Folie 1

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1 度量 Measurement of Temperature

2 Liquid-in-Glass Thermometer Resistance Thermometry Resistance Temperature Detector (RTD) Thermistor Thermoelectric Thermometry Seebeck Effect Peltier Effect Thomson Effect Optical Pyrometer Temperature Sensitive Liquid Crystal Display

3 參料 [1] 量度 2004 [2]Benedict, R. P., Fundamentals of Temperature, Pressure, and Flow Measurements, John Wiley & Sons, Inc., [3]Bevington, P. R., Data reduction and error analysis for the physical sciences, McGRAW-HILL Book Company, [4]Gennes, P. G. and Prost, J., The Physics of Liquid Crystals, ISBN= , Oxford Science Publications, [5] 金雷 - 理 2003

4 度 Temperature

5 度冷度數度度念了力力度裡不力

6 C : Celsius : Fahrenheit F K R Unit : Absolute : Rankine R ' : Reaumur Boiling Point Freezing Point

7 度理度 ( 度 ) 力 (TLCD) (RTD) 度

8 Liquid-in-Glass Thermometer

9 Liquid-in-Glass Thermometer - 1 利度冷度精度便行度量

10 Liquid-in-Glass Thermometer - 2 力度冷力

11 Controlling Switch

12 Discrete Switch

13 Continue Switch

14 Switch - Controller 利不金數度

15 Mechanical Pressure Transducers

16 Bourdon Tube

18 Bellows Gauge

19 Immersion Effect

20 Immersion Effect - 1

21 Immersion Effect - 2

22 Stem Corrections Most liquid-in-glass thermometers in use are of the total immersion type. This is because ambient temperature variations can introduce large uncertainties in the indications of partial immersion thermometers.

23 Stem Corrections - 1

24 Stem Corrections - 2

25 Stem Corrections - 3

26 例 1 練

27 例 1 練

28 Resistance Thermometry

29 Resistance Thermometer - 1 R T = f( T) R: Resistance = f( R) Ohm s Law: V = T: Temperature Resistance thermometers provide absolute temperatures in the sense that no reference junctions are involved, and no special extension wires are needed to connect the sensor with the measuring instrument. The three s s that characterize resistance thermometers are simplicity of circuits, sensitivity of measurements, and stability of sensors. IR

30 Resistance Thermometer - 2

31 練量行

32 Sensor

33 RTD Sensor The RTD s are electrical circuit elements formed of solid conductors (usually in wire form) which are characterized by a positive coefficient of resistivity. It is interesting to note in this regard that there is a direct relation between the temperature coefficient of resistivity of metals and the coefficient of expansion of gases. The RTD s of general usage are of platinum, nickel, and copper.

34 Platinum Sensor - 1

35 Platinum Sensor - 2

36 Nickel and Copper Sensor

37 連

38 連 Resistors in Series Resistors in Parallel Wheatstone Bridge

39 UC = mgh mg H C h mg B mg A U B = U A = mgh 0 U = U U CB C B = mgh mgh = mg( H h)

40 V a R V b + - a b i : Va, Vb ( ): Vab = Va Vb Ohm s Law V ab = ir 2 2 ab P= iv = i R= ab V R V ab i R P : Potential : Current : Resistor : Power

41 i Va Resistors in Series R1 R2 R3 V1 V2 V3 RN 串聯流 = 流 = ab j= 1 VN Vb V = V + V + V + + V = ir ( + R+ R+ + R ) = ir R= R + R + R + + R N = R j N N N i

42 Resistors in Parallel i Va i 1 i 2 i 3 i N R 1 R 2 R 3 R N Vb 聯流 = 流 = i i = i + i + i + + i j= = Vab( ) R R R R = Vab R = R R R R R N = 1 R j N N N

43 Wheatstone Bridge

44 Wheatstone Bridge Null Measurement Circuit: V x = 0

45 i 1 i 2 V s V s 1 1 Mathematics V s V1 = R R + R V2 Vs = R R + R 2 2 x u V = V V = V V = = R 2 1 R 1 = Vs = R1 + R R 2 = Vs = R2 + Ru 1 2 Vx V1 V2 Vs R1+ R R2 + Ru R R R = R u R 1 2 Vs R 1+ R 1 Vs R 1+ R u 2

46 I A VA Wheatstone Bridge V C R1 R2 R3 R4 V D I C VB I B V CD V = V V = V AB AB A B V = V A V = V V = I R AD A D A V = V V = I R B BD B D B 0 V = V V = I R AC A C A V = V V = I R BC B C B I R A I R A = 3 B 4 = I R I R 1 B I D RR = RR

