Air intake filter systems
Air intake filter systems for Gas Engines, Turbines, and Compressors
Hengst Air Intake Filter Systems is the long-standing engineering partner for custom-designed air intake filter systems for gas engines, turbomachinery and industrial process air. We read your specifications, design the matching system and respond fast. Every system is built on Hengst's own filter elements — developed, manufactured and integrated in-house since 1958, with a worldwide installed base across power generation, industrial process and fuel cell applications.
Contaminated intake air is one of the primary causes of performance degradation in gas engines, turbomachinery and compressors. Particle deposits on rotating components reduce output, abrasive particles accelerate erosion, and dissolved salts combined with moisture trigger corrosion. The resulting efficiency losses, increased energy consumption and unplanned downtime typically exceed the cost of filtration by a significant margin. A well-designed air intake filter system maintains a consistently low pressure drop over its service life, which directly translates into higher machine efficiency and lower operating costs. As an engineering partner with in-house filter element manufacturing, Hengst gives operators, OEMs and EPC contractors a single point of contact for the complete filtration solution — from system design and production to filter elements and maintenance support.
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Air Intake Filter Systems at a Glance
Hengst air intake filter systems cover the full range of industrial intake air filtration — from multi-stage static systems for moderate environments to self-cleaning pulse jet configurations for extreme dust loads, and from oil bath filters for heavy-duty engines to combined particle and gas filtration for fuel cells and electrolyzers. Every configuration is custom-designed for the specific application and site conditions.
Static Filter Systems
Multi-stage filtration with pre-filter (pocket/bag filters) and fine filter stages up to EPA grade E12. Optional coalescer and mist eliminator stages protect against salt and moisture at coastal locations. Anti-icing systems — including heat exchangers, warm air distributors, infrared heating systems and electric heaters — prevent ice formation in cold, humid climates. Static systems are suited for locations with low to moderate dust concentration, where they deliver high filtration efficiency with long maintenance intervals.
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How to Choose the Right Intake Filter System
Selecting an air intake filter system is a decision that affects reliability, machine performance, maintenance effort and operating costs for years. The right choice depends on several interrelated factors — with the local environment and the protected machine type as the primary drivers. The following performance characteristics are particularly relevant when comparing filter systems: filtration efficiency, dust loading capacity, differential pressure resistance, behavior under mist and moisture exposure, and pulse recovery rate (how effectively a self-cleaning filter regenerates after each cleaning cycle).
Climate Zone and Local Air Quality
The single most important factor in filter system selection is the operating environment. Dust concentration, particle composition, humidity, salt exposure and temperature extremes determine whether a static or self-cleaning system is required — and which optional stages (coalescer, anti-icing) are necessary.
Desert and arid regions with high dust loads and frequent sandstorms require self-cleaning pulse jet systems that can handle sustained particle ingress without rapid filter saturation. Coastal and offshore locations demand moisture- and salt-resistant configurations, typically with coalescer or mist eliminator stages upstream of the main filter. Arctic and sub-arctic sites need anti-icing protection to prevent ice formation on filter media when humidity and low temperatures coincide — a condition that can cause sudden pressure spikes up to filter blockage. Tropical environments combine high humidity with elevated temperatures and biological contamination, requiring a balanced approach between moisture management and particle filtration.
Machine Type and Application
Gas engines, gas turbines, compressors and other turbomachinery each have different requirements for filtration efficiency, volumetric flow rate and pressure drop tolerance. Gas turbines are particularly sensitive to fouling and corrosion because even small particle deposits on turbine blades reduce aerodynamic efficiency. Compressors in oil and gas or process applications face abrasive dust that accelerates mechanical wear. Large diesel and gas engines in power generation or marine applications operate under sustained high loads where reliable combustion air quality is essential. Fuel cells and electrolyzers require not only particle-free but also gas-contaminant-free air, as chemical impurities degrade cathode and catalyst performance.
Static vs. Self-Cleaning Filter Systems
This is the key decision in most intake air filtration projects. Both system types have their own benefits, depending on the operating environment and cost priorities.
