3/16 tubing to 3/4'' main line vacuum ?

[grimmreaper]

if all my 3/16 tubing runs into my 3/4'' main,will the vacuum continue in the main line if its full of sap with no leaks?

[maple flats]

No. In anything 5/16 and larger you lose the 3/16 advantage because the air and gases pass over the sap. It is only in the 3/16 that they do not separate and that is how the vacuum is created when used with good drop in elevation. When you look at the 3/16 in action you will see a steady flow of sap-gases-sap-gases etc, they remain segregated. For each 1 of sap column you get .88" of vac, thus if the sap column is 60% of the tubing length in 1' of drop you get 60% of .88" vacuum or .53" (actually .528"), if you have enough feet of fall at that rate you will get 27-29+" of vacuum, if you have no leaks. With the 3/16 you want more taps/lateral for best performance. 15-35 is suggested, I have 20-33 on mine.
Even if you only have 10-15' of drop you can get decent vacuum, but not great simply by using the 3/16. With it, you also do not want short runs, as long as you have more drop in elevation, keep going. I have some that are from 200-250' long

[grimmreaper]

so i have on average 20-25 per lateral,with about 150 to 225' of line on each run...so would i benefit to run 3/16 back to collecting point?it would add 400-500 feeton the far end then decreasing before the first tap on ea. run.
so should i use the main line of 3/4'' or 3/16 back to tank?

[PerryFamily]

Tim Wilmot said at Bascoms last summer the mainline should be vented on the far end
It is basically a trougth ( spelling?)

[DrTimPerkins]

Tim Wilmot said at Bascoms last summer the mainline should be vented on the far end
It is basically a trougth ( spelling?)

Not in a hybrid (3/16" + pump) system.

[PerryFamily]

Dr Tim your correct
I almost added that info

[grimmreaper]

if i added a vent,would it have to be higher than your highest tap? or sap could run out the vent???????

[can'twaitforabigrun]

No venting of the lateral lines. Tim Wilmot mentioned possibly venting the mainline. Dr Perkins, are you aware of any advantages to venting the mainline? Any difference in yield, sanitation, flow due to venting the mainline? I always thought that venting of any lines was not recommended. Lastly, doe Mr. Wilmot have an email address at his new position now since he has left Proctor?

[Bfouts]

I'm glad I saw this post. So let me
Ask this. Should I not run my 5/16 in to a 3/4 mainline with out a vacuum? What I think I'm reading and understanding is that I would lose vacuum by doing so. I should just run 5/16 line for main and lateral lines?

I'm not sure if what I have asked makes sense.

Sent from my iPhone using Tapatalk

[WESTVIRGINIAMAPLER]

I tried venting of mainlines this year for a day and think it is a bad idea. I didn't vent any last year and don't see any benefit to venting. All the sap starts to freeze up at night, it backs up in the mainline and the sap blows out of the vent and runs everywhere. I imagine it would do the same in the morning at the tops of the mainlines and laterals which are going to thaw out before the lower elevation mainline and laterals. I didn't see where sap traveled through the mainline any better vented.

[maple flats]

I'm glad I saw this post. So let me
Ask this. Should I not run my 5/16 in to a 3/4 mainline with out a vacuum? What I think I'm reading and understanding is that I would lose vacuum by doing so. I should just run 5/16 line for main and lateral lines?

I'm not sure if what I have asked makes sense.

Sent from my iPhone using Tapatalk
With the 5/16 you get no natural (gravity) vacuum, only in 3/16 and enough slope to generate the vacuum.

[maple flats]

Vince, Maybe I'm missing it, but what is your elevation drop from start to the tank? Also from where you are thinking 3/4" mainline to the tank?

[grimmreaper]

maple flats<my elevation is about 15-25'....my laterals down the hill (vertical)then my main line is horizotal at the bottom of the hillside.from the tank to the other end is around 400-500''....so to gain some vacuum at the first tap on the bottom of the ,i ran the 3/16 down the main line for about 80',then about 65'right down to about 15'(then six lines enter a 6-way star)
then i ran single laterals to saddles(again i ran the 3/16 down 20' then to a saddle for the next 6 runs)

[maple flats]

If I'm picturing that right, it sounds like it should work. Now, if that 3/4 has a vacuum pump I'd tie the 3/16 in when they meet the main as long as it has at least 15' of drop, then the main with the vacuum will add to what the natural vacuum gave. For example, 22" on the main and 12" on the 3/16 without vacuum will net the max. possible on that day depending on the barometer, 28.5-30?