Method for tightness control of a filling-sealing unit for containers, and filling-sealing machine

Abstract

A method for tightness control of a filling-sealing unit (1) for containers (9) is described. According thereto, a pressure chamber formed at the filling-sealing unit is sealed by way of a first seal around a sealer that is movable therein and by way of a second seal around a pressure supply that is movable therein. According to the invention, a third seal formed for sealing the pressure chamber around a container neck finish is sealed from the outside with an attachment, a positive pressure and/or negative pressure is generated in the pressure chamber, the pressure line used for this purpose is closed, and then a pressure profile in the pressure chamber is measured. This allows a leakage to be selectively detected at the first and/or second seal and be distinguished from a leak at the third seal.

Claims

1. A method for tightness control of a filling-sealing unit for containers, where a pressure chamber formed at said filling-sealing unit is sealed by way of a first seal against a sealer that is movable therein and by way of a second seal against a product feeder, wherein a third seal formed for sealing said pressure chamber around a neck finish portion and/or a neck portion and/or a shoulder portion of said containers is temporarily sealed from the outside with an attachment, thereby temporarily replacing the function of the third seal and an inserted container of said containers with the sealing attachment, a positive pressure and/or negative pressure is generated in said pressure chamber, a pressure line used for this purpose is closed, and then a pressure profile in said pressure chamber is measured, where a container is introduced with at least one of its neck finish portion, neck portion and shoulder portion into said third seal, where compressed air is provided to the third seal such that the same encloses the neck finish/neck/shoulder portion of the container in a liquid-tight and gas-tight manner in relation to at least one of a positive pressure and a negative pressure prevailing during working operation of the filling-sealing unit, and where at least one of the positive pressure and the negative pressure is generated in said pressure chamber, said pressure line used for this purpose is closed, and then a pressure profile in said pressure chamber is measured.

2. The method according to claim 1, where a test member simulating said neck finish portion, said neck portion, and/or said shoulder portion of said containers is introduced into said third seal, a positive pressure and/or negative pressure is generated in said pressure chamber, said pressure line used for this purpose is closed, and then a pressure profile in said pressure chamber is measured.

3. The method according to claim 1, where a positive pressure of at least 1 bar is generated.

4. The method according to claim 1, where said positive pressure is generated by introducing CO.sub.2.

5. The method according to claim 1, where a negative pressure of 0.1 bar or less is generated.

6. The method according to claim 1, where said pressure profile is respectively measured over a period of time of at least 0.5 seconds.

7. The method according to claim 1, where tightness control is performed on all filling-sealing units of a filling-sealing machine of a rotary type.

8. The method according to claim 7, where tightness control is performed for every filling-sealing unit at least twice consecutively with different containers.

9. The method according to claim 7, where said filling-sealing units are moved to a corrective maintenance point of said filling machine in case they fail said tightness control.

10. The method according to claim 7, where said tightness control is performed with said containers at a maximum rotational speed of said filling machine intended for production operation.

11. The method according to claim 7, where said tightness control is performed with said containers at a reduced rotational speed relative to normal production operation or at a standstill of said filling machine.

12. The method according to claim 7, where tightness control is performed several times during and/or between ongoing production operation and a trend analysis based thereon is created for said filling-sealing units controlled for tightness.

13. The method according to claim 1, wherein a CIP agent is passed prior to tightness control through said filling-sealing unit sealed with said attachment.

14. A filling machine of a rotary type with several filling-sealing units and with a programmable control unit for performing test runs following the method according to claim 1.

15. The method according to claim 1, where a positive pressure of at least 3 bar is generated.

16. The method according to claim 1, where said pressure profile is respectively measured over a period of time of at least 5 seconds.

Description

BRIEF DESCRIPTION OF FIGURES

(1) Preferred embodiments of the invention are illustrated in the drawings, where

(2) FIG. 1 shows a schematic longitudinal sectional view through a filling-sealing unit with a container;

(3) FIG. 2 shows a schematic representation of the filling-sealing unit with associated media lines;

(4) FIG. 3 shows a schematic top view onto a filling-sealing machine;

(5) FIG. 4 shows an operation chart of the method with variants of pressure monitoring; and

(6) FIG. 5 shows a schematic representation of a pressure profile measured.

