Can a mainline be to long?

[Drew Pond Maple]

About six months ago I found a bunch of sugars on my property back about 1500 feet. Then later, about three months later I found some more back even farther.
My question is can the mainline be to long on gravity?
My total mainline length would be over 3500 feet, with 3/4 inch. aprox. 350- 400 taps. I probably wont tap them till next year, but trying to figure out the tubing this year.
Slope is about 5-7% for most of the run with the exception of the last 300- 400 feet which would be about 2-3%.
Should I go with 1" pipe for the last 300 feet?
Slope is east to north east, so some shade is apparent. I'm a little worried about sap freezing on marginal days.
What options do I have with this set up?

Thanks..
Mike

[Sunday Rock Maple]

I'd ask your dealer to walk it with you and go with his recommendations to set it up for eventual vacuum when you can afford it. Personally, I don't use 3/4" for anything but I know a lot of guys do and get good results. Good luck!

[spud]

If 3/4 inch is what you have then use it the whole 3500 feet. You will not see the production a high vacuum system would give you but you will get sap. What I would do is use saddles on your 3/4 inch (not stars or 4-6 way connectors). The hope should be that you could add a 1 1/2 dry line above this 3/4 inch line in the future along with a vacuum pump.

Spud

[BreezyHill]

The flow reduction of the 2% slope area will greatly reduce your production. Capacity from 6% to 2% slope is a difference of 336 gallons/ hr to only 195 g/h on the 2%. That is a 42% reduction of capacity. I would strongly recommend going to 1" on the 2% slope as it has a capacity of 330 gallons/ hr. By transitioning prior to the slope change will reduce the bottle neck affect of a plastic fitting. 500' of mains will be a good investment. If in the future you decide to go vacuum a dry line will be needed. The 3/4 may be sized ok if you are running low numbers of taps.

Good Luck!
Ben

[Thad Blaisdell]

Breezy, you did read that this is for a gravity system right. With at most 400 taps. If he ever gets 195 gallons an hour I will eat my hat. He may get 50 gal an hour at the most.

3/4 is fine.

[Drew Pond Maple]

If 3/4 inch is what you have then use it the whole 3500 feet. You will not see the production a high vacuum system would give you but you will get sap. What I would do is use saddles on your 3/4 inch (not stars or 4-6 way connectors). The hope should be that you could add a 1 1/2 dry line above this 3/4 inch line in the future along with a vacuum pump.

SpudI will be on high vac someday. Do you need a 1.5" dry line? Would 1" work

[Drew Pond Maple]

Will the sap freeze at the end of the day? I don't know how long it takes sap to travel 3500' at 5-7% slope.

[unc23win]

Yes you will have sap freeze in the line most every night. Once you have vacuum you will have less sap freeze in the line depending on when you shut your pump off. The change of the slope lower slope is where most of the freezing will occur just try to have a steady slope with no sags. With the length of line you are talking about 1.5" for a dry line is better. Spud was basically talking if you have the 3/4" now use it and then get the 1.5" dry line later that is good advice.

[Thad Blaisdell]

yes unc23 is correct (so is spud) 3/4 will be enough to transfer the sap either gravity or vacuum but you will need a substantial dry line for that distance.

[Drew Pond Maple]

Yes you will have sap freeze in the line most every night. Once you have vacuum you will have less sap freeze in the line depending on when you shut your pump off. The change of the slope lower slope is where most of the freezing will occur just try to have a steady slope with no sags. With the length of line you are talking about 1.5" for a dry line is better. Spud was basically talking if you have the 3/4" now use it and then get the 1.5" dry line later that is good advice.Ok, so if I use the 3/4 line first then decide to add a 1.5" above for dry line, how could I incorporate a manifold to connect the two lines together? Wouldn't the wet line be full of holes from the saddles, cuz I would have to add branch mainlines?

