Tuesday, January 10, 2012

Refinements to the Water Maker

As mentioned in the prior posts, we have had issues with the Heat Exchanger.  Not in its operation, but in its construction of the mounting flange.  It is rather soft material, and very thin; causing distortion and making it difficult to keep it sealed correctly.  In this closeup photo of the flange  you can see what I am talking about..

Addressing this,I soldered on some brass stiffening trips as you can see here.  I used 1" x 3/32" stock, purchased from a local hardware store.  If you can find thicker (ala 1/8") it would work fine, but need to have it 1" wide.

Yesterday I bolted it back on, and it seems to be working well - at least the flanges no longer distort!

While I was at it, I also took the opportunity to re-route some of the plumbing as shown in this update diagram.  The difference is we now run the sea water through the heat exchanger before sending it to the RO membranes.  The reason for this is Revise Osmosis membranes are temperature sensitive.  When they say 40GPH, it is when using a water temp of 77oF.  Up here we see water in the 40's to the low 50's.  It might get up to the mid 50's during the summer,but never to the 70-80o range.  By pre-heating the water I am expecting to get more produced out of the membranes while still keeping them within their design specification.  Once we get underway next month and start using the Water Maker again I will report on its performance.

Click to make larger

Update:  See some more thoughts on this pre-heating idea here:

And one last point:  Those motor mounts I used, the ones I just plucked from someone else's design that I thought were a bit on the small side.  Well, yup.  While inspecting things I noted one has collapsed.  Does not impact anything other then a bit more noise put into the hull.  But those are obviously one part that is not right.

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