Patent Application
20150316441
Packages maintain the cleanliness and sterility of the product within from the manufacturing plant through transport, shelf life, and storage. Testing of the quality of seal and package integrity is of paramount importance in any packaging industry. As an example, the quality of the seal and integrity of a package dictates the shelf life of food products (e.g., chips, frozen foods, children's beverage/juice packages, meat, dairy products, and fresh vegetables), medical products (e.g., pharmaceuticals), and cosmetic products (e.g., skin care and makeup).
Although many package testing procedures exist, many of these tests involve destructive methods that are not adaptable to in-line testing. Therefore, test packaging or off-line samples are utilized for the testing, making it difficult to ensure the in-line packages are reliable and/or requiring a reduced yield in order to provide sufficient samples for off-line testing. In addition. the current non-destructive tests are time consuming, also resulting in reduced yield or fewer packages being tested on-line. Accordingly, there is a need in the art for fast, reliable integrity and quality of seal testing that can be performed in-line with packaging a product.
Testing methods and equipment are provided for fast, non-destructive testing of the integrity and/or quality of seal for a variety of packages.
In an embodiment, a solenoid/gravity system is used to rapidly pressurize a flexible package to any desired pressure and to rapidly withdraw the pressurizing agent. Another) solenoid is used to rapidly and retractably impact a point on a package under test. Sensors are used to sense data corresponding to the behavior of the package after the package is impacted, such as data corresponding to a wave in the package generated from a point of impact. The data is acquired and processed to determine information regarding a leak in the package, such as whether there is a leak in the package under test, the size of the leak, and/or the location of the leak.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Embodiments of the subject invention relate to methods and apparatus for non-destructive testing of the integrity and/or quality of seal for a package. Embodiments can be applied to a variety of packages Implementations of embodiments of the invention can be used to test packages with flexible and/or compliant packaging, such as plastic packages, metal foil packages, PET, polypropylene, coated materials, polyolefins, paper, polyester, BOPET, BOPP, metalized BPP (biaxially-oriented polypropylene), PVDCpet, nylon, and aluminum foil (e.g., packages used to protect chips, frozen foods, medical supplies, cosmetics, etc.). According to certain embodiments, a method is provided utilizing dynamic impact characterization to determine whether a loss of pressure due to a leak in the package occurs.
Package testing includes ensuring the integrity of the sealed package, and assuring that no weaknesses in the sealed areas of the package permit leaks to develop with handling stresses and time. Package integrity testing can be referred to as a “leak test” of the package. That is, package integrity testing determines whether there is a failure in the materials or process that allows contamination to enter. Seal strength testing, on the other hand, measures an attribute of the seal, which is designed to ensure that the seal presents a barrier to at least the same extent as the rest of the package. Both integrity and seal testing are important aspects of ensuring proper packaging.
Package integrity testing is a measure of the package's barrier material and seal, providing a “leak test” of the whole package. In addition to seal bonding failures or disrupted seals, leakage can be the result of large holes, pinholes, or cracks in package materials. Either source of leakage represents the potential for product contamination from elements of the ambient atmosphere outside of the package entering the package, and the potential for the materials inside the package to escape.
Testing methods and equipment are provided for nondestructive testing of the quality of seal and/or integrity of a package. Embodiments can be designed for fast testing, such that the testing can be in-line with the packaging process.
Embodiments of the invention provide package testing capable of non-intrusive and less disruptive testing as compared to many existing test methods. According to certain embodiments, the nature of defects in a package seal can be identified. In specific embodiments, the general location of the defect can be identified.
In addition, methods and equipment described herein can be applied to any on-line production process for rapid evaluation of the quality of seal and/or package integrity. Implementations of embodiments of the subject apparatus can be provided in-line at a back-end of the product packaging process. In an embodiment, the package can be guided into, for example, a channel, where one or more forces can be applied to increase the internal pressure of the package. The pressurized package can then be impacted by a mechanism to apply a force to a region of the pressurized package over a short duration and then remove the force.
In specific embodiments, the impact can last less than 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, and/or less than 0.25 seconds, and/or can last in a range between two for these time durations.
The existence and location of a leak can be quickly and easily determined by performing a non-destructive impact/blow on the package and comparing the force signatures generated by sensors in contact with the package and/or displacement detected by sensors in contact with or associated with the package.
