Setra's MicroCal Features NASA Patented Technology
Scientists at Kennedy Space Center work in cleanrooms, laboratories with high degrees of cleanliness provided by strict control of particles such as dust, lint, or human skin. They are contaminant-free facilities, where the air is repeatedly filtered, and surfaces are smooth to prevent particles from getting lodged. Technicians working in these environments wear specially designed cleanroom “bunny suits” and booties over their street clothes, as well as gloves and face masks to avoid any contamination that may be imparted from the outside world. Even normal paper is not allowed in cleanrooms—only cleanroom low particulate paper. These are sensitive environments where precision work, like the production of silicon chips or hard disk drives, is performed.
Often in cleanrooms, positive air pressure is used to force particles outside of the isolated area. The air pressure in the Kennedy cleanrooms is monitored using high-accuracy, low-differential pressure transducers that require periodic calibration. Calibration of the transducers is a tricky business. In prior years, the analysis was performed by sending the transducers to the Kennedy Standards Laboratory, where a very expensive cross-floated, labor intensive, dead-weight test was conducted.
In the early 1990s, scientists at Kennedy determined to develop a technique and test equipment to perform qualification testing on new low-differential pressure transducers in an accurate, cost-effective manner on site, without requiring an environmentally controlled room. They decided to use the highly accurate, cost-effective Setra Model C264 differential pressure transducer for their testing. For qualification testing of the Setra C264, though, a portable, lower cost calibrator was needed that could control the differential pressure to a high degree of resolution and transfer the accuracy of the Standards Laboratory into the qualification testing. The researchers decided that to generate the low-differential pressure setpoints needed for qualification testing, very small gas volume changes could be made against the test article, and a corresponding pressure change would be detected by a pressure standard. This allowed the researchers to recreate cleanroom air pressure settings without the use of a cleanroom. By 1995, the prototype was perfected into the unit that is still used today, the MicroCal.
CLICK HERE to read more about how NASA's technology is incorporated into Setra's MicroCal.