Low drift Type K and N Mineral Insulated thermocouples for high temperature applications. Dr. Michele Scervini Trevor D Ford. CCPI Europe Limited

Transcription

1 Low drift Type K and N Mineral Insulated thermocouples for high temperature applications Dr. Michele Scervini Trevor D Ford

2 Agenda CCPI Europe Limited Introduction to Low Drift thermocouples Thermocouple Life v Thermocouple Effective Life Summary of Cambridge tests and initial CCPI tests Latest CCPI tests on dual wall MI cable Other tests (EMPRESS) The next step: Alternative geometry

3 Mineral Insulated Metal Sheathed (MIMS) thermocouples

4 CCPI Europe Limited An example of tolerance bands Correction values in C Temperature Correction Curve for Coil Temperature in C Mean BAC 5621 Tol ASTM E230 Special Tolerances IEC Class 1

5 CCPI Europe Limited Thermocouple Drift (1) Correction values in C Temperature Correction Curve for Coil After several hours of operation Temperature in C Mean BAC 5621 Tol ASTM E230 Special Tolerances IEC Class 1

6 CCPI Europe Limited Thermocouple Drift (2) Temp = 500 C Emf dt = S dx = E0 + E dx E n Ideal thermocouple output Time dependent metallurgical modifications: Oxidation Short range ordering Depletion/change in composition Other physical/chemical changes

7 Challenge to reduce Drift A- A Conventional MIMS (Mineral Insulated Metal Sheathed) TCs experience significant drift above 1000 C Mineral Insulator (Powder) A-A Wire 1 Wire 2 Sheath Improved temperature measurements are much needed for industrial applications: this led to a detailed investigation in to the specific causes of drift in mineral insulated thermocouples at the University of Cambridge. From this investigation a new design of thermocouple cable has been developed at the University of Cambridge

8 CCPI Europe Limited The new thermocouple Contamination from the sheath to the thermoelements is the major cause of drift in conventional MIMS The new sensor is based on new sheath Thermoelements Minimise contamination from sheath to thermoelements Thermoelements: flexibility to use type K, type N, Inner wall Outer wall Patent issued & pending

9 The life of TCs CCPI Europe Limited

10 The life of TCs: Effective Life

11 Drift tests:aisi C

12 Drift tests:aisi C

13 Drift tests AISI310: Summary 1200 C 400h (conventional TC) 1200 C 400h (new TC) 1300 C 150h (conventional TC) 1300 C 150h (new TC) Total Drift -15 C -2.5 C -31 C -2.5 C Validation of the concept the new sensor is based on 1200 C: Over 80% drift reduction 1300 C: Over 90% drift reduction Path for reliable Ni based sensor working up to 1300 C

14 Drift tests:inc C

15 Drift tests:inc C

16 Type N Drift tests: Summary 1200 C 400h (conventional TC) 1200 C 400h (new TC) 1300 C 100h (conventional TC) 1300 C 100h (new TC) Total Drift -6 C Within +1 C -2 C -14 C Validation of the concept the new sensor is based on 1200 C: Over 80% drift reduction 1300 C: Over 85% drift reduction No dependence on the diameter for the New thermocouple

17 Results of thermal cycling tests conducted in the CCPI Europe ISO accredited calibration laboratory. The test was conducted using 4 type K MI thermocouples. 2 of conventional design and 2 of the New Design. Then the test repeated using 4 type N MI thermocouple. 2 of conventional design and 2 of the New Design. All conductors from same batch for the respective thermocouple combinations The type K thermocouple were tested over 91 cycles and results taken at cycles 1, 16, 31, 46, 61, 76 and 91 The type N were tested over 90 cycles and results taken at cycles 1, 30, 60 and 90 The results are shown in the form of correction graphs indicating the changing measured output in Degrees Celsius.

