vacuum transfer in tubing systems

[DrTimPerkins]

In addition to work on the Check-valve spout, I've been working on measurements of sap and vacuum transfer, and ways to improve vacuum transfer (and hence sap production....since every 1" Hg vacuum increases sap yield by ~5%).

Some time ago I posted a presentation on sap and vacuum dynamics in tubing systems. This outlines some of the theoretical considerations and measurements we've done to better define the problem so we can develop solutions. It is located at http://www.uvm.edu/~pmrc/SapVac.pdf The dual-line video referenced in that presentation is located at http://www.youtube.com/watch?v=qI4mhesDuj0

Mainline systems have been fairly well optimized, with dual-line systems with manifolds and improved system design and layout resulting in better vacuum transfer to the lateral line system. There is seemingly little further improvements to be made in the mainline system (tweaks perhaps).

The biggest problem we've identified arises due to the fact that when sap is flowing in vacuum tubing systems with 5/16" lateral/dropline tubing, the sap forms a fairly solid column of liquid (with some air) in the tubing. This causes "slug" flow of sap (a very poor type of flow in pipeline systems), which reduces vacuum transfer to the taphole by 2-5" Hg(depending upon flow) under regular conditions, and perhaps up to 5-10" Hg during peak flows in poorly designed/operated systems (many taps on a lateral line/long lateral lines).

There are essentially three ways to ameliorate these vacuum restrictions in lateral/drop lines.

1. Dual-lateral line tubing (basically a wet/dry system for lateral lines),

2. Larger diameter (1/2" diameter tubing works well) lateral/dropline tubing along with fittings with larger diameters (this approach has many advantages), and

3. A "booster" device as a stubby with a large internal cavity (this is only moderately effective, but serves the dual purpose of causing a "break" in the sap column, so it also effectively reduces sap backflow to a substantial degree).

We've done a substantial amount of work on these approaches over the past few years. In general, options 1 or 2 (above) yield about a 15-20% increase in total sap yield. This coming season (2011), we will do a full-scale test of the large diameter lateral/dropline system (although technically the tubing and fittings don't exist yet).

UVM has filed patent applications for all three approaches in the U.S.A. and Canada, and will be searching for maple industry partners to license any of these over the next few years. I've started to discuss this research in some of my presentations, so thought I'd mention it here as well.

[ennismaple]

Sounds good in theory! As always I'm anxiously awaiting the results of your research.

I'm sure my grandfather and father are watching down and shaking their heads at all the science and data that goes into optimizing sap production today! I can hear them now: "In my day..."

[Haynes Forest Products]

The guy that I started helping due to his age wouldnt allow Vacuum because he didnt think it was right. His brother that let me take over the woods thinks that anything that has a gas engine hooked to it cant be all bad. Heck when the vacuum rig had a flat tire sitting in the mud he went and took it off and got it fixed:)

Dr Perkins When air passes over a siphon tube it sucks the liquid out we all learned this in science class. So why doesnt air that is being sucked past a siphon tube (5/16 latteral) benefit in the same way. Maybe we need a venturi at every 5/16 and maineline connection..............................OH BOY HERE WE GO

[DrTimPerkins]

When air passes over a siphon tube it sucks the liquid out we all learned this in science class. So why doesnt air that is being sucked past a siphon tube (5/16 latteral) benefit in the same way. Maybe we need a venturi at every 5/16 and maineline connection

Interesting question...thanks for asking it.

The venturi effect (a lowering of fluid pressure along with a corresponding increase in fluid velocity) is due to a restriction in the system. It requires there to be a flow of fluid (sap or air) that can change in velocity to function in the system. The sap and air in the 5/16" line can't move out of the line any faster than it does due to the cohesiveness of the liquid and the lack of sap/air that is able to move through the system (there is no "make-up" fluid).

Now if you put a big enough leak at the end of the system, then you might get a small venturi effect at the mainline/lateral line junction, but it would be offset by the fact that you have a leak lowering the vacuum pressure in the line. The result is that you don't gain anything.

[Jeff E]

The Leader recommendations for Lateral lines went something like:
Each lateral should be no more than 100'
Strive for 5 taps, no more than 8 per lateral
try and maintain slope on laterals.

With the sap filling the laterals, does the slope have that much impact?

Does the loss of vacuum at the tap get minimized following these recommendations, or to put it another way, do you have a list of 'no-no's' that really drop vac levels at the tap?

[DrTimPerkins]

With the sap filling the laterals, does the slope have that much impact?

Sap flowing downhill in a 5/16" line somewhat offsets the loss of vacuum transfer due to the development of natural vacuum. The degree depends upon the slope, length, and flowrate of sap. But given that you've invested in that wonderful vacuum pump, do you want to rely on natural vacuum to get the job done, or do you want to ensure that the vacuum in your mainline actually gets to the tree?


Does the loss of vacuum at the tap get minimized following these recommendations, or to put it another way, do you have a list of 'no-no's' that really drop vac levels at the tap?

