GE Merlin RO for sap???

[Brent]

I've been reading the specs on the new GE Merlin RO thinking it would be pretty good for sap ... and very inexpensive.

At less than $ 400 on the net the specs are

- 1/2 to 1 gpm permeate at 77 degrees and 40 to 80 PSI feed pressure YES PER MINUTE

-at 40 degrees F and 80 psi the permeate flow is 0.7 gpm

If that stands with sap you could get rid of 0.7gph x 60min x 24hrs = 1008 gallons every 24 hours.
That sure would make a huge dint in the boil time for a small operation.

I have not yet got a price for a pump / regulator that would put out 80 psi but I think you'd have a lot of change left from $ 1000
for the whole system.

Here's a link to the GE Web site where you can check the details, including a full User's Manual
http://www.gewater.com/residential/home/merlin.jsp

And at $ 100 for a new membrane it wouldn't break the bank if it only lasted one season.
(Edit: just reading the manual ... it takes 2 membranes. ) The factory claims a 3 year average life for the membrane.
Surely it would last us 10 - 15 days on sap eh! ( Canadian )

Does this look like it's worth a try ??

Anyone got a lead on where to get a pump that will give 4 GPM at 80psi.

[WESTVIRGINIAMAPLER]

Pretty interesting, I wish someone would actually try out some of these things instead of just talking about them for the past several years. I don't mean any offense to you Brent or anyone else, but for about as long as the trader has been in existence, this subject has been brought up, but no one ever seems to try one.

[jemsklein]

do you know why i will tell you give me the mony and i will try it
i would try it if i had a $1000 to play with

[maplehound]

I am no expert on Ro's. Howevere when I talk to local water treatment experts and to local plumbers about how we use RO's they just scratch there heads. They way I understand it is that most household RO's don't have a discharge on them other than the drinking water discharge or what we would refere to as purge. What we look for would be the waste water (so to speak) that would come off a household RO. But on the household sized RO's the waste is kept in the membrane. AS I said I am no expert and am not sure if I am corect in this, but is the way I understand it.

[Brent]

The little baby one we have been using for 3 years only gives us 8 gallons of permeate at day. We're still on our first membrane with a well water source.

Both it and the Merlin have a condensate line that would normally go down the drain. For sap this will be saved.

Other than the lower limit of 40 degrees, I see no reason (yet) why it would not work.

[Russell Lampron]

Like royalmaple said in another post on this subject is will the membranes pass sugar? Maple RO's use nano filters and some of those will pass alittle sugar. It would be a shame to spend the money to get one of these and find out that it passes sugar and the correct membranes cant be had. The nano membranes only come in 4"x40" and 8"x60" sizes from what I have researched so far.

Russ

[royalmaple]

I think you will find that those membranes in the household units will be "loose" and not filter at the nano level. I'm not sure, but that is my initial thought. I haven't seen the membranes on these units but if they don't look like they are solid fiberglass then chance is that they are not going to filter out the sugar enough. Might though, just guessing. Very important point to clarify with the manufacturer.

Just give me till after the summer and full line of Royal Flush Ro's (TM)will be on the market, catering to the small producer.

[super sappy]

Matt- Put one on the Farm plan for me. I got about $8.00 down and the rest will follow over the next 20 years.Maybe I can get an RO and take my kids to the dentist.Seriously touugh a reasonabally priced small unit would sell. Good Luck Royal flush is a great name.-SS

[Brent]

Matt
the GE specs says 99% TDS rejection when the pressure is at maximum, ie at 80 psi. It doesn't say 99% sugars excepted.

In any case if it does pass some sugars and ends up being deemed useless for sap, I would replace the 8 Gallon Per Day unit we use in the kitchen today and only be disappointed, not out of pocket the whole cost for nothing.

I seriously doubt there is a "special" membrane for syrup RO units, but life is full of surprises.

I think I'm going to give it a try. First reports should appear here about mid March.

[WESTVIRGINIAMAPLER]

Brent,

I think it would be awesome if you give it a try. Since you already use one in your house, you would have a spare if it didn't work. It would put this subject to rest or cause it to blow wide open if it actually works.

My question would be how you would clean the membrane at the end of the day to get out the bacteria and other foreign substances that the sugr RO's have built into their system to wash and backflush at the end of the day.

[HHM-07]

brent

It seems to me that if these things would work with all the small guys out there they would be all over the place Those are my thoughts

Dick @ hobby Hill Maples
170 taps 2x4 leader
All on line

[Brent]

Brandon

I have never used a big "maple" RO but there are a few ways to attack this.

