
Revision 4
108
12/15/2018
11.4 How are the Components Detected and Quantified?
The purpose of a detector is to monitor the carrier gas as it emerges from the column and to
generate a signal in response to variation in its composition due to eluted components. A
Thermal Conductivity Detector (TCD) is used in the ACCUCHROME Gas Chromatograph.
The Thermal Conductivity Detector consists of four spiral wound filament wires supported
inside cavities in a metal block. A constant DC current is applied to the filaments, which are
arranged in a Wheatstone bridge configuration. When pure carrier and reference gas are
flowing across the filaments, the heat loss, and thus filament temperature, is constant. This
consistent filament temperature produces a constant filament resistance. The currents in the
electronic bridge can be balanced to produce a zero signal level as a reference.
When a specific component enters the TCD with the carrier, the heat dissipated from the
filaments on the measured side changes. The amount of change is dependent on the
thermal conductivity of the gas, which is different for every component in the sample. This
change in heat dissipation causes a change in electrical resistance, which leads to an
imbalance in the electronic bridge. The resulting electrical signal is then used in conjunction
with a Response Factor to measure the concentration of the component. Figure 8-3 shows
an example of the TCD filament configuration.
Figure 11-3: Design of a Thermal Conductivity Detector
Содержание AccuChrome MA2963
Страница 21: ...Revision 4 8 12 15 2018 Figure 2 7 The Intrinsically Safe Barrier ...
Страница 24: ...Revision 4 11 12 15 2018 Figure 2 10 4 Minute Analysis Flow Diagram ...
Страница 26: ...Revision 4 13 12 15 2018 Figure 3 1 Physical Dimensions Class 1 Div 2 ACCUCHROME Chromatograph ...
Страница 58: ...Revision 4 45 12 15 2018 Figure 4 24 Chart Commands ...
Страница 65: ...Revision 4 52 12 15 2018 A sample report is shown in Figure 4 32 Figure 4 32 Sample Report ...
Страница 80: ...Revision 4 67 12 15 2018 Figure 5 10 Streams Setup ...
Страница 104: ...Revision 4 91 12 15 2018 Figure 8 2 Enron Mode Short Integers ...
Страница 114: ...Revision 4 101 12 15 2018 SS 2F LE MICRON INLINE FILTER HOUSING SS 2F K4 7 7 MICRON INLINE FILTER ELEMENT ...
Страница 124: ...Revision 4 111 12 15 2018 Figure 12 1 PLGC Power Connections Figure 12 2 Relays Wiring Diagram ...
Страница 125: ...Revision 4 112 12 15 2018 Figure 12 3 Analog Outputs Loop Powered Mode Figure 12 4 Analog Outputs Self Powered Mode ...
Страница 126: ...Revision 4 113 12 15 2018 Figure 12 5 Isolated RS 485 Port Connection Figure 12 6 Isolated RS 232 Connections ...
Страница 129: ...Revision 4 116 12 15 2018 Figure 12 11 Oven RTD and TCD Connections Figure 12 12 Arcnet AC485 Twisted Pair Connection ...
Страница 130: ...Revision 4 117 12 15 2018 Figure 12 13 Oven Heater Connection Figure 12 14 GC Valves Connections ...
Страница 131: ...Revision 4 118 12 15 2018 Figure 12 15 Solenoids 5 to 10 Connections Figure 12 16 Solenoids 1 to 4 Connections ...
Страница 132: ...Revision 4 119 12 15 2018 Figure 12 17 Digital Inputs Connections Figure 12 18 Cabinet Heater Connection ...
Страница 139: ...Revision 4 126 12 15 2018 Section 15 Valco 6 and 10 Port Valve Technical Information 15 1 Valve Operation Instructions ...
Страница 140: ...Revision 4 127 12 15 2018 ...
Страница 141: ...Revision 4 128 12 15 2018 15 2 Valve Maintenance Instructions ...
Страница 142: ...Revision 4 129 12 15 2018 ...