TA Instruments TGA 2950 User manual

TA I NSTRUMENTS TGA 2950 i
Thermal Analysis & Rheology
TGA 2950
Thermogravimetric Analyzer
Operator’s Manual
PN 925602.001 Rev. D (Text and Binder)
PN 925602.002 Rev. D (Text Only)
Issued July 2000

TA I NSTRUMENTS TGA 2950ii
©1995, 1996, 1997, 2000 by
TA Instruments, Inc.
109 Lukens Drive
New Castle, DE 19720
Notice
The material contained in this manual is be-
lieved adequate for the intended use of this
instrument. If the instrument or procedures are
used for purposes other than those specified
herein, confirmation of their suitability must be
obtained from TA Instruments. Otherwise, TA
Instruments does not guarantee any results and
assumes no obligation or liability. This publica-
tion is not a license to operate under or a
recommendation to infringe upon any process
patents.
TA Instruments Operating Software and Mod-
ule, Data Analysis, and Utility Software and
their associated manuals are proprietary and
copyrighted by TA Instruments, Inc. Purchasers
are granted a license to use these software
programs on the module and controller with
which they were purchased. These programs
may not be duplicated by the purchaser without
the prior written consent of TA Instruments.
Each licensed program shall remain the exclu-
sive property of TA Instruments, and no rights
or licenses are granted to the purchaser other
than as specified above.

TA I NSTRUMENTS TGA 2950 iii
Table of Contents
Notes, Cautions, and Warnings ................ xii
Hotline Numbers........................................xiv
Safety............................................................xv
Using This Manual.................................. xviii
CHAPTER 1: Introducing
the TGA 2950 ............................................1-1
Introduction................................................. 1-3
Components..........................................1-4
The 2950 Instrument...................................1-5
2950 Display ........................................ 1-5
2950 Keypad ........................................ 1-6
HEATER Switch ......................... 1-10
POWER Switch ...........................1-10
Accessories ...............................................1-11
Gas Switching Accessory...................1-11
Other Accessories ..............................1-11
Specifications............................................1-12

TA I NSTRUMENTS TGA 2950iv
Table of Contents
(continued) CHAPTER 2: Installing
the TGA 2950 ............................................ 2-1
Unpacking/Repacking the 2950................... 2-3
Unpacking the 2950 .............................. 2-3
Repacking the 2950............................... 2-6
Installing the Instrument ............................. 2-7
Inspecting the System........................... 2-8
Choosing a Location ............................ 2-9
Filling the Heat Exchanger................. 2-10
Connecting Cables and Gas Lines...... 2-12
Heat Exchanger Cable
and Water Lines........................... 2-12
GPIB Cable.................................. 2-15
Purge Lines.................................. 2-17
Cooling Gas Line......................... 2-18
Power Cable................................. 2-19
Unpacking the Balance ............................. 2-20
Installing the Hang-Down Wires .............. 2-22
Aligning the Sample
Hang-Down Wire ............................... 2-25
Adjusting the Sample Platform................. 2-29
Starting the 2950........................................ 2-30
Shutting Down the 2950 ............................ 2-32

TA I NSTRUMENTS TGA 2950 v
Table of Contents
(continued) CHAPTER 3: Running Experiments..... 3-1
Overview..................................................... 3-3
Before You Begin ................................3-3
Calibrating the TGA ...................................3-5
Temperature Calibration ...................... 3-5
Weight Calibration...............................3-6
Sample Platform Calibration ................ 3-6
Running a TGA Experiment.......................3-7
Experimental Procedure.......................3-7
Preparing Samples............................... 3-8
Selecting Sample and Tare Pans....3-8
Taring the Sample Pan...................3-9
Automatic Tare ..................... 3-10
Manual Tare ..........................3-10
Loading the Sample............................3-11
Setting Up an Experiment .................. 3-14
Setting Up Accessories ...................... 3-15
Using the Air Cool Option.......... 3-16
Using a Purge Gas ...................... 3-16
Using the Gas
Switching Accessory .................. 3-19
Starting an Experiment.......................3-20

TA I NSTRUMENTS TGA 2950vi
Table of Contents
(continued)
Stopping an Experiment.....................3-21
Unloading the Sample ................. 3-21
Use in an Oxygen-Free Atmosphere.........3-22
Purge Gas System...............................3-22
Instrument Set-Up .............................. 3-23
CHAPTER 4: Technical Reference .......4-1
Description of the TGA 2950 .....................4-3
Components......................................... 4-5
Balance .......................................... 4-6
Sample Loading Assembly............ 4-8
Furnace .......................................... 4-9
TGA Standard Furnace ...........4-9
EGA Furnace ........................ 4-11
Cabinet.........................................4-13
Heat Exchanger............................ 4-15
Theory of Operation ................................. 4-16
Status Codes .............................................4-17

