Abstract: This publication discloses an electrostatic filter construction, which includes electrodes connected to a first electrical potential, second electrodes, which are electrically insulated from the first electrodes, and an insulating material acting as a particle filter, which is located between the first and the second electrodes. According to the invention, in both of the electrodes the electrode material used is a material, such as activated carbon, which is permeable to a gas and which filters the gas, and which has a low electrical conductivity, and both electrodes are located essentially parallel to the direction of the airflow.

Abstract: The present invention concerns an arrangement for cleaning ducts and chimneys, such as air conditioning ducts. The arrangement comprises a guide wire cable having a cleaning end and a feed end, a brush or some other tool being connected to the cleaning end of the guide wire cable, and a drive unit connected to the feed end of the guide wire cable, the arrangement further comprising transmission means for moving the brush by means of the drive unit. According to the invention the drive unit comprises a hydraulic pump, the transmission means are provided by hydraulic pipes arranged inside the guide wire cable, and the primary drive unit for the brush being a hydraulic motor connected to the cleaning end of the guide wire cable.