1) use DE to pre filter all the sap before it hits the storage tank. This should take out 99% of the bacteria.
2) us a UV on the filtered sap, that is now very clear and the UV should be very effective on, to kill whatever you can and leave it running in the cycle that feeds the RO
3) GE offer a tank on the system as an option that collects a bit of permeate, and I mean a bit, I think only one or two gallons. When demand stops in normal kitchen use, it fills the reserve tank with permeate then shuttles a valve to flush the membrane with this permeate, then with some of this permeate still sitting on the membrane, it shuts everything down. With minimum sugar now on the membrane, very little bacteria should grow. They do it to prevent dissolved solids from migrating through the membrane when it has no operating pressure on it. They say membrane is 99% effective at 80 psi and only 90% effective at 40 psi so you can see the door opening to regular osmosis as the pressure drops. So they surround the membrane with water that has virtually nothing in it.
4) just like the big guys, collect a LOT of permeate and flush the H%*& out of it. For the huge difference in price you do not get an automatic system. You would have to switch around a few hoses or valves.

* this is the way I see it working now. Like I said above, life is full of surprises. We'll see.

[WESTVIRGINIAMAPLER]

Brent,

I hope you are right and I hope it works well. Give it a try and let us know. Do you have a sap hydrometer to test both flows??

[Brent]

Yup, got the sap hydrometer. With any luck it should be so low I can't read it.
I was actually planning to boil down some of the permeate to see how much sugar is getting through. Also been wondering if another quicker and easier test could be done. Diabetic sticks or ??????????

[gmcooper]

Matt, When you get into production you might want to rethink that name. There is a company near us "Royal Flush" they rent those little poly sheds with a seat in them!!!!! It would not be good for your business to get confused with thier business. LOL
Mark

[Russell Lampron]

Brent a refractometer would tell you instantly if there is any sugar in the permeate. That how I check mine to make sure that my membrane isn't passing sugar.

Russ

[NH Maplemaker]

Russ, you were talking about a Dr Cluff who owns Clear Water sytems out in Tucson, Arizona last year! I was just on his site. His systens look like they would work real well for smaller producers!! The CWP SW-100 will do 2000 Gal a day,thats 83 GPH. with a 4"x40" 5 micron filter and a 160 PSI pump. That would work for alot of small producers. They may half to turn it on a few hour before boiling, but most would'nt be able to catch up after it got started for 2 hours. Then he has larger system also. What do you think? Maplemaker

[Brent]

Brent a refractometer would tell you instantly if there is any sugar in the permeate. That how I check mine to make sure that my membrane isn't passing sugar.

Russ

thanks for that idea ... I'll see if my honey refractometer will calibrate to near zero. Just looked at your pictures. We're going to have almost identical set ups except you'll have a real RO.

I've got a Pfaneuf 2x6 with hoods and preheater on order. Even our shacks are about the same size.

[Brent]

Wow this is starting to come together. One of the makers of the coolant pumps we use on the CNC machines we sell also makes a stainless pump with an inverter drive that automatically senses the pressure varies the rpm to give constant pressure up to 140 PSI.
Absolutely perfect.
A regular pump with a pressure relief valve will do a lot of thrashing pumping and by-passing, wasting energy and heating the sap ... when we want to keep it cool and no cavitation froth. This one will have no wasted energy.

[802maple]

I will be very interested to see if this will work. There are membranes specifically made for maple although several others can be used. If you are permeating about a gallon a minute then you will most likely be making less than a quart a minute of concentrate. Good luck

[NH Maplemaker]

The clear water RO's use nano filters as was stated that maple RO's use and they also come in larger sizes than the CWP SW-100. The CWP 400 is an 8000 GAL a day RO which is around 300 gal an hour unit! It sell for $5,750. I guess I need to call them and ask them these questions!

[Brent]

802

the catalog /manual says it needs a feed of 4 GPM

if roughly 1 GPM is permeate then 3 GPM is concentrate

so we are only reducing the water content by 25% on each pass.

I was planning to start it up and let it continue re-cycling to get up to
8 to 12% sugar like the big machines. In any case every hour it runs saves about 1 hour of boiling in a 2x6 evap. That will be a lot of hours over the run and a lot of firewood I don't have to cut dry store and move.

I'm almost as excited about this as the new evap.

[Brent]

Does anyone know if there really are special membranes for sap or are they just telling us that to keep us coming back.

[royalmaple]

Get a 0-10 sap hydrometer to test your permeate.

Mark no need to be confused with some other Sh&ty business.

This unit might work and if it does that is great. And like you said you have a use for it regardless so give it a try for sure. It would be nice to see if it works. There are many different styles of membranes on the market for various levels of purification, that's why I mentioned the nano filtration. This unit might have the right membrane to do the job. I just didn't want you to think that since it was an RO, that it would concentrate sap by stopping sugar molecules automatically. It may, and I hope it does. Keep us posted.

[royalmaple]

There definately are specific membranes used for sap concentration.

Not to say that there are not other alternatives, because there certainly is. But there are specially formulated membranes for just concentrating sap.