[maple flats]

With that many taps on 3/4 you will do fine on the 6-7% slope. Go to 1" on the flatter portion.
Than when you can go to vacuum, add 1.5" above the 3/4". This will not be ideal but it will gain flow. Then you can step it up to a true wet/dry as you can afford by running a new 3/4" wet line and take appropriate length sections of the existing wet line, separate it out, put a plug at the high end and set up a whip on the low end to the new wet line. Repeat as needed as you work up the 3500'. A leader rep. told me once that 1000' is considered the max on 3/4" mains so you might end up with 4 sections or mains off the wet/dry. Also, the wet/dry only need to go far enough to get to the last main.

[Drew Pond Maple]

Ok that makes sense, using the 3/4" for branch mainlines after installing a new wet/dry line. So I should use a 1.25" or 1.5" line to reach the farthest point of the bush on a single line? Also would the larger pipe be fine for where the line levels off at the collection point so sap won't fill the line? Let's say I was high vac now, could I use a smaller line with a vacuum booster? Any thoughts

[unc23win]

Yea the 3/4 would stay like you are doing it now saddles and all. Then you would add the 1.5" dry line you can use a manifold/booster method (which is what Spud and I do) or the whip method (which is what Thad does) both ways are proven to get very good results. Basically the dry line will supply the vacuum while the wet line takes care of the sap. Although it is not 100% the case I think of it as the dry lines job is to pull the sap into the line and the wet lines job is to drain the sap. Either way once you get the 3/4" in the only changes you will have to make will be adding the dry line and connecting the two.

To reach the farthest point you wouldn't need a bigger line you can do it the way Flats says with whips taking the 3/4 and chunking it up into 1000' pieces as he says or you can do it with boosters/manifolds. You only need the bigger 1.5" line for the DRY line. For the wet some of us use bigger than 3/4" I use 1" Spud uses 1.25" but we all thought you already had bought the 3/4" if thats the case use it if not it is probably worth the extra money to go bigger now.

There are lots variables as to how you install it. There are some good books as well as PDFs available explaining setting up vacuum. Proctor Maple Research Center http://www.uvm.edu/~pmrc/ Cornell maple.dnr.cornell.edu/ books The North American Sugarmakers Handbook, Sugarmakers Companion, New York State Vacuum Notebook by Cornell and a few others.

[Drew Pond Maple]

What is the distance between the points at which the will be connected?

[unc23win]

Well that depends on the set up. Dave (maple Flats) is probably right about the 1000' feet max. So if you have 3500 feet and you want run the dry over top and use the whip method you would splice the wet and put in a whip to the dry maybe 3 or 4 places or more going up the hill. Thats assuming your 3500' run is straight.

Now if you have branches in your mainline you would connect using a whip at each branch. If you do it with booster/manifolds you would run your wet and dry to the booster then branch out the back of the booster to your taps using the booster method you have 1 dry connection for each booster (some use 2 to get more CFMS to the booster), where as the whip method will use more connections. To me its very interesting how the 2 methods are so proven to produce personally I like the boosters yes they cost more, but I like the idea that its easier to find problems and easier to isolate lines.

BTW boosters do not actually boost vacuum they are really just a vacuum transfer tank and do provide some what of a reservoir for vacuum but they can really only maintain the vacuum that is supplied to them they can't really increase it. Some companies call them boosters some call them manifolds and some call them transfer tanks.

How much vaccum were you getting with the sap sucker?

[Drew Pond Maple]

I connected two 400' rolls of 3/4" tubing together, vacuum gauge at one end and pump at other. 18" hg max after 45 minutes. That was done on my kitchen floor. I bought it in late April so I haven't used it in the woods yet

[unc23win]

Is that similar to the guzzler? I think the guzzler can get 20" plus (reported 23") and handle up to 500 taps. They have been discussed and they seem like a good route for someone starting out on vacuum. You have to remember there is a big difference between 18" of vacuum and gravity the 18" is well worth it.

