Getting to high concentrate percent

[bigtreemaple]

What methods are guys using to get their concentrate to higher percentages over 8%?

[wiam]

I have gone to 12% with my machine in one pass, but it's old.

[Russell Lampron]

I recirculate mine back to my storage tank with high concentrate flow and the highest permeate flow possible. I run my high pressure pump at 200psi and keep recirculating it until I get to the sugar % I want. The closer I get to 20% the better my evaporator likes it. It does take a long time with my small RO though.

[Maple Hobo]

What methods are guys using to get their concentrate to higher percentages over 8%?

Some systems are designed to do that in one pass but have a series of membraines to get high concentrations.
Lapierre sells a rack for multipule or single stand alone membrain vessles with thier own high pressure pump.

I've had our unit at 10 brix once this year.
My wife helped run the RO when I was at work and she had it set really low (only removed 25% water).
So I pumped it back into the raw sap tank and re ran it.

I wouldn't recomend doing this often though, I think its hard on the membrains.
You'll probably need to do a chemical wash after to return to prior flow rates.

[maplwrks]

Russ nailed it---keep your flow rates high and let the machine do it's job,recirculating back into the tank.I do this until I get to 20%, then start boiling.
Hobo is also correct, in that you need to give your membranes a hot water rinse every day. I do a soap wash every other day. This helps keep the flow rates up on your machine

[DrTimPerkins]

A single pass through a membrane is good for about a 4.6% concentration factor, but that can be tough on the membrane. You can either run the membranes in series, or recirculate (but that can warm up the sap a lot) to get to higher concentrations. To get higher throughput, you run the membranes in parallel.

[PATheron]

Another thing you can do thats easy on the memranes and might heat the sap less is pass it once open flow to a tank. The ro will perform real well with big flow rates and if its a one post machine youll get probly 4% open flow and if its a two membrane machine youll get six % both numbers assuming starting with 2% sap. Once youve got that you can feed it to the ro and youll get really big numbers when you run it at the normall concentrate output flow rate. I take two two post machines and run them each at 4 gallons a minute say of cocentrate and make roughly 7% then after I have a good bit of that built up then I take one machine and sent it to the head tank at 2.5 gallons per minute at 15% and keep the other one still passing it from the first tank to the second tank or take both machines and then I can send both ones at 5 gallons per minute of 15 % and start boiling in just a little while whatever the situation lends itself to. Theron

[bigtreemaple]

So what I think I have heard is that if recirculating to the raw sap tank, or to a secondary concentrate tank, the plan should be to not push the pressure too high and not try for high concentrations in one pass, this keep the flow rates high without straining the membrane, correct? And keep an eye on the concentrate temperature.

[Greenwich Maple Man]

Alot depends on the machine. Lap. says a single post machine is capable of taking 2% sap to 8 or 10 on one pass without damaging it at all. I don't know what the other companys say. Everybody I know runs there sap to 8 or 10 in one pass with no problems and have done it for many years. Keeping up on you washing and rinses is key to proper maintnance.

[Mathieu]

The quality of the recirculation pumps and the type of membrane in columns make big difference between an RO able to keep his flow at high brix without issues and another one plug his membranes at the same concentration.