[Homestead Maple]

Brent,
Dow Chemical Co. makes a lot of the membranes for RO's and their brand is Filmtec. The smallest Filmtec membrane you can buy for an RO for maple sap concentration measures 8 inches in diameter and is 40 inches long. Referred to as an 8x40. This membrane is called the MarkI and was specifically designed for sap concentration. These are used in the larger RO's, starting at 500gph and going up from there. Dow makes smaller membranes that are used for the water industry and these smaller membranes are used in the smaller RO machines only because that is what is available. They are very efficient for sap concentration but not quite as good as the MarkI. I contacted Dow when I was thinking of buying an RO because I was going to buy a 300gph machine and asked the Dow rep if there were any plans by Dow to make the MarkI series in a smaller size, say a 6x20, or a 6x40, and they said no. they said that the N series of the Filmtec was efficient enough for those size RO's for sap concentration. If you ask a RO manufacturer what they use in their smaller RO's, (80, 160, 300gph, etc.) machines, they will tell you they use the Filmtec N series or something comparable.

[Brent]

I had a look at the Dow site and then went back to the GE site to try to get something that would allow a comparison. Not enough data that I could understand and compare.

If the Merlin allowed 5% of the sugar to pass and the Dow maple membrane cut that to almost zero, I still think the gain in boil time would be worth the trade off. But that's all just speculation.

I think the time and wood saving possible are so huge for a small producer that I'm going to give it a try.

[802maple]

I don't know what will happen honestly with a small unit like that as I have never used one with water or anything else for that matter, that is why we need someone like yourself to step out on the limb and try it out and report back. On the other hand I have had some experience with the larger r.o.'s that we use both in making product and as a service tech on them. I have to believe that they will clog quite fast with sap compared to water as it will be impossible to make sap "clear" even with a uv light and ultra filtration. But as I said go ahead and try because I will be the first to say that this is how we find things out by experimenting. I certainly am not going try to discourage any innovation that can be made for the little guy.

[gmcooper]

Brent,
I'm all for someone to give it a try.

Maybe my math is off but from your post the Merlin will allow 5% of sugar to pass thru that means 13.4% of your syrup production is gone before you boil.

Syrup 67% sugar, with 5% of your sugar wasted .67/.05= 13.4%

43 gallons of 2% sap would normally produce 1 galllon syrup. Now that 43 gallons of 2% sap will only yield .864 gallons syrup.

Maybe that much sugar will not pass thru?
Mark

[Brent]

You guys are all so wonderful.

Everyone is encouraging me to try it ... spend my money

Nobody STATED that the loss was 5%. I was just speculating.

Why would you put syrup through it at 67% ?? I thought the whole idea was to reduce the water content of sap.

And who knows, if it rejects sugars at the same ratio as they claim for all other dissolved solids it will only loose 1%.
They (GE) claim 1% maximum migration of dissolved solids when run at 80 psi.
1% loss of a 2% solution is almost unmeasurable.

Check my logic. (high school math was a lot of years ago)
stat with 1000 gallons of sap at 2%
pass through the RO once and you'd have 750 gallons left.
pass through the RO a second time and you're down to 562 gallons
pass through the Ro a 3rd time = 421
pass through a 4th time = 316 gallons of sap

How long would it take:
pumping 4 gallons per minute as per GE's spec
1000 gallons / 4GPM = 250 minutes
second pass 750 gallons / 4 = 187
third pass 562 gallons / 4 = 140
4th pass 421 gallons / 4 = 105 minutes

Total time for 4 passes 682 minutes or 11.36 hours.

OK now lets see if I can calculate what happened to the sugar content
each time you go through you MIGHT loss about 1% of what was left
start with a 2% solution - 1% of that = 1.98%
the concentration is now up by 1/3 so 1.98 x 1.33 = 2.64%

second time lose 1% of 2.64% would cost knock you down to 2.61% but you are less water too so your concentration is now
3.47%

the 3rd time through lose 1% of 3.48% and with less water the concentration goes up to 4.58%

the 4th time through lose 1% of 4.6% and with less water the concentration goes up to 6.12%

the cost of running the 1/2 Hp pump would be maybe 25 cents for 11 hours.

Overnight the 1000 gallons you started with has become 316 gallons

On a 2 x 6 evap at 40 gallons an hour your have gone from 25 hours boiling to 8 hours.

To confirm the math on the sugar loss think of it this way.
1000 gallons of sap has 2% or 20 gallons of sugar
first pass loss is 1% of 20 gallons and you're left 19.8 gallons of sugar
second pass loss is 1% of 19.8 and you're left with 19.6 gallons
third pass loss is 1% of 19.6 and you're left with 19.4 gallons
fourth pass loss is 1% of 19.4 gallons and you're left with 19.2

That to me is a great trade off save 17 hours of boiling and lose only 0.8 gallons of sap
which I think would roughly make 1 gallon on syrup.

Furthermore the REAL sap RO units have losses too. I have not been able to find, even on the DOW sight that makes
the sap membrane, any claim to their losses. Since the pass through rate is much higher, I would not be at all
surprised if the single pass loss was not more than this baby GE unit.
The big "potential" difference is that we have passed through 4 times vs. their once.

