Relining process for interior surface of a hollow article

Abstract

Cryogenic process and apparatus for removing adherent coatings or linings from metallic substrates, especially the interiors of metal vessels or pipes. In one embodiment, a metal vessel having a polymeric interior lining is pressurized to about 900 psi, and the lining is contacted with a cryogenic liquid, preferably carbon dioxide, while this pressure is maintainted. The pressure is high enough so that the cryogenic liquid does not boil. The lining is then subjected to shock by ultrasound, for example. This causes the lining to break up into small particles and fall off the metal substrate. These particles, suspended in the cryogenic liquid, are removed from the pressure vessel and separated from the cryogenic liquid, which can be reused. In another embodiment, the cryogenic liquid is injected into a pipe having an adherent mineral deposit while maintaining a pressure of about 700 psi. A stream of cryogenic liquid containing suspended mineral particles is removed from the pipe.

Dependencies are inferred from the claim text.