The mass flow meter shows a negative value
Thread Content
Please, experts, explain it to us
If a check valve is not installed in the appropriate position during the installation of the mass flow meter, backflow can occur, which can lead to the phenomenon you are observing. Is there a check valve installed in front of your mass flow meter? Zero drift could also be the cause; close both valves to prevent the fluid from moving, and then perform a zero calibration
First, check whether the pressure at the outlet of each gas cylinder is the same; when three flow meters are connected in series, if the pressure of the gas exiting the cylinders differs, the gas with higher pressure will push against the outlet of the flow meter with lower pressure, and in some cases this can even result in a negative value being displayed by the flow meter. It is recommended to install a one-way valve behind each flow meter.