Isotech M17705 Operating instructions

Page 1 of 40
Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
DUAL FURNACE
FOR MODELS
M17705, M17706 & M17707
User Maintenance Manual/Handbook
Isothermal Technology Limited, Pine Grove, Southport, PR9 9AG, England
Tel: [phone] Fax: [phone] Internet: www.isotech.co.uk E-mail: [e-mail]
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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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
CONTENTS
GUARANTEE................................................................................................................................................................ 3
EMC INFORMATION.......................................................................................................................................... 4
ELECTRICAL SAFETY.......................................................................................................................................... 4
HEALTH AND SAFETY INSTRUCTIONS ................................................................................................................... 5
DUAL FURNACE CERTIFICATE OF TEST ................................................................................................................. 6
UNPACKING................................................................................................................................................................ 7
SAFETY ......................................................................................................................................................................... 8
CAUTIONARY NOTE.............................................................................................................................................. 8
THIS EQUIPMENT MUST BE EARTHED ................................................................................................................ 8
FUSE AND NEUTRAL LINK REPLACEMENT ........................................................................................................ 8
INTRODUCTION ........................................................................................................................................................ 9
THE 3 DUAL FURNACES .......................................................................................................................................... 10
MODEL 17707........................................................................................................................................................ 10
MODEL 17706........................................................................................................................................................ 10
MODEL 17705........................................................................................................................................................ 10
OPERATIONAL CONVENIENCE ............................................................................................................................. 11
ACKNOWLEDGEMENT............................................................................................................................................ 12
COMMISSIONING ..................................................................................................................................................... 13
MODEL 17707 WATER HEAT-PIPE FURNACE........................................................................................................ 14
FINAL PART OF THE COMMISSIONING INSTRUCTIONS ................................................................................ 14
NEXT GENERATION CALIBRATION APPARATUS FOR INDIUM AND TIN FIXED POINTS ............................. 15
INTRODUCTION .................................................................................................................................................. 15
DESCRIPTION........................................................................................................................................................ 15
METHOD OF OPERATION................................................................................................................................... 15
SPECIFICATION ........................................................................................................................................................ 16
HOW TO ORDER .................................................................................................................................................. 16
THE POTASSIUM HEAT-PIPE FURNACE, MODEL 17706 ...................................................................................... 17
FINAL PART OF THE COMMISSIONING INSTRUCTIONS ................................................................................ 17
NEXT GENERATION CALIBRATION APPARATUS FOR ZINC, ALUMINIUM AND SILVER FIXED POINTS ..... 18
INTRODUCTION .................................................................................................................................................. 18
DESCRIPTION........................................................................................................................................................ 18
METHOD OF OPERATION................................................................................................................................... 18
SPECIFICATION ........................................................................................................................................................ 19
THE SODIUM HEAT-PIPE FURNACE, MODEL 17705 ............................................................................................ 20
FINAL PART OF THE COMMISSIONING INSTRUCTIONS ................................................................................ 20
NEXT GENERATION CALIBRATION APPARATUS FOR ALUMINIUM, SILVER AND COPPER FIXED POINTS 21
INTRODUCTION .................................................................................................................................................. 21
DESCRIPTION........................................................................................................................................................ 21
METHOD OF OPERATION................................................................................................................................... 21
SPECIFICATION ........................................................................................................................................................ 22
ELIMINATING CONTAMINATION DURING THE CALIBRATION OF HIGH TEMPERATURE THERMOMETERS23
ANNEALING COMPONENT OF THE DUAL FURNACE SHOWING AIR FLOW.............................................. 23
MAINTENANCE ........................................................................................................................................................ 25
SPARE PARTS ............................................................................................................................................................. 26
CELL HANDLING ...................................................................................................................................................... 27
CELL KIT................................................................................................................................................................. 27
THERMOMETRIC FIXED POINTS; A TUTORIAL.................................................................................................... 31
DEFINING FIXED POINTS AND RELATED DATA ................................................................................................. 33
GENERAL NOTE ON ISOTECH METAL FREEZE POINT CELLS ........................................................................... 34
PRECAUTIONS TO PREVENT DEVITRIFICATION OF QUARTZ ENVELOPES .................................................... 35
GENERAL COMMENT .............................................................................................................................................. 36
ADDITIONAL SERVICES AND INFORMATION ...................................................................................................... 37
FIGURE 1; SECTION THROUGH DUAL FURNACE............................................................................................ 38
FIGURE 2; SEALED METAL FREEZING POINT CELL.......................................................................................... 39
FIGURE 3; SEALED METAL FREEZING POINT CELL BODY DIMENSIONS ...................................................... 40

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
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.
