Operating Temperature

[turtlemaple]

We are looking for a used RO machine, roughly in the range of 150-250 gph.

One thing that several dealers have told me is to be cautious about the temperature of the sap. They say that the specifications are based on 77 degrees F, and if you drop to 50 degrees you can expect a 40% drop in efficiency and it goes down hill from there.

Since we by nature operate in the cold, can anyone with experience tell me how their performance is and any precautions they take. I assume most people keep their sap tanks outside, so the sap should be in the 30s and 40s, how does it work at those temperatures?

Any additional tips and tricks would be appreciated.

Thanks,

Paul

[maplwrks]

Paul,
All sugarmakers run their sap through at 35-50 degrees. While it is true that sap goes through the membranes better at a higher temp., it is not advisable to warm sap before processing. A few years ago, a couple of sugarmakers toyed with the idea of warming it through a heat exchanger. The result was high bacteria and dark syrup and plugged membranes. Save yourself a lot of headaches, DON'T DO IT!

[mountainvan]

Paul, my sap temp is usually 35-45 degrees and my ro does 300 gal/hr. It's rated for 250. Keeping the membranes cleaned and rinsed everday is the key, in my humble opinion.

[lew]

Sap temperatures can very a great deal due to a variety of reasons, length of mainlines, color of mainlines, position and or location of tanks, length of time sap sets before being processed, etc. I've gathered sap that was so cold that it was frozen on the surface to sap that was over 80 degrees. When we used to run the old style Filmtec BW membranes(brackish water), temperature affected the output of the RO signicantly. But, we switched several years ago to Filmtecs NF 70 membranes and we no longer have that problem. If my sap is 38 degrees or 75 degrees, my RO still eats 850-900 gallons an hour. Only a very low sugar content will lower these numbers. I should also state that with the old style membranes, you adjusted your machine to a specific pressure and you got what you got as far as production goes(our pressure with the old Coster machines was 500 psi). With the NF membranes, you adjust your machine to certain flow rates so long as you don't exceed 500 psi, and we always get our 850-900 gph.

[Russell Lampron]

My Lapierre RO is rated for 150gph and it has a NF90 membrane. My sap temp is usually in the mid to upper 30's. I can almost set my watch by the amount of sap in the tank to when it will shut off. It is rated at 50 degrees but the lower temps don't seem to affect it much. Hope you can find the machine the you want. You won't be sorry you bought it after you have it.

Russ