Is any R.O. suitable for sap?

[cjf12]

I am sure this has been hit on already but haven't found it.

I have been looking on eBay at commercial R.O.s. Will any type do the work we want it to, or do I need to look for something specific. Seems prices can be cheaper than suppliers for maple for same output. But am I comparing apples to apples? New to this area but wouldn't mind getting one in the future.

[madmapler]

Maple RO'S have recirculation pumps to keep the sugars from plugging up the membranes too soon. Some of the small ro's (4"membrane)don't though. You can use them and you might even add a recirculation loop like some older RO's, but they won't be as efficient as maple designed RO's. You would probably need to at least change the membrane. What size are you looking for?

[maple flats]

There are lower priced maple RO's than what the big guys offer. Check out Ray Gingerich, H2O, NextGen and MES to mention a few. I have a Ray Gingerich 250 and it performs well. Mine does about 250 gph and can remove as much as up to 75% of the water in 1 pass. It seems to flow much faster and do even better trying to get a little under 75% out in one pass and then run a second pass. Mine does not have a recirculation pump but it has a rather effective recirculation loop where I open a needle valve that allows a portion of the concentrate to loop back to the high pressure pump inlet and go thru again.
I bought it back in 2011 and it cost $3200 then. I do not know what they are now.
Since I got mine there are a few producing well made smaller units, many built on a dolly or hand cart. NextGen makes som real nice looking well designed ones in the 75-I think 200 GPH range, all on hand carts as do others.
The issue with using a non maple RO for maple is that there are several things that are different. I you use one made for water purification they are usually too slow for maple and they are designed to get water. They keep the water (permeate) and we keep the concentrate while they send that to drain. The membranes are also quite different. As RO's for maple evolved the membranes for that purpose got much better at removing water (permeate) from the sap.

[Ghs57]

There's a local shop here carrying NextGen, and I have some literature on them, but haven't read through it all yet. The small units seem to be reasonably priced for us small guys, at around $2K. They are as Dave said, hand truck mounted with no frills. I'm looking to expand next year, and if I do, I want an RO simply for efficiency with my current rig.

[BreezyHill]

More like oranges and clementines. LOL

You can build your own unit from parts on ebay and save big $$$ if you are at all mechanically inclined.

I have an old Memtec RO that was built for maple and was new in 1982. The tech back then was high pressure to squeeze the permeate thru a membrane ( brane).

With todays branes you do not need that high pressure of 500 psi but only 100 will do the job and the ability to go higher can be used when the brane starts to load up.

My problem is with a pair of 4"x40" xle branes my pupm has to much volume for the branes in series. So I need to have them parallel and split the flow of the pump to not pass sugar. So this summer I will be building a brane cart to have a total of 4 branes. there will be two pairs of 2 branes in series.

Running in series increases your sugar content by removing more water from the sap in the second membrane.

The other thing is when you wash the branes to remove the calcium and other minerals and any sugar clogging them you need them to all be parallel...if they are still in series what you wash out of #1 you tend to deposit into #2. This shortens the life of the branes as the more you wash them the life span of the brane is shortened. Not washing them enough also will reduce their life span as they loose efficiency.

You can build into the system a recirulation loop to get an even higher concentration of sugar from the system. I am not going to build this into my sytem to start unless I find I have the time but I am planning to design it so that I can add a procon pump to the system to get the most capacity out of the build.

I have a 2x6 rig and have been doing 800 taps on 28+ inches of vac and it is far more efficient than running the rig for 18 hours to [U]try[U] and stay ahead of the sap.

I was sidelined for this season by a drunk driver that broke my back and a TBI. This is the second time our family operation has been idle on the farm since 1971. Winter of 2010 my dad passed and we didn't have time with 3 sons, a farm and feed mill to do sugar. 2012 the middle son twist my arm to fire back up.

The RO is the work horse of the operation. So it is getting a turbo charger! I also plan to switch the Rig from wood to oil fired. Don't have the time or ability to boil til 1 am right now and with a well setup burner I can add more efficiency to the rig and be able to be boiling a little faster and be able to shut off the burner and be finished.

I do highly recommend a few toys to add to your RO that a DIY system usually doesn't have.
I have 4 float gauges, Membrane Circulation...tells you the flow to the branes...to high and you pas sugar
In flow rate...tells you how much you are taking from the feeder tank.
Concentrate out flow...how much sugared water is passing.
permeate out flow...clear water flow.

