tga 2050 ce operator's manual · 2015. 9. 7. · ta instruments tga 2050 ce i tga 2050 ce...

TA INSTRUMENTS TGA 2050 CE I

TGA 2050 CE

Thermogravimetric Analyzer

Operator’s Manual

PN 825603.001 Rev. D (Text and Binder)PN 825603.002 Rev. D (Text Only)Issued July 2000

TA Instruments Thermal Analysis & Rheology

A SUBSIDIARY OF WATERS CORPORATION

109 Lukens Drive New Castle, DE 19720

TA INSTRUMENTS TGA 2050 CEII

©1996, 1997, 1999, 2000by TA Instruments, Inc.109 Lukens DriveNew Castle, DE 19720

Notice

The material contained in this manual is be-lieved adequate for the intended use of thisinstrument. If the instrument or procedures areused for purposes other than those specifiedherein, confirmation of their suitability must beobtained from TA Instruments. Otherwise, TAInstruments does not guarantee any results andassumes no obligation or liability. This publica-tion is not a license to operate under or arecommendation to infringe upon any processpatents.

TA Instruments Operating Software and Mod-ule, Data Analysis, and Utility Software andtheir associated manuals are proprietary andcopyrighted by TA Instruments, Inc. Purchas-ers are granted a nonexclusive, nontransferablelicense to use these software programs on themodule and controller with which they werepurchased. These programs may not be du-plicated by the purchaser without the priorwritten consent of TA Instruments. Eachlicensed program shall remain the exclusiveproperty of TA Instruments, and no rights orlicenses are granted to the purchaser other thanas specified above.

TA INSTRUMENTS TGA 2050 CE III

Table of ContentsNotes, Cautions, and Warnings...............viii

Hotlines ........................................................ix

Safety.............................................................x

Using This Manual.....................................xvi

CHAPTER 1:Introducing the 2050 CE.......................... 1-1

Introduction................................................ 1-3

Components ............................................... 1-4

The 2050 CE Instrument ............................. 1-6

Automatic Keypad Functions .............. 1-9Front Panel lights ................................. 1-9

Accessories .............................................. 1-10

Gas Switching Accessory ................. 1-10Other Accessories ............................. 1-10

Specifications ........................................... 1-11

CHAPTER 2: Installing the 2050 CE..... 2-1

Unpacking/Repacking the 2050 CE ............ 2-3

Unpacking the 2050 CE ....................... 2-3

Repacking the 2050 CE ........................ 2-6

Installing the Instrument ............................ 2-7

TA INSTRUMENTS TGA 2050 CEIV

Table of Contents(continued)

Inspecting the System ................................ 2-8

Choosing a Location ........................... 2-9

Filling the Heat Exchanger................ 2-10

Connecting Cables and Lines ............ 2-12

Heat ExchangerWater Lines ................................ 2-12

GPIB Cable .......................... 2-14

Purge Lines........................................ 2-16Cooling Gas Line ........................ 2-18

Power Cable ...................................... 2-19

Unpacking the Balance ............................. 2-20

Starting the 2050 CE ................................. 2-22

Installing the Hang-Down Wires ............. 2-24

Aligning the SampleHang-Down Wire .............................. 2-28

Adjusting the Sample Platform ......... 2-32

Shutting Down the Instrument .................. 2-33

CHAPTER 3: RunningExperiments............................................... 3-1

Overview .................................................... 3-3

Before You Begin ............................... 3-4

TA INSTRUMENTS TGA 2050 CE V


Calibrating the TGA ................................... 3-5

Weight Calibration ............................... 3-5

Temperature Calibration ...................... 3-5

Running a TGA Experiment ....................... 3-6

Experimental Procedure ....................... 3-6

Preparing the Sample .......................... 3-7

Selecting Sampleand Tare Pans ................................ 3-7

Taring the Sample Pan ................... 3-8Automatic Tare ....................... 3-9Manual Tare ............................ 3-9

Loading the Sample ............................ 3-10

Setting Up an Experiment .................. 3-14

Setting Up Accessories ..................... 3-15

Using a Purge Gas ....................... 3-15Using the Air Cool Option .......... 3-18Using the Gas SwitchingAccessory .................................... 3-18

Starting an Experiment ....................... 3-20

Stopping an Experiment ..................... 3-21

Unloading the Sample ................. 3-22

Use in an Oxygen-Free Atmosphere ......... 3-23

TA INSTRUMENTS TGA 2050 CEVI


Purge Gas System............................... 3-23

Instrument Setup ................................ 3-24

CHAPTER 4: Technical Reference......... 4-1

Description of the TGA 2050 CE .............. 4-3

Components.......................................... 4-5

Balance .......................................... 4-6Sample Loading Assembly ............ 4-8Furnace .......................................... 4-9Cabinet ......................................... 4-11Heat Exchanger............................ 4-13

Theory of Operation ................................. 4-14

Status Codes ............................................ 4-15

CHAPTER 5: Maintenanceand Diagnostics......................................... 5-1

Overview ..................................................... 5-3

Routine Maintenance .................................. 5-4

Inspection ............................................. 5-4

Cleaning the Instrument Keypad .......... 5-4

Cleaning the QuartzFurnace Tube........................................ 5-4

TA INSTRUMENTS TGA 2050 CE VII


Heat Exchanger ....................................5-7

Maintaining HeatExchanger Coolant ........................5-7Draining and Refilling theWater Reservoir .............................5-7

Replacing the Thermocouple ....................5-10

Diagnosing Power Problems .....................5-12

Fuses ...................................................5-12

Power Failures ....................................5-13

TGA 2050 CE Test Functions ..................5-14

The Confidence Test ..........................5-14

Replacement Parts ....................................5-16

Appendix A: Ordering Information ..... A-1

Address List ............................................... A-1

Index ............................................................ I-1

TA INSTRUMENTS TGA 2050 CEVIII

Notes, Cautions,and Warnings

This manual uses NOTES, CAUTIONS, andWARNINGS to emphasize important andcritical instructions.

A NOTE highlights important information aboutequipment or procedures.

A CAUTION emphasizes a procedure that maydamage equipment or cause loss of data if notfollowed correctly.

A WARNING indicates a procedure that maybe hazardous to the operator or to theenvironment if not followed correctly.

NOTE:

!WARNING

t CAUTION:

TA INSTRUMENTS TGA 2050 CE IX

Hotlines

To TA Instruments Thermal Analysis

For Technical Assistance ........ (302) 427-4070

To Order Instruments andSupplies .................................. (302) 427-4040

For Service Inquiries............... (302) 427-4050

General Information ................ (302) 427-4000

TA INSTRUMENTS TGA 2050 CEX

SafetyThis equipment has been designed to complywith the following standards on safety:

• IEC 1010-1/1990 + A1/1992 + A2/1995• IEC 1010-2-010/1992 + A1/1996• EN 61010-1/1993 + A2/1995• EN 61010-2-010/1994• UL 3101-1, First Edition.

CE Compliance

In order to comply with the ElectromagneticCompatibility standards of the European Coun-cil Directive 89/336/EEC (EMC Directive) andDirective 73/23/EEC on safety as amended by93/68/EEC, the following specifications apply tothe TGA 2050 CE:

• Safety:EN 61010-1/1993 + A2/1995EN 61010-2-010/1994

• Emissions:EN 55022/1995Class B (30-1000 MHz) Radiated

EN 55022/1995Class B (0.15-30 MHz) Conducted

(continued on next page)

TA INSTRUMENTS TGA 2050 CE XI

• Immunity:EN 50082-1: 1992, ElectromagneticCompatibility-Generic immunity standardPart 1. Residential, commercial, and lightindustry.

— IEC 801-2: 1991, 8 kV air discharge.No change of state.

— IEC 801-3: 1984, 27-500 MHz, 3 V/m.No response above 10.00 µg sampleweight and 2.00°C sample temperature.

— IEC 801-4: 1988 Fast transientscommon mode 1 kVac power.No change of state.

TA INSTRUMENTS TGA 2050 CEXII

Instrument Symbols

The following label is displayed on the TGA2050 CE instrument for your protection:

Symbol Explanation

This symbol, on the frontof the TGA 2050 CEfurnace, indicates that ahot surface may bepresent. Do not touch thisarea or allow any materialthat may melt or burncome in contact with thishot surface.

Please heed the warning labels and take thenecessary precautions when dealing with thoseparts of the instrument. The TGA 2050 CEOperator's Manual contains cautions andwarnings that must be followed for your ownsafety.

Electrical Safety

You must unplug the instrument before doingany maintenance or repair work; voltagesexceeding 110 Vac are present in this system.

High voltages are present in this instrument.If you are not trained in electrical procedures,do not remove the cabinet covers. Main-tenance and repair of internal parts must beperformed only by TA Instruments or otherqualified service personnel.

