Filter manufacturing apparatus

A filter manufacturing apparatus comprising:

• a feed path to continuously feed a filter material along a longitudinal transport direction;
• a forming device connected to a terminating end of the feed path to form the filter material into a rod-shaped continuous filter body and deliver the continuous filter body, the forming device including:
• a tubular element with through hole allowing the filter material to pass therethrough to form the filter material into the continuous filter body;
• a heat source to heat the filter material passing in the tubular element;
• a diameter measuring device positioned at an outlet of the forming device to measure a diameter of the continuous filter body;
• a pressurized fluid generator to blow pressurized fluid towards the filter material to transport the filter material into the tubular element;
• a control unit configured to receive signals from the diameter measuring device relative to the diameter of the continuous filter body and to send signals to the pressurized fluid generator to vary pressurized fluid production or to a display in order to visualize the measurement and configured to compare a signal relative of measured diameter to a reference diameter and to change a parameter in the pressurized fluid generator to increase fluid pressure in case the measured diameter is bigger than the reference diameter of more than a given amount.