Pressure pulse impregnation process using high voltage technology - Generation of electrohydraulic discharges to improve treatability of softwoods with impregnating liquid

Inhalt:
The subject of these investigations is the generation of pressure pulses in liquids either by an electrical pulse breakdown of a spark gap arrangement or by electromagnetic actuators and impressed surge currents is a high-voltage technology whose applicability to the impregnation of softwoods. Softwoods are the most important timbers in Germany due to their fast growth performance, good mechanical properties and easy cultivability as well as high availability. In the light of possible future industrial utilization e.g. timber impregnating treatment an autoclave with suitable high-voltage and measuring bushings was developed, in which pressure pulses of different amplitudes and time courses can be generated in the impregnation solution. The penetration depths of the fir wood test samples were measured. In our investigations we found depending on the intensity of the incident shock wave, on the distance to the shock wave generating device, as well as on the orientation of sample arrangement, we found the tissue structure either heavily disintegrated or hardly affected at all or the shock wave shows no effect. An improvement on impregnation could not be found.