Isotech 875 Operating Manual

FLUIDISED CALIBRATION

BATH MODEL 875

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.

Page 1 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

CONTENTS

GUARANTEE....................................................................................................................................................................................... 3

EMC INFORMATION ......................................................................................................................................................................... 4

ELECTRICAL SAFETY ......................................................................................................................................................................... 4

ENVIRONMENTAL RATINGS ........................................................................................................................................................ 4

CAUTIONARY NOTE ......................................................................................................................................................................... 5

HEALTH AND SAFETY INSTRUCTIONS .......................................................................................................................................... 6

INTRODUCTION ............................................................................................................................................................................... 7

MAJOR FEATURES .............................................................................................................................................................................. 8

SPECIFICATION ................................................................................................................................................................................. 9

THEORY OF OPERATION ............................................................................................................................................................... 10

UNPACKING AND INITIAL INSPECTION ..................................................................................................................................... 11

ASSEMBLY ......................................................................................................................................................................................... 12

USING THE TEMPERATURE CONTROLLER ................................................................................................................................. 13

FRONT PANEL LAYOUT ............................................................................................................................................................. 13

The Temperature Controller .................................................................................................................................................... 13

Altering the Setpoint ................................................................................................................................................................. 13

ADVANCED CONTROLLER FEATURES ..................................................................................................................................... 13

Setpoint Ramp Rate ................................................................................................................................................................... 13

Instrument Address ................................................................................................................................................................... 14

Monitoring the Controller Status .............................................................................................................................................. 14

Units .......................................................................................................................................................................................... 14

DIAGNOSTIC ALARMS ................................................................................................................................................................. 15

Controller Error Messages ........................................................................................................................................................ 15

INITIAL RUNNING ........................................................................................................................................................................... 16

OPTIMISATION OF THE BATH'S PERFORMANCE ....................................................................................................................... 17

MAINTENANCE ............................................................................................................................................................................... 18

AIR FLOW SETTINGS ....................................................................................................................................................................... 19

SAFETY FEATURES ........................................................................................................................................................................... 20

ACCURACY OF MEASUREMENT, FIXED POINT METHOD ........................................................................................................ 21

TOTAL ACCURACY OF MEASUREMENT ...................................................................................................................................... 21

USING THE PC INTERFACE ............................................................................................................................................................ 22

Connections .............................................................................................................................................................................. 22

Using the Interface .................................................................................................................................................................... 22

CAL NOTEPAD ................................................................................................................................................................................. 23

Minimum System Requirements ............................................................................................................................................... 23

Development ............................................................................................................................................................................ 23

License ...................................................................................................................................................................................... 23

Installing Cal NotePad ............................................................................................................................................................... 24

Starting Cal NotePad ................................................................................................................................................................ 24

Protocol .................................................................................................................................................................................... 24

COMPARISON CALIBRATION ........................................................................................................................................................ 25

REALISING THE FOLLOWING FIXED POINTS: INDIUM, LEAD, ZINC, AND ALUMINIUM .................................................... 26

FREEZING THE TIN CELL ............................................................................................................................................................... 27

Typical Melt/Freeze Sequence .................................................................................................................................................. 28

CELL HANDLING ............................................................................................................................................................................. 29

CELL KIT........................................................................................................................................................................................ 29

Cell Basket (Short) General Assembly ...................................................................................................................................... 30

Type B Optimal Cell Basket General Assembly ........................................................................................................................ 31

Type C Optimal Cell Basket General Assembly ....................................................................................................................... 32

FAULT FINDING............................................................................................................................................................................... 33

Figure 1: Fluidised Bath Filter & Case General Arrangement ................................................................................................... 34

Figure 2: Fluidised Bath Air System ........................................................................................................................................... 35

Figure 3: Fluidised Bath Equalising Block Handbook Assembly ................................................................................................ 36

Figure 4: Test of Equalising Block Assembly ............................................................................................................................. 37

Calibration Tube ....................................................................................................................................................................... 38

Front & Rear Elevation of 875 Fluidised Bath Cabinet .............................................................................................................. 39

Page 2 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

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 3 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

Symbol Identification

Publication

Description

ISO3864

Caution (refer to handbook)

IEC 417

Caution, Hot Surface

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.

