Abstract: A grout-gripping anchor for an underdrain block to be grouted to a filter floor is disclosed. Underdrain blocks have ribs extending outwardly from the exterior walls. The anchor is formed at the distant end of ribs positioned on the bottom exterior wall. The end of the rib widens to form one or more flanges or ledges so that grout covers the ledge when the underdrain block is grouted onto the filter floor. The anchor can be comprised of various shapes, including wedge-shape, rectangular shape or donut shaped.

Abstract: The invention relates to high-speed yarn traverse winding apparatus, method and product.Circling thrust members are provided to intercept a yarn being reciprocably traversed and forwarded to a bobbin in a winding zone to acceleratively control the reversal displacement of the yarn on the bobbin. A yarn package having a high resolution of symmetry is produced, the package being characterized in that the majority of the reversal curves of the helical windings are comprised essentially of camber curves generated substantially to a point of projected intersection of the diagonal linear extensions of the helical windings.