Magnetic-inductive flowmeter

摘要

The invention relates to a magnetic-inductive flowmeter to which are assigned measuring devices for the detection and optionally also for the signalling of the boundary conditions of "measuring tube empty" or "overflow". In this connection, the capacitance Cw on the electrodes E1, E2, which varies strongly (factor about 50) between the conditions of "empty" and "full", is used as parameter for empty-tube detection or the presence of an over-driving of the measuring amplifier "on to the stops". The presence of overdriving of the measuring amplifier is likewise used as parameter for the overflow detection. These parameters are logically coupled for further decision-making using measuring-phase-specific criteria, in order to obtain a statement as to which of the conditions of "measuring tube empty" or "overflow" exists. The type of the boundary condition established is indicated optically on the flowmeter. External signalling to a central location is possible. The flowmeter according to the invention is so configured that the measuring device provided for the flow can also be used to determine the boundary conditions. <IMAGE>