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Session:

1B - Temperature I 

Date & Time:

Monday August 7, 10:45 AM - 12:15 PM

Paper Title:

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

 

 

Speaker:

Mingjian Zhao, Director of Primary Satndard Engineering  

CoAuthors:

Mike Hirst, Rong Ding, and Deming Chen 

Speaker Info

Company:

Fluke-Hart Scientific

Address:

799 E Utah Valley Dr.
American Fork, UT, 84003-9775, United States

Phone:

801-763-1600

Fax:

801-763-1010

Email:

mingjian.zhao@hartscientiific.com 

 

 

Abstract:

Dry-well block calibrators are widely used as temperature standards or comparison apparatus in many secondary level calibration laboratories and in various industrial fields. Since dry-well (dry-block) calibrators are designed primarily for convenience and efficiency in a calibration process, a few inherent limitations are inevitable. In order to reduce calibration errors and improve the performance of dry-well calibrators, a new dry-well calibrator with dual-zone control was developed at Fluke Hart Scientific. The performance of the new dual-zone dry-well was evaluated. Horizontal and vertical temperature gradients in the block and stability and hysteresis of the control sensor are main deficiencies that affect the performance of dry-well calibrators. These characteristics were measured using a specially made platinum resistance thermometer. The special PRT has a very short sensor within a platinum capsule, but no sheath. It is an excellent probe for measuring vertical temperature gradients. The design of this PRT will be described briefly. Besides the inherent deficiencies of dry-well calibrators, correct use is also very critical to minimize calibration errors. Some common operational mistakes and measurement errors will be discussed. Based on the test results, a few methods to reduce the measurement errors will be introduced. Several PRTs with different structures were calibrated at fixed points and then tested in the dual-zone drywell to identify measurement errors. The results will be reported.  

 

 

 

 

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