TITLE GAS PERMEATION TESTING SYSTEM

CROSS-REFERENCE TQ RELATED APPLICATION

[0001] This application claims the benefit of United States Provisional Patent Application Serial No. 60/950,697 filed on July 19, 2007 hereby incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to a container testing apparatus, and, more particularly, to a system and method for measuring the permeation of a gas through the walls of a container.

BACKGROUND OF THE INVENTION

[0003] In the preservation of beverages which are liable to be affected by oxidation, there is a problem that the beverages are oxidized by a small amount of oxygen present in a container used for storage. Therefore, it is of paramount importance to ascertain the oxygen permeation characteristics of the plastic containers to be used for the beverage storage. In the prior art, the systems for testing oxygen permeation require that each time a container is placed on or removed from a system for gas permeation testing, the containers to be tested must be affixed onto flat plates which have soldered connections that must be screwed onto a mating fitting of an associated manifold. Frequently, testing errors result, primarily from minute leakage around the fittings and components. Problems further increase with repeated use of the fittings. [0004] One solution is to replace the fittings more often and to more meticulously affix the container to the flat plates to ensure a better connection. However, these options significantly increase the amount of time between testing of containers while still allowing for testing errors.

[0005] Furthermore, current operation of gas permeation test systems may require a user to manually manipulate the flow rate and pressure of a carrier gas

into the container. Manual manipulation of the carrier gas flow rate and pressure results in imprecise control of the carrier gas within the system, thereby resulting in testing errors. Imprecise control of carrier gas flow rate and pressure also results in wear to the components of the system, thereby reducing the useful life thereof.

[0006] Those skilled in the art have continued to search for the solution of how to provide a practical testing system.

SUMMARY OF THE INVENTION

[0007] Concordant and congruous with the present invention a system for automated regulation of the gas permeation test system with a control system to facilitate more precise control of test conditions, has surprisingly been discovered.

[0008] In one embodiment of the invention, a gas permeation test system 110 for measuring the permeation of a gas through a container comprises a gas permeation test system in fluid communication with a source of pressurized fluid adapted to generate a feedback signal representing at least one measured characteristic; and a control system in communication with the gas permeation test system adapted generate a control signal to adjust operation of the gas permeation test system in response to the feedback signal. [0009] In another embodiment, a gas permeation test system 110 for measuring the permeation of a gas through a container comprises a test system in fluid communication with a source of pressurized fluid adapted to generate a feedback signal representing one of a measured characteristic of a fluid; a means for regulating a flow of the fluid; and a control system in communication with the gas permeation test system adapted to generate a control signal to adjust operation of the gas permeation test system in response to the feedback signal.

[0010] In another embodiment, a method of controlling the gas permeation testing of blow molded containers includes the steps of: providing a gas permeation test system; securing a container to the gas permeation test system;

measuring a characteristic of a pressurized fluid caused to flow through the gas permeation test system and container and generating a feedback signal representing the measured characteristic; and adjusting operation of the gas permeation test system in response to the feedback signal to effect the desired change to the pressurized fluid caused to flow through the gas permeation test system.

[0011] Further objects and advantages of the invention will be apparent from the following description and appended claims, reference being made to the accompanying drawings forming a part of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Other objects and advantages of the invention will become readily apparent to those skilled in the art from reading the following description of the invention when considered in the light of the accompanying drawings, in which: [0013] Figs. 1a, 1 b, 1c, and 1d are, respectively, top plan, end elevational, front elevational, and perspective views of a sample plate of a gas permeation testing system embodying features of the present invention; [0014] Figs. 2a, 2b, 2c, and 2d are, respectively, top plan, end elevational, front elevational, and perspective views of a manifold of the gas permeation testing system embodying features of the present invention; [0015] Figs. 3a, 3b, and 3c are, respectively, end elevational, top plan, and front elevational views of a base plate of the gas permeation testing system embodying the features of the present invention;

[0016] Fig. 4 is a perspective view of the gas permeation testing system embodying the features of the present invention;

[0017] Fig. 5 is a schematic block diagram of a gas permeation testing system 1 10 according to the present invention incorporating the components illustrated in Figs. 1-3; and

[0018] Fig. 6 is a view of a gas permeation testing system 1 10 according to the present invention incorporating the components illustrated in Figs. 1-3.

[0019] It is to be understood that the present invention is not limited in its application to the details of construction and arrangement of components illustrated in the accompanying drawings, since the invention is capable of other embodiments, and of being practiced or carried out in various ways within the scope of the appended claims. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description, and not of limitation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner.

In respect of the methods disclosed, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical.

[0021] Referring to the accompanying drawings, there is shown components of a gas permeation testing system for mounting and connecting plastic material and a control system, such as used in containers for permeation testing which embody the features of the invention.

[0022] The gas permeation testing system includes two main components; namely, moveable sample plates to which a container to be tested is affixed; and an associated manifold system.

