BS in Mechanical Engineering
Mechanical Engineering Department
There is a need for better HEPA filter materials, especially those able to withstand higher temperatures as experienced in fire conditions. In order to test these materials our team built a Mini High Temperature Testing Unit (MHTTU) that can rapidly, efficiently, and inexpensively test a large number of new and innovative materials for HEPA filter components. MHTTU test results will be used to down select the most promising materials for HEPA filter components (e.g., media, sealants, gaskets) for full scale testing in the HTTU. There are already some pieces of equipment that exist in other parts of the country that produce similar effects, but do not fulfil our specific needs of 1300°F air at the low flow rates of 1.25-12 ACFM. Our attempts to source heaters were iterative due to the difficult nature of finding items that fulfilled both extreme specifications.
The design decided upon pre-testing involved using two individually operating heaters, one for each end of flow regime. After initial testing, the immersion heater, originally intended solely for the low range of flows proved better able to handle our complete range than the higher flow heat torch. With the current design, we were only able to reach a temperature of 1116F, but we were able to meet all of our other specifications, including flow rates, warm up time, and differential pressure drop across the test section. We believe that the majority of our heat loss was shed through the uninsulated housing of the heat torch, and recommend removing the heat torch and transfer section from the device. This would lessen the mass of stainless steel to be heated as well as remove a relatively large heat shedding fin from the device.