Isotech 96178 Operating instructions

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HTSPRT Model 96178 Iss.06 –03/11
HIGH TEMPERATURE
STANDARD PLATINIUM
RESISTANCE THERMOMETER
MODEL 96178
User Maintenance Manual/Handbook
Isothermal Technology Limited, Pine Grove, Southport, PR9 9AG, England
Tel: [phone] Fax: [phone] Internet: www.isotech.co.uk E-mail: [email protected]
The company is always willing to give technical advice and assistance where appropriate. Equally, because of the programme of continual
development and improvement we reserve the right to amend or alter characteristics and design without prior notice. This publication is for
information only

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HTSPRT Model 96178 Iss.06 –03/11
CONTENTS
CONTENTS ....................................................................................................................................................................................... 2
GUARANTEE...................................................................................................................................................................................... 3
OPERATING INSTRUCTIONS .......................................................................................................................................................... 4
INTRODUCTION .......................................................................................................................................................................... 4
RETURNING YOUR THERMOMETER TO ISOTECH.................................................................................................................. 4
Preparing the box......................................................................................................................................................................... 5
STABILITY EVALUATION ................................................................................................................................................................. 6
INTRODUCTION .......................................................................................................................................................................... 6
METHOD ....................................................................................................................................................................................... 6
RESULTS......................................................................................................................................................................................... 7
DISCUSSION OF RESULTS ........................................................................................................................................................... 7
CONCLUSION............................................................................................................................................................................... 8
FURTHER WORK........................................................................................................................................................................... 8
GLOSSARY OF METROLOGICAL TERMS ...................................................................................................................................... 11
ACCURACY OF MEASUREMENT............................................................................................................................................... 11
REPRODUCIBILITY OF MEASUREMENTS ................................................................................................................................. 11
UNCERTAINTY OF MEASUREMENT ........................................................................................................................................ 11
STABILITY..................................................................................................................................................................................... 11
DRIFT............................................................................................................................................................................................ 11
PACKING INSTRUCTIONS FOR THE RETURN OF YOUR 96178 ............................................................................................... 12

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HTSPRT Model 96178 Iss.06 –03/11
GUARANTEE
This instrument has been manufactured to exacting standards and is guaranteed for twelve months against electrical
break-down or mechanical failure caused through defective material or workmanship, provided the failure is not the
result of misuse. In the event of failure covered by this guarantee, the instrument must be returned, carriage paid, to
the supplier for examination and will be replaced or repaired at our option.
FRAGILE CERAMIC AND/OR GLASS PARTS ARE NOT COVERED BY THIS GUARANTEE
INTERFERENCE WITH OR FAILURE TO PROPERLY MAINTAIN THIS INSTRUMENT MAY INVALIDATE THIS
GUARANTEE
RECOMMENDATION
The life of your ISOTECH Instrument will be prolonged if regular maintenance and cleaning to remove general dust
and debris is carried out.
ISOTHERMAL TECHNOLOGY LTD.
PINE GROVE, SOUTHPORT
PR9 9AG, ENGLAND
TEL: [phone]/544611
FAX: [phone]
The company is always willing to give technical advice and assistance where appropriate. Equally, because of the
programme of continual development and improvement we reserve the right to amend or alter characteristics and
design without prior notice. This publication is for information only.