[Drew Pond Maple]

With that many taps on 3/4 you will do fine on the 6-7% slope. Go to 1" on the flatter portion.
Than when you can go to vacuum, add 1.5" above the 3/4". This will not be ideal but it will gain flow. Then you can step it up to a true wet/dry as you can afford by running a new 3/4" wet line and take appropriate length sections of the existing wet line, separate it out, put a plug at the high end and set up a whip on the low end to the new wet line. Repeat as needed as you work up the 3500'. A leader rep. told me once that 1000' is considered the max on 3/4" mains so you might end up with 4 sections or mains off the wet/dry. Also, the wet/dry only need to go far enough to get to the last main.
So I guess the answer is yes. Mainlines can be too long.
Thank you everyone

[noreast maple]

I have a friend that has over a mile ,maybe closer to mile and a half , but he is using 1 1/4 main line.

[Drew Pond Maple]

I have a friend that has over a mile ,maybe closer to mile and a half , but he is using 1 1/4 main line.
Is he running a single 1 1/4" or a 1 1/4" dry line?

[BreezyHill]

DPM send me an email at bhffeed@msn.com I will send you the Steve Childs data and mainline calculation sheet. This explains the frictional loses of different lengths of mainlines in 1" size from 0' to 6000'. You can do the math from there to calculate other line sizes as needed.

To answer your question of too long...Yes but that depends on how many taps and the slope the line is maintained at. At 6000' you will only have 3 cfm, no matter how big your pump is; thus you can only have a max of 283 taps on a 2% slope. By going to 6% slope you can do 308.

Its all in the documentation and calculation sheets.

[noreast maple]

11/4 wet and dry line.

[Drew Pond Maple]

11/4 wet and dry line.. That alot of pipe. How many taps? How much vacuum that far out?

[Starting Small]

At 6000' you will only have 3 cfm, no matter how big your pump is; thus you can only have a max of 283 taps on a 2% slope. By going to 6% slope you can do 308. .

Correct me if I am wrong, but does this mean that the tap that is 6,000 ft away would only have 3 cfms reach it but taps that are much closer, say less than 500 ft, would have considerably more cfms. In other words on a long line the only taps that see a reduction in the cfms are the ones that are farther away from the pump? Am I correct on this or does the 3 cfms on a 6,000 foot mainline mean that all taps are only experiencing 3 cfms? Thanks,
-Dave

[unc23win]

Mike you will be fine with your 3/4 to start and then add the 1.5' dry line. Maple Flats was talking about chunking up your wet line (can be done with whips or boosters) when you add vacuum, this will help get the CFMs you need as you go out farther from the pump.

A 15 CFM pump will get you 8 CFMS 6000' on 1.5" dry line. That's enough for 500 taps at 3,500 feet plus add the 3/4" wet line and add another 2 CFMs. I have no idea the CFMs of the Sap Sucker, but I know this it will be better than gravity.

[BreezyHill]

The further away from the pump the less CF of product that can be moved thru the line, due to frictional loses. On a 1" line with a 15 cfm pump the amount of cfm available at 200' is 11, while at 1000' there is 7, and at 6000' there is only 3.

By adding a equally sized dried line you double the CFM, plus a tiny amount. Think back to chemistry clase and how the test tube of water had a concave surface for the top of the water. The water actually climbed the side of the tube. The water in the tubing will have a supper thin layer that acts like a lubricating or transferal surface, speeding the sap toward the pump. The dry tub will rely on air to do the same. The only issue is the air will be a thicker area and will not have the momentum capacity of the sap...sorry strated getting into the theory of fluid dynamics.



The larger the line the more CFMs that can be moved. The rub is that you cant use a direct relation of pipe size to CFM that is moved. There is an algebraic relationship due to not all of the diameter of a pipe will move the air. There will be a column of air with in the tube that moves with a layer around the walls and on top of the sap that is stagnated.

Since a 1" pipe has a volume of .785 (Radius squared x pi at 3.14)and 3 cfm at 6000' and a 1.5" is 1.77 that does not mean that the CFM of the 1.5" will be 2.25 times greater ((1.77/.785)*3Cfm)) for an answer of 6.76. The answer would actually be closer to 6.

This is why a wet/dry line works better than an over sized single line, y works better than tees, and how sap ladders can be made to function efficiently.