Most showerheads disperse water by forcing it thru a screen of small holes. That is fine unless your water is full of chunks of sediment which then blocks the holes.
The no screen showerhead sends water into a series of grooves which then spiral out along the inside of the conventionally trumpet shaped showerhead. Water emerging from the end of the showerhead continues along its prior trajectory. Chunks are borne along in the flow. One spreads the water available to optimally wet the shower-taker without any screens or holes in the way.-- bungston, Jan 23 2012 Super! easy to clean too!-- pocmloc, Jan 23 2012 Argh! Mineral sediment in my eye!-- Alterother, Jan 23 2012 There's a jet-engine fuel injector that works somewhat like the description. (There are also jet engines that centrifuge the chunks out of the air on the way in.) [+]-- baconbrain, Jan 23 2012 <contemplates image of [bungston] carrying out the first and only test of the new JT-8D based showerhead>
[+]-- 8th of 7, Jan 23 2012 random, halfbakery