!WARNING

TA INSTRUMENTS TGA 2050 CE XIII

Safety(continued)

After transport or storage in humid condi-tions, this equipment could fail to meet theleakage current requirements of the safetystandards indicated. Refer to the WARNINGon page 2-9 for the method used to dry outthe equipment before use.

Chemical Safety

Use only the purge gases listed in Table 1.2 inChapter 1. Use of other gases could causedamage to the instrument or injury to theoperator.

Do not use hydrogen or any other explosivegas in the TGA 2050 CE furnace.

If you are using samples that may emit harm-ful gases, vent the gases by placing theinstrument near an exhaust.

If you are routinely evaluating materials in theTGA that lose a large amount of volatilehydrocarbons (e.g., lubricating oils), you needto clean the furnace more frequently toprevent dangerous buildup of debris in thefurnace. This is particularly important if oxygenis used as a purge gas in the TGA 2050. SeeChapter 5 for instructions.

!WARNING

!WARNING

!WARNING

!WARNING

TA INSTRUMENTS TGA 2050 CEXIV

Safety(continued)

The TGA 2050 CE furnace assembly alsocontains refractory ceramic fiber (RCF)insulation. This insulation is enclosed withinthe furnace housing. The furnace housingshould only be disassembled for replacementof EGA furnace sample tube or furnaceassemblies. Refer to instructions providedwith the sample tube or furnace replacementkits for procedures for handling RCF insula-tion.

Thermal Safety

After running an experiment, allow the openfurnace and thermocouple to cool down beforeyou touch them.

During a sample run, the furnace base can behot enough to burn skin. Avoid contact withthe furnace base during experiments.

Mechanical Safety

Keep your fingers and all other objects out ofthe path of the furnace when it is moving. Thefurnace seal is very tight.

!WARNING

!WARNING

!WARNING

TA INSTRUMENTS TGA 2050 CE XV

Lifting the Instrument

The TGA 2050 CE is a fairly heavy instrument.In order to avoid injury, particularly to the back,please follow this advice:

Use two people to lift and/or carry theinstrument. The instrument is too heavy forone person to handle safely.

!WARNING

TA INSTRUMENTS TGA 2050 CEXVI

Using This ManualChapter 1 Describes your TGA 2050

CE instrument and itsspecifications.

Chapter 2 Describes how to connectthe TGA to the rest ofyour system and how toinstall the system.

Chapter 3 Describes how to runTGA experiments.

Chapter 4 Provides technicalinformation on theprocedures described inChapter 5 and explainsprinciples of TGA opera-tion.

Chapter 5 Describes how to performroutine maintenance,replace the thermocouple,remove and reinstall thefurnace, and diagnosepower problems; alsoprovides an explanationof the confidence test.

Appendix A Lists TA Instrumentsoffices that you cancontact to place orders,receive technical assis-tance, and request service.

Index Lists the page numbers ofimportant topics for yourreference.

TA INSTRUMENTS TGA 2050 CE 1–1

CHAPTER 1: Introducing theTGA 2050 CE

Introduction............................................. 1-3

Components ............................................ 1-4

The 2050 CE Instrument .......................... 1-6

Automatic Keypad Functions ............ 1-9Front Panel lights .............................. 1-9

Accessories ........................................... 1-10

Gas Switching Accessory ............... 1-10Other Accessories .......................... 1-10

Specifications ........................................ 1-11

Introducing the TGA 2050 CE

1–2 TA INSTRUMENTS TGA 2050 CE


IntroductionYour TA Instruments ThermogravimetricAnalyzer (TGA) 2050 CE is a thermal weight-change analysis instrument that can be used withany of the TA Instruments PC-based controllers.

The TGA 2050 CE measures the amount andrate of weight change in a material, either as afunction of increasing temperature, or isother-mally as a function of time, in a controlledatmosphere. It can be used to characterize anymaterial that exhibits a weight change and todetect phase changes due to decomposition,oxidation,or dehydration. This informationhelps the scientist or engineer identify thepercent weight change and correlate chemicalstructure, processing, and end-use performance.

Your controller is a computer that performs thefollowing functions:

• Provides an interface between you andthe analysis instruments

• Enables you to set up experiments andenter constants

• Stores experimental data• Runs data analysis programs.

The TGA 2050 CE executes thermal experi-ments that have been set up on the controller.See Figure 1.1 on the next page for an illustra-tion of a TGA system.

Introduction



Figure 1.1ThermogravimetricAnalyzer (TGA) 2050 CE withPC-Based TA InstrumentsThermal Analyzer

Components

The TGA 2050 CE has five major components,illustrated in Figure 1.2:

• The balance, which provides precisemeasurement of sample weight. Thebalance is the key to the TGA system.

• The sample platform, which loads andunloads the sample to and from thebalance.

• The furnace, which controls the sampleatmosphere and temperature.

• The cabinet, where the systemelectronics and mechanics are housed.

• The heat exchanger, which dissipatesheat from the furnace.


Figure 1.2TGA 2050 CEComponents

Introduction

Balance

Sample Platform

Furnace

Cabinet

Heat Exchanger

This label indicates that a hot surface may be present.



The 2050 CE InstrumentThe instrument keypad (Figure 1.3) containskeys that control local operations at the instru-ment (automatic balance tare, furnace elevator,sample loading platform, and experiment startand stop functions).

Figure 1.3TGA 2050 CE Keypad

Table 1.1 explains the functions of the instru-ment keys.

Experiment information and instrument constantsare entered from the controller keyboard, not theinstrument keypad.

NOTE:

Start Stop


The 2050 CE Instrument

Table 1.1Instrument KeypadFunction Keys

Key/Function Explanation

TARE Zeros the weight of anempty sample pan:automatically loads thepan from the sampleplatform, raises thefurnace to protect the panfrom air currents, weighsthe pan, stores the weightas an offset, and thenunloads the pan.

LOAD Loads a sample pan fromthe sample platform ontothe balance.

UNLOAD Unloads the sample panfrom the balance onto thesample platform.

FURNACE Toggles between thefurnace closed (up) andfurnace open (down)functions, depending onwhere the furnace is whenyou press the key. Thiskey can be pressed whilethe furnace is moving toreverse the direction ofmovement.

START Begins the experiment.This is the same functionas Start on the controller.

(table continued)



Table 1.1Instrument KeypadFunction Keys(continued)

Key/Function Explanation

STOP If an experiment isrunning, this key ends themethod normally, asthough it had run tocompletion; i.e., themethod-end conditions gointo effect, and the datathat has been generated issaved. This is the samefunction as Stop on thecontroller.

If an experiment is notrunning (the instrument isin a stand-by or method-end state), the STOP keywill halt any activity (aircool, all mechanicalmotion, etc.).


Automatic KeypadFunctions

Some of the TGA instrument keys automaticallyperform additional functions under certainconditions:

• START automatically loads the samplepan and closes the furnace, if necessary,before beginning the experiment.

• TARE, LOAD, and UNLOADautomatically open the furnace ifnecessary.

• START can be pressed while a sampleload is in progress.

Front PanelLights

The front panel green power light shows that theinstrument is on; the yellow light shows that theinstrument is ready.

The 2050 CE Instrument



Accessories

Gas SwitchingAccessory

The TA Instruments Gas Switching Accessorycan be used to turn the purge gas on and off or toswitch between two different purge gases duringTGA experiments.

Consult your Gas Switching Accessoryoperator’s manual for further instructions.

Other Accessories

The TGA can be used with many standardanalytical accessories offered by various manu-facturers, including vacuum, FTIR, gas chro-matographs, mass spectrometers, and evolvedgas analyzers. Consult the appropriate localinstrument manufacturer for further information.


Specifications

SpecificationsTable 1.2TGA 2050 CESpecifications

Temperature range 25oC to 1000oC

Thermocouple Platinel II*

Heating rate 0.1 to 50°C/min

Operating line voltage 120 volts,50/60 Hz

Energy consumption 1.5 kVA

Weight 50 lbs.

*Platinel II is a registered trademark ofEngelhard Industries.



Table 1.3Sampling System

Sample pansTypes Platinum, Alumina

(Al 203), AluminumVolume capacity Platinum: 50 µL,

100 µLAlumina: 100 µL,250 µL, 500 µLAluminum: 100 µL

Weighing capacity1 1.0 gm

Balance measurement2

Resolution 0.2 µgAccuracy < + 0.1%Ranges 100 mg range:

-10 mg to 100 mg

1000 mg range:-100 mg to 1000 mg

1 The total mechanicalcapacity of the balance is5 gm. In order to avoiddamaging the balanceassembly, never allow thetotal weight of the sample,tare weight, hang-downwires, and pans to exceed5 gm.

2 The TGA balance mecha-nism is sensitive to changesin the surrounding roomtemperature. For optimumaccuracy, you must regulatethe ambient temperature.

