US 4,364,161 AGranted

Method of fabricating a high pressure tank

AssigneeThe Marison Company

InventorRussell C. Stading

Life of this patent

Estimating the term…

Loading patent…

Abstract

A tank and method for fabricating the tank are disclosed wherein a longitudinally seam welded segment of a generally cylindrical steel tube is formed by hot spinning into a cylinder. The cylinder is heat treated, shot blasted, and non-destructively tested to verify that the heat treatment is uniform and proper, that the wall thickness is as desired, and that the weld region is acceptable with no critical defects created as a result of the hot spinning and heat treating. The cylinder is pressurized with air to a predetermined pressure to verify that there is no leakage from the spun closed end of the tank. Finally, the cylinder is hydrostatically tested to a predetermined pressure level with water and the cylinder weld is simultaneously examined by means of acoustic emission with the cylinder stressed in response to the internally applied hydrostatic test pressure to determine if a paste weld condition exists.

A method of fabricating and testing a tank for storing and transporting high pressure gases comprising the following steps:

(a) providing a steel strip formed into a substantially closed curve configuration with the longitudinal margins thereof in an aligned and adjacent relationship and effecting an electrical resistance seam weld along said adjacent margins to form a length of seam welded tubing;
(b) ultrasonically examining the weld region of the tubing for voids and lack of fusion to 5 percent of the tubing thickness;
(c) effecting a final forming of the tubing to a desired diameter and then subjecting the circumference of the finally formed tubing to a flux leakage test for flaws and critical defects;
(d) hydrostatically testing said tubing for paste-welding;
(e) hot spinning the finally formed tubing to form a tank with a cylindrical sidewall, a bottom, and a neck;
(f) heat treating said tank;
(g) shot blasting said tank;
(h) non-destructively testing said tank with ultrasonic and eddy current techniques to verify that the heat treatment is uniform and proper, that the wall thickness is as desired, and that the weld region continues to be acceptable with no critical defects created as a result of said hot spinning and said heat treating;
(i) spot facing the neck end of the tank, facing the neck to the desired length, turning the diameter for the neck ring when required, predrilling a hole through the neck, core drilling a bore in the neck for subsequent tapping, and tapping the formed bore;
(j) discharging steam into the tank with the tank in inverted position until the inside of the tank is clean and hot;
(k) vacuuming the inside of the tank until it is clean and dry;
(l) pressurizing the tank with air to a predetermined pressure to verify that there is no leakage from the spun closed end of the tank;
and
(m) hydrostatically testing the tank to a predetermined pressure level with water and simultaneously examining the tank weld by means of acoustic emission with the tank stressed in response to the internally applied hydrostatic test pressure to determine if a paste weld condition exists.

11 more elements

Abstract

Claims2