AU600527B2 - Method and apparatus for detecting holes in flexible containers - Google Patents

Description

AUSTRALIA 6 00,'52 7 Patents Act COMLETE SPEC1 ICATION (ORiu INAL) Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted-, Published: IPriority Iamendincfls =-Odc 1nd.r SeCCtofl 49 Wit, rrcLt for printing Related Art: APPLICANT'S REF.: Name(s) of Applicant(s): AS5VRA PHARIACEUTICALS PTY. LTD.

00 04 0 Address(es) of Applicant(s), Actual Inventor(s): P.O. Box 31, North Ryde, New south Wales Au~stralia MICHAEL KIMBER 2113 PETER ALFRED LUJBLIN 0 0 0 0 Address for Service is: PHILLIPS, ORMONDE AND FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne, Australia, 3000 Complete Specification for the invention entitled: METHOD AND APPARATUS FOR DETECTING HOLES IN FLEXIBLE CONTAINERS The following statement is a full description of this Invention, including the best method of performing it known to applicant(s): P19/3/84 This invention relates to a method and apparatus for detecting holes in flexible packages containing fluids.

Whilst not so limited this invention is of particularly useful application in detecting leaks in plastic ampoules. In the past it has been the normal practice to package parenterals and other pharmaccatically useful fluids in glass ampoules. However, aseptic methods have in recent times been developed enabling some parenterals to be packaged in plastic ampoules. Such packaging is usually manufactured from polyethylene or polypropylene although other polymers may be used. The advantages of such packaging are self apparent.

0 o0 The most serious disadvantage of glass is the possibility of breakage exposing the person using the ampoule to risk of 0oo 0 0 0 Sinjury. The consequences of such breakage can be dire as o 0 0 0 0 o these ampoules are often used in situations which require the 0 0 o 1 utmost safety, for instance, in operating theatres.

Injectables such as Xylocaine (trade mark), irrigation solutions and nebuliser diluent are examples of 0 t some of the parenteral solutions which can now be aseptically 0000 0 0 4 o00 packaged in plastic ampoules. However it is imperative that when such ampoules are used that they be tested and checked 0000 o0 o after filling to ensure that the contents remain sterile. A 00 00 So 0 major risk of contamination is the ingress of contaminating materials through holes in the plastic package. Small holes in such plastic ampoules can be difficult to detect but can result in the package no longer remaining aseptic.

In the past it has been proposed and practiced to test plastic ampoules for holes after they have been filled by immersion in coloured dyes whilst held under pressure. These 2 -3tests are cumbersome and have been found useful in detecting holes only in the order of 10 to 20 microns in diameter.

An object of the present invention is to provide an improved method for detecting holes in flexible packages containing fluids. It is another object of this invention to provide apparatus useful in utilizing the method of the invention.

The method according to the present invention provides a method for detecting holes in two or more flexible packages containing fluids comprising the steps of conveying said fluid containing flexible packages to a pressure testing zone; stopping and aligning said packages beneath respective pressure applying elements which are spaced apart from each other for the application of respective forces to each of said packages; fill ,9 simultaneously applying a force to a wall of each of the said packages by means of said force applying elements wherein said force is sufficiently high to cause deformation of the package wall but less than that which would cause said packages without holes to rupture; maintaining said force against each said package for a period of at least 5 seconds; releasing said force from the walls of the packages and thereafter conveying the said packages to an inspection zone; and S(f) inspecting the packages for moisture on the surface thereof or deformation due to displacement of air indicative of the existence of a hole in the said package or packages.

i Ct 3a Preferably the force is applied to the package by an element of approximately the same diameter as the diameter of the package heing tested. Using the method of the invention it is possible to test a number of packages simultaneously.

When more than one package is tested at the same time the force is applied to the walls of the packages individually by separate elements adapted to apply a force to each respective package, Separate pressure applying elements are utilized for each respective package being tested at the same time.

Of course a single bar could be utilized if it comprised protrusions or heads which could in effect operate as separate elements. Preferably, the force is applied to the package at a point approximately midway along the length of 0 0 0 0 0000 00 0 0 0 0 a 00 00 0 OO 00 0 0 0 0000 0 0 00 0000 0 00 00 O OC 490 C t S t t 0 C i .iJi~

L

4 the package.

The apparatus according to the present invention comprises:a conveying means for conveying fluid containing flexible packages to a pressure testirg zone; at least two force applying elements each adapted to simultaneously apply and maintain for a period of at least seconds a force sufficiently high to cause deformation of said package but less than that which would cause packages without holes to rupture wherein said force applying elements are spaced apart from each other for the application of respective forces to each of a number of flexible packages; aligning means adapted to stop and align said packages beneath the respective pressure applying elements; an inspection zone suitable for allowing inspection of o0 OOO 0 the packages subsequent to the application of the forces 0o applied thereto by the force applying elements; and o 00 conveying means for conveying said packages from said 00 000 pressure testing zone to said inspection zone.