TA I NSTRUMENTS TGA 2950 vii
Table of Contents
(continued)
CHAPTER 5: Maintenance
and Diagnostics ......................................... 5-1
Overview..................................................... 5-3
Routine Maintenance .................................. 5-4
Inspection .............................................5-4
Cleaning the Instrument ....................... 5-4
Cleaning the Furnace Housing .............5-5
TGA Standard Furnace Only.........5-5
Heat Exchanger .................................... 5-6
Maintaining Heat
Exchanger Coolant ........................5-6
Draining and Refilling
the Water Reservoir.......................5-6
Replacing the Thermocouple......................5-9
Removing and
Reinstalling the Furnace ...........................5-11
Furnace Removal ...............................5-11
Furnace Replacement ......................... 5-14
Diagnosing Power Problems.....................5-16
Fuses...................................................5-16
Power Failures....................................5-18

TA I NSTRUMENTS TGA 2950viii
Table of Contents
(continued)
TGA Test Functions ................................. 5-19
The Confidence Test .......................... 5-19
Replacement Parts .................................... 5-21
Appendix A: Ordering Information ..... A-1
Appendix B: High Resolution
TGA Option.............................................. B-1
Overview.................................................... B-5
Option Installation ..................................... B-6
Using Hi-ResTM TGA................................. B-7
Background ......................................... B-7
The TA Instruments Hi-ResTM
Technique............................................ B-8
The Hi-ResTM Ramp Segment .................... B-9
Calcium Oxalate Example Scans ...... B-13
Advanced Hi-ResTM Techniques .............. B-18
What Can Be Resolved and
What Cannot?.................................... B-18
Unresolved Transitions ..................... B-19
Selecting a Hi-ResTM Technique ....... B-22

TA I NSTRUMENTS TGA 2950 ix
Table of Contents
(continued)
Dynamic Rate Hi-ResTM Ramp.......... B-22
Constant Reaction Rate
Hi-ResTM Ramp.................................. B-23
Weight Gain Experiments ................. B-26
Signature Analysis ............................ B-27
Sample Quantity and Orientation...... B-28
Exposed Surface Area ................ B-28
Bubble Formation ....................... B-29
Thermocouple Placement ........................ B-32
Data Analysis Effects .............................. B-32
Derivative Plots ....................................... B-33
Adjusting Heating Rate ........................... B-34
Adjusting Resolution Setting................... B-37
Useful Resolutions Settings .............. B-39
Temperature Calibration.......................... B-41
Hi-ResTM Transition Temperatures ... B-42
Hi-ResTM Sensitivity Segment ................. B-43

TA I NSTRUMENTS TGA 2950x
Table of Contents
(continued)
Understanding Sensitivity Setting..... B-44
Adjusting Sensitivity in
Dynamic Rate Mode ......................... B-45
Adjusting Sensitivity in Constant
Reaction Rate Mode.......................... B-47
Abort Segment......................................... B-51
Stepwise Isothermal Heating............. B-53
Hi-ResTM TGA Examples......................... B-58
Mixture of Bicarbonates.................... B-58
Dynamic Rate Scans................... B-59
Varying Resolution Setting ........ B-61
Varying Sensitivity Setting......... B-62
Constant Reaction Rate Scans .... B-63
Stepwise Isothermal Scans ......... B-65
Monosodium Glutamate.................... B-68
Banana Taffy..................................... B-69
Plastic Laboratory Tubing................. B-71
References ............................................... B-75

TA I NSTRUMENTS TGA 2950 xi
Table of Contents
(continued)
APPENDIX C: TGA 2950
Autosampler Option ................................ C-1
Introducing the Auto TGA......................... C-3
Getting Started ........................................... C-4
The TGA 2950 Instrument......................... C-6
Calibrating the Auto TGA ....................... C-10
Running Experiments .............................. C-11
Preparing the Samples....................... C-12
Selecting Sample
and Tare Pans ............................. C-12
Taring the Sample Pans .............. C-13
Loading the Samples ......................... C-16
Setting Up an Experiment ................. C-18
Manual Operation ............................. C-19
Tracking the TGA
Autosampler Status ........................... C-19
Interrupting a Run ............................. C-20

TA I NSTRUMENTS TGA 2950xii
Table of Contents
(continued)
Appendix D: TGA 2950
EGA Furnace Option .............................. D-1
Introducing the EGA Furnace.................... D-3
EGA Furnace Specifications............... D-5
Installing the EGA Furnace ....................... D-6
First-Time Installation ........................ D-6
Removing and Reinstalling the
EGA Furnace .................................... D-14
EGA Furnae Removal................. D-14
EGA Furnace Installation ........... D-16
Connecting the Spectrometer................... D-18
Using the EGA Furnace........................... D-21
Cleaning the Quartz Furnace Tube.......... D-22
Index............................................................I-1

