FLB Series Air Filter Systems

A Donaldson FLB air filter system is a two-stage air cleaner for construction and off-highway machines featuring a scavenge exhaust system, axial seal technology and a compact housing design, engineered for medium to demanding dust conditions.

The FLB series is part of complete air filter systems for construction machinery and is used as a closed air intake solution in off-highway machines, agricultural equipment and technical applications.

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System classification

The FLB series is used when limited installation space requires a two-stage filtration system with integrated pre-cleaning while maintaining compact system integration.

Typical applications include excavators, wheel loaders, agricultural machinery and mobile equipment with restricted engine compartments. The system is designed as a two-stage air cleaner with scavenge exhaust ejector system and axial seal technology.

Unlike individual air filter elements, the FLB series represents a complete system including housing, airflow management, pre-separation and filtration.

Two-stage filtration with scavenge system

The Donaldson FLB series operates as a two-stage air filtration system with integrated pre-separation. Incoming air is guided within the housing to remove particles before reaching the primary filter element.

Dust discharge is handled via a scavenge system with exhaust ejector connection. The system is designed to operate with an ejector and enables continuous dust evacuation without manual cleaning, significantly reducing load on the primary element during operation.

This system design ensures consistent filtration performance under medium to demanding dust conditions and is particularly suited for machines requiring compact installation and defined airflow performance.

Axial seal technology and housing design

The FLB series utilizes an axial seal system, differentiating it from Donaldson systems using radial seal technology.

The housings are designed as compact, corrosion-resistant units for mobile applications. Depending on configuration, housing sizes are available in approx. 152.4 mm, 203.2 mm, 254 mm and 304.8 mm or 6", 8", 10" and 12".

Airflow performance ranges from approx. 3 to 17 m³/min, depending on model. Continuous operating temperatures are specified up to approx. 82 °C, depending on configuration.

Technical features

Two-stage filtration: integrated pre-cleaning and primary filtration
Scavenge system: designed for exhaust ejector operation
Axial seal technology: defined sealing in closed system design
Compact housing sizes: 6", 8", 10" and 12"
Airflow capacity: approx. 3 to 17 m³/min (model-dependent)
Operating temperature: up to approx. 82 °C (model-dependent)

Applications and operating conditions

FLB air filter systems are used in applications requiring a combination of compact design, two-stage filtration and defined airflow performance.

Typical use cases include compact construction machinery, agricultural equipment and mobile machines operating in medium to demanding dust environments, including fibrous and particle-heavy conditions.

Positioning within Donaldson system range

The FLB series is positioned within Donaldson air filter systems as a compact two-stage solution with axial seal and scavenge ejector integration.

FKB series: Cycloflow systems for medium dust conditions
FLB series: compact two-stage systems with scavenge ejector and axial seal
FPG series: two-stage systems with integrated pre-cleaning in polymer design
FTG series: two-stage Cycloflow systems for large engines
PSD series: PowerCore systems for very high dust conditions

The FLB series is selected when a compact two-stage air filtration system with ejector support is required and neither the PowerCore architecture of PSD systems nor the large-scale FTG systems are necessary.

System environment

The FLB series is part of filters for construction machinery and belongs to the category of construction air filters within complete air filter systems.

It is integrated into the Donaldson air filter systems portfolio and used in applications requiring compact installation and integrated pre-separation.