(table continued)

ttttt CAUTION:


Specifications

Table 1.3Sampling System(continued)

Furnace AtmospherePurge gases Helium, nitrogen,

oxygen, air, argon3

Purge rate Up to 100 cc/min

3 Do not use hydrogen orany other explosive gas inthe TGA 2050 CE. Oxygenmay be used. However, thefurnace must be kept cleanof volatile hydrocarbons toprevent combustion.

!WARNING


CHAPTER 2: Installing theTGA 2050 CE

Unpacking/Repacking the 2050 CE ............ 2-3

Unpacking the 2050 CE ....................... 2-3

Repacking the 2050 CE ........................ 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 Lines ............ 2-12

Heat ExchangerWater Lines ................................ 2-12

GPIB Cable .......................... 2-14Purge Lines........................................ 2-16

Cooling Gas Line ........................ 2-18Power Cable ...................................... 2-19

Unpacking the Balance ............................. 2-20

Starting the 2050 CE ................................. 2-22

Installing the Hang-Down Wires ............. 2-24

Aligning the SampleHang-Down Wire .............................. 2-28

Installing the TGA 2050 CE


Adjusting the Sample Platform ......... 2-32

Shutting Down the Instrument .................. 2-33


Unpacking/Repackingthe 2050 CE

Due to the delicate mechanisms contained in theTGA 2050 CE balance, the balance will be un-packed later, see page 2-20.

Refer to Figures 2.1 to 2.3 while unpacking yourinstrument.

Unpacking the2050 CE

Have an assistant help you unpack this unit.Do not attempt to do this alone.

Figure 2.1Shipping Boxes

Unpacking/Repacking the 2050 CE

NOTE:

!WARNING



1. Open the shipping carton and remove theaccessory box.

2. Remove the cardboard packing insert.

3. Stand at one end of the box with yourassistant facing you at the other end. Liftyour end of the unit out of the box as yourassistant lifts his/her end.

4. Place the unit on a lab bench with one sidehanging over the edge of the bench (seeFigure 2.2). Someone must be holdingonto the unit at all times while it is in thisposition.

Figure 2.2Removing the TGA 2050 CEFrom the Shipping Platform


5. While your assistant holds the unit, use awrench to remove the two nuts and washersfrom the bottom. Then lift and rotate theunit so that the other end hangs over theedge of the bench. Someone must holdonto the unit at all times while it is in thisposition. While your assistant holds theunit, remove the two nuts and washers fromthe other side.

6. Slide the unit completely onto the lab bench.Have your assistant hold one side up whileyou unscrew and remove the black rubbershipping feet from the bottom. Then rotatethe unit and remove the shipping feet fromthe other side in the same manner.

7. Have your assistant lift one side of the unitwhile you install two mounting feet on oneside (see Figure 2.3). Screw in about 1/4-inch of the threaded mounting post into theunit. Rotate the unit and install the tworemaining mounting feet on the unit in thesame manner.

8. Have your assistant lift the entire unit whileyou slide the plywood board out from underthe unit.

9. Turn the instrument to face front and use awrench to remove the furnace clamp fromthe unit. Retain this clamp in case theinstrument needs to be shipped in the future.

Unpacking/Repacking the 2050 CE



Figure 2.3Installing theMounting Feet

10. Follow the directions beginning on page 2-7to install the instrument before you unpackthe balance.

Repackingthe 2050 CE

To pack and ship your instrument, use thehardware retained during unpacking and reversethe instructions found on pages 2-3 to 2-5.


Installing theInstrument

Before shipment, the TGA 2050 CE instrumentis inspected both electrically and mechanicallyso that it is ready for operation upon properinstallation. Installation involves the followingprocedures, described in this chapter:

• Unpacking the instrument and itscomponents and accessory kit

• Inspecting the system for shippingdamageand missing parts

• Filling the heat exchanger• Connecting the TGA to the TA

Instruments controller• Connecting the heat exchanger water lines,

purge gas lines, accessories, and powercable

• Unpacking the balance• Installing the hang-down wires• Leveling the instrument and aligning the

hang-down wires• Adjusting the sample platform.

If you wish to have your TGA installed by a TAInstruments Service Representative, call for aninstallation appointment when you receive yourinstrument.

To avoid mistakes, read this entire chapterbefore you begin installation.

Installing the Instrument

ttttt CAUTION:



Inspectingthe System

When you receive your TGA, look over theinstrument and shipping container carefully forsigns of shipping damage, and check the partsreceived against the enclosed shipping list.

If the instrument is damaged, notify the carrierand TA Instruments immediately.

If the instrument is intact but parts are missing,contact TA Instruments.

A list of TA Instruments phone numbers can befound in Appendix A of this manual.


Choosing a LocationBecause of the sensitivity of TGA experiments,it is important to choose a location for theinstrument using the following guidelines. TheTGA should be:

In ... a temperature controlled area.... a clean, vibration-free environment.... an area with ample working

and ventilation space.(Refer to the specifications inChapter 1 for the instrument dimen-sions).

On ... a stable work surface.

Near ... a power outlet (120 volts AC, 50 or60 Hz, 15 amps). A step up/downline transformer may be required ifthe unit is operated at a higher orlower line voltage.

... your TA Instruments thermalanalysis controller.

... compressed lab air and purge gassupplies with suitable regulators andflow meters.

Away from ... dusty environments.... exposure to direct sunlight.... direct air drafts (fans, room air

ducts).... poorly ventilated areas.... noisy or mechanical vibrations.

Drying out the instrument may be needed, if ithas been exposed to humid conditions. Cer-tain ceramic materials used in this equipmentmay absorb moisture, causing leakage cur-rents to exceed those specified in the appli-cable standards (see page x) until the mois-ture is eliminated. It is important to becertain that the instrument ground is ad-equately connected to the facilities ground forsafe operation.

(continued)


!WARNING



Run the following method to dry out theinstrument (refer to Chapter 4 "Running anExperiment" for further information).

1 Equilibrate at 300°C2 Isothermal for 30 min.

Filling the Heat Exchanger

The heat exchanger contains a liquid reservoirthat supplies the instrument with coolant todissipate heat from the furnace. The coolantexits the heat exchanger through the supply line,circulates to the furnace, and comes back to thereservoir via the return line as seen in Figure 2.4(for instructions on how to connect the waterlines, turn to page 2-13). To fill the heat ex-changer, follow the directions given below.

Figure 2.4Rear Panel ofHeat Exchanger

1. Unscrew the water reservoir cap on the heatexchanger bottle (see Figure 2.5).

Water Reservoir Cap

!WARNING(cont'd)


Figure 2.5Heat Exchanger Bottle

2. Add TA Instruments TGA Conditioner (PN952377.901) into the water reservoir bottle.Refer to the instructions on the bottle for theamount of conditioner to add to the reser-voir. Then fill the bottle to the inner rim(see Figure 2.5) with distilled water.

After the system has been started, recheck thelevel of water in the reservoir bottle and refill tothe inner rim with distilled water, if necessary.

Do not put any water other than distilledwater in the heat exchanger reservoir.

3. Replace and tighten the water reservoir cap.


Fill to bottle's inner rim

NOTE:

ttttt CAUTION:



Connecting Cables and Lines

To connect the cables, water and gas lines, youwill need access to the TGA instrument’s rearpanel. All directional descriptions are written onthe assumption that you are facing the back ofthe instrument.

Connect all cables before connecting the powercords to outlets. Tighten the thumbscrews on allcomputer cables.

Whenever plugging or unplugging power cords,handle them by the plugs, not by the cords.

Protect power and communications cablepaths. Do not create tripping hazards bylaying them across accessways.

Heat ExchangerWater Lines

1. Remove the water lines from the packing.

2. Connect one end of the water line marked“SUPPLY” to the connector labeled “SUP-PLY” on the left front of the instrumentcabinet.

3. Connect the other end of the water linemarked “SUPPLY” to the connector labeled“SUPPLY” on the heat exchanger.

4. Connect one end of the unmarked water lineto the connector labeled “RETURN” on theleft front of the instrument cabinet.

NOTE:

ttttt CAUTION:

!WARNING


5. Connect the other end of the unmarkedwater line to the connector labeled “RE-TURN” on the heat exchanger.

The TGA heat exchanger has been electronicallyde-coupled from the instrument in order to meetEMC requirements and therefore must be turnedon and off manually by the operator. Rememberto turn the heat exchanger on prior to running anexperiment, and off after completion of an experi-ment. Allowing the heat exchanger to run continu-ously will not harm the instrument, but may reducethe operating life of your heat exchanger.

Figure 2.6 below illustrates the correct waterline connections for the TGA and heatexchanger.

