EP1351714A1

EP1351714A1 - System for continuous sterilization of bottles or other containers for pharmaceutical or similar use

Info

Publication number: EP1351714A1
Application number: EP01272238A
Authority: EP
Inventors: Carlo Stazzoni
Original assignee: Aautomag Srl
Current assignee: Aautomag Srl
Priority date: 2000-12-22
Filing date: 2001-12-17
Publication date: 2003-10-15
Also published as: ITFI20000259A1; IT1314894B1; WO2002051450A1

Abstract

The system comprises: a laminar-air-flow intake module for intake of the bottles, a hot-laminar-air-flow sterilization module, and a laminar-air-flow cooling module for cooling the bottles before they are unloaded. The bottles are displaced within the sterilization system by means of a conveyor-belt system which is provided with separate and consecutive conveyor-belts (109A, 109B, 109C), the belt (109A) that traverses the intake module being different and separate from the conveyor belt (109C) that traverses the cooling and unloading module.

Description

System for continuous sterilization of bottles or other containers for pharmaceutical or similar use

DESCRIPTION In current laminar-air-flow sterilization tunnels for sterilizing glass vials and bottles for pharmaceutical or similar uses, a single belt conveys the bottles to be sterilized through three areas in succession, one of which is equipped for performing a function of laminar-air-flow protection, another for performing a sterilization function with a laminar flow of hot air (typically, 300- 350°C), and yet another for performing a function of cooling down to a temperature that is suitable for the subsequent processing steps, typically the steps of filling the bottles with the product, closing the bottles and packaging them. The need has emerged to carry out periodical sterilization of the area where the cooling process takes place, in so far as this area could be the site of polluting agents that are dangerous both for the product and for the operators. Consequently, different techniques have been developed to provide said cooling area or the entire tunnel with equipment and devices designed for carrying out chemical or thermal sterilization thereof. However, even with these solutions, the cooling area may in any case receive, from the processing steps carried out downstream, in particular from the step of filling of the bottles, polluting agents which, during use of the system, may propagate back up to the intake area by way of the return branch of the conveyor belt that conveys the bottles. In the case of polluting agents that are biologically dangerous for man, this condition is particularly detrimental, given the possibility of uncontrolled access to the bottle-loading area by operators or maintenance staff.

The purpose of the present invention is to overcome the above drawback in systems designed for continuous sterilization of glass containers or similar containers for pharmaceutical use.

The sterilization system according to the invention is made up of three independent modules which are designed to perform the functions specified below: - a first laminar-air-flow intake module set in a position corresponding to the area where the bottles to be filled are loaded. A laminar flow of air filtered for elimination of dust is generated, which impinges from above upon the open and empty bottles that are resting on a conveyor belt which traverses the said first module; - a second hot-laminar-air-flow sterilization module, in which the bottles, which are resting on a conveyor belt that traverses said second module, are impinged upon by a laminar flow of air filtered and heated (typically, up to 300-350°C) for sterilization; - a third filtered-laminar-air-flow cooling module, in which the sterilized bottles, which rest on a conveyor belt that traverses said third module, are impinged upon by a laminar flow of air filtered at room temperature, in such a way that they are cooled before the product is introduced into them, and at the same time entry of dust into the bottles is prevented.

According to the invention, the system of said conveyor belts is made up of at least two separate and consecutive belts in such a way that each belt upstream will discharge the bottles, by means of tangential connecting surfaces, onto the next belt, the belt that traverses the intake module being different and separate from the conveyor belt that traverses the cooling module. With the above configuration there is eliminated the continuity of a possible return path at a low temperature from the output to the intake of the sterilization system via the return branch of the belt, and consequently there no longer exists any risk of dangerous polluting agents coming into contact with the operators. In addition, in a preferred constructional solution, the return branch of the belt of each module is made to: pass inside the module itself. In this way, the return branch of the sterilization module is kept at a high temperature, with a consequent sterilizing effect also on possible contaminating particles coming from the processing steps downstream of the sterilization system.