TA I NSTRUMENTS TGA 2950 xiii
Notes, Cautions,
and Warnings
This manual uses NOTES, CAUTIONS, and
WARNINGS to emphasize important and
critical instructions.
A NOTE highlights important information about
equipment or procedures.
A CAUTION emphasizes a procedure that may
damage equipment or cause loss of data if not
followed correctly.
A WARNING indicates a procedure that
may be hazardous to the operator or to the
environment if not followed correctly.
NOTE:
tt
tt
t CAUTION:
! WARNING

TA I NSTRUMENTS TGA 2950xiv
Hotlines
To TA Instruments
For Technical Assistance........ [phone]
To Order Instruments
and Supplies............................ [phone]
For Service Inquiries............... [phone]
Sales ...................................... [phone]

TA I NSTRUMENTS TGA 2950 xv
Safety
Electrical Safety
You must unplug the instrument before doing
any maintenance or repair work; voltages
exceeding 120 volts AC are present in this
system.
High voltages are present in this instru-
ment. If you are not trained in electrical
procedures, do not remove the cabinet
covers unless specifically instructed to do
so in the manual. Maintenance and repair
of internal parts must be performed only by
TA Instruments or other qualified service
personnel.
After transport or storage in humid condi-
tions, this equipment could fail to meet all
the safety requirements of the safety
standards indicated. Refer to the NOTE on
page 2-9 for the method used to dry out
the equipment before use.
Chemical Safety
Use only the purge gases listed in Table 1.4 in
Chapter 1. Use of other gases could cause
damage to the instrument or injury to the
operator.
Do not use hydrogen or any other explosive
gas in the TGA 2950 furnace or the TGA
2950 EGA furnace.
Oxygen can be used as a purge gas in the TGA
2950. However, the furnace must be kept
clean so that volatile hydrocarbons (which
might combust) are removed.
! WARNING
! WARNING
! WARNING
! WARNING

TA I NSTRUMENTS TGA 2950xvi
Safety
(continued)
The TGA 2950 furnace assembly contains a
layer of refractory ceramic fiber (RCF)
insulation. This insulation is completely
encapsulated within the ceramic subassem-
bly, which is not meant to be disassembled.
If the subassembly should break in such a
way as to expose the RCF insulation, we
recommend that you dispose of it as you
would any refractory material.
If you are routinely evaluating materials in
the TGA that lose a large amount of volatile
hydrocarbons (
e.g. , lubricating oils), you
need to clean the furnace more frequently
to prevent dangerous buildup of debris in
the furnace.
If you are using samples that may emit
harmful gases, vent the gases by placing
the instrument near an exhaust.
The TGA 2950 EGA furnace assembly also
contains refractory ceramic fiber (RCF)
insulation. This insulation is enclosed
within the furnace housing. The furnace
housing should only be disassembled for
replacement of EGA furnace sample tube or
furnace assemblies. Refer to instructions
provided with the sample tube or furnace
replacement kits for procedures for han-
dling RCF insulation.
! WARNING
! WARNING
! WARNING
! WARNING

TA I NSTRUMENTS TGA 2950 xvii
Thermal Safety
After running an experiment, allow the open
furnace and thermocouple to cool down before
you touch them.
During a sample run, the furnace base (see
Figure 1.1) can be hot enough to burn skin.
Avoid contact with the furnace base during
experiments.
Mechanical Safety
Keep your fingers and all other objects out
of the path of the furnace when it is mov-
ing. The furnace seal is very tight.
! WARNING
! WARNING

TA I NSTRUMENTS TGA 2950xviii
Using This Manual
Chapter 1 Describes your TGA 2950
instrument and its acces-
sories and specifications.
Chapter 2 Describes how to unpack
and install the TGA and
how to connect the TGA
to the rest of your system.
Chapter 3 Describes how to run
TGA experiments and set
up the accessories.
Chapter 4 Provides technical
information and explains
prin-ciples of TGA
operation.
Chapter 5 Describes how to perform
routine maintenance,
replace the thermocouple,
remove and reinstall the
furnace, and diagnose
power problems; also
provides an explanation
of the confidence test.
Appendix A Lists TA Instruments
offices that you can
contact to place orders,
receive technical assis-
tance, and request service.
Appendix B Describes the High
Resolution option includ-
ing installation, useage,
applications, etc.

TA I NSTRUMENTS TGA 2950 xix
Using This Manual
(continued)
Appendix C Provides instructions
needed to operate the
TGA Autosampler option
to automatically load and
run samples.
Appendix D Provides instructions
needed to install and use
the EGA furnace with the
TGA 2950.

TA I NSTRUMENTS TGA 2950xx