Filament wound spherical pressure vessel

Claim 1

A substantially spherical filament reinforced plastic pressure vessel wherein said vessel is to withstand a preselected meridianal force of N pounds per inch and a preselected hoop force of N pounds per inch, said vessel including means for permitting deformation of said vessel upon pressurization thereof to exhibit throughout the entire vessel an ability at all planes perpendicular to the polar axis to withstand a substantially constant meridianal force of N and at all planes parallel to said polar axis to withstand a substantiallY constant hoop force of N , said last mentioned means comprising a plurality (m) of helically wound layers of filament, the convolutions of which follow substantially great circle paths, each winding layer being composed of windings disposed in planes which intersect the centEr of the polar axis of said sphere at an angle of inclination ( Alpha ) that is different from said angle of inclination of the windings of the other of said layers, said winding layers being designated progressively from 1 to m in accordance with their respective angles of inclination, said winding layer 1 satisfying the equation wherein: T maximum tensile stress of the filament Eta the angle defined by the intersection of a line running from the circle of intersection of an arbitrary selected analytical plane perpendicular to the polar axis and the surface of sphere to the center of the sphere with the polar axis a radius of sphere i the number of the layer Ni number of turns in the winding layer at Eta Alpha 2; said winding layer (m) satisfying the equation at Eta 90*; and windings (2) through (m- 1) satisfying together with the windings of more acute angles of inclination, one of said two equations at analytical planes intersecting the surface of said sphere at Eta Alpha i+1.