EP1004510B1 - Method and apparatus for sterilising and cleaning webs of packaging material for manufacturing packages - Google Patents

Description

The invention relates to a method and an apparatus for Germ reduction and cleaning of at least the product side Area of a packaging material web passing through a sterile flow chamber made of plastic using water vapor as Sterilant.

The use of steam for sterilization purposes is generally known, for example according to DE-A-195 07 639 A1, DE-A-196 26 705 A1 and DE-A-30 16 266 A1. These processes work with saturated steam. In the first two methods mentioned, the packaging material web is sprayed with steam and in the method according to DE-A-30 16 266, the saturated steam is sprayed on with the flow or sterilization chamber closed in time.
Since 1985, however, according to US-A-4,537,007 corresponding to the preambles of claims 1, 6, 11 and 15, working with superheated steam was also considered, which is jetted onto a packaging material web passing through a sterilization chamber, although the packaging material web had previously been relatively hot water bath, held just below the boiling limit, which simultaneously hermetically seals the lower inlet opening of the sterilization chamber.
As far as is known, this process has apparently not been put into practice. The reasons for this are likely to be found in the fact that the packaging material webs, which are usually made of suitable plastic for packaging purposes, are difficult to uniformly wet with water and that this process does not produce a coherent condensate film on the packaging material web, which in the hot state is an essential prerequisite for a satisfactory Germ killing is. Since the packaging material web in the process according to US-A-4,537,007, also heated by the hot water bath itself, if at all only drops into the flow chamber when wetted dropwise, the superheated steam, which apparently should also serve in particular to dry the packaging material web, should only be used unevenly Effect come because it hits wetted and unwetted packaging material areas. In addition, the steam is supplied to the flow-through or sterile chamber already in the overheated state, which requires an overheating unit outside the flow-through chamber and correspondingly insulated steam feed lines, whereby it must also be taken into account that only saturated steam networks are generally available in the installation rooms of packaging machines.

Based on this prior art, the invention lies The task is based on a method and a device for its To create implementation with which the steam is rational first where it is converted into superheated steam where it is actually needed and as superheated steam on the dry entering Packaging material web in order to form a uniform, thin Condensate film is sprayed.

This task is related to a first method according to the Invention by the characterizing part of the independent claim 1 listed features solved.

This solution can, as will be explained in more detail, both with relative movement of the packaging material web to the nozzle as well realize standing packaging material web. Regarding more advantageous and preferred embodiments of the method is based on the dependent claims 2 to 5 referenced. Regarding the device to carry out this procedure on the independent Claim 11.

A second method, in particular with clocked packaging material conveyor works, results from the characteristics in Characteristics of independent claim 6 and the associated Device for its implementation according to the independent Claim 15.

Which in both cases involves the conversion of the supplied Saturated steam in superheated steam affects it immediately in front of the nozzle opening or in the nozzle.

With the two methods according to the invention and the associated devices, the demands made are met because, on the one hand, a smaller amount of saturated steam has to be generated or supplied and, on the other hand, due to its conversion into superheated steam, a smaller but nevertheless necessary amount of condensate is obtained before the spraying and this condensate precipitating in a thin layer on the packaging material web is used specifically for thermal germ killing as a result of the temperature gradient between the superheated steam temperature and the packaging material web temperature level. On the detour of converting saturated steam into superheated steam, the "middle way" between too much and too little condensate is chosen according to the invention, which ensures that condensate necessary for germ killing is largely present evenly in a thin layer, but not the other Heat transfer to the packaging material web hinders, as can be the case with too much and then laughing condensate.
The principle of germ reduction by moist heat which is known per se is therefore also maintained with the steam superheating which is advantageous for the reduced condensate formation. Regarding the characteristics "sterile flow chamber" and "with essentially the same intensity ..." with regard to the gating, the following should be pointed out:

The sterile flow chamber is a simple, box-shaped housing with slot-shaped inlet and outlet openings for the packaging material web, this housing with respect to Evaporation cavities according to the aforementioned two first publications has a volume that is many times larger. There the steam from a short distance (nozzle opening distance to the packaging material web about 5-6 mm in the first procedure) immediately the packaging material web is sprayed on, has the sterile flow chamber no directing or guiding function for the superheated steam in with respect to the packaging material web, which is also not necessary, since how said, the more or less overheated steam immediately the packaging material web is sprayed on.