18 Correction in Degrees C Correction in Degrees C Type K conventional results CCPI Europe Limited Type Type K K 3.0mm Single Type K 3.0mm Type wall Single K wall 3.0mm calibration cycle 1, 16 and cycle 31 wall calibration Single results wall results calibration cycle 1, 16, 31, 46 and cycle cycle results 1 and on cycle 16 cycle 1, 16, 31, 61 46, 61, 76 and cycle 91 Type K 3.0mm Type K Single 3.0mm wall Single calibration wall calibration results on results cycle on 1, cycle 16, 311 and cycle Test Temperature in Degrees C Test Temperature in in Degrees C /F2 3mm Single Wall cycle /B2 3mm Single Wall cycle /F2 3mm Single Wall cycle /B2 3mm Single Wall cycle /F2 3mm Single Wall cycle /B2 Test Temperature 3mm Single Wall in Degrees cycle 1C 13222/F2 3mm Single Wall cycle 16 Correction in Degrees Correction in in Degrees C C 13222/B /F2 3mm 3mm Single Single Wall Wall cycle 31 cycle /B2 3mm Single 13222/F2 Wall cycle 3mm 31Single Wall 13222/F2 cycle 3mm 31 Single Wall Cycle /B2 3mm 13222/B2 Single 3mm Wall Single cycle Wall Cycle /F /F2 3mm 3mm Single Single Wall Wall cycle cycle /B2 Test Temperature 3mm Single in Wall Degrees cycle 1C /F2 3mm Single Wall cycle /B2 IEC 13222/F mm 13222/F23mm Class Single 13222/B /F2 3mm Single 1 Wall tolerances Cycle /B2 3mm Single 3mm Single Wall Single Wall cycle Wall cycle /F2 Wall Cycle cycle /B2 3mm /F /B2 3mm Single 3mm 3mm Wall 13222/F2 Single Wall Cycle 3mm Wall cycle cycle Single Wall Cycle /B2 131 IEC 13222/F /B2 3mm 13222/B Single 3mm Class 3mm 1 Single Wall Single Tolerances Wall Cycle Wall Cycle cycle /F2 3mm Single Single Wall Wall Cycle Cycle /B2 3mm Single 13222/B2 Wall Cycle 3mm 91Single Wall IEC Cycle class 61 1 tolerances IEC 13222/B2 IEC Class 3mm Class Single 1 tolerances 1 tolerances Wall cycle 16 IEC 13222/F Class 3mm 1 Single Tolerances Wall Cycle /B2 3mm Single Wall Cycle 46

19 Correction Correction in Degrees Correction in Degrees in Degrees C C Type K New Dual Wall results CCPI Europe Limited Type K 3.2mm Double Type K wall 3.2mm calibration Double results wall calibration cycle 1, results 16, 31 on and cycle Type K Type 3.2mm K Double 3.2mm Double wall wall calibration wall calibration results on results on cycle on 1, 116 and and cycle 1, 16, cycle 46 31, 46, 61 and cycle 76 cycle cycle 1, 16, 1, 31, 16, 46, 31, 61, and 76 and cycle cycle Test Temperature in Degrees C Test Temperature in in Degrees C Test Temperature in Degrees C 13168/F /F2 3.2mm 3.2mm Double Double Wall cycle Wall 1 cycle /B2 3.2mm Double 13168/B2 Wall cycle 13.2mm Double Wall 13168/F2 cycle 13.2mm Double Wall cycle /F2 3.2mm 13168/B2 Double 3.2mm Wall Double cycle Wall 16 cycle /F /B2 3.2mm Double Wall Wall cycle cycle /B /F2 3.2mm Double Wall Wall cycle cycle /F /B2 3.2mm Double Wall cycle cycle /F2 3.2mm Double Wall cycle /B2 3.2mm Double Wall cycle /F2 3.2mm Double Wall Cycle /B2 3.2mm Double Wall Cycle /F2 3.2mm Double Double Wall Cycle Wall cycle 46 cycle /B2 3.2mm Double Double Wall Wall Wall Cycle cycle 46 cycle /F2 3.2mm Double Wall Wall Cycle cycle /B /F2 Double Wall cycle /F2 Wall cycle /B2 Wall cycle /B /B2 3.2mm 3.2mm Double 3.2mm Double Wall Cycle 13168/F2 Double Wall 61 Cycle Wall 3.2mm Wall /B2 3.2mm Double cycle cycle 16 Double 16 Wall cycle 13168/F /F2 Wall Cycle 3.2mm 61 1 Double Double Wall 13168/F2 3.2mm Double Wall Cycle /B2 3.2mm Double Wall Cycle 76 Wall Cycle 76 cycle cycle 13168/B2 3.2mm 13168/B2 Double 13168/B2 3.2mm Wall Double cycle Wall 1 Cycle cycle cycle IEC 13168/F Class 3.2mm 1 tolerances Double Wall Wall Cycle Cycle /B2 3.2mm Double Wall Wall Cycle Cycle /F2 IEC mm Class 1 Double tolerances Wall Cycle 61 IEC Class 13168/F2 1 tolerances 13168/F /B2 3.2mm Double Wall Wall 3.2mm Cycle Double 4661 Wall cycle 13168/B2 IEC mm Class Double 1 tolerances Wall Cycle 13168/B mm IEC Double Wall Class cycle 1 tolerances 16

