上游充通大粤 SHANGHAI JIAO TONG UNIVERSITY Lecture 16 Temperature Measurement 通 Jiangi Sun a SHANG 1日日日 ERSITY
Lecture 16 Temperature Measurement Jianqi Sun
上游充通大？ SHANGHAI JIAO TONG UNIVERSITY Outline 0.What is temperture 1.Liquid-in-glass thermometres 2.Resistive Temperature Detectors (RTD) 3.Thermistor 4.Thermalcopules 5.Fiber Optic Thermometers 6.IR-thermometres 7.Summary and Other measurement methods
Outline 0. What is temperture 1. Liquid-in-glass thermometres 2. Resistive Temperature Detectors (RTD) 3. Thermistor 4. Thermalcopules 5. Fiber Optic Thermometers 6. IR-thermometres 7. Summary and Other measurement methods
上游充通大粤 SHANGHAI JIAO TONG UNIVERSITY Temperature © Particles are always moving. © When you heat water,the water molecules move faster. When molecules move faster,the substance gets hotter. © When a substance gets hotter,its temperature goes up
Temperature Particles are always moving. When you heat water, the water molecules move faster. When molecules move faster, the substance gets hotter. When a substance gets hotter, its temperature goes up
图 上游充通大 SHANGHAI JIAO TONG UNIVERSITY Temperature Scales Absolute Temperature (Kelvin) Practical scale (Celsius scale,Fahrenheit)
Temperature Scales Absolute Temperature (Kelvin) Practical scale (Celsius scale, Fahrenheit)
上游充通大粤 SHANGHAI JIAO TONG UNIVERSITY Temperature Scales Fahrenheit( Celsius Kelvin Nater boils212°F 100°C 373K Water freezes32°F 0°C 273K F=9/5C+32
Temperature Scales Fahrenheit Celsius Kelvin Water boils 212°F 100°C 373 K Water freezes 32°F 0°C 273 K F=9/5C + 32
上海充通大学 Liquid-in-glass,the basics SHANGHAI JIAO TONG UNIVERSITY ©How it works: volume change. V=V(1+Y1) © Make up: Mercury ·Ethyl alcohol ·Kerosene. Temperature range: 。 56765422 Mercury ·-38Cto356C Ethyl alcohol ● low temperature (down to-200C) Liquid-in-glass
Liquid-in-glass, the basics How it works: • volume change. Make up: • Mercury • Ethyl alcohol • Kerosene. Temperature range: • Mercury • -38 oC to 356 oC • Ethyl alcohol • low temperature (down to -200 oC) Liquid-in-glass 0 VV T = + (1 ) γ
上游充通大￥ SHANGHAI JIAO TONG UNIVERSITY Liquid-in-glass Advantages and Disadvantages 图Advantages: 国 Disadvantages: ·Low cost 。Limited measuring 。Linear range due to the ·Easy to use quality of glass and characteristic of the 。Simple structure measuring medium Brittle
Liquid-in-glass Advantages and Disadvantages Advantages: • Low cost • Linear • Easy to use • Simple structure Disadvantages: • Limited measuring range due to the quality of glass and characteristic of the measuring medium • Brittle
上游充通大粤 SHANGHAI JIAO TONG UNIVERSITY Resistive Temperature Detectors (RTD),the basics ©How it works: 0 Utilizes the fact that resistance of a metal changes with temperature. 国 Make up: Traditionally made up of platinum,nickel,iron or copper wound around an insulator. Temperature range: From about-196°Cto 482°C. Thin Film RTD R(t)/R(0)=1+aT+bT2
Resistive Temperature Detectors (RTD), the basics How it works: • Utilizes the fact that resistance of a metal changes with temperature. Make up: • Traditionally made up of platinum, nickel, iron or copper wound around an insulator. Temperature range: • From about -196 °C to 482 °C. Thin Film RTD R ( t)/ R(0) = 1 + a T + bT2
上游充通大粤 SHANGHAI JIAO TONG UNIVERSITY RTD Advantages and Disadvantages Advantages: ©Disadvantages: 。Stable ·Expensive ·Very accurate Current source Change in required resistance is linear Small change in resistance 。Self heating Less rugged than thermocouples
RTD Advantages and Disadvantages Advantages: • Stable • Very accurate • Change in resistance is linear Disadvantages: • Expensive • Current source required • Small change in resistance • Self heating • Less rugged than thermocouples
上游充通大学 Thermistor,the basics SHANGHAI JIAO TONG UNIVERSITY ©How it works: ·Like the RTD a thermistor uses the fact that resistance of a semiconductor I changes with temperature. ©Make up: e Generally made up of semiconductor materials Temperature Range: ·Ab0ut-45°C-150°C Thermistor
Thermistor, the basics How it works: • Like the RTD a thermistor uses the fact that resistance of a semiconductor l changes with temperature. Make up: • Generally made up of semiconductor materials Temperature Range: • About -45 °C - 150 ° C Thermistor
