Abstract: A filter ring is described for insertion in ring-shaped apertures or openings of the wall of hollow bodies containing or through which gases or liquids flow. In its wall surrounding a hollow space, the ring has a longitudinal slit extending parallel to the axis of the ring along the entire axial length of the ring, the wall portions of the ring located to both sides of the slit being joined with one another by a snap lock. In accordance with the invention, this snap lock has at least two projections which are arranged in the one wall portion of the ring in an axial direction and which are snappable into grooves arranged equally adjacent to one anotehr on the other wall portion. The projections and grooves extend over the entire thickness of the ring wall and have side surfaces undercut in the joint direction and engage one another from behind.

Abstract: The invention relates to a hollow body, in particular a pipe segment or a cylindrical body which contains gases or fluids or through which these can flow and comprises at least one opening in its wall surrounding the hollow space of the hollow body, the opening entering into a ring groove in the hollow body wall which extends around the entire outer periphery of the hollow body and over which opening a filter mesh strip located in this ring groove is spanned. In both side wall of this ring groove there are provided essentially opposing slot-shaped recesses extending annularly with the groove. The filter mesh strip is inserted into these recesses and held there by both its side edges.