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 degrees 2

ENVIRONMENTAL RATINGS

Operating Temperature 5-50°C

Relative Humidity 5-95%, non condensing

Page 4 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

CAUTIONARY NOTE

ISOTECH PRODUCTS ARE INTENDED FOR USE BY TECHNICALLY TRAINED AND COMPETENT
PERSONNEL FAMILIAR WITH GOOD MEASUREMENT PRACTICES.

IT IS EXPECTED THAT PERSONNEL USING THIS EQUIPMENT WILL BE COMPETENT IN THE MANAGEMENT
OF APPARATUS WHICH MAY BE POWERED OR UNDER EXTREMES OF TEMPERATURE. THEY MUST BE
ABLE TO APPRECIATE THE HAZARDS WHICH MAY BE ASSOCIATED WITH AND THE PRECAUTIONS TO BE
TAKEN WITH, SUCH EQUIPMENT.

Page 5 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

HEALTH AND SAFETY INSTRUCTIONS

1. Read this entire handbook 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 without disconnecting it from the supply and leaving time for it to reach

ambient temperatures.

8. Do not use the apparatus outside its recommended temperature range.

9. There are no user serviceable parts inside. Contact your nearest Isotech agent for repair.

10. Ensure materials, especially flammable materials are kept away from hot parts of the apparatus to prevent fire

risk.

11. Compressed air is dangerous and should only be used by competent, qualified personnel.

Page 6 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

INTRODUCTION

The 875 fluidised-powder calibration furnace has been developed to meet the need for a single medium to cover the
range 50°C to 700°C with good stability and uniformity. It represents a major step forward in temperature calibration
technology.

Fluidised furnaces normally consist of a container of aluminium oxide powder with a porous base-plate. Sufficient air
is passed through the plate to motivate the powder bed into a fluid-like state which means that it will flow, display
buoyancy effects and transfer heat well. However, unlike a fluid, it does not have a freezing or boiling point other
than those of the constituents of the system. This is a very valuable attribute and allows a wide temperature range to
be covered. Heat to the furnace is supplied using electrical immersion heaters.

The advantages of a fluidised bed furnace over traditional methods are:

i) Its operation does not involve evolution of toxic or inflammable fumes.
ii) It can cover a wide temperature range.
iii) It can have a large working volume.
iv) The fluidised medium can transfer heat much more efficiently than an air circulation furnace.
v) A fluidised furnace can have a rapid response to change in set point and lends itself to unattended automatic

operation.

Disadvantages of fluidised baths that have been encountered in the past include:

(i) Good temperature stability and uniformity could not be achieved in the fluidised medium, but were obtained by

inhibiting the fluidising action of the powder around the work pieces, either locally or completely, by collapsing

the bath at the desired temperature.
(ii) Furnaces leaked powder which migrated to other working areas.
(iii) Some units required air assisted exhaust systems with large flows (125 litres/min, 50 psi).

By design and careful control of the air and thermal systems, the 875 Advanced Calibration Furnace has minimised
these disadvantages. It spans a large temperature range (alternatively requiring three liquid baths); it can be used for
both the comparison method of calibration (using a standard thermometer) and the fixed point method (e.g. melting
point of zinc) by simply changing the thermometer carrier assembly (removal of which also gives access to the
furnace). It requires only a low-pressure, low-flow air supply, obtainable from portable electric air pumps. The
exhausted air passes out of the sealed furnace via a self-cleaning filter and is piped away, thereby ensuring a cleaner
working atmosphere.

Page 7 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

MAJOR FEATURES

1. The furnace is a sealed system; therefore, powder contamination of surrounding areas is eliminated, enhancing

flexibility of location.

2. Using a simple self-cleaning filter in a sealed system eases maintenance requirements on powder levels and

fume extraction systems.

3. A sealed system minimises ingress of moisture during non-operational periods. Moisture can cause

temperature instability and can give rise to significant amounts of steam when a furnace is operated after a

dormant period.

4. The air flow rate required is low because of the unique design features. This permits flexibility in the range of

air supplies applicable, from factory installations to small portable pumps.