We recommend that this instrument to be re-calibrated annually.
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.

Page 4 of 40
Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
EMC INFORMATION
This product meets the requirements of the European Directive on Electromagnetic Compatibility (EMC)
89/336/EEC as amended by EC Directive 92/31/EEC and the European Low Voltage Directive 73/25/EEC, amended
by 93/68/EEC. To ensure emission compliance please ensure that any serial communications connecting leads are
fully screened.
The product meets the susceptibility requirements of EN 50082-1, criterion B.
Symbol Identification
Publication
Description
ISO3864
Caution (refer to manual)
IEC 417
Caution, Hot Surface
ELECTRICAL SAFETY
This equipment must be correctly earthed.
This equipment is a Class 1 Appliance. A protective earth is used to ensure the conductive parts cannot become live
in the event of a failure of the insulation.
The protective conductor of the flexible mains cable which is coloured green/yellow MUST be connected to a
suitable earth.
The Blue conductor should be connected to Neutral and the Brown conductor to Live (Line).
Warning: Internal mains voltage hazard. Do not remove the panels.
There are no user serviceable parts inside. Contact your nearest Isotech agent for repair.
Voltage transients on the supply must not exceed 2.5kV.
Conductive pollution, e.g. Carbon dust, must be excluded from the apparatus. EN61010 pollution degree 2.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
HEALTH AND SAFETY INSTRUCTIONS
1. Read this entire manual before use.
2. Wear appropriate protective clothing.
3. Operators of this equipment should be adequately trained in the handling of hot and cold items and liquids.
4. Do not use the apparatus for jobs other than those for which it was designed, i.e. the calibration of
thermometers.
5. Do not handle the apparatus when it is hot (or cold), unless wearing the appropriate protective clothing and
having the necessary training.
6. Do not drill, modify or otherwise change the shape of the apparatus.
7. Do not dismantle the apparatus.
8. Do not use the apparatus outside its recommended temperature range.
9. If cased, do not return the apparatus to its carrying case until the unit has cooled.
10. There are no user serviceable parts inside. Contact your nearest Isotech agent for repair.
11. Ensure materials, especially flammable materials are kept away from hot parts of the apparatus, to prevent
fire risk.
12. Ensure adequate ventilation when using oils at high temperatures.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
DUAL FURNACE CERTIFICATE OF TEST
Serial No:
Prior to despatch the following tests were carried out.
Insulation Test MΩDate
Earth Impedance ΩDate
Temperature cycle to maximum temperature Date
Communications test (if applicable) Date
Laboratory test at °C
Comments or concessions
Controller parameters are listed in an appendix of the manual
The above Serial No. Furnace was tested as above and found to comply with the specifications.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
UNPACKING
EVERY EFFORT HAS BEEN MADE TO PACKAGE THIS UNIT FOR TRANSPORT AND TO ENSURE ITS GOOD
CONDITION ON ARRIVAL AT ITS DESTINATION.
BEFORE COMMISSIONING IT IS NECESSARY TO REMOVE THE FURNACE CORE TRANSIT CLAMP. TO AVOID
DAMAGE PLEASE FOLLOW INSTRUCTIONS:
1. Slacken the central nut using the required tube spanner; the insertion of a screwdriver through the tube
spanner will prevent the central stud turning.
2. Remove the 3 screws securing the transit clamp to the top of the unit. Slacken each screw by degrees
equally.
3. Gently lift the transit clamp vertically; the attached tube and rubber securing block will thereby be extracted
from the furnace core.
4. Normal commissioning procedure may now be followed.
5. Keep the transit clamp and use it if the furnace is ever transported.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
SAFETY
CAUTIONARY NOTE
Products of Isothermal Technology Ltd are intended for technically trained and competent personnel familiar with
good laboratory practice. It is expected that personnel using this equipment will be knowledgeable and skilful in the
management of apparatus which may be under power or under extremes of temperature (molten metals, cryogenic
liquids, etc.) and will appreciate the hazards which may be associated with, and the precautions to be taken with,
such equipment.
THIS EQUIPMENT MUST BE EARTHED
The furnace is supplied with a fuse carrier fitted with a neutral link. This is clearly labelled and is for use with a mains
system with a neutral line, such as the UK supply. If the furnace is to be used on a system where both supply lines
are live with respect to earth then the neutral fuse link should be replaced with a fuse. A spare fuse is supplied with
the furnace.
