Watermaker Membrane - Change to Larger = Increased Output?

[Cheechako]

More membranes need more volume not more pressure...right?

[Lancerbye]

I guess this is called thread recycling. I agree with Cheechako to a point. I have a Village Marine Modular A/C unit with two 2.5 x 21 in membranes producing 16 Gal/hr. I can increase the output by adding more membranes or bigger membranes to a limit. The limit is determined by the output of the CAT high pressure pump. Pump capacity will be the final limiting factor. The unit I have will allow to be increased from a 400GPD to 800GPD without having to increase the size of the pump.

[Tellie]

Pressures have to remain in the same range. Adding membranes will require more flow/volume under the same pressures. Some watermakers with larger Cat type plunger pumps are capable of creating more flow and maitaining pressure if an additional membrane is added. Many smaller watermakers who are designed for energy efficency have plunger type pumps that are rated just enough to handle the membrane size it is designed for and no more.

[siroismi]

Hi all

I have a VMTec Modular MPW-600 A/C unit with 3 X 20"X2.5" membranes and a Titan series 2.3 GPM pump.

Anybody knows if I could get production up to say 33 GPH instead of the actual 25 GPH with a change of membranes?? I just don't know if that pump gives out enough volume.

I was thinking of replacing thoses proprietary VM membranes that cost twice more than equivalent Dow Filmtech for say two 2.5 X 40". Even with the cost of new vessel it would pay itself eventually.

Any recommendations?

Thanks
Michel

[Lancerbye]

I suspect your pump might be a bit too small. The one I am using is 3.5GPM and if I expanded my 16 gph to 32 gph I would be at the max capable for this pump, according to the info I have from VM.

[SvLetitgo]

One of the way to find out is to use Rosa see post below

Buying vs building your own water maker (Part 3) · SV Letitgo

All pump can do 800PSI if not they couldn't make fresh water from salt water. In today technology available to us.

The flow rate of the pump is what drive the output been that it's a % of it.
Also to be taken in consideration is the inability to "auto clean" itself of the membrane if it doesn't get enough flow.

[siroismi]

Thanks for replies.

After digging for info on the net it seams that by going with membranes 2.5 X 40 my production would go from 600 to 800 gpd (or 33 gph) and that pumps would be sufficient as for the flow.

Hopefully the experts on this subject that we hear from on this board can confirm...

Michel

[SvLetitgo]

What pump do you have model number, and how many membrane are you looking for

Please

[Cheechako]

I had a 3 membrane unit , 20" I think. The end fitting s went bad etc and the membranes were old so I opted to just put one long membrane in instead of the 3. I didnt really check output before or after, but I seemed to get as much water made and the whole system was a lot simpler plumbing.

[siroismi]

I have for pump the AquaPro Titan Series #708-3(23). It is a 2.3 gpm flow rated.
For membranes I have 3 X 19x2.5" and am considering 2 X 40x2.5" or maybe a single 4" one.

I still don't know what's the maximum membrane I can use and max production I can get with this pump.

Thanks again for your input guys.

Michel

[SvLetitgo]

Let's try a few calculation

2.3GPM is about 138 GPH with one 25w40 producing around 13% (conservative and depend on lots of factor) that 18 GPH of fresh water.

If you add one more of the same you get 50% more that 27GPH.

When I run the number in Rosa no alert come of it, so it seem that you are in good shape.

[siroismi]

Originally Posted by SvLetitgo

Let's try a few calculation

2.3GPM is about 138 GPH with one 25w40 producing around 13% (conservative and depend on lots of factor) that 18 GPH of fresh water.

If you add one more of the same you get 50% more that 27GPH.

When I run the number in Rosa no alert come of it, so it seem that you are in good shape.

If I add a second membrane 25w40, I tought it would double the production?

Thanks for info
Michel