axial exit port for which the flowmeter constant is almost zero in the reverse flow direction consequently a flowmeter with axial exit port will give erroneous reading if the fluid does not flow in one direction only while the flowmeter of this invention will give true average reading since in automotive application the fuel flow in one direction is always dominant it is not necessary to use the flow direction sensing means in fig3 and 5 the same numbers are used as in fig1 and 2 to designate the various elements of the invention fig3 shows schematically the details of the photoelectric sensing means passing of the opaque ball 15 between source of light 22 and phototransistor 23 decreases its conductivity thus causing voltage increase on output terminal 27 which is utilized to activate a readout device 28 is current limited resistor 29 is battery instead of the opaque ball a reflecting ball could be used in which case both the light source and the photoelectric element would be located on the same side fig4 shows inductive pickup means the ball is designated in this case with number 29 to indicate that it is of different material than the ball 15 in fig3 the inductive pickup 30 is of standard construction as known to all.