Computer aided development of hydraulic filter elements - From theory to patent and products.

Oleg Iliev, Andreas Schindelin, and Andreas Wiegmann
Fraunhofer ITWM, Kaiserslautern, Germany


A highly improved next generation filter element was developed based on computer simulations 
with experimental validation. The new filter element exhibits a significantly lower pressure 
drop than the previous generation while achieving the same filter efficiency and same filter 
Very high oil pressures are intrinsic to mobile hydraulic applications. Under such high 	
pressures, the individual pleats of a pleated filter tend to collapse and thus, significantly 
diminish the accessible filter media surface. In order to prevent such collapse, supporting 
meshes can be used both on the outside and inside of the filter media. Computer simulations 
allowed to study a new design, in which the weave type in the outflow channel of the pleat 
was changed from plain weave to 2/2 twill. The simulations suggested that the new design 
results in a 30 % lower the pressure drop of the filter element while maintaining the good 
performance with regard to filter efficiency and filter capacity. The pre-dictions were found 
to be correct by ensuing measurements on prototypes. One main benefit of the computer simulations 
was the establishment of this im-provement. Few prototypes needed to be built. Also, the 
simulations identified a set of optimal yet stable parameters. Thus, small variations in the 
production process do not disturb the performance of the filter element.
The joint work led to a patent and a new product by Argo-Hytos. The hydraulic filter element 
EXAPOR®MAX 2 features a 30 to 50 % lower pressure drop than the previous filter element generation. 
The work also laid the foundations for new computer software. The modules PleatGeo and PleatDict 
for ITWM's GeoDict Software are tailor-made and easy-to-use for the simulation and design of pleated filters.

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Last modified: Fri Oct 15 11:24:15 W. Europe Standard 2010