Method of detecting imperfections in a heat-insulating lining

• US 3,934,451 A
• Filed: 05/29/1973
• Issued: 01/27/1976
• Est. Priority Date: 06/02/1972
• Status: Expired due to Term

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Bristoll, Paul, Arink, Godefridus
• Primary Examiner(s): Goldstein, Herbert
• Application Number:
  US05/364,394
• Time in Patent Office: 973 Days
• Field of Search: 73/15 R, 73/15 FD, 73/15.4, 73/104, 220/9 LG
• US Class Current: 374/5
• CPC Class Codes: F17C 13/126 for large storage containers for liquefied gas for large containers in general B65D90/22
• CPC Class Codes: F17C 2203/03 Thermal insulations
• CPC Class Codes: F17C 2221/033 Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
• CPC Class Codes: F17C 2223/0161 cryogenic, e.g. LNG, GNL, PLNG
• CPC Class Codes: F17C 2260/04 Reducing risks and environmental impact
• CPC Class Codes: G01N 25/72 Investigating presence of flaws

Abstract

A method of detecting imperfections in a heat-insulating lining of foamed material of the wall of a space suitable for cryogenic uses by cooling the surfaces of the lining by scanning with a jet of cooled gas and observing the lining for imperfections in the cooled state.

Claims

1. A method of detecting imperfections in a heat-insulating lining of foamed material of a wall enclosing a space suitable for cryogenic uses, comprising locally cooling the surface of the lining by scanning with a jet of cooled gas and observing the lining for imperfections in the cooled state.

2. The method of claim 1 comprising utilizing vapors of liquid nitrogen for cooling.

3. The method of claim 1 including photographing the imperfections in the cooled state for marking purposes.

4. The method of claim 1 including marking the imperfection while it remains visible in the cooled state.

5. A method for detecting a crack or split in a foamed lining on the inner surface of a wall of a tank utilized for transporting a cold liquid comprising temporarily and locally cooling the surface of the foamed lining with a jet of cooled gas in order to cause the surface to contract and thereby render the crack or split visible without magnification and marking the crack or split while it remains visible.

6. A method for detecting a crack or split in a foamed plastic material in which the crack or split enlarges upon cooling of the material by subjecting the material to temporary and local cooling whereby the crack or split becomes visible as the plastic material shrinks and the crack or split widens, and marking the crack or split while the plastic is in the cooled state.