WO2001088503A1

WO2001088503A1 - Testing device for closed seam of sterilized package

Info

Publication number: WO2001088503A1
Application number: PCT/FI2001/000475
Authority: WO
Inventors: Raino Ahokas
Original assignee: Raino Ahokas
Priority date: 2000-05-16
Filing date: 2001-05-16
Publication date: 2001-11-22
Also published as: FI109834B; FI20001168A; EP1290426A1; AU2001260375A1

Abstract

The invention relates to a device for testing a sealed seam of sterilization packaging. A testing device formed in accordance with the invention comprises a frame (2), a unit of mass which is movable on a vertical plane (6) and located on the frame, one or more means of fastening (12), located on the unit of mass and/or on the frame, which is used for fastening the sample, and a conveying device used for moving the sample and/or the unit of mass in relation to one another, whereupon the sealed seam can be tested by fastening the sample, which includes the sealed seam, to the means of fastening and by putting strain on the seam using the unit of mass.

Description

TESTING DEVICE FOR CLOSED SEAM OR STERILIZED PACKAGE

The invention relates to a device for testing sealed seams on sterilization packaging, and, in particular, a device for testing the sealed seams of bag-like packaging used for sterilizing hospital instruments, as well as for testing the condition of the sealers.

In hospitals and health care establishments, multi-purpose hospital instruments are always sterilized before use. Sterilization generally transpires in a device called an autoclave, using pressurized, saturated steam. In order to prevent the instruments from getting re-contaminated by the microbes in the surrounding air, before they are sterilized, they must be packed in sterilization packaging, thus the packaging protects the instruments from being contaminated after sterilization. The packaging, therefore, must be permeable to steam, so that the steam can get inside the packaging to make contact with the instrument and destroy the microbes. Modern sterilization packaging is bag-like in structure, and such that one side of the bag is permeable so-called medical paper, and the other side is laminated plastic. These materials are joined to one another using heat and pressure into a bag-like packaging, which is sealed on three edges at the factory. One of the edges is left unsealed, so that the user can put the instrument inside the bag. At health care establishments, the instruments are disinfected, serviced and then packaged for sterilization. The packaging is done manually. After the instrument is packaged, the bag is sealed using a special heat sealer developed for the purpose. Sterilization in the autoclave is ensured, such that air is removed from the load of instruments to be sterilized by first creating a vacuum in the sterilization chamber, and then feeding steam into the chamber, simultaneously converting the underpressure into overpressure. The underpressure-overpressure-underpressure cycle is consecutively repeated a few times and causes the pressure inside the packaging to vary accordingly, in proportion to the surroundings. The bag expands and shrinks in turn. The seams of the packaging must therefore be able to withstand great strain during sterilization. Likewise, hospital instruments or instrument sets gathered for an operation can be very heavy and seams are therefore subjected to great amounts of strain. The endurance of the bag's sealed seam would have to be assured earlier, in the phase when the packaging was being carried out and the sealed seam was being made. Requirements for the sealed seams of sterilization packaging are presented, for example, in sterilization packaging standards EN 686 or DIN 58953.

A problem with the current practice is that the condition of the heat sealers being used cannot be assured sufficiently comprehensively and reliably; sealing transpires using seam sealing parameters which are in accordance with the instructions of either the sealer manufacturer or of the packaging manufacturer.

Packaging from different manufacturers, however, is sealed in different ways, likewise, sealers from different manufacturers function in different ways. Additionally, the individual maintaining the instruments can, in practice, only affect the heat during sealing. Neither the sealing pressure nor sealing time can be adjusted in modern sealers. The condition of the sealer can be checked intermittently, for example, twice a year, and the device can be validated by hospital maintenance personnel or by an external expert, however, thousands of packages are normally sealed in between these validations, so the strength of their seals remains unknown. That is to say, daily inspections of the operating condition of heat sealers are not currently being done, thus, the reliability of the seal on sterilization packaging is largely based on faith. Furthermore, it is necessary to recognize that joining plastic and paper to one another to yield a strong heat seal is not an easy task for someone who is not familiar with the manufacture of packaging, even if the sealing device is modern.

The three sides of the sterilization packaging, which are sealed at the factory, are tested by the manufacturer in a way, which is required in the manufacture of the products in question. The manufacturer of the packaging is naturally the best expert, and sealing or the control of the sealing normally doesn't present problems for them. The manufacturer uses certain machinery, certain raw materials and certain parameters for manufacture, and knows the right combination to ensure good products which comply with requirements. However, the manufacturer's responsibility ends when a health care facility begins to use the products. The user must then be prepared to test the properties of the last seam to be made, since the user is the one to make it.

