Electromagnetic flow meter for conductive fluids having matched magnetic and electrical systems

Claim 2

An electromagnetic flow meter for measuring the flow of an electrically conductive fluid through a pipe comprising, at least one electrical current-carrying coil mounted outwardly of the pipe bore for generating a magnetic field transverse to the direction of fluid flow, a plurality of electrodes mounted in the pipe opposite one another for producing an electrical signal of magnitude proportional to the velocity of the fluid flow through an electrode plane transverse to said flow direction and including said electrodes, the shape and dimensions of said coil and the shape and dimensions of said electrodes being selected to satisfy at each point in said electrode plane the equation (WyBxWxBy) K; wherein K is of substantially constant value and wherein the indices x and y represent mutually orthogonal vector components directed substantially parallel to an axis passing through said electrodes and substantially parallel to the direction of the magnetic field, respectively, of a weighting factor W and of a magnetic field density B.

Claim 3

An electromagnetic flow meter according to claim 1, wherein the shapes and dimensions of both said electrodes and said coil is chosen so that the value of the factor (Wy Bx) is as small as possible.

Claim 4

A flow meter according to claim 1 which comprises two current-carrying coils mounted opposite each other exteriorly of said pipe for generating said magnetic field.

Claim 5

A flow meter as claimed in claim 3 wherein said pipe has a circular cross section and wherein each said electrode comprises an arcuate sector conforming to an interior wall portion of said pipe.

Claim 6

A flow meter as claimed in claim 4 wherein said pipe has a circular cross section and wherein each said electrode comprises an arcuate sector conforming to an interior wall portion of said pipe, the interior surface dimension of said sector along the arc of curvature thereof being proportional to the internal radius of said pipe.

Claim 7

A flow meter as claimed in claim 3 wherein said pipe has a circular cross section and wherein each said electrode comprises an arcuate sector conforming to an interior wall portion of said pipe; each said sector having an arc of curvature substantially equal to the internal radius of said pipe, and further wherein said coils comprise a matched pair of coils of rectangular configuration.

Claim 8

A flow meter according to claim 1, wherein each of said electrodes comprises an array of discrete metallic elements mounted adjacent one another and electrically connected in parallel to an electrode output terminal.

Claim 9

The electromagnetic flow meter as claimed in claim 1, which further comprises, a source of time-varying signal coupled to said coils, the frequency of said signal being different than 60Hz., and means coupled to the signal source and synchronized to the frequency of said signal for synchronously receiving the signal output of said electrodes.

Claim 10

An electromagnetic flow meter for measuring the flow of an electrically conductive fluid through a pipe comprising, a pair of electrical current-carrying coils of regular geometrical shape mounted opposite one another outwardly of the pipe bore for generating a magnetic field transverse to the direction of fluid flow, a pair of electrodes mounted on the internal wall of said pipe opposite one another and defining therebetween an electrode plane which includes said magnetic field, said electrodes producing an electrical signal of magnitude proportional to the velocity of the fluid flow through said electrode plane, the interior surfaces of said electrodes having at least one dimension greater than the respective distances from the geometrical center of said pipe to said electrode surfaces, the dimensions of said coils being such as to follow the equation (WyBx-WxBy) K at each point in said electrode plane; wherein K is of substantially constant value, and wherein the indices x and y represent mutually orthogonal vector components oriented substantially parallel to an axis intersecting opposed ones of said electrodes and substantially parallel to the direction of the magnetic field, respectively, of a weighting factor W and of a magnetic field B.

Claim 11

An electromagnetic flow meter for measuring the flow of an electrically conductive fluid through a pipe comprising, a pair of electrical current-carrying coils of regular geometrical shape mounted opposite one another outwardly of the pipe bore for generating a magnetic field transverse to the direction of fluid flow, a pair of electrodes mounted on the internal wall of said pipe opposite one another and defining therebetween an electrode plane which includes said magnetic field, said electrodes producing an electrical signal of magnitude proportional to the velocity of the fluid flow through said electrode plane, the interior surfaces of said electrodes having at least one dimension greater than the respective distances from the geometrical center of said pipe to said electrode surfaces, the dimensions of said coils being such as to follow the equation (WyBx-WxBy) K at each point in said electrode plane; wherein K is of substantially constant value, and wherein the indices x and y represent mutually orthogonal vector components oriented substantially parallel to an axis intersecting opposed ones of said electrodes and substantially parallel to the direction of the magnetic field, respectively, of a weighting factor W and of a magnetic field B.

Claim 12

The flow meter as claimed in claim 9 wherein said one dimension is the electrode dimension parallel to the direction of fluid flow.

Claim 13

The flow meter as claimed in claim 9 wherein said pipe has a circular cross section and wherein said interior electrode surfaces are concave sectors located equal distances from the center of said pipe.

Claim 14

The flow meter as claimed in claim 9 wherein said electrode surfaces are of overall rectangular shape with the largest dimension thereof parallel to the direction of fluid flow.

Claim 15

The flow meter as claimed in claim 12 wherein said coils are of flat rectangular shape.

Claim 16

The flow meter as claimed in claim 9 wherein one of said electrodes is comprised of plural juxtaposed electrically conductive elements, and electrical circuit means for connecting the elements in parallel to a common electrode output terminal.

Claim 17

The flow meter as claimed in claim 14 wherein each of said elements comprises a point electrode.

Claim 18

The flow meter as claimed in claim 14 wherein each of said elements comprises an elongated electrically conductive strip.