Water basin aeration pipe has perforated outer sheath with spiral ridge containing internal longitudinal groove

摘要

A water basin is aerated from the bottom up by a pipe (2) which is open to the air supply, but closed at the other end. The gas pipe has an aperture to a surrounding sheath (5) the inner face of which is separated from the pipe outer mantle by a perforated roof-shaped ridge, the interior line of which has a groove (51) running the length of the sheath. Preferred Features: The sheath ridge is preferably spiral shape around the length of the pipe (2). The sheath is preferably fitted in a series of separated helical sections. The depth of the groove (51) and the height of the ridge (53) are approximately equal, both being approximately one tenth the thickness of the sheath wall. The sheath is made of an elastic material preferably silicon rubber. The sheath perforations are made away from the immediate vicinity of the groove and ridge. The inner diameter of the sheath is larger than that of the pipe (2) outer diameter by at least the depth of the groove.