47 Circuits and Bridges Variable Resistance ( ) Constant Resistance ( )

48 Variable Resistance

49 R 3 V out = 0 行量不易行不度量 R RTD RR = RR RTD

50 V out R 2 = R R + R R + R 3 RTD V in V out = 0 R2 R3 = R + R R + R RTD RR = RR RTD

51 Constant Resistance

52 V in 量易行不度量 R RTD

53 V out R R R3 R + R R + R 2 = RTD R RTD 3 = R2 V R + R V 1 2 out in V R 3 in R (1 ) RTD = R +α 0 t t = RRTD α R 0 R 0

54 練 ( t V out ) R RTD

55 練 V out R R3 R + R R + R 2 = t R (1 ) RTD = R0 +αt = RRTD α R 0 R 0 RTD V in t = R RTD 1 2 R 3 = R 3 R2 V R + R V R2 V R1+ R2 V out in α R 0 R out in R 3 0 R 3 t = C t V out = Vout

56 練

57 Three Cases Case1: R1 = R2 = R3 = 100Ω Case2: Case3: t V out = Vout R1 = R2 = R3 = 10kΩ t V out 1 = Vout R = 100 Ω, R = R = 10kΩ V out t = *100

58 Three Cases

59 Case3 路 C = Vout Case2: 1 V out Case3: V 2 20 out

60 Calibration Curves

61 Case3 路 V out 10k 10k = k 10k+ 2r+ RRTD

62 Case3 路 r = 10Ω 0 C V out 10k 10k = = 0.391V k 10k t = 51.7 C Case3 路度

63 Siemens 3-Wires RTD V r V out 10k 10k = ( 10 V ) r k+ r 10k+ RRTD + r

64 V in -1 V in 量數路來量量

65 V in -1 來 V out R R3 R + R R + R 2 = RTD V in V out R R 2 3 = R1+ R2 R3 + RR Cal V in R 利量 V R Cal Vin out 行量 V in

66 V in -2 V in 量路來量量 RR adj V 行量 in

68 Thermistor

69 Thermistor Temperature sensitive resistor materials (such as metallic oxides) Typical thermistor resistance variations are from 50,000 Ω at 100 F to 200 Ω at 500 F. Their characteristic temperature-resistance relationship can be approximated by a power function of the form b R = ae T R: thermistor resistance at its absolute ambient temperature T. a and b: constants with typical values of 0.06 and 8000.

70 Thermistor

71 Thermistor Negative Temperature Coefficient (NTC) Positive Temperature Coefficient (PTC) Critical Temperature Resistor (CTR)

72 Thermistor

73 NTC NTC

74 Thermistor

75 Thermistor

76 Thermistor

77 Thermistor

78 Thermoelectric Thermometry

79 Seebeck Effect

80 (Seebeck Effect) Seebeck Effect 兩不金料 (A, B) 連路兩兩不度路流 Q A T 2 emf ( ) AB, = Q T A QB dt 1, Q B : A, B 兩金數

81 Peltier Effect 兩不金料 (A, B) 連路兩路流兩

82 Peltier Effect A B i A B i dqp = ±π Idθ π : Peltier Coefficient or Peltier Voltage.

83 Thomson Effect 金料度度金料流流

84 Seebeck Effect Peltier Effect Thomson Effect 說不金料路度流不金料路流金料度度流

85 Thermoelectric Cooling

86 Stirling Refrigerator

87 Refrigerator Warm Reservoir Condenser Liquid Storage Refrigerant Compressor Isothermal und isobar Condensation Adiabatic Compression Throttling Valve Evaporator Refrigerant Expansion Isothermal and isobar Evaporation Cold Reservoir

88 Air Condition

89 Thermoelectric Cooling 冷 T 1 B i A B T 0

90 Thermoelectric Cooling 冷 DC 兩不料流兩不料兩料不冷不冷流來冷

91 Thermoelectric Cooling 160 年例冷 (1) 率 (2) 力 (3) 冷度 ( 0 C) 率流流

92 Thermoelectric Law

93 Thermoelectric Law Law of Homogeneous Circuit Law of Intermediate Metals Law of Intermediate Temperature

94 Law of Homogeneous Circuit 金兩兩度度

95 Law of Homogeneous Circuit

96 Law of Intermediate Metals 金金不兩 P,Q 兩度狀兩

97 Law of Intermediate Metals

98 Law of Intermediate Temperature 金路兩度度 T1 T3 E3 T1 T2 E1 T2 T3 E2

99 Law of Intermediate Temperature

100 Thermocouple

101 Thermocouple 利律來量度金來行量量冷參

102 Thermocouple Types S-Type: A thermocouple best suited for measurements in the 400 to 1760 degree (C) range. R-Type: A thermocouple best suited for measurements in the 300 to 1760 degree (C) range. J-Type: A thermocouple best suited for measurements in the 0 to 480 degree (C) range. The positive conductor is made of iron, and the negative conductor is made of constantan. K-Type: A thermocouple best suited for measurements in the 0 to 480 degree (C) range. The positive conductor is made of chromel, and the negative conductor is made of alumel.

103 Thermocouple Types T-Type: A thermocouple best suited for measurements in the -200 to 0 degree (C) range. The positive conductor is made of copper, and the negative conductor is made of constantan. E-Type: A thermocouple best suited for measurements in the 0 degree to 480 degree (C) range. The positive conductor is made of chromel and the negative conductor is constantan. B-Type: A thermocouple best suited for measurements in the 1100 to 1820 degree (C) range.