Figure 2.6Heat ExchangerWater LineConnections


NOTE:



GPIB Cable

1. Locate the GPIB connector on the right rearof the TGA instrument (See Figure 2.8).

2. Connect the GPIB cable to the connector.The GPIB cable is the only cable that fitsinto the connector.

3. Tighten the hold-down screws on theconnector.

4. Connect the other end of the GPIB cable tothe controller or to the GPIB cable ofanother instrument connected to the control-ler.

5. Select an address from 1 to 9. Then use theaddress selector dial on the TGA connectorpanel to set the desired address. Figure 2.7shows an instrument address of 4.

If you have a multi-instrument system, eachinstrument must have a different address.

If you change the address after the TGA ispowered on, you must press the TGA’s Resetbutton to enter the new address. Wait 30seconds after releasing the Reset button; theyellow ready light should begin to glow steadily.Reconfigure the instrument.

The instrument’s GPIB address is displayed duringstart up and can also be viewed on theinstrument’s status display.

NOTE:

NOTE:


Figure 2.7Address Selector Dial(Showing an Address of 4)


(Not used withthe TGA 2050 CE)



Purge Lines

Do not use any liquid in the purge lines.

1. Locate the PURGE and BALANCE PURGEfittings on the back of the TGA instrument(Figure 2.8).

Figure 2.8TGA PURGE Fittings

!WARNING

Purge

Balance PurgePurge

(Not used withthe TGA 2050 CE)


2. Make sure that the pressure of your purgegas source does not exceed the manufactur-ers recommended pressures for flowmetersand other regulated devices you are using.

If you are using laboratory purge, rather thanbottled purge, you will need to install an externaldrier.

The use of corrosive gases in the TGA 2050 CEare not recommended.

Use of an explosive gas as a purge gas isdangerous and is not recommended for thisinstrument. For a list of the purge gases thatcan be used with the TGA instrument, seeChapter 1. Oxygen may be used. However, thefurnace must be kept clean of volatile hydrocar-bons to prevent combustion.

3. Connect a length of 1/4-inch I.D. flexibletubing from each of the PURGE fittings to aflowmeter (consult your compressed gasvendor for specific requirements). Thenconnect each flowmeter to the purge gassource.

4. The recommended setting for the purge rateis 100 cc per minute or less, with a flowdistribution of 10 percent to the balancechamber and 90 percent to the furnace.


tCAUTION:

!WARNING

NOTE:



Cooling Gas Line

1. Locate the COOLING GAS fitting, a 1/4-inch compression fitting on the left side ofthe TGA cabinet back, marked with a 120psig maximum warning label (Figure 2.9).

Figure 2.9TGA COOLINGGAS Fitting

2. Make sure your compressed lab air source isregulated to between 25 and 120 psig and isfree of oil and water vapors.

3. Connect a compressed lab air line to theCOOLING GAS fitting.

Nitrogen may also be used as a cooling gas.NOTE:

Cooling GasFitting


Power Cable

The accessory kit contains two power cords. Theferrite loaded power cord provides the TGAprotection against electromagnetic interference(EMI). To ensure best test results, this powercord must be used for the TGA instrument, whilethe standard power cord is used with the heatexchanger.

1. Make sure the TGA POWER switch, locatedon the back of the instrument, (Figure 2.10)is in the OFF position.

Figure 2.10TGA POWER Switch

2. Plug the power cable into the TGA.

Before plugging the TGA power cable into the walloutlet, make sure the instrument is compatiblewith the line voltage. Check the label on the backof the unit to verify the voltage.

3. Plug the power cable into the wall outlet.


NOTE:

ttttt CAUTION:

PowerSwitch



Unpacking the Balance

When unpacking the balance, be careful not todamage the balance arm or hang-down loops.

1. Using the 7/64-inch ball driver supplied inyour TGA accessory kit, loosen and removethe six screws securing the balance chamberfaceplate to the instrument.

2. Take off the faceplate.

3. Loosen and remove the thumbscrew holdingthe balance cover on the sample (left) sideof the balance mechanism (Figure 2.11), andtake off the cover. Repeat this step for thetare (right) side of the balance mechanism.

Figure 2.11Interior ofBalance ChamberBefore Unpacking

t CAUTION:

BalanceCover

SampleSide

TareSide

TareTube

BalanceCoverScrew

Hang-DownLoop


4. Using tweezers, remove the foam insertfrom around the screw hole (Figure 2.12):

a. Gently compress the foam with thetweezers, being careful not to touch thebalance.

b. Remove the foam insert from thebalance chamber.

Figure 2.12Removal ofFoam Insertfrom Balance Chamber

5. Replace the sample side cover and screw,being careful not to trap the hang-downloop.

6. Repeat the procedure to remove the foaminsert in the tare (right) side of the balance.

FoamInsert

Unpacking the Balance



Starting the TGA 2050 CE

1. Check all connections between the 2050 CEand the controller. Make sure each compo-nent is plugged into the correct connector.(For installation information, see Chapter 2.)

2. Press the instrument power switch, locatedon the rear of the instrument, to the ONposition. The green power light on the frontof the instrument should turn on and theyellow Ready light should flash.

3. If the green power light fails to come on,recheck the power connections to theinstrument and the power source. Also,check instrument power fuse F1 on the rearof the instrument to see if the fuse is blown.

4. Bring the instrument online with the TAcontroller.

Allow the TGA to warm up for at least 30minutes before performing an experiment.

5. Make sure the heat exchanger POWERswitch is OFF.

The accessory kit contains two power cords. Theferrite loaded power cord provides the TGAprotection against electromagnetic interference(EMI). To ensure best test results, this powercord must be used for the TGA instrument, whilethe standard power cord is used with the heatexchanger.

6. Plug the standard power cord into the heatexchanger.

NOTE:

NOTE:


7. Plug power cord into wall receptacle.

8. Turn on the power switch on the heatexchanger.

The TGA heat exchanger has been electronicallyde-coupled from the instrument in order to meetEMC requirements and therefore must be turnedon and off manually by the operator. Rememberto turn the heat exchanger on prior to running anexperiment, and off after completion of an experi-ment. Allowing the heat exchanger to run continu-ously will not harm the instrument, but may reducethe operating life of your heat exchanger.

Air trapped in the heat exchanger system must bepurged before starting the first run. Refill thecoolant reservoir as needed. Repeat this processuntil all of the air has been purged from thesystem.

NOTE:

Starting the TGA 2050 CE

NOTE:



Installing the Hang-Down Wires

During installation, take care not to bend thehang-down wires or damage the hang-down loops.

1. Turn on the TGA instrument.

2. Press the FURNACE key to lower thefurnace.

3. Locate the sample hang-down wire in yourTGA Accessory Kit.

4. Hold the wire in your hand so that thedoubly bent top hook is pointing to the leftand the bottom hook is pointing to the right.

5. Carefully insert the bottom of the hang-down wire into the top of the furnace farenough so that you can insert the top of thewire into the hang-down tube withoutbending the wire (Figure 2.13 on the nextpage).

t CAUTION:


Figure 2.13Installing the SampleHang-Down Wire

6. Thread the hang-down wire up through thehang-down tube into the balance chamber,and hook the top of the wire over the top ofthe tube (see Figure 2.14 on the next page).

To make the hang-down loops easier to see, wesuggest sliding a piece of white paper into thebalance chamber behind each loop before you hookthe hang-down wire into it. (Do not forget toremove the paper when finished.) In addition, it isalso helpful to place a piece of paper over thefurnace opening to prevent the hang-down wirefrom falling into the furnace.

7. Grasp the top hook of the hang-down wirewith brass tweezers. Being careful to keepthe top hook pointing to the left, pass thedouble bend through the hang-down loop sothe wire is hanging from the loop.

8. Unscrew and remove the tare tube.


Hang-DownTube

NOTE:



Figure 2.14Installing the TareHang-Down Wire



9. Locate the tare hang-down wire in youraccessory kit.

10. Hold the wire in your hand so that thedoubly bent top hook is pointing to the leftand the bottom hook is pointing to the right.

11. Using brass tweezers, insert the tare hang-down wire into the balance chamber on thetare side and down through the hole abovethe tare tube connection, taking care not tobend the wire.

12. Being careful to keep the top hook pointingto the left, pass the double bend through thehang-down loop so the wire is hanging fromthe loop.

13. Select the sample pan you will use in yourexperiments and load one of the same sizeand type onto the tare hang-down wire.

14. Replace the tare tube and finger-tighten it tocompress the O-ring seal.

You are now ready to align the hang-downwires.



Aligning the Sample Hang-Down Wire

To avoid weight signal noise, the TGA instru-ment must be level so that the sample pan andhang-down wire hang inside the furnace andhang-down tube without touching them. Theangle at which the pan hangs is very sensitive toslight irregularities in benchtop surfaces, so it isimportant that you select a sturdy table or benchfor your TGA.

Once you have your TGA in a satisfactorylocation, adjust the top and bottom of the samplehang-down wire and level the instrument usingthe following procedures.

