A flowmeter comprises a lower valve body (1), a throttle assembly, a flow tube assembly, an upper valve body (2), and a pressure fluctuation suppression assembly. An air inlet, an air outlet and an air flow channel connecting the air inlet and the air outlet are arranged in the lower valve body (1) a throttle assembly for adjusting the degree of opening of the air flow channel in the lower valve body (1) is further disposed on the lower valve body (1). The flow tube assembly comprises a flow tube (3), an upper base (4), a lower base (5), and a float (6) a vent hole is provided on each of axial centers of the upper base (4) and the lower base (5) the lower base (5) is arranged at the air outlet of the lower valve body (1) a vertical air flow passage and a horizontal air flow passage are arranged in the upper valve body (2) the upper base (4) is arranged at an air inlet of the vertical air flow passage in the upper valve body (2) the flow tube (3) is disposed between the upper base (4) and the lower base (5) through two ends thereof that are respectively sleeved on protruding portions of the upper base (4) and the lower base (5) the float (6) is disposed in the flow tube (3). The pressure fluctuation suppression assembly comprises a sealing gasket (7), and the sealing gasket (7) is disposed at an air outlet of the vertical air flow passage.
