The present invention relates to a water aerating device or diffuser having a plate-like, rigid, round support plate that in the operating position is disposed essentially horizontally and that has at least one opening, the water aerator also having an elastic plate of rubber or other elastomeric material that rests on the support plate and is provided with a plurality of fine slits, whereby air can be introduced via the opening or openings between the support plate and the elastic plate and expands the slits. Also provided is a fastening ring that surrounds the support plate and is axially displaceable relative thereto, with the fastening ring acting upon the rim of the elastic plate that is disposed at the outer periphery thereof.
With the heretoforeknown water aerators of this type, the fastening ring presses the outer rim of the elastic plate against the upper surface of the rim of the support plate and thereby effects a pressure deformation of the rim of the elastic plate in order in this manner to establish a water and air tight connection. Although in this manner an airtight connection is achieved, it is however not practically possible to achieve a radial deformation or stretching of the elastic plate. In addition, a so-called retightening is essentially not possible in the sealing region because the thickness of the elastic plate is relatively small.
It is an object of the present invention to eliminate the aforementioned drawbacks of water aerators of the aforementioned general type, and in so doing to achieve a retightening of the sealing region and radial stretching of the elastic plate.