To align the top of the sample hang-down wire:

1. Place an empty sample pan on the sampleplatform.

2. Press the LOAD key on the instrumentkeypad. The TGA will automatically lowerthe furnace (if necessary), move the sampleplatform over to the furnace, and load thepan onto the balance.

If the pan will not automatically load, placethe pan manually (using brass tweezers) onthe sample hang-down wire and continuewith the procedure. Use the Sample Plat-form Adjust procedure (page 2-32) tocorrect loading after completing samplehang-down wire alignment.


3. Check to see whether the top end of thesample hang-down wire is hanging freelyand roughly centered within the top of thehang-down tube inside the balance chamber.

4. If the wire is not roughly centered inside thehang-down tube, turn the balance adjust-ment screw (Figure 2.16) with the 7/64-inchball driver until the wire is centered.

Turning the balance adjustment screwclockwise will move the wire toward theback; turning the screw counterclockwisewill move the wire toward the front.

Figure 2.16Location of BalanceAdjustment Screw

Top ofHang-DownTube

BalanceAdjustmentScrew

Hang-DownLoop andWire




To align the bottom of the hang-down wire:

1. Press the FURNACE key to raise thefurnace just to the bottom of the sample pan,and press STOP.

2. Check the alignment of the sample panwithin the furnace. It should hang freely,roughly centered, and should not be touch-ing the sides of the furnace or the hang-down tube (Figure 2.17).

3. If the sample pan is not centered and hang-ing freely within the furnace, level the TGAinstrument by adjusting the feet on thebottom. Turn the feet clockwise to lengthenor counterclockwise to shorten the legs.Continue adjusting until the pan hangscorrectly.


Figure 2.17Aligning the SamplePan in the Furnace

4. Press the FURNACE key to lower thefurnace.

5. Press the UNLOAD key to remove thesample pan from the furnace.

6. Replace the balance chamber faceplate andits 6 screws.

If you had to load the sample pan manuallyin order to align it in the furnace, you shouldnow adjust the sample platform using theprocedure described on the next page.

FurnaceHousing

Hang-DownTube

SamplePan




Adjusting the Sample Platform

If the sample hang-down wire fails to pick up asample pan during an automatic loading proce-dure, you will need to adjust the position of thesample platform, using the Sample PlatformAdjust procedure. This procedure is part of TGAinstrument control, see the online help anddocumentation for further information.


Shutting Downthe Instrument

Turning the system and its components on andoff frequently is discouraged. When you finishrunning an experiment on your TGA and wish touse the thermal analysis system for some othertask, leave the instrument on; it will not interferewith whatever else you wish to do.

If your system will not be used for longer thanfive days, we suggest that you turn it off. Topower down your instrument for any reason,simply press the POWER switch to the OFF (0)position.

Shutting Down the Instrument


CHAPTER 3: Running Experiments

Overview .................................................... 3-3

Before You Begin ............................... 3-4

Calibrating the TGA ................................... 3-5

Weight Calibration ............................... 3-5

Temperature Calibration ...................... 3-5

Running a TGA Experiment ....................... 3-6

Experimental Procedure ....................... 3-6

Preparing the Sample .......................... 3-7

Selecting Sampleand Tare Pans ................................ 3-7

Taring the Sample Pan ................... 3-8Automatic Tare ....................... 3-9Manual Tare ............................ 3-9

Loading the Sample ............................ 3-10

Setting Up an Experiment .................. 3-14

Setting Up Accessories ..................... 3-15

Using a Purge Gas ....................... 3-15Using the Air Cool Option .......... 3-18Using the Gas SwitchingAccessory .................................... 3-18

Starting an Experiment ....................... 3-20

Running Experiments


Stopping an Experiment ..................... 3-21

Unloading the Sample ................. 3-22

Use in an Oxygen-Free Atmosphere ......... 3-23

Purge Gas System............................... 3-23

Instrument Setup ................................ 3-24


OverviewAll of your TGA experiments will have thefollowing general outline. In some cases, not allof these steps will be performed.

Entering experiment information throughthe TA controller (sample and instrumentinformation)

Creating and loading the thermal method onthe controller

Attaching and setting up externalaccessories as required (e.g., purge gas, aircool, gas switching accessory)

Selecting and taring the sample pan Loading the sample Starting the experiment Unloading the sample at the end of the

experiment.

To obtain accurate results, follow procedurescarefully and check calibration periodically(once a month). Consult the online help anddocumentation for details on calibrating the TGAand conducting experiments.

Overview

Running Experiments


Before You Begin

Allow the TGA to warm up for at least 30 minutesbefore performiing an experiment.

Before you set up an experiment, ensure that theTGA and the controller have been installedproperly. Make sure you have:

Made all necessary cable connectionsbetween the TGA and the controller

Connected heat exchanger cable and waterlines

Connected all gas lines Powered on each unit Installed all appropriate options Configured the instrument online with the

controller Become familiar with controller operations Calibrated the instrument, if necessary.

NOTE:


Calibrating the TGAThe TGA 2050 CE requires two kinds ofcalibration: weight calibration and temperaturecalibration. Both of these calibrations should beperformed when you first install the instrumentand at least once a month thereafter. Consult theonline help and documentation for detailedinstructions on calibration.

Weight CalibrationTGA weight calibration uses standard referenceweights to calibrate the accuracy of the TGAbalance system. This calibration is conductedthrough the controller.

Temperature Calibration

Temperature calibration involves analyzing amaterial for its Curie Temperature, and compar-ing the observed value with the standard litera-ture value. The standard most often used isnickel with a curie temperature of 354.4°C(NIST Certificate for GM761). The CurieTemperature corresponds to the extrapolatedendpoint on the weight versus temperature curvegenerated utilizing a magnet.

Figure 3.1Curie TemperatureDetermination

Calibrating the TGA

Running Experiments


Running aTGA Experiment

Experimental Procedure

All of your TGA experiments will have thefollowing general outline.

Selecting and preparing a sample. Thisinvolves preparing a sample of theappropriate size, selecting the sample cup,and placing the sample in the cup.

Taring and loading the sample cup on thebalance.

Entering experimental information throughthe TA controller.

Creating and selecting the thermal methodon the controller.

Setting up any external accessories.

Starting the experiment.


Preparing the Sample

Selecting Sampleand Tare Pans

Three kinds of sample pans are available for theTGA 2050 CE: platinum, alumina ceramic, andaluminum. The platinum pans come in 50 and100 µL sizes, the ceramic pans come in 100,250, and 500 µL sizes, and the aluminum pansare 100 µL in size. The criteria for choosing asample pan are as follows:

For most experiments, platinum is thedesirable choice. It is easy to clean and doesnot react with most organics and polymers.Ceramic pans are more porous and aretherefore more easily contaminated. Thereare some conditions, however, in whichother types of pans are desirable, asexplained below.

Use ceramic pans for samples that mightamalgamate or react with platinum (e.g.,metals, corrosives, inorganics).

Use aluminum pans when disposability isdesired. Aluminum pans are meant for onetime use in experiments that do not goabove 600°C and for samples that do notreact with aluminum (e.g., corrosives, acidicmaterials, or anything that would alloy withaluminum).

If your sample will melt during the exper-iment, use a pan that is deep enough toprevent spilling (the deepest pan is the500 µL ceramic pan).

Running an Experiment

Running Experiments


The platinum and ceramic pan types are reus-able. To clean between experiments, use aBunsen burner or a propane torch, or run the panthrough a hot thermal program in the TGA toburn out any residue. Aluminum pans aredisposable, do not attempt to clean and reusethem.

Once you have selected the proper sample pan,remove the tare tube, and using brass tweezers,put the same type and size pan on the tare hook.

Whenever a different type of pan is selected, thebalance must be mechanically tared using step 1of the weight calibration.

Taring the Sample Pan

Taring the sample pan ensures that the weightmeasured by the balance reflects the weight ofthe sample only. You should tare the sample panbefore each experiment, even if you use thesame pan in consecutive experiments.

When you tare a pan, the TGA reads the weightof the empty pan and then stores the weight asan offset, which is subtracted from subsequentweight measurements. For optimum accuracy,the weight reading must be stable before it isaccepted as an offset. If you use the automatictare procedure, the TGA will determine whenthe weight reading is sufficiently stable; or youcan determine the acceptability of the weightreading by taring the system manually. Both tareprocedures are explained here.

NOTE:


Automatic Tare

Because the TGA 2050 CE has two weightranges, taring is done for both ranges. The tareweight is stored by the instrument for bothweight ranges.

1. Place the empty sample pan on the sampleplatform.

2. Press the TARE key on the instrumentkeypad or from the controller. The TGA willautomatically load the pan, raise the furnace(to protect the pan from air currents), weighthe pan, store the weight as the offset foreach weight range, and unload the pan.