5. The exhausted filtered air, having a small flow rate, can be piped outside the laboratory using a small bore

piping (plastic pipe downstream of 2 metres of copper pipe), or, if operating in less sensitive conditions can be

left to exhaust directly from filter outlet.

6. There are few moving parts, and none associated with the air and thermal systems controlling the furnace's

operation. The unit is more reliable and consistent than furnaces with electro-pneumatic air control systems.

7. The furnace is designed to be readily adaptable to suit most customer requirements and it can serve as a multi-

role calibration furnace.

8. The immersion depth of 470mm (18.5") has a temperature distribution good enough to enable long or large

devices to be calibrated.

9. The furnace's independence from peripheral equipment and its clean operation enable it to be easily moved on

its castors for use in alternative locations.

10. The furnace design is based on long experience of calibration.

Page 8 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

Overall Size:

Depth: 640mm

Width: 580mm

Height: 880mm (To top of body)

Height: 1570mm (overall)

Furnace Container:

Stainless Steel

Working Volume:

67mm diameter, 457mm deep

Temperature Range:

50°C to 700°C

Heaters:

3 x 1kW wired in parallel. Heated length of each is 2135mm

SPECIFICATION

Page 9 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

THEORY OF OPERATION

Temperature stability and uniformity is achieved in the 875 Fluidised Calibration Bath by the following means:-

1. Loss of heat from the container is minimised by effective insulation of its outer surfaces with high temperature

user friendly insulation.

2. A novel means of diminishing the mass flow of air to the furnace as its temperature increases has been

developed. This reduction is needed to counter-balance the volume expansion due to increasing the
temperature of the air towards that of the furnace. The method devised involves controlled pre-heating of
the air by passing it through a tube immersed in the fluidised powder. The air is then regulated to the
required flow rate by a calibrated orifice (patented). The technique requires no moving parts; self-adjustment
to the thermal conditions of the furnace results in a consistent and reliable performance.

3. The degree of fluidisation and the flow pattern throughout the fluidised medium have been more strictly

controlled than in conventional fluidised baths. In the 875 system, the fluidisation is graded across the furnace
to promote efficient heat transfer, mixing around the heaters and temperature stability at the work pieces.
The flow of the fluidised powder is confined to a fixed route by an internally mounted baffle tube which is
coaxial with the container (patented). The tube surrounds the work pieces and is similar in design to that
found in high-grade liquid calibration baths.

Page 10 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

UNPACKING AND INITIAL INSPECTION

Custom-designed packaging is used for this unit, but, as accidents can still happen in transit, you are advised, after
unpacking to inspect the unit for any sign of shipping damage and confirm that your delivery is in accordance with the
packing note and check list.

If you find any damage, or that part of the delivery is missing, immediately notify Isotech (or our agent) and the
carrier. Keep the packaging, if damaged, for possible inspection by an insurance assessor.

Page 11 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12

ASSEMBLY

Please check that you have the following parts:

1. Main cabinet pre-commissioned with alumina powder.

2. Assembled filter unit.

3. Temperature controller unit.

4. Thermocouple connecting cable.

5. Electricity supply cable for bath.

6. 2kg of alumina powder.

7. Gasket and spares.

8. Handbook.

To transport the 875 Fluidised Bath, it is necessary to remove from the bath the assembled air filter in its outer cover
and to disconnect the controller.

Therefore, on arrival, you will need to reassemble these items as follows:

i) Remove the bung from the furnace exhaust outlet on top of the bath.

ii) Place the gasket around the base of the exhaust assembly as shown here.

iii) Place the outer cover of the filter assembly on the gasket and lock it into place using

the attached spring clips.

iv) Connect a metal tube to the outlet of the filter if it is intended to take the exhausted

air outside the immediate working environment. The outlet has an internal screw­thread (¼" BSP) for this purpose.

v) Connect the temperature controller to the furnace, the furnace and controller to a suitable electrical supply

and the thermocouple cable between controller and furnace.

vi) Connect a clean, dry compressed air supply to the furnace (1.2 bar gauge, 50 litres/minute).

vii) This unit becomes very hot in use and should be sited accordingly.

Page 12 of 39

Fluidized Calibration Bath Model 875 Iss.05 – 05/12