0, The conveying means may be of any type known in the art. Typically, a rubber or plastic conveyor belt is utilized. A grid type plastic belt is preferred so that if any package leaks or is ruptured the liquid containing therein will be able to drain off the conveyor belt system.

Utilizing the apparatus of the present invention, it is possible to test more than one package simultaneously.

Preferably, the apparatus of the present invention is constructed so to test at least 10 or more packages simultaneously. In such a construction, there is provided a suifficient number of force applying elements so that each package can be simultaneously subjected to a force by a separate element. The force applying element may be of any shape but is preferably cylindrical. Each element has a contact portion which is adapted to come into contact with a wall of the respective package to which pressure is to be applied. The contact portion is preferably of a hemispherical shape so to reduce the possibilit7 of the force applying element puncturing or otherwise rupturing the A' AN package to which pressure is to be applied.

I The force applying elements can be actuated by any of a number of different methods known in the art.

Preferably, they are pneumatically actuated. However, hydraulic or mechanical means may be utilized to provide the desired force. The force applied by the force applying element to the wall of the package should be sufficiently high to at least cause deformation of the package wall but must be less than that which would cause a good or unpunctured package to rupture. Most preferably a force is applied which w.ll result in the intecnal pressure of the package being approximately 100 kPa.

The apparatus of the present invention is particularly useful when used in conjunction with a fully automated labelling and packaging line. The spacin- of the packages being tested similtaneously and the spacing of the force elements is important. It is important that the apparatus be arranged so that the packages convtyed to the pressure applying zone are stopped and aligned beneath the respective pressure applying elements. This ensures that the contact portion of the element will apply the desired force to the package wall. The forge applying elements may be arranged to apply a force to the packages at any point along their length. Most preferably the, are arranged so that the contact portion applies a force at a point approximately midway along the length of each respective package.

In one embodiment of the invention the apparatus includes a retractable gate adapted to stop a package immediately beneath a force applyinig element as the package is being conveyed into the pressure applying zone. This gate can 5 i Y j i i be activated by a number of different methods known in the art. It has been found that use of a photoelectric eye positioned above or alongside the conveying means is an effective instrument for this purpose. The photoelectric eye detects the passage of the package into the pressure applying zone and activates the retractable gate so that it blocks the passage of the package beyond a certain point within the pressure applying zone. When a number of packages are being tested similtaneously the gate is activated so to block the progress of the first of the packages to enter the pressure applying zone. The other packages are prevented from moving o further along the conveying means by the package immediately °o before them. The packages in this way abut tip one against the 0 0 Soo other. The pressure applying elements are arranged in this 00 o o oo embodiment such that the mid points of adjacent elements are 00 0 0 separated by a distance equal to the diameter of the packages being tested. This ensures that the contact portion of the respective pressure applying element is positioned immediately above the respective package to be tested.

In a further embodiment rather than utilizing a retractable gate the conveying means is fitted with flights which separate distinct sections of the conveying means. The sections are spaced so that they fit a specified number of packages therebetween. The conveying means conveys the packages to be tested into the pressure applying zone and the conveying means is arranged such that a flight will stop at a predetermined position relative to the force applying elements. This enables accurate positioning of the packages underneath the force applying elements. Preferably holding S-

I

means are also provided to hold the packages firmly against one of the flights whilst the packages are in the pressure applying zone. Such holding means can conveniently be provided by rubber strips positioned above the pressure applying zone and adjacent to a position where a flight has been arranged to stop.

Following the application of a force on the package or packages by the for.;e applying elements the packages are conveyed out of the pressure applying zone to an inspection zone. This inspection zone is preferably well lighted so that the packages can easily be examined. Inspection may be o conducted by electronic means but it is found that inspection ooo can more conveniently be conducted by eye. Holes in packages 0 0 0 can be detected by the existance of moisture on the outside of 0 04 Q0 Q the container or by loss of air which results in deformation of the package.

The method and apparatus of this invention enables detection of very small holes in plastic packages. The inventors have found the method and apparatus useful in 0004 .O 1 detecting holes in plastic packages as small as 2 to 3 microns.

Soo a This invention is further described by reference to Oa 00 0" preferred embodiments as shown in the accompanying drawings in Swhich:- Figure 1 is a perspective view of an apparatus made in accordance with the present invention.

