1. One time feeding realize twice milling for fewer machines, less space and less driving power; 2. Aspiration devices to guide air flow properly for less dust; 3. One motor to drive two pairs of rolls simultaneously; 4. Suitable to gentle grinding of modern flour milling industry for less crushed bran, lower grinding temperature and higher flour quality; 5. Sensors are arranged between upper and lower rollers to prevent blocking; 6. Different material channels are isolated from each other, with good sealing performance to prevent material channeling.