sap ladder downhill

[MahoskyBrosMapleFarm]

has anyone ever installed a sap ladder that goes downhill, for instance if you were coming down a grade of about 11% and u wanted to keep your mainline at about 5%, our mainline is going to be about 1300 ft long and at that much change in grade by the time i got to the sugar house we would be sky high with the main, so should we just run with the natural grade, it stays pretty consistant, or should we keep 5% percent and just put a sap ladder but in reverse where the sap goes down the spiders? Also could u use that same technique if u were going over a secondary road downhill?

[jrthe3]

i don't know about the sap ladder idea but i had same set up behind my sugar house all i did was bolt a 16 foot 4x4 to the side of the building and ran mainline to top of that and what the slope was it was (i thing it ended up like 8 0r 9 %) and strait down from there to the tank

[Haynes Forest Products]

What is the problem running with the natural grade?

[WESTVIRGINIAMAPLER]

Definitely higher quality sap with the higher the grade % as the sap don't have as much time to heat and more slope means less likely for any low spots to develop in mainline during slow runs or when sap is not running.

[MahoskyBrosMapleFarm]

aight than ill just run with the natural grade, the only reason i had thought of that idea was because ive heard to keep somewhere between 3-5% but ill def. keep it at the natural grade then, thanks guys

[sapman]

The problem with too much grade is that your pipes can fill with sap, not leaving any room for vacuum transfer, assuming you are using vacuum. Even if you aren't, might want to plan for it in the future. So I'd go with the slope, but definitely run wet and dry line, joining them occasionally (ideally where you branch off with a mainline to run 5/16s into), and not running any 5/16s directly into the wet/dry line if that's practical.

Hope this helps,
Tim

[maple flats]

If possible you should transverse the slope at a 5% and make your laterals go straight up the slope. Lateral (5/16 line) should be as steep as possible, mainline of 5 or max 10% are better that steeper. This is according to seminars I have attended and not on personal experience.

[Haynes Forest Products]

I have been to alot of seminars in my life and I would love to know what possible logic that says that a 5% grade is better to get a liquid to run down hill than a 45% grade. ITS water with 2.5% sugar in it so lets treat it as water its not Maple Syrup its water. Water running down hill in a 1" pipe with alot of feeder lines (latterals) into a releaser or vacuum tank is not going to be full of liquid its going to be sporatic in the flow. With vacuum what possible harm is done with a steep grade. I have seen cisterns in the mountains that feed water into cabins and they are a 3/4" line that runs from a up hill spring down 1000ft and I didnt see any transversing going on and they ran free.
The steeper the grade the faster the water collum runs down hill the more natural vacuum it creats and with mech. vacuum assisting the process I see no reason the water/sap wont run like a runaway train.
Water running down hill un obstructed starts to creat natural vacuum and if you make a small hole in the pipe you will get a sucking sound drawing in outside air or in the case of 5/16 latterals you draw the sap into the flow. 3000 taps cant possibly fill the line and create back pressure.

[brookledge]

I would say that if you had a steep slope that then leveled off it would create a bottle up. If you were trying to get vaccuum through it would create vac. transfer issues. That might be one reason you may want to keep the mainlines constant. Of course with wet/dry lines there would be no problem.
Keith

[sapman]

I don't disagree that the steeper the slope the faster the sap gets downhill. But with a steeper grade you are going to limit the vacuum getting to the taphole if that mainline fills with sap, it seems to me, and from what I've been told. I have a 3/4" wet and 1" dry line serving 575 taps on a hill, and at times the 3/4" will be completely full of slugs of sap then gases where it runs steep then levels out some. I'm confident that the 1" is still keeping the vacuum up as evidenced by the gauges on the hill, but if it was only on the single pipe, I bet I'd have drops in vacuum on the good runs.

So I agree with Haynes that there's no issue with back pressure, but simply with getting consistent vacuum to the taphole at all times.

Just my opinion.

All the best,

Tim

[WESTVIRGINIAMAPLER]

I guess I should clarify on my post that I was referring to was natural gravity, not vacuum. I can see where a very steep grade could create problems with vacuum especially if it was not all the same grade.

[KenWP]

What is a dry line. How could you possibly keep sap out of one line and still have it conected to the vacuum line.

[yarg]

The dry line is installed inches above the wet line and sap takes the low road. The dry line is there to get vacuum out into the bush..and is an alternate route for sap if your wet line is frozen or at peak run if the wet line is too small.

[Haynes Forest Products]

Plus the dry line is connected to the wet line with a vacuum booster that is a larger diameter section of pipe so the sap cant get sucked up into the dry line. The name vacuum booster is a little misleading because its more like a vacuum seperator it stops sap from climbing up the pipe because of its size so it keeps sap following to the path of least resistance wich is the lower wet line.

[maple flats]

I think it is a matter of the difficulty of keeping the laterals going up the steepest slope and still having the mainlines that steep. The greatest advantage comes from having the 5/16 as steep as possible, now by default the mains will be flatter to transverse the hill and pick up the laterals. It is also important to keep your mainline at a fairly constant angle, especially in a 1 line system, or the size may need to be larger to carry the flow from the steeper section if the grade flattens down hill. This was not just a liquid flow issue but a liquid (sap) and vacuum transfer issue. I think these issues are less critical for a wet/dry system.

[ennismaple]

Steep is fine as long as it doesn't flatten out at the bottom. A flat section of mainline below a steep section will cause the sap to "pile up" (a hydraulic jump from supercritical to subcritical flow) at the bottom.

[PerryW]

I think I finally had a eureka moment about understanding vacuum.

I think someone told me that Sap is 80 times more viscous than air. So any time you have a full mainline pipe of sap, it blocks the flow of vacuum in the upper part of the pipe.

Compared to air, sap is thicker than molasses.