Pump Sizing for Single Post 4x40 build

[BSHC]

I am in the process of building a single post 4x40 RO. Trying to keep it simple and use a self priming Procon, not planning a recirculation line at this point. I am hoping to size the pump appropriately that I could add a second membrane in the future just in case it is too slow. We plan to run 500 taps this year. I have been looking at the Procon 330 and a 3/4Hp motor. Is this the best option or is it too much flow for this set up.
thank you.
Could not even think about this project without the help of Mapletrader .

[carls47807]

A 330 gph is probably too much flow for a single post unless you have a recirculation line. The membrane is only going to pull 50 gallons of water per hour, so you would need around 280gph of concentrate flow to keep from hitting the pressure regulator bypass.

You would want at least a 1hp motor for the 330gph (probably more like a 1.25 or 1.5hp). Using a 3/4 hp will only get you around 150psi (and probably still not a full duty cycle).

[BSHC]

that's kind of what I was thinking. I wondered if i should go with a 240 in order to be able to hit over 200 PSI with 3/4 HP at 100% duty cycle? Or do I even need a pump that big?

[carls47807]

It really depend on how you plan to run the system. The more flow across the membrane, the better. However, you still want to get a decent concentration in a single pass. If you recirculate the concentrate into the same feed tank and draw off of it when you are done concentrating the batch, then any size pump, even a 330gph will be fine. You will be drawing 50 gallons of water off per hour regardless of what pump you go with, but the additional gph beyond that will have to come out of your concentrate side if you don't have a built in recirc loop. A 240gph with 3/4 hp could probably handle 200psi for full duty in cold weather, but it is still pushing it. If you want to run it for 6-8 hours continuously at 200 psi or above you need a 200gph pump or less.

Once you get over 3/4 hp you will need to use a 56 frame motor with a coupling (which is a pain), so if you go that route you might as well get the 330 with a 1.5hp. The 48 frame motor clamps right to the pump (and is also considerably lighter) but the major companies don't produce them over 3/4hp.

[Urban Sugarmaker]

I would stick with a 330 GPH Procon and I would highly recommend adding a recirculation loop. It's a marginal additional cost - a needle valve and some tees, and a hose. It will give you a lot more control over flow and pressure and it's a very simple upgrade.

With 500 taps, a 330 Procon and 1.5 HP motor will give you the capacity to add a membrane eventually (I think you will want that with 500 taps).

I would not recommend ever running a procon dry even if they say it is "self-priming". At least have your feed tank above the elevation of the pump and allow sap to flow into the pump before turning it on.

[BSHC]

thank you for the feedback. My current issue with the larger pump is lack of available amperage. I currently need to run of a 75 foot extension cord. Long term may have a better set up but not in the cards this year. That is also why I want to self prime. I was going to use head pressure for that to protect the pump.
I was planning to just recirculation back into the tank as Carls suggested and maybe try to get up to 8% at max but would be happy with 6%. I have been back and forth with myself about the recirculation loop. I should probably just put it in but its also pretty easy to add.
Curious what you think the minimum and maximum sizes of pump would be suitable for this? Again thinking to stay with 3/4Hp max purely for electricity concerns. Currently exploring the Fluid-O-Tech 196 and 230 GPH options.
thanks again.

[sweet spot maple addict]

This is how we are set up
A single 4x40 with a procon 330 and a 3/4 hp
Operation pressure is between 135 and 180 ( temperature and brix related)
Water removal is about 45 gallons an hour (permeate removal)
So at 15 % recovery total feed has to be around 300 gallons an hour to avoid fouling
i would not suggest you go below that , and i dont think a 330 is overkilled, specially if a second membrane is in sight
It is wired on 240 , so it might be easier on the motor

[BAP]

Using a 75ft extension cord maybe your biggest holdback. Unless it is a heavy gauge cord, the voltage drop could cause problems with the pump motor leading to burn up of it.

[BSHC]

Using a 75ft extension cord maybe your biggest holdback. Unless it is a heavy gauge cord, the voltage drop could cause problems with the pump motor leading to burn up of it.
i agree with you. I have a 12 gauge cord and I am plugging in right beside the main panel in our barn so I should get 115 volts minimum.

[BSHC]

taking into consideration advice given and taking a little time to reflect I am going to put in the recirculation. Thinking I can run parallel to my evaporator which averages around 25gph using the recirculation. I still struggle with the pump. Using the Procon spec sheet it looks like I will be pushing it to maintain 150PSI with a 330/-3/4 combo limited by the motor. A 240-3/4 combo should maintain 200PSI. Seems however it may lack the flow required to keep the membrane from fowling? Does anyone know what CDL or others use on a single post with 3/4?
If i could run .42GPM or 25GPH roughly at 6 percent using recirculation loop i would be very happy but i have no idea how to calculate that.
thanks for your help

[Urban Sugarmaker]

Is there heat where the power is? Is the RO somewhat portable? Why bother with an extension cord if you can run the unit where the power is and run a 75' line for the concentrate? You can keep the raw sap and permeate tanks near the RO and pipe the concentrate to your evaporator. The pump will move it fine. May be a good solution until next season when you have all summer to work it out.

