1、MANUAL ON THE USE OF THERMOCOUPLES IN TEMPERATURE MEASUREMENT Fourth Edition Sponsored by ASTM Committee E20 on Temperature Measurement ASTM Manual Series:MNL 12 Revision of Special Technical Publication(STP)470B ASTM Publication Code No.(PCN):Library of Congress Cataloging-in-Publication Data Manua
2、l on the use of thermocouples in temperature measurement/sponsored by ASTM Committee E20 on Temperature Measurement.(ASTM manual series:MNL12)Revision of special technical publication(STP)470B ASTM Publication code no.(PCN):28-012093-40 Includes bibliographical references and index.ISBN 0-8031-1466-
3、4 1.ThermocouplesHandbools,manuals,etc.2.Temperature measurementsHandbooks,manuals,etc.I.ASTM Committee E20 on Temperature Measurement.II.Series.QC274.M28 1993 92-47237 536.52dc20 CIP Foreword The Manual on the Use of Thermocouples in Temperature Measurement was sponsored by ASTM Committee E20 on Te
4、mperature Measurement and was compiled by E20.94,the Publications Subcommittee.The editorial work was co-ordinated by R.M.Park,Marlin Manufacturing Corp.Helen M.Hoersch was the ASTM editor.Contents Chapter 1Introduction 1 Chapter 2Principles of Thermoelectric Thermometry 4 2.0 Introduction 4 2.1 Pra
5、ctical Thermoelectric Circuits 5 2.1.1 The Thermoelectric Voltage Source 5 2.1.2 Absolute Seebeck Characteristics 5 2.1.2.1 The Fundamental Law of Thermoelectric Thermometry 8 2.1.2.2 Corollaries from the Fundamental Law of.Thermoelectric Thermometry 10 2.1.2.3 The Seebeck EMF Cell 10 2.1.3 Inhomoge
6、neous Thermoelements 11 2.1.4 Relative Seebeck Characteristics 11 2.2 Analysis of Some Practical Thermoelectric Circuits 18 2.2.1 Example:An Ideal Thermocouple Assembly 21 2.2.2 Example:A Nominal Base-Metal Thermocouple Assembly 22 2.2.3 Example:A Normal Precious-Metal Thermocouple Assembly with Imp
7、roper Temperature Distribution 25 2.3 Historic Background 28 2.3.1 The Seebeck Effect 29 2.3.2 The Peltier Effect 30 2.3.3 The Thomson Effect 31 2.4 Elementary Theory of the Thermoelectric Effects 32 2.4.1 Traditional Laws of Thermoelectric Circuits 33 2.4.1.1 The Law of Homogeneous Metals 33 2.4.1.
8、2 The Law of Intermediate Metals 33 2.4.1.3 The Law of Successive or Intermediate Temperatures 33 2.4.2 The Mechanisms of Thermoelectricity 34 2.4.3 The Thermodynamics of Thermoelectricity 36 2.4.3.1 The Kelvin Relations 36 2.4.3.2 The Onsager Relations 38 2.5 Summary of Chapter 2 39 2.6 References
9、40 2.7 Nomenclature 41 Chapter 3Thermocouple Materials 43 3.1 Common Thermocouple Types 43 3.1.1 General Application Data 45 3.1.2 Properties of Thermoelement Materials 48 3.2 Extension Wires 51 3.2.1 General Information 51 3.2.2 Sources of Error 54 3.3 Nonstandardized Thermocouple Types 62 3.3.1 Pl
10、atinum Types 63 3.3.1.1 Platinum-Rhodium Versus Platinum-Rhodium Thermocouples 63 3.3.1.2 Platinum-15%Iridium Versus Palladium Thermocouples 65 3.3.1.3 Platinum-5%Molybdenum Versus Platinum-0.8%Cobalt Thermocouples 67 3.3.2 Iridium-Rhodium Types 68 3.3.2.1 Iridium-Rhodium Versus Iridium Thermocouple
11、s 68 3.3.2.2 Iridium-Rhodium Versus Platinum-Rhodium Thermocouples 3.3.3 Platinel Types 3.3.3.1 Platinel Thermocouples 3.3.3.2 Palladorl 3.3.3.3 Palladorll 3.3.4 Nickel-Chromium Types 3.3.4.1 Nickel Chromium Alloy Thermocouples 3.3.4.1.1 Geminol 3.3.4.1.2 Thermo-Kanthal Special 3.3.4.1.3 Tophel II-N
12、ial II 3.3.4.1.4 Chromel 3-G-345-Alumel3-G-196 3.3.5 Nickel-Molybdenum Types 69 71 71 73 74 75 75 75 75 75 77 78 3.3.5.1 20 Alloy and 19 Alloy(Nickel Molybdenum-Nickel Alloys)78 3.3.6 Tungsten-Rhenium Types 78 3.3.7 Gold Types 81 3.3.7.1 Thermocouples Manufactured from Gold Materials 81 3.3.7.2 KP o
13、r EP Versus Gold-0.07 Atomic Percent Iron Thermocouples 82 3.3.7.3 Gold Versus Platinum Thermocouples 83 3.4 Compatibihty Problems at High Temperatures 84 3.5 References 84 Chapter 4Typical Thermocouple Designs 87 4.1 Sensing Element Assemblies 88 4.2 Nonceramiclnsulation 88 4.3 Hard-FiredCeramiclns
14、ulators 93 4.4 Protecting Tubes,Thermowells,and Ceramic Tubes 95 4.4.1 Factors Affecting Choice of Protection for Thermocouples 95 4.4.2 Common Methods of Protecting Thermocouples 97 4.4.2.1 Protecting Tubes 97 4.4.2.2 Thermowells 98 4.4.2.3 Ceramic Tubes 98 4.4.2.4 Metal-Ceramic Tubes 98 4.5 Circui
15、t Connections 99 4.6 Complete Assemblies 100 4.7 Selection Guide for Protecting Tubes 100 4.8 BibUography 107 Chapter 5Sheathed,Compacted,Ceramic-Insulated Thermocouples 108 5.1 General Considerations 108 5.2 Construction 108 5.3 Insulation 110 5.4 Thermocouple Wires 112 5.5 Sheath 112 5.6 Combinati
16、ons of Sheath,Insulation,and Wire 112 5.7 Characteristics of the Basic Material 112 5.8 Testing 113 5.9 Measuring Junction 117 5.10 Terminations 122 5.11 Installation ofthe Finished Thermocouple 122 5.12 Sheathed Thermocouple Applications 122 5.13 References 124 Chapter 6Thermocouple Output Measurements 125 6.1 General Considerations 125 6.2 Deflection Millivoltmeters 125 6.3 Digital Voltmeters 126 6.4 Potentiometers 126 6.4.1 Potentiometer Theory 126 6.4.2 Potentiometer Circuits 127 6.4.3 Types