Patent ID: 8720735

Claim:
A pressure vessel comprising: a vessel body having an inner surface; and an inclined nozzle projecting from a portion of said vessel body and extending from said vessel body along an axis inclined relative to a line orthogonal to the inner surface of said vessel body at said portion of said vessel body, wherein: a through hole of a circular section is formed through both said vessel body and said inclined nozzle and is centered on said inclined axis; an intersection of said inner surface of said vessel body and a surrounding surface of said through hole comprises a rounded portion throughout the whole circumference of the through hole; an inner opening of said through hole appears as a generally elliptic shape when said inner surface of said vessel body is seen in a direction orthogonal to said inner surface at said portion of said vessel body, the radius of the rounded portion at each of two positions corresponding to the major axes of said generally elliptic shape is smaller than the radius of the rounded portion at each of two positions corresponding to the minor axes of said generally elliptic shape, and the radius of the rounded portion continuously increases from each of two positions corresponding to the major axes of said generally elliptic shape to the two positions corresponding to the minor axes of said generally elliptic shape.