Mass flowmeter

A mass flowmeter for measuring a flux of a fluid comprising:

• a sensor tube including a first tube part for receiving the fluid and a second tube part for outputting the fluid;
• vibrating means for vibrating the first tube part at a first position and the second tube part at a second position in mutually opposite directions;
• displacement detecting means for detecting a displacement of the first tube part on an upstream side and on a downstream side of the first position and a displacement of the second tube part on an upstream side and on a downstream side of the second position;
• and
• measuring means for calculating the flux of the fluid based on a phase difference between a first sum of the displacements detected on the upstream side of the first position and on the upstream side of the second position and a second sum of the displacements detected on the downstream side of the first position and on the downstream side of the second position.