3/16 pulling sap over a hump, how high have you gone

[buckeye gold]

I have all 3/16th lines with only natural vacuum. In past years I have run across my woods roads and cut the line open after season. I was thinking about elevating my line over my main road so I can drive under with the tractor (need 8 feet clearance). If I run the line up 8+ feet and then right back down on a tree, do you all think I will be able to pull sap over that hump. The remaining fall to the main tank would be approximately 10-15 feet fall in 300, elevation above the hump would be about 15 feet in 200 length. so there is between 25-30 feet of drop in a 500 ft run naturally.

[maple flats]

I have 3 lines that cross my driveway next to my sugarhouse. All 3 are 3/16. the lines on the opposite side of the driveway are at 36-40" off the ground , then I have each going thru a end tree hook. The part that would normally go up to a tap, goes up 15', then across the driveway to another tree. from there all 3 slope down at about 30-35 degrees to where they tie into a 1" mainline which has 27" of vacuum on it.
When I first hooked the original 2 lines in this group, I started tapping at the far end which is 4' lower than the location where the 3 current lines climb up and over the driveway. The sap was running that day. I was surprised that the pressure in the tree actually pushed the sap up to the end tree hook, and then up to 15' above the driveway, across the driveway and back down to roughly level with the tree where it had made the climb, and I got my hands soaked hooking the line into the main. Pressure in the line had pushed one line up hill about 4' to that tree, then up to 15' (11+ feet more) on the first line, and a distance thru 3/16 of about 400' of lateral. One the second line it started about 5' lower than the level at that end tree hook (elbow) and a distance of about 550' feet thru 3/16 tubing, then climbed the additional 11+ feet to get to a total climb of 16' (11+5). That line also soaked my hands as I connected it to the mainline. On the 3rd line, I added that the next season, before sap flow. It is 6' lower at the far end, has over 600' of 3/16 lateral, then climbs that same climb and ties into the mainline. That didn't get my hands we because no sap was flowing yet.
The thing I've found necessary is I change all tees before every season, and I use 3/16 x3/16x 5/16 tees, so all of my drops are 5/16. I used to change my drops every 3 seasons, but after a comment by Dr Tim, I now only change the taps and tees (ant if I have any connectors in the lines I change those too).
With gravity giving you a boost, you will have no problem climbing up over that height.
The issue with mine is that I'm pulling from lower areas, thus without the high mechanical vacuum my flow would be far less. Yes, I could get more sap, but in my mind, it would cost more than I'm willing to put into it, since I'm now 74 and really don't know how much longer I'll continue doing maple.

[buckeye gold]

Hey Dave, I just thought of this scernario:
Dig down 6" at the road and push 3/16th through conduit (iron pipe) and then back up to the next tree and tap and cover the conduit. Which do you think would be best?

[maple flats]

That would work, but freezing would be a problem. Since the driveway is always plowed, frost would be down 4' or more, thus if the line went thru conduit 6" or even 2' down, it would freeze and most likely would not flow until the frost came out of the ground. No good! Besides, it works very well the way it is. The sap loss I'm likely getting is because of line friction, but to watch it flow I'd never guess it. However I've not timed the flow speed compared to other areas in my bush where the sap ladders are less lift. I have none that are no lift. the only areas where I don't need a sap ladder are only 5 laterals in 5/16 that enter the 1" main near where the 3 lines in 3/16 enter. Everything else has 2 sap ladders and about 80-85% of my taps are into 3/16 laterals.

[buckeye gold]

The freezing never occurred to me, but here in southern Ohio we rarely get a deep frost line. Still it would be enough to not thaw easily. Snow cover is also sporadic and rarely season long....we just have tons of mud

[minehart gap]

buckeye, your scenario will work if you elevate your laterals over your drive as long as you have taps downhill of the drive to create vacuum. The "suction" created by the 10' to 15' down grade of where your lateral will be elevated will suck the sap up over but the trouble that will happen is when the temp drops your sap will freeze where it has to go upgrade then that will be the last sap to thaw. It is really pretty cool to see the sap move up the tubing without the help of a pump of some kind.

I have a lateral that has 18' of rise before it goes down 40' +/-. I get 20" + vacuum at the end of that lateral.

[buckeye gold]

-Thanks guys, I was pretty sure it would work, but wanted to hear it from people who have done it. I only need 8-9 feet to get the Kubota UTV and the tractor under it. I do have taps and downhill line after the hump. when I run the fish hatchery we moved thousands of gallons of water by siphon. We moved water over a mile with siphons. With that any leaks would kill our flow, so it made me wonder about taps, I never considered tree pressure creating the flow.

[maple flats]

Except for some line friction, if the sap climbs 9' on one side then drops 9' on the other side you will have almost no affect on the flow, especially with additional fall after the fall of 9'.