The decision is not about a generally superior system type, but about matching the system to the specific site conditions and operational priorities. As your engineering partner, we work with your specification — site profile, machine class, dust load, climate exposure — to design the configuration that fits your application.
| Criterion | Static Filtration System | Self-cleaning (pulse-jet) system |
| Operating Principle | Depth filtration: Particles are trapped within the filter medium | Surface filtration: A dust cake forms on the filter surface and is removed by compressed air |
| Filtration Efficiency | Up to EPA E12 (multi-stage) | Up to EPA E11 |
| Pressure drop behavior | Rises gradually as the filter be comes loaded | remains consistently low due to continuous cleaning cycles |
| Service life | Typically 6 to 24 months,depending on the environment (with in the industry standard range) | up to 2 to 3 years thanks to self-cleaning (within the industry standard range) |
| Maintenance requirements | Regular replacement of Filter Elements | Minimal; primarily monitoring the compressed air supply and occasional cartridge inspection |
| Capital costs | Lower initial investment | Higher initial investment |
| Operating costs | Lower in moderate environments; higher in dusty conditions due to more frequent filter changes | Lower in dusty environments thanks to long service life and stable pressure drop |
| Best suited for | Locations with low to moderate dust loads, temperate climates | Desert, heavy industry, mining, Arctic (under conditions of persistently high dust, sand, or snow loads) |
| Anti-icing | A separate anti-icing system is required if needed | Self-cleaning provides inherent protection against ice formation |
| Compressed air supply | Not required | Required for cleaning |
Total Cost of Ownership (TCO): More Than Just the Purchase Price
The purchase price of an air intake filter system represents only a fraction of its lifetime cost. The dominant cost drivers are pressure drop behavior, filter service life and maintenance-related downtime.
Every millibar of additional pressure drop at the air intake reduces machine output and increases energy consumption. A filter system that maintains a stable, low pressure drop over its entire service life preserves machine efficiency and reduces operating costs continuously. Filter service life directly determines the frequency of element replacements and the associated maintenance downtime — each filter change requires a partial or full shutdown. In high-dust environments, static filter elements may require replacement every few months, while self-cleaning systems maintain operation for significantly longer periods.
Hengst systems are engineered for low total cost of ownership: stable pressure drop through optimized filter design, extended service intervals, and system configurations matched to the specific operating environment. Combined with in-house filter element production, this ensures consistent quality and reliable supply of replacement elements over the operating life of the plant.
Filter Elements manufactured in-house
The performance of an air intake filter system is determined by the Filter Elements inside it. Hengst combines its in-house production of Filter Elements with expertise in complete system integration—a vertically integrated engineering approach that has evolved over decades within the Hengst Group. The properties of the filter element—such as pressure drop, dust holding capacity, and moisture behavior—are not off-the-shelf mass-produced components, but rather design parameters that we consistently control ourselves.
For operators who already own a filter housing and need high-performance replacement elements, Hengst offers its own portfolio of Filter Elements for gas turbines and turbomachinery, manufactured to the same quality standards as the elements in complete Hengst systems. In this way, Hengst serves operators both as a system provider and as a supplier of replacement Filter Elements for existing systems, including filter housings from other manufacturers.
Industries and Applications for Our Intake Air Filter Systems
Hengst’s air intake filter systems protect critical machinery across a wide range of industries, with a global installed base in the following application areas. Our complete filter systems are suitable for small to medium-sized gas turbines. For larger turbomachinery filter housings, you can find the right replacement element atgas turbine and turbomachinery filter.
Energy Generation
Gas engines, generators and small to mid-range gas turbines in baseload and peaking power applications. Reliable air filtration safeguards engine and turbine efficiency and extends maintenance intervals.
Engineering and Worldwide Service
Hengst Air Intake Filter Systems supports operators, OEMs and EPC contractors beyond the delivery of filter hardware — with engineering expertise, fast response and a worldwide footprint throughout the system lifecycle.
System Design Consultation
Application engineers at Hengst analyze site-specific conditions such as climate data, ambient air quality and volumetric flow requirements, and develop the system configuration that matches the application. This service is available for new installations as well as for replacing or upgrading existing filter systems. For OEMs and EPC contractors, Hengst provides technical design and integration support during the project engineering phase, working specification-by-specification.
Retrofit and Optimization
Existing filter houses can be evaluated for performance improvements: filter element upgrades, system reconfiguration, or pressure drop analysis to identify efficiency gains. Hengst's combination of system engineering and in-house filter element production allows retrofits to be designed as integrated solutions rather than component-by-component replacements.
Worldwide Service Footprint
Hengst Filtration is a family-owned company with more than 3,700 employees and 28 sites worldwide — building filtration technology since 1958. This global footprint gives operators regional service presence for maintenance, spare parts and engineering support wherever their plants operate.
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Our application engineers would be happy to discuss your specific filtration requirements with you, from the initial system selection to a retrofit analysis for existing systems.
Frequently Asked Questions About Air Intake Filter Systems
What types of air intake filter systems are available for gas engines, turbomachinery, and compressors?
