초록 ▼

A test apparatus and method of its use for evaluating various performance aspects of a test specimen is disclosed. A chamber within a housing contains a cold mass tank with a contact surface in contact with a first surface of a test specimen. The first surface of the test specimen is spaced from the

A test apparatus and method of its use for evaluating various performance aspects of a test specimen is disclosed. A chamber within a housing contains a cold mass tank with a contact surface in contact with a first surface of a test specimen. The first surface of the test specimen is spaced from the second surface of the test specimen by a thickness. The second surface of the test specimen is maintained at a desired warm temperature. The first surface is maintained at a constant temperature by a liquid disposed within the cold mass tank. A boil-off flow rate of the gas is monitored and provided to a processor along with the temperature of the first and second surfaces of the test specimen. The processor calculates thermal insulation values of the test specimen including comparative values for heat flux and apparent thermal conductivity (k-value). The test specimen may be placed in any vacuum pressure level ranging from about 0.01 millitorr to 1,000,000 millitorr with different residual gases as desired. The test specimen may be placed under a mechanical load with the cold mass tank and another factors may be imposed upon the test specimen so as to simulate the actual use conditions.

대표청구항 ▼

1. A test apparatus for evaluating thermal properties of a test specimen, comprising:a chamber;a cold mass tank located within the chamber, said cold mass tank having a cavity adaptable for receiving a quantity of liquid, said cold mass tank also having a contact surface adaptable for contacting a f

1. A test apparatus for evaluating thermal properties of a test specimen, comprising:a chamber;a cold mass tank located within the chamber, said cold mass tank having a cavity adaptable for receiving a quantity of liquid, said cold mass tank also having a contact surface adaptable for contacting a first side of the test specimen positioned within said chamber, with the chamber having a contact surface adaptable for contacting a second, oppositely disposed side of the test specimen;a quantity of bulk insulation material surrounding the cold mass tank;a passageway assembly extending through the chamber, bulk insulation material and into the cold mass tank for introducing a quantity of liquid fluid into the cold mass tank and subsequently expelling boiled-off gas from the cold sass tank cavity, whereby the thermal performance of the test specimen is determined; anda plurality of spaced-apart and parallel extending compression rod assemblies located within the chamber, each compression rod assembly comprising an elongated spring rod and an elongated extension tube having confronting end portions extending within a connecting sleeve and engaging opposite ends of a compression spring, wherein each compression rod assembly is disposed such that one end portion engages the chamber and an opposite end portion engages the cold mass tank for pressing the cold mass tank against the specimen with a predetermined and controllable level of force. 2. The test apparatus of claim 1, further including a sensor assembly electronically connected to a processor capable of collecting sensor data measuring properties indicative of thermal properties of the test specimen. 3. The test apparatus of claim 2, wherein the sensor assembly includes at least one first temperature sensor in contact with the first side of the test specimen and at least one second temperature sensor in contact with the second side of the test specimen. 4. The test apparatus of claim 2, further comprising a processor in communication with the sensor assembly for calculating at least one thermal characteristic of the test specimen. 5. The test apparatus of claim 2, wherein the sensor assembly further comprises at least one sensor in fluid communication with the liquid fluid in the cold mass tank and in electronic connection with the processor. 6. The test apparatus of claim 1, further comprising a heater disposed to provide heat to the contact surface of the chamber, whereby heat travels from the chamber, through the test specimen and serves to heat the liquid located in the cold mass tank. 7. The test apparatus of claim 1, wherein the chamber is a vacuum chamber having an air-tight barrier adaptable for maintaining a chamber pressure between about 0.01 and 1,000,000 millitorr. 8. The test apparatus of claim 1, further comprising a vacuum port equipped with a filter assembly having a base with an O-ring forming a seal intermediate the vacuum port and the base, and filter media extending from the base having a first layer of fine filter media and a second layer of coarse filter media, wherein fluid communication through the base into the chamber requires passage through at least a portion of the filter media. 9. The test apparatus of claim 1, further comprising at least one edge guard positioned within the chamber, extending through a portion of the bulk insulation material and at least partially encircling the cold mass tank. 10. The test apparatus of claim 1, wherein the passageway assembly comprises a single feed-through bore extending through aligned openings in the chamber, the bulk insulation material and the cold mass tank cavity for providing the only passageway adaptable for introducing liquid fluid into the cold mass cavity and for venting boil-off gas exiting from the cold mass cavity. 11. The test apparatus of claim 1, wherein the liquid fluid is a cryogenic liquid. 12. The test apparatus of claim 1, further comprising a load cell located between the test specimen and wall of the chamber for measuring the pressure imposed by the at least one compression rod assembly against the test specimen. 13. The test apparatus of claim 1, wherein the bulk insulations material comprises a hydrophobic material enclosing the cold mass tank and contacting an edge portion of the test specimen. 14. The test apparatus of claim 13, wherein in the bulk insulation material is low outgassing, reusable and creates minimal dusting. 15. A method of measuring the thermal characteristic of a test specimen, comprising the following steps of:(a) placing a test specimen having first and second oppositely disposed surfaces within a vacuum chamber;(b) positioning a cold mass tank having a cavity within the chamber so that a contact surface boundary of the cold mass tank cavity engages the second surface of the test specimen;(c) compressing a plurality of spaced-apart and parallel extending compression rod assemblies between the chamber and the cold mass tank with each compression rod assembly comprising a compression rod and an extension tube having confronting ends extending within a connecting sleeve and engaging opposite ends of a spring for pressing the cold mass tank against the test specimen with a predetermined and controllable level of force;(d) surrounding the cold mass tank with a quantity of bulk insulation material;(e) heating the first surface of the test specimen;(e) filling the cold mass tank cavity with a liquid fluid;(f) completely venting all boiled-off gases from the cold mass tank cavity; and(h) measuring the steady state heat transfer through the test specimen between the first and second surfaces. 16. The method of claim 15, further comprising the step of measuring a value of the liquid fluid in the cold mass tank and utilizing the value to provide the insulation value of the test specimen. 17. The method of claim 15, further comprising the step of drawing and measuring a cold vacuum pressure in the vacuum chamber. 18. The method of claim 15, further comprising the step of applying a specific gaseous environment in the chamber. 19. The method of claim 15, including the further step of filling the cold mass tank cavity with a cryogenic liquid. 20. The method of claim 15, including the further step of filling the cold mass tank with liquid nitrogen. 21. The method of claim 15, including the further step of maintaining the cold mass tank contact surface at a steady state temperature of approximately 80 K. 22. The method of claim 15, including the further step of applying a vacuum to the chamber of approximately 1×10 − 5 torr.