Small bioreactor

The utility model discloses a small bioreactor which comprises a tank body, an air inlet is arranged on the tank body, the air inlet is connected with an air outlet of an air filter, an air inlet of the air filter is connected with an outlet of a rotor flow meter, and an inlet of the rotor flow meter is respectively connected with a gas mass flow meter and a valve through a tee joint. And the gas mass flow meter and the gas inlet of the valve are connected with an air pipeline. In order to deal with power failure, facilitate maintenance and better guarantee sterility, the air bypass branch is arranged between the air filter and the air pipeline, meanwhile, the rotor flow meter is additionally arranged at the air outlet end of the gas mass flow meter, and the air inlet end of the rotor flow meter is connected with the air pipeline through the air bypass branch. In a normal working condition, air passes through the gas mass flow meter, the rotor flow meter and the air filter in sequence to reach the small biore