Duffy's Lane Maple and Honey by Jen and Brent Roberts 15271 Duffy's Lane, Caledon, Ontario |
||
Our new twin GE Merlin Reverse Osmomis System. |
 |
Here are our two GE Merlin Reverse Osmosis units sitting on the floor behind the evaporator.. The Inverter controlled pump that feeds both of them is in the lower left and can be seen better in the picture below. |
||||||||||||||||||||||||||||||||||||
| 2009 Update On the GE Merlin RO systems experiment: last updated Fri April 10/09 We learned of a huge mistake in our use of these last year. The standard residential units come with a carbon pre-filter, that occupies the top level of the three chambers. The RO membranes are in the bottom two levels. This pre-filter is designed to eliminate chlorine from municipal water supplies, and has no use in maple sap treatment. Before the start of the 2009 season, we removed the pre-filters from last year and found them totally fouled. After doing some research on the microbes in maple sap we decided to install a "whole house" style external pre-filter. We used a GE GXWH40L, but any other could be used. We took out the standard filter and got some nominal rated 1 micron wound filters at TSC. Through the course of the season we found these need to be changed about every 48 hours. The microbes have a field day in these filters, which are in the sugar shack and kept warm, like the Merlins, to avoid freezing. We noted that into the second day of nearly continuous running the pressure on both the Merlins dropped from the ideal 80 PSI to 77 or 78 PSI. We did use the adjustable output of the pump to bump it back up to 80, but each time we did we replaced them at the end of day 2 and noted that filtes smelled the distinct smell of the microbes eating the sap. Out Put: Reading the tech lit from GE on these, they run at peak performance when the water temp is up near 80 deg F and the pressure is at 80 PSI. Our sap is typically 40-45 degrees and the performance is way down from optimum. However here is what we did get: With raw sap coming in at 40 degrees, 80 PSI and averaging 2 to 2.4% sugars and clean filters, the system produced 15 gallons of 0% sugar permeate an hour ( filled a 5 US gallon pail in 20 minutes ). Several nights when the temperatures did not go much below freezing, and the feed lines from the storage tanks did not freeze, we left the system running all night. We use 275 gallon beverage totes for storage. After a full night of running these had been reduced to about 125 to 140 gallons of about 5 to 5.4% sap. That cut our boil time for the tank in at least in half and saved that much wood. We did see a considerable drop off of permeate produced when the sap got to the 5 - 5 1/2 % range. So this system is not going to be the way to go for those who and 22% sugar content. The pump we selected is a Walrus TPH2-T6K-SIC. By pure luck this is a manufturer that we know because many of the CNC machining centers we sell and service, come euqipped with Walrus high pressure pumps and we know them to be reliable. We selected this pump because. 1) it hit the optimum pressure for the Merlins, 80 PSI, with a bit to spare 2) it had enough flow at that pressure to feed 2 Merlins ( at least 2, we plan to try adding a third one next year ) 3) it had a soft start with its inverter drive, which could be important in the sugar shack where power is limited. By soft start I mean that the inrush start current is very low. 4) the pump is variable speed, so it will run only as fast as needed to produce the pressure required 5) the pressure was easily adjustable 6) a regulator system to protect the Merlins was not needed, simplifying the plumbing 7) because a regulator was not needed, the sap would not be thrashed through a regulator and causing foaming. 8) it does all of this on 110 V. Many sugar shacks do not have 220 V. ( 220 V models are availble. ) These pumps are available through Walrus USA in Texas. I have had a number of people contact me about the pumps and I think we will be able get some and ship into the NE states for $ 1200. US. Shipping and US customs and duty prepaid by us and included. Costs:
Life of the membranes is still a question but mine were still producing as well at the end as the beginning. They cost about $90. US to replace. You may find a less expensive pump and if you have a small number of taps, you might be happy with only one Merlin. We had 150 taps on vacuum and 325 on bags and buckets with a total haul for the year of about 4750 US gallons of sap. On the best days we could not really keep up with it, which is why we're planning on adding 1 or 2 more Merlins next year. if the pump output will drive them. We never detected any sugar in the permeate using a Misco digital refractometer. Every reading was 0.0 PS: If we had not had this RO system we would have run out of wood for the evaporator, and that would been a scramble to find wood at this end of the heating season. All in this thing saved us about 40 hours of boiling time. Something to think about: If you download the technical info on the Merlin, http://www.gewater.com/residential/home/merlin.jsp You can see that the amout of permeate ( clean water ) that gets dumped, you can see that it goes up dramatically with temperatures. The chart on page 12 shows 0.63 gallons per minute at 50 degrees and 1.03 at 80 degrees. Our sap goes in at closer to 40 degrees so it is even worse. If we found a way to pump the raw sap through a preheater in the hood of the evaporator, we could dramatically improve the performance. The trick is how to get the temperature to and control it at say 90 degrees without exceeding the 100 deg max limit. GE has just resonded to my request about how to store the Merlins in the off season with the comments that they are pickled in "Sodium Metabisulfite when shipped out of GE, for inhibiting the growth of organisms, which is going to be your main problem" I have asked what the concentration should be. I think I will try to preserve the membranes according to the instructions of the folks that make the Airablo units. You can see these at http://www.equipementslapierre.com/ 2010 Season: - add one or 2 more Merlins - add a UV sterilizer so the sap produces lighter syrup and the 1 micron filters should last longer. Update May 1 / 09 |
|||||||||||||||||||||||||||||||||||||
 |
Raw sap comes in through a 1 inch hose and goes directly into the pump. The pump output has a short 1/2" hose to a T where the flow is split to each of the RO's. Each RO has 2 lines coming out. All normally go outside. Two go back to the storage tank where the sap continuously gets more concentrated and two put the permeate (pure water) into 5 gallon water jugs. That water can be used to flush the membranes. |
||||||||||||||||||||||||||||||||||||