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HTSPRT Model 96178 Iss.06 –03/11
OPERATING INSTRUCTIONS
INTRODUCTION
You or your company has just paid a considerable sum of money to purchase this 96178.
Although the materials to make the 96178 are very costly, it has also taken up to 1000 hours to prepare the 96178 for
your use.
It is not a product that can be assembled, tested and sold; it is produced, calibrated, aged and re-calibrated, until its
characteristics are stable enough to meet the exacting needs of ITS 90.
The weeks of work that go into its production make each 96178 more than another product. Each 96178 already has
a character and a history before it leaves us. Please look after it. Regard yourself as its custodian rather than its
owner.
1. Always keep the 96178 in its case when not in use.
2. When in use, support the handle.
3. Cool and store the 96178 in the same place as you normally use it.
4. Each time before you use the 96178 clean off all traces of grease by using a chlorinated solvent.
5. Even go so far as using gloves to handle the 96178, and keep the gloves clean.
6. Quartz is glass. It is a supercooled liquid. At 800 C and above, your 96178 will bend and bow if you do not
support it along its complete length. At high temperatures I recommend that the 96178 be housed inside a
close fitting recrystallised Alumina closed ended tube, which has been pre-fired to 1000 C, or better still a
silicon carbide tube.
7. Quartz is transparent in two senses of the word. At temperatures above 700 C metallic vapours can pass
through the quartz and attack the pure platinum sensing element. Isotech have developed a product which
can be attached to the 96178 to prevent this happening to a 960 Ioniser. A Model 960 Ioniser is provided
free with each 96178.
8. If you have purchased the „Open‟ version of the 96178, open the valve at high temperatures and close it
before bringing the 96178 down to room temperature. This will ensure that no moisture builds up inside the
thermometer.
RETURNING YOUR THERMOMETER TO ISOTECH
Due to the fragility of the 96178 we strongly recommend that this is not transported unless personally hand carried.
In the event that the unit must be shipped by courier then the following instructions must be adhered to and
reference to diagram on page 12.

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HTSPRT Model 96178 Iss.06 –03/11
Preparing the box
Place the two foam blocks over the closed case and lower into inner box. Pad out ends with polystyrene chips to
stop the unit from moving - seal the box, lower it into the outer box and fill with chips, then lift the inner box slightly
so the polystyrene chips completely surround it. Place the protective sheath if supplied on top of the chips and seal
the box.
Always remember to label the box thoroughly with “fragile” and “this way up” labels and arrange adequate insurance
cover.
Your unit should now be ready to send.

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HTSPRT Model 96178 Iss.06 –03/11
STABILITY EVALUATION
INTRODUCTION
The 96178 is one of a new generation of thermometers designed at Isotech. It is a high temperature thermometer
working up to 1000 C and being 0.25 ohms at 0 C.
Its main radical and new features are:
1. The 96178 can be supplied pre-sealed with an inert gas containing 10% oxygen or with a valve built into the
handle so the user can allow the thermometer to breath.
2. The quartz used is a new and more pure material.
3. The internal construction is made of many small parts to eliminate stem conduction.
4. The internal structure contains a platinum light scattering disc to reflect radiant energy.
In this report the first production unit was cycled to the silver point to test the reproducibility of the W value at silver,
and to check the stability of RTPW.
METHOD
The 96178 thermometer, like all high temperature thermometers will change its characteristics if subjected to step
changes of temperature. The way in which the thermometer is temperature cycled is therefore very important.
In this series of tests the following strategy was adopted:-
The thermometer was placed in a pre-warming/annealing furnace at 400 C. The furnace temperature was then
slowly raised to 850 C (The apparatus used was the Isotech Dual Furnace which has been pre-programmed with
ramp-rates suitable for pre-warming the High Temperature Thermometers). From this furnace, the thermometer
was transferred to a heat pipe furnace in which was placed a silver cell. The silver had previously been melted and
partially frozen.
After 30 minutes in the cell, during which time and after stabilisation 4 to 6 readings were recorded, the thermometer
was transferred back to the annealing furnace, still at 850 C.
The annealing furnace was then cooled to 425 C overnight and RTPW measured the next morning.
Other thermometers of proven good stability were cycled with the 96178 to add further confidence that the method
gave stable results.