According to one embodiment, an initial pressure is applied to a package under test. In one embodiment, the initial pressure can be applied by a restraining plate that holds the package in place. In various embodiments, the application of initial pressure can include, but is not limited to, negative pressurization, any “mechanical” form of pressurization, pressurization in a vertical direction, pressurization in a horizontal direction, pressurization by guiding the package between two rails/belts, pressurization by gravity, use of materials other than a rigid plate for pressurization, pressurization by clamps in corner(s) and/or edges of package, using transducers to both sense and apply pressure, use of a linear actuator or other motor to drive pressurization plates, use of pneumatic system, or a combination thereof
In a specific embodiment, the force that applies the initial pressure is applied by pushing on the external surface of the package with one or more force sensors, or displacement sensors, where the force sensors monitor the force applied to the package, and detect the behavior of the package material after impact. The sensor can also monitor the package upon applying the force(s) to pressurize the package and determine when the package has reached an equilibrium after the application of the pressurization force(s) to then trigger impact, and then produce data regarding the force, or displacement, experienced by the sensor(s) after impact. In a specific embodiment, a time delay, e.g. of at least 100 msec, 200 msec, 300 msec, 400 msec, 500 msec, or in a range between two of these time durations can be allowed after initial pressurization before triggering the impact, to allow the package to reach equilibrium. The structures holding the sensors in contact with the package can be low vibration structures and hold their position accurately during and after the impact.
After initial pressure is applied, a region of the package is impacted with a force sufficient to create a disturbance to the package while not destroying the package. The impact can be performed, for example, by using an impacting rod. In some embodiments, the impact can be accomplished by ultrasound excitation of content, an impact by air gun, gravity weight, projectile, pendulum, electromagnetic (EM) wave, steady jet, worm gear, linear actuator, combination of gravity and a pendulum, hydraulic, or a combination thereof. Of course, embodiments are not limited thereto.
Solenoids can be used to control pressure and the impact, such as force of impact, depth of impact, and/or duration of impact.
In one embodiment, force sensors/transducers in contact with the package and spaced a distance away from the impact region of the package detect a force signature from the impact. The existence of a leak is determined by evaluating the force signature. In other embodiments, displacement can be measured using a vision system, a strain gauge, a capacitive detector, a laser system, radar, sonar, and the like. The displacement of the package at one or more points or regions of the package can be measured. In some embodiments, an analog response can be used instead of a transducer.
When a seal or package is intact and of good quality, the four transducers provide similar force signatures, i.e., the four signals have the same amplitude, duration and shape. However, when there is leak, either the sensor(s) closest to the location of the leak may show a different reading or all the four signals generated by the transducers will be of slightly lower amplitude and longer duration. Specific embodiments can apply a pressure and then hold the position of the pressure applying equipment in a constant relative position to the package, such that the pressure may drop if there is a leak. Other embodiments can apply a pressure and then maintain the pressure during the testing.
A specific embodiment can place a carriage on top of the package, such that a constant weight is applied to the package, and if the contact area between the carriage and package are maintained a constant pressure is applied to the package. Which one of these two scenarios will occur depends on the size of the package, size of the leak, distance of the leak location from the transducer, pressure inside the package, duration and amplitude of the impact, external pressure applied by the plate on the package, method of holding, etc. In a specific embodiment, the sensors are positioned to be equidistant from the region of impact such that the force or displacement signatures are similar when no leak is present. Other embodiments can position the sensor at different distances or positions with respect to a package structure in order to achieve a desired data gathering characteristic. An embodiment can use 1, 2, 3, 4, or more such sensors.
The sensors can detect a wave generated from point of impact. A weaker signal can imply a leak near that sensor due to the reduced pressure in that area.
A specific embodiment can protrude the sensor from a plate or other structure such that the sensors are the only structure in contact with the package (i.e., the plate is not in contact with the package) and the sensors apply the force in the vicinity of the impact. Of course another structure on the other side of the package may provide one or more forces to the other side of the package as the sensors push on the package. In a specific embodiment, there is no other structure in contact with the package between the region of impact and the sensors applying the force(s) for pressurization. A plate can be used to push the sensors while the sensors push the package.
Certain embodiments are directed to one or more of: performing leak detection in under 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and/or 0.9 seconds, or in a range between any two of these listed time durations, being sensitive to leaks greater than 25, 50, 75, 100, 125, 150, 175, and/or 200 micrometers, having a false positive rate under 0.0004%, 0.0005%, 0.0006%, 0.0007%, 0.0008%, 0.0009%, and/or 0.001%, being automated, having a sanitary design, and a relatively long lifespan (e.g., 15+ years).
A greater understanding of the present invention and of its many advantages may be had from the following examples, given by way of illustration. The following examples are illustrative of some of the methods, applications, embodiments and variants of the present invention. They are, of course, not to be considered in any way limitative of the invention. Numerous changes and modifications can be made with respect to the invention.
