Valco Instruments Co. Inc. TCD Instruction Manual

Microvolume thermal conductivity detector

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Valco Instruments Co. Inc.

North America, South America, and Australia/Oceania contact:

Microvolume Thermal

Conductivity Detector

Instruction Manual

Valco Instruments Co. Inc.

800 · 367 · 8424 sales

713 · 688 · 9345 tech

713 · 688 · 8106 fax

valco@vici.com

Europe, Asia, and Africa contact:

VICI AG International

Schenkon, Switzerland

Int + 41 · 41 · 925 · 6200 phone

Int + 41 · 41 · 925 · 6201

info@vici.ch

tcd2.p65

Rev 4/12

Printed in USA

fax

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Summary of Contents for Valco Instruments Co. Inc. TCD

Page 1 Valco Instruments Co. Inc. Microvolume Thermal Conductivity Detector Instruction Manual tcd2.p65 Rev 4/12 Printed in USA North America, South America, and Australia/Oceania contact: Europe, Asia, and Africa contact: Valco Instruments Co. Inc. VICI AG International 800 · 367 · 8424 sales Schenkon, Switzerland 713 ·...
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Page 3: Table Of Contents
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 ....................
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Page 5: Introduction
Introduction Description and Operating Principle 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.
Page 6: Safety Notes And Information
Introduction Safety Notes and Information Symbols HOT SURFACE The surface of the detector body may be hot while in operation (possibly in excess of 250°C). Observe caution. ATTENTION Refer to the manual. PROTECTIVE EARTH This internal connection provides protection against electric shock from mains voltages and should not be removed.
Page 7: Components Of The Detector System
Introduction 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.) Specifications Mains (line):...
Page 8: Description Of Controls And Connectors
Introduction 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 the detector heater will operate if connected.
Page 9 Introduction Figure 2: Front panel controls FILAMENT TEMPERATURE KNOB SETTING Figure 3: Actual filament temperature vs. filament temperature knob settings...
Page 10 Introduction MAINS POWER connector For connection to 115/230 VAC 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.
Page 11: System Requirements
System Requirements Components Not Included with the Detector System • Carrier gas (99.999% purity is recommended) • Ultra high purity grade gas pressure regulator with stainless steel diaphragm (recommended) • Any special adapters required for connection to the gas regulator •...
Page 12: Gc Column Selection
System Requirements However, while nitrogen as a carrier yields excellent response to hydrogen, the response to oxygen and carbon dioxide is diminished compared to the levels that could be achieved with helium or hydrogen. Argon would yield poor response to carbon dioxide and water, but would be adequate for other components.
Page 13: Installation
Installation The detector is usually mounted on top of the GC column oven. The power cord for the controller is 1.8 m (6') long; the detector cable and the signal output cables (attenuated and unattenuated) are 1.2 m (4') long. General Precautions •...
Page 14: Gas Connections
Installation Gas Connections Remember these three points discussed earlier: (1) all surfaces that contact the gas stream must be glass or stainless steel; (2) do not use copper tubing or brass fittings; and (3) all tubes must be thoroughly cleaned and baked before use.
Page 15 Installation Installing and Purging the Gas Regulator 1. Make sure the on/off valve on the helium cylinder is completely closed. Screw the CGA fitting nut of the regulator into the helium cylinder. Go beyond finger-tight, but do not tighten the nut all the way – some leakage is required for the purging operation.
Page 16: Column Connection
(.8 mm OD). Refer to the information below to determine the correct Valco fitting for use with other columns. Column Connection Fittings Packed Columns A 1/16" packed column requires only the ZU1C which comes with the TCD. For 1/8" columns, order a ZRU21.
Page 17: Electrical Connections
Connection of these columns requires the use of the ZU1C with the appro- priate fused silica adapter. For a .53 mm ID x .8 mm OD column, use the FSR1.8 supplied with the TCD. For other sizes, use this table to determine the proper adapter:...
Page 18 Installation 2. Connect the data output(s). The A / B / A - B outputs are used with an integrator or PC-based data acquisition system; the chart output is for a strip chart recorder. Polarities and full scale range are indicated in the figure below.
Page 19: Initial Power-Up
Column diameter will determine the optimum column flow rate. The microvolume TCD is designed for the lower flow rates typical for capillary columns, and achieves best sensitivity at rates below 10 ml/min. Since the filaments are maintained at constant temperature, the detector can be operated at extremely low flow rates (less than 0.5 ml/min) without damage...
Page 20 Installation The test chromatogram accompanying your TCD was obtained under the following conditions: Sample: ~100 ppm blend in Helium balance Sample volume: 250 µl Column: 10' x 1/16" x 0.040" molecular sieve 5Å micropacked Column flow: 6 mL/min Reference flow: 6 mL/min Column temperature: 65°C...
Page 21: Troubleshooting
Troubleshooting Troubleshooting Chart Problem Possible Cause Refer to page: No signal Main or filament power switch off Filament temperature too low Fuse blown Output cable in the wrong connector Signal reversed Signal wires reversed Noisy signal Dirty system or leaking fittings 7, 13, 19 Bad flow controller in system Cell/filament differential too small...
Page 22: Detector Fault Determination
Troubleshooting Detector Fault Determination Electrical faults in the detector are most easily discovered by making resistance measurements between pins of the detector cable connector. The table below shows the pin numbering and connections for the detector cable (view into pins). Nominal resistance values (in ohms) at 25°C are shown. Unshaded boxed without numbers represent open circuits, and should in no case be blow 1 MΩ.
Page 23: Maintenance
Petroleum ether is flammable, and care should be taken in its use. Bake Out Procedure Under normal conditions, the TCD requires no routine maintenance. However, if the detector is exposed to chemicals which may condense or polymerize within the detector and adversely affect performance, the detector cell can be baked out at elevated temperatures (up to 300°C).
Page 24: Warranty
Warranty This Limited Warranty gives the Buyer specific legal rights, and a Buyer may also have other rights that vary from state to state. For a period of 365 calendar days from the date of shipment, Valco Instruments Company, Inc. (hereinafter Seller) warrants the goods to be free from defect in material and workmanship to the original purchaser.
Page 25: Detector Performance Log
Detector Performance Log TCD2 Detector Model: Serial Number: Date of purchase: Date Operator Comments Filament Detector Noise Sample Detector temp temp level flow (°C) (°C) Initial power-up (IPU) — — IPU, detector to analysis temp — — IPU, column installed Ambient —...