Abstract: The invention provides a heat-pipe for a rotational molding apparatus.

Abstract: A heat pipe, a rotation molding apparatus comprising a heat pipe, a rotational molding, and a method of molding comprising using a rotational molding apparatus, are provided.

Abstract: A grate cover in combination with a swimming pool being installed in a recess in the top of a sump. The grate is formed of an upper and a lower section. The upper section exhibits four squares or four triangles therein, The upper section has a dome-shaped configuration and has four square or triangular shapes therein, depending on the geometric division therein, each shape has openings therein. The lower section has four trapezoid shapes therein. Each of the shapes of the upper section, whether square or triangular, has a concave surface curvature therein at a transition between the upper and the lower section. Each of the trapezoids of the lower section has two concave surfaces- curvatures therein. One curvature extends in a first direction from the upper section toward an outside edge of grate cover. The other second concave curvature extends in a direction which is normal to the first direction.

Abstract: A grate cover in combination with a swimming pool being installed in a recess in the top of a sump. The grate is formed of an upper and a lower section. The upper section exhibits four squares or four triangles therein, The upper section has a dome-shaped configuration and has four square or triangular shapes therein, depending on the geometric division therein, each shape has openings therein. The lower section has four trapezoid shapes therein. Each of the shapes of the upper section, whether square or triangular, has a concave surface curvature therein at a transition between the upper and the lower section. Each of the trapezoids of the lower section has two concave surfaces- curvatures therein. One curvature extends in a first direction from the upper section toward an outside edge of grate cover. The other second concave curvature extends in a direction which is normal to the first direction.