Manufacturers of sterilization packaging use a pulling device to test the strength of the seam, with which other mechanical properties, besides the tensile strength, of different samples can also be tested, such as strain and elasticity. Some known trade names of such devices are Instron and Lloyd. These devices yield test results with precise absolute measured values. These devices are, however, very expensive devices, intended for laboratory and research use, and can under no circumstances become standard equipment for instrument maintenance in hospitals. Furthermore, methods have been developed for testing the condition of sealers, whereby faults in the sealer, for example in the pressing force or temperature, are revealed. The trade name of one such method is Hawotest-Seal Check. These methods are based, however, on the seam being visually evaluated after the test. Neither relative nor absolute strength can be tested using these methods.

The object of the invention is to provide a testing device, whereby the preceding presented disadvantages associated with current devices will be eliminated. In particular, the object of the invention is to provide a testing device, by which a quick and reliable seam test can be obtained, by which the strength of the seam can be judged and, at the same time, by which the condition of the heat sealer used for sealing can be determined for the moment that the seal was made. A further object of the invention is to provide a testing device, which is advantageous to produce and obtain.

The object of the invention is accomplished by a testing device, the characteristics of which are presented in the claims.

A testing device formed in accordance with the invention comprises a frame, which is joined onto a base, a unit of mass located on the frame and which is movable on a vertical plane, a means of fastening located on the frame and/or unit of mass for fastening the sample, and a conveying device for moving the sample and/or unit of mass in relation to one another. Thus, the sealed seam can be tested by fastening the sample to the means of fastening and using the unit of mass to put strain on the sample. The sample can be tested by lowering the unit of mass downwards after fastening the sample and then releasing it back up towards the sample. Alternatively, the sample can be tested by moving it upwards after it has been fastened, and by releasing the unit of mass from its position. A unit of mass of the appropriate weight is selected, such that, if the test sample withstands the strain from the unit of mass, the seam is in accordance with requirements.

This action is based on the load brought about by the gravity. This is brought about by a separate, precisely weighted unit of mass, which produces or exerts strain on the sample being tested, and the amount of which meets the standard requirements or other demands. The unit of mass is smoothly released by the conveying device in the testing device towards the sample being tested, whereupon faulty test results occurring from sudden strain are avoided. The testing device yields a quick, easy and reliable seam test, by which the strength of the seal can be judged in relation to the requirements set for strength, and thereby, further, a judgment can be made as to the condition of the heat sealer used for the sealing at the moment the seal was made. A device formed in accordance with the invention is also simple in structure and advantageous to produce and obtain. In an advantageous application of the invention, the testing device comprises a conveying device to move the sample in relation to the unit of mass. In this case, the sample is moved upwards by the conveying device until the unit of mass is supported by the sample. Thus, reliable test results are obtained.

In a second advantageous application of the invention, the testing device comprises a conveying device to move the unit of mass in relation to the sample. In this case, the unit of mass is moved downwards by the conveying device until the unit of mass is supported by the sample. Thus, again, reliable test results are obtained.

In many cases, standards set by the user for the strength of the seam are higher than those that are required. In a certain advantageous application of the present invention, it comprises one or more separate supplemental units of mass, which are fastened to the main unit of mass in a way known as such, and, for example, with a magnetic fastener. Thus, loads used for testing can be added easily and quickly.

The invention will now be described in more detail, with reference to the accompanying drawing, in which

Figure 1 illustrates a side and cross-sectional view of a sterilization packaging, and Figure 2 illustrates a side view of a testing device formed in accordance with the invention,

Figure 3 illustrates a frontal view of a testing device formed according to Figure 2, and Figure 4 illustrates an enlarged detail X from Figure 2.

Figure 1 illustrates a certain sterilization packaging 15. In manufacturing it, the sides of the bag are joined together with a factory-made seam 16. The manually sealed seam 17 is at the other end of the packaging. The figure illustrates a test sample 14 taken from the factory-made seam and an illustration of the test being done on it, performed by its being pulled in opposite directions.

