| 摘要 |
A tube is made for installation in a system wherein the tube is to confine a fluid and to protect it from pollution. Promptly upon the making of the tube, both of its end portions are sealed by swaging them closed. Thereafter, the tube has two circumferential grooves formed on its outer surface, each inwardly adjacent one of the sealed end portions. Promptly before the installation of the tube in a system wherein it is to confine and protect a fluid, the sealed end portions are broken off at said grooves by twisting these portions with reference to the remainder of the tube.
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