Brand: Siemens

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

Name: Siemens Maxum II FPD Air Restrictor 2021388-005 | Seven Star
Brand: Siemens

Description

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.

Parameter	Specification
Model / Part Number	Combustion Air Restrictor, FPD, Stainless Steel, P/N 2021388-005
Function	Calibrated combustion air flow restriction to the FPD burner
Material	Stainless steel
Compatible Detector	Flame Photometric Detector (FPD)
Target Platform	Siemens Maxum Edition II Process Gas Chromatograph
Hardware Condition	New, genuine Siemens part number

Why Choose Seven Star LLC for FPD Gas-Path Calibration Parts

The combustion air restrictor and the visually similar hydrogen restrictor and FID-family restrictors are calibrated completely differently despite looking alike – installing the wrong one from the broader Maxum II parts family produces incorrect flame stoichiometry that can prevent ignition entirely or quietly shift detector sensitivity away from its calibrated operating point. Seven Star LLC verifies the exact restrictor part number and detector application against the customer’s specific FPD troubleshooting symptoms before shipping, rather than assuming a similar-looking fitting will work. We also emphasize Siemens’ requirement that gases and supply lines feeding the FPD stay extremely clean and sulfur-free, and help refinery and gas plant instrumentation teams across Oman keep correctly identified restrictor stock on hand for FPD ignition and sensitivity troubleshooting, coordinating delivery across Muscat, Sohar, and the broader GCC.

Request a Quote for Siemens Maxum II FPD Combustion Air Restrictor Stainless Steel 2021388-005

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 availability and lead time, or confirm compatibility of the FPD Combustion Air Restrictor 2021388-005 with your specific Maxum II configuration, contact our instrumentation sourcing team today.

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About brand

Most Siemens automation parts are bought by article number, the string beginning 6ES7, 6AV2 or 6GK5 printed on every module. Founded in 1847 and headquartered in Munich, Siemens builds the SIMATIC controllers, SCALANCE networks and SINAMICS drives that plant engineers meet on almost every site. Seven Star LLC, an independent supplier, lists Siemens PLC and I/O modules, HMI panels, industrial Ethernet switches, drives, protection relays, temperature transmitters and gas analyzer spare parts for projects in Oman and the GCC.

Siemens product families on this page

Controller hardware covers the SIMATIC S7-1200 (CPU 1214C with SM 1223 signal modules) and the S7-1500 (CPU 1515-2 PN), with ET 200SP and ET 200M distributed I/O and their IM 155-6 and IM 153-2 interface modules. Operator panels include the KTP700 Basic and TP700 Comfort. SCALANCE XC208 managed switches handle industrial Ethernet. Drives are represented by the SINAMICS G120C compact inverter and the G120X for pumps and fans. From the power side come the SIPROTEC 7SJ85 feeder protection relay and SIVACON S8 switchboards, and from process instrumentation the SITRANS TH320 head-mounted temperature transmitter.

Where Siemens equipment is used

SIMATIC controllers and ET 200 I/O run packaged units, skids and whole process lines in water treatment, oil and gas, cement, food and manufacturing plants. SINAMICS drives control pumps, fans and conveyors, SCALANCE switches form the control network, and SIPROTEC relays protect medium voltage feeders and motors.

Ordering Siemens parts: what we need

Send the complete article number, the functional status or version printed on the module and, for CPUs, the firmware version your project was written for. For drives add power, supply voltage, filter option and fieldbus version. For SIPROTEC relays the long order number or product code is required, because it fixes the hardware and function package. A nameplate photo answers most of these points at once.

Frequently Asked Questions

What does this restrictor control?

It precisely restricts and meters the combustion air supply feeding the FPD burner, directly affecting flame ignition reliability and detector sensitivity.

Why does combustion air flow matter so much for the FPD?

FPD sensitivity can be increased by reducing combustion air flow, and most FPD flames cannot be established with a normal air-to-hydrogen ratio, making precise restrictor calibration essential to detector operability.

Is this restrictor the same as the FID combustion air restrictor?

No, although visually similar, the FPD combustion air restrictor is calibrated differently from the corresponding FID restrictor within the same Maxum II parts family, so correct part selection matters.

Why is stainless steel used for this restrictor?

Stainless steel keeps the restrictor's internal flow-path geometry dimensionally stable and corrosion-free, since even small changes in flow area would shift the air/hydrogen ratio delivered to the flame.

Does Seven Star LLC supply this part across the GCC?

Yes, Seven Star LLC sources and supplies the Siemens Maxum II FPD Combustion Air Restrictor 2021388-005 to refinery, gas processing, and petrochemical customers across Oman and the wider GCC region.

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