Importance of the chip impregnation stage is widely recognised in chemical pulping processes. However, there is limited amount of direct data on mass transfer during the impregnation stage. Most methods used for studying the liquid penetration process were based on indirect approaches. A new laboratory impregnator with a special weight sensor was developed, which allowed the direct measurements of the chip weight during impregnation process. First part of the research included testing of the system under various process conditions and method development. Experiments with water showed that the impregnator could be successfully used in studying the effect of different factors on the liquid penetration into wood chips. The new system can also be used as a tool to investigate different “penetration aid” techniques, including presteaming, evacuation, addition of surfactant, and various mechanical and biotreatments of wood chips.