4" x 40" RO Build

Over the past several years I have found that I needed to run two of the smaller systems to keep up with the amount of sap I was collecting each day.  At the end of last season I realized I had a faulty pump and also needed to replace all the membranes for both units.  I decided to build a larger unit and sell off the smaller ones.  A big thank you to  Plymouth Sugar Works for all the help and advice.  Please be aware that I will be testing this setup during the 2023 season and will update this page at the end with any recommended modifications.

My goal was to build a system that would allow me to process 1.5% sap to a 12% concentrate (recirculating) in few hours.  I usually collect between 150-200 gallons per day and I am hoping to process it all in about 7 hours.  At 12% concentrate I will be able to make a gallon of finished syrup per hour on my 24" x 36" divided flat pan evaporator (evaporation rate = 6gph)

I went with a 3/4 hp motor and 240 gph pump along with a 4" x 40" membrane.  It is wired for 240 volts and used PEX A tubing and push to fit Sharkbite fittings.  I will be updating with the final fittings and valves needed after I run the system for a while.

The operating and cleaning instructions are the same as listed on the previous page.  The only difference is I will be using a 10 gallon container instead of 5 due to the larger membranes and flow.

With similar systems costing over $2000 it was well worth the time and effort to build it myself.

February 8 - First test run - 105 gallons of 2% sap:  The system was able to process all the sap in 2 hours removing 90 gallons of water (85%) leaving 15 gallons of 13.8% concentrate. 

February 21 - system has been running great.  I have found that I am able to remove approximately 50 gallons of water per hour for any amount under 300 gallons.  I also have not exceeded 250psi.

March 10 - 2700 gallons of sap went through the RO (1.7% average sugar content),  330 gallons of concentrate (13% average concentrate).  The system averaged 50 gallons of water removal per hour recirculating.  I did have a few issues including cracking 2 end caps and a failed O ring.  I caused these issues by over tightening the fittings and using a thin silicone grease.  If anyone is going to build one order extra O rings, end caps and use a thick high quality silicone grease/lube (SuperLube works great).

Only change I would make to the design would be to plumb the membrane housing upside down - so the feed is on the bottom and the permeate and concentrate lines on the top.  I would install a threaded tee into the concentrate port and install the pressure gauge on one end and the tubing to the needle valve on the other.  This would eliminate a lot of the tubing and since it mounted on a  hand truck you can lay it down flat and drain the membrane housing out the top.  This would also reduce the number of fittings and tubing needed.  If you mount this way the total cost to build this unit with parts listed below, including fittings, would be around $1200.

DAYTON Carbonator Pump Motor: Cradle Base Mounting, 3/4 HP, 1,725 Nameplate RPM, 115/230V AC  $205

PROCON Rotary Vane Pump: 1/2 in Inlet/Outlet NPTF (In.), 260 gph Max. Flow (GPH), Brass, 240 gph GPH  $242

Max Water 4040 Commercial Reverse Osmosis 304 Stainless Steel Pressure Vessel 4"x40" Membrane Housing  $100

MES 4” MEMBRANE $230

Amwater NSF Stainless Steel Filter Housing for Filter Cartridge, Water Filter Housing for Whole House Water Purification of Stainless Steel 304 (10" A Housing-3/4NPT)  $100

IMXMI Water Filter, 1/2''Twist-On Pipe Strainer, Nylon PA66 cover, PC bowl, 304 Stainless Screen (1/2''40 Mesh Female water filter) $15

MEANLIN MEASURE 0~400Psi Stainless Steel 1/4" NPT 2.5" FACE DIAL Liquid Filled Pressure Gauge WOG Water Oil Gas Lower Mount  $15

FRANKLIN 800 lb. Capacity Hand Truck  $75

1/2 in. x 100 ft. Blue PEX-A Expansion Pipe in Solid  $40

1/2 Inch G Valves 304 Stainless Steel G Female Needle for Valve Flow Control Water Gas Oil,Ferrule Straight-Through Female Needle Valve,Control Needle Valve $25.59

Shark Bite Fittings: about $100- $200 total - sometimes they have bulk containers for each part that will cut down the cost.  You can also go with barb fittings and rings but the additional cost of the push to fit connectors will allow you to disconnect and clean much easier.  The number of each you will need depends on how you mount your membrane housing and if you are going to use SharkBite push to fit connections or regular PEX crimp fittings.

$13  Tee 

$10 Elbow  

$ 8 Threaded adapter  

$ 20 Ball valve 

Legines Brass Pipe Fitting Hex Bushing 3/4" NPT Male x 1/2" NPT Female Adapter 1200psi ( 2pcs ) $12 these are for the 10" water filter housing

iCrimp Push-to-Connect,Push-fit Disconnect Clamp Tool for Brass-Push Fittings Removing,Multi-size Combination 1/2",3/4",1"-CRQ02  $20

Bates- PVC Pipe Cutter, Cuts up to 1-1/4", Ratcheting PVC Pipe Cutter Tool, Pipe Cutters PVC, PVC Pipe Shears, PVC Cutter, Plastic Pipe Cutter, PEX Pipe Cutter, PVC Cutter Tool, PVC Ratchet Cutter  $10

Milrose 70885 Blue Monster 1/2 Inch x 1429 Inch Blue Teflon Tape (3 Pack) $15

Replacement Parts that are helpful to have on hand

Gazechimp RO Housing End Cap For 4" Membrane Pressure Vessel Filtration Parts $15 

Super Lube 92016 Silicone Grease with Syncolon (PTFE), Translucent White $37

417 O-Ring, Silicone, 70A Durometer, 3-1/2" ID, 4" OD, 1/4" Width, Red (Pack of 5) $18

210 Silicone O-Ring, 70A Durometer, Red, 3/4" ID, 1" OD, 1/8" Width (Pack of 100) $10