According to an embodiment, a solenoid/gravity system is used to rapidly pressurize a flexible package to any desired pressure and to rapidly withdraw the pressurizing agent. Alternatively, the forces creating the pressurization can be independent of gravity and be applied by a solenoid or other mechanism to apply force, such as a spring or other passive device, or other known device. Another solenoid can be used to rapidly and retractably impact a point on a package under test. Alternative embodiments can use other physical mechanisms to apply the impact such as a spring loaded arm, a projectile, or other device.
Returning to the embodiment shown in
A top plate H can support the impacting system. By suspending the impacting system from the top plate H, gravity can be used to impart pressure and assist in the impact. Specific embodiments can lock the plate in place to avoid or reduce movement of the plate due to the impact. Accordingly, embodiments, including the embodiment shown in
The impacting mechanism for the embodiment shown in
Other analysis techniques can be used to determine whether a leak exists, how big the leak is, and/or where the leak is. A leak in a package can result in an increased force or displacement signal amplitude when performing leak testing. In specific embodiments, a distinct trough in the signal can occur immediately following the initial peak, indicating a leak. Benchmarks of peaks and troughs for signals of non-leak bags can be benchmarked, and then, when a package or bag is tested, statistical analysis is performed to determine whether the signal has significantly different peaks and troughs than the benchmark, in order to determine whether there is a leak. In an embodiment, this analysis is performed for all four sensors, so the leak determination can be made if 1-2 (or any number) of sensors agree that the signal is significantly different from the benchmark.
In addition, or instead of, the first peak or trough of the signal, additional peaks and troughs can be used in characterization. The period of oscillation of the signal can also be utilized in leak determination. Changes in this characteristic can be effective in detecting leaks.
Specific embodiments of the detection protocol can utilize one or more of the following:
the magnitude of the initial peak, where certain bag types may cause the initial peak to be inverted, certain packages may have a higher magnitude with a leak and others a lower magnitude;
the magnitude of 2nd, 3rd, or other later peaks, where these later peaks may or may not be evident on the graphs shown in
the magnitude of the initial trough;
the magnitude of later troughs;
the comparison (e.g., ratio, spacing) of initial or later peaks to each other (for an example—this characteristic can be determined using the logarithmic decrement (http://en.wikipedia.org/wiki/Logarithmic_decrement));
the comparison of initial or later troughs to each other using logarithmic decrement;
the period of oscillation determined by identifying a time difference between any peak or trough, such as finding the time difference between the first and second peak, or using other peaks or troughs (for example, if the time difference is found between the 3rd peak and 3rd trough, then that time difference can be multiplied by 2 to find the actual period. However, if the time difference is found between the 1st peak and 3rd peak, that time difference can be divided by 2 to find the actual period);
the frequency of oscillation of the signal, which can be related to the period of the signal;
the calculated natural frequency of the package or material in the package, or the material/package combination, based on the signal;
the calculated resonant frequency of the material based on the signal;
this material could encompass the material of the package and/or the contents of the package;
the amount of time between the impact and the initial peak or trough (this can determine how long it actually takes for the wave to travel from the impact to the sensor. Similarly, this time period can be characterized by the amount of time between the impact and a later peak or trough);
characterizing the signal by referencing a peak to the time the impacting rod is released rather than the timing of the impact itself. Any other significant reference point in the testing process can be used to determine the location of a specific peak or trough;
the damping ratio of the signal (http://en.wikipedia.org/wiki/Damping_ratio);
the total energy transmitted by the impact to the sensor via the propagating wave; and
the area under the curve from the beginning of the wave to the time where the wave is dissipated can be used to determine the energy of the impact. Similarly, the area can be taken during a specified time frame (for example, from the start of the wave until 5 milliseconds later). The signal could also be normalized before finding the area by subtracting the DC offset.
Specific embodiments can utilize multiple impacts of the package while the package is under a constant pressurization or a changing pressurization. A specific embodiment makes two separate impacts and take measurements from the wave that propagates for each impact. From that, the leak determination is made by comparing the second impact to the first impact for either each individual sensor or an average of all four (or other number) sensors. In an embodiment, if the second impact produces a lower magnitude initial peak and trough, then it is determined that a leak exists. However, if the second impact produces the same magnitude leak/trough as the first impact, then the bag does not have a leak. Statistical analysis has been performed on this data to determine whether there is a leak.
The graph in
Referring to
Other specific methods utilizing multiple impacts can include one or more of the following:
use individual sensors rather than an average of multiple sensors, allowing a leak determination to be made if, for example, 3 out of 4 sensors had a larger peak amplitude on the second impact;
using more than 2 impacts, where, optionally, comparisons among subsequent impacts can provide additional data for determining leak existence;
the leak determination can be made through some other statistical analyses known in the art, (such as a hypothesis test or t-test); and
other signal characteristics are compared between first and second (or subsequent) impacts, such as the characteristics discussed above for embodiments using a single impact.
