Mass flowmeter for gases, uses vibrating spool piston inside measuring cylinder and has motorized adjustment which varies volume of cylinder to suit flow range

摘要

The mass of gas flowing through the measuring cylinder (10) has a damping effect on the oscillation of a vibrating spool sensor. The sensor is mounted on a piston (20) which can be moved in or out of the cylinder (10) by a motorized adjustment unit (30). The electronic controller (50) is fed with outputs from the adjustment unit and pressure sensors (40). The volume of the measuring chamber (13) is varied to suit the expected flow range.