# US 12,000,798 B2 · Detection of structural variations in articles using acoustic resonance spectroscopy

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- Number: US 12,000,798 B2
- Document ID: US12000798B2
- Status: Granted
- Kind: B2
- Application number: 17/238,512
- Filed: 2021-04-23
- Published: 2021-10-28
- Granted: 2024-06-04
- Earliest claimed: 2020-04-24
- Assignees: AWE Technologies, LLC
- Applicants: AWE Technologies, LLC
- Inventors: Dipen N. Sinha
- Web page: https://patentgrep.com/patent/US12000798B2

## CPC

- G01N 29/12: by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)}
- G01M 3/24: using infrasonic, sonic or ultrasonic vibrations
- G01N 29/2418: {using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics (photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046)}
- G01N 29/348: {with frequency characteristics, e.g. single frequency signals, chirp signals (measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00)}
- G01N 29/42: by frequency filtering {or by tuning to resonant frequency}
- G01N 29/4436: {with a reference signal (amplitude comparison G01N29/48)}
- G01N 29/4454: {Signal recognition, e.g. specific values or portions, signal events, signatures}
- G01N 29/46: by spectral analysis, e.g. Fourier analysis {or wavelet analysis (spectral signal processing per se G06F17/14)}
- G01N 2291/014: Resonance or resonant frequency
- G01N 2291/044: Internal reflections (echoes), e.g. on walls or defects
- G01N 2291/045: External reflections, e.g. on reflectors
- G01N 2291/102: one emitter, one receiver
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR

## Abstract

An apparatus and method utilizing acoustic resonance spectroscopy applicable to any mechanical device or structure having internal or external components that need to be positioned away from a set point and then returned to the original position, such as a valve which is opened to pass fluids and subsequently closed, for noninvasively providing a measure of the deviation from the original position, and for classifying or grouping together objects that appear to be identical from the outside, but which may have slight external or internal differences, such as sealed containers filled with different fluids or materials, are described.

## Claims

### Claim 1

An apparatus for determining whether fluid is leaking through a valve seat when said valve is in a closed condition, comprising:
a valve comprising a valve seat, a disk or plug for forming a fluid seal with said seat, a stem for driving said disk or plug against said seat, and a valve body having an outside surface;
an acoustic transmitting transducer disposed in vibrational contact with the outside surface of said valve for generating vibrations in the valve body when excited by a chosen voltage signal;
an acoustic receiver disposed in vibrational contact with the outside surface of said valve for receiving vibrations induced in said valve body, and converting the received vibrations into electrical voltages;
a frequency sweep generator in electrical communication with said acoustic transmitting transducer, for generating chosen excitation voltage signals having frequencies within a selected frequency range thereon;
a narrow-band, band-pass tracking filter having a center frequency which tracks the frequencies within the selected frequency range generated by said frequency sweep generator, and having a chosen frequency bandwidth, for receiving electrical voltages from said acoustic receiver and filtering the electrical voltages; and
a microcontroller for controlling said frequency sweep generator and said band-pass tracking filter, for storing the filtered electrical voltages from said band-pass tracking filter, for generating at least two acoustic resonance spectra of said valve in its closed condition, and for comparing the at least two generated acoustic resonance spectra to determine whether there is a difference therebetween.

### Claim 2 (depends on 1)

The apparatus of claim 1, further comprising an amplifier for receiving the electrical voltages from said ultrasonic receiving transducer, and amplifying the electrical voltages.

### Claim 3 (depends on 1)

The apparatus of claim 1, further comprising a pressure sensor for determining fluid pressure in the region of said valve seat.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein said acoustic transmitting transducer and said acoustic receiver are not in physical contact with one another.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the frequency sweep from said frequency sweep generator is in either or both directions.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein said acoustic transmitting transducer comprises a piezoelectric transducer and said acoustic receiver is chosen from a piezoelectric transducer and a laser Doppler vibrometer.