But THEY cost $ 7500 and I'm thinking I can make one for less than $ 1000. I'll be using a
variable speed pump with a gentle start and they use 2 pumps to create the gentle start.

I'm sure there's a lot more to this to be worked out.

Anyone out there got a spec sheet for a big RO that gives the loss rates.

[gmcooper]

Brent,

Maybe I should have explained it differently.

If the membrane allows 5% of the sugar in the sap to pass thru that is much more than just loosing 5% of your sap.

The math was to show how you are actually going to loose 13.4% of your potential finished syrup if you loose 5% of your sugar in the RO before you ever boil.
Nothing about putting syrup thru an RO.

[Brent]

To turn the arguments I made above all around the other way

would you boil 17 hours for 1 gallon of syrup ????

Not me

[802maple]

The only membrane that I know of that sometimes will pass sugar is the nf270 all others on the start up will lose a small amount after that they close in. My argument is not on whether it will pass sugar. I think you should try it and I am not saying it to just to spend your money. You said that you could justify it because you could use a updated water system. And if you found something that would be a good thing. I have designed a few things and tried them out and some worked and some didn't. If I had the time and was as convinced as you are that it would work I would certainly try it. If it. was to work, maybe next year at this time you will be making the modifications to these units and selling them faster then you can build them. Certainly running only 80 psi should make them last longer as the larger r.o.'s mostly operate between 200 and 500 psi.

I say with all sincerity, GIT-R-DONE

[Brent]

if it works as well as I hope, I'll package us the varispeed motor and RO and offer it to guys on the Trader list. A source for the constant pressure pump is not so easy to find and I think we have a perfect match for what the RO needs.

[WMF]

Brent, The membranes in this machine will not pass any sugar as long as the permeate tube connections are sealed with o-rings. The Problem you will have is that the membrane will be too "tight" and will foul very quickly in a machine like this with minimal recirc flow across the membrane surface. You will not want to have a variable speed pump as you will want all the pressure and corresponding recirc flow you can get.
An RO membrane used for sap needs high recirc flows to keep from fouling and to properly clean it when it does foul. You should get on some membrane sites and look at how spiral wound membranes are constructed before you get to far into this project. Filmtec's site is good along with Hydranautics and Koch fluid systems.

[Gary R]

Brent,
This project sounds interesting. I could see where an affordable RO would be helpful for the small producer. I found a company, APEC, at www.freedrinkingwater.com. Check it out. They have all sizes of RO's. I have started an Email conversation with them. There stuff is for the water industry and I am in the proccess of explaining to them how RO is used in Maple. Hopefully I will find out from them if a modified version of there machines would work for us. Good luck!

[NH Maplemaker]

Her is another web site http://wwwcleanwaterproducts.com/ I think Russ Lampson or Royalmaple post it awhile ago! This company claim they have sold there units to maple producers!

[Brent]

Gary

I just had a quick look at the freedrinkwater site and the only two systems I could see had a flow of about 6 GPH at about 5 or 6 degrees C. This is the temp at which the sap would be process.

The GE Merlin stood out in my search because it will to about 0.7 GP MINUTE or 42 GPH at that temp.

[Brent]

Welchmaple

There are two reasons I wanted the VS pump.
1) the GE specs call for a "gentle" pressurization of the membrane. I think this is why the big systems have two motor. One for start up and one for high pressure high flow.

2) the one I am planning to try has automatic pressure to speed regulation
Preset the pressure to 80 PSI, the max that GE specify and you get it automatically and continuously, regardless of membrane plugging.

From what I have read the big systems have a lower bypass ratio that this one. This small one passes 3 GPM and creates one GPM of permeate. The big ones are just about the reverse of this ratio. Getting a 4:1 concentration
ie 2% to 8%

Keep in mind the big systems sell at 10 X the price.

[Brent]

Maple Maker

I had seen the Cleanwater system as well .

They claim 1000 gallons per day .. about the same as the GE unit and that is at 70 degress. Not our temperatures.

And it costs over $ 3000. and you still need a pump.

I'd love to find one with better specs than the GE unit. HE knows GE does not need our money. But the GE has the best bang for the buck I can see....
if it works.

[WMF]

Brent, do yourself a favor and look at how spiral wound membranes are constructed before you start buying parts. They are all constructed the same way and you need to understand the terms the industry uses. Until you know what the difference between recirc flow and the applied pressure is you are at a huge disadvantage if you want to make a homemade RO for sap.

[Brent]

welchmaple

Can you direct me to some sources to find this information ??

[Gary R]

Brent, the site I mentioned has light industrial units that would probably get the flow you are looking for. They make upto huge desalination RO's and had some good technical stuff on there also. A question. Whats the first thing you are going to do with the sap after it comes out of the RO? Heat it? What if you heated it first to improve you GPH. UV sterilizer might also be needed to reduce bacteria growth. Hopefully I will here back from them again. It would be good to speak to people who build them. Keep up the good work! Persistance pays off.

[Brent]

Gary

thanks for the info.