Yes. Basically what Leader and the other equipment manufacturers say.....on a vacuum system, keep the lateral lines short and keep the numbe of taps on a lateral line low. A study we did years ago show that the best results (on 5/16" line) are achieved with 1 tap per lateral, and that you lose some yield with each additional tap on that line. See page 3 of http://www.uvm.edu/~pmrc/SapVac.pdf In general, you lose about 10% of your potential yield for every increase of 5 taps on a lateral line (under vacuum.....the guidelines on a gravity system are very different....in that case longer laterals and more taps are BETTER....to a point). The "increased lateral line diameter" and "dual-lateral line" treatments are designed to eliminate those losses.

Thanks for the questions.

[DrTimPerkins]

Sounds good in theory! As always I'm anxiously awaiting the results of your research.

It isn't all theory. At this point we've had 1-3 years testing some of these new approaches. We're talking about it now because it is nearing the "introduction/implementation" phase of development.


I'm sure my grandfather and father are watching down and shaking their heads at all the science and data that goes into optimizing sap production today!

Mine too. That's how I got my introduction to sugaring. Lugging buckets in my grandfather's sugarbush....helping my uncle gather and my father boil. Great memories, but sad that neither are here to see it.

Finally.....if you think this makes you shake your head.....the truly revolutionary stuff is about 5-10 years away. We won't talk about that for at least 2-4 years until we're fully convinced (don't bother asking). If it does work as we think it does....all I can say is.....buy bigger storage tanks and a larger RO.

[Thad Blaisdell]

If you need a test woods keep me in mind. I am of the theory more is better!

[DrTimPerkins]

If you need a test woods keep me in mind.

Thanks Thad. I'll add you to the list.

[Thad Blaisdell]

Didnt even know there was a list????? But definitely add me to it, I would love to participate in anything you have going.

[red maples]

[QUOTE=Finally.....if you think this makes you shake your head.....the truly revolutionary stuff is about 5-10 years away. We won't talk about that for at least 2-4 years until we're fully convinced (don't bother asking). If it does work as we think it does....all I can say is.....buy bigger storage tanks and a larger RO.[/QUOTE]

So now you got me thinking about this statement and I won't ask!!!!

but the thing that worries me a little is as we get more effiecient, better evaps (and all that go with them), ROs, Higher Vacuum, and all sorts of tech. improving everything, then will the prices drop and the demand go down because we are too Effcient. Similiar to assembly lines run by robots to keep costs down. I don't think The market for the little guy like myself and others on here will be effected that badly because of the high demand for local farming. but will the bulk prices as a commodity drop on the global market?? or will it just re-adjust itself over time.

Don't get me wrong I like progress but just curious.

[Haynes Forest Products]

IF MAPLE SYRUP WAS OIL????...................Why do we think the same principals dont apply. More supply ...lower price........we get better at bringing it to market......people use more at the lower price......people find new uses.......demand goes up as more people use it........prices go up..we produce more......prices go down.......more people start using it.

Along the way producers (you and me) invest more money to produce it faster and some producers quit because they cant keep up or cant afford to do it.

[DrTimPerkins]

.....but the thing that worries me a little is as we get more effiecient, better evaps (and all that go with them), ROs, Higher Vacuum, and all sorts of tech. improving everything, then will the prices drop and the demand go down because we are too Effcient.

Most likely won't be a problem. Not everyone adopts new technology, and even those that do don't do so all at the same time. So the ramp up of production would be gradual.

As bad as over-production can be, under-production is just as bad. When under-production occurs, the bulk price goes up (maple producers happy), the price for syrup in the large markets goes sky-high, and over the next year maple loses market share compared to other sweeteners (large markets don't like wide price swings or lack of availability of ingredients), and the price drops (maple producers unhappy). So there is danger both ways. What we're trying to do is to find ways to stabilize production....it may be at a higher level, but it will be more stable. The producers using high yield techniques don't normally see such huge swings in production from year to year.

[Maplewalnut]

I'm not too concerned with all the technology advances dropping prices either. will it become more of a commodity-probably. It there a world of untapped venues out there for the energetic producer with an eye on marketing-absolutley. Don't forget we produce a product that can only be 'grown' in roughly 15% of the country.

Now, if you told me the highs would be in the 40's and lows in 20's from feb-through april each year I would be a little more concerned but not much.

The other thing to do is purchase all your capital equipment now while prices are still up. Between depreciation and the syrup you make most is paid off in a few years and everything after that is gravy! (or medium amber)

[ennismaple]

Finally.....if you think this makes you shake your head.....the truly revolutionary stuff is about 5-10 years away. We won't talk about that for at least 2-4 years until we're fully convinced (don't bother asking). If it does work as we think it does....all I can say is.....buy bigger storage tanks and a larger RO.

Sounds good to me - I'll order 2 of whatever "it" is!

I'm all for change if it's for the right reasons. I prefer to look at parts of our operation and think if there is a better/faster/cheaper way to do things. Just because we've always done something a certain way isn't a good enough reason to continue. If you're not evolving with the times you're falling behind!!!

[red maples]

OH of course you need to get better every year thats almost everyone's goal I was just curious what the thoughts are on that.

I think maple as a sweetener is very important as it is about as natural as you can get!!! which is in a very high demand right now.