As for the other requirement "with the same intensity", so this ultimately relates to the design of the nozzle, and taking into account the width of the packaging material, as is known depending on the further processing route or connected Width of the processing machine for the packaging material web accordingly for example in the order of 200 to 800 mm can vary. So it must be in relation to the present ones Nozzle must be taken care that the nozzle intensity also wider packaging material strips evenly over their entire width is guaranteed. So under "at least one nozzle" is too understand that not only two nozzles in the direction of flow can be provided in series, but that several, depending on the width of the packaging material to be treated can be arranged side by side, which in their effective range for the corresponding beam intensity to care. Under "nozzle" there is also one closer to illustrative embodiment according to independent claim 15 to understand in the form of a so-called vaporization box, the is intended for carrying out the second method.

The controllability of the energy supply to the Nozzle to indicate the degree of overheating of the saturated steam and thus also influence the accumulation of condensate on the packaging material web to be able to take the one for optimal germ reduction or

Further processing of packaging material web should be as large as necessary but as low as possible.
This controllability also takes place expediently with regard to the temperature of the incoming packaging material web, ie, the previous need, as a rule, to bring a new packaging material web roll to the temperature in the installation space of the packaging machine is eliminated. If the incoming packaging material web still has an undertemperature measured by a temperature sensor, the amount of steam to be applied is reduced accordingly, since condensate is increasingly deposited on a colder surface or packaging material web.
Of course, the saturated steam supply to the device or to the nozzle can also be controlled or switched on and off in a known manner, on the one hand directly in relation to the nozzle jet intensity and on the other hand also with regard to the fact that the packaging material web is cycled to the rhythm of the following processing machine is conveyed through the sterile flow chamber, which is to be preferred insofar as the mechanical outlay is thereby reduced, since there is no need for a complex mechanical transition area (accumulation loop guide) for a packaging material web that continuously enters the sterile flow chamber and is then clocked into the subsequent processing machine. However, this is associated with a greater control effort, because then the steam supply must be switched on and off per conveying cycle in such a way that the condition of steam injection during the transport of the packaging material web is fulfilled. Bezgl. of this packaging material web transport or the movement of the packaging material web during the gating, it should be pointed out that this movement condition can also be fulfilled in that when the packaging material web is at a standstill either the entire pass-through chamber with its elements located therein or only the slot die in the then stationary one through chamber. Advantageous further developments that result in this context are explained in more detail.

Fig.1

die erfindungsgemäße Vorrichtung in Verbindung mit einer nachgeschalteten Weiterverarbeitungsstrecke für einen insgesamt getakteten Durchlauf der Packstoffbahn;

Fig.2

eine der Fig. 1 entsprechende Darstellung für eine kontinuierliche Packstoffbahnzufuhr zur erfindungsgemäßen Vorrichtung und nachfolgend getakteter Weiterführung in die Weiterbehandlungsstrecke;

Fig.3

die erfindungsgemäße Vorrichtung in Verbindung mit einer nachgeschalteten Verpackungsmaschine zur Herstellung von Schlauchbeuteln;

Fig.4

in bezug auf Fig. 1 vergrößert die erfindungsgemäße Vorrichtung zur Durchführung des Verfahrens;

Fig.5

stark schematisiert einen Schnitt durch eine Düse;

Fig.6

schematisch eine besondere Ausführungsform der Vorrichtung;

Fig.7

in Form eines Diagramms die Bewegungsabläufe der Durchlaufkammer und der Packstoffbahn bei getaktet bewegter Durchlaufkammer;

Fig.8

perspektivisch und schematisch die bevorzugte Ausfühform der Vorrichtung und

Fig.9

schematisch einen Längsschnitt durch die Düse nach Fig.7

The two methods according to the invention, which differ only slightly per se, the devices for carrying them out and advantageous further developments are explained in more detail below with reference to the drawing of exemplary embodiments.
It shows schematically

Fig.1

the device according to the invention in connection with a downstream processing section for an overall clocked passage of the packaging material web;

Fig.2

1 a representation corresponding to FIG. 1 for a continuous supply of packaging material to the device according to the invention and subsequently cycled continuation into the further processing section;

Figure 3

the device according to the invention in connection with a downstream packaging machine for the production of tubular bags;

