I think if I understand what your thinking that you intend to run you lines horizontal to the hillside you will be losing the advantage of the steep of your hill and the lines will not produce well at all?
110 taps W.F Mason 2x3 and two turkey friers for finishing
2011 expanding to a Mason 2x4 with a blower increasing taps to about 200
2011 Hurricane Irene rips thru my small sugar bush cost me to lose 20% of taps
2014 I have reworked my lines for 2014
32 taps on 5/16 line with check valves
57 taps on 3/16 line with check valves
55 buckets with total tapped trees of 144
Although having a portion of the lateral running at no or slight grade is not optimal, I always thought that total elevation change is what created the vacuum. If there is a good reason to have some of the tubing running level or even uphill, I think go for it. Again, not optimal, but any vacuum gain is an advantage.
Matt,
Minehart Gap Maple
The weight of the "hanging" column of liquid (which is generally the total elevation change) is what creates the force generating the vacuum in 3/16" line. But that is affected/counteracted by frictional forces in the tubing. If the tubing goes downhill well, the frictional forces are low. If the tubing is flat, friction is high. At some point, if the tubing is installed with too little slope (or totally flat), the frictional force can overcome the gravitational force and cause back-pressure. So it really is an equation.
Total vacuum (or pressure) = vacuum generated by elevational change - pressure generated by friction
The vacuum level can be different along the length of the tube. You might have great vacuum high up on the hill, moderate vacuum lower down, and then no vacuum (or even pressure) if you run the line across a long stretch at the bottom of the hill. Sap will still run through the tubing, but it will have to overcome the pressure at the bottom of the hill to move through the tubing (or as Matt said...it is not optimal). Same sort of thing can happen if your lines have too many taps on them.
Another way to think about it is as a bunch of bowling balls. If you have a nice steep drop, the ball will go down and build up a lot of momentum (force). If the pins are at the bottom of the hill, it hits them really hard. Take that same pins and move them a few hundred yards across the field. The bowling ball may not even roll far enough to hit them. If you toss enough bowling balls down, they'll pile up and eventually get pushed across to the pins. Depending where the pins (the exit of the sap line to the tank or mainline), and how far the balls have to run downhill will determine the force (vacuum) that is generated. It's best to have the pins (tank, mainline exit) at the very bottom of the hill, but while it is not optimal to have a flat area, some is probably OK, but too much is clearly not OK.
The easiest alternative when you hit that flat area....switch to 5/16" tubing. Less resistance.
Last edited by DrTimPerkins; 12-18-2018 at 08:08 AM.
Dr. Tim Perkins
UVM Proctor Maple Research Ctr
http://www.uvm.edu/~pmrc
https://mapleresearch.org
Timothy.Perkins@uvm.edu
I think one thing that needs to be considered in every scenario is, "what is your goal for the application?". For some it is to max out sap production and get every drop possible. For another it may simply be a matter of convenience or economy. So your goal dictates how optimum your install needs to be. If you need more sap you better keep it straight and down hill, as Dr. Tim says, if you simply want to make life easier then a few cross lines and low slope will work. In your scenario Dr. Tim you need to ask, "do I want the bowling balls down the hill as fast and soon as possible with as many as possible in that time or am I just happy that all I need eventually get there.
For instance, I do not need to max out my sap production. I do like getting more sap with less taps, but primarily I want to reduce labor. After developing some heart disease I struggled to manually gather from buckets daily. I simply want to get my sap to a point I can recover it with as little effort as possible. So I am happy if it just runs down hill to my tank. I went with 3/16th tubing because: 1.) It would be efficient and most likely I could reduce taps. 2.) it was cheaper 3.) it would be an easier install and repair 4.) I like engaging new tech. I get more sap than I can process in my hobby unit as it is and I have no plans to expand.
I agree, although I think the majority of producers (at least those we hear from) do care about how much sap they get. If your goals are simply to make life a little easier, then absolutely do it any way you want (the same does NOT apply to food safety issues though). However one really should know what "best and accepted practice" is, what the results will be if you do it that way, and how deviations from that approach can affect the results. We tend to focus on high yield, but our real philosophy is to maximize net profit for those producers who are trying to make a money from sugaring. If you aren't interested in making money, then obviously the approach can be quite different.
Dr. Tim Perkins
UVM Proctor Maple Research Ctr
http://www.uvm.edu/~pmrc
https://mapleresearch.org
Timothy.Perkins@uvm.edu
Oh I do agree with you Dr. Tim, I am a firm believer in knowing "best practices" and most are after max yield under best practices. I just wanted to throw out there the thought that not everyone requires max output and there is a little wiggle room under those circumstances.
I absolutely agree 1000% that any method that is easier that also compromises food safety or sanitation is out of bounds. I suppose that there are sanitation concerns with any tubing that does not drain well. Even though I am not concerned with max natural vacuum, I work hard at keeping every foot of my lines going down hill.