A measuring device has a flowmeter, an inlet tube and an outlet tube. The flowmeter has a measuring tube that is connected to the inlet tube and to the outlet tube. To provide a measuring device that allows for measurements using a flowmeter, in particular of the liquid components of medium in the measuring tube, independent of whether the medium is made to flow or is stagnant, wherein the measuring tube is completely filled at least with the liquid components of the medium when the medium is stagnant the inlet tube, the measuring tube and the outlet tube form a siphon, wherein the siphon is designed and aligned in respect to the vector of the gravitational field of the earth so that, when a medium initially flows through the siphon and then the flowing of the medium stops, the measuring tube is completely filled with the stagnant medium.