A weighted average can be used with other characteristics. As an example, a larger first peak amplitude can be worth 2 points toward a leak determination, whereas a larger trough can be just 1 point. Then the leak determination is made when a certain point value is reached.
A specific embodiment relates to a method of leak detection of a package comprising:
pressurizing a package by applying an initial pressure through a plate controlled by a solenoid;
impacting a region of the package under control of an impact solenoid;
acquiring data relating to the impacting of the region from at least one sensor;
determining an existence of a leak by normalizing data related to a first peak magnitude from the at least one sensor and comparing the normalized data to a threshold.
A specific embodiment relates to a system for leak detection of a package, comprising:
a lifter for holding a pressurizing and impacting system above a package;
a solenoid controlling a release of the lifter to apply an initial pressure onto the package;
a solenoid controlling an impacter for impacting a region of the package; and
at least one sensor for acquiring data relating to the impacting of the region.
A specific embodiment relates to a system for leak detection of a package, comprising:
a pressurization and impact module controlling solenoids to lift/lower a pressurizing and impacting apparatus;
a data acquisition module to read sensor outputs and perform conversions including analog to digital conversion and/or conversion to an indication of force; and
a signal processing module to calculate presence and location of leaks.
This embodiment can optionally configure the signal processing module to normalize data corresponding to a first peak of a signal received by the data acquisition module and compare the normalized data to a threshold.
Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. In addition, any elements or limitations of any invention or embodiment thereof disclosed herein can be combined with any and/or all other elements or limitations (individually or in any combination) or any other invention or embodiment thereof disclosed herein, and all such combinations are contemplated with the scope of the invention without limitation thereto.
Aspects of the invention, such as controlling pressurization and impacting the package, signal acquisition from the sensors, and processing the data collected to analyze the package quality and/or integrity, may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that the invention may be practiced with a variety of computer-system configurations, including multiprocessor systems, microprocessor-based or programmable-consumer electronics, minicomputers, mainframe computers, and the like. Any number of computer-systems and computer networks are acceptable for use with the present invention.
Specific hardware devices, programming languages, components, processes, protocols, and numerous details including operating environments and the like are set forth to provide a thorough understanding of the present invention. In other instances, structures, devices, and processes are shown in block-diagram form, rather than in detail, to avoid obscuring the present invention. But an ordinary-skilled artisan would understand that the present invention may be practiced without these specific details. Computer systems, servers, work stations, and other machines may be connected to one another across a communication medium including, for example, a network or networks.
As one skilled in the art will appreciate, embodiments of the present invention may be embodied as, among other things: a method, system, or computer-program product. Accordingly, the embodiments may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware. In an embodiment, the present invention takes the form of a computer-program product that includes computer-useable instructions embodied on one or more computer-readable media.
Computer-readable media include both volatile and nonvolatile media, transient and non-transient media, removable and nonremovable media, and contemplate media readable by a database, a switch, and various other network devices. By way of example, and not limitation, computer-readable media comprise media implemented in any method or technology for storing information. Examples of stored information include computer-useable instructions, data structures, program modules, and other data representations. Media examples include, but are not limited to, information-delivery media, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile discs (DVD), holographic media or other optical disc storage, magnetic cassettes, magnetic tape, magnetic disk storage, and other magnetic storage devices. These technologies can store data momentarily, temporarily, or permanently.
The invention may be practiced in distributed-computing environments where tasks are performed by remote-processing devices that are linked through a communications network. In a distributed-computing environment, program modules may be located in both local and remote computer-storage media including memory storage devices. The computer-useable instructions form an interface to allow a computer to react according to a source of input. The instructions cooperate with other code segments to initiate a variety of tasks in response to data received in conjunction with the source of the received data.
The present invention may be practiced in a network environment such as a communications network. Such networks are widely used to connect various types of network elements, such as routers, servers, gateways, and so forth. Further, the invention may be practiced in a multi-network environment having various, connected public and/or private networks.
Communication between network elements may be wireless or wireline (wired). As will be appreciated by those skilled in the art, communication networks may take several different forms and may use several different communication protocols. And the present invention is not limited by the forms and communication protocols described herein.
All patents, patent applications, provisional applications, and publications referred to or cited herein are incorporated by reference in their entirety, including all figures and tables, to the extent they are not inconsistent with the explicit teachings of this specification.
It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application.
The present application claims the benefit of U.S. Provisional Application Ser. No. 61/733,754, filed Dec. 5, 2012, and U.S. Provisional Application Ser. No. 61/813,993, filed Apr. 19, 2013, both of which are hereby incorporated by reference herein in their entirety, including any figures, tables, or drawings.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2013/073391 | 12/5/2013 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61733754 | Dec 2012 | US | |
| 61813993 | Apr 2013 | US |