Actually as the thinking goes on with this project, the ideas keep changing.
I have to re-calculate the big mess above because the unit is more efficient than I understood. It is 33% not 25% as I used in the calculations.
ie 3 gallons feed, 1 gallon permeate, 2 gallons concentrate. Better by a lot.

Furthermore the pump unit I plan to try is big enough to support 3 of these RO units and since the pump is more expensive than the RO, the bang for your buck gets much better with 3 RO's in the set up.

To be continued.

[Jim Brown]

I sure wish you guys would have had this all figured out before I went and spent a load of cash on a new RO this season! LOL

Jim

[Brent]

I re-read the tech info on the Merlin RO last night and realized that it is more efficient than I had used in the calculations I did above. So here goes again

And who knows, if it rejects sugars at the same ratio as they claim for all other dissolved solids it will only loose 1%.
They (GE) claim 1% maximum migration of dissolved solids when run at 80 psi.
1% loss of a 2% solution is almost unmeasurable.

Check my logic. (high school math was a lot of years ago)
stat with 1000 gallons of sap at 2%
pass through the RO once and you'd have 666 gallons left.
pass through the RO a second time and you're down to 443 gallons
pass through the Ro a 3rd time = 295
pass through a 4th time = 196 gallons of sap

How long would it take:
pumping 3 gallons per minute as per GE's spec
1000 gallons / 3 GPM = 333 minutes
second pass 666 gallons / 3 = 222
third pass 443 gallons / 3 = 147
4th pass 295 gallons / 3 = 98 minutes

Total time for 4 passes 800 minutes or 13.3 hours.

OK now lets see if I can calculate what happened to the sugar content
each time you go through you MIGHT loss about 1% of what was left
start with a 2% solution - 1% of that = 1.98%
the concentration is now up by 50% so 1.98 x 1.5 = 2.97%

second time lose 1% of 2.97% would cost knock you down to 2.94% but you are less water too so your concentration is now
4.4%

the 3rd time through lose 1% of 4.4% and with less water the concentration goes up to 6.6%

the 4th time through lose 1% of 6.6% and with less water the concentration goes up to 9.8%

So now we are near the concentration that the big units get on one pass.

the cost of running the 1/2 Hp pump would be maybe 25 cents for 11 hours.

Overnight the 1000 gallons you started with has become 195 gallons

On a 2 x 6 evap at 40 gallons an hour your have gone from 25 hours boiling to just about 5 hours.

To confirm the math on the sugar loss think of it this way.
1000 gallons of sap has 2% or 20 gallons of sugar
first pass loss is 1% of 20 gallons and you're left 19.8 gallons of sugar
second pass loss is 1% of 19.8 and you're left with 19.6 gallons
third pass loss is 1% of 19.6 and you're left with 19.4 gallons
fourth pass loss is 1% of 19.4 gallons and you're left with 19.2

That to me is a great trade off save 20 hours of boiling and lose only 0.8 gallons of sap
which I think would roughly make 1 gallon on syrup.

Furthermore the REAL sap RO units have losses too. I have not been able to find, even on the DOW sight that makes
the sap membrane, any claim to their losses. Since the pass through rate is much higher, I would not be at all
surprised if the single pass loss was not more than this baby GE unit.
The big "potential" difference is that we have passed through 4 times vs. their once.

But THEY cost $ 7500 and I'm thinking I can make one for less than $ 1000. I'll be using a variable speed pump with a gentle start and constant pressure of 80 psi and they use 2 or 3 pumps to create the gentle start.

Furhter more I can run 3 sets of these RO's from the one pump and get similar results a whole lot faster, while only adding 2 x $400 to the cost. ( plus a bit of hose etc)

I'm sure there's STILL a lot more to this to be worked out.

Anyone out there got a spec sheet for a big RO that gives the loss rates.

[Breezy Lane Sugarworks]

The way I understand it is that a maple membrane in good condition(taken care of right) shouldn't lose any sugar. as they get older or not washed right, I've heard of them passing sugar. I could be wrong though.

[Brent]

There ain't no such thing as a 100% rejection membrane. They all let a little bit through. The GE membrane lets through nearly 10% of dissolved solids at 40 PSI and only 1% at 80 PSI. It does not seem logical but that's the way they work.

The best salt water unit I ever found still had a tiny bit of salt that I could taste.

[Breezy Lane Sugarworks]

If I can remember molecule size right, a salt molecule will fit through a smaller hole than a sugar molecule, therefor if the if the membrane pores are slightly smaller than a sugar molecule, then a salt molecule will still pass but no sugars will. Maybe not all membranes are like this but that is how I thought they worked. But even a salt molecule shouldn't fit through a good maple membrane because the permeate should be "pure." Right? But give it shot though. The only way we'll know is if you do it and maybe you'll have a new innovation for the hobby guy.