20 Working within tolerances longer Type K 3.2mm Double wall and 3.0mm Single wall results at cycle 91 Correction in Degrees C Test Temperature in Degrees C 13222/F2 3mm Single Wall 13222/B2 3mm Single Wall 13168/F2 3.2mm Double Wall 13168/B2 3.2mm Double Wall Series5 ASTM E230 Special Tolerances (IEC Class 1)

21 Correction in in Degrees C C Type N conventional results CCPI Europe Limited Type Type N 3mm N 3mm Single Single wall wall calibration calibration results results on on cycle cycle 1, 130 and and cycle cycle Test Temperature in Degrees C Test Temperature in Degrees C 13047/F Single Wall 1st Cycle 13047/B Single Wall 1st Cycle 13047/F Single Wall 30th Cycle 13047/F 13047/B Single Single Wall Wall 1st 30th Cycle Cycle 13047/B 13047/F Single Wall 1st 60 cycles Cycle 13047/B 13047/F Single Wall 60 30th cycles Cycle 13047/B IEC Single 2013: Wall Class 30th 1 Cycle tolerances IEC : Class 1 tolerances

22 Correction in Degrees C Correction in in Degrees C Type N New Dual Wall results CCPI Europe Limited Type Type N 3.2mm N Double wall wall calibration results results on on cycle on cycle cycle 1, 30, 1 and 1, 6030 cycle and and 30cycle Test Temperature in Degrees C Test Temperature in Degrees C 13167/F Double Wall 1st Cycle 13167/B Double Wall 1st Cycle 13167/F Double Wall 30th Cycle 13167/B Double Wall 30th Cycle 13167/F Double Wall 60 cycles 13167/F Double 13167/F Wall Double 1st Cycle Wall 1st Cycle13167/B Double Wall 13167/B 1st CycleDouble Wall 13167/F 1st Cycle Double Wall 30th Cycle 13167/B Double Wall 60 cycles 13167/F 13167/B Double Double Wall 30th Wall Cycle 30th Cycle 13167/F 13167/F Double 13167/B Double Wall Double Wall 60 cycles Wall 9030th cycles Cycle 13167/B 13167/B Double Wall 60 IEC cycles Double Class Wall 1 IEC tolerances 90 cycles Class 1 tolerances IEC Class 1 tolerances

23 Correction in Degrees C CCPI Europe Limited Working within tolerances longer Type N 3.2 and 3.0mm Double and Single wall calibration results after 60 cycles Test Temperature in Degrees C 13047/F Single Wall 13047/B Single Wall 13167/F Double Wall 13167/B Double Wall IEC Class 1 tolerances

24 Latest CCPI tests on dual wall MI cable

25 Latest test data on dual wall MI cable Initial tests on the dual wall MI cables have mainly been focused on the sizes recommended for higher temperatures. -- 3mm to 6mm diameter In practise MI cable of different diameters are used in industry and often the smaller sizes are used in the high temperature region above 1100 C So to conduct this latest set of tests we manufactured a range of different MI cable diameter's in the dual wall configuration. - Type K 1.5mm - Type N 2mm and 1.5mm

26 Latest test data on dual wall MI cable These latest set of tests were designed to see the short term performance of the varying smaller diameters and thermocouple types under cyclic, high temperature and mid temperature conditions. All tests were conducted in the CCPI Europe ISO accredited calibration laboratory. The tests conducted were comparative tests in which the test dual wall thermocouples were matched or compared with conventional design MI cables which had been manufactured from the same original batch materials for both the thermocouple conductors and outer sheathing. The results are shown in the form of difference graphs indicating the change in output in Degrees Celsius.