Manual Tare

Manual tare operates in the weight rangeindicated, by storing the current reading as anoffset, and estimates the tare weight for the otherweight range (typically the 1-gm range). Theestimate is accurate if the TGA 2050 CE hasbeen tared or weight-calibrated recently.

1. Place the empty sample pan on the sampleplatform.

2. Press the LOAD key to load the pan onto thebalance.

3. Press the FURNACE key to close thefurnace, to protect the pan from air currents.

4. Observe the weight reading on thecontroller's Signal Display window screen(Signal A Weight).

5. Wait for the Signal A Weight to stabilize,and then choose Auto Zero to store thedisplayed weight as the offset.

6. Press the UNLOAD key to open the furnaceand unload the pan.


Running Experiments


Loading the Sample

After taring the sample pan, load the sample intothe TGA furnace as follows:

1. Place the sample in the sample pan, andposition the pan on the sample platform(Figure 3.2).

The wire on the bottom of the sample panshould align with the groove in the panhole,so that the sample pan can be picked up bythe sample hang-down wire.

Always use brass tweezers to handle the samplepans.

Manually loading the sample pan onto the hang-down wire may damage the balance mechanism.

Figure 3.2Sample PanReady to Load

NOTE:

t CAUTION:


2. Press the LOAD key. The TGA will auto-matically load the sample pan onto thebalance.

3. Position the thermocouple at the edge of thesample pan, rather than in the middle, forbest results (Figure 3.3).

The position of the thermocouple should be thesame as it was during temperature calibration.

Figure 3.3Adjusting the Thermocouple

NOTE:

SampleHook

Thermocoupleshould beabout 2mmfrom the pansurface.

Sample Pan

Thermocouple


Running Experiments


4. Press the FURNACE key to close thefurnace by moving it up around the sample,until it is fully closed as shown in Figure3.4.

Figure 3.4Furnace Closing


Figure 3.5Furnace inFully Closed Position


Running Experiments


Setting Up anExperiment

Once you have prepared the sample, the nextstep in your experiment is to enter the neededinformation in the TA controller. All of thecontroller functions described in this section areaccessed through the Instrument Control screen.Refer to the online help and documentation tolearn how to perform the following steps.

1. Select the Instrument.

2. Select the Instrument Mode.

3. Enter Sample Information.

4. Enter Instrument Information.

5. Create and Select Thermal Methods.

The first time you use your TGA you will needto create at least one thermal method to controlexperiments. Each method is made of severalsegments, or individual instructions (e.g.,Equilibrate, Ramp), that control the state of theinstrument.


Setting Up Accessories

If your experiment requires external accessories,ensure that they are turned on, and make anynecessary adjustments before you start yourexperiment. Make sure that the system canachieve the conditions of all segments in themethod.

This section describes how to use the followingaccessories with the TGA 2050 CE:

Air cool option Purge gas TA Instruments Gas Switching Accessory.

The TGA can also be used with other acces-sories, such as vacuum, FTIR, gas chromato-graphs, mass spectrometers, and evolved gasanalyzers. Consult the appropriate local instru-ment manufacturer for further information.

Using a Purge Gas

You can control the sample atmosphere duringTGA experiments by connecting a purge gas tothe system. Purge gas is distributed separatelyto two parts of the TGA: the furnace and thebalance chamber.

The balance purge maintains a positive pressurein the balance chamber to prevent decomposi-tion products from contaminating the sensitivebalance mechanism. The balance purge flowsfrom the balance chamber via two routes: down


Running Experiments


the hang-down tube and through an outlet in thebalance chamber to the right of the hang-downtube. It then exits across the sample pan alongwith the furnace purge.

The purge flow through the furnace is horizontalto the sample (Figure 3.6), permitting rapidremoval of decomposition products from thesample environment.

Figure 3.6Furnace Purge

You can choose nitrogen, oxygen, helium, air, orargon for your purge environment. Do not useany other gases in the TGA 2050 CE.

Do not use hydrogen or any other explosivegas in the TGA 2050 CE furnace. Oxygen maybe used. However, the furnace must be keptclean of volatile hydrocarbons to preventcombustion.

Do not use any liquid in the purge lines.

!WARNING

!WARNING


Purge gas can be obtained from a pressurizedcylinder or an in-house supply source. Gassupplied from an in-house source should bepassed through a sieve dryer to remove any traceof moisture before in enters the TGA.

It is important to maintain the proper ratio offlow rates between the balance chamber and thefurnace housing. Having the separate balancechamber purge prevents decomposition gasesfrom entering the balance chamber. The recom-mended setting for the purge rate is 100 cc perminute or less. The flow distribution should be10 percent to the balance chamber and 90percent to the furnace.

To maintain this flow distribution, you will needto connect a flowmeter to each of the purgefittings on the back of the TGA instrument. Setthe purge gas flow rates by adjusting thesemeters. The PURGE port goes to the TGAfurnace, and the BALANCE PURGE goes to thebalance chamber.

Before you start the purge gas, make sure thatthe desired gas is connected to the purge ports,that all lines are clear, and that your supply ofpurge gas is sufficient for the experiment.Always maintain constant purge flow rates anddistribution throughout your experiment;changing the purge during an experiment canaffect the data.


Running Experiments


Using the AirCool Option

You can program the system to air cool thefurnace automatically at the end of the experi-ment by selecting this option from the TAcontroller. After the air cool is activated, it willcontinue to run for the desired time.

Before you start an experiment that uses the aircool option, ensure that the supply valve fromthe air source is open and that the pressure isregulated to between 25 and 120 psig. Nitrogencan also be used as a cooling gas.

Air Cool can be used with the furnace closed.However, if the temperature is above 500°C, thefurnace will cool naturally until it is 500°C or less,then Air Cool will begin.

Using the GasSwitching Accessory

You can use the Gas Switching Accessory toturn the purge gas on and off or to switchbetween two different purge gases during a TGAexperiment. Before starting an experiment thatuses the Gas Switching Accessory, make sure itspower switch is on, and make sure the necessarygas sources are properly connected.

The Gas Switching Accessory can be controlledby the Gas segment in the method (see the onlinehelp and documentation for further information).or by the Gas control option.

NOTE:


Connect the Gas Switching Accessory to thepurge port only, when switching between gasesduring an experiment. Attach the inert gas toGAS 1 and the other gas to GAS 2.

Consult your Gas Switching Accessoryoperators manual for further instructions.


Running Experiments


Starting an Experiment

You can begin the experiment using either theSTART key on the TGA instrument keypad orselect Start on the controller. When you start,the system automatically begins the set-upprocedures. It loads the sample pan and closesthe furnace, if necessary, and then begins theselected method and data collection starts.

If you wish to start collecting data duringinstrument setup, you can use the forced startfeature. This is most useful for samples thatloose a significant amount of weight during theset-up period (i.e., samples with volatile sol-vents). When a forced start is initiated, thecurrent sample weight is stored as the initialweight, data collection is started immediately,and the instrument status changes from Set Upto Started. The method begins when thenormal set-up procedures are completed.

Once the experiment is started, operations arebest performed at the controller keyboard. TheTGA 2050 CE is very sensitive to motion and mightpick up the vibration caused by pressing a key onthe instrument keypad.

Forced Start

Press the START key on the instrument keypadwhile the controller status line displays SetUp.

NOTE:


Stopping an Experiment

If for some reason you need to discontinue theexperiment, you can stop it at any point by usingeither the STOP key on the TGA instrumentkeypad or Stop on the controller screen. Anotherfunction that stops the experiment is Reject onthe controller. However, the Reject functiondiscards all of the data from the experiment; theStop function saves any data collected up to thepoint at which the experiment was stopped.

The Heat Exchanger will continue to run until it ismanually turned off.

The REJECT function discards all experimentdata.


NOTE:

t CAUTION:

Running Experiments


Unloading the Sample

If you select the Furnace Open and Unloadmethod-end option on the controller, the TGAwill automatically unload the sample at the endof the run. If you need to unload the samplemanually, wait until the run and all method-endoperations are complete, and then press theUNLOAD key. The sample pan may not line upwith the sample platform groove at method end.


Use in anOxygen-FreeAtmosphere

A few extra precautions are necessary to ensurean oxygen-free environment.

Purge Gas System

Use a high purity, inert gas of grade 5 orbetter. It may be necessary to use anoxygen trap in-line, depending on the puritygrade.

Choose a 2-stage regulator of diaphragmconstruction for high purity applications.

Use copper or stainless steel tubing fromthe gas regulator, to the flowmeters, and tothe TGA purge inlet ports.

Allow the TGA to prepurge (under closedconditions) for at least 30 minutes after firstturning on your purge gas. Increase thestandard purge rate during this time.

100 cc/minute flow into the balancechamber and 100 cc/minute into thefurnace.

Use in an Oxygen-Free Atmosphere

Running Experiments


Instrument Setup

Readjust your flowmeter(s) for standardoperating flow rates.