[Breezy Lane Sugarworks]

Also to go with that thought. You said that going from 40 to 80 psi you go from 10 to 1 % passing through. 802Maple previously stated that the larger RO's tend to run between 200 and 500psi. but the higher the pressure also makes their life shorter if not cleaned right. So if you do make one, these little units might be good for a hobby guy that can't afford a "maple" manufactured unit.

[802maple]

When we test for sugar passage we take 20 parts of permeate and evaporate down to 1 part and if the mark 1 has any sugar passing it will show. Most sugarmakers prefer to not use the Mark 1 as it is slower than the other membranes that are most popular such as the270 as it sometimes is as much as 15% faster. Again this is not my concern. I just think that sap will plug it quite fast. The only way to find out is try it. On paper alot of things have worked only to find flaws in it when applied to reality and vice versa.

[Brent]

The idea that a membrane will get "plugged" does not fit with my impressions of how they work. I used to think they were like filters and junk you didn't want sat on the surface while the pure water went through. But I don't believe that is the real case. The dissolved solids simply remain in solution, floating about until flushed in the concentrate.

The bottom line is, we won't know till after about 4 days into the run. I'm about as excited about trying this as I am in getting my new evaporator from Patrick Phaneuf.

[802maple]

You are correct about the dissolved solids but not the bacteria that imbeds it self in the layers of polymer that make up a membrane. There is no such thing as totally bacteria free sap and that is what will plug a membrane, there is much more bacteria from sap just because of the sugar than what is in water even after going thru a uv light. Every time sap is recirculated thru the membrane you don't only concentrate the sugar you also concentrate the bacteria, which in turn will make it grow faster. I do know this because if you read below you will see that I have boiled 24% sap and I have had to run this sap thru the larger r.o. atleast 3 times to achieve this and even with recirculation pumps I have to hot rinse and followed by 25 minute cold rinse to be able to do this even with the 2- 1800 gallon an hour machines.

I will end this from my end until I hear the results of your test. Good luck and full speed ahead.

[Brent]

Now they're heavy duty RO's

I was planning to put the sap through a DE filter then a UV before it hits the storage tanks, and then keep the UV in the circuit while doing the RO.

These things have tiny surface area compared to your so whatever is left in solids will gum them up. We'll see. It's not a huge gamble in any case.

Update Jan 23:

I have 2 of the GE RO systems on order and the vari-speed pump is on its way. The pump will run 2 and maybe 3 of the RO units. I hope to have it all together for a test run in about 10 days. I have some fructose left over that the bees won't eat so I'm thinking of making up a 2% solution of the to give it a try before the run starts here.

[Brent]

Well I got the Ge Merlin in today.

For comparison, the GE tank type units at Home depot have a single membrane that is about 1 1/2" diameter x 10" long.

The Merlin model has 2 membranes, 3" diameter and 18" long.

This looks encouraging. Pump might get here this week. I'm itchin' to try it.

[jemsklein]

let us know how it works

[Gary R]

FYI, I did hear back from EPCO, freedrinkingwater. They have a technical person seeing if one of their compact commercial units can be modified for maple sap. They understand our uniqueness and are looking to put a 4X40 sap membrane from filtec on it. I'll let everyone know what they say.

[Brent]

when I got the unit home I measured it and it is 3" x 18". Two of them in each system gives me 3" x 36" .

Getting close to the 4" x 40" of the "real" systems.

At $ 400. I think this is a bargain. In fact you could get it cheaper if you found a distributor that sells the kit that does not have the countertop spigot.

( edit .... if it works. )

edit 2: Feb 2nd

Courier is going to deliver the pump Monday morning ... gotta drill some holes and get enough sap to do an initial test
If the trees don't cooperate I may try with some Fructose syrup from the bees. Dilute to 2% and see what happens.

[Gary in NH]

Brent,

The membranes used in the GE system are "low energy tap water" membranes. They are actually "tighter" than a nano-filtration membrane. Nano-filtration membranes remove down to a molecular weight of 160 to 170, or 7 Angstroms, or 10 to the -.35 micron range. This is sufficient for sugars. Even though they are all classified as RO membranes the nano-filter membranes are really "nano-filters". The true RO membrane has the tightest or most filtration capability. It goes down to around 100 on molecular weight, or slightly above 1 Angstrom, or 10 to the -.40 micron range. The true RO membrane operates in a more absolute range for effective removal of metal ions, aqueous salts, and atomic radii. The extra filtration capability is not required for sap applications so nano-filters are used. The nano-filter membrane pores are a little larger so it lets more water through to the permeate side of the membrane while still holding back the sugars. This allows for higher production when compared to a reverse osmosis membrane. It also reduces the tendency for membrane fouling. As the sap is processed whatever was in it to start (other than water) will be concentrated 4 to 7 times depending on the recevery rate of the RO system. Nano-filters will remove some metal ions and aqueous salts but not down to the atomic level of a reverse osmosis membrane. I used tap water membranes in the RO system I designed. I get a slight sugar passage - in the .10% range measured with my sap hydrometer when I process my sap to a concentration level of 8.0% sugar. I am making a couple of modifications to my system this year to see if I can get a higher concentration. I talked with Bruce at Bascom's Maple in Alstead NH and they run their RO's up to 14% sugar. Good luck with your RO project.