Figure 4

1, the device according to the invention for carrying out the method is enlarged;

Figure 5

highly schematic a section through a nozzle;

Figure 6

schematically a particular embodiment of the device;

Figure 7

in the form of a diagram, the movement sequences of the flow chamber and the packaging material web with the movement of the flow chamber;

Figure 8

perspective and schematic of the preferred embodiment of the device and

Figure 9

schematically shows a longitudinal section through the nozzle of Figure 7

The device for carrying out the first method consists of a packaging material roll holder 1 with a downstream sterilization flow chamber 2 and means for controllable steam supply, behind which flow chamber 2 a sterile further processing section 3 is arranged, which is formed by a packaging machine. This flow chamber 2 is provided with inlet and outlet slots 2 ′, 2 ″ for the packaging material web PB. The exemplary embodiments shown in FIGS. 1, 2 are a deep-drawing machine as a further processing section 3, with which on the packaging material web PB running through in time For example, cups in subsequent stations F, F, S are formed, filled, closed and then the cups are separated from the packaging material strand individually or in groups in a punching station ST For a cover film web DB to be fed to the closing station S, which of course also has to be sterilized, is over the closing station S a corresponding flow chamber 2 is arranged, which is only indicated by dashed lines at the top right in Fig.1
In the exemplary embodiment according to FIG. 1, the packaging material web PB is conveyed through the pass-through chamber 2 in a clocked manner, while according to FIG. 2 the continuous inflow behind the pass-through chamber 2 is converted into a clocked further conveyance, for which purpose a packing material web stowage loop receiving space 20 is required.
All of the means FM required for such promotions and web guides are shown only schematically and in dashed lines in FIG. 1 and also do not require any special explanation, since they are well known, especially since in the end only the upstream section 3, however this may be designed, is connected upstream Device for hot steam treatment of the undeformed packaging material web PB is of interest. For the sake of completeness, the device for sterilizing in connection with a packaging machine SM for the production of tubular bags is illustrated in FIG. 3.
For the device for carrying out the first method, with reference to FIG. 4, it is essential that the steam supply in the form of at least one substantially transversely to the direction of the packaging material passage, in the sterile flow chamber 2 provided with a condensate discharge 14 and open towards the atmosphere with a small outlet distance D is formed above the packaging material web passage plane E, its internal steam duct 4 leading to the nozzle opening 7 is provided with an adjustable and opposed. sensor-controlled energy supply device 6 (for example, electrical heating resistor) is provided. For the sensory detection of the temperature of the incoming packaging material web, a temperature sensor 29 is arranged in front of the sterile flow chamber 2, with which influence is exerted on the energy supply and thus on the degree of overheating of the steam to be injected.
In FIG. 4 the control for the energy supply device 6 is also designated with 21, the steam pressure and steam quantity control with 22 and the saturated steam supply line with 23. In addition, the flow chamber 2 is provided with a condensate drain 14, specifically for condensate which precipitates on the walls of the flow chamber.
With this device, the saturated steam supplied through the line 23 and from the valve 22 is converted into superheated steam directly in the nozzle itself before being applied to the packaging material web PB by a correspondingly regulated supply of energy and then onto the packaging material web PB conveyed through the open-air chamber 2 during the transport movement of which is sprayed transversely to this on at least the product side from a short distance D with essentially the same intensity over the width of the packaging material B, which, as has been shown, leads to an extremely effective germ reduction.
The saturated steam supplied, for example, at 5.5 bar emerges at a nozzle 5 kept at approximately 300 ° C. by supplying energy via device 6 at approximately 200 ° C. The nozzle 5 is designed so that the steam jet sprayed out has essentially the same intensity over the entire width of the packaging material B. With a large width of the packaging material web PB, this means that within a nozzle head 5 '(see FIG. 5) there are several chambers 24 which can be fed evenly with steam and which have slot openings 25 with a maximum width of 10 to 20 mm. Depending on the width of the packaging material web, a plurality of such nozzle designs are arranged side by side in a nozzle head 5 ', only three of which are shown in FIG.
1 clocked through the flow chamber 2, the saturated steam supply is effected in a clocked manner via a correspondingly also controlled on-off controller, which can be integrated in the controller 22, i.e. the spraying takes place only when the Packing material web PB moves with its affected section in the through-flow chamber 2, whereby, if the required disinfection rate requires it, it is entirely possible to arrange two nozzles 5 or nozzle heads 5 'one behind the other, as indicated by dashed lines in FIG. 4.
If the packaging material web PB is to continuously run through the flow chamber 2, which makes it unnecessary to switch the steam supply on and ultimately ensures more uniform vapor deposition conditions, then the sterile flow chamber 2 has the first part of the downstream, sterile further processing section 3 in the form of a packaging material web which is also to be kept sterile Exchange barrel-receiving space 20 is formed, and behind this means FM are arranged for the timed withdrawal of the sterile packaging material web PB, which means are only indicated schematically, especially since these are the clock conveying means of the downstream packaging machine.