10 cc/minute flow into balance chamber and90 cc/minute into the furnace.

Tare sample pan (as needed).

Load sample and close system

Purge 20 minutes, if possible, beforestarting a run.

When run is complete, allow the furnace tocool in the closed position. This can bedone by changing the method-endconditions to leave the furnace closed atmethod end.

When using air or oxygen during anexperiment, introduce new gas throughfurnace purge port only and switch back tothe inert gas before cooling down.

When the TGA is idle, leave the system closed andcontinue purging with the inert gas.

NOTE:


CHAPTER 4: Technical Reference

Description of the TGA 2050 CE .............. 4-3

Components .......................................... 4-5

Balance .......................................... 4-6Sample Loading Assembly ............ 4-8Furnace .......................................... 4-9Cabinet ......................................... 4-11Heat Exchanger ............................ 4-13

Theory of Operation ................................. 4-14

Status Codes ............................................ 4-15

Technical Reference

TA INSTRUMENTS TGA 2050 CE4–2


Description ofthe TGA 2050 CE

The TGA 2050 CE operates on a null balanceprinciple. Physically attached to a taut-bandmeter movement, the balance arm is maintainedin a horizontal reference position by an opticallyactuated servo loop. When the balance is in anull position, a flag located on top of the balancearm blocks an equal amount of light to each ofthe photodiodes (the light is supplied by aconstant current infrared LED). As sampleweight is lost or gained, the beam becomesunbalanced, causing an unequal amount of lightto strike the photodiodes. The unbalancedsignal, called the error signal, is acted upon bythe control circuitry and reduced to zero, ornulled. This is accomplished by an increase ordecrease in the current to the meter movement,causing it to rotate back to its original position(null position). The change in current necessaryto accomplish this task is directly proportional tothe change in mass of the sample. This currentis converted to the weight signal.

The TGA 2050 CE has two weight ranges: 1 gmand 100 mg. Both ranges are continuous overtheir weight loss operating range, which meansthat the entire weight loss range can be viewedwithout any loss of information. The weight lossoperating ranges are:

• 1 gm to 0 µg for the 1 gm range• 100 mg to 0 µg for the 100 mg range.

Negative weight (tare imbalance) is limited to150 mg in the 1 gm range, and to 15 mg in the100 mg range. Range control is automatic.

Description of the TGA 2050 CE

Technical Reference


During normal operation of the TGA, the samplemay evolve gases. To prevent back diffusion ofthese liberated gases to the balance chamber, thebalance chamber is purged with an inert gas (10cc/min). An inert gas must be used to preventcontamination or corrosion of the balance.

Heating rate and sample temperature are mea-sured by the thermocouple located above thesample. This enables the controller to programand maintain the sample environment at yourselected rate.


Components

The TGA 2050 CE has five major components,illustrated in Figure 4.1: the balance, the sampleloading assembly, the furnace, the cabinet, andthe heat exchanger.

Figure 4.1TGA 2050 CE Components

The balance, the most important part of theTGA system, provides precise measurement ofthe sample weight. The sample loading assem-bly automatically loads and unloads samplesfrom the TGA balance. The furnace controls thesample atmosphere and temperature. Thecabinet contains the system electronics andmechanics. The heat exchanger dissipates heatfrom the furnace.


Thermocouple

Furnace

BalanceChamber

PowerLight

ReadyLight

SampleLoadingAssembly

Keypad

HeatExchanger

Cabinet

Technical Reference


Balance

The TGA balance assembly (shown in Figure4.2 below) consists of the balance meter move-ment, the balance arm, the balance arm sensor,the hang-down wire assemblies, the sample pan,and the tare pan.

Figure 4.2TGA Balance Assembly

The balance meter movement is a taut-bandmeter movement to which the balance arm isattached.

The balance arm is a rhombic piece of alumi-num attached to the meter movement. It is in anull balance system. A hang-down loop isattached to each end to hold the hang-downwires.

Balance ArmSensor

Balance MeterMovement

Tare Pan

BalanceArm

SamplePan

Hang-DownWireAssembly


The balance arm sensor is a printed circuitboard assembly that detects the null position ofthe meter movement. The balance beam sensoris mounted above the balance arm. It is used inconjunction with the analog circuitry to maintaina null position.

The TGA has two hang-down wire assemblies:one for the tare pan and one for the sample pan.Each assembly consists of a hang-down wire andloop. The hang-down wire has hooks at each endand connects the pan to the loop. The loop haseyelets at each end; it is used to connect thehang-down wire to the balance arm. The longerhang-down wire (4 inches) is for the sample pan.

Sample pans are available in platinum in 50 and100 µL sizes, alumina ceramic in 100, 250, and500 µL sizes, and aluminum in 100 µL size. Allpans are 0.4 inch in diameter.

The tare pan holds the counterbalance weightthat mechanically subtracts out the weight of thesample pan.


Technical Reference


Sample Loading Assembly

The sample loading assembly (Figure 4.3) is aplatform that pivots the sample pan to thefurnace area, where the pan engages the hang-down wire from the balance assembly. It alsopivots the platform away from the furnace areafor easy sample loading and unloading.

Figure 4.3Sample Loading Assembly


Furnace

The TGA furnace consists of a quartz glasssample tube surrounded by an electric resistanceheater, both of which are contained within awater-cooled furnace housing. The housing ismounted to a furnace base that raises andlowers the furnace for sample loading andunloading. See Figure 4.4.

Figure 4.4Furnace

The sample tube has a purge gas inlet thatpasses through the right side of the furnacehousing. A fitting on the left side of the housingallows connection of a transfer line to carryexhaust gas to a spectrometer such as a FTIR.Because the heater is external to the sampletube, evolved gases from sample decompositionwithin the sample tube do not come in contactwith the resistance elements or the furnaceceramic refractory.


Technical Reference


Cooling air enters through the furnace base andpasses upward between the outside of thesample tube and the inside of the furnace,completely separating the cooling air from thesample and the sample zone.

The furnace is a resistance heater wound onalumina ceramic, which allows sample zonetemperatures as high as 1000°C with heatingrates up to 50°C/min.

A Platinel II* thermocouple is positioned in thefurnace, just above the sample pan, where itmonitors the sample environment temperature.

The furnace base moves the furnace assemblyup around the sample pan to the closed position,or down away from the sample pan to the openposition.

* Platinel II is a registered trademark ofEngelhard Industries.



CabinetThe TGA cabinet (Figure 4.5) consists of thecabinet housing, the keypad, the electronicscompartment, the purge and cooling gas fittings,and the rear panel.

Figure 4.5TGA CabinetComponents

The TGA cabinet housing consists of a baseand a rear cover. The base is a single piece ofheavy-weight aluminum, designed to provide astable platform for the TGA instrument parts.

The TGA instrument keypad is described inChapter 1.

The electronics compartment contains theelectronics that control the instrument functions.

Two purge fittings are located on the back ofthe instrument, one for the balance chamber andone for the furnace housing.

Technical Reference


The cooling gas fitting is located on the leftside of the instrument back and is for furnacecool-down air.

The rear panel (Figure 4.6) has the signal andpower connections for the instrument; the fuses;the ready light; the POWER switch; the addressswitch; the purge, gas, serial port, and GPIBconnections; and the Reset button.

Figure 4.6Rear Panel


Heat Exchanger

The heat exchanger (Figure 4.7) consists of afan, a radiator, a water reservoir, and a pump.

The fan blows cool air through the radiator.

The radiator exchanges heat between the waterand air.

The water reservoir holds additional water thatmay be required by the system.

The pump circulates the water through thesystem.

Figure 4.7Heat Exchanger


Radiator

Water ReserviorBottle

TemperatureSwitch

Flow Swtich

Fan

Pump

Technical Reference


Theory ofOperation

Thermogravimetric analysis (TGA) is a thermalanalysis technique for measuring the amount andrate of change in sample mass as a function oftemperature and time. It is used to characterizeany material that exhibits weight loss or phasechanges as a result of decomposition, dehydra-tion, and oxidation. Two modes are commonlyused for investigating thermal stability behaviorin controlled atmospheres: (1) dynamic, inwhich the temperature is increased at a linearrate, and (2) isothermal, in which the tempera-ture is kept constant.


Status Codes

Status CodesStatus codes are continuously displayed at the topof the controller screen.

Table 4.1Method Status Codes

Code Meaning

Air Cool The furnace air cool linehas been opened to coolthe furnace.

Calib The TGA Calibrationprogram is running.

Closing The furnace assembly isclosing.

Cold The instrument heatercannot supply heat fastenough to keep up withthe thermal program. Thismay be caused by a largeballistic jump in theprogram, a faulty heater,or a faulty control thermo-couple signal.

Complete The thermal method hasfinished.