Gary

[Brent]

Thanks for all that Gary. I may border on the 'more than you ever wanted to
know'

If the membranes foul in one season and I have to trash them, I'm out $200.
About the price of a cord of wood. If they cut my boiling time in half and wood use in half, I'm a happy camper. I'll willingly trade the price.

I'm increasing my boiling with a new evap and increasing the taps a lot AND hoping to reduce the days in the sugar shack ( back to the day job once in a while )

It may not be ideal but for the cost, it's worth a roll of dice.

[Gary R]

Gary in NH, would you be willing to share your design?

[Brent]

If it works I'll share the whole thing with pictures

If it flops, well .....

[Gary in NH]

Gary in NH, would you be willing to share your design?


Yes, I will get some pictures onto photobucket and give details here. It mat take a couple of days though.

Gary

[Stephen Childs]

I tested a GE Merlin RO this spring to see what one would do for a smaller maple producer. It worked great except the rated capacity dropped substantially when running sap vs. running water. Instead of a permeate flow of 20 gallons per hour, with sap I was getting between 3 and 5 gallons per hour depending on the sugar concentration of the sap. I used a flow control value and flow meter to monitor concentrate but even at the most limited concentrate flow rates I could only get the sugar content up to 5% at 60 psi. It cut my boiling time in half and saved about half the wood in my back yard with 30 taps but I was hoping it would be more effective for producers in the 100 to 150 tap size.

[brookledge]

I'm wondering if it will slow down any more as the membrane ages. But I'd bet that if you are running a pump to maintain 60psi it's got to cost more energy than you are saving or close to it.
I can see why you where disapointed. it sounded like it was a good idea back when the post first started
Keith

[Grade "A"]

Brent was saying that he was taking out around 9 gallons of water a hour out of one RO, he has two so he was taking out 18 gallons total. But he had his pump set at 80 psi. 20 psi more may not sound like alot but it could make a big difference on gph.

[Gary R]

Stephen,

Maybe PM Brent and compare notes. It seems like he did a lot of work with his Merlin's this sping. Do you have detail's on the pump's and everything else you used? Sap temperature I think is also a big reason for reduced output. I would also be concerned about cleaning and live time of membranes. But just think about the potential! A hobbyist could more than double the amount of taps for maybe $1000. That sure beats buying a bigger evaporator for $5000 and up.

Gary

PS, I wish I would have attended your maple confections workshop in PA. I heard from some attendees it was great!

[royalmaple]

Is it possible to control the Concentrate output on these machines?

If so, instead of cranking it down to see how sweet you can get it right out of the RO, open up the concentrate valve and don't try to get it in one pass. Take the concentrate and divert it back into your raw sap tank and let that run for a while. You're still removing water each minute the machine is running. Even though it might seem like your defeating the purpose. Then when the entire batch is sweet enough, run it through one more if you like what you are getting for concentrate, and send that to your head tank on the final pass. Allowing more flow from the concentrate will keep the membrane "open" much longer during your concentration cycle. I'm quite familiar with what it takes when you don't have recirculation. You can get there but takes a little ingenuity.

Without recirculation on the membranes your production will be much lower than if you had recirculation on the membranes. I don't mean recirculating the sap like I described above. I mean an actual recirculation pump attached to the membrane itself.

[Grade "A"]

I am going to try the Merlins this year. I hooking it up like royalmaple said, puting the concentrate back into my raw sap tank. It would be nice to have 8%-10% sap coming out to boil but with these ro's I don't think you can. I look at it as any water taking out is time and money saved.

[Stephen Childs]

I tried a number of things when I was testing out the merlin. My first goal was to remove as much water as possible. I obained the most water removal when I ran straight sap and didn't restrict the concentrate flow. When operating this way I was removing between 4.5 and 4.8 gallons of water per hour but when doing it this way my sugar content would only go from about 2.2 in the source sap to 3 to 3.5 in the concentrate. If I ran the concentrate back in with the source sap and recycled it, as the source sap sugar concentration increased over time the water removal rate would decrease. This was not a problem at the speed I boil (pretty slow in my restaurant pan), it just took longer to get more water out. My second goal was to have the sap as sweet as possible when added to the boiling pan. To accomplish this I had to restrict the concentrate to about 5 gallons per hour but this also slowed the water removal rate to 3 gallons per hour or less. It seemed to work best all around to recycle concentrate back into the sap source tank to get the better of both goals. The book for the Merlin said not to exceed operating pressure of 75 psi, I was using a fairly cheap shallow water pump and it maxed out a 60 psi, to go higher I would need a more expensive pump. I also had a 5 micron filter ahead of the RO that may have killed my pressure some.

