When the oil enters the device, it first enters the degassing filter through the inlet valve. The medium is filtered and enters the mass flow meter for measurement. Then it flows through the regulating valve and the outlet electric ball valve, and enters the downstream device. At the same time, there is a calibration circuit in the device, that is, a branch is set at both ends of the outlet electric ball valve after the mass flow meter, which is connected to the calibration inlet ball valve and the calibration outlet ball valve with DBB function, respectively, to achieve online calibration.

The mass flow meter measures the mass flow rate of a fluid through the vibration of two parallel measuring tubes based on the Coriolis force principle. Since the measuring tubes continuously vibrate at a certain resonance frequency, the vibration frequency changes with the density of the fluid, and the density output signal corresponding to the resonance frequency can be obtained, which is then transmitted to the flow computer.