A pressure-controlled heat pipe (PCHP) calibrator is on its way to a German government calibration institution. The calibration product from Advanced Cooling Technologies (ACT), Lancaster, Pa., will be used to standardize up to five thermometers to a reference thermometer.
The PCHP calibrator has a sodium heat pipe with the ability to operate between 1112 and 1832°F (600 and 1,000°C). It maintains a temperature stability of ±5 mK over a two-hour period. The device has six thermowells located within the vapor space of the heat pipe, maintaining a high degree of temperature uniformity between the thermometers. The transient stability of the heat pipe is maintained by actively controlling the pressure of the heat pipe’s vapor space, ensuring a stable saturation temperature within the heat pipe. The pressure is manipulated by changing the effective volume of the heat pipe, simply by moving a sealed bellows.
The pressure-controlled heat pipe technology was initially developed on a NASA Goddard Phase II Small Business Innovative Research (SBIR) program several years ago, demonstrating temperature stability in a low temperature spacecraft PCHP under varying power and sink conditions.
According to Dr. Richard Bonner, manager of customer products at ACT, translating results from aerospace research and development to high temperature calibration products presented a challenge. He attributed the project’s success to the collaboration between research and development and product development personnel.