Air filters

Where are air filters used?

Modern, high-performance machines and vehicles need high-performance filters, air filters and filter components - and we have them. Air filters are used in a wide range of industries - from construction machinery and agricultural machinery to compressors, vacuum pumps, general mechanical engineering, engine and transmission construction, locomotives and commercial and special-purpose vehicles. It is therefore a matter of course for ELSÄSSER Filtertechnik to offer and supply customised concepts and solutions for your specific requirements.

What are air filters needed for?

There are various applications in which air filters are used. In vehicles, they clean the air before it enters the engine. Modern quality filters permanently remove particles from the intake air, ensuring an optimised fuel-air mixture. This leads to the best possible combustion, which is an advantage when it comes to complying with ever stricter emission standards. Air filters play a crucial role for engines. This is because once dust enters the engine, it takes part in the combustion process in the cylinders. This causes additional wear in the form of deposits, which are significantly harder than steel and no longer detach. This has the effect of shortening the service life of the engines.

Pollutant-free air quality is also crucial in the interior of vehicles. In agricultural and construction machinery, cabin air filters are used to protect against pollen and aerosols; there are versions with and without activated carbon.

In compressed air, air filters are used to filter the intake air in compressors. In the field of hydraulics, various filters are available for ventilation and air extraction. They can also be used as dedusting filters in industry, for example in air conditioning and ventilation systems, painting systems and vacuum filters. They are used to reliably clean the incoming outside air or to ensure that no harmful substances get into the outside air.

How does an air filter work?

Which filter media are available?

In the ‘Automotive’, ‘Construction and agricultural machinery’ and ‘Compressors’ applications, the cellulose filter medium is used as standard. Polyester media, highly efficient glass fibre media and nanoweb media are also available as options.

What air filter housing materials are available?

When developing new products, all filter manufacturers rely almost exclusively on plastics, usually with a glass fibre mixture. We can supply you with all plastic filter housings as well as materials such as steel, painted, galvanised, chemically nickel-plated, V2A, V4A or materials according to your requirements.

How is the dust capacity of an air filter determined?

The dust capacity is defined by the available filter area. In the next step, the air volume or the volume flow (nominal volume flow) in m³ / min, cfm or l/h and the available filter area in cm² or m² are specified. In addition, the amount of dirt to be expected is determined in mg/m³ or g/m³. The above values are then evaluated in relation to each other. The laboratory dust capacity, dust concentration and practical hours can be determined on the test bench. ISO test dust is used as the test medium. The standardised test dust is characterised by a precisely defined particle size and number and is classified as ISO fine or ISO coarse.

The focus is on analysing the available effective resistance that is available for the dust load between the initial resistance and the final resistance. When calculating the initial resistance, the resistances of any pipes, elbows, flexible intake ducts, cyclones and rain caps used must also be considered. The final resistance is determined by the engine manufacturer or genset builder.

The air filter is then subjected to different dust concentrations on the air filter test bench. In this way, the test engineers are able to determine a very precise indication of the practical hours to be expected. In this way, we are able to provide our OEM customers with extremely precise recommendations regarding possible maintenance intervals and service hours.

How often should an air filter be replaced?

An air filter must be checked at set intervals in accordance with the machine manufacturer's specifications. A maintenance switch, also known as a service indicator, visual maintenance indicator or electronic maintenance indicator, is also available to monitor the air filter. Such an indicator provides information about the air flow rate and the air supply to the engine. If the maintenance indicator lights up, it is recommended that the filter element is replaced. This also applies when the specified number of operating hours or mileage is reached.

What types of air filters are there?                

A distinction is made between:

• Main air filters
• Main filter elements
• Secondary air filters
• Safety air filters
• Safety elements
• Oval filters, filter cells
• Filter mats
• Pre-filters
• Main filters
• Cyclones
• Fine filters
• Dry filters
• Wet filters
• Centrifuges
• Single-stage filters
• Two-stage filters
• Combination filters
• Hybrid filters