The sealing integrity and/or the proper filling of sealed packages is determined by conveying them continuously along a path and applying loads to them. The loads have package contacting surface portions that travel in the conveying direction, e.g., provided by driven belts or arrays of free-running rollers. Preferably each package is subject to a first load and to a second load greater than the first, and two values related to the effective package thickness under the loads are derived and compared by a computer system. The difference value is indicative of package seal quality.
Packages (7) are conveyed through at least one, and preferably two, test stations (14, 16). At each station there is a test head (7) which is urged towards the conveying path, preferably by gravity. As a package (7) is conveyed through a station it displaces the head away from the path. The displacement is monitored. Preferably, subsequent displacement towards the path due to leakage of the package is also monitored.
A method and work station (SV) for checking the integrity of packages (2), in particular single-dose packages uses a first pressing device (4) for applying a reference force to one or a group of packages (2) for a predetermined time interval (Dt). The value of the force transmitted by the package (2) is detected using one or more load cells (6) positioned opposite to the first pressing device (4) with respect to the package (2). The load cells detect the force transmitted through the package. Packages are rejected when the value of the force transmitted by the package (2) is lower than a critical force value (f*) which is a value of the force transmitted to the load cells by a good package. Before using the first pressing device for applying the reference force, a second pressing device is used to apply a test force to the package (2) for a time interval (Dt*) for preliminarily stressing the package (2) before the load cells detect the value of the force transmitted by the package (2) in response to the force applied by the first pressing device.
A method and apparatus for leak testing a closed container having a substantially flexible wall structure wherein a compressive force is applied to the wall structure such that the wall structure is displaced from a first position to a second position. The compressive force is maintained for a pre-determined first period of time to stabilize the container wall structure. After the stabilization period, the compressive force is released wherein the wall structure commences recovery from the second position toward the first position. The wall structure recovery from the second position is measured at a pre-determined second period of time.
A method of and apparatus for testing for leaks in a package is provided. The package is compressed under the weight of a test element (16). The position of the test element is measured at least twice and the positions are compared to check movement of the test head due to gas or liquid escape from the package.
A seal checker capable of reliably detecting a faulty seal at a vertical seal portion of a packaging bag or a portion thereof covered by the vertical seal portion is provided. A lower transfer conveyor conveys a packaging bag such that a vertical seal portion thereof moves along the conveyance direction. The upper and lower transfer conveyors sandwich and press the packaging bag therebetween. A servo motor detects the distance between the transfer conveyors when the packaging bag is pressed thereby. A control unit determines the seal properties of the packaging bag based on the distance detected by the servo motor. A gap is provided on a conveyance surface of one of the transfer conveyors to which the vertical seal portion faces, which extends in the conveyance direction and prevents the vertical seal portion from being pressed.
