Supporting arrangements for porous diffusers

In a gas diffusing system of the type comprising an elongated gas supply pipe having a gas discharge opening in a side wall thereof, a porous diffuser of substantially disc shape, and a unitary supporting element engaging the periphery of said diffuser and located between said diffuser and the exterior of said gas supply pipe adjacent said gas discharge opening for supporting said diffuser on said pipe in outwardly spaced relation thereto, said supporting element cooperating with said diffuser and said pipe to define a substantially enclosed gas chamber exterior of said pipe adjacent said gas discharge opening, the improvement wherein the side walls of said pipe define a pair of spaced recesses each of which is positionally displaced from said gas discharge opening on opposite sides thereof respectively, said unitary supporting element including a pair of spaced, load-bearing limbs positioned to straddle said gas supply pipe and adapted to be resiliently flexed away from one another as said limbs are pushed onto said pipe on opposite sides of said gas discharge opening respectively, and a pair of projections on said limbs respectively extending toward one another and spaced from one another by a distance less than the length of the chord between said spaced recesses in said pipe whereby said projections snap into and interengage with said recesses respectively when the limbs of said supporting element are pushed onto said pipe thereby to positively locate said supporting element relative to said pipe.