Watermaker is working...
January 19, 2009 - Day: 4 (1.2269S, 146.9071E) -1.2269S,213.0929W
As soon as I got some sun on the first day, I tested my electric desalinator. This watermaker is a great convenience when it works, otherwise I have to use a handpump to produce fresh water from the surrounding sea water. Trust me, I would rather row, even with an aching sciatica!
The watermaker relies on vacuum to draw water up from the sea then through the prefilter. Then a piston in the unit pressurizes the incoming salt water up to 800 psi, forcing it against a membrane. The pores on this membrane are small enough that the salt molecules do not pass, but smaller water molecules do. This filtration also eliminates the viruses and bacteria in the fresh water produced. The dribbling fresh water is collected for my use and brine is ejected with each stroke of the piston.
Back in General Santos City, I redid the intake hose for this unit. In my two previous rows, I had a lot of trouble with air leaking into the system which would stall the fresh water production. There were too many hose couplings which were potential vacuum leaks.
A thruhull fitting at the base of my footwell was the source of sea water from under my boat. I had added a course filter near the thruhull in 2007 before my Pacific launch. Another fitting went through the watermaker cabinet wall. I had also placed a booster pump inside the cabinet to feed the sea water into the prefilter, thinking that added pressure head may reduce the system's dependence on a strong vacuum.
I now had to simplify the hose layout.
In GenSan, I ran a new hose intact without any cuts from the thruhull all the way to the prefilter, eliminating a total of six hose couplings. For example, the course filter had two barbs, one for intake another for discharge. At each coupling, the hose would be attached to a barb, then clamped. To route the hose through the cabinet wall without cutting it, I used a fitting which is normally used to seal cables going through bulkheads.
I have used the watermaker every day by now, and so far not a bubble of air has appeared in the prefilter. I had spent so much effort babysitting that unit on my previous 312 days. I suspect the original culprit was the fitting through the cabinet wall, but that's water under the bridge. Now it is almost as easy as: I turn on the switch, and I get fresh water!
Yesterday for example, I made 2 gallons of fresh water which was enough to replenish my drinking supplies and to rinse my laundry and my body after washing with salt water. I have special soap for salt water -- regular soap will not lather with salt water. And salt unrinsed is itchy when worn against the skin; it creates tiny blisters on the skin surface which are even worse when scratched. My long sleeve shirt which I have to wear for sun protection, gets enough salt from my own perspiration that it has to be rinsed every day or two.
As long as I have sun to recharge my batteries, I will have easy access to water. When it is up, the sun is scorching hot where I am this time of the year... For now my major complaint will be the heat.
Erden.
|