Improvement Study on the Use of Dry-Well Calibrators for PRT Calibration

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Improvement Study on the Use of Dry-Well Calibrators for PRT Calibration (542.55 KB)

Radial and axial temperature gradients in the block and instability and hysteresis of the control sensor are main deficiencies that affect the performance of dry-well (block) calibrators. These inherent limitations are inevitable in a dry-well calibrator with single-zone control. In order to reduce calibration errors and improve the performance of dry-well calibrators, a new dry-well calibrator with dual-zone control, called “Metrology Well Calibrator,” was developed at Fluke- Hart Scientific. The performance of the new dual-zone dry-well calibrator was evaluated.

The axial temperature uniformity was measured using a specially made platinum resistance ther-mometer. The special PRT has a very short sensor within a platinum capsule, but no sheath. It is an excellent probe for measuring vertical temperature uniformity. The design of this PRT will be described briefly.

Several PRTs with different structures were calibrated at fixed points and then tested in the dual-zone Metrology Well Calibrator to identify measurement errors. The results will be reported.