Filing Information

Inventor(s)	R. Daniel Costley · Mark Henderson ·
Assignee(s)	Mississippi State University ·  View assignee updates
Primary Examiner	Hezron Williams ·
Assistant Examiner	Jacques Saint-Surin ·
Application Number	US9698227
Filing date	10/30/2000
Issue date	01/22/2002
Predicted expiration date	10/30/2020
U.S. Classifications	735/79  · 737/2  · 73/52  ·
International Classifications	--
Kind Code	B1
International Classifications	73579 · 73574 · 73570 · 73599 · 73602 · 73 1201 · 73 52 · 73290 V · 73702 · 73 5406 ·

Patent Family

Abstract

A method and apparatus for determining the internal pressure of a sealed container are disclosed. The method involves: exciting a lid of the container so as to create at least two modes of vibration having separate frequencies, wherein said frequencies are fundamental, f1, and a second frequency, preferably the second axisymmetric mode, f2; detecting the vibration resulting from said exciting to determine f1, and f2; using f2, which is indicative of internal pressure, to calculate a first value for internal pressure using a first mathematical model that is calibrated to the lid on the sealed container; using f1, which is indicative of volume of contents, to calculate the volume of contents in the sealed container using a second mathematical model that is calibrated to the lid on the sealed container, wherein a natural frequency of said lid is a function of said internal pressure and said volume of contents; and compensating for said volume of contents to determine a second value for internal pressure, wherein said second value for internal pressure is more reliable than said first value for internal pressure. The apparatus for determining the internal pressure of a sealed container of the invention includes: means for exciting a lid of the container so as to create at least two modes of vibration having separate frequencies, wherein said frequencies are fundamental, f1, and a second frequency, preferably the second axisymmetric mode, f2; detecting means for detecting vibration resulting from the exciting of said container to determine f1, and f2; calculating means for calculating a first value for internal pressure of said container using f2; calculating means for calculating the volume of contents of said container using f1; wherein a natural frequency of said lid is a function of said internal pressure and said volume of contents; and calculating means for compensating for said volume of contents to determine a second value for internal pressure, wherein said second value for internal pressure is more reliable than said first value for internal pressure.

Independent Claims | See all claims (6)

1. 1. A method for determining an internal pressure of a sealed container, comprising: exciting a lid of the sealed container so as to create at least two modes of vibration having separate frequencies, wherein said frequencies are fundamental, f1, and a second frequency, f2; detecting the vibration resulting from said exciting to determine f1, and f2; using f2, which is indicative of internal pressure, to calculate a first value for internal pressure using a first mathematical model that is calibrated to the lid on the sealed container; using f1, which is indicative of volume of contents, to calculate the volume of contents in the sealed container using a second mathematical model that is calibrated to the lid on the sealed container; wherein a natural frequency of said lid is a function of internal pressure and volume of contents; and compensating for said volume of contents to determine a second value for internal pressure, wherein said second value for internal pressure is more reliable than said first value for internal pressure.
2. 3. An apparatus for determining an internal pressure of a sealed container, comprising: means for exciting a lid of the sealed container so as to create at least two modes of vibration having separate frequencies, wherein said frequencies are fundamental, fd1; and a second frequency, f2; detecting means for detecting vibration resulting from the exciting of said container to determine f1 and f2; calculating means for calculating a first value for internal pressure of said container using f2; calculating means for calculating the volume of contents of said container using f1; wherein a natural frequency of said lid is a function of said internal pressure and said volume of contents; and calculating means for compensating for said volume of contents to determine a second value for internal pressure, wherein said second value for internal pressure is more reliable than said first value for internal pressure.
3. 5. A method of determining the internal pressure and level of contents within a container comprising the steps of: (a) storing container data into a memory; (b) exciting a lid of the container so as to create at least two modes of vibration having separate frequencies, wherein said frequencies are fundamental, f1, and a second frequency, f2; (c) detecting the vibration resulting from said exciting to determine f1 and f2; (d) producing a frequency spectrum of the detected vibration; (e) isolating values of f1 and f2 from the frequency spectrum; (f) using f2 to calculate an internal pressure using a first mathematical model that is calibrated to the sealed container; and (g) using f1 to calculate the volume of contents in the sealed container using a second mathematical model that is calibrated to the sealed container.