[0023] A sample plate, generally indicated by reference numeral 10, is shown in Figs. 1a, 1b, 1c, and 1d is adapted to be capable to receive pins of an associated manifold 30 shown in Figs. 2a, 2b, 2c, and 2d. The sample plate 10 and the manifold 30 are suitably affixed to a base plate 50 shown in Figs. 3a, 3b, and 3c by suitable fasteners. The sample plate 10, the manifold 30, and the base plate 50 are assembled to form the gas permeation testing assembly 100 as shown in Fig. 4.

[0024] The sample plate 10 includes a main body 12 having an annular recess 14 for receiving the open end of the neck or finish of a plastic container to

be tested. The recess 14 is defined by an annular shoulder 16. A coaxial recess 18 is formed centrally of the annular shoulder 16. The open end of the recess 18 is defined by an upstanding annular ring 20. A conduit 22 is formed in the main body 12 to provide communication between a remote source of pressure fluid and the interior of the container being tested.

[0025] A similar conduit 24 is formed in spaced relation therefrom in the main body 12 to provide communication with a return of the pressure fluid introduced through the conduit 22. Spaced apart bushings 26 and 28 are formed to extend inwardly of the main body 12 and receive cooperating locating pins, as will be explained hereinafter.

[0026] Figs. 2a, 2b, 2c, and 2d illustrate a manifold, generally indicated by reference numeral 30, includes a main body 32 having a conduit 34 to communicate with the inlet of the sample plate conduit 22; and a conduit 36 to communicate with the sample plate conduit 24. Coupling means including spaced apart pins 38 and 39 are provided to selectively couple the sample plate 10 and the manifold 30.

[0027] Grooves may be circumscribed around the inlets and outlets of conduits of the sample plate 10 and the manifold 30 to receive o-ring seals, for example. The seals are utilized to provide fluid-tight system when the sample plate 10 is in operative position.

[0028] Any suitable means of selectively coupling the sample plate 10 and manifold 30 may be used. It has been found that satisfactory results may be achieved by utilizing the spaced apart inwardly extending bushing 26 and 28 in the sample plate 10 which receive the respective pins 38 and 39 of the manifold 30. Manifold mold-style pins 38 and 39 ensure proper alignment with sample plate mold-style bushings 26 and 28.

[0029] The manifold 30 can be mounted to a base plate, generally referred to by reference numeral 50 illustrated in Figs. 3a, 3b, and 3c. The base plate 50 serves as a support for the sample plate 10 and the manifold 30. The manifold 30 is provided with spaced apart passageways or holes 40 and 42 to receive suitable threaded fasteners. The threaded fasteners are received within

internally threaded holes 52 and 53, respectively, of the base plate 50 to assure proper alignment. A pair of spaced apart passageways or holes is formed in the base plate 50 to allow the passage of conduits communicating with the manifold conduits 34, 36. In the embodiment illustrated, the base plate 50 is adapted to accommodate a pair of manifolds 30.

[0030] Once aligned, the sample plate 10 is connected with the manifold 30. The connection may be tightened to urge the sample plate 10 against o-rings in the manifold 30. Compression of the sample plate 10 against the o-rings results in a fluid-tight conduit-container-manifold system.

[0031] The sample plate 10, manifold 30, and base plate 50 are preferably constructed of aluminum or other lightweight durable alloy. Lightweight components are desired for easier portability of system components and allow rapid exchange of sample plates during testing. However, the components of the system may be constructed of any appropriate material that withstand system temperature, pressure, and use requirements.

[0032] The testing of a container typically involves the following steps. First, the open side of a container to be tested is placed in the recess 14 and secured to the sample plate 10 with an epoxy resin or other suitable adhesive material. The sample plate 10 is then selectively coupled to the manifold 30 which has been attached to the base plate 50. The sample plate 10 is securely compressed against the o-rings received within the conduits of the manifold 30 to close the system. Compression occurs by tightening the connection between the sample plate 10 and the manifold 30 by any means, such as by clamping, for example.

[0033] After the system has been closed, the pressure fluid is allowed to flow into the container being tested through the manifold conduit 34 and the sample plate conduit 22. Favorable results have been found wherein the pressure fluid is pure nitrogen. As the pressure fluid is introduced into the container, it flows out of the container through the sample plate conduit 24 and the manifold conduit 36. Any gas which permeated through the container during the test, will also flow

out of the container through the sample plate conduit 24 and the manifold conduit 36 to the testing sensor.

[0034] A system described above for testing the permeation characteristics of a container may also be used to test permeation characteristics of a film, for ^" example. A film may be disposed on an open-ended container and sealed or otherwise connected to the container so the flow of fluid around the film into the container is militated against. The sample plate conduits 22, 24 described herein are in communication with the container. The pressure fluid is introduced into the container and exposed to the inner side of the film. The outer side of the film is exposed to atmosphere or a controlled environment. Gas which permeates through the film is picked up by the pressure fluid and tested to determine the permeation characteristics of the film.