### Claim 7

A method for determining whether fluid is leaking through a valve seat of a valve when said valve is in a closed condition, comprising:
generating vibrations having chosen frequencies in a selected frequency range in said valve comprising a valve seat, a disk or plug for forming a fluid seal with the seat, a stem for driving said disk or plug against the seat, and a valve body having an outside surface using an acoustic transmitting transducer disposed in vibrational contact with the outside surface of said valve and driven by a frequency sweep generator;
receiving resonance vibrations induced in the valve body using an acoustic receiver disposed in vibrational contact with the outside surface of said valve, and converting the received vibrations into electrical voltages;
receiving the electrical voltages and filtering the electrical voltages using a narrow-band, band-pass tracking filter having a center frequency which tracks selected excitation frequencies in the selected frequency range;
storing the filtered electrical voltages, whereby an acoustic resonance spectrum of said valve is generated;
comparing the generated acoustic resonance spectrum of said valve with at least one other acoustic resonance spectrum obtained for said valve in the closed condition thereof; and
determining whether there is a difference between the generated acoustic resonance spectrum and the at least one other acoustic resonance spectrum.

### Claim 8 (depends on 7)

The method of claim 7, wherein the electrical voltages from the acoustic receiver are amplified.

### Claim 9 (depends on 7)

The method of claim 7, wherein the acoustic transmitting transducer and the acoustic receiver are not in physical contact with one another.

### Claim 10 (depends on 7)

The method of claim 7, wherein the acoustic transmitting transducer is swept in frequency in either or both directions by the frequency sweep generator.

### Claim 11 (depends on 7)

The method of claim 7, wherein the acoustic transmitting transducer comprises a piezoelectric transducer and the acoustic receiver is chosen from a piezoelectric transducer and a laser Doppler vibrometer.

### Claim 12 (depends on 7)

The method of claim 7, wherein said step of comparing the generated acoustic resonance spectrum of said valve with another acoustic resonance spectrum obtained for said valve in the closed condition thereof comprises a peak position-based signature correlation.

### Claim 13 (depends on 12)

The method of claim 12, wherein the peak position-based signature correlation is performed using the equation:
Corr
=
100
N
ave
⁢
∑
i
=
1
N
t
⁢
⁢
∑
j
=
1
N
u
⁢
⁢
(
-
{
sgn
⁡
(
f
t
-
f
u
-
δ
⁢
⁢
f
)
-
sgn
⁡
(
f
t
-
f
u
+
δ
⁢
⁢
f
)
}
/
2
)
,
where the subscripts t and u refer to template and unknown, respectively; Nt and Nu are the number of frequency peaks in the template and unknown datasets, respectively; δf is the frequency window used in the correlation, and depends on the tolerances involved; Nave is the average number of resonance peaks in the template and the unknown datasets; and sgn is the mathematical sign function.

### Claim 14 (depends on 7)

The method of claim 7, further comprising the step of determining fluid pressure in the region of the valve seat.

### Claim 15 (depends on 14)

The method of claim 14, further comprising the step of pattern matching the generated acoustic resonance spectrum of said valve with at least one reference acoustic resonance spectrum obtained for said valve in the closed condition thereof for fluid pressure within said valve.

### Claim 16

A method for determining whether a vessel similar or identical in appearance to other vessels is similar or identical thereto, and contains similar fluids thereto, comprising:
generating vibrations having chosen frequencies in a selected frequency range in said vessel from an acoustic transmitting transducer disposed in vibrational communication with the outside surface of said vessel, and driven by a frequency sweep generator;
receiving resonance vibrations induced in said vessel using an acoustic receiver disposed in vibrational communication with the outside surface of said vessel, and converting the received vibrations into electrical voltages;
receiving the electrical voltages and filtering the electrical voltages using a narrow-band, band-pass tracking filter having a center frequency which tracks selected excitation frequencies in the selected frequency range;
storing the filtered electrical voltages, whereby an acoustic resonance spectrum of said vessel is generated;
comparing the generated resonance spectrum of said vessel with at least one acoustic resonance spectrum obtained for another of said vessels; and
determining whether there is a difference between the generated acoustic resonance spectrum and the at least one other acoustic resonance spectrum.

### Claim 17 (depends on 16)

The method of claim 16, wherein the electrical voltages from the acoustic receiving transducer are amplified.