DETAILED DESCRIPTION

(7) As is evident from FIG. 1, the filling-sealing unit 1 according to a preferred embodiment comprises a pressure chamber 2, sealer 3 movable therein, and a product feeder 4 movable in pressure chamber 2. Product feeder 4 and sealer 3 are known to be formed for a successive actuation from their resting positions to a filling position or sealing position, respectively.

(8) Sealer 3 is sealed by way of a first seal 6 against a housing of filling-sealing unit 1 surrounding pressure chamber 2. First seal 6 is, for example, a lip seal. Product feeder 4 is sealed against housing 5 by way of a second seal 7. Second seal 7 is, for example, a rubber-preloaded plastic seal.

(9) Seated in a lower portion 5a of housing 5 is a third seal 8 which is configured to receive and seal a neck finish portion 9a and/or an adjoining neck portion and/or an adjoining shoulder portion of a container 9 to be filled with a liquid product and to be closed. Third seal 8 is preferably formed as an elastic torus and, for example, made of suitable plastic material. Third seal 8 can be acted upon with compressed air to seal neck finish portion 9a, the neck portion and/or the shoulder portion. Neck finish portion 9a, the neck portion and/or the shoulder portion of container 9 can be enclosed by third seal 8 in a liquid-tight and gas-tight manner in relation to the prevailing positive pressures and/or negative pressures.

(10) Lower section 5a of housing 5 comprises a sealing seat 5b for third seal 8, where sealing seat 5b can shaped in a forcipate manner with a parting line which, for example, coincides with the drawing plane of FIG. 1. This allows lower section 5a of housing 5 to be opened along the parting line and to be closed again after container 9 has been positioned.

(11) First seal 6 and second seal 7 seal pressure chamber 2 in the various operating positions of sealer 3 and product feeder 4 in a gas-tight and liquid-tight manner in relation to the positive pressures and/or negative pressures prevailing during the working operation of filling-sealing unit 1 in vacuum chamber 2.

(12) First seal 6 there allows for a lifting motion 3a of sealer 3 substantially coaxial to center axis 9b of container 9 to a sealing position, in order to tightly seal neck finish 9c of container 9 with a closure 10, for example, a crown cap.

(13) Furthermore, second seal 7 allows for a linear motion 4a of product feeder 4 to a filling position in order to place an outlet opening 4b of product feeder 4 onto neck finish portion 9a of container 9 preferably in a self-centering manner around neck finish 9c. For gas-tight and liquid-tight placement of outlet opening 4b, for example, a fourth seal 4c can be formed therearound.

(14) It is only schematically indicated in FIG. 1 that product feeder 4 could also be placed onto neck finish portion 9a in an alternative linear motion 4a′ inclined relative to the lifting direction 3a of sealer 3. In this case as well, outlet opening 4b would be to be aligned orthogonally to center axis 9b.

(15) As a further alternative, a pivoting mechanism for product feeder 4 would also be conceivable to place the latter onto neck finish portion 9a, provided that a seal is given by way of second seal 7 against housing 5 and subsequent lowering of sealer 3 onto neck finish portion 9a.

(16) Indicated schematically in FIG. 1 are furthermore a first pressure line 11 for introducing a pressurization gas, in particular CO.sub.2, with a positive pressure into pressure chamber 2 and a second pressure line 12 for generating a negative pressure in pressure chamber 2. First pressure line 11 can also be referred to as a pressurization gas line, second pressure line 12 can also be referred to as a vacuum line.

(17) A cleaning agent for cleaning filling-sealing unit 1 overall (CIP) can be introduced via different product, pressurization gas and/or vacuum lines in a known manner, i.e. without disassembling or dismantling filling-sealing unit 1.

(18) The position of pressure lines 11, 12 in pressure chamber 2 is irrelevant, provided that the following described generation of positive pressure and/or negative pressure in pressure chamber 2 and/or the action of a cleaning agent are given. In principle, the positive pressure and/or negative pressure in pressure chamber 2 can also be generated by product feeder 4 and media lines connected thereto, see, for example, FIG. 2.

(19) FIG. 2 illustrates components of filling-sealing unit 1 in connection with a media lead known per se through product feeder 4 and in connection with an attachment 14 for covering third seal 8 against the exterior in a gas-tight manner.

