Air filters

What is an air filter?

An air filter is a technical component for air filtration. The filter removes dust, particles, pollen, aerosols, and other contaminants from an air stream. Air filters are used in industrial plants, air filtration systems, compressors, HVAC systems, and vehicles. There, they protect components from wear and tear and thus ensure high air quality.

Why are air filters needed?

There are various applications in which air filters are used. In addition to standard air filters, industrial air filters, intake filters, activated carbon filters, and filter cartridges are also used.

In compressed air systems, air filters are used to filter the intake air in compressors. For hydraulic systems, various filters are available for venting and bleeding. Applications also extend to their use as dust collection filters in industry, in air conditioning and ventilation systems, in paint booths, and in vacuum filters. Air conditioning and ventilation filters, in particular, are used to reliably clean the incoming outdoor air, ensuring that no harmful substances enter the indoor air and that contaminants such as dust and particles are reliably filtered out of the air.

Where are air filters used?

Modern, high-performance machines and vehicles require high-performance filters, air filters, and filter components—and we have them. Air filters are used in a wide variety of industries—from construction machinery and agricultural machinery to compressors, vacuum pumps, general mechanical engineering, HVAC systems, engine and transmission manufacturing, as well as locomotives and commercial and specialty vehicles.

For ELSÄSSER Filtertechnik, it is therefore a matter of course to offer and deliver customized concepts and solutions tailored to your specific requirements.

How does an air filter work?

An air filter for off-road vehicles typically consists of two filter elements: the primary and secondary filters.

The primary filter is designed to remove contaminants from the air. The secondary filter ensures that no dirt enters the air intake duct leading to the engine during maintenance.

The contaminated air enters the air filter cartridge via the raw air inlet. The ideal solution is a cyclone installed upstream of the air filter elements. Thanks to the tangential flow, most of the dirt can be discharged via a dust discharge valve. The remaining dirt is captured by a filter cartridge. The cleaned air is drawn through the clean air inlet to the consumer.

What distinguishes a vehicle air filter?

A typical application is in vehicles. Here, the air is cleaned before it enters the engine. The filter medium ensures a high separation efficiency with minimal pressure drop. All of this leads to the best possible combustion, which is advantageous for complying with increasingly stringent emissions standards.

Air filters play a crucial role in engines. Once dust enters the engine, wear and tear occurs. This leads to the formation of deposits that are significantly harder than steel and cannot be removed. This shortens the service life of the engines. Clean air quality is also crucial inside vehicle cabins. In agricultural and construction machinery, cabin air filters protect against pollen and aerosols. There are also versions with activated carbon.

What types of air filters are there?

Air filters vary in terms of design, filter medium, filtration performance, and application. The selection of the appropriate air filter type depends, among other things, on airflow volume, dust load, particle size, and air purity requirements.

A distinction is often made between the following filters:

• Main air filter
• Secondary air filter
• Pre-filter
• Fine filter
• Intake filter
• Filter mats
• Dry filter
• Wet filter
• Single-stage filter
• Two-stage filter
• Combination filter
• Hybrid filters
• Activated carbon filters
• HEPA filters

What types of filter media are available?

For “automotive,” “construction and agricultural machinery,” and “compressors” applications, cellulose filter media is used as standard. Additional options include polyester media, high-efficiency glass fiber media, and Nanoweb media.

The choice of filter material is influenced by several factors. These include filter performance, dust holding capacity, separation efficiency, and the pressure drop of an air filter.

What types of air filter housing materials are available?

When developing new products, virtually all filter manufacturers rely almost exclusively on plastics, usually talc- or glass-fiber-reinforced.

We offer a full range of plastic filter housings. In addition, we provide materials such as steel—painted, galvanized, or chemically nickel-plated—as well as V2A, V4A, or materials tailored to your specific requirements.

Selecting the Right Air Filter

The selection of the right air filter depends on various factors, including the application, airflow rate, dust load, filter media, and air quality requirements.

The following questions will help you select a suitable air filter for industrial systems and air filtration systems.

How is an air filter’s dust-holding capacity determined?

