METHOD OF MANUFACTURE OF ENCLOSURES OF REVOLUTION FOR PRESSURES AND TEMPERATURES DIFFERENT FROM AMBIENT PRESSURES AND TEMPERATURES

摘要

1455425 Making composite tubes; jointing FOUNDATION OF CANADA ENG CORP Ltd and BVS 15 Nov 1973 [20 Nov 1972] 53140/73 Headings B3A and B3V In a composite tube for withstanding high internal pressures at low temperatures in which an outer envelope is made of a material having a larger coefficient of expansion than that of the material of an inner tube, the fit of the envelope on the inner tube at ambient temperature is such that the desired hoop stress in the tube due to differential thermal contraction does not develop until the composite tube has reached the low operating temperature. The envelope may be in the form of a sleeve, spaced hoops or a wire, ribbon or cable. Formulae (8), (13) are included in the Specification for determining the initial difference in diameter between the outside of the inner tube and the inside of the envelope for a tube fixed at the ends and one additionally stressed axially, e.g. by the presence of a valve. If the initial difference does not permit a sliding fit, the tube may be made under-size and the composite expanded beyond the elastic limit of the tube in order to produce the desired initial fit, or the envelope may be shrink-fitted. Alternatively, the tube may be expanded and a helical bandage applied, or the bandage may be applied to a sleeve and the tube inserted in the sleeve which offers no resistance to contraction.