### Claim 18 (depends on 16)

The method of claim 16, wherein the acoustic transmitting transducer and the acoustic receiver are not in physical contact with one another.

### Claim 19 (depends on 16)

The method of claim 16, wherein the acoustic transmitting transducer is swept in frequency in either or both directions by the frequency sweep generator.

### Claim 20 (depends on 16)

The method of claim 16, wherein the acoustic receiver is chosen from an acoustic piezoelectric transducer and a laser Doppler vibrometer.

### Claim 21 (depends on 16)

The method of claim 16, wherein said step of comparing the generated acoustic resonance spectrum of said vessel with at least one other acoustic resonance spectrum obtained for another of said vessels, comprises a peak position based signature correlation.

### Claim 22 (depends on 16)

The method of claim 16, wherein said vessel is chosen from a vaccine vial and a syringe.

### Claim 23

A method for determining the tightness of sealing flanges, comprising a cover flange and a flange attached to a pipe secured by bolts and nuts or a clamp, for accessing fluids in a vessel, comprising:
generating vibrations having chosen frequencies in a selected frequency range in said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel, using an acoustic transmitting transducer disposed in vibrational communication with an outside surface of said pipe or said vessel and driven by an acoustic frequency sweep generator;
receiving resonance vibrations induced in said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel, combined, using an acoustic receiver disposed in vibrational contact with the outside surface of said pipe or said vessel, and converting the received vibrations into electrical voltages;
receiving the electrical voltages and filtering the electrical voltages using a narrow-band, band-pass tracking filter having a center frequency which tracks selected excitation frequencies in the selected frequency range;
storing the filtered electrical voltages, whereby an acoustic resonance spectrum of the combination of said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel, is generated;
comparing the generated acoustic resonance spectrum that includes the frequency range of the combination of said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel, with at least one other acoustic resonance spectrum obtained for the combination of said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel; and
determining whether there is a difference between the generated acoustic resonance spectrum and the at least one other acoustic resonance spectrum.

### Claim 24 (depends on 23)

The method of claim 23, wherein the electrical voltages from the acoustic receiver are amplified.

### Claim 25 (depends on 23)

The method of claim 23, wherein the acoustic transmitting transducer and the acoustic receiver are not in physical contact with one another.

### Claim 26 (depends on 23)

The method of claim 23, wherein the acoustic transmitting transducer is swept in frequency in either or both directions by the frequency sweep generator.

### Claim 27 (depends on 23)

The method of claim 23, wherein the acoustic transmitting transducer comprises a piezoelectric transducer and the acoustic receiver is chosen from a piezoelectric transducer and a laser Doppler vibrometer.

### Claim 28 (depends on 23)

The method of claim 23, wherein said step of comparing the generated acoustic resonance spectrum of the combination of said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel with another acoustic resonance spectrum obtained for the combination of said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel, comprises a peak position-based signature correlation.

### Claim 29 (depends on 28)

The method of claim 28, wherein the peak position-based signature correlation is performed using the equation:
Corr
=
100
N
ave
⁢
∑
i
=
1
N
t
⁢
⁢
∑
j
=
1
N
u
⁢
⁢
(
-
{
sgn
⁡
(
f
t
-
f
u
-
δ
⁢
⁢
f
)
-
sgn
⁡
(
f
t
-
f
u
+
δ
⁢
⁢
f
)
}
/
2
)
,
where the subscripts t and u refer to template and unknown, respectively; Nt and Nu are the number of frequency peaks in the template and unknown datasets, respectively; δf is the frequency window used in the correlation, and depends on the tolerances involved; Nave is the average number of resonance peaks in the template and the unknown datasets; and sgn is the mathematical sign function.

### Claim 30 (depends on 23)

The method of claim 23, further comprising the step of determining fluid pressure in said pipe or said vessel.

### Claim 31 (depends on 30)

The method of claim 30, further comprising the step of correcting the generated acoustic resonance spectrum for the combination of said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel, and at least one other acoustic resonance spectrum obtained for the combination of said sealing flanges, said nuts and bolts or said clamp, said pipe, and said vessel, for fluid pressure within said pipe and said vessel.