3/16 performance

[PACMAN]

I have already made up my mind to run another 1000 ft. section of 1 inch line,the only diference is i am going to run 3/16 line as laturals. There will be 400 to 500 taps on this new line. The old line is 5/16 and has a guzzler hooked to it and it has 485 taps on it. Some are telling me that the 3/16 line will out perform the 5/16 line with the guzzler. Whats your thoughts people? I will tell you that my slope in my bush is between 6 to 10 deg.

[optionguru]

I ran one ideal 3/16 line last year with 7 or 8 taps on it and it consistently outperformed my 5/16 gravity lines. I would estimate that the 3/16 was 30% more productive if compared to a 5/16 line on similar slope and exposure. I also had a couple of large trees that I put two taps in each and ran the 3/16 down about 10' of elevation into a 5 gallon bucket and those were also more productive than similar 5/16 set-ups. I'm going to switch to half and half next year, I'm a believer.

[PACMAN]

Should I use 3/16 drops on the 3/16 laturals,or should I use 5/16 drops?

[maplefrank]

We used 3/16 drops.... 20-30 taps on a line....one line had 27-18"vaccum

[BreezyHill]

Pacman, How much vac is the guzzler developing on your system?

The slope is steep but it is the length of the run after the last tape that develops the draw that makes the vac.

When comparing 0 vac to 15" the number was a 151% increase in production. If you reduce your vac transfer with a smaller tubing you my be negatively affecting production.

I think the 3/16 is great stuff for those that have the slope and distance as Tim Wilmot published; but I think some are hurting production by adding 3/16 to a vacuum system if it was already running more vacuum than one will get from the 3/16 lines.

If you are going to take off the guzzler then see what you can get on the 3/16 for vac.

[PACMAN]

Breezy, Im not replacing the 5/16 system. I am putting in a new and seprite system beside the old system and running to new untaped trees. Shooting for 1000 between the two.

[Thompson's Tree Farm]

[QUOTE=BreezyHill;286068
The slope is steep but it is the length of the run after the last tape that develops the draw that makes the vac.


Actually the drop does not have to be after the last tap. Those taps that have less than 30 feet of drop to the bottom will not have max vacuum but they will have some vacuum and having taps at the lower level will not decrease the vacuum at the higher level. I think PACMAN will have a nice comparison.

[DrTimPerkins]

There are many ways to incorporate 3/16" tubing into your system.

1. If you have flat land, then 3/16" isn't indicated.
2. If you have good slope, but only a modest amount of fall, then you can use 3/16" to gain some vacuum, but it will likely only be modest levels of vacuum. The trees closest to the bottom of the hill will get little or no vacuum, and will produce similar to trees on tubing without vacuum.
3. If you have good slope, but only a modest amount of fall, you can use 3/16" in combination with a vacuum pump. The pump (guzzler, sap puller, other modest vacuum pump) can generate some amount of vacuum in your mainline, and the slope drop with 3/16" will generate additional vacuum. The effect is additive.
4. If you have good slope with a good amount of drop, then 3/16" can be used to generate strong vacuum. This can be done either alone, or in combination with a vacuum pump.

Why would you want to use 3/16" in combination with a good vacuum pump? There are several possible reasons. The first is that perhaps you have 24" Hg vacuum in your mainline, and 23" Hg in your laterals. By setting up the system with 3/16" and even a modest 10' drop, you can max out your vacuum at as high a level as your elevation permits. Since each 1" Hg of vacuum gains about 5-7% sap volume, you might get 20-45% more sap by doing this. Secondly, if the vacuum pump goes down for a period of time, you will still have SOME amount of vacuum in your 3/16" lines. Third....with gravity generated vacuum there are likely to be fewer vacuum pulses in the system that result in backflow.

As far as putting 50 taps on a lateral line.....that is probably too many. The line might not be able to handle all that under high flow situations. Secondly, it is putting all your eggs in one basket (line). If you get a leak somewhere, it will affect the vacuum and flow from that entire line and all your taps. Better to split it into 2 lines of 25 (or close to that) each, which won't overload the lines, and will give you some assurance that if one line leaks the other might still be good. Also better to split in terms of finding leaks. Less time consuming to find a leak on a line with 25 taps than with 50 taps. If one line is running fine with good vacuum, you needn't spend any more time looking....just go check the other. Otherwise you'd got to check the full length of that 50 tap line for problems.

[5050racing]

1199211992I removed all my 5/16 to 1/2" main lines after last spring,going to replace all with 3/16 after testing one run of 5 trees 10 taps 200' run with 30' of elevation unreal how that run performed.30" of vacuum !! Ran non-stop almost!had viewed the gauge when it read 30!

[mapleguy]

Has anyone used the leader check valve with the 3/16 tubing?

[maple flats]

While I use the check valves on everything else, I see no reason to on good natural vacuum, that vac never shuts off or pulses. I am adding some 3/16 on my steeper slopes and will just use the cheaper taps.

[DrTimPerkins]

Has anyone used the leader check valve with the 3/16 tubing?