[BSHC]

Is there heat where the power is? Is the RO somewhat portable? Why bother with an extension cord if you can run the unit where the power is and run a 75' line for the concentrate? You can keep the raw sap and permeate tanks near the RO and pipe the concentrate to your evaporator. The pump will move it fine. May be a good solution until next season when you have all summer to work it out.
No heat in the barn. Unit is being built on a cart with the plan to be 100% portable. It is viable option, I would like close to keep an eye on things and is why i was thinking extension cord to just outside the sugarhouse window.

[sweet spot maple addict]

Does your motor has the flexibility to be wired on 240 ?
It will draw about 5 amps and should not be a problem on 75 ft of 12 gauge

[Urban Sugarmaker]

No heat in the barn. Unit is being built on a cart with the plan to be 100% portable. It is viable option, I would like close to keep an eye on things and is why i was thinking extension cord to just outside the sugarhouse window.

You can't go wrong keeping an eye on it. Again, running it dry will shorten its life rapidly. Mine has a low pressure shutoff. I think you could add that using a shallow well low pressure switch but I'm not sure how those work. Mine is a pressure switch connected to a microcomputer so it works a bit differently than a traditional relay. That said, a simple pressure switch setup is simple.

[BSHC]

Does your motor has the flexibility to be wired on 240 ?
It will draw about 5 amps and should not be a problem on 75 ft of 12 gauge
Good Point, I could do that if necessary. I feel like 10-11 amps on a 12 gauge cable should be ok.
Really trying to figure out right now what i need more, pressure or volume?

[sweet spot maple addict]

I would say you need both
Reverse osmosis is all about pressure over the osmotic pressure !
More pressure gives you the flexibility to handle colder sap, and still be efficient as the brix of
the incoming feed is increasing.
The higher volume, will contribute to an efficient sanitation and
will permit the addition of a second membrane
You cant go wrong with a 330 and a 1 1/4 or 1 1/2 motor
Its kind of : doing it right the first time !!!

Merry Christmas
sugaring in 2 months !!!

[BSHC]

I ended up going with a 200 GPH fluid-o-tech pump and a 3/4HP Marathon motor. Just need to get the motor wired up and plumbed.

[sweet spot maple addict]

200 GPH at 15 % recovery gives you 30 gallons an hour of permeate and 170 GPH on the concentrate side.
170 GPH or 2.8 GPM on the concentrate side is not much , a 4X 40 usually requires 4GPM .
Make sure you dont process over 15 % recovery for too long , and ajust the permeate/rincing interval consequently.

[maple marc]

Pierre, thanks for your posts. I got my Deer Run single post 4X40 RO unit last year. Worked well with my 250-350 gallon sap runs, probably not getting quite 4gpm concentrate out. Getting ready for this season and trying to understand optimal RO operation. Please give more info on "4x40 usually requires 4gpm; make sure you don't process over 15% recovery for too long," and rinse interval. I'm an RO rookie. Thanks.
Marc

[sweet spot maple addict]

For a 4x40 membrane the specs will usually specify a max feed flow rate of about 16gpm or 960gph which is related to the possible "mechanical/integrity" damage to the membrane structure if feed over that.
What they often dont specify is a minimum feed flow rate to avoid or delay the onset of fouling , which is about 4 gpm or 240 gph.
At 240 gph total feed rate if you apply pressure to get 40 gph permeate ( 40 / 240 ...16% ) it leaves 200 gph as concentrate flow rate out to act as a laminar flow across the membrane to "sweep" the surface and delay fouling. Operating below that minimum feed flow or above that pressure ( 15% recovery ) is possible , but the rincing procedure should be consequent.
Some operates at higher pressure , and higher recovery rates and it works. But it may not last as long !

[BSHC]

I am hopeful this will be adequate based on a couple things
1) based on advise from Carl @RO Bucket, this is basically the same as his set up in pump motor sizing. I am making an assumption that his works ok.
2) My average evaporation rate is about 25-26 GPH so that is all I really require for parallel operation.
3) The information I was provided from CDL was on there base unit the pump is3/4HP- 2GPM.

[BSHC]

another question. I see a lot of these using a 1/2 HP water pump prior to the high pressure pump. I was planning to just gravity feed but is there any reason a 1/4HP submersible pump would not perform the same task? Just curious.

[BSHC]

finally got to try the RO yesterday. Works better than I hoped. Used a small submersible for a feed pump instead of gravity. I was able to take 3% to 7% in a single pass using the recirculation line. Running right at 200 PSI I ran about 30GPH of Concentrate and 42 GPH of permeate.

[bmbmkr]

A 330 gph is probably too much flow for a single post unless you have a recirculation line. The membrane is only going to pull 50 gallons of water per hour, so you would need around 280gph of concentrate flow to keep from hitting the pressure regulator bypass.

You would want at least a 1hp motor for the 330gph (probably more like a 1.25 or 1.5hp). Using a 3/4 hp will only get you around 150psi (and probably still not a full duty cycle).



330/60 = 5.5 gpm.

Most 4x40" membranes will handle 14-16 gpm depending on the manufacturer & model. A lot of people run Procon 330's on 3/4HP. Might not hit the optimal pump curve, but it works.

Passive recirculation increases flow across the membranes which keeps them cleaner longer. Passive meaning teeing off some of the concentrate after it comes through the membrane, then feeding it back into the output of the pressure pump before the membrane. Use another needle valve to lower the pressure of the recirculation line.

I ran my 330 on a 1 1/2 HP but used 2 posts in series. Still 5.5gpm, actually a little more with a LP feed pump.