Flow limiting device with adjustable aperture

The utility model discloses a flow limiting device with an adjustable aperture. The flow limiting device comprises an upper seat, a main body, a rotating shaft, an eccentric rotating sleeve, a lower seat, a rotating motor and a connecting shaft, the upper seat, the main body and the lower seat form a cavity, and the main body is provided with an air inlet and an air outlet which are communicated with the cavity; the eccentric rotating sleeve is located in the cavity, an eccentric hole is formed in the eccentric rotating sleeve, a rotating shaft is connected to the eccentric hole, one end of the rotating shaft is connected to the lower base, the other end of the rotating shaft extends out of the upper base and is connected with the rotating motor through a connecting shaft, and the rotating shaft drives the eccentric rotating sleeve to do cam motion in the cavity through rotation of the rotating motor; sample gas enters the cavity from the gas inlet and then flows out from the gas outlet, and the eccentric rot