FUSE AND NEUTRAL LINK REPLACEMENT
Hazardous voltages are exposed when the rear furnace panel is removed. Before removing the panel you must
isolate the furnace from the electrical supply. To replace the main electrical fuse or to replace the neutral link bar it
is necessary to remove the rear panel; see warning above. The panel will become free after the four corner screws
are removed.
The fuse holders will be seen at the lower right hand side of the cabinet. The black fuse holder will always contain a
fuse. The white fuse holder will leave Isotech with a neutral shorting bar. As explained elsewhere, if your local supply
does not have a neutral line but has both lines live with respect to earth this link should be replaced with a fuse and
the holder labelled to this effect.
The top half of the fuse carrier pulls free from the lower body.
Two spare fuses are supplied with the furnace; they are type A2 and have a rating of 10A for the low and medium
temperature furnace and 32A for the high temperature furnace.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
INTRODUCTION
The Dual Furnace range of calibration apparatus comprises 3 models, all working on the same principle and having
the following features in common:
1. A rack for storage, at around room temperature, of up to 4 thermometers. Lined with ceramic board, the
rack will not be damaged if very hot thermometers are placed in it.
2. A furnace of diameter 50mm and depth 400mm which can be used to pre-warm or anneal up to 4
thermometers.
3. A pre-calibration pocket to install a single thermometer immediately prior to calibration or to house the
monitor thermometer between periods of use.
4. A heat-pipe furnace to create optimal conditions for an appropriate range of fixed point cells. The use of
freeze-point cells within the heat pipe is described in the manual which accompanies Isotech cells.
All 4 features are built into one cabinet, making the dual furnace a self-contained calibration facility.
Both component furnaces of the dual furnace can be fitted with communications interfaces for automated use.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
THE 3 DUAL FURNACES
MODEL 17707
Contains a water heat pipe, giving an operational temperature range from 125°C to 250°C and thus making it an ideal
system for realisation of Indium and Tin freeze points.
Its annealing furnace has a temperature range from near ambient up to 700°C.
MODEL 17706
Contains a potassium heat pipe with a temperature range from 400°C to 1000°C, thus encompassing Zinc,
Aluminium and Silver freeze points.
Its annealing furnace has a temperature range from near ambient to 950°C.
MODEL 17705
Contains a sodium heat pipe with a temperature range from 450°C to 1100°C, thus constituting a facility for
Aluminium, Silver, Gold and Copper freeze point measurements.
Its annealing furnace has a temperature range from near ambient to 950°C.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
OPERATIONAL CONVENIENCE
Until the advent of the dual furnace, the handling of thermometers was treated as a separate problem, or ignored.
With the dual furnace, thermometers can be stored, pre-warmed, calibrated and annealed in one comprehensive
facility, without introducing contamination or strain.
The two furnaces in each dual furnace have independent temperature controllers and independent adjustable over-
temperature cut-outs for added security. These features are shown in the wiring diagram.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
ACKNOWLEDGEMENT
The Isotech dual furnace owes its origin to Dr. P. Marcarino of Italy. His research and development solved many of
the problems of contamination and handling of high temperature thermometers.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
COMMISSIONING
Connect the step down transformer to a suitable 230Vac supply.
Before connecting the unit to the mains power supply, check the impedance between live and earth, and neutral and
earth (values as low as 2MΩon arrival are acceptable since moisture may be present after transportation).
Familiarise yourself with controller operation; manuals are supplied with all equipment.
Plug in and switch on the dual furnace (figure 1) and operate the reset button. This will energise the annealing
furnace controller. Adjust the set point to 100°C (450 and 500°C for potassium 17706 and Sodium 17705 models)
and the over-temperature controller set point to 50°C above the controller set point. After 1 or 2 hours the
annealing furnace will stabilise. Adjust its over-temperature set point downwards until the circuit relay trips,
switching off the annealing furnace.
Later models of the furnace use a Eurotherm over-temperature cut-off controller. On these models the RESET
button is located below the over-temperature controller. The SP value should be set approximately 50°C higher
than the operating controller setting. If this limit should be exceeded the red push button switch will reset the
apparatus once the furnace temperature has fallen below the AL1 value.
To turn on system power at start up (or as required), it is necessary to depress the red push button.
To adjust SP press the "Scroll" until the controller indicates “SP”.
Press the UP or DOWN keys to modify the SP value.
NOTE; the annealing/pre-heating furnace controller has been pre-set to produce a slow change in temperature, in
line with the heating and cooling rates recommended for annealing of thermometers. Do not over-ride the control
settings.
The recrystallised alumina liner has a closed end and thermometers may be placed directly into the liner for
annealing.