As can further be seen from FIG. 4, a so-called condensate doctor blade 26 is also arranged in the through-flow chamber 2 behind the at least one nozzle 5, essentially transversely to the through-flow direction, from which the scraped-off condensate KO, for example, by means of an air-operated suction device that operates on the principle of a Venturi nozzle 27 is discharged. In contrast to the vacuum pumps otherwise used, this suction device 27 has the advantage that it is completely insensitive to the kill media and their residues. Since, when the device is in operation, the steam is freely sprayed into the flow chamber 2 on the packaging material PB and the relaxing steam also spreads throughout the flow chamber and also precipitates on the walls thereof, as mentioned above, it is provided with a condensate drain 14, which leads to a Condensate drain 14 'provided collector 28, which also receives the condensate KO coming from the condensate doctor 26. The condensate drain 14 is also connected to a suction device 27, in which a strong air flow is supplied to the condensate flow, so that suction is generated at the condensate drain 14 (Venturi nozzle principle).
With regard to the steam distribution in the flow chamber 2, a condensate suction device 26 'is also expediently arranged on the underside of the packaging material web PB.
The same also applies to the nozzle 5, which, if this requires the further treatment section 3 to be kept sterile, i.e. where the underside of the packaging material web is also passed through a so-called full tunnel 30 in a sterile manner (see FIG. 1), so that at least one is also in the through-flow chamber 2 from below arranged nozzle directed against the packaging material.
As far as the requirement for the nozzle arrangement "with a short distance D to the packaging material web" is concerned, it has a size of 4 to 8 mm. Advantageously, the nozzle 5 is arranged in the pass-through chamber 2 with respect to its distance and inclination (see arrows on the second nozzle shown in dashed lines) so that optimal distance and inclination settings can be made for the respectively treated packaging material web. The inclination of the nozzle shown in FIG. 4 in the direction of passage has proven to be particularly advantageous since the condensate film which forms under the nozzle on the web runs away from the nozzle with the packaging material web.

In the exemplary embodiments described so far, either steamed continuously or clocked. With the continuous Vaporization is as mentioned above and in Fig. 2, a packing material storage loop receiving space 20 is required, for a perfect packaging material web transport the transition point between continuous steaming and To be able to guarantee timed further treatment. To avoid of such a packing material storage loop receiving space 20 is, as shown in Figure 6, advantageously provided that Pass-through chamber 2 in and against the running direction of the packaging material web PB slidable to store, the displacement path corresponds at least to the material feed rate per cycle. to Clarification of the functioning of the movable stored Sterile flow chamber 2 (slide drive not shown) 7 are the movements of the packaging material feed (dashed lines) and the feed of the Flow chamber 2 (solid lines) to each other in one Chart plotted. It is essential that the vaporization of the Packaging material web in the same period as, for example, the deep drawing of the already sterilized packaging material web and that the time span for the packaging material feed for the return movement of the Flow chamber 2 is used. To make a sterile transition from the flow chamber 2 to the further processing section 3 to ensure, as shown schematically in Fig. 6, advantageously a sealed between these two chambers Telescopic housing 31 or a bellows arranged.

