Siemens Maxum II Filament Detector 2-Cell Assembly 2021335-001

Overview: A Concentration-Response Detector for General Analysis

The Siemens Maxum II Filament Detector 2-Cell Assembly, part number 2021335-001, is a complete two-cell filament thermal conductivity detector (TCD) module for the Siemens Maxum Edition II process gas chromatograph. This assembly is the current-generation replacement for the earlier 2021122-001 2-cell filament detector kit, providing concentration-response detection suited to a broad range of process components with moderate sensitivity requirements, and can also serve as an inter-column detector (ITC) in configurations paired with an FID or FPD application.

As an independent specialized supplier of Siemens Maxum Edition II analyzer spare parts, Seven Star LLC sources and supplies the filament detector assembly 2021335-001 to refineries, gas plants, and petrochemical complexes across Oman and the wider GCC. Keeping the correct current-generation assembly in stock helps maintenance teams avoid compatibility issues that arise from ordering the discontinued 2021122-001 kit.

Working Principle: Thermal Conductivity Detection

The 2-cell filament TCD operates on the principle of differential thermal conductivity measurement: two heated filament elements are exposed to carrier gas flow, one acting as a reference cell and the other as a measurement cell through which the column effluent passes. As sample components elute from the separation column and mix with the carrier gas, they alter the thermal conductivity of the gas stream passing over the measurement filament, changing its rate of heat loss and therefore its electrical resistance relative to the reference filament.

This resistance difference is measured using a Wheatstone-bridge-type circuit and converted into an electrical signal proportional to the concentration of the eluting component, giving the TCD its characteristic universal, concentration-response behavior – it responds to virtually any component whose thermal conductivity differs from the carrier gas, rather than being limited to hydrocarbons or sulfur compounds as with flame-based detectors. This makes the 2-cell filament detector well suited to general-purpose analysis and to serving as an inter-column detector supporting a companion FID or FPD detector elsewhere in the same analyzer.

Engineering Design of the Filament Detector Assembly

The 2021335-001 assembly is supplied as a complete detector module engineered for direct installation into the Maxum Edition II detector compartment, connecting to the Detector Personality Module (DPM) through the analyzer’s standard feed-through assembly. The filament elements are precision-matched to maintain balanced reference and measurement cell characteristics, which is essential to accurate, drift-free thermal conductivity measurement over the detector’s service life.

Because the filament board within the TCD housing is a serviceable item, the assembly is designed so that the filament/thermistor board can be replaced without disturbing the surrounding oven plumbing in many cases, though the detector must always be fully de-energized before opening per standard safety procedure. The 2-cell configuration keeps the detector compact enough to fit within the Maxum II’s air bath or airless oven detector module arrangement alongside other detector types.

Key Features

The Filament Detector 2-Cell Assembly 2021335-001 provides dependable, universal-response detection for the Maxum Edition II platform. Key characteristics include:

• Complete 2-cell filament TCD assembly, factory-current replacement for the discontinued 2021122-001 kit.
• Universal concentration-response detection suited to a wide range of process components.
• Can be configured as an inter-column detector (ITC) alongside an FID or FPD application.
• Precision-matched filament elements for balanced, drift-free reference and measurement cell performance.
• Compatible with both air bath and airless Maxum Edition II oven configurations.
• Genuine Siemens Maxum II part number for correct fit and DPM compatibility.
• The only detector type supported by the Maxum II modular oven, which is restricted to thermal conductivity detection.
• Siemens requires the TCD to be opened only with power removed, and serviced by Siemens-trained maintenance personnel.

Industrial Applications

The 2-cell filament detector is used across general process gas chromatography applications where a broad, universal-response detector is preferred over the more selective flame ionization or flame photometric detectors, including permanent gas analysis, general hydrocarbon and non-hydrocarbon component monitoring, and inter-column detection duties supporting a primary FID or FPD channel in multi-detector analyzer configurations. Its concentration-response nature makes it a practical choice for refinery and gas processing streams containing a wide variety of component types.

Seven Star LLC supports refinery instrumentation teams, gas processing operators, and petrochemical maintenance departments across Oman, Muscat, Sohar, and the broader GCC region with sourcing of Maxum Edition II detector hardware, helping analyzer houses maintain measurement continuity across their full detector configuration.

Platform Context and Operating Envelope

Specifying the Siemens Maxum II Filament Detector 2-Cell Assembly correctly means understanding where it sits within the analyzer. The Maxum edition II accepts thermal conductivity, flame ionization, flame photometric, helium ionization, photoionization and electron capture detection, and the oven type determines how many and which detector modules a given analyzer can carry. An airbath oven working between 5 and 225 °C in isothermal or temperature-programmed mode supports up to three detector modules; an airless oven, which Siemens rates at 0.02 °C isothermal control accuracy, normally carries one or two; and the modular oven, operating between roughly 60 and 80 °C depending on application, supports thermal conductivity detection only. That last point matters at the sourcing stage, because on a modular-oven Maxum the filament TCD is not one option among several, it is the detector.

Siemens specifies carrier gas for the platform as hydrogen, nitrogen, helium, argon or synthetic air from compressed cylinders at 99.999% purity, with consumption of roughly 5 to 100 litres per month per detector module, and rates the analyzer for ambient temperatures of -18 to 50 °C depending on application. Thermal conductivity measuring ranges on gaseous samples extend down to 0 to 20 ppm, with the modular-oven version reaching 0 to 200 ppm, and repeatability is quoted from ±0.5% on spans of 2 to 100% out to ±5% on a 0.5 to 5 ppm range. The analyzer itself is certified for ATEX and IECEx Zone 1 and Zone 2 with air or nitrogen purging, and for CSA Class I Divisions 1 and 2, Groups B to D.

Technical Specifications

The table below summarizes the core specifications of the Siemens Maxum II Filament Detector 2-Cell Assembly as supplied by Seven Star LLC.

Request a Quote for Siemens Maxum II Filament Detector 2-Cell Assembly 2021335-001

Seven Star LLC is a dedicated supplier of Siemens Maxum Edition II process gas chromatograph spare parts and detector assemblies throughout Oman and the GCC. To request a formal B2B quotation, verify current availability and lead time, or confirm compatibility of the Filament Detector 2-Cell Assembly 2021335-001 with your specific Maxum II configuration, contact our instrumentation sourcing team today.

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