Siemens Maxum II Service Manual

Also see for Maxum II: Reference manual Manual Manual Installation manual

Contents

Thermal Conductivity Detector 2The Thermal Conductivity Detector (TCD) is a concentration-responsive detector of moderatesensitivity. The detector cell, containing the sensing element, is a flameproof/explosion-proofunit located in the chromatograph oven. The TCD is the only Maxum II detector type that isnot mounted in the detector compartment.7R'30&DEOH'HWHFWRU7KHUPLVWRU3DLU6DPSOH5HIHUHQFH*DV 5HDURIRYHQRILQ$LEDWK$LUOHVVRILQ$QDO\WLFDO0RGXOH5HDURIRYHQThe TCD works on the principle that the thermal conductivity of the carrier gas is different thanthe thermal conductivity of the sample components. This means that the carrier gas conductseither more or less heat from the heated element than the sample components. The electroniccircuits sense the change in heat flow and produce a proportional analog voltage signal. Twotypes of TCD are used within the Maxum II.● Thermistor Model – This TCD type uses thermistors. It includes six independentmeasurement cells and two reference cells. This detector connects to the IS TCD DPM,located in the electronics cabinet.● Filament Model – For higher temperature requirements a 2-cell TCD is available that usesfilaments for thermal conductivity sensing. The 2-Cell Filament TCD is often used as anInter‑Column Detector in conjunction with an FPD or FID application. This detector typicallyconnects to a dedicated input channel on the Base DPM.Maxum Edition II DetectorsService Manual, May 2018, A5E42019847001 7