Filters: A Final Resolution To A Saline Solution
Initially the saline drip had no filter at all as there was insufficient time to assemble one, but come the 24th of May three rough hastily built prototypes had finally been disposed of and replaced with a more secure type which has the advantage of ease of access to replace the filter medium, obviating those leaks which gave me in particular, cause for concern.
A battery cell tester (I bought from a garage sale for the magnanimous price of $1) had both rubber ends removed and replaced with the appropriate size rubber stoppers with holes drilled to take the plastic hoses. This is a very useful piece of equipment to use for constructing a filter as it is simply an open ended glass tube.
The trick, (compliments of Para Rubber Company) to forming a hole in flexible rubber, is to leave it in the freezer for a few days prior to drilling it though the difference is negligible and the best place to acquire the perfect rubber stoppers complete with holes is your local home brewing shop.
The securing bracket is simple to make out of a thin gauge metal of any sort, using pliers and tin snips, (or perhaps even a piece of thin plastic cut from an ice-cream container using scissors) and may be shaped by bending it over a metal bolt or wooden dowel of similar diameter as the glass tube. Slotted holes for the screws make removal easy. Don’t screw it up too tight though!
Assembled to the wall (or whatever) as seen in the picture, the bracket may be slid off the fixing screws and the filter then have the bottom stopper removed for the filter water and filtering medium to be replaced, though you wont be doing that too often if there’s no sand and foreign matter in the salt water in the first place.
The medium I used is a small rolled up piece of material used in speakers to baffle sound. (I don’t recommend cotton wool.)
The gravity driven salt water enters at the bottom of the filter and exits through the top.
Of course an in-line tap is necessary somewhere between the top reservoir and the filter.