Calibrating device for heavy caliber gas flow

The utility model relates to a calibrating device for heavy caliber gas flow. The technical scheme includes that the calibrating device comprises a control and measured data processing system mounted on a meter clamping platform, and a stagnation container, sound velocity nozzles, a backpressure container and an air extractor which are sequentially communicated, and a plurality of connecting pipes with different pipe diameters for communicating a flow measuring device to be calibrated are communicated with the stagnation container. The calibrating device is characterized in that the at least ten sound velocity nozzles are arranged parallelly and two ends of each sound velocity nozzle are communicated with the stagnation container and the backpressure container, the at least ten sound velocity nozzles are connected to a pipeline provided with valves, so that the parallel connection mode of the sound velocity nozzles can be adjusted. The meter clamping platform, the stagnation container, the backpressure container and the connecting pipe are made of stainless steel. The calibrating device can effectively satisfy calibration requirements for heavy caliber flow measuring devices and has the advantages of being simple in structure, stable in performance, high in accuracy, long in calibrating period and convenient to maintain.