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Development of long-term stable filters with low pressure loss based on electrically conductive tufted structures for use in room air purifiers (PureAir)

Due to increasing air pollution and events such as the ongoing COVID pandemic, the need to improve indoor air quality through air filtration is steadily increasing. Currently, the main filters used for filtration are electret filters, which are characterised by a high separation rate combined with a low pressure loss. The filters lose their non-regenerative charge with increasing service life, which causes the filter effect to decrease. In addition, the filters cannot be cleaned, so they must be replaced regularly.

The aim of the project is to develop filter structures that have a constantly high filtration effect due to a permanent charge and can be cleaned.

The approach in this project is to develop a 3D textile structure with fibres arranged parallel to the direction of air flow. Insulating as well as electrically conductive yarns are incorporated into this 3D structure so that islands with differently charged electrical potentials can be created by applying a voltage in the surface. Among other things, the effect in relation to the proportions of conductive and non-conductive fibres and their arrangement in the surface is investigated. The tufting technique is a suitable manufacturing process, in which parameters such as the pile density in the longitudinal and transverse directions, pile height or offset pattern can be efficiently varied. With bipolar charging, the separation efficiency of the filter can be further increased while maintaining a low pressure loss. By applying a permanent voltage to the conductive material, the electrostatic separation in the filter is permanently maintained. The functional relationships between charge fields, tuft column and reciprocal charging are being analysed. Parallel to this, the concept development for the optimal cleaning process of the filters and the development of several filter types, as well as a large-scale demonstrator, which will be installed and tested in a room air purifier, are taking place.

Fig. Left: Example of a tufting structure with conductive yarns - Fig. Right: Principle of a room air purifier with tufted filter

Funding program and project number

IGF 21783 N2


01.05.2021 – 30.04.2023


Project partners and/or other research institutes

FE1: IUTA Institut für Energie- und Umwelttechnik e.V.
FE2: TFI Institut für Bodensysteme an der RWTH Aachen e.V.

Projektbegleitender Ausschuss:

  • Beurer GmbH
  • EMW Filtertechnik GmbH
  • Fiberlane GmbH & Co. KG
  • FILTEC W. Hermanns GmbH
  • getair GmbH
  • Hauser Umwelt-Service GmbH
  • Lydall Gutsche GmbH & Co. KG
  • Miele & Cie. KG
  • Morton Extrusionstechnik GmbH
  • Philips Consumer Lifestyle B.V.
  • Schöpp-Sportboden GmbH
  • Topas
  • TROX GmbH
  • TSI GmbH
  • Venta Luftwäscher GmbH


The IGF project “Development of long-term stable filters with low pressure loss based on electrically conductive tufted structures for use in room air cleaners” (PureAir 21783 N2) of the Research Association Forschungskuratorium Textil e.V., Reinhardtstraße 14 16, 10117 Berlin is funded by the Federal Ministry for Economic Affairs and Climate Action via the AiF within the framework of the programme for the promotion of joint industrial research and development (IGF) on the basis of a resolution of the German Bundestag.