真空绝热板出厂质量控制的快速无损热检测

Thermal conductivity is a critical thermophysical property to be measured during the production of vacuum insulation panels (VIP). In the past quality control testing has been limited to guarded hot plate testing, however this method is not only time consuming, but also has size constraints where a sample must be “mocked up” in order to evaluate. A fast, new and non-destructive instrument for evaluating the thermal conductivity of encapsulated materials has been developed without sample preparation or sample size constraints. This study focused on optimizing the instruments three critical parameters: start time, test time and cooling time. Dozens of combinations were tried in order to determine the best testing protocol for quickly and efficiently screening panels on a pass/fail basis. A criterion for the pass/fail line was based on the need for low initial internal pressure in VIPs for appliance use to insure long effective life. The test parameters that resulted from the optimization step allow for a maximum of 4000 panels per month to be tested, given a two shift working schedule. This results in a test cycle times of less than one minute.