VICI TCD2 User Manual
Valco Instruments Co. Inc.
Microvolume Thermal
Conductivity Detector
Instruction Manual
North America, South America, and Australia/Oceania contact: Europe, Asia, and Africa contact:
Valco Instruments Co. Inc.
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688
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9345 tech
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8106 fax
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valco@vici.com
VICI AG International
Schenkon, Switzerland
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tcd2.p65
Rev 4/12
Printed in USA
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Table of Contents
Introduction
Description and Operating Principle ............................................................... 1
Safety Notes and Information ........................................................................ 2
Components of the Detector System ............................................................. 3
Description of Controls and Connectors ......................................................... 4
System Requirements
Components Not Included with the Detector System ..................................... 7
System Purity................................................................................................ 7
Recommended Carrier Gas Purifiers .............................................................. 7
Carrier Gas Selection..................................................................................... 7
GC Column Selection..................................................................................... 8
Installation
General Precautions ...................................................................................... 9
Mounting the Detector on the GC................................................................... 9
Gas Connections ..........................................................................................1 0
Column Connection.......................................................................................1 2
Electrical Connections ..................................................................................1 3
Initial Pow er-Up .............................................................................................1 5
T roubleshooting
T roubleshooting Chart ...................................................................................1 7
Heater Fault Determination............................................................................1 7
Detector Fault Determination.........................................................................1 8
Maintenance
Bake Out Procedure .....................................................................................19
Disassembly and Cleaning............................................................................19
Warranty .............................................................................................................20
Detector Perf ormance Log ...................................................................................2 1
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Introduction
Description and Operating Principle
1
The Thermal Conductivity Detector (TCD) has been one of the 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
amount of current required to maintain a constant filament temperature as
gases of varying thermal conductivities cross the filament, a chromatographic signal is produced. This process is nondestructive of the sample and
is concentration dependent.
The Valco Microvolume TCD 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
operated independently without referencing these changes to a 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. Optional signal referencing is provided to minimize background
variables such as column bleed and temperature programming.
OUTLET OUTLET
FILAMENT
A
A
FLOW
INLET
FILAMENT
B
B
FLOW
INLET
Figure 1: Unique dual filament design
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 sensitivity.) Thermal stability is maintained in the detector cell to within 0.010°C
drift, giving the detector a stable, noise-free signal.
The Model TCD2 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 and temperature controls. The detector cell
includes two separate filaments, capable of independent or referenced
(differential) operation. Output signal is provided as 0-1 and 0-10 volt
attenuated for chart recorders and 0-1 and 0-10 volts unattenuated for
integrators and data systems.
Introduction
2
Safety Notes and Information
Symbols
HOT SURF AC E
The surface of the detector body may be hot while in
operation (possibly in excess of 250°C). Observe caution.
A TTENTION
Refer to the manual.
PROTECTIVE EARTH
This internal connection provides protection against electric
shock from mains voltages and should not be removed.
Installation Category
This equipment has been designed for installation category (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,
or light-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.
The instrument operates with a three-conductor power cord having a protective 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 appro ve d
mains supply cord having a rating of 2A, 250V, or greater. Do not use this
equipment in a manner not specified 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
and painted surfaces.
Under no circumstances should the cleaning fluid get into the instrument.
Petroleum ether is flammab le, and care should be taken in its use .
The detector must be returned to the factory when filament replacement is
required. Call VICI Tech Support for return authorization.
Introduction
Components of the Detector Systems
Components of the detector system are listed in T ables 1 and 2. Check the
contents of the packages to verify that everything is present. Contact the
factory if anything is missing or damaged. (NO TE: damaged shipments
must remain with the original packaging for freight company inspection.)
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
3
Table 1:
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-NIFE system
Components of the TCD2-WRE system
Specifications
Mains (line): 115/230 V~50/60 Hz, 175 V A
Fuse: 2 A, time-delay, 5 x 20 mm
Pressure: 6.9 kPa (1 psi) operating, 6.9 MP a (1000 psi) max.
working
Maximum temperature 300°C
Heater power: 60 W max., 48 V, PWM
Output impedance: 100 Ω
Introduction
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 s witch is
on ( | ), the unit is operational except for the detector filaments (see next
paragraph) and the detector heater will operate if connected.
FILAMENT switch and indicator
Controls power to the detector filaments; when the switch is on, current
passes through the filaments. The indicator will light e v en if the detector
is not connected to the controller.
DETECTOR TEMPERA TURE control and indicator
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
temperature has been established.
Note that due to the fail-safe mechanism designed into the temperature
controller, the heater will not operate if mains po wer 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,
the detector should first be gently warmed without power applied.
The fail-safe mechanism will also act under any condition resulting from loss
of control (
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
factory or an authorized representative. Note that the maximum temperature
for operation of the TCD2 is 300°C.
FILAMENT TEMPERATURE switch
Separate 10-turn knobs control Filaments A and B. The value displa yed
corresponds to temperatures indicated in Figure 3 for nickel/iron filaments.
COARSE ZER O control
Once filament temperature has been applied, the Coarse Zero 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.
A TTENU ATION control
The Attenuation control determines the attenuation of the signal for the chart
output.
RECORDER switch
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
differential operation with the B channel representing the reference.)
The selected output signal is displayed in the LCD displa y.
e.g.
, over-heating, RTD failure, etc.). If proper procedures have
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