A liquid extraction filter, more particularly a continuous-action, top-feed, vacuum drum filter includes a drum structure and filter elements, the filtration surface of which filter elements is formed of microporous hydrophilic material such that when filtering with a partial vacuum it is impervious to the surrounding air. To keep the efficiency of the driving-dynamics means nearly constant over the entire road-speed range of the vehicle, the servo drive is implemented as a variable torque assistance system, the degree of torque assistance being dependent on the road speed of the vehicle and on at least one variable of the driving-dynamics means that characterizes the correction angle. A second group of parting dimples defines the first false non-planar parting line. These outputs can be appended to data profiles of customers and prospects and can be utilized to support decisions involving prospecting, new account evaluation, and customer management across the lifecycle.