Method and apparatus for quality of seal and package integrity testing

Abstract

Testing methods and equipment are provided for fast, non-destructive testing of the quality of seal and/or integrity of a package. According to certain embodiments, dynamic impact characterization is used to determine whether a loss of pressure due to a leak in the package occurs. The methods and equipment can be used in-line with product packaging processes. According to one embodiment, an initial pressure is applied to a package under test. A region of the package is impacted with a force sufficient to create a disturbance to the package while not destroying the package by using an impacting rod. 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.

What is claimed is: 
     
         1 . A method of leak detection of a package, the method comprising:
 providing an initial pressure to the package, wherein the initial pressure is provided solely by a restraining plate that equalizes a distribution of the initial pressure;   impacting a region of the package with a force sufficient to create a disturbance to the package while not destroying the package, wherein the impacting is performed by an impactor, wherein the impacting is performed only for a period of time that is on the order of milliseconds;   detecting a force signature from the impacting of the region of the package at a location a distance from the region of the package using a sensor; and   determining an existence of a leak by evaluating an output of the sensor,   wherein the sensor is in direct, physical contact with the package when the force signature is detected, and   wherein the sensor is physically separated from the impactor.   
     
     
         2 . The method according to  claim 1 , wherein the impactor is an impacting rod, wherein impacting the region of the package comprises dropping the impacting rod onto the region of the package so as to impart an approximately vertical blow on the region of the package, and wherein, during the impacting, the impacting rod is in direct, physical contact with the package only for a period of time that is on the order of milliseconds. 
     
     
         3 . The method according to  claim 1 , wherein the sensor comprises a transducer. 
     
     
         4 . The method according to  claim 3 , wherein detecting the force signature from the impacting of the region of the package comprises contacting the package with four transducers disposed equidistant from the region of the package having the impact, and receiving a sensing signal from each of the four transducers through corresponding charge amplifiers. 
     
     
         5 . The method according to  claim 1 , wherein determining the existence of the leak by evaluating the output of the sensor comprises:
 comparing the output of the sensor after the impacting of the region of the package to stored signals or values representing a good seal.   
     
     
         6 . The method according to  claim 1 , wherein the initial pressure is applied to the package in a direction parallel to the direction of the impacting to the region of the package from the impactor. 
     
     
         7 . A system for leak detection of a package, comprising:
 a sensing surface for receiving a package;   a plurality of sensors on the sensing surface;   a restraint for solely providing an equalized initial pressure to the package;   an impactor, wherein the impactor imparts an impact to a region of the package; and   a processor receiving an output signal from each sensor, evaluating dynamic force signatures from the output signals, and comparing the output signal of each sensor to that of each other sensor,   wherein the system is configured such that the each sensor is in direct, physical contact with the package during use.   
     
     
         8 . The system according to  claim 7 , wherein each sensor comprises a transducer. 
     
     
         9 . The system according to  claim 7 , wherein the system is in-line with packaging a product. 
     
     
         10 . The system according to  claim 7 , wherein the impactor comprises an impacting rod. 
     
     
         11 . A method of leak detection of a package, the method comprising:
 providing an initial pressure to the package, wherein the initial pressure is provided solely by a restraining plate that equalizes a distribution of the initial pressure;   impacting a region of a package with a force sufficient to create a disturbance to the package while not destroying the package;   detecting, by a plurality of sensors, a change in pressure caused by the impacting of the region of the package; and   determining an existence of a leak using the change in pressure,   wherein determining the existence of the leak comprises:   comparing characteristics of output signals of each sensor of the plurality of sensors to each other, wherein the characteristics include at least one of amplitude, decay, duration, and shape.   
     
     
         12 . The method according to  claim 11 , wherein the impacting is performed by an impactor, wherein the impacting is performed only for a period of time that is on the order of milliseconds. 
     
     
         13 . The method according to  claim 12 , wherein the impactor is an impacting rod, wherein impacting the region of the package comprises dropping the impacting rod onto the region of the package so as to impart an approximately vertical blow on the region of the package, and wherein, during the impacting, the impacting rod is in direct, physical contact with the package only for a period of time that is on the order of milliseconds. 
     
     
         14 . The method according to  claim 11 , wherein each sensor of the plurality of sensors comprises a transducer. 
     
     
         15 . The method according to  claim 14 , wherein detecting the change in pressure caused by the impacting of the region of the package comprises contacting the package with four transducers disposed equidistant from the region of the package having the impact, and receiving a sensing signal from each of the four transducers through corresponding charge amplifiers. 
     
     
         16 . The method according to  claim 12 , wherein the initial pressure is applied to the package in a direction parallel to the direction of the impacting to the region of the package from the impactor.