Device for measuring the mass flow or flow rate of an insulating liquid

Claim 2

A measuring device for measuring the mass flow of a liquid, comprising: first, second, third and fourth electrodes positioned in the path of said liquid flow, said first, second, third and fourth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction and being electrically connected to said second electrode; a voltage source coupled between said first electrode and said second, third and fourth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode, in the direction of the liquid flow; a display device coupled between said third and first electrodes for displaying said liquid mass flow; means coupled to said second, third and fourth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode; and electrical means coupled to said third electrode for adjusting said measuring device for a nil liquid flow.

Claim 3

A measuring device according to claim 1 wherein said electrical means comprises means for transmitting to said display device only the current corresponding to the direct flow sensed by said third electrode.

Claim 4

A measuring device according to claim 1 wherein said electrical means comprises means for shifting the level of the signal sent to said display device.

Claim 5

A measuring device for measuring the flow rate of a liquid, comprising: first, second, third and fourth electrodes positioned in the path of said liquid flow, said first, second, third and fourth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction and being electrically connected to said second electrode; a first voltage source coupled between said first electrode and said second, third and fourth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode, in the direction of the liquid flow; a display device coupled between said third and first electrodes for displaying said liquid flow rate; a second voltage source, said second voltage source having a constant voltage; means connected to said second voltage source and to a control input of said first voltage source for stabilizing the current supplied to said first electrode; and electrical means coupled to said third electrode for adjusting said measuring device for a nil liquid flow.

Claim 6

A measuring device for measuring the flow rate of a liquid, comprising: first, second, third and fourth electrodes positioned in the path of said liquid flow, said first, second, third and fourth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction and being electrically connected to said second electrode; a first voltage source coupled between said first electrode and said second, third and fourth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode, in the direction of the liquid flow; a display device coupled between said third and first electrodes for displaying said liquid flow rate; a second voltage source, said second voltage source having a constant voltage; means connected to said second voltage source and to a control input of said first voltage source for stabilizing the current supplied to said first electrode; and electrical means coupled to said third electrode for adjusting said measuring device for a nil liquid flow.

Claim 7

A measuring device according to claim 4, wherein said electrical means comprises means for transmitting to said display device only the current corresponding to the direct flow sensed by said third electrode.

Claim 8

A measuring device according to claim 4, wherein said electrical means comprises means for shifting the level of the signal sent to said display device.

Claim 9

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counterflow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode; and electrical means connected to said third and fifth electrodes for adjusting said measuring device for a nil liquid flow.

Claim 10

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counterflow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode; and electrical means connected to said third and fifth electrodes for adjusting said measuring device for a nil liquid flow.

Claim 11

A measuring device according to claim 7, wherein said electrical means comprises means for transmitting to said display device only the current corresponding to the direct flow sensed by said third and fifth electrodes.

Claim 12

A measuring device according to claim 8, wherein said electrical means comprises a diode.

Claim 13

A measuring device according to claim 7, wherein said electrical means comprises means for shifting the level of the signal sent to said display device.

Claim 14

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode, the minimum distance between said first and second electrodes and said first and fourth electrodes being determined by the breakdown voltage between said first and second electrodes and said first and fourth electrodes; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode.

Claim 15

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode, the minimum distance between said first and second electrodes and said first and fourth electrodes being determined by the breakdown voltage between said first and second electrodes and said first and fourth electrodes; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode.

Claim 16

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode, the minimum distance between said second and third electrodes and between said fourth and fifth electrodes being the distance for which the lines of force emanating from said first electrode traverse said second and fourth electrodes respectively, when said liquid is at rest, without quite reaching said third and fifth electrodes respectively; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode.

Claim 17

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode, the minimum distance between said second and third electrodes and between said fourth and fifth electrodes being the distance for which the lines of force emanating from said first electrode traverse said second and fourth electrodes respectively, when said liquid is at rest, without quite reaching said third and fifth electrodes respectively; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode.

Claim 18

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode, said electrodes being arranged within a measuring pipe and substantially perpendicular to the pipe axis, each electrode being a conductive grating occupying substantially the entire cross-sectional area of the pipe; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode.

Claim 19

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode, said electrodes being arranged within a measuring pipe and substantially perpendicular to the pipe axis, each electrode being a conductive grating occupying substantially the entire cross-sectional area of the pipe; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode.

Claim 20

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode, including means for stabilizing the ratio of the current supplied to said first electrode to the voltage of said voltage source.

Claim 21

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode, including means for stabilizing the ratio of the current supplied to said first electrode to the voltage of said voltage source.

Claim 22

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow, said display device being coupled to said fifth electrode through a phase inverter; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode.

Claim 23

A bi-directional measuring device for measuring the mass flow of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid mass flow, said display device being coupled to said fifth electrode through a phase inverter; and means coupled to said second, third, fourth and fifth electrodes and connected to a control input of said voltage source for stabilizing the current supplied to said first electrode.

Claim 24

A bi-directional measuring device for measuring the flow rate of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a first voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid flow rate; a second voltage source, said second voltage source having a constant voltage; and means connected to said second voltage source and to a control input of said first voltage source for stabilizing the current supplied to said first electrode.

