Methods of forming bodies of expandable foaming material

Abstract

In order to decrease the height of a solid foam body produced from a pool of foaming liquid as the foaming liquid solidifies into the solid body, the height of a bottom mold face is decreased by sloping the mold face so that there is less liquid at higher locations of the mold face than at lower locations. This technique is especially useful in making seals for filter elements, wherein the filter elements are annular in horizontal cross-section so that less sealing material occurs adjacent the downstream clean side of the filter media comprising the filter element than adjacent the upstream dirty side of the filter media. In a particular application, a filter element with a frustoconical filter media has one end sealed by a rising volume of solidifying urethane foam so that more foam is adjacent the outside surface of the filter media than the inside surface, and so that the foam also forms a peripheral gasket adjacent the outside surface. In this way, a filter element is provided which has more uniform air flow when used as an air filter with an internal combustion engine. This improves the mass transfer function of the filter and thus engine performance and exhaust emissions.

Dependencies are inferred from the claim text.