The measurement of the seam strength of the sterilization packaging 15 taken so that it is in compliance with standards, such as those in German DIN 58953, is carried out, such that a sample clipping 14 of a certain length is cut from the seam in the way shown in Figure 1. According to the mentioned standard, the width of the sample clipping should be 15 mm. The sample is fastened to the device with a special means of fastening, which is, in most cases, a compressed air clip. Then the sealed materials are pulled apart from one another. The previously mentioned measuring device, adapted for the purpose, registers the force used to pull apart the materials. A testing device according to Figures 2-4 is comprised of a frame 2, which is fastened to the base 1. The so-called conveying device, which, in this application, comprises a nut piece 3, with closely set inside threads, a conveyor screw 4 and guide bushing 5 for the conveyor screw, is fastened to the frame. Additionally, the testing device comprises a unit of mass 6 of a selected weight, which moves on a vertical plane, and its movement controls 7. On the lower end of the conveyor screw 4, which is screwed inside the nut piece 3 and placed inside the guide bushing 5, is the movable support 8 for the unit of mass, and on the upper end is a spindle 9. On the side of the unit of mass, there is another screw guide bushing 10 and holes 11 for the vertical movement controls 7 of the unit of mass. The controls are bar- like pieces. The unit of mass and frame comprise a means of fastening 12 for the test sample 14. In this application, the means of fastening is a screwing clip, but other means of fastening can be used in other applications. The strength of the seam can be compared to some other absolute strength value by fastening supplemental units of mass 13 to the unit of mass. They can be fastened in a way known as such, and, for example, using a magnetic fastener.

When using a testing device formed in accordance with Figures 2-4, the test sample 14 is placed in the means of fastening 12 while the unit of mass is in the upper position. The conveyor screw 4 is turned, whereupon the unit of mass 6, sitting on the support 8, is lowered downwards until it finally is supported by the test sample. The weight of the unit of mass is selected, such that, if the test sample withstands the strain caused by the unit of mass, the seam will be in compliance with requirements.

In another advantageous application of the invention, the unit of mass is connected to and supported on the frame of the testing device, such that the unit of mass can move freely in a vertical direction. In this application, the conveying elements of the conveying device are fastened to the sample and the sample is fastened to the unit of mass by the means of fastening. When testing the sample, it is moved upwards by the conveying elements, whereupon the weight of the unit of mass affects the seam and when moving the sample upwards, the unit of mass can move upwards to the sample, whereupon all of the weight of the unit of mass is supported by the sample. In this application, also, the weight of the unit of mass is chosen, such that, if the test sample withstands the strain caused by the unit of mass, the seam will be in compliance with requirements.

A test using the testing device formed in accordance with the present invention is carried out mainly with the same principles as are found in the previously mentioned German DIN 58953 standards, but instead of using the force of a machine to provide strain for the test, the force of gravity is used. When a unit of mass with a weight corresponding to the force which is in accordance with the standards for seam strength is set to strain the sample being tested using the testing device, it can be determined whether or not the strength of the seam is in compliance with the standards.

The invention is not limited to the advantageous applications presented. It can vary within the frames of the inventive idea established in the claims.

Claims

1. A device for testing sealed seams on sterilization packaging, characterized in that the testing device comprises a frame (2), a unit of mass which is movable on a vertical plane (6) and located on the frame, one or more means of fastening (12), located on the unit of mass and/or on the frame, which is used for fastening the sample, and a conveying device used for moving the sample and/or the unit of mass in relation to one another, whereupon the sealed seam can be tested by fastening the sample, where the sealed seam is, to the means of fastening and by putting strain on the seam using the unit of mass.

2. A testing device formed in accordance with Claim 1, characterized in that the testing device comprises conveying devices used to move the sample in relation to the unit of mass.

3. A testing device formed in accordance with Claim 1, characterized in that the testing device comprises conveying devices (3, 4, 5) used to move the unit of mass in relation to the sample.

4. A testing device formed in accordance with Claim 3, characterized in that the conveying device comprises a nut piece (3) fastened to the frame (2), and guide bushing (5), as well as a conveyor screw (4) attached to the unit of mass.

5. A testing device formed in accordance with Claim 4, characterized in that the conveyor screw (4) has been passed through the guide bushing (5) and the threads are located on the inside of the nut piece (3).

6. A testing device formed in accordance with Claim 4 or 5, characterized in that the conveyor screw (4) has a support (8) for the unit of mass on its lower end, and a spindle (9) on its upper end.

7. A testing device formed in accordance with any of Claims 4-6, characterized in that the unit of mass (6) has a screw control gasket (10) and holes (11) for controlling the vertical movement of the unit of mass.

8. A testing device formed in accordance with any of Claims 1-7, characterized in that the device comprises one or more supplemental units of mass (13), which are detachably fastened to the unit of mass.