Ch. 1

Temperature Scales and Classification of Thermometers Ch. 1

Contents Temperature Historical Background Thermodynamic Temperature Scale International Temperature Scale Classification of Thermometers

Historical Backgrounds of Temperature

Temperature 뜨겁거나차가운고체를만지거나가까이갈때의경험을통해생겨난개념 온도는 thermal energy 를측정하기위한척도 heat flow 를일으키는 force

The first thermometer 1592~1603, 갈릴레오에의해만들어짐 온도에따른기체부피의변화를이용 1) tube 안기체를데움 2) 기체가식으면서부피가줄어들어 liquid 를빨아올림

History 임의로 temperature scale 을나타냄 1669, H. Fabri 눈의온도, 가장더운여름날의온도 1693, Rinaldi and Padua 눈의녹는점 12 division 물의끓는점 1693, E.Halley 최초로 mercury 를 thermometric liquid 로사용 17 세기말 ~18 세기초, Romer 가장추운날씨의온도 0 사람의체온 24 물의끓는점 50~55 Fahrenheit scale 의기초 대부분기상목적을위한온도측정 고온에대한고려를하지않음

History 1724, Fahrenheit 당시가장추운날 0ºF 추운날의온도를음수로표현하지않기위해가장낮은기온을 0ºF 로잡고자했던것으로추정 가장더운날 100ºF 물의어는점 32ºF 사람체온 96ºF

History 1742, Celsius 물의어는점 100ºC 100 division 물의끓는점 0ºC Celsius 가죽고나서동료가 0ºC 과 100ºC 을뒤집음 고온가열기술의개발 1828, Prinsep Air thermometer using gold bulb 1000ºC 까지의온도를측정 1836, Pouillet Platinum bulb 를이용한고온측정온도계

Thermodynamic Temperature Scale ( 열역학적온도눈금 )

Temperature Scale Temperature fixed points e.g., 물의어는점, 끓는점, etc for defining interpolation between fixed points thermometric working substance e.g., mercury, alcohol, etc. Properties e.g., volume, weight, resistance, length, etc. correlating functions

표준온도눈금의필요성 각기다른온도의눈금 Problem! = 50ºC 50.7ºC

이상기체방정식 Thermometric working substance Ideal gas 계를구성하는입자의부피가거의 0 입자간상호작용이거의없어분자간위치에너지가중요하지않으며 분자간충돌이완전탄성충돌인가상의기체 Properties 온도에따른압력, 부피 Function P: pressure V: volume n: number of moles of gas k: Boltzman s constant, 1.3807 10-23 J/K PV=nkT

절대온도눈금 (K, thermodynamic temperature) 이상기체를기반으로모델링 OK 에서기체의부피가 0 1848, Kelvin 열에너지에대한정량적계산이가능 negative value 가없다. 열역학제 2 법칙, Carnot Engine 적용 1K TTTTTT ppppp oo wwwww 273.16

International Temperature Scale

For Temperature Scale Thermometric working substance Properties Correlating functions

History NHS ITS-27 ITS-48 IPTS-68 EPT-76 ITS-90, 현국제온도눈금

ITS-90

Classification of Thermometers

Temperature Chains Self-sustaining cross-converter extract energy during thermal energy different energy form Modulator requires external power source support the acquisition and flow of the temperature information

Classification of temperature sensors

Classification of temperature sensors

Classification of temperature sensors

Measuring ranges of temperature sensors

Non-electric Thermometers Ch. 2

Contents Liquid-in-Glass Thermometer Solid-Expansion Thermometers Manometer Thermometers Temperature Indicators

Liquid-in-Glass Thermometer

Liquid-in-Glass Thermometer GAS l θ = V = Vβ a θ β a = β l β g V πd 2 θ/4 = 4V bβ l β g πd 2 θ = β a n(θ i θ m ) V: vvvvvv vvvvvvvvv V b : bulk volume β a : aaaaaaa aaaaaaaa ccccccccccc oo ccccc ttttttt eeeeeeeee oo ttt tttttttttttt llllll β l : ccccccccccc fff llllll β g : ccccccccccc fff ggggg θ: mmmmmmmm ttttttttttt vvvvvvvvv θ i : the indicated temperature θ m : the average temperature of the emergent liquid column d: diameter of the inner capillary n : the length of the emergent liquid column

Other thermometers 메탈로보호

Solid-Expansion Thermometers Dilatation thermometers Bimetallic thermometers

Dilatation thermometers

Dilatation thermometers l = l 1 + α 1 θ l(1 + α 2 θ) = l(α 1 -α 2 ) θ α x : ttt ccccccccccc oo llllll ttttttt eeeeeeeee oo ttt mmmmmmmm x

Bimetallic thermometers

Bimetallic thermometers

Bimetallic thermometers

Manometer Thermometers Liquid-filled thermometers Vapour-pressure thermometers Gas thermometers

Liquid-filled thermometer

Liquid-filled thermometer

Vapor-pressure thermometers based on the temperature dependence of the saturated vapor pressure of the thermometric liquid Gas thermometers vapor-pressure thermometer structure with larger bulb using gas-pressure as a function of temperature

Temperature Indicators Pyrometric cones Thermochromic paints Temperature indicating crayons Self-adhesive indicators Liquid crystals

Pyrometric cones 요업관계의온도관리용으로만들어진온도센서 상응한온도에서연화하여쓰러짐 반응온도 : 600~2000, 10~30 간격

Thermochromic paints irreversible/reversible a function of the temperature a function of heating time

Temperature indicating crayons 표면온도를확인하기위해사용 Plate 및자재의예열및층간온도확인용 빠른온도측정이가능 within 1 or 2 seconds 65 ~ 670

Self-adhesive indicators 접착식 indicator the application of the thermochromic paints enable to apply to very small components e.g., transistors, integrated circuits, etc.

Liquid crystals 온도에따라다양한색으로변화 micro liquid crystals + 염료 paint the reflection wavelength is changed depends on the temperature high temp. the gap b/w the crystals is closer blue color low temp. the gap b/w the crystals is longer red color

Q&A