[0035] Figs. 5 and 6 illustrate a gas permeation testing system 110 including a plurality of gas permeation testing apparatus 100 as shown in Figs. 1-4 and described herein and having at least one oxygen sensor and at least one sample presence detector. A control system 116 in electrical communication with the gas permeation testing system 110 is adapted to detect or measure at least one of the following: the flow of the pressurized fluid into a container disposed on the gas permeation testing system 110; the presence of the pressurized fluid in the system 110; the pressure of the pressurized fluid in the system 110; the temperature of the pressurized fluid; and the presence of a leak of the fluid from the system 110. The control system 116 is further adapted to generate a feedback signal based on at least one of the measured characteristics. An . unexpected loss in the pressure of the fluid in the system 1 10 may indicate a leak in the system 110 or a lack of fluid from a fluid source. Electrical connections are indicated by dashed lines in Fig. 5. The control system 116 is further in communication with a data processor adapted to receive and interpret data. As shown in Figs. 5 and 6, the data processor is a computer 120 including software adapted to receive and interpret the feedback signal from the gas permeation testing system 110.

[0036] The gas permeation testing system 110 is installed downstream from a source of pressure fluid 112. A means for regulating 114 a flow of a pressure fluid stored in the source of pressure fluid 112 is disposed between the oxygen sensor of the system 1 10 and the source of pressurized fluid 1 12. The means for regulating 1 14 is a three-way valve in fluid communication with the source of pressure fluid 112, the gas permeation testing system 110, and an exhaust system 118. The means for regulating 114 may be any valve, such as a solenoid valve or a gas pressure regulator, for example. The gas permeation testing system 1 10 may also include a pressure sensor, as desired. It is also understood that the system 1 10 may include any number of means for regulating 114, as desired.

[0037] The gas permeation testing system 110 is adapted to generate a feedback signal representing a measured or monitored characteristic of the fluid caused to flow through the system 1 10 and/or the presence of a sample. The feedback signal is received by the control system 116 and the control system 116 generates a control signal which is sent to the flow regulator 114, the source of pressure fluid 112, the gas permeation testing system 110, and/or any other component of the system 110, as desired, to facilitate adjustment and feedback control of the system 1 10. System changes may include a change in the characteristics of the pressurized fluid flowing through the system 1 10, such as changes to the flow rate, the pressure, and the temperature of the fluid, for example. System changes may also include adjustment of the means for regulating 114 to militate against fluid flow to a particular system component. For example, fluid from the fluid source 112 may be caused to flow through the gas permeation testing system 110, past the oxygen sensor for detection and measurement, and then to the exhaust system 118. However, if the sample presence detector sends a feedback signal to the control system 116 and/or the computer 120 indicating the lack of a sample, the control system 1 16 will review the feedback signal and direct a control signal to a desired component. If the feedback signal is also sent to the computer 120 for interpretation, the software of the computer will review the feedback signal and direct the control signal 116

to direct a control signal to a desired component. If a sample is not present, the control signal will be sent to the means for regulating 114 to cause an adjustment thereto to facilitate the bypass of the fluid from the gas permeation system 110 to the exhaust system 1 18 without flowing past the oxygen sensor. The control system 116 or the computer 120 may also cause an adjustment to the means for regulating 114 in the event of a pressure drop in the gas permeation testing system 1 10 to cause the fluid to bypass the oxygen sensor. By bypassing the fluid around the oxygen sensor, the oxygen sensor may be isolated to militate against exposure of the oxygen sensor to oxygen to extend a useful life thereof. [0038] Additionally, before the measurement of a new sample, the gas permeation testing system 1 10 and the means for regulating 114 may be configured to facilitate a bypass of the fluid around the oxygen sensor to purge the gas permeation testing system 110 and/or a testing apparatus 100. Once the purge operation is complete, the gas permeation testing system 110 and the means for regulating 114 may be configured to facilitate a flow of the fluid past the oxygen sensor for measurement and the testing of a sample. [0039] The gas permeation testing system 110 may include a plurality means for regulating such as a three-way valve and a two-way valve. The plurality of means for regulating may by driven together to facilitate adjustment thereof in concert. The plurality of means for regulating is in electrical communication with the controller 116 which is in electrical communication with the computer 120. In a first position, the plurality of means for regulating facilitates the flow of fluid through the sample, past the oxygen sensor for measurement, and then to the exhaust system 1 18. In a second position, the plurality of means for regulating facilitates the bypass of the fluid through the sample, around the oxygen sensor, and to the exhaust system 1 18.

[0040] Information related to the feedback signal obtained by the control system 1 16, as well as any adjustments made to the system 110 by the control system 116, may be displayed to an operator on a display device of the computer 120 for real time data and data trend analysis. An alarm signal may also be sent to the computer 120 from the control system 116 or from the computer 120 to

alert an attendant of an event requiring corrective action. For example, in the event of a leak of the fluid from the system 110, the gas permeation testing system 110 may send a feedback signal to the control system 116 to trigger an alarm signal to be sent to the computer 120. Once the attendant is notified of the event or alarm, the system 110 may be adjusted or shut-down for repair. [0041] The feedback control according to the present invention will generate the required recommended process control functions. These controls will allow for better process monitoring, less need for labor to intervene in the process, more precise control of the pressurized fluid in the system 110, militate against process error, and militate against wear on the components of the system 110 contacted by the pressurized fluid.

[0042] From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.