Patent ID: 8714400
Filing Date: 2014-05-06
Classification: F16J,F17C

Abstract:
1. A pressure vessel, having: a polygonal upper wall; a polygonal bottom wall provided on the lower side of said upper wall; a side wall provided between a peripheral edge of said upper wall and a peripheral edge of said bottom wall; an upper curved surface portion for connecting the peripheral edge of said upper wall and an upper end of said side wall by curved surfaces convexed outward; and a lower curved surface portion for connecting the peripheral edge of said bottom wall and a lower end of said side wall by curved surfaces convexed outward, wherein in order of decreasing thickness are an upper wall center portion in center of said upper wall, said upper curved surface portion, and an upper wall annular portion formed between said upper wall center portion and said upper curved surface portion, and in order of decreasing thickness are a bottom wall center portion in center of said bottom wall, said lower curved surface portion, and a bottom wall annular portion formed between said bottom wall center portion and said lower curved surface portion.