Siemens Maxum II FPD Combustion Air Restrictor Stainless Steel 2021388-005

Overview: Precision Gas Flow Control for the FPD Flame

The Siemens Maxum II FPD Combustion Air Restrictor, part number 2021388-005, is a stainless steel tube assembly that precisely restricts and meters the combustion air supply feeding the Flame Photometric Detector (FPD) burner on the Siemens Maxum Edition II process gas chromatograph. Correct combustion air flow is critical to FPD performance, since Siemens documentation notes the FPD’s sensitivity can be increased by reducing combustion air flow, and most FPD flames cannot even be established with a normal air-to-hydrogen ratio – making this restrictor’s precise calibration directly relevant to detector operability.

As an independent specialized supplier of Siemens Maxum Edition II analyzer spare parts, Seven Star LLC sources and supplies the FPD combustion air restrictor 2021388-005 to refineries, gas plants, and petrochemical complexes across Oman and the wider GCC. Because this restrictor directly affects whether the FPD flame ignites and sustains correctly, Seven Star LLC helps maintenance teams keep the correct genuine part in stock for detector servicing.

Working Principle: Calibrated Flow Restriction

The restrictor works by presenting a precisely sized internal flow path to the combustion air supply line, creating a defined pressure drop that sets the air flow rate delivered to the FPD burner nozzle for a given upstream supply pressure. Because the FPD burner nozzle mixes hydrogen fuel from an outer annular gap with combustion air from an inner gap, the ratio between these two gas flows directly determines whether a stable flame can be established and sustained, and how sensitive the resulting sulfur-emission signal will be.

Stainless steel construction ensures the restrictor’s internal flow-path geometry remains dimensionally stable and free of corrosion over long service life, which matters because even small changes in the restrictor’s effective flow area would shift the air/hydrogen ratio delivered to the flame and could degrade or prevent ignition, or shift detector sensitivity away from its calibrated operating point.

Engineering Design of the Restrictor

The 2021388-005 restrictor is machined to the specific flow-calibration dimensions required for FPD combustion air service, distinguishing it from the visually similar hydrogen restrictor and from the equivalent restrictors used on the FID detector family, which are calibrated differently for that detector’s gas flow requirements. Correct restrictor selection is therefore essential – installing the wrong restrictor from the broader Maxum II parts family can result in incorrect flame stoichiometry even though the fitting may appear physically similar.

As with other components in the FPD gas supply path, Siemens specifies that the gases and supply lines feeding the FPD must be extremely clean and sulfur-free, since the detector’s high sensitivity to sulfur compounds makes it susceptible to contamination introduced anywhere in the gas delivery path, including at restrictor fittings.

Key Features

The FPD Combustion Air Restrictor 2021388-005 delivers the precise flow calibration the FPD flame depends on. Key characteristics include:

• Stainless steel construction for corrosion resistance and dimensional stability over long service life.
• Precisely calibrated flow restriction specific to FPD combustion air requirements.
• Directly affects flame ignition reliability and detector sensitivity when correctly installed.
• Distinct calibration from the corresponding FID combustion air restrictor within the same parts family.
• Genuine Siemens Maxum II part number for correct fit and flame stoichiometry.

Industrial Applications

The FPD combustion air restrictor is a required component wherever a Maxum Edition II analyzer is configured with a Flame Photometric Detector for sulfur-selective analysis, including natural gas sulfur specification testing and refinery sulfur recovery unit monitoring. Because it directly affects flame ignition and sensitivity, it is checked and, where necessary, replaced during FPD troubleshooting when ignition reliability or sensitivity issues are reported.

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 this and other Maxum Edition II FPD gas-path hardware, helping analyzer houses maintain reliable sulfur-selective detection.

Technical Specifications

The table below summarizes the core specifications of the Siemens Maxum II FPD Combustion Air Restrictor as supplied by Seven Star LLC.

Call To Action

Seven Star LLC is a dedicated supplier of Siemens Maxum Edition II process gas chromatograph spare parts and FPD gas-path hardware throughout Oman and the GCC. To request a formal B2B quotation, verify current stock availability, or confirm compatibility of the FPD Combustion Air Restrictor 2021388-005 with your specific Maxum II configuration, contact our instrumentation sourcing team today.