Introduction; General; Application - Fluke 5624 User Manual

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Introduction

2.1

General

The Hart Platinum Resistance Thermometer (PRT) model 5624, is designed to
be the best secondary standard interpolating instrument converting temperature
to resistance up to 1000°C. The PRT is used with a readout device to detect
temperature changes or actual temperature. The PRT covers the International
Temperature Scale of 1990 (ITS-90) range from 0°C to 1000°C. The standard
resistance value is 10 ohms. The standard length is 20 inches. Custom lengths
are available on request.
The PRT is hand constructed at Hart Scientific by experts with years of PRT
manufacturing experience. Each PRT is carefully annealed at the appropriate
temperatures and precisely tested for stability. The sensing element is fabri-
cated using high purity platinum wire wound in a strain free design on a spe-
cially designed support. The 1/4 inch O.D. Alumina sheath is sealed with a
specially mixed gas and fit with a terminal box handle and strain relieved con-
nection to the four-wire cable. Gold plated spade lugs terminate the wires.
2.2

Application

Hart 5624 thermometer is classified as a secondary standard. A secondary stan-
dard is defined in terms of transfer of the ITS-90 from a standards laboratory to
a customer's laboratory. Secondary standards are calibrated using a primary
standard that has been calibrated in a primary calibration laboratory using
known intrinsic values.
Figure 1 Hart Model 5624 Platinum Resistance Thermometers
2 Introduction
General
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