Magnetic-inductive flow meter

A magnetic-inductive flow meter for detecting a flow-rate-dependent measurement variable of a flowable medium, comprising:

• a measuring tube for guiding the medium;
• a magnetic-field-generating device for generating a magnetic field that penetrates the measuring tube;
• at least one measuring electrode for tapping a measurement voltage induced in the medium,
• wherein the measuring electrode is arranged in a measuring electrode opening in the measuring tube,
• wherein the measuring electrode has a measuring electrode head which is configured to come into contact with the medium;
• a reference electrode for connecting the medium to a reference potential,
• wherein the reference electrode is arranged in a reference electrode opening in the measuring tube,
• wherein the reference electrode has a reference electrode head which is configured to come into contact with the medium,
• wherein the reference electrode head has, in a cross-sectional plane A of the measuring tube intersecting the reference electrode and the at least one measuring electrode, a reference electrode diameter DRE,
• wherein the measuring electrode head has, in the cross-sectional plane A, a measuring electrode diameter DME,
• such that
• the reference electrode diameter DRE is at least 10% the measuring electrode diameter DME.

A magnetic-inductive flow meter for detecting a flow-rate-dependent measurement variable of a flowable medium, comprising:

• a measuring tube for guiding the medium;
• a magnetic-field-generating device for generating a magnetic field that penetrates the measuring tube;
• at least one measuring electrode for tapping a measurement voltage induced in the medium,
• wherein the measuring electrode is arranged in a measuring electrode opening in the measuring tube,
• wherein the measuring electrode has a measuring electrode head which is configured to come into contact with the medium;
• a fill-level monitoring electrode,
• wherein the fill-level monitoring electrode is arranged in a fill-level monitoring electrode opening of the measuring tube,
• wherein the fill-level monitoring electrode has a fill-level monitoring electrode head,
• wherein the fill-level monitoring electrode head is configured to come into contact with the medium,
• wherein the fill-level monitoring electrode head has, in a cross-sectional plane A of the measuring tube intersecting the fill-level monitoring electrode and the at least one measuring electrode, a fill-level monitoring electrode diameter DFÜ,
• wherein the measuring electrode head has, in the cross-sectional plane A, a measuring electrode diameter DME,
• such that the fill-level monitoring electrode diameter DFÜ is at least 10% the measuring electrode diameter DME.

The magnetic-inductive flow meter according to 16,

• wherein the measuring tube has a measuring tube diameter DMR,
• wherein the measuring tube diameter DMR is greater than the fill-level monitoring electrode diameter DFÜ,
• wherein, for a ratio r=DFÜ/DMR, the following applies:
• 0.05≤R≤0.25.