I think Tim Wilmot (UVM Extension) may have tried them a few times in some of his work, but nothing extensive. We haven't tried them in our hybrid (3/16" tubing on pumped vacuum systems) yet, but likely will this season (we are adding several hundred new taps on 3/16" tubing to our system this year).

As Dave says, due to its nature, a gravity vacuum system doesn't experience the reverse-flow (backflow) pulses that a pumped vacuum system does. There is the possibility that a leak could cause some backflow though. There simply hasn't been enough work done to demonstrate whether or not CV spouts/adapters will produce an economic benefit on 3/16" tubing yet (either on complete 3/16" gravity systems or 3/16" hybrid gravity/pumped vacuum systems).

[mapleguy]

What about sap being drawn back into the tree as it begins to freeze up at the end of the day. CV'S were advertised as being useful on a gravity system as to not allow sap from the drop to backfllow into the tree as it shuts down after a run. wouldn't the same apply for a 3/16 system?

[DrTimPerkins]

What about sap being drawn back into the tree as it begins to freeze up at the end of the day. CV'S were advertised as being useful on a gravity system as to not allow sap from the drop to backfllow into the tree as it shuts down after a run. wouldn't the same apply for a 3/16 system?

Yes, that is one of the benefits, and would likely still apply. They simply haven't yet been adequately tested in a 3/16" setting, so I can't say for sure.

[Locust Farms]

Just wondering If anyone has checked natural (siphon)vac on a 5/16 lateral line that ends with varying lengths of 3/16 tubing, 15 taps or more. Thinking that 25' length attached could possibly gain max vac.
Hope to check this theory when sap flows here in southern Indiana.

Dwight

[pdr]

Considering the length variable alone, 25' of 3/16" won't produce max. vac. on a gravity system. It would take at least 30'+ of tubing, all of which would have to be run down the face of a vertical cliff. To get maximum vacuum on a 3/16" gravity system located near sea level, you must have at least a 30+ feet drop in elevation from the lowest tree to the outflow of the 3/16" tube - 2' or 3' less if the trees are at say 2500' above sea level. Additionally, there may be some flow-resistance issues with 5/16" tubing. Hope this helps.

[TRAILGUY]

yes and a total waste of time had 40 ' drop 200' long 3/16 low with last 100' 5/16 at top. got 4 " vacuum. changed to all 3/16 jump to 26" or better

[DrTimPerkins]

Thinking that 25' length attached could possibly gain max vac.

You will not get maximum vacuum in this way. Go with all 3/16". Read Tim Wilmot's papers at http://www.uvm.edu/~pmrc

Afternoon update: So I realized that people are going to be thinking WHY won't this work? The easiest way to think about it is that the WEIGHT of the sap in the tubing column is the driving force for developing the vacuum. The sap pulls down on the air at the top of the tubing. In creating the vacuum, the air molecules are pulled apart. So think of it as the sap in the tubing is a weight, and the air is a rubber band you are suspending the weight from. With 30' of drop, you have a big weight, and with 3/16" tubing you have a small rubber band (the air) being pulled on, so there is a large effect, and the vacuum level is therefore quite high.

If you take that same system, but put 30' of 3/16" tubing at the bottom and 5/16" tubing above that, your weight (the sap in the tubing) would still be the same, but the rubber band (the air at the top of the tubing) you're pulling on is WAY bigger. Therefore the "stretch" (vacuum) exerted on the rubber band in the 5/16" tubing is going to be FAR less.

[Locust Farms]

Thanks all for your informational replies. Dr Tim ,your reasoning makes a lot of sense. Answers my question.

Dwight

[psparr]

Dr. Tim, when are you running for president. Intelligent, but can still talk like a real human being. That's a rare combination now a days.

[n8hutch]

I Agree with Psparr, very good explanation, I think that's called being Articulate. I struggle with that personally.

[Goggleeye]

We are looking at replacing some runs. 10-30 taps on a run, minimal slope, say 5-10' drop over 100' - enough slope to use gravity, but last tree on run is usually at the collection barrel. Is there any point in changing over to 3/16 with our minimal slope? I would say on average, we might drop 3-5 feet from the last tree to the collection. I see from other posts, it won't provide maximum benefit, but will it provide some? I'll take anything I can get!

[Thompson's Tree Farm]

For each foot of drop, you will get slightly less than one inch of vacuum.

[DrTimPerkins]

.... minimal slope, say 5-10' drop over 100'

Yes, this will work, and should generate vacuum. Just make sure that the laterals do run downhill (use a sight level). Producers with truly minimal slope on their lateral lines (1%) should probably NOT use 3/16" tubing.

[jimsudz]

This is a question for all you 3/16ers out there,what should I expect to get per tap per run? I'm setting up a bush that will have 250-275 taps, all 3/16 and possible a diaphragm pump. I'm trying to figure what size tank I'll need to set if I collect every 24 hrs.I know there are many variables but is the old rule of 2gal/ tap enough tank? Thanks Jim

[eustis22]

When do people add the tees for the drops to their 3/16 lines? Before or during tapping?

[WESTVIRGINIAMAPLER]

Put it all in when you install your tubing unless T's have plugs on them and then put just spouts on when you tap or right before.