Recent testing in a cylindrical, comparative cryostat at the Cryogenics Test Laboratory focused on various seam concepts for multilayer insulation systems. Three main types of seams were investigated: straight overlap, fold‐over, and roll wrapped. Each blanket was composed of 40 layer pairs of reflector and spacer materials. The total thickness was approximately 12.5 mm, giving an average layer density of 32 layers per centimeter. Test results show that all three seam concepts are all close in thermal performance; however, the fold‐over method provides the lowest heat flux. For the first series of tests, seams were located 120 degrees around the circumference of the cryostat from the previous seam. This technique appears to have lessened the degradation of the blanket due to the seams. In a follow‐on test, a 20 layer blanket was tested in a roll wrapped configuration and then cut down the side of the cylinder, taped together, and retested. This test result shows the thermal performance impact of having the seams all in one location versus having the seams clocked around the vessel. This experimental investigation indicates that the method of joining the seams in multilayer insulation systems is not as critical as the quality of the installation process.

Topics
Thermodynamic states and processes, Cryogenics, Educational assessment
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© 2010 American Institute of Physics.
2010
American Institute of Physics