US 6,476,619 B1 · METHOD AND DEVICE FOR HIGHLY ACCURATE, HIGH SPEED, REAL TIME, CONTINUOUS OR STATIONARY, IN-LINE, NON-INVASIVE, THREE DIMENSIONAL, MULTI-SLICE AND CALCULATIONS OF HOMOGENEOUS OR NON-HOMOGENEOUS FIBROUS YARN, SLIVERS, OR PAD MATERIAL

Abstract

A method for highly accurate, high speed, multi-slice density and moisture content measurements and calculations of homogeneous or non-homogeneous fibrous material, using a microwave resonator device and computer algorithms. The device is comprised of a cylindrical microwave resonator, including two cutoff waveguides, internal corrective pieces, a teflon tube, signal input and output ports, alternative microwave sources, alternative signal receivers, temperature sensor and optional moisture sensor, and computerized processing and display units. The method comprises passing fibrous material, located in-line of a production process, through the resonator, wherein the fibrous material is scanned with a sweeping range of microwave frequencies, in a continuous, real time, and multi-slice mode. The presence of the fibrous material causes resonance frequency shifts and changes in resonator quality, which are proportional to, and used in calculations of, material density and moisture content, respectively. Calculations of material density (and moisture content) are based on evaluation of density and moisture content arrays (of time samples), which are functions of resonator frequency shift and quality data, empirically determined density, moisture content, and structurally dependent correlation functions, and material temperature. Improved accuracy in values of density is obtained by compensating for moisture content. Density and moisture content values are used for real time quality control feedback of process parameters, including fiber density, moisture content, temperature, and incoming feed rate.

Claims40

Dependent claims

A method for continuously determining the density of a fibrous material, comprising the steps of:

(a) continuously guiding the fibrous material through and parallel to height of a cylindrical microwave resonator having a microwave resonance frequency, said cylindrical microwave resonator includes:
(i) an electrically conductive housing defining a cylindrical cavity having an input end and an output end;
(ii) a plastic cylindrical tube spanning inside said cylindrical cavity from said input end to said output end, wherein ratio of length of said cylindrical cavity to length of said plastic cylindrical tube is about one, and wherein ratio of diameter of said cylindrical cavity to diameter of said plastic cylindrical tube is between about two and three to one, for said continuously guiding the fibrous material through and parallel to height of said cylindrical microwave resonator and for preventing contamination by residual fibrous material inside said cylindrical cavity;
and
(iii) a mechanism for measuring a shift in said resonance frequency caused by a presence of the fibrous material inside said cylindrical cavity;
(b) measuring said shift in said resonance frequency caused by said presence of the fibrous material inside said cylindrical cavity;
and
(c) inferring the density of the fibrous material from said shift.

5 more elements

A method for continuously determining the density of a fibrous material, comprising the steps of:

(a) continuously guiding the fibrous material through and parallel to height of a cylindrical microwave resonator having a microwave resonance frequency, said cylindrical microwave resonator includes:
(i) an electrically conductive housing defining a cylindrical cavity having two substantially identical microwave resonance frequencies with respect to two degenerate modes of microwave radiation, said cylindrical cavity having an input end and an output end;
(ii) a mechanism for separating degeneracy of said two degenerate modes, so that said cylindrical cavity has two separate microwave resonance frequencies with respect to said two degenerate modes, said mechanism for said separating said degeneracy is at least two pieces of metal located entirely inside, attached to and internally protruding from sides of one end of said cylindrical cavity, whereby said metal pieces cause a decrease in said microwave resonance frequency of one of said two degenerate modes with smaller amplitude of said microwave radiation;
and
(iii) a mechanism for measuring a shift in one of said separate microwave resonance frequencies caused by a presence of the fibrous material inside said cylindrical cavity;
(b) measuring said shift in said one of said separate resonance frequencies caused by said presence of the fibrous material inside said cylindrical cavity;
and
(c) inferring the density of the fibrous material from said shift.

5 more elements

A device for continuously determining the density of a fibrous material, comprising:

(a) a cylindrical microwave resonator having a microwave resonance frequency, for continuously guiding the fibrous material through and parallel to height of said cylindrical microwave resonator, said cylindrical microwave resonator includes:
(i) an electrically conductive housing defining a cylindrical cavity having two substantially identical microwave resonance frequencies with respect to two degenerate modes of microwave radiation, said cylindrical cavity having an input end and an output end;
and
(ii) a mechanism for separating degeneracy of said two degenerate modes, so that said cylindrical cavity has two separate microwave resonance frequencies with respect to said two degenerate modes, said mechanism for said separating said degeneracy is at least two pieces of metal located entirely inside, attached to and internally protruding from sides of one end of said cylindrical cavity, whereby said metal pieces cause a decrease in said microwave resonance frequency of one of said two degenerate modes with smaller amplitude of said microwave radiation;
and
(b) a mechanism for measuring a shift in one of said separate microwave resonance frequencies caused by a presence of the fibrous material inside said cylindrical cavity;
and
(c) a mechanism for generating microwave radiation.

5 more elements

Dependencies are inferred from the claim text.

Method and device for highly accurate, high speed, real time, continuous or stationary, in-line, non-invasive, three dimensional, multi-slice and calculations of homogeneous or non-homogeneous fibrous yarn, slivers, or pad material

Life of this patent

Method and device for highly accurate, high speed, real time, continuous or stationary, in-line, non-invasive, three dimensional, multi-slice and calculations of homogeneous or non-homogeneous fibrous yarn, slivers, or pad material

Life of this patent

Abstract

Claims40