In accordance with the second sterilization process, which basically differs only insignificantly from the one described above, the procedure is such that saturated steam is fed to the nozzle and the saturated steam is heated before application to the packaging material web by controlled supply of energy immediately before it is sprayed out, and the superheated steam is injected into one over treating steam packaging section formed is sprayed over the entire surface in the steam storage space kept closed during the vapor deposition onto the packaging material PB with formation of a condensate film.
For this purpose, the nozzle 5 according to FIGS. 8, 9 is designed in the form of a heatable steaming box 8 with an inner steam distribution chamber 9, which is closed off from the packaging material pass plane E with a nozzle plate 10 containing a plurality of nozzle openings 7 '. The nozzle plate 10 is advantageously formed from a central part 10 'and from two edge parts 10 ", the separately held distribution and distribution chambers 11 of which are connected to separate, controllable saturated steam supply lines 4". On the packaging material web side, the steaming box 8 is provided with a seal 13 delimiting a steam storage space 12.
Depending on the design of this seal 13, the device designed in this way can be operated both in a clocked manner and with a continuously running packaging material web PB.
When the seal 13 according to FIG. 9 is formed, for example in the form of an O-ring seal following the circumferential contour of the box, the stopped packaging material web section is pressed against the seal 13 from below with a plate 8 ″ shown only in broken lines in FIG that a self-contained steam storage space 12 is available for the full-surface spraying with superheated steam, after its completion the plate 8 "is again slightly lowered and the residual steam (saturated steam / wet steam) can escape into the continuous flow chamber 2.
However, the seal 13 can also be designed in the form of a circumferential, more or less flexible lip seal (not particularly shown), which then also delimits a vapor storage space 12, but which remains open all around due to a narrow gap between the seal 13 and the packaging material web PB. With continuous steaming with superheated steam, the packaging material web can also be conveyed continuously under the steaming box 8, which then, depending on the operating mode of the downstream packaging machine. and as mentioned above, a damming loop guide 20 according to FIG. 2 of the packaging material PB requires.
The formation of such a steam storage space 12, which can also be provided for the nozzles 5 according to FIG. 4 (indicated by dots there), has proven to be advantageous in that, as has been shown, the edge areas of a continuous packaging material web are also suitable for this let the optimized disinfection be recorded with certainty.
In this embodiment, as can be seen from FIG. 9, the vaporization box 8 forming the “nozzle” is provided with a controllable, electrical heating resistor 8 ′, which includes the entire upper part of the box 8, which also contains the saturated steam distribution lines 4, for converting the saturated steam into superheated steam Temperature.

Claims (20)