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HTSPRT Model 96178 Iss.06 –03/11
RESULTS
The following results were obtained during two temperature cycles to the silver point. Mean values are tabulated.
Serial No. 96178/1 is the new thermometer.
Serial No. 962/148 the best thermometer from my store of standards - it also "breathes" i.e. the air inside the stem is
not sealed in.
Ohms or ratio
962/148
96178/1
Initial RTPW
0.2362608
0.2100675
R Ag
1.0127804
0.9004547
R TPW
0.2362600
0.2100668
W Ag
4.2867197
4.2865160
W Ga
1.1181537
1.1181429
R Ag (2)
1.0127804
0.9004532
R TPW (2)
0.2362602
0.2100667
W Ag (2)
4.2867160
4.2865109
W Ga (2)
1.1181541
1.1181439
DISCUSSION OF RESULTS
High temperature thermometers take a long while - many hundred, if not thousands of hours - to stabilise completely.
Thermometer 962/148 is some 3 to 4 years old and has proved to be our most stable thermometer.
96178/1 was stabilised only overnight after its arrival from manufacture; even so the stability of the new thermometer
is remarkable.
There is always an initial shift in the characteristics of a high temperature thermometer during its first cycle to the
silver point. In this instance, both thermometers became more fully annealed, and so the RTPW was reduced by 0.7 &
0.8 mK; then, between the first and second calibrations the RTPW remained stable at 0.1 and 0.2 mK.
Some high temperature thermometers exhibit better stability in the reproducibility of the resistance at the silver
point, whilst others keep better W silver stability. In this evaluation we can look at both R silver and W silver.
The R silver reproducibility of Serial No. 962/148 was perfect -a very unusual - if not unique - situation.
96178/1 thermometer reproduced R silver by 1.5 mK, still exceptionally good.
962/148 reproduced W silver to within the equivalent of about 1 mK
96178/1 to within the equivalent of about 1.5 mK.
These are both exceptionally good results.
To put the above results into context; N.P.L. would permit a shift of up to 5 mK in RTPW and a spread of 20 mK in W
silver during a full calibration cycle.

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HTSPRT Model 96178 Iss.06 –03/11
CONCLUSION
The 96178/1 thermometer has shown itself to be as stable as our very best standard thermometer after only an
overnight anneal.
FURTHER WORK
As more thermometers are produced and tested further reports will be issued to confirm the results above.
Uncertainties vary depending on the temperature range of calibration.
Isotech‟s Models 670H and 96178 Standard Platinum Resistance Thermometers (SPRT‟s) can be calibrated using
procedural techniques aimed at achieving the uncertainties outlined in Issue 13 of our Schedule of Accreditation see
page 11.
Alternatively, at an extra cost the SPRT‟s can be calibrated in line with a specific procedure aimed at achieving the
uncertainties outlined in Issue 35 of our Schedule of Accreditation, see page 10.

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HTSPRT Model 96178 Iss.06 –03/11

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HTSPRT Model 96178 Iss.06 –03/11

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HTSPRT Model 96178 Iss.06 –03/11
GLOSSARY OF METROLOGICAL TERMS
ACCURACY OF MEASUREMENT
The closeness of the agreement between the result of a measurement and the (conventional) true value of the
measurand*
REPRODUCIBILITY OF MEASUREMENTS
The closeness of the agreement between the results of measurements of the same measurand, where the individual
measurements are carried out changing conditions such as:
method of measurement
oberserver
measuring instrument
location
conditions of use
time
NOTES:
1. A valid statement of reproducibility requires specification of the conditions changed.
2. Reproducibility may be expressed quantitatively in terms of the dispersion of the results.
UNCERTAINTY OF MEASUREMENT
An estimate characterising the range of values within which the true value of a measurand lies.
Note: Uncertainty of measurement comprises, in general, many components. Some of these components may be estimated
on the basis of the statistical distribution of the results of series of measurements and can be characterised by experimental
standard deviations. Estimates of other components can only be based on experience or other information.
STABILITY
The ability of a measuring instrument to maintain constant its metrological characteristics.
DRIFT
The slow variation with time of metrological characteristic of a measuring instrument.
*Measurand = a quantity subjected to measurement

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HTSPRT Model 96178 Iss.06 –03/11
PACKING INSTRUCTIONS FOR THE RETURN OF YOUR 96178