(20) Attachment 14 can be temporarily attached to lower partial section 5a of housing 5 around sealing seat 5b formed therein in a sealing manner.

(21) For example, attachment 14 is a CIP cover for seal seat 5b and third seal 8. Attachment 14 can be attached in a gas-tight and liquid-tight manner, for example, for a CIP process, so that the region of sealing seat 5b is sealed independently of the function and structural integrity of third seal 8. For this purpose, for example, a fifth seal 14a is present at attachment 14.

(22) Product feeder 4 can be selectively connected to a product line 15, to a pressurization gas line 16 and to a vacuum line 17 by way of separately controllable valves 15a, 16a, 17a.

(23) Also schematically indicated are valves 11a, 12a for controlled and selective opening and closing of first and second pressure lines 11, 12.

(24) For example, a control unit 18 is available for time-coordinated actuation of valves 11a, 12a and 15a to 17a and can also be used for recording readings from a schematically indicated pressure sensor 19 for monitoring pressure profiles DV (see FIG. 5) in pressure chamber 2.

(25) First and second seals 6, 7 seal the regions of sealer 3 and the product feeder 4 independently of their positions in a liquid-tight and gas-tight manner at the pressures occurring during normal operation of filling-sealing unit 1. The same applies to third seal 8 with container 9 inserted.

(26) The invention is based on the idea to temporarily replace the function of third seal 8 and inserted container 9 with sealing attachment 14 and to at least in this configuration measure a pressure profile DV in pressure chamber 2 outside the production operation after a predetermined positive pressure ÜD and/or negative pressure UD has been generated (see FIG. 5).

(27) This is possible particularly efficiently, for example, in the context of overall cleaning (CIP). Such pressure profiles DV measured can then be compared to pressure values and/or pressure profiles DV measured during normal production operation and/or during additional tightness controls with containers 9 and/or suitable test members (not shown). Any leaks possibly detected can then respectively be assigned to first and second seals 6, 7 or to third seal 8.

(28) For this purpose, preferably all filling-sealing units 1 present at a filling-sealing machine 20 of the rotary type indicated schematically in FIG. 3 are connected to a CIP cleaning circuit 21. The inflow of the cleaning agent is there effected, for example, via a suitable product, pressurization gas and/or vacuum line and the outflow through attachment 14 (not shown), or otherwise. CIP cleaning is performed with a rotating filling-sealing machine 20 preferably simultaneously at all filling-sealing units 1.

(29) Individual tightness controls 30, 40, 50, 60 at filling-sealing units 1 are described below with reference to the flow charts of FIG. 4.

(30) According thereto, tightness control 30 with attachment 14 under the application of a positive pressure ÜD to pressure chamber 2 is performed as follows.

(31) In a step 31, attachment 14 is attached, for example, in the context of overall cleaning filling-sealing unit 1 (CIP), to lower section 5a of housing 5 around sealing seat 5b and pressure chamber 2 is there during tightness control 30 sealed in a gastight manner against the environment.

(32) In a subsequent step 32, first pressure line 11 is opened, for example, by opening valve 11a, and a pressurization gas is supplied into pressure chamber 2. The latter is preferably acted upon by at least the pressurization gas pressure used during the normal working operation of the filling-sealing unit, for example, with a positive pressure ÜD of at least 1 bar, in particular of at least 3 bar. Preferably CO.sub.2 is used as the pressurization gas which typically also serves as the pressurization gas during regular working operation. This allows tightness control of first and second seals 6, 7 under conditions of actual practice. However, the use of compressed air or the like would also be conceivable.

(33) In a subsequent step 33, the supply of the pressurization gas is interrupted by closing first pressure line 11, for example, by way of valve 11a. With correct operation of first and second seals 6, 7, the positive pressure ÜD generated in pressure chamber 2 should thereafter remain substantially constant for an appropriate monitoring period of, for example, 1 to 10 s.

(34) In a subsequent step 34, pressure profile DV in pressure chamber 2 is monitored, for example, with the aid of pressure sensor 19 and control unit 18 or a similar computing unit, over a predetermined period of time ZD (see FIG. 5) of for example 1 to 10 s. Pressure values measured by pressure sensor 19 are stored for further evaluation.

(35) In a subsequent step 35, pressure chamber 2 is depressurized in an appropriate manner, for example, by temporarily opening a negative pressure valve 12a, 16a.