[Brent]

Hi Stephen:

Good to see someone else try this little RO. The tech specs show that the highest recommended pressures yield the best rejection of TDS's It's counter intuitive but that's what the specs say. So I ran right up at the top pressure. Drop the pressure 10 PSI and the rejection drops from 99% to 91% (going from memory) So keeping the pressure up is critical. At the 75 -80 psi I had it set to I could not detect any sugars being passed.

I did also play with different temperature fluids and when you get below 45 degrees, or about the range of most of our sap, the permeate production falls off rapidly.

I was really pleased with the results in the beginning. After the second day, I let it go all night recirculating back into the storage tank. I think I got to 12% ( the right number will be in one of the many posts I made about this trial) Made good syrup.

But then things started to get screwed up good and I still have no answer to what caused it. We got a lot of slightly off flavor and really bad sort of metalic aftertaste.
Here are the usual suspects, rounded up, but in no particular order.

1) we were getting to the end of the season and could have mixed good sap with buddy sap.

2) I had put about 30 to 40 hours on the Merlins before I tried cleaning. First with detergent. Flushed them for hours. Everything on both sides of the membrane tasted fresh so I put them back in service. They plugged up quite fast. It could be I did not flush them enough and some after taste came from the detergent.

3) I then went for a long drive and got a real membrane cleaner from a maple supply house. Again I think I used it right and flushed it well, but we had the after taste. See the comments further down about the Xenon membrane in these units. I may have been the wrong treatment completely.

4) At the end of the season I found chunk of wood 14" long x 2" x 2" that I was using to support the preheaters, had fallen into the sap and been boiling there. I think it was maple, but that could have contributed to the bad taste.

5) Finally, I was using a filter press that I had never used before and got suspicious that the metalic after taste was coming from the cast iron filter press plates.

Going to get some new membranes and start over this year.

One important point. GE bought a local Canadian company that developed this low pressure, high passage membrane. It was called Xenon, in Oakville Ontario. By pure co-incidence, we sold them some machine tools. They were extremely secretive about the technology. Most of the time when our service guys where in there, they had a passage to the machine needing service "sheilded" so he could not see anything of how they made the membrane. To further add intrigue, the big systems these guys make are used for municipal water treatements for cities. On the medium sized units they became part of Canada's International Aid team, called DART (Disaster Assistance Response Team). Their specialty was water purification and they were dispatch to Pakistan after the huge earthquake, Indonesia after the Christmas tsunami, after Katrina etc. The point of bringing all this up was that they had a real dust up with the Canadian military on cleaning the membranes. The DART team wanted to be able to clean the big membranes on site and Xenon would not tell them how to do it, insisting ( and making money) by having the membranes returned to the factory. Never heard if anything got resolved. So I have to question if I cleaned them right or if I ever could.
At $ 100 a pop for a new membrane for 30 or so hours of operation, it gets a little expensive. Got to work out how to clean them.

So there are lots of unaswered questions as to why I made off flavour syrup and had to dump half of what we made. I'm going to try again this year. Fingers crossed.

[Elynch77]

Just a guess but concentrate sours pretty quickly since all the microbes get concentrated along with the sap. This can sometimes make things sour or maybe metallic. If you want to avoid this a UV sanitizer on the outflow is a great way to go as studies have shown it improves quality over all. For the flows you are working with you should be able to find a small household one cheap. Most bigger producers don't recirc for this very reason. Then again it could be any number of things.

Ethan

[Brent]

Appreciate the comments Ethan.

You could be right. I did consider adding a UV sterilizer and/or a DE filter.

It was enough months ago now and so many things were at play I may never figure out what it was, unless, it happens again.

One thing I will do for sure is keep my batches smaller and segregated so I don't loose half the year's work.

[maplecrest]

there are alot of factors to making metallic syrup. trees are one. the way you filter your sap is another. yes the filter press is another. was that the first time you used your press? where did you store your filter aid? the aid will cause that. what did you store the syrup in? was it clean? how did it smell? syrup will pick up off flavors due to anything around it. including what you burn in the fire. when washing membranes they open and close. have you checked the ph factor of your membranes. when i am not consentrating i rinse alot to keep the membranes from sugaring up, and do a warm rinse if not a wash every day. springtech says to check the ph level or bench mark the machine to know when to wash it.give leader or d and g a call they can explain it better than i can.

[maple sapper]

Brent,
I have been reading all of your fantastic posts about your test run with the Merlin. I myself was looking for a way to do what you have done. I am quite saddened to see you took all my fun away trying to figure it out. lol. I do have a few questions for you. Keeping in mind some time has gone by and It was a bit fun trying to piece in all the posts from start to finish late on multiple nights once I got the time to read with crossed eyes burning the candle at both ends.

Firstly, I think I understood you were going back to workthis year to refine the timeline for cleaning the membrane? Is that correct? But besides that it did work. Secondly with the pump you choose would that pump maybe support a third ro? Or at that point your better off going to a larger ro unit due to cost of all combined units equaling one large one. Thanks Gregg Kennedy (aka maple sapper)