วรุตม์ เกียรติธนะบำรุง 5030475821 Calibration of Thermocouple ปวีร์ ภัทรดิลก 5030314421 พบพงศ์ เลิศชยานันท์ 5030345921 วรุตม์ เกียรติธนะบำรุง 5030475821 วสวัตติ์ รอดจั่น 5030482121 อุกฎษฎ์ สุวรรณกูฎ 5030626221

Objective To gain some understanding on the theory underlying the thermoelectric temperature measurement, especially thermocouples and develop some expertise in the measurement of temperature with thermocouples. To gain understanding on the concept of calibration and basic process of calibrating an instrument. Specifically to realize the purpose of calibration, why an instrument should be calibrated before use.

(electromotive force) emf What is Thermocouple ? A thermocouple is a junction formed from two different metals that produces a voltage when subjected to a temperature difference. Thermocouples are a widely used type of temperature sensor. thermocouple The temperature difference DT is converted to voltage (electromotive force) Voltage (electromotive force) emf

Functional form Where : is the type of thermocouple. is the temperature at measuring junction of the thermocouple. is the temperature at the reference junction is the electromotive force (voltage).

Type of Thermocouples Type Materials Temperature Range Sensitivity E Chromel (Ni-Cr) & Constantan (Cu-Ni) -270 to 1000°C 60.9 μV/°C J Iron & Constantan (Cu-Ni) -210 to 1200°C 51.7 μ V/°C K Chromel (Ni-Cr) & Alumel (Ni-Al) -270 to 1350°C 40.6 μ V/°C T Copper & Constantan (Cu-Ni) -270 to 400°C R Platinum & 87%Platinum -50 to 1750°C 6 μ V/°C S 90% Platinum & 10% Rhodium B 94% Platinum & 6% Rhodium

การทดลอง

Equipment Voltmeter Hot Bath

The experiments Finding relation between Record the voltage of each thermocouple from 3 - 62 °C Tref Tmes Hot bath

ผลการทดลอง

Uncetainty(@95%Confidence) Thermocouple Type J Temperature (°C) Thermocouple Ref. Table Calibration Result Voltage (mV) Average Voltage (mV) SD Uncetainty(@95%Confidence) 1st 2nd 3 0.151 0.11 0.10 0.105 0.00707 0.06353 6 0.303 0.20 0.26 0.230 0.04243 0.38119 9 0.456 0.37 0.43 0.400 12 0.609 0.52 0.57 0.545 0.03536 0.31766 15 0.762 0.69 0.75 0.720 18 0.916 0.85 0.90 0.875 21 1.071 1.01 1.07 1.040 24 1.226 1.17 1.22 1.195 27 1.381 1.32 1.38 1.350 30 1.537 1.50 1.54 1.520 0.02828 0.25412 33 1.693 1.64 1.70 1.670 36 1.849 1.81 1.86 1.835 39 2.006 1.97 2.02 1.995 42 2.164 2.13 2.18 2.155 45 2.322 2.28 2.35 2.315 0.04950 0.44472 48 2.480 2.47 2.51 2.490 51 2.638 2.62 2.67 2.645 54 2.797 2.78 2.85 2.815 57 2.956 2.95 3.00 2.975 60 3.116 3.10 3.16 3.130

Graphical Presentation

Thermocouple Ref. Table Calibration Result Voltage (mV) Thermocouple Type K Temperature (°C) Thermocouple Ref. Table Calibration Result Voltage (mV) Average Voltage (mV) SD Uncetainty(@95%Confidence) 1st 2nd 4 0.158 0.08 0.06 0.070 0.01414 0.12706 7 0.277 0.20 0.16 0.180 0.02828 0.25412 10 0.397 0.31 0.33 0.320 13 0.517 0.45 0.450 0.00000 16 0.637 0.56 0.560 19 0.758 0.69 0.70 0.695 0.00707 0.06353 22 0.879 0.81 0.77 0.790 25 1.000 0.93 0.95 0.940 28 1.122 1.07 1.070 31 1.244 1.18 1.20 1.190 34 1.366 1.31 1.33 1.320 37 1.489 1.43 1.45 1.440 40 1.612 1.53 1.530 43 1.735 1.68 1.66 1.670 46 1.858 1.79 1.82 1.805 0.02121 0.19059 49 1.982 1.93 1.95 1.940 52 2.106 2.04 2.06 2.050 55 2.230 2.16 2.19 2.175 58 2.354 2.29 2.31 2.300 61 2.478 2.40 2.45 2.425 0.03536 0.31766

Graphical Presentation

Uncetainty(@95%Confidence) Thermocouple Type T Temperature (°C) Thermocouple Ref. Table Calibration Result Voltage (mV) Average Voltage (mV) SD Uncetainty(@95%Confidence) 1st 2nd 5 0.195 0.11 0.16 0.135 0.03536 0.31766 8 0.312 0.23 0.29 0.260 0.04243 0.38119 11 0.431 0.33 0.41 0.370 0.05657 0.50825 14 0.549 0.48 0.53 0.505 17 0.669 0.59 0.65 0.620 20 0.790 0.72 0.77 0.745 23 0.911 0.84 0.88 0.860 0.02828 0.25412 26 1.033 0.96 1.01 0.985 29 1.155 1.09 1.13 1.110 32 1.279 1.20 1.26 1.230 35 1.403 1.34 1.38 1.360 38 1.528 1.46 1.52 1.490 41 1.654 1.58 1.63 1.605 44 1.780 1.70 1.75 1.725 47 1.908 1.83 1.89 1.860 50 2.036 1.96 2.01 1.985 53 2.165 2.07 2.14 2.105 0.04950 0.44472 56 2.294 2.20 2.27 2.235 59 2.425 2.34 2.40 2.370 62 2.556 2.50 2.51 2.505 0.00707 0.06353

Graphical Presentation

Graphical Presentation Note : For distinct graphical presentation, error bars are not shown.

Experimental Results -The calibration curves of the T vs emf(voltage) is linear. -Level of error is low. -Slope of calibration curve of type J is more than type K and type T.

สรุปผลการทดลอง

Conclusion 1.ผลการทดลองที่ได้จากการ Calibrate มีค่าใกล้เคียงกับ Revised Thermocouple Reference Tables 2.Electromotive Force กับอุณหภูมิที่แตกต่างมีความสัมพันธ์กันเป็นเส้นตรง 3.Thermocouple Type J มี Sensitivity มากกว่า Type K,T

Appendix

Calculation of Uncertainty Since the information of the voltmeter and hot bath are unknown, so Let And, So, Note : For and @ 95% confidence : ** ** Reference : Inverse Student t Distribution; “Some Aspect of Experimentation”,2103-390 Mechanical Engineering Experimentation and Laboratory I, Asi Bunyajitradulya (Page 193).