The control device 9 includes an evaluation unit 15 which determines {HEAD ~ the flow Q} of {TAIL ~ the fluid} through the hollow body 3 with the aid of the electrical current I required for the excitation of the electromagnet 8 and emits this via an output unit 150 
The control device 9 includes an evaluation unit 15 which determines { HEAD ~ the flow Q } of { TAIL ~ the fluid } through the hollow body 3 with the aid of the electrical current I required for the excitation of the electromagnet 8 and emits this via an output unit 150
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH