Proton resonance volumetric flowmeter

Claim 2

A flowmeter for measuring the flow of a fluid through a conduit comprising: a first means for producing an unvarying magnetic field in said conduit; a second means for producing a pulsed magnetic field at a point in the fluid flowing through said conduit; said second means being mounted within the unvarying magnetic field produced by said first means and producing a magnetic field nonparallel to the field produced by said first means; said second means producing a perturbation in the fluid in the form of a precession of the proton magnetic moment about the direction of the unvarying field; third means producing a plurality of discrete signals, each signal having an amplitude proportional to the amplitude of the perturbation at each of a plurality of respective points; said plurality of points being spaced along the conduit in the direction of fluid flow and within the unvarying magnetic field; and fourth means for comparing the amplitudes produced by said third means and indicating the rate of fluid flow through the conduit.

Claim 3

A flowmeter as claimed in claim 1 in which said first means comprises a solenoid wound on said conduit and a source of power connected to said solenoid.

Claim 4

A flowmeter as claimed in claim 2 in which said second means comprises an electromagnetic coil and a power source connected to said electromagnetic coil.

Claim 5

A flowmeter as claimed in claim 1 in which said third means includes a first and second detection means mounted in spaced relation to each other along the direction of fluid flow through the conduit: said first and second detection means producing signals having voltage amplitudes proportional to the perturbations at the positions of the respective first and second detection means; and said fourth means includes a first voltage comparison means connected to receive the output of said first and second detection means, to compare the voltage amplitudes of the signals from the first and second detection means and producing an output indicative of the rate of flow in the conduit.

Claim 6

A flowmeter as claimed in claim 4 in which said first detection means is a coil: said second detection means is a coil; a first amplifier connected to receive the output of said first coil; a second amplifier connected to receive the output of said second coil; a first band-pass filter connected to receive the output of said first amplifier and tuned to the signal frequency associated with the proton spin of some preselected material; a second band-pass filter connected to receive the output of said second amplifier and tuned to the signal frequency of said first band-pass filter; a first detector connected to receive the output of said first band-pass filter and producing a voltage amplitude proportional to the amplitude of the perturbation of the proton spin at the position of said first coil; a second detector connected to receive the output of said second band-pass filter and producing a signal having a voltage amplitude proportional to the amplitude of the perturbation in the proton spin at the position of said second coil; and a first voltage comparison means connected to receive the outputs of said first and second detectors and producing an output indicative of the rate of flow of the fluid in said conduit.

Claim 7

A flowmeter as claimed in claim 4 in which said fourth means includes means for sensing the temperature of said fluid and producing an electrical signal proportional to such temperature and a second voltage comparison means connected to receive the output of the first comparison means and the output of said temperature sensing means to produce a temperature corrected measurement of the flow rate.

Claim 8

A flowmeter as claimed in claim 4 in which said first voltage comparison means includes first and second logarithmic amplifiers: said first logarithmic amplifier connected to receive the output of said first detector; said second logarithmic amplifier connected to receive the output of said second detector; a summing amplifier; and said summing amplifier connected to receive the output of said first logarithmic amplifier and the output of said second logarithmic amplifier whereby the signals received by said summing means are the logarithm of the signal amplitude detected by said first and second detection means.

Claim 9

A flowmeter as claimed in claim 1 in which said first means is a magnet mounted to establish a magnetic field longitudinally of a section of said conduit.

Claim 10

A device as claimed in claim 1 in which said second means is mounted to produce a magnetic field at right angles to the ambient field produced by said first means.