1. A process for germ reduction and cleansing at least the loading-material-sided surface of a sheet of packing material (PB) passing through a sterilizing passage chamber (2) by means of overheated steam sprayed through at least one nozzle (5), with the sterilized sheet of packing material, subsequently, being guided into a sterile tunnel (3) of a packing machine and the sterilizing passage chamber (2) and the sterile tunnel, relative to the atmosphere, being held at a slight excess pressure,
   characterized in that saturated steam is supplied to the nozzle (5), with the saturated steam prior to being applied to the section of the sheet of packing material contained in the sterilizing passage chamber (2) and introduced in dry condition into the chamber (2), through controlled energy supply, is overheated immediately before being sprayed, and that the said overheated steam with a substantially uniform intensity across the entire length of at least one transverse line of the sheet of packing material is sprayed onto said sheet of packing material, forming a condensate film.
2. A process according to claim 1,
   characterized in that the condensate film formed on the surface of the sheet of packing material steamed in the passage chamber (2) is thereafter subjected to a condensate absorption before leaving the sterilizing passage chamber.
3. A process according to claims 1 or 2,
   characterized in that the hot steam is sprayed at an inclination relative to the sheet of packing material and in the passage direction thereof.
4. A process according to any one of claims 1 through 3,
   characterized in that the section of the sheet of packing material is held in movement relative to the sprayed hot steam.
5. A process according to any one of claims 1 through 4,
   characterized in that in a cyclical transport of the sheet of packing material through the sterilizing passage chamber (2), the steam is sprayed in a corresponding cyclical way.
6. A process for germ reduction and cleansing at least the loading-material-sided surface of a sheet of packing material (PB) passing through a sterilizing passage chamber (2) by means of overheated steam sprayed through at least one nozzle (5), with the sterilized sheet of packing material, subsequently, being introduced into a sterile tunnel (3) of a packing machine and the sterilizing passage chamber (2) and the sterile tunnel, relative to the atmosphere, being held at a slight excess pressure,
   characterized in that saturated steam is supplied to the nozzle (5)), with the saturated steam prior to being applied to the section of the sheet of packing material contained in the sterilizing passage chamber (2) and cyclically introduced, in dry condition, into the chamber (2), through controlled energy supply, is overheated immediately before being sprayed and the said overheated steam, within a steam-stowing space (12) formed above the section of the sheet of packing material to be treated, is sprayed with a substantially identical intensity, inside the steam-stowing space kept closed during steaming, across the entire surface of the sheet of packing material, forming a condensate film.
7. A process according to claim 6,
   characterized in that the condensate film formed on the surface of the sheet of packing material as steamed in the steam-stowing space (12), with the steam-stowing space opened, is thereafter subjected to a condensate absorption before leaving the sterilizing passage chamber (2).
8. A process according to claims 6 or 7,
   characterized in that spraying of the hot steam is effected with the steam-stowing space (12) held closed.
9. The process according to any one of claims 1 through 8,
   characterized in that the resultant excess steam contained in the sterilizing chamber (2) is absorbed therefrom.
10. A process according to any one of claims 1 through 9,
    characterized in that overheating of the saturated steam as supplied is controlled in response to the temperature of the sheet of packing material.
11. A device for carrying out the process according to claim 1, comprising a sheet reel holder (1) with a sterilizing chamber (2) disposed therebehind, including a means (4) for the controlled steam supply and including at least one nozzle (5), with a sterile tunnel (3) of a packing machine connected to the passage chamber (2) being provided behind the sterilizing passage chamber (2),
    characterized in that the sheet of packing material (PB) can be introduced into the chamber (2) in dry condition, that the means (4) for the steam supply comprises an adjustably designed saturated steam feeder (4) within the sterilizing passage chamber (2) leading to the at lest one nozzle (5) sweeping the width of the sheet of packing material, and that an adjustable energy supply means (6) is provided for raising the saturated steam temperature to hot steam temperature immediately prior to being sprayed, and that the nozzle (5), ahead of its port (7) is provided with elements (7) for the uniform distribution of hot steam.
12. A device according to claim 11,
    characterized in that arranged ahead of the outlet port (2') of chamber (2), within the said chamber, is a condensate film absorbing means (26).
13. A device according to claims 11 or 12,
    characterized in that the energy supply means (6) is provided on a steam guiding element (4') arranged immediately ahead of the nozzle port (7).
14. A device according to any one of claims 11 through 13,
    characterized in that the at least one nozzle (5) is designed to be adjustable in distance and/or inclination relative to the sheet passage plane (E).
15. A device for carrying out the process of claim 6, comprising a sheet reel holder (1) with a sterilizing passage chamber (2) provided therebehind, including a means (4) for the controlled steam supply and including at least one nozzle (5), with a sterile tunnel (3) of a packing machine connected to the passage chamber (2) being provided behind the sterilizing passage chamber (2),
    characterized in that the sheet of packing material (PB) can be introduced into the chamber (2) in dry condition, that the means (4) for the steam supply comprises an adjustably designed saturated steam feeder, and that inside the sterilizing passage chamber (2), the nozzle (5) is designed in the form of a heatable steaming box (8) cyclically mounted on the sheet of packing material, with an internal steam distributing chamber (9) sealed against the sheet passage plane (E) by a nozzle plate (10) containing a plurality of nozzle ports (7', forming a steam-stowing space (12), and that the steaming box (8) is provided with an adjustable energy supply means (6) for raising the saturated steam temperature to hot steam temperature, and that the nozzle (5), ahead of its port (7) is provided with elements for the uniform distribution of hot steam.
16. A device according to claim 15,
    characterized in that arranged before the outlet port (2') of chamber (2), within the said chamber (2), is a condensate absorbing means (26).
17. A device according to claims 15 or 16,
    characterized in that the nozzle plate (10) is formed of a central section (10') and two marginal sections (10") whose separately held distributing and allocating chambers (11) are connected to separate and adjustable saturated steam feeders (4").
18. A device according to any one of claims 11 through 17,
    characterized in that the steaming box (8), on the side of the sheet of packing material, is provided with a sealant (13) confining the steam-stowing space 12.
19. A device according to any one of claims 11 through 18,
    characterized in that the sterilizing passage chamber (2) is provided with a condensate discharge means (14).
20. A device according to any one of claims 11 through 19,
    characterized in that arranged ahead of the inlet of the sterilizing passage chamber (2) is a temperature sensor (30) for the sheet of packing material.

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