The dust-holding capacity of an air filter is defined by the available filter area. In the next step, the air volume or volumetric flow rate (nominal volumetric flow rate) in m³/min, cfm, or l/h, as well as the available filter area in cm² or m², are specified. Additionally, the expected contaminant load is determined in mg/m³ or g/m³. The values mentioned are then evaluated in relation to one another. The laboratory dust-holding capacity, dust concentration, and service life can be determined on a test bench. The so-called ISO test dust is used as the test medium. This standardized test dust is characterized by a precisely defined particle size and count and is classified as ISO-fine or ISO-coarse.

The focus is on the analysis of the available effective resistance, which is available for dust loading between the initial resistance and the final resistance. When calculating the initial resistance, the resistance of any pipes, manifolds, flexible intake lines, cyclones, and rain caps used must also be taken into account. The final resistance is specified by the engine manufacturer or power unit manufacturer.

The air filter is then subjected to a dust concentration standardized according to ISO 5011 on the air filter test bench. This enables the test engineers to determine a very precise estimate of the expected operating hours. This enables us to provide our OEM customers with extremely precise recommendations regarding potential maintenance intervals and service hours.

Our engineers are available at any time to answer further questions.

How much does an air filter cost?

The cost of an air filter varies depending on the design, filter medium, filter class, size, and application. Simple filter cartridges are available even in the lower price range. In contrast, high-performance filters for industrial plants require a higher investment due to demanding specifications and higher quality standards.

What are the real benefits of air filters?

Air filters improve air quality, protect machinery from wear and tear, and thus contribute to operational reliability. The use of air filters reduces exposure to dust and particles and significantly extends the service life of components. Modern air filters combine a high separation efficiency with low pressure drop and energy-efficient operation.

Maintenance and Replacement of Air Filters

Regular maintenance ensures that air filters consistently achieve their full filtering performance and that systems remain reliably protected.

How often should an air filter be replaced?

An air filter must be inspected at specified intervals in accordance with the machine manufacturer’s guidelines. To monitor the air filters, a maintenance switch or service indicator, a visual maintenance indicator, or an electronic maintenance indicator is also available.

Such an indicator provides information about the differential pressure. When the maintenance indicator activates, it is recommended to replace the filter element. This also applies when the specified number of operating hours or the specified mileage is reached.

What happens if an air filter is not replaced in a timely manner?

A contaminated air filter increases the pressure drop in the system and thus reduces air flow. This can negatively impact the performance of machines and systems. In addition, it increases the strain on components, which can lead to rising operating costs.

Can you replace an air filter yourself?

Many air filters can be replaced easily and without special tools. However, this requires that the manufacturer’s specifications be followed. Furthermore, no contaminants must enter the system during the replacement. For complex industrial systems, the replacement should be performed by trained personnel.

How much does an air filter replacement cost?

The cost of an air filter replacement consists of the price of the filter element and the labor required. These costs vary depending on the filter type, accessibility, and size of the system.

Identifying Clogged and Defective Air Filters

Clogged or damaged air filters can significantly impair air filtration and reduce the service life of downstream components.

How can you tell if an air filter is clogged?

A clogged air filter can be identified by increased pressure drop and reduced airflow. For added safety, many systems also feature maintenance indicators or differential pressure measurements to monitor the filter’s condition.

How can you tell if an air filter is defective?

A defective air filter may show damage to the filter media. This includes cracks, leaks, and deformations. As a result, dust and particles can enter the system unfiltered, leading to increased wear and reduced protective effectiveness.

Wide Selection of Precisely Fitting Air Filters in the B2B Store

In our extensive selection, you’ll find the right filter for your specific air filter application. Enter the part number of your system and get the original part or a replacement alternative for your filter.

Either way—here in the B2B Store, you can purchase your precisely fitting air filter.

Technical Advice on Air Filter Technology

Still unsure about choosing the right compressed air filter?

Our team offers you detailed advice on selecting the right air filter for your needs.

Contact us by phone at 07032 / 96 04-0 or via our contact form.