Laboratory exhaust cabinet variable air volume adjusting device

The utility model discloses a laboratory exhaust cabinet variable air volume adjusting device which comprises an exhaust cabinet, a window installed on the exhaust cabinet, an exhaust pipe arranged atthe top end of the exhaust cabinet, a transmission assembly and a Venturi valve arranged between the exhaust cabinet and the exhaust pipe. The transmission assembly comprises a synchronous rod, a synchronous belt arranged on the synchronous rod, a gearbox arranged on one side of the synchronous rod, a telescopic rod arranged on the gearbox and a lever connected with the telescopic rod. The Venturi valve comprises a valve body shell and a valve element assembly arranged in the valve body shell. One end of the synchronous belt is connected with a counterweight plate, and the other end of the synchronous belt is connected with the window; the gearbox is connected with the synchronous rod through a belt pulley assembly, and the lever is connected with the valve element assembly. The linkage structure can quickly chan