(36) In a subsequent step 36, pressure profile DV measured in step 34 is verified for correctness. If an inadmissible pressure drop is detected, the cause of this can possibly already be assigned to first seal 6 and/or second seal 7 depending on the extent of the pressure drop, since the function of third seal 8 has previously been replaced by attachment 14. Although a malfunction of third seal 8 cannot yet be ruled out based on this alone, corrective maintenance or further tightness controls 40, 50 could still be initiated in a selective manner.

(37) In addition or alternatively, tightness control, in principle performed in an analog way with attachment 14, while pressure chamber 2 is acted upon with a negative pressure UD, is performed as follows.

(38) For this purpose, attachment 14 is attached in a step 41 analogous to step 31 or remains in its sealing position after tightness control 30.

(39) In a subsequent step 42, pressure chamber 2 is connected, for example, by opening valve 12a, to second pressure line 12 and thereby evacuated up to a negative pressure UD of, for example, 0.5 to 0.05 bar.

(40) In a subsequent step 43, second pressure line 12 is closed, for example, by closing valve 12a. If first seal 6 and second seal 7 function properly, the negative pressure UD generated in pressure chamber 2 in this way should remain substantially constant for an appropriate monitoring period of, for example, 1 to 10 s.

(41) In a subsequent step 44, the pressure profile DV in pressure chamber 2 is monitored starting out from the negative pressure UD generated in step 43 over a predetermined period of time ZD of, for example, 1 to 10 s. The pressure profile DV is measured, for example, with pressure sensor 19 and associated pressure values are transmitted to control unit 18 or a similar computing unit and stored there.

(42) In a subsequent step 45, pressure chamber 2 can be brought back to ambient pressure in an appropriate manner, for example by temporarily opening a positive pressure valve 11a, 15a.

(43) In a subsequent step 46, pressure profile DV measured in step 44 is verified for correctness. If an inadmissible pressure increase is detected, the cause of this can possibly already be assigned to first seal 6 and/or second seal 7 depending on the extent of the pressure increase, since the function of third seal 8 has previously been replaced by attachment 14. Although a malfunction of third seal 8 cannot yet be ruled out based on this alone, corrective maintenance measures or further tightness controls 30, 50 can possibly be initiated in a selective manner.

(44) Tightness controls 30, 40 with attachments 14 are preferably performed at each of filling-sealing units 20 present at filling-sealing machine 1. This is possible in parallel at all filling-sealing units 1. The pressure values measured with respective pressure sensors 19 can be read out in a known manner and transmitted to control unit 18 or a similar computing unit for evaluation.

(45) Tightness control 50 of each filling-sealing unit 1 is preferably performed in a basically analogous manner without attachment 14 and instead with a container disposed in third seal 8 while pressure chamber 2 is acted upon with a positive pressure ÜD as follows.

(46) In a step 51, each filling-sealing unit 1 is fed a container 9 and its neck finish portion 9a is received by third seal 8 and thus tightly enclosed, for example, by compressed air acting thereupon.

(47) Steps 32 to 35 are subsequently performed.

(48) In a subsequent step 56, pressure profile DV measured in preceding step 34 is verified for correctness. If an inadmissible pressure drop is detected, the cause can possibly already be assigned to third seal 8, in particular with correct pressure profile DV of comparable tightness control 30 depending on the extent of the pressure drop. A malfunction of third seal 8 can be reliably detected or excluded in comparison with tightness control 30 which was also performed with attachment 14. As a result, corrective maintenance can possibly be initiated in a selective manner and performed quickly.

(49) Tightness control 60 of each filling-sealing unit 1 is preferably additionally performed in a basically analogous manner without attachment 14 and with a container disposed in third seal 8 while pressure chamber 2 is acted upon with an underpressure UD as follows.

(50) In a step 61, each filling-sealing unit 1 is fed a container 9 and its neck finish portion 9a is received by third seal 8 and thus tightly enclosed, for example, by compressed air acting thereupon.

(51) Steps 42 to 45 are subsequently performed.

