Watermaker - Cat pump output

[svrevelations]

I'm looking at building a new water maker and I am looking at the Cat 3CP1221 high pressure pump. The water maker will be be direct connected to a 2.9 HP single phase 220 volt 50/60hz electrical motor.

This pump is rated at 4.2 gallons per minute - but that will surely not be the output of fresh desalinated water. I know that the production of fresh water is also influenced by the intake water temperature. The electrical motor will also run about 20% faster on 60hz than on 50hz - thus producing more freshwater.

I have some questions;

1. To reduce a large number of membranes, I am keen on 8" x 40" membranes. But how many of these would I need?

2. Operating at 50 hz and 80 bar, can anybody give me a clue (more or less) how much fresh water we can expect this pump to produce?

[Abgreenbank]

Your pump is too small for 8 inch units and just adequate for a 4 inch membraine, you should get over 200 l/hour at 800psi, a 4 inch membraine can produce around 300l/ hour but don't think your pump output is enough for that.
4 inch membraines have a max of 69 bar but 60 ish bar is adequate. Your pump hp looks ok for the stated output.
You will need lots of generator to start a 2.9 hp single phase motor.
8 inch units can produce around 1200l/hour which is similar to your pump output so that isn't happening!

Regards ab




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[svrevelations]

Originally Posted by Abgreenbank

Your pump is too small for 8 inch units and just adequate for a .......................... that isn't happening! Regards ab

Thank you for your response - much appreciated!
It will probably be easier to buy a ready made unit, but it is far more satisfying to build our own unit.

We have a 13 KVA 220 volt 50hz single phase generator on board.
I'm looking to maximize our fresh water making capacity - but do not have all the answers.

[Abgreenbank]

its not difficult to make your own but look at:

Cruise RO Water & Power: Watermakers for Boats & Yachts

its difficult to make your own cheaper and Rich has ironed out most of the problems

regards

Ab

[Oceanride007]

If you intend running a 50Hz motor at 60Hz, yes you will pump more. But unless the name plate says you can (not likely), I'd expect it too start smoking sooner or later. Apoligies if I have mistaken your intent.