Method and apparatus for measuring flow in a pipe or conduit

An apparatus for measuring the velocity of flow in a pipe of a material having an adequate population of a selected element, comprising:

• (a) magnet means for forming a magnetic field perpendicular to the flow of the element of interest in the pipe, the field having a gradient in the direction of flow;
• (b) coil means forming a field at right angles to the magnetic field formed by said magnet means;
• (c) transmitter means connected to said coil, said transmitter means being adapted to form and apply to said coil means a signal having a frequency related to a first magnetic field intensity to accomplish a resonant relationship between the magnetic field transmitted signal, and the element of interest;
• (d) receiver means for detecting pulse echo signals from the element of interest flowing through said coil means, said receiver means forming a detected signal encoding the flow of the element of interest;
• (e) measuring means for measuring the detected signal and indicating flow velocity of the element of interest;
• and
• (f) means for operating said transmitter means to form a pair of spaced transmitted pulses, and wherein said receiver means is operated to receive echoes from the element of interest.

A method of determining flow velocity of an element of interest moving along a flow path comprising the steps of:

• (a) forming a magnetic field across the flow path, the field having a specified field strength and changing value along the path to create a gradient in the field;
• (b) forming first and second RF pulse bursts separated by a period of time for transmission into the flow path and at right angles to the magnetic field to initiate resonant interaction with the element of interest in timed sequence to enable the element of interest to move to a different magnetic intensity;
• (c) receiving first and second echo pulses after transmission of the pulse bursts;
• and
• (d) measuring the echo pulses for a velocity dependent change resulting from flow of the element of interest.

An apparatus for measuring the velocity of flow in a pipe of a material having an adequate population of a selected element comprising:

• (a) magnet means for forming a magnetic field perpendicular to the flow of the element of interest in the pipe, the field having a gradient in the direction of flow;
• (b) coil means forming a field at right angles to the magnetic field formed by said magnet means;
• (c) transmitter means connected to said coil, said transmitter means being adapted to form and apply to said coil means a signal having a frequency related to a first magnetic field intensity to accomplish a resonant relationship between the magnetic field transmitted signal, and the element of interest;
• (d) receiver means for detecting magnetic resonance signals from the element of interest flowing through said coil means, said receiver means forming an output signal of detected signals;
• (e) detector means connected to said receiver means for measuring the change in the detected signals from said receiver means and indicating flow velocity of the elemnt of interest as indicated by the change in the detected signals, the detected signals having a specified frequency spectrum and amplitude range;
• and
• (f) frequency responsive means for detecting amplitude distribution as a function of the specified frequency spectrum to indicate flow velocity and flow density profile of the element of interest.