Valco Instruments Co. Inc. TCD User manual

Valco Instruments Co. Inc.
tcd2.p65
Rev 4/12
Printed in USA
Microvolume Thermal
Conductivity Detector
Instruction Manual
Valco Instruments Co. Inc.
800 · 367 · 8424 sales
713 · 688 · 9345 tech
713 · 688 · 8106 fax
[email protected]
VICI AG International
Schenkon, Switzerland
Int + 41 · 41 · 925 · 6200 phone
Int + 41 · 41 · 925 · 6201 fax
[email protected]
North America, South America, and Australia/Oceania contact: Europe, Asia, and Africa contact:

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Table of Contents
Introduction
Descriptionand OperatingPrinciple ............................................................... 1
SafetyNotesand Information ........................................................................ 2
Components of the Detector System ............................................................. 3
Descriptionof Controls andConnectors ......................................................... 4
SystemRequirements
Components Not Included with the Detector System ..................................... 7
System Purity................................................................................................ 7
RecommendedCarrier GasPurifiers .............................................................. 7
CarrierGas Selection..................................................................................... 7
GCColumn Selection..................................................................................... 8
Installation
GeneralPrecautions ...................................................................................... 9
MountingtheDetector on theGC ................................................................... 9
GasConnections ..........................................................................................10
ColumnConnection.......................................................................................12
ElectricalConnections ..................................................................................13
InitialPower-Up .............................................................................................15
Troubleshooting
TroubleshootingChart ...................................................................................17
HeaterFaultDetermination............................................................................17
DetectorFaultDetermination.........................................................................18
Maintenance
BakeOut Procedure .....................................................................................19
Disassemblyand Cleaning............................................................................19
Warranty .............................................................................................................20
DetectorPerformanceLog ...................................................................................21

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1
Introduction
DescriptionandOperatingPrinciple
TheThermalConductivity Detector (TCD)hasbeen oneofthe most popular
GC detectors since the 1950’s, second perhaps only to the Flame Ionization
Detector (FID). The principal of operation is based on the relative change in
the thermal conductivity of the gas passing across the detector filament as
components elute from the column. Heat is lost continuously by the filament
through the carrier gas to the cell wall of the detector. By measuring the
amountofcurrent required tomaintaina constant filament temperatureas
gases of varying thermal conductivities cross the filament, a chromato-
graphic signal is produced. This process is nondestructive of the sample and
isconcentration dependent.
TheValco MicrovolumeTCD is unique in its implementation. Since changes
in conductivity are measured only by the change in current required to keep
the filament at a constant temperature, each of the two filaments can be
operatedindependently without referencingthese changestoa matched
filament with reference gas. This constant temperature provides longer
filament life and safeguards it from the extremely high temperatures and
oxidation which can occur with high concentrations of oxidative or corrosive
components. Optionalsignal referencing isprovidedto minimizebackground
variablessuch as columnbleed andtemperatureprogramming.
Figure 1: Unique dual filamentdesign
Cell volume has been minimized to accommodate capillary column
chromatography and optimize the sensitivity of the detector at low flow
rates. (Carrier flow rates of 1 - 10 mL/min are recommended for best sensi-
tivity.) Thermal stability is maintained in the detector cell to within 0.010°C
drift, giving the detector a stable, noise-free signal.
The ModelTCD2 is a stand-alone system which can be easily added to
any chromatograph. It consists of a detector and a control module which
incorporates the electrometer andtemperaturecontrols. Thedetector cell
includestwo separate filaments,capableof independentorreferenced
(differential)operation. Outputsignal is providedas0-1 and 0-10 volt
attenuatedforchartrecordersand 0-1 and 0-10voltsunattenuatedfor
integrators and data systems.
FILAMENT
AFILAMENT B
A
FLOW
INLET
B
FLOW
INLET
OUTLET OUTLET

2
Safety Notes and Information
Symbols HOTSURFACE
The surface of the detector body may be hot while in
operation (possibly in excess of 250°C). Observe caution.
ATTENTION
Refertothe manual.
PROTECTIVE EARTH
Thisinternalconnection provides protectionagainst electric
shock from mains voltages and should not be removed.
InstallationCategory
Thisequipment has beendesigned for installationcategory (overvoltage
category) II, pollution degree 2. It has been approved for use only in heavy
industrial environments and may not be used in the residential, commercial,
orlight-industrial environment.
Safety
This instrument has been designed and tested in accordance with the
product safety standard, EN61010. It has left the factory in a safe
condition. This instruction manual contains important information and
warnings which must be followed by the user to insure safe operation and to
retain the instrument in a safe condition. The case, chassis, and measuring
terminals are connected to the protective earth contact of the mains inlet.
Theinstrument operates witha three-conductor powercord having apro-
tective earthing conductor and a plug with an earthing contact. The mains
(line) plug shall only be inserted in a socket outlet provided with a protective
earth contact. The protective action must not be negated by the use of an
extension cord without a protective conductor. Use only with an approved
mains supply cord having a rating of 2A, 250V, or greater. Do not use this
equipmentina mannernotspecified herein.
Maintenance
The exterior of the instrument should be cleaned regularly with a dusting
brush.If necessary, the casing can be cleaned with a moistened cloth
(99% water + 1% mild detergent). Spirit or petroleum ether can be used
to remove greasy dirt. Any other cleaning agents can attack the plastic
andpainted surfaces.
Under no circumstances should the cleaning fluid get into the instrument.
Petroleum ether is flammable, and care should be taken in its use.
The detector must be returned to the factory when filament replacement is
required. CallVICITech Support for return authorization.
Introduction