Switch on the main furnace (heat pipe) and press the reset button. This will energise the heater.
The rate of change of temperature for a heat-pipe at low temperature must be controlled, and for this reason the
heat-pipe controller has been pre-programmed to warm up slowly to its minimum working temperature. The
parameters used to effect this control are not directly accessible, for safety reasons.
As soon as the minimum temperature has been reached, the initial restriction on the rate of approach to set point is
removed.
The remainder of the instructions differ for the three models; reference should be made to the page clearly marked
with the appropriate dual furnace model.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
MODEL 17707 WATER HEAT-PIPE FURNACE
FINAL PART OF THE COMMISSIONING INSTRUCTIONS
The heat up rate of the furnace is limited to ensure long life of the heat pipe.
Impose a heat pipe set point of 150°C and set the over-temperature controller to 200°C.
Allow 1 to 2 hours for the furnace to stabilise and then reduce the over-temperature cut-out setting until the relay
trips, thus switching off the furnace.
The 17707 furnace is now ready for use.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
NEXT GENERATION CALIBRATION APPARATUS FOR INDIUM AND TIN
FIXED POINTS
INTRODUCTION
Before calibrating a standard platinum resistance thermometer, it is usual to check its water triple point resistance
value and then to anneal the thermometer. The annealing temperature varies typically between 400 and 700°C.
DESCRIPTION
The new calibration apparatus developed by Isotech not only allows you to create and maintain the ITS 90 freezing
points of Indium and Tin using a water heat-pipe, but also provides a second furnace for annealing thermometers at
temperatures up to 700°C.
Complementary features of the apparatus are a pre-heating tube, maintained at the cell temperature, and a rack for
storage of up to 4 thermometers at approximately ambient temperature.
METHOD OF OPERATION
1. By adjusting the set-point to a few degrees above the appropriate melting point, the cell, (tin or indium) is
melted in the essentially temperature-gradient-free water-filled heat-pipe. When the cell's contents are
completely melted, the heat-pipe temperature is re-adjusted to a level 0.5°C below the freeze temperature
of the cell. When this set-point has been reached, a cold rod is introduced into the re-entrant tube of the cell
to initiate the freeze, giving a plateau that can be maintained for between 12 and 24 hours. A modified
technique is appropriate for tin, in the form of an applied thermal shock to the whole cell to counteract the
tendency for a slow, large undercool to occur.
2. The thermometers are removed from their rack and, assuming they have already been annealed and are
stable, are placed successively in the pre-warming tube for 5 minutes and then transferred to the cell for
calibration. After 20 to 30 minutes the thermometer can be removed slowly from the cell and, after cooling
to room temperature, the RTPW-value can be checked.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
SPECIFICATION
Dimensions of the cabinet containing the apparatus are:
Width: 600mm
Depth: 560mm
Height: 960mm (excluding thermometer storage rack)
Control: The heat-pipe and the annealing furnace are controlled independently to a resolution of
0.1°C.
Communications: RS422
Temperature range: 120°C to 250°C.
Over-temperature Provided on each furnace and operated by an independent sensor.
protection:
Supply: 2kW, 220-240V, 50/60Hz.
(110-120V to special order)
Performance: Essentially temperature-gradient-free heat-pipes provide the ideal apparatus for fixed point
calibration and give a virtually perfect freezing profile within the fixed point cell.
The addition of the second furnace enables thermometers to be stabilised before calibration,
by annealing out strain and removing any 3D oxides.
A comprehensive manual accompanies each apparatus.
Reproducibility of the temperatures of freezing indium or tin is typically ±0.1mK with Isotech fixed point cells.
HOW TO ORDER
Ask for Model 17707. We need to know your voltage and whether you require communications. A temperature
equalising block is an available option (for comparison calibration purposes).
PLEASE NOTE: You may wish to purchase cells and thermometers with this apparatus. Both are available from
Isotech. Next Generation Apparatus is also available for Zinc, Aluminium Silver and Copper fixed points. Please ask
for data sheets 17705 and 17706.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
THE POTASSIUM HEAT-PIPE FURNACE, MODEL 17706
FINAL PART OF THE COMMISSIONING INSTRUCTIONS
The initial slow temperature ramp is maintained until the temperature reaches 400°C.
Impose a heat-pipe set-point of 420°C and set the over-temperature controller to 450°C. Allow 1 to 2 hours for the
furnace to stabilise and then reduce the over-temperature cut-out setting until the relay trips, thus switching off the
furnace.
Allow the furnace to cool and isolate it from the electricity supply.