Figure 2 is a perspective view of the apparatus shown in Figure 1 with plastic ampoules positioned underneath force applying cylinders.

7- Figure 3 is a perspective view of the retractable gate positioned at one end of the apparatus shown in Figure 1.

Figure 4 is a perspective view looking I along the conveyor belt towards the pressure applying zone.

Figure 5 is a perspective view of a further embodiment of an apparatus made in accordance with the invention.

In Figure 1 there is shown a conveyor belt 1 made from a rigid plastic material, for conveying plastic packages to a pressure applying zone 2. The conveyor belt 1 is of a o grid configuration which allows any liquid spilt onto the belt o000 0 to drain off its top surface 3. A frame 4 supports a number 00o0 of pneumatically operated cylinders 5 situated immediately a 00 0o above pressure applying zone 2, The cylinders 5 have contact 00 0 0000 portions 6 which are of rounded or hemispherical shape.

Cylinders 5 are adapted to move downwards towards conveyor 00 S'oo belt 1. They are operated pneumatically and pressure lines 6A o 00 .o000 are connected to the top of cylinders 5 to provide the Soooo appropriate motive force.

A photoelectric eye 7 positioned above the conveyor belt 1 electronically activates a retractable gate 8 (shown in j 0 0 I 0 Figure 3) when a plastic ampoule is detected moving past a predetermined point of the pressure applying zone 2. The retractable gate 8 is hinged so that when it is activated by the photoelectric eye 7 it effectively blocks the path of the conveyor belt 1.

In operation a number of plastic ampoules 9 (shown in Figure 2) previously accumulated are conveyed on their sides by conveyor belt 1 to pressure applying zone 2, As the -8 ii i i -I first of these ampoules 9 passes under photoelectric eye 7 an impulse is generated which activates a piston 10 which in turn pushes retractable gate 8 across the path of conveyor belt 1.

When the first of the plastic ampoules 9 reaches retractable gate 8 its path is blocked so that it cannot move further 'through pressure applying zone 2. Subsequent amnpoules abut up against the ampoules immediately before them. The conveyor belt is then stopped (either manually or remotely) The positions of cylinders 5 and retractable gate 8 are arranged such that each cylinder 5 is directly located above a respective ampoule 9 when they have been stopped by retractable gate 8. Once the conveyor belt 1 has stopped and the ampoules 9 have been located beneath the cylinders 5 the cylinders are pr Numatically activated so that they move downwardly torwards the ampoules 9, Contac. portions 6 coact against the approximate centre of the side walls of ampou,,zes 9 applying a force which results in an increased internal pressure within each of the ampoules 9, £r plastic apue manufactured of polyethylene having walls 0.6 mm thick it has been found that it is preferable to apply a pressure which will result in ampoule internal pressure of approximately 100 kPa. For ampoules having an external diameter of 25 mm i t has been found necessary to provide a line pressure of approximately 600 kPa to provide zsu, h an internal pressure.

For amopoules having an external diameter of 17 miin it has been found necessary to provide a line pressure of approximately 400 kPa to provide such an internal pressure, Clearly the optimum pressure varies dependent on a number of different factors including the nature of the material from 9which the package is made, its thickness and the shape and diameter of the package being tested. The force applied by the cylinders is maintained for a short period of time preferably in the order of 5 to 20 seconds. The line pressure is released after this time and the cylinders are biased so that they return to a position above the ampoules being tested. The conveyor belt 1 is then restarted (again either automatically or manually) and the ampoules 9 are conveyed to an inspection zone (not shown). At the inspection zone the ampoules are inspected as to any possible leakage. A hole or open pore is easily identified by either moisture appearing on oo the surface of the ampoule or deformation of the ampoule o oo oooo evidencing loss of air. Ampoules inspected exhibiting either 0 0 o 0a" of these characteristics can be discarded as potentially 0000 0 0 0 0 S000 containing a fluid which is no longer aseptic, In the embodiment illustrated in Figure 4 the conveyor belt 1 includes flights 11. These flights are spaced 0 0o so that they can hold a predetermined number of ampoules 9.

