Anti-blocking blowback system of interface level instrument

The utility model belongs to the technical field of interface position instruments, and particularly relates to an anti-blocking blowback system of an interface position instrument, which comprises an air source, a nitrogen ball valve, a filtering pressure reducing valve, a throttling valve, a rotor flow meter, a differential pressure transmitter, a pressure taking ball valve and an air blowing pipe, and a two-position three-way electromagnetic valve is arranged on a connecting pipeline between the differential pressure transmitter and the pressure taking ball valve. Two inlets of the two-position three-way electromagnetic valve are respectively connected with a differential pressure transmitter and an air source through pipelines, an outlet of the two-position three-way electromagnetic valve is connected with a pressure taking ball valve through a pipeline, and the two-position three-way electromagnetic valve is electrically connected with a field bus control system (FCS); the device is simple in structure,