At the rear are two water connections; these should be connected to a controllable supply and a flow of 1 to 2 litres
of water per minute established - this prevents the top of the cabinet being over-heated at high furnace
temperatures. Run the water for 1 hour to check the furnace for absence of leaks (the floor underneath the cabinet
should be inspected).
The 17706 furnace is now ready for use.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
NEXT GENERATION CALIBRATION APPARATUS FOR ZINC, ALUMINIUM
AND SILVER FIXED POINTS
INTRODUCTION
Using high temperature thermometers presents many problems due to strain and contamination, which can very
easily be introduced into the thermometer during thermal cycling.
Limited understanding of the relevant mechanisms has resulted in a dearth of published information and of available
apparatus for the safe treatment of these sophisticated devices.
DESCRIPTION
Sufficient information now exists at Isotech to allow introduction of a new apparatus, specifically designed not only to
realise and maintain the ITS 90 fixed points of Zinc, Aluminium and Silver, but also to pre- and post-condition the
thermometers to be calibrated. To this end a second furnace has been incorporated, which, because of its design,
will permit conditioning to be carried out safely and without introducing contaminants into thermometers.
Complementary features of the apparatus are a pre-calibration tube (held at the temperature of the fixed point)
made of a unique and gas tight material, together with a rack for storage of up to 4 thermometers at approximately
ambient temperature.
METHOD OF OPERATION
1. By adjusting set-point to a few degrees above the appropriate melting point, the cell (zinc, aluminium or
silver) is melted in an essentially temperature gradient free potassium-filled heat-pipe. When melting is
complete, the heat-pipe temperature is readjusted to a level 0.5°C below the freeze temperature of the cell.
When this set-point has been reached a cold rod is introduced into the re-entrant tube of the cell to initiate
the freeze, giving a plateau that can be maintained for between 12 and 24 hours.
2. The thermometers are removed from their storage rack and placed in the pre-conditioning furnace. The
furnace is slowly heated to 400°C (if the cell is Zinc), 650°C (for Aluminium) or 900°C (for Silver).
During conditioning, thermometers are protected from contamination by a slow air flux around them.
CAUTION: it is essential, when thermometers are inserted into furnaces, to keep their heads cool. This can
be accomplished by blowing air, at ambient temperature, across them by means of a free-standing fan.
3. Thermometers are transferred individually to the cell for 20 to 30 minutes, for calibration, and then returned
to the post-conditioning furnace.
4. When all the thermometers have been calibrated, the post-annealing furnace is slowly cooled to 450°C after
which they can safely be exposed to room temperature and, thereafter, measured at the triple point of
water.
Throughout the time the thermometers are above 450°C the temperature changes are slow enough to
prevent strain, and the slow flow of air prevents contamination at high temperatures.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
SPECIFICATION
Dimensions of the cabinet containing the apparatus are:
Width: 600mm
Depth: 560mm
Height: 960mm (excluding thermometer storage rack)
Control: The heat-pipe and the thermometer furnace are controlled independently to a resolution of
0.1°C.
Communications: RS422
Over-temperature Provided on each furnace and operated by an independent sensor.
Protection:
Temperature range: 400 to 1000°C.
Power: 3kW, 110V, 50/60Hz
Performance: Essentially temperature gradient-free heat-pipes provide the ideal apparatus for fixed point
calibration and give a virtually perfect freezing profile within the fixed point cell.
The addition of the second furnace, with its air-flow, enables thermometers to be easily and
safely calibrated.
A comprehensive manual accompanies each delivery.

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Dual Furnace Models M17705, N17706 & 17707 Iss.09 –12/14
THE SODIUM HEAT-PIPE FURNACE, MODEL 17705
FINAL PART OF THE COMMISSIONING INSTRUCTIONS
The initial slow temperature ramp is maintained until the temperature reaches 450°C. Impose a heat-pipe set-point
of 500°C and set the over-temperature controller to 550°C. Allow 1 to 2 hours for the furnace to stabilise and then
reduce the over-temperature cut-out setting until the relay trips and thus switching off the furnace.
Allow the furnace to cool and isolate it from the electricity supply.
At the rear are two water connections; these should be connected to a controllable supply and a flow of 1 to 2 litres
of water per minute established - this prevents the top of the cabinet being overheated at high furnace temperatures.
Run the water for 1 hour to check the furnace for absence of leaks (the floor underneath the cabinet should be
inspected).
The 17705 furnace is now ready for use.
N.B. The sodium heat-pipe incorporated in Model 17705 has a life of about 1000 hours at 1100°C, limited by the
Inconel containment.
It should endure operation for at least 10,000 hours at 1000°C.