0 00 In the embodiment illustrated the flights are spaced so to 0 0 0 o seat 6 ampoules therebetween. Unlike the embodiment shown in r Figures 1 to 3 there is no retractable gate or photoelectric o, eye required to position the ampoules 9 directly below the at 44 S' e respective cylinders 5. This positioning is effected by the conveyor belt 1 being arranged to stop with a flight A adjacent the end of the pressure applying zone 2 or any other predetermined position which ensures that the ampoules 9 are positioned directly beneath the respective force applying cylinders 5. Rubber fingers 12 apply pressure to the top of the ampoules 9 to hold them firmly against the side of one of 10 i .Y i_ 0 a 0 0 0 000 00 O0 00 0 O 00 0 0 0 00 00 0 0 0 0 000 the flights 11. This ensures correct location of the ampoules 9 beneath the cylinders 5. In the embodiment shown the ampoules 9 between the respective flights 10 are joined together and the rubber fingers 11 apply force to the end ampoule only, As each of the ampoules are connected between a set of flights 10 the position of the ampoules can be accurately located. In this embodiment force application and inspection is conducted in a similar manner as that as described hereinbefore.

In order to test the efficiency of this process in detecting small holes in plastic ampoules or other packages a number of tests have been carried out by testing filled packages with artificially created holes. These tests were conducted on polyethylene ampoules.

The first step in these tests was to create an atificial but small hole, The method utilized was to pressurize the ampoules either in a pressure test-rig or in a vice and to very slowly offer an acupuncture needle to the wall of the ampoule. Pressure was applied to the needle until the first drop of fluid was Visible, The area of the punt 1 was then marked.

The punctured ampoule was placed in a testoo-rig identical in operation to the pneumatic cylinder testing apparatus as described hereinbefore. A line presOure of 600 kPa (resulting in an internal pressure of approximately 100 kpa) was applied to the cylinder which squeezed the ampoule ait approximately the mid point of its side until it leaked, The ampoules were numbered I marked and submitted for ex.

by electron miroascopy This examination involve S- II 00 0 10t8 0 C f i1-" ii i I of platinum around the area of the hole, photographing the image and applying a camera factor to the microscopy magnification. The results are shown in Table 1.

2j 12

J

I

TABLE 1

OQOC

0 00~ 0 0 00 0 00 0 00 Q 0 0 No.

1 2.

3.

4.

6.

7.

00 0 8.

'0 0 0 9.

0 0 0 00 C,0 10.

11.

004 12.

13.

14.

16.

17.

18.

0 19.

21 22.

23.

24.

MEASUREMENT OF HOLES CAUSING LEAKS IN PLASTIC AMPOULES Leak Time* Hole Size (urn) Ampoule Size Yes 145 x85 Yes 126 x 73 Yes 100 x 73 Yes 72 x 34 Yes 100 x 87 Yes 100 x 83 Yes 93 x 97 Yes 84 x Yes 93 x 97 Yes 80 x67 Yes 87 x 73 Yes 68 x 70, 67 x 73 Yes 44 x 19, 44 x 18 Yes 70 x 64 2 mL Yes 72 x74 i Yes 26 x 33 i Yes 83 x83 i Yes 160 x 80 o Yes 58 Yes 67 Yeas 83 x73 Yes 50 Yes 57 x63 Yes 67 x47 Yes 90 x63 00 0 0 0 13 -i 26. Yes 100 x 73 27. 120 No hoj.e found 10 mL 28. 120 No hole found 5 mL 29. 120 No hole found 5 mL Yes 19 x 12 10 mL 31. Yes No hole found 5 mL 32. Yes No hole found 5 mL 33. Yes No hole found 5 mL 34. Yes 18 x 13 Yes 30 x 36. Yes 2 x 3 0 37. Yes No hole found 0° 38. Yes 13 x 9 00 0 o o0 39. Yes 14 x 0 0 0 00 40. 13 23 x 1 00 00 0 41. 60 No hole found 42. Yes 13 x 18 43. Yes 28 x 43 44. Yes 58 x 32 Yes 66 x 36 46. Yes 32 x 21 47. Yes 13 x 9 S, 48. 60 No hole found 49. Yes 57 x 57 Yes 14 x 4 51. Yes 62 x 36 52. Yes 50 x 14 53. Yes 200 x 27 54. Yes 66 x 14

F

56.

57.

58.

59.

61.

62.

63.

64.

66.

67.

68.

69.

71.

Leak: Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes 58 15 165 80 107 15 93 80 76 133 100 123 163 167 103 130 97 x 34 x 9 x x 67 x 77 x x 43 x 73 x x x x 100 x 63 x 57 x 86 x 73 x 0000 000 o 0 0000 0 0 oo 0 00ooo0 0 00 0oo0 n0 0o oo0 0 000 o0 O0 0 If a leak was detected in less than 10 seconds this is indicated by the word "Yes". If a leak occurred in greater than 10 seconds the period of time (in seconds) for which pressure was applied is indicated.

15 In some of the ampoules tested leakage was detected, where subsequent electron photography failed to disclose a hole. It is thought that in these cases the holes may have been occluded during the platinum plating process.

