Criteria-based partitioning of large ontologies

A manufacturing method of the valve disk of spring loaded safety valves comprising, making its bottom portion as the pressure receiving surface, a cup-shaped center portion having an annular protrusion slightly inwardly from the peripheral edge of its bottom and a cylinder provided with an inwardly extending annular flange (valve lip) formed through bending its lower end, which is formed by continuous metal fibers, and contacting those two parts. More particularly, securing tight contact between the stage portions provided at least with one step beforehand around the outer periphery of said center portion and the inner periphery of said cylinder respectively when both are set in and, at the same time, maintaining an extremely narrow and uniform space between said annular protrusion and annular flange. Welding the contacting surfaces of said center portion and cylinder at a stretch by electronic beam.