 Check out the bookstore at IRBS.com |
|
|
|
|||||
|
||||||
From: Norm of Bandersnatch (no email)
Date: Fri Aug 18 2006 - 09:14:28 EDT
my machine is rated at 25 gph of product and there is a red line at 2 gpm
of seawater flow. the shop you buy your machinery from will be able to
determine this too. they will provide advice as well as the equipment.
using the pressure in the seawater discharge is the principle of the
Spectra 'pressure increaser' pump. it uses two opposing pistons, one on
each end of a rod, each operating in it's own cylinder with a valve
switched by a detent on the rod as the pistons move back and forth. the
ideas is that the discharge pressure and the inlet pressure almost balance
each other so that you only have to add the energy that the product leaving
through the membrane represents.
This is the main reason the Spectra is more efficient than 'normal' RO
units.
I don't know the details of RO units on big ships.
As product is subtracted from the seawater the seawater gets saltier.
Saltier water produces less product, so a second pass of the same seawater
would produce less water and be counterproductive.
the 800 psi is not a problem with the proper pump. the pump on my machine
is capable of much higher pressures. the relief valve controls the
operating pressure. higher pressures produce more product, but the
resulting saltier water is not good for the membranes i have been told.
Norm
S/V Bandersnatch
Lying 30 07.7N 081 39.6W
Julington Creek Estuary FL
> [Original Message]
> From: ahmet erkan <>
> To: <>
> Date: 8/18/2006 8:31:41 AM
> Subject: Re: lv-ab: Bandersnatch's Watermaker
>
> >it is a good thing to
> >include only enough of the original message to remind folks of what the
> >thread is about. as the great proffesor strunk once said,...............
>
> Kudos to the great prof.
>
> Back to subject of Watermakers :
>
> >filtered water is fed to the input of
> >the high pressure pump which is the same sort of three cylinder pump used
> >in pressure washers, then to the membrane housings which may be several
in
> >series, then to a pressure relief valve you set to 800 or so psi
depending
> >on conditions, then overboard.
>
> The process makes sense except I can't figure out how to determine the
> optimum ratio of discharge overboard per unit of product generation to
> regulate the salinity on the high side of the membrane? 1 : 1 ? Also,
would
> the efficiency be better if the 800psi discharge was to go into a water
> driven engine and helped the main HP pump? Do they already have such
systems
> on big ships? How much of an impact on efficiency ? How about no
discharge
> overboard but periodic back flush cycles ?
> If we are going to integrate our own watermakers, we might as well learn
all
> the details. It don't sound too easy with 800psi etc but not rocket
science
> either.
> Maybe Norm or the person with the home RO systems experience can comment?
>
> Thanks in advance,
>
> Ahmet
> SV8827
>
>
>
___________________________________________________________________________
> || The Live-Aboard List : send a "subscribe" or "unsubscribe" request
||
> || in body of message to:
||
___________________________________________________________________________
|| The Live-Aboard List : send a "subscribe" or "unsubscribe" request ||
|| in body of message to: ||
|