In six instances leakage did not occur within the second test time. Pressure was maintained for 60 seconds in two cases until a drop of liquid was noticed and for 120 second in three cases until liquid was noticed. In none of these cases was it possible to detect a hole. In the sixth case of failure to leak in the test period, leakage took place at approximately 13 seconds; electron microscopic examination f showed that the needle had not penetrated completely leaving a flap which apparently closed again on becoming pressurized.

This failure is seen as a product of the piercing process and not of the leak testing system.

The results show that except for the six cases discussed above the drops were detected within a 10 second test period. Many hole sizes were relatively large and therefore of little interest in establishing a comparison with the conventional pressure dye solution leak testing method.

However there were a sufficient number of small and extremely small holes to establish this method of leak testing as at least comparable if not more searching than the dye test. In 4" Figure 6 there is shown a photograph of the hole artificially created in test number 36. This hole was only 2 microns wide and 3 microns long. The method and apparatus of the invention enabled detection of this hole in a test period of less than seconds.

The apparatus and method disclosed can conveniently 16 be placed in an automated filling and labelling process line, is found to be at least as searching as earlier methods and less cumbersome.

Finally, it is to be understood that various alterations modifications and/or additions may be introduced into constructions and parts previously described without departing from the spirit or ambit of the invention.

I e It 4 17

Claims (11)

1. 2. A method as claimed in claim 1 wherein at least scime of the respective packages are joined together.
2. 3. A method as claimed in any one of the previous claims wherein the force applying elements each have a diameter approximately equal to the diameter of the fluid containing flexible packages.
3. 4. A method as claimed in any one of the previous claims wherein the force is applied to the package at a point approximately midway along the length of the package, An apparatus for detecting holes in two or more flexible packages containing fluids comprising:- a conveying means for conveying fluid containing flexible packages to a pressure testing zone; I -~izic_ 19 at least two force applying elements each adapted to simultaneously apply and maintain for a period of at least seconds a force sufficiently high to cause deformation of said package but less than that which would cause packages without holes to rupture wherein said force applying elements are spaced apart from each other for the application of respective forces to each of a number of flexible packages; aligning means adapted to stop and align said packages beneath the respective pressure applying elements; an inspection zone suitable for allowing inspection of the packages subsequent to the application of the forces applied thereto by the force applying elements; and conveying means for conveying said packages from said pressure testing zone to said inspection zone. "r _j .r i -i and adapted to do so simultaneously; an inspection zone suitable for allowi'g-r spection of the packages subsequent to the-a-plrlcation of the forces applied thereto by the-f-o-ce applying elements; and conveying means for conveying said packages from said Sp-r-essure testing zone to said inspection zone.
4. 6. An apparatus as claimed in claim 5 wherein the force applying elements are positioned above the pressure testing zone and wherein the conveying means is adapted to transport the respective packages being tested to positions in the pressure testing zone aligned directly beneath each of the respective force applying elements.
5. 7. An apparatus as claimed in either one of claims 5 or 6 wherein the respective packages are aligned by means of conveyor belt flights spaced so to fit a specified number of packages therebetween and wherein the conveyor belt is caused to stop in the pressure testing zone at a predetermined position of conveyor belt flights relative to the force applying elements.
6. 8. An apparatus as claimed in any one of claims 5 to 7 wherein the force applying elements are substantially cylindrical and of a diameter approximately equal to the diameter of the package to which a force is to be applied.
7. 9. An apparatus as claimed in any one of Claims 5 to 8 wherein the force applying elements are pneumatically actuated, An apparatus as claimed in any one of claims 5 to 9 wherein the force applying elements are positioned such that upon actuation the said force applying elements apply a force at a point approximately midway along the length of each of the respective packages being tested,
8. 11. An apparatus as claimed in any one of claims 5 to wherein the respective packages are aligned by means of a retractable gate adapted to prevent the passage of packages beyond a specified point in the pressure testing zone and which causes the packages to be positioned beneath each of s.t the respective force applying elements,
9. 12. An apparatus as claimed in claim 11 wherein the 0- -c LL r i i retractable gate is activated by means of a signal generated by a photoelectric eye positioned so to detect the introduction of a package into the pressure testing zone.
10. 13. A method for simultaneously detecting holes in two or more flexible packages containing fluids substantially as hereinbefore described with reference to what is shown in the drawings.
11. 14. An apparatus substantiall.y as hereinbefore described with reference to what is shown in the drawings. DATED: 12 May, 1989 PHILLIPS ORMONDE FITZPATRICK Attorneys for: ASTRA PHARMACEUTICALS PTY, LTD. d I 7 <C, t c. 2t I- I I, -e