thought perhaps the post was referring to another source of info. What I am still not understanding is the physics of the what we all will be trying to achieve in the tubing from the last/lowest tap to the storage tank/mainline. The question is the relationship of elevation drop and linear distance. I know we need a drop to keep the flow going. I know we need a column of sap to form the suction. When you all say we need a good drop in elevation is that because we need a reasonable atmospheric pressure delta? I kind of doubt it. Is it a good rate of speed of the sap in that section of tubing we trying to achieve? What threw me was that the post suggested that article said that elevation did not matter as long as you had 30 or 40 feet of tubing. If he is referring to the article you linked then I think he misread the information which implied 30 to 40 feet of drop. In any case in my 3/16 experiment next year I will have at best a 15 foot drop over 160 feet from the last tap. We will see what happens!