27 Latest test data on dual wall MI cable The next set of result we are going to be looking at are high temperature range (650 to 1250 C) for :- Type K 1.5mm and type N 2mm and 1.5mm diameter constructions For this test we measured the output of : mm diameter Inconel sheathed conventional type K MI construction against 1.5mm Inconel sheathed type K dual wall constructions & -- 2mm diameter Inconel sheathed conventional type N MI construction against 2mm Inconel sheathed type N dual wall constructions. & mm diameter Inconel sheathed conventional type N MI construction against 1.5mm Inconel sheathed type N dual wall constructions The test thermocouples were tested over 20 cycles and the following results show the measured difference in Degrees Celsius between the 1 st and 20 th cycles. Immersion depth for test thermocouples was 500mm

28 Latest test data on dual wall MI cable

29 Temperature in Degrees Celsius Type K 1.5mm Conventional v 1.5mm Dual Wall results difference between 1st and 20th cycles Test Temperature in Degrees Celsius 14559/2 1.5mm Con difference between 1st & 20th cycles 14544/B 1.5mm DW difference between 1st & 20th cycles

30 Type N 2mm Conventional v 2mm Dual Wall results difference between 1st and 20th cycles Difference in Degrees Celsius Test temperature in Degrees Celsius 14484/A 2mm Con difference between 1st & 20th cycle 14541/A 2mm DW difference between 1st & 20th cycle

31 Type N 1.5mm Conventional v 1.5mm Dual Wall results difference between 1st and 20th cycles Difference in Degrees Celsius Test temperature in Degrees Celsius 14492/A 1.5mm Con difference between 1st & 20th cycle mm DW difference between 1st & 20th cycle

32 Latest test data on dual wall MI cable The next set of result we are going to be looking at are mid temperature range (400 to 1000 C) for :- Type K and type N 1.5mm diameter only with short immersion (200mm) For this test we measured the output of : mm diameter Inconel sheathed conventional type N MI construction against 1.5mm Inconel sheathed type N dual wall constructions. & mm diameter Inconel sheathed conventional type K MI construction against 1.5mm Inconel sheathed type K dual wall constructions The type N and K thermocouple were tested this time over 30 thermal cycles and the following results show the measured differences in Degrees Celsius between the 1 st and 30 th cycles of the test.

33 Latest test data on dual wall MI cable Mid range Thermal Cycle Temperature in Degrees Celsius Time in minutes Cycle raise and fall

34 mm type K Dual Wall v 1.5mm type K Conventional (Short Immersion furnace), difference between 1st and 30th cycle Difference in Degrees Celsius Test temperature in Degrees Celsius 14545/1 DW K 1.5mm difference between 1st & 30th cycles 14559/1 Con K 1.5mm difference between 1st & 30th cycles 1st Cycle

35 Differences in C Type N 1.5mm Conventional v 1.5mm Dual Wall results difference between 1st and 30th Test temperatures in C /B DW 1.5mm N difference between 1st & 30th cycles 14492/B Con 1.5mm N difference between 1st & 30th cycles

36 Other tests (EMPRESS) CCPI Europe Limited Currently under a European funded program (EMPRESS) aimed at enhancing process efficiency through improved temperature measurement. A number of addition tests on this dual wall MI thermocouple cable are being conducted. The bulk of the laboratory test under the EMPRESS project on the dual wall MI cable will be conducted under the direction of the University of Cambridge. In addition a number of field trial will be conducted, these are currently underway, at industrial sites. Two in particular are being conducted at Bodycote heat treatment sites in the UK and Europe. These will involve dual wall MI thermocouples being used as the operational measurement sensors at high temperature under real life operational industrial conditions. The results are expected by late 2017.

37 Different cable geometry 3mm Dual wall thick wall The test data we have been looking at so far has been all from the larger wall dual wall configuration. The dual wall configuration is a much more flexible design compared to single wall conventional thermocouples: by changing the inner wall to outer wall thickness ratio it is possible to tweak or control the drift performance of the double wall thermocouples and their mechanical properties. As a result dual wall thermocouples with a wide variety of performance can be designed to suit different and varying applications. CCPI is currently working on different inner wall thicknesses as part of the development and optimisation of the dual wall thermocouples. In particular, a reduced wall or thin wall geometry is currently under test. 3mm Single wall (conventional) 3mm Dual wall thin wall

38 Test results for dual wall thin wall coming soon!

39 The Next Step Finally all the results from testing conducted on the dual wall MI cable has currently only been done under standard atmosphere conditions. During the first half of 2017 addition testing will be conducted under inert and vacuum conditions replicating many customers actual operational environments.

40 Questions