Instrument and method for measuring the volume of a hermetically sealed variable volume and pressure conforming container

• US 7,252,014 B1
• Filed: 04/17/2006
• Issued: 08/07/2007
• Est. Priority Date: 04/17/2006
• Status: Active Grant

• Current Assignee: MOCON, Inc. (Ametek Incorporated)
• Original Assignee: MOCON, Inc. (Ametek Incorporated)
• Inventors: Mayer, Daniel W., Ascheman, Timothy A.
• Primary Examiner(s): PATEL, HARSHAD R
• Application Number:
  US11/405,215
• Time in Patent Office: 477 Days
• Field of Search: None
• US Class Current: 73/861
• CPC Class Codes: G01F 17/00 Methods or apparatus for determining the capacity of containers or cavities, or the volume of solid bodies measuring linear dimensions to determine volume G01B
• CPC Class Codes: G01F 22/02 involving measurement of pressure
• CPC Class Codes: G01M 3/3272 for verifying the internal pressure of closed containers

Abstract

An instrument and method for measuring the volume of a hermetically sealed, variable volume, pressure conforming container. The instrument includes a needle, a vacuum pump, a mass flow rate sensor and an integrator. The needle has a lumen operable for sealingly perforating a container and thereby placing the lumen of the needle in fluid communication with a retention chamber defined by the container. The vacuum pump evacuates the gaseous content from the retention chamber through the lumen defined by the needle and past a mass flow rate sensor for sensing mass flow rates pulled through the lumen and transmitting corresponding mass flow rate signals over time to the integrator. The integrator is programmed to integrate the received mass flow rate signals over time through achievement of an evacuated retention chamber to generate a total mass value, and calculate a volume from the total mass value employing the Ideal Gas Law.

Claims

1. An instrument for measuring volume of a hermetically sealed, variable volume, pressure conforming container, comprising:

(a) a needle having a lumen operable for sealingly perforating a hermetically sealed, variable volume, pressure conforming container so as to place the lumen of the needle in fluid communication with a retention chamber defined by such a container,

(b) a vacuum pump in fluid communication with the lumen effective for evacuating gaseous content from a hermetically sealed, variable volume, pressure conforming container via the lumen defined by the needle,

(c) a mass flow rate sensor in sealed fluid communication with the lumen defined by the needle for sensing mass flow rates pulled through the lumen and transmitting corresponding mass flow rate signals over time,

(d) an integrator (i) in electrical communication with the mass flow rate sensor for receiving the mass flow rate signals, and (ii) programmed to (A) integrate the received mass flow rate signals over time through achievement of an evacuated retention chamber to generate a total mass value, and (B) calculate a volume from the total mass value employing the ideal gas law.

2. The instrument of claim 1 further including a display unit for displaying the calculated volume.

3. The instrument of claim 1 further including a means for interfacing with and downloading the calculated volume to a processing unit for reporting, storage in a database, or use in additional algorithms.

4. A method of measuring volume of a hermetically sealed, variable volume, pressure conforming container, comprising:

(a) obtaining a hermetically sealed, variable volume, pressure conforming container defining a retention chamber,

(b) suctioning fluid from the retention chamber through a mass flow rate sensor for sensing mass flow rates of fluid suctioned from the retention chamber over time,

(c) integrating the sensed mass flow rates over time through achievement of an evacuated retention chamber to generate a total mass value, and

(d) calculating a volume for the container from the total mass value employing the ideal gas law.

5. The method of claim 4 further comprising displaying the calculated volume.

6. The method of claim 4 further comprising downloading of the calculated volume to a separate processing unit.

7. The method of claim 4 wherein the hermetically sealed, variable volume, pressure conforming container is a flexible bag filled with a particulate snack food.

8. The method of claim 7 wherein the flexible bag defines a headspace containing a gas with a reduced concentration of O₂.

9. The method of claim 8 wherein the snack food is potato chips.

10. The method of claim 9 wherein the gas is suctioned from the retention chamber by (i) sealingly perforating the container with a needle having a lumen so as to place the lumen of the needle in fluid communication with the retention chamber defined by the container, and (ii) operating a vacuum pump in sealed fluid communication with the lumen.

11. The method of claim 8 wherein the gas is suctioned from the retention chamber by (i) sealingly perforating the container with a needle having a lumen so as to place the lumen of the needle in fluid communication with the retention chamber defined by the container, and (ii) operating a vacuum pump in sealed fluid communication with the lumen.

12. The method of claim 4 wherein fluid is suctioned from the retention chamber by (i) sealingly perforating the container with a needle having a lumen so as to place the lumen of the needle in fluid communication with the retention chamber defined by the container, and (ii) operating a vacuum pump in sealed fluid communication with the lumen.