3
Components of the Detector Systems
Components of the detector system are listed in Tables 1 and 2. Check the
contents of the packages to verify that everything is present. Contact the
factory if anything is missing or damaged. (NOTE: damaged shipments
must remain with the original packaging for freight company inspection.)
Introduction
Description Quantity Product number
Detector cell, Nickel-Iron filament 1 TCD2-NIFED
Controller unit with power cord 1 TCD2-C
Includes: Cable, output 2 I-24010
1/16' zero dead volume union 2 ZU1C
Fused silica adapter for 0.53 mm ID x 0.8 mm OD capillary column 2 FS1R.8
1/16" zero dead volume nut 2 ZN1
1/16" zero dead volume ferrule 2 ZF1
Table 1: Components of the TCD2-NIFE system
Description Quantity Product number
Detector cell, Tungsten-Rhenium filament 1 TCD2-WRE
Controller unit with power cord 1 TCD2-C
Includes: Cable, output 2 I-24010
1/16' zero dead volume union 2 ZU1C
Fused silica adapter for 0.53 mm ID x 0.8 mm OD capillary column 2 FS1R.8
1/16" zero dead volume nut 2 ZN1
1/16" zero dead volume ferrule 2 ZF1
Table 2: Components of the TCD2-WRE system
Specifications
Mains(line): 115/230V~50/60 Hz,175VA
Fuse: 2 A, time-delay, 5 x 20 mm
Pressure: 6.9 kPa (1 psi) operating, 6.9 MPa (1000 psi) max.
working
Maximumtemperature 300°C
Heaterpower: 60 W max., 48V, PWM
Outputimpedance: 100 Ω

4
Description of Controls and Connectors
Controls and connectors are indicated in Figures 2 and 4.
MAINS switch(rear panel)
Controls mains (line) voltage to the controller unit. When this switch is
on ( | ), the unit is operational except for the detector filaments (see next
paragraph)and thedetectorheater willoperate ifconnected.
FILAMENT switchandindicator
Controls power to the detector filaments; when the switch is on, current
passes through the filaments. The indicator will light even if the detector
is not connected to the controller.
DETECTORTEMPERATURE control andindicator
Sets the temperature (°C) of the detector heater block. The indicator is
steadily on when maximum power is being applied to the heater, steadily
off when no power is applied, and regularly blinking on/off when the set
temperaturehas beenestablished.
Note that due to the fail-safe mechanism designed into the temperature
controller, the heater will not operate if mains power is applied before the
heater is connected or if the detector is too cold (< 0°C). If the heater is
disconnected with mains on, the unit must first be turned off to restore
control of the heater; if the unit is operated in a very cold environment,
thedetectorshould first begently warmed without powerapplied.
The fail-safe mechanism will also act under any condition resulting from loss
ofcontrol( e.g. ,over-heating,RTD failure, etc.). Ifproperprocedures have
been followed and the controller will not heat the detector, there is cause
to suspect that the fail-safe mechanism has been activated. Consult the
factoryoran authorized representative. Notethat the maximum temperature
for operationof theTCD2is 300°C.
FILAMENTTEMPERATURE switch
Separate 10-turn knobs control Filaments A and B.The value displayed
corresponds to temperatures indicated in Figure 3 for nickel/iron filaments.
COARSE ZERO control
Oncefilamenttemperature hasbeenapplied, the CoarseZero knob makes
coarse adjustments of the zeroing voltage supplied for establishing the
baseline zero on both the strip chart output and the integrator outputs.
FINE ZERO control
Once coarse adjustments have been made, the Fine Zero control is used to
make fine adjustments in the output signals.
ATTENUATION control
The Attenuation control determines the attenuation of the signal for the chart
output.
RECORDERswitch
The Recorder switch selects which signal is directed to the chart output.
The choices are A, B, or A - B (or A minus B, which is conventional
differentialoperation with theB channel representingthe reference.)
The selected output signal is displayed in the LCD display.
Introduction

5
Introduction
Figure 2: Front panel controls
Figure 3: Actual filament temperature vs. filament temperature knob settings
ACTUAL TEMPERATURE IN °C
FILAMENT TEMPERATURE KNOB SETTING
012345678910
0
50
100
150
200
250
300
350
400

6
MAINS POWER connector
For connection to 115/230VAC source.
CHART OUTPUT connector
Normally connected to a strip chart recorder. This output has an attenuated
range of 0-1 volt and 0 - 10 volts, with the signal scaled by the attenuation
factor set on the front panel. The output also has an internal signal reference
(-) at zero volts. For best noise performance, the shield (earth) and signal
reference(-)should notbeconnected together.
UNATTENUATEDOUTPUT connector
Normally connected to a data acquisition system or other recording means.
For convenience, full-scale 0 - 1V and 0 - 10V outputs are provided, with an
internal signal reference (-) at zero volts. For best noise performance, the
shield(earth)andsignal reference(-)shouldnot beconnected together.
DETECTORconnector
For connection to the detector control and heating system.
NOTE:These terminals are for connection only to
equipment having no accessible live parts.
Introduction
Figure 4:Rear panelconnectors
CHART AB A-B
OUTPUTS
DETECTOR
SERIAL NO.MODEL NO.
Valco Instruments Co. Inc.
MAINS SWITCHMAINS POWER
CONNECTOR
DETECTOR
CONNECTOR
CHART OUTPUT
CONNECTOR
UNATTENUATED
OUTPUT
CONNECTORS
MODEL TCD2-C
115/230 175VA MAX.
T2.0A
250V
MAINS
Valco Instruments Co. Inc.
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