i have made two ring type sparge arms that gently let the water drop on top of the water on the grain bed ( i usualy leave 1/2 to 1" of water above the grain bed while sparging). Here is a pic of my copper arm. I also have made one using high temp hosing. The copper one was to0 rigid and got in the way when doughing in my grains.
I origianlly wanted a rotating arm, but i made this pretty cheap.