[maple flats]

I think the demand world wide has lots of potential for gowth yet. There have been good increases there but that will be the final answer. If we can develope and satisfy year in and year out the greater demand the price will be healthy. The worst part is too much fluxuation in production with too little reserve to offset a poor season. We are the only place in the world that makes maple syrup and a bigger market is needed to balance the prices. (But I think I heard that China has planted lots of sugarmaples)

[farmall h]

Just read in the paper the other day that Maple Grove is stopping their public tours due to possible product contamination per rules and regulations passed down by their corporate buyers...such a shame as to the world we live in today.:mad:

How do I post a new thread? This couldn't have been right.

[DrTimPerkins]

How do I post a new thread? This couldn't have been right.

Goto: http://mapletrader.com/community/forumdisplay.php?f=5 Click the correct forum for the post you want to make, then click on the "New Thread" link in the upper left.

[Bucket Head]

I know Farmall's post was off topic, but I have to agree with him. It really is a shame that the tours have to stop because of fear. Very sad commentary on the world we live in. I never thought I would ever read a thread that had both sugaring and terrorism in it.

Maybe Maple Grove will reconsider after they realize the decision was not good for public relations.

Allright, back to vacuum discussions.

Steve

[802maple]

Unfortunately it really isn't in the hands of Maple Grove. You would be surprised to see what some corporate buyers have walked away from because they didn't like it. I have witnessed huge buyers walk away because they didn't like what they saw at some of the sugarhouses that supplied Maple Grove, They had no problem with Maple Grove themselves, but didn't like the cleanliness of the producer and that producer would put most sugarhouses to shame as far as that goes.

[farmall h]

802, the article in the paper stated that the corporate buyers were concerned about product tampering during the tours. I do agree that there are some nasty sugarhses out there. Mine is more rustic than nasty. I don't have the cement floor, (accept under the arch). No running water (accept from garden hose..which freezes regularly) we do have electricity! I do have all my countertops cleaned daily and all pails are taken to the milkroom for cleaning. I agree, if the USDA treated sugaring like they do dairy farming alot of us would have to make the big change...me included. Good point.

[220 maple]

Mapleflats,
I hope your kidding about the Chinese planting Sugar maples? They planted apple trees years ago and now they are wrecking the apple market in the good old US of A. I'm hoping they don't have the right weather patterns for syrup making, otherwise they will wreck the syrup market for the exporter.
Now as far as Dr. Perkins statement about getting prepared to make even more syrup. The sooner the better. I need more West Virginia Syrup. The toursit demand it and I can't make enough. About ever syrupmaker I have talked to in West Virginia can't make enough. More customers than product.
That is one of the advantages of being on the fringe of the Maple Production area of the Country

Mark 220 Maple

[maple flats]

No, I am not kidding. I read it some place but don't remember where.
I also need more syrup, I sell out early every year and I am not on the fringe of syrup country. There are several producers within 25 miles of me and I have sold out at retail every year . 2005 was my last year I had any carry over. By the way, my prices were not give away either, for example, I got $54/gal, $32/half gal and $17/qt in plastic this year.
By the way, at the NYS Woodsmans last weekend, there was a producer who was selling grade A Lt, Med and Dark at $37/gal. I did not buy any to see if it was any good but did try a piece of molded sugar and it was good. I tried to tell him he was way too low price but he wouldn't listen. He sells bulk in 30 gal bls at $2/lb. He is out of Crogan, NY. I wonder how much he pays for the booth space (inside booth) to sell it that cheap. I told him he could get at least 2.40# and sell everything he wanted and make more with no bottling costs. He was not impressed.

[Thompson's Tree Farm]

Dave,
These guys floor me. I sold my bulk syrup near Croghan and got 2.29/lb for C. Got $3 for light and 2.90 for medium. Do they take the first offer that comes along? I'm in the same boat of being sold out (well 1 gallon left) Sold half again this year over what I did last. Shoulda kept another 55 gallon drum of light and one of Medium....20-20 hindsight:rolleyes:

[maple flats]

I spoke with the guy at the last 3 maybe 4 Woodsman's shows. He is not interested in trying to sell for more. I might buy some of his product next year to taste and determine if it is good. He claims he has over 3000 taps, all on vacuum and he sells his syrup at slightly under his neighbors to move it. He implied it was all his product. He had gal in plastic but only has 1/2 and qts in tin, I was going to get a qt just to test it but I do not like tin, it seems to impart a metalic taste to the syrup.

[bison1973]

You can bet the MAPLE EQUIPMENT manufacturers ARE hoping China is planting sugar maples.

[mapleack]

You can bet the MAPLE EQUIPMENT manufacturers ARE hoping China is planting sugar maples.

Probably not, the chinese would ignore the patents and copy all the equipment.

[bison1973]

So I guess aq equipment companies (like John Deere) only sell their products in the USA and Canada?

[Mark]

I thought China tried to plant maples but the longhorn beetle took care of them

[TF Maple]

according to this article they have their own maple trees and they are destroying them with all the construction going on. http://www.gardeningcentral.org/chinese_maple_tree/chinese_maple_tree.html

[Mark]

Looks like a different tree to me.