The main types of systems are static filter systems, self-cleaning pulse jet filters, and oil-bath recirculation filters. Static systems use multi-stage depth filtration with pre-filters and fine filters up to EPA Class E12 and are suitable for environments with low to moderate dust loads. Self-cleaning pulse filters operate using surface filtration and automatic pulse-jet cleaning and are designed for high-dust conditions such as deserts or heavy-industry sites. Oil-bath recirculation filters (RotaClean) use oil-coated panels to filter the combustion air of large engines. For fuel cells, electrolysers, and DAC applications, Blue.netic combines particle filtration and pollutant gas separation in a scalable, modular system.
How does a self-cleaning pulse filter system work?
Pulse filters operate on the principle of surface filtration: Particles settle on the outer surface of cylindrical filter cartridges and form a dust cake. At defined intervals or when a pressure drop threshold is reached, a brief burst of compressed air is directed through the cartridge in the opposite direction, dislodging the dust cake from the filter surface. This cleaning cycle runs automatically and continuously, keeping the pressure drop consistently low without manual intervention. The two main designs are cross-flow systems (horizontal cartridge arrangement) and bench-top filter systems (vertical cartridge arrangement).
What filter quality classes are used for intake air filtration in gas turbines and gas engines?
Industrial intake filtration generally refers to three classification systems. ISO 16890 defines efficiency classes based on particle size fractions (ePM1, ePM2.5, ePM10). EN 1822 / ISO 29463 defines EPA and HEPA classes, with E10 through E12 being common for gas turbine applications and HEPA classes (H13 and higher) rarely used due to high pressure drop. ASHRAE 52.2 uses MERV ratings (1 to 16), which remain widely used in North American specifications. Static Hengst filter systems achieve filtration down to EPA Class E12.
How does intake air filtration affect machine performance and energy consumption?
Every millibar of pressure loss at the intake reduces engine power and increases specific energy consumption. Insufficiently filtered air leads to fouling—that is, particle deposits on compressor and turbine blades—which degrade aerodynamic efficiency over time. Salt deposits can cause corrosion in the turbine’s hot gas path. A filtration system that keeps pressure drop stable and low and prevents the ingress of contaminants maintains the machine’s design efficiency, reduces energy costs, and extends compressor maintenance intervals.
What is the difference between depth filtration and surface filtration?
In depth filtration, which is used in static filter systems, particles penetrate the filter medium and become trapped within its fiber structure. The filter gradually becomes clogged with dust, causing the pressure drop to increase over time until the element must be replaced. In surface filtration, which is used in pulse filters, particles are deposited on the outer surface of the filter cartridge and form a dust cake that can be cleaned off. Pulse cleaning restores the filter surface at regular intervals, keeps the pressure drop low, and extends the filter’s service life. Depth filtration generally achieves higher filter efficiency classes, while surface filtration is designed for environments with high dust loads where continuous regeneration is critical.
How often do intake filters need to be replaced?
Replacement intervals depend on the system type and the operating environment. Static Filter Elements typically last 12 to 24 months in moderate environments. In dusty or contaminated environments, replacement may be necessary every 6 to 12 months. Self-cleaning pulse filters extend service life to 2 to 3 years because the automatic cleaning cycle continuously regenerates the filter surface. Oil-bath recirculating filters (RotaClean) do not use replaceable Filter Elements, as the oil-coated panels are cleaned within the recirculating system, completely eliminating the need for conventional filter replacement.
What role does intake air filtration play in fuel cell systems?
Fuel cells, particularly PEM fuel cells, are highly sensitive to airborne contaminants. Salts, nitrogen oxides, sulfur compounds, and ammonia can irreversibly damage the membrane electrode assembly and reduce catalyst performance. Particle filters alone are not sufficient, as these chemical contaminants are present in gaseous form or dissolved in aerosol droplets. Blue.netic from Hengst addresses this by combining particulate filtration and targeted pollutant gas removal in a single, scalable system designed for large fuel cell plants, electrolysers, and direct air capture plants.
Can Hengst retrofit an existing filter housing with new Filter Elements or systems?
Hengst offers retrofit and optimization services for existing filtration systems. These include a performance evaluation of the current system, an upgrade of the Filter Elements, a reconfiguration of the system, and a pressure drop analysis. Because Hengst combines system engineering with in-house filter element manufacturing, retrofit projects benefit from integrated solutions in which housing modifications and filter element specifications are developed in tandem. For details, please contact the Application Engineering Team at airintake.herne@hengst.de.
Does Hengst supply Filter Elements for intake systems from other manufacturers?
Hengst manufactures Filter Elements for gas turbines and turbomachinery, including for filter systems originally supplied by other manufacturers. These elements are manufactured at Hengst’s own production facilities. For operators looking for replacement Filter Elements for an existing filter housing, gas turbine and turbomachinery filter offers its own selection of elements.
