Apparatus to obtain flow rates (melt index) in plastics via fixed frequency, pulsed NMR

Claim 1

In a nuclear magnetic resonance system for measuring flow rates in plastics comprising: (a1) means for accessing and then (a2) removing successive samples of plastic material from an industrial process and then (a3) placing them in a sample measuring region, (b) means for applying a base magnetic field to said region to effect precession of nuclei of the samples of material therein, (c) means for applying a local excitation pulse of energy to said region to modify the precession, (d) said means (c) including transmit-receive antenna coil means and means for translating a received relaxation signal detected at the coil means in the form of a free induction decay, said relaxation signal being based on free induction decay of the sample material nuclei, (e) means for digitizing the free induction decay and analyzing the free induction decay into component equations, (f) means for further analyzing the component equations comprising means utilizing an iteration technique for converting said digitized version of said free induction decay into the component equations of said decay and establishing said zero intercepts and time parameters of said equations corresponding to flow rates in plastics, by forming a calibration relationship between the component equation parameters and known flow rates of known plastics, including MI and FRR for polyethylene and MF for polypropylene, means to input a sample temperature set point, means, responsive to said set point, to maintain said sample temperature at about said set point throughout said sampling and nuclear magnetic resonance measuring, and then discarding the samples from said region.

Claim 9

A method for measuring flow rates in plastics in industrial processes utilizing magnetic resonance comprising the steps of: accessing and removing successive samples of plastic material from an industrial process placing said samples in a sample measuring region, applying a base magnetic field to said region to effect precession of nuclei of the samples of material therein, applying a local excitation pulse of energy to said region to modify the precession, receiving and translating a free induction decay signal, said free induction decay signal generated by the relaxation of the sample material nuclei after the end of said local excitation pulse, digitizing and analyzinq the free induction decay signal into component equations of the free induction decay signal, said analyzing comprising: applying an iteration technique to the digitized free induction decay signal wherein said digitized signal is separated into a plurality of component curves. determining the equations of the decay curve components in digital form and parameters defining the component equations, including zero intercepts and time Parameters of said equations forming calibration relationships between zero intercepts and time parameters of component equations to known flow rates in known plastics, and relating the zero intercepts and time parameters of the sample, to flow rates in plastics, including MI and FRR for polyethylene and MF for polypropylene, and measuring the temperature of said industrial process material heating a volume of air, responsive to said measured temperature, circulating said heated air around said .sample measuring region, wherein said sample maintains about constant temperature throughout said sampling and nuclear magnetic resonance measuring, and discarding said sample from said region.

Claim 10

A method for measuring flow rates in plastics in industrial processes utilizing magnetic resonance comprising the steps of: accessing and removing successive samples of plastic material from an industrial process placing said samples in a sample measuring region, applying a base magnetic field to said region to effect precession of nuclei of the samples of material therein, applying a local excitation pulse of energy to said region to modify the precession, receiving and translating a free induction decay signal, said free induction decay signal generated by the relaxation of the sample material nuclei after the end of said local excitation pulse, digitizing and analyzinq the free induction decay signal into component equations of the free induction decay signal, said analyzing comprising: applying an iteration technique to the digitized free induction decay signal wherein said digitized signal is separated into a plurality of component curves. determining the equations of the decay curve components in digital form and parameters defining the component equations, including zero intercepts and time Parameters of said equations forming calibration relationships between zero intercepts and time parameters of component equations to known flow rates in known plastics, and relating the zero intercepts and time parameters of the sample, to flow rates in plastics, including MI and FRR for polyethylene and MF for polypropylene, and measuring the temperature of said industrial process material heating a volume of air, responsive to said measured temperature, circulating said heated air around said .sample measuring region, wherein said sample maintains about constant temperature throughout said sampling and nuclear magnetic resonance measuring, and discarding said sample from said region.