Methods of testing thermal insulation and associated test apparatus
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsJames E. Fesmire, Stanislaw D. Augustynowicz
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Abstract
The system and method for testing thermal insulation uses a cryostatic insulation tester having a vacuum chamber and a cold mass including a test chamber and upper and lower guard chambers adjacent thereto. The thermal insulation is positioned within the vacuum chamber and adjacent the cold mass. Cryogenic liquid is supplied to the test chamber, upper guard and lower guard to create a first gas layer in an upper portion of the lower guard chamber and a second gas layer in an upper portion of the test chamber. Temperatures are sensed within the vacuum chamber to test the thermal insulation.
Claims13
A method for testing continuously rolled thermal insulation in a cryostatic insulation tester comprising a vacuum chamber and a cylindrically-shaped cold mass including a test chamber and upper and lower guard chambers adjacent thereto, the method comprising the steps of:
- surrounding the cylindrically-shaped cold mass with the continuously rolled thermal insulation;
- enclosing the thermal insulation and cold mass within the vacuum chamber;
- adjusting vacuum pressure inside the vacuum chamber to a desired vacuum level;
- supplying cryogenic liquid to the test chamber, upper guard and lower guard chambers to partially fill the test chamber, upper guard and lower guard chambers with liquid, creating a first gas layer in an upper portion of the lower guard chamber and a second gas layer in an upper portion of the test chamber;
- and
- sensing temperatures within the vacuum chamber to test the thermal insulation.
A method for testing thermal insulation positioned adjacent a cold mass assembly including a test chamber, an upper guard positioned adjacent one end of the test chamber and a lower guard positioned adjacent the opposite end of the test chamber comprising the following steps:
- positioning the thermal insulation and the cold mass assembly within a vacuum chamber;
- controlling the temperature adjacent the vacuum chamber
- supplying a sufficient quantity of cryogenic liquid to partially fill the test chamber and the upper and lower guards, creating a gap in the test chamber and a gap in at least the lower guard;
- continuing to partially replenish the test chamber and upper and lower guards with cryogenic liquid until the temperature of the insulation material and the vacuum levels reach stable equilibrium;
- stopping the flow of cryogenic liquid to the test chamber, creating a gas layer between the cryogenic liquid in the test chamber and the cryogenic liquid in the upper guard;
- and
- monitoring the boil-off gas flow rate from the test chamber until the boil-off gas flow rate is substantially stable.
Dependencies are inferred from the claim text.