(table continued)

Technical Reference


Table 4.1Method Status Codes(continued)

Code Meaning

Cooling The heater is cooling, asspecified by a Rampsegment.

Ending The method is completeand the furnace is coolinguntil it can Air Cool oropen and unload.

Equilb The temperature is beingequilibrated to the desiredset point.

Heating The heater temperature isincreasing, as specified bya Ramp segment.

Holding Thermal experimentconditions are holding;the program is suspended.Select Resume to con-tinue the run.

Hot The temperature isbeyond the set point, andthe instrument cannotremove heat fast enoughto follow the thermalprogram. This is usuallycaused by a large ballisticjump to a lower tempera-ture.

(table continued)


Status Codes

Table 4.1(continued)

Code Meaning

Initial The temperature is beingequilibrated to the desiredset point. When thetemperature has reachedequilibrium, the statuswill change to “Ready.”

Iso The thermal program isholding the currenttemperature isothermally.

Jumping The heater is jumpingballistically to the setpoint temperature.

Load The TGA is loading asample pan onto thebalance.

No Power No power is being appliedto the heater. Check theheater fuse.

Opening The furnace assembly isopening.

Ready The system has equili-brated at the initialtemperature and is ready to begin the nextsegment. Use the Startfunction to continue themethod.

(table continued)

Technical Reference


Table 4.1Method Status Codes(continued)

Code Meaning

Reject The experiment has beenterminated and the dataerased.

Repeat The method is executing arepeat loop that does notinvolve temperaturecontrol segments.

Set Up The system is loading thesample, closing thefurnace, and letting theweight stabilize beforebeginning the first seg-ment.

Stand by The method and method-end operations are com-plete.

Started The TGA is still settingup to start the experiment(see Set Up above), butthe initial weight has beenmeasured and data col-lection has begun. Thethermal method willstart when the normalsetup process has beencompleted.

(table continued)


Status Codes

Table 4.1(continued)

Code Meaning

Tare The TGA is measuringthe weight differencebetween an empty samplepan and the tare pan. Themeasured weight is usedas an offset so that thedisplayed weight valueindicates the weight of thesample only.

Temp The heater is in stand-bymode, and the experimenthas been terminated.

Unload The TGA is unloading asample from the balance.

Technical Reference



CHAPTER 5: Maintenance andDiagnostics

Overview .....................................................5-3

Routine Maintenance ..................................5-4

Inspection .............................................5-4

Cleaning the Instrument Keypad ..........5-4

Cleaning the QuartzFurnace Tube ........................................5-4

Heat Exchanger ....................................5-7

Maintaining HeatExchanger Coolant ........................5-7Draining and Refilling theWater Reservoir .............................5-7

Replacing the Thermocouple ....................5-10

Diagnosing Power Problems .....................5-12

Fuses ...................................................5-12

Power Failures ....................................5-13

TGA 2050 CE Test Functions ..................5-14

The Confidence Test ..........................5-14

Replacement Parts ....................................5-16

TA INSTRUMENTS TGA 2050 CE

Maintenance & Diagnostics

5–2


OverviewThe procedures described in this section are thecustomer’s responsibility. Any further mainte-nance should be performed by a representativeof TA Instruments or other qualified servicepersonnel.

Because of the high voltages in this instru-ment, untrained personnel must not at-tempt to test or repair any electricalcircuits.....

!WARNING

Overview



5–4

Routine Maintenance

InspectionExamine the instrument periodically to keep itfree of dust, debris, and moisture. Keep thefurnace area clean. Any sample spillage ofresidue should be removed before the nextexperiment.

Cleaning theInstrument Keypad

You can clean the TGA instrument keypad asoften as you like. The keypad is covered with asilk-screen Mylar* overlay that is reasonablywater resistant but not waterproof or resistant tostrong solvents or abrasives.

A household liquid glass cleaner and papertowel are best for cleaning the instrumentkeypad. Wet the towel, not the keypad, with theglass cleaner, and then wipe off the keypad.

Cleaning theQuartz Furnace Tube

If the TGA is used to evaluate materials usingan oxygen purge, the furnace must be cleanedroutinely to prevent build-up of volatile hydro-carbon residues that could combust.

Do not touch the furnace sample tube withyour bare fingers. Skin oils may causedevitrification of the quartz glass, resultingin severely reduced sample tube life. Do

!WARNING

!WARNING


not insert metallic instruments inside thesample tube to scrape or chip contaminantsfrom the sample tube as breakage may result.

*Mylar is a registered trademark of the DuPontCompany.

To clean the furnace quartz sample tube, use thefollowing procedure:

Do not disturb the hang-down wire andfurnace thermocouple located directlyabove the furnace when cleaning the fur-nace, as damage may result.

1. Press the FURNACE key to open thefurnace completely.

2. Turn instrument power off.

3. Be sure the furnace is cool. Remove anysample pans.

4. Remove the rubber cap located on theunderside of the furnace base.

5. Place a small cup under the furnace tube.Rinse the furnace tube using a solvent (suchas alcohol) to remove debris. The solventwill drain out of the bottom of the tube intothe cup.

6. Using a soft bristle brush (we recommend aflexible bottle brush), gently slide the brushup and down to clean out the inside of thefurnace tube, allowing the handle to bendfreely (see Figure 5.1 on the next page).

Routine Maintenance

!WARNING

!WARNING(cont'd)



5–6

Figure 5.1Cleaning theInside of theFurnace Tube

7. Rinse the furnace tube with the solventagain.

8. Replace the rubber cap on the quartz tubestem when you have completed the cleaningprocedure.

9. Purge system for one hour with nitrogen.

10. Heat the furnace to 900°C to remove anyremaining solvent.


Heat Exchanger

The heat exchanger does not require any mainte-nance other than to maintain the level andquality of the liquid coolant. If the level dropstoo low, or the coolant becomes contaminated,this could result in problems with your instru-ment.

Do not put any liquid other than distilledwater and TA Conditioner in the heatexchanger reservoir.

Maintaining HeatExchanger Coolant

You should check the level and condition of theheat exchanger coolant periodically. We recom-mend routine checks every three to six months,depending on use of the instrument.

Add distilled water to the reservoir, if necessary,to keep the reservoir at least 2/3 full. If algaegrowth is visible, drain the reservoir bottle, refillit with distilled water, and add TA InstrumentsTGA Conditioner, as described in the nextsection.

Draining and Refillingthe Water Reservoir

Drain and refill the heat exchanger waterreservoir as follows:

1. Turn off the heat exchanger POWER switchand disconnect the power cable and waterlines from the heat exchanger (see Chapter 2for instructions).

Routine Maintenance

!WARNING



5–8

2. Unscrew and remove the water reservoircap.

3. Drain the coolant and flush out the systemas follows:

a. Lift the heat exchanger and dump outthe contents of the water reservoirbottle.

b. Fill the bottle to 2/3 full with distilledwater only and replace the cap.

c. Reconnect the heat exchanger powercord and water lines to the heat ex-changer.

d. Turn on the heat exchanger POWERswitch.

e. Allow the water to circulate for severalminutes.

f. Turn off the pump and check the clarityof the water in the reservoir bottle.

g. If the water clarity is still unacceptable,repeat steps 1 through 3.

h. Continue repeating this procedure untilyou are satisfied with the clarity of thewater in the bottle after it has circulated.

4. Dispose of the water and fill the bottlewith TGA Conditioner (PN 952377.901)and fresh distilled water as directed inChapter 2.

5. Turn on the pump again and circulate thewater until the air bubbles disappear fromthe water lines.

6. Replace and tighten the water reservoir cap.


Replacing the Thermocouple

1. Unload the sample pan and open theinstrument’s furnace.

2. Using the ball driver supplied in your TGAaccessory kit, loosen and remove the sixscrews securing the balance chamberfaceplate to the instrument.

3. Take off the faceplate.

4. Push the thermocouple up from the bottom,to feed it back into the balance chamber(Figure 5.2).

Figure 5.2Removing theThermocouple

5. Unplug the thermocouple from its connectorand remove the thermocouple from thebalance chamber.

6. Plug the new thermocouple carefully intothe connector.

Routine Maintenance



5–10

7. Thread the new thermocouple down throughthe hole next to the hang-down tube.

8. Thread the end of the thermocouple justthrough the ceramic disk at the end of thehang-down tube.

9. Load a sample pan to make sure that the endof the thermocouple does not touch it(Figure 5.3).

Figure 5.3Checking Positionof Thermocouple

10. Make sure that the hang-down wire does nottouch the top of the thermocouple inside thebalance chamber.

11. Replace the balance chamber faceplate andscrews.

12. Repeat temperature calibration.


Diagnosing Power Problems

Fuses

The TGA contains internal fuses tha

tga 2050 ce operator's manual · 2015. 9. 7. · ta instruments tga 2050 ce i tga 2050 ce...

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