This help you to adjust the pressure of the unit.
Temp gauge hooked to brane flow rate will help you maximize the wash and rinse cycles and not get to hot for the branes.
Pressure guage is to adjust the unit and to see when the branes are starting to clog.

The last toy/tool is a sap refractometer. They are necessary tools to optimize and fine tune your ro. With this unit you can get all the sugar out of your branes when doing a rinse ycle of them. I can take a reading every 4 seconds if needed. When you first start the rinse of the branes you will be flushing out permeate that has just as much sugar in it as your concentrate had. This will last depending on how clogged your branes were.

I run this rinse or flush water back to my feeder tank. I run it til I get down to 1% if it is dropping rapidly. BY the time I walk the 20 feet to the RO valves the unit will be nearly at 0% One time I ran over 75 gallons of permeate as retained flush water. The concentrate was at 12% sugar and the flushed water tested a little over 5%.

Automatic shut down switches are a very important feature to me. My unit will shut down on high temp, high pressure, low pressure, and leak. I have yet to figure out how the leak unit senses but it works very well. The others will save your pump and or branes from catastrophic failure.

If you decide to build your own unit I strongly suggest building a manifold for unit feed source valves. I have 3 on my unit currently. Wash tank, Rinse/permeate tank, and sap tank. I have to change the lines around when I wash because I have two sap or feeder tanks for the RO.
I batch with my RO to get the sap down to a sugar level I can boil off in 3-4 hours. Problem is that the trees are usually not on my time schedule so there are times that I have to RO my main collection tank into by batch tank that is also 500 gallons and an insulated bulk tank. There have been days that the trees did not watch the same weather report and they have run all night and I have a tank that is over flowing of nearly over the top. So I have to RO the collection tank into itself as the batch tank is also full.

Depending on how many taps you have and how fast you want to have sap to feed the rig is how many branes you run; or you can also do a small batch of sap that will allow firing the rig up and keep adding to the rigs feeder tank as it needs. Thus you have no realized you need to have just as many out let sources as you need to batch and send sap to the feeder tank.

So in my opinion even some of the Maple ROs that are on the market need modification to be a true sap RO; because they will not just drop into the sap house and all you need to do is hook up your hoses and run.

If you are looking for a way to save money in the long run, need to spend less time in the sugar house and more sleeping/ working/ family time; then an RO is in your future.

Ben

[maple flats]

This is how I typically use my RO. When I get to the sugarhouse with a load of sap I usually pump it into one of my sap tanks. I then hook up my RO to run the sap thru and send concentrate to my evaporator. Because my head tank always starts out empty, I start concentrating at a slightly lower pressure, which sends a lower concentrate to the head tank. If my sap is at 2% I often send it to the head tank to begin with at 6 or 7%. As soon as I have 20 gal or so in the head tank I fire up the arch while I continue to send 6 or 7% concentrate to the head tank. When I get to about 70-80 gal in the head tank, I turn the pressure up so I am usually getting about 8% concentrate to the head tank, all the while, I'm using the head tank to feed the pans. When the head tank gets to about 120 gal (I have a 150 gal head tank) I change, by opening one valve and closing another I switch from drawing sap from my sap tank to getting it from my head tank. I then need to back off the pressure some because concentrate is harder to squeeze water out of than sap it. (On sap I run at 270-275 PSI, on concentrate I back off to about 250 PSI and once the pressure stabilizes as concentrate is then being the only thing being pumped thru the RO, I turn the pressure back up to 270 or so) At this 270-275 I am getting more concentrate and less permeate out than I did with sap. I continue to recirculate thru the head tank until it gets down to about 30 gal, at which time I switch back to pulling from the sap tank, all while boiling. Doing it this way my concentration varies thru a boil from a low of 6% up to a max of about 13-14%. To switch it only takes about 2 seconds, I just need to keep an eye on the level in the tank. For that I have a sight tube just where the line enters the sugarhouse that shows the level in the tank that is butted against the north wall on the outside of the sugarhouse.
Having the RO makes it possible for me to go thru 300-325 gal/hr of sap on a 3x8 pan. Without it my best on this rig was 80 GPH. and for that everything had to be ideal or it dropped.