(52) In a subsequent step 66, pressure profile DV measured in preceding step 44 is verified for correctness. If an inadmissible pressure increase is detected, the cause can possibly already be assigned to third seal 8, in particular with correct pressure profile DV of comparable tightness control 40 and depending on the extent of the pressure increase. A malfunction of third seal 8 can be reliably detected or excluded in comparison with tightness control 40 which was also performed with attachment 14. As a result, corrective maintenance can possibly be initiated in a selective manner and performed quickly.

(53) Steps 32 to 34 and 42 to 44 can be basically performed with containers 9 with product feeder 4 attached or not attached, i.e. including or excluding the container volume.

(54) Steps 32 to 34 and 42 to 44 could also be performed with the aid of pressurization gas line 15 and valve 15a or with vacuum line 16 and valve 16a.

(55) Tightness controls 50, 60 with containers 9 attached can be performed in the form of test runs of filling-sealing machine 20 with a rotational speed DZ that is reduced compared to normal operation (see FIG. 3) in order to extend the monitoring of the pressure profile DV in an appropriate manner. Similarly, tightness controls 50, 60 are possible particularly in step with practice at the rotational speed DZ used during production operations.

(56) The test runs preferably each comprise at least two revolutions of all filling-sealing units 1, so that their tightness controls 50, 60 are each performed with at least two different containers 9. This takes account of faults due to manufacturing tolerances of containers 9.

(57) Separate test runs for tightness control 50, 60 of filling-sealing units 1 with containers 9 can be optimized in a selective manner to meet the requirements for good readings of pressure profiles DV generated in pressure chamber 2.

(58) It is also conceivable to integrate tightness controls 50, 60 into a normal filling-sealing process of the production operation with containers 9 inserted. For example, the pressurization gas, in particular CO.sub.2, can be filled up to a predetermined positive pressure ÜD into containers 9 and into pressure chamber 2 for expelling oxygen from containers 9 prior to the filling process. Monitoring pressure profile DV in pressure chamber 2 is possible at least over a comparatively short period of time ZD.

(59) The tightness controls 30, 40 with attachments 14 can be performed at suitable control intervals, cleaning intervals or, in case of suspicion of leakage, based on the pressure profiles measured during regular production operation.

(60) Third seal 3 is comparatively sensitive due to its split design and the stress when receiving and sealing containers 9. Separate tightness control 30, 40 of first and second seals 6, 7 with attachment 14 facilitates the quick assignment of leaks and a timely replacement of the seal.

(61) If one of the checked filling-sealing units 1 does not meet the requirements for the pressure profiles DV at positive pressure ÜD and/or negative pressure DU with attachment 14 and/or with container 9 inserted, then respective filling-sealing unit 1 is preferably moved to a suitable maintenance point 22 of filling-sealing machine 20. There, the respective filling-sealing unit 1 can be repaired, for example, by replacing improperly working seals 6, 7, 8. Preferably, all filling-sealing units 1, which are recognized as not being improperly sealed, are moved successively to maintenance point 22 for the respective repair.

(62) Tightness controls 50, 60 with containers 9 inserted can regularly be integrated into the ongoing production operation at predetermined control intervals. If existing or imminent leaks are detected at individual filling-sealing units 1, tightness controls 30, 40 can be performed with attachment 14 with little effort in equipment and time, for example, in the context of overall cleaning (CIP).

(63) The results of all tightness controls 30, 40, 50, 60 can be incorporated into trend analyses in order to monitor the function of seals 6, 7, 8 in the long term and, for example, to prevent an imminent malfunction of the filling-sealing units 1 by corrective maintenance. For example, pressure profiles DV of individual filling-sealing units 1, each from similar tightness controls 30, 40, 50, 60, can be compared to each other. An increase in the recorded pressure drops or pressure increases then indicates a deteriorating function of the first and second seals 6, 7 or third seal 8.

(64) As an alternative to containers 9, test members (not shown) could be used to eliminate or simulate certain manufacturing tolerances of containers 9 for tightness control 50, 60. Tightness control 50, 60 itself can then be verified and possibly be optimized in terms of its information content and reliability.

(65) FIG. 5 schematically illustrates step 34, namely monitoring pressure profile DV in pressure chamber 2 over a period of time ZD after a positive pressure ÜD has been generated. Schematically indicated are furthermore above described steps 32, 33 and 35. For better understanding, negative pressure DU is further indicated, the course of which would be monitored in step 44 (not shown in FIG. 5) in a respective manner.