Claim 25

A bi-directional measuring device for measuring the flow rate of a liquid, comprising: first, second, third, fourth and fifth electrodes positioned in the path of said liquid flow, said first, second, third, fourth and fifth electrodes being electrically isolated from each other, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a first voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said liquid flow rate; a second voltage source, said second voltage source having a constant voltage; and means connected to said second voltage source and to a control input of said first voltage source for stabilizing the current supplied to said first electrode.

Claim 26

A measuring device according to claim 16, wherein said third and fifth electrodes are coupled to electrical means for adjusting said measuring device for a nil liquid flow.

Claim 27

A measuring device according to claim 17, wherein said electrical means comprises means for transmitting to said display device only the current corresponding to the direct flow sensed by said third and fifth electrodes.

Claim 28

A measuring device according to claim 18, wherein said electrical means comprises a diode.

Claim 29

A measuring device according to claim 17, wherein said electrical means comprises means for shifting the level of the signal sent to said display device.

Claim 30

A measuring device according to claim 16, wherein the lower limit of the distance between said first and second electrodes and said first and fourth electrodes is determined by the breakdown voltage between said first and second electrodes and said first and fourth electrodes.

Claim 31

A measuring device according to claim 16, wherein the lower limit of the distance between said second and third electrodes and between said fourth and fifth electrodes is the distance for which the lines of force emanating from said first electrode traverse said second and fourth electrodes respectively, when the liquid is at rest, without quite reaching said third and fifth electrodes respectively.

Claim 32

A measuring device according to claim 16, wherein all the electrodes are arranged within a measuring pipe and are substantially perpendicular to the pipe axis, each electrode being a conductive grating occupying substantially the entire cross-sectional area of the pipe.

Claim 33

A measuring device according to claim 16, wherein said means connected to said control input of said first voltage source includes means for stabilizing the ratio of the current supplied to said first electrode to the voltage of said first voltage source.

Claim 34

A measuring device according to claim 16, wherein said fifth electrode is coupled to said display device through a phase inverter.

Claim 35

A bi-directional measuring device for measuring the mass flow or the flow rate of a liquid, comprising: first, second, third, fourth and fifth electrodes arranged within a measuring pipe substantially perpendicularly to the axis of the pipe, each electrode being a conductive grating occupying substantially the entire cross-sectional area of the measuring pipe, said five electrodes being electrically isolated from each other in said pipe, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a first voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said mass flow or said flow rate; a phase inverter coupled between said fifth electrode and said display device; a second voltage source, said second voltage source having constant voltage; inverter means, the output of said inverter means being connected to a control input of said first voltage source, a first input of said inverter means adapted for connection to means coupled to said second, third, fourth and fifth electrodes for stabilizing the current supplied to said first electrode, said display device displaying thereby said mass flow, a second input of said inverter means adapted for connection to said second voltage source for stabilizing the current supplied to said first electrode, said display device displaying thereby said flow rate; and electrical means coupled to said third and fifth electrodes for adjusting said measuring device for a nil flow, said electrical means comprising diode means for transmitting to said display device only the current corresponding to the direct flow sensed by said third and fifth electrodes respectively, said electrical means also comprising means for shifting the level of the signals sent to said display device.

Claim 36

A bi-directional measuring device for measuring the mass flow or the flow rate of a liquid, comprising: first, second, third, fourth and fifth electrodes arranged within a measuring pipe substantially perpendicularly to the axis of the pipe, each electrode being a conductive grating occupying substantially the entire cross-sectional area of the measuring pipe, said five electrodes being electrically isolated from each other in said pipe, said second electrode being spaced from said first electrode in the flow direction, said third electrode being spaced from said second electrode in the flow direction, said fourth electrode being spaced from said first electrode in the counter-flow direction, said fifth electrode being spaced from said fourth electrode in the counter-flow direction, said second and fourth electrodes being arranged symmetrically with respect to said first electrode, said third and fifth electrodes being arranged symmetrically with respect to said first electrode, said second electrode being electrically connected to said fourth electrode; a first voltage source coupled between said first electrode and said second, third, fourth and fifth electrodes for producing a corona discharge localized about said first electrode and for creating an electric field such that the ions produced by said first electrode move toward said second electrode in the flow direction and toward said fourth electrode in the counter-flow direction; a display device coupled between said third and fifth electrodes for displaying said mass flow or said flow rate; a phase inverter coupled between said fifth electrode and said display device; a second voltage source, said second voltage source having constant voltage; inverter means, the output of said inverter means being connected to a control input of said first voltage source, a first input of said inverter means adapted for connection to means coupled to said second, third, fourth and fifth electrodes for stabilizing the current supplied to said first electrode, said display device displaying thereby said mass flow, a second input of said inverter means adapted for connection to said second voltage source for stabilizing the current supplied to said first electrode, said display device displaying thereby said flow rate; and electrical means coupled to said third and fifth electrodes for adjusting said measuring device for a nil flow, said electrical means comprising diode means for transmitting to said display device only the current corresponding to the direct flow sensed by said third and fifth electrodes respectively, said electrical means also comprising means for shifting the level of the signals sent to said display device.