The aforesaid configuration moreover affords the following advantages: - the belts and the systems dedicated thereto for handling- ^"and moving are much lighter as a result of the fact that they have to move only one part of the weight of containers as compared to continuous belts of the tunnels according to the prior art; the aforesaid advantage enables the construction of compact mechanical drives, which are suited for being positioned in the top part of the machine;

- beneath the belt of each module larger spaces are available to the advantage of the circulation of the respective laminar flows described previously;

- in the sterilization module it is possible to mount heating resistors underneath the belt, thus reducing the overall height of the module; said resistors are easier to access, and maintenance thereof is facilitated; - since the resistors are positioned underneath the bottom return branch of the belt, they have a heating effect on the latter by irradiation; in this way, instead of being heated only indirectly by convection by the laminar flow of hot air, the belt is also heated directly by irradiation by the resistors, and the overall sterilization efficiency of the module is thus improved as compared to known solutions;

- in the cooling module, the entire section of the module in plan view is available for housing the air-cooling exchanger, which is an element that is always subjected to exacting conditions in known applications as a result of the small amount of space available; - the adoption of separate belts moreover enables complete closing between one module and the next, in view of the fact that the belt is not a through belt; this makes it possible to apply specific treatment processes separately for each module, limiting the impact of said processes to the module concerned alone; - the conformation according to the invention facilitates a modular configuration of the structure of the system. In particular, said modular structure can be configured according to another patent application in the name of the present applicant, which bears the same date as the present application and relates to a modular structure. In this case, the modular sterilization system may be designed with different widths of the conveyor belts in the various modules, in order to obtain, for instance, given one and the same length for each module, sterilization systems having greater cooling potential by mounting a wider cooling module, or else in order to make it possible to vary subsequently the cooling or sterilizing capacity by replacing the modules with others having different widths; and

- the adoption of a modular structure according to the above-mentioned other patent application bearing the same date as the present application also makes it possible, in the future, to replace individual parts of the system with modules that have innovative characteristics with respect to the previous ones, without having to replace the entire machine.

Preferably provided in a sterilization system according to the invention are systems for closing the connection openings between one module and the next, as well as for closing the loading and unloading openings of the sterilization system. In particular, the following are envisaged:

- a closing system with gates that act from above and the position of which is automatically adjusted according to the presence of items on the belt during production; and

-. a closing system that acts from beneath and is designed for hermetic closing between one module and the adjacent one during the conditioning operations with sterilizing agents for sterilizing the modules.

The variations in width in plan view referred to above enable an increase in the cooling capacity alone, or else an increase both in the cooling capacity and in the sterilization capacity, without any variation in the overall length of the system.

A better understanding of the present invention will be provided by the

ensuing description and by the attached drawings, which illustrates a non-

limiting example of the invention and in which:

Figs. 1 and 2 are longitudinal cross-sectional views illustrating a scheme

of a sterilization system respectively according to a known arrangement and

according to the present invention;

Figs. 3, 4 and 5 are cross sectional views respectively according to planes of traces Ill-Ill, IV-IV, V-V of Fig. 2; Figs. 6 and 7 are schematic longitudinal cross-sectional views similar to those of Figs. 1 and 2, for other embodiments of the invention;

Fig. 8 is a schematic plan view of the system illustrated in Fig. 2, sectioned according to a horizontal plane of trace VIII-VIII; Figs. 9 and 10 are views similar to that of Fig. 8 for other embodiments of the invention; and

Figs. 11/1 and 11/2 are enlarged views of the detail XI of Fig. 2 in two different operative configurations.

A sterilization tunnel according to the prior art generally comprises a load-bearing structure 1 (Fig. 1) closed externally by means of enclosure panels. The structure mainly defines three working areas; namely, a laminar air flow area 3 with a function of protection, an area 5 for sterilization by means of a laminar flow of hot air, and an area 7 for cooling the containers to a temperature suitable for the subsequent processing steps, typically the step of filling the bottles 8 with a pharmaceutical product. Each of said areas comprises its own casing and communicates with the adjacent areas by means of passage openings. A conveyor belt 9 traverses the tunnel throughout in the direction of the arrow F1 through the three areas described above, and returns back with a bottom branch 9A passing mainly in the lowest part of the structure.

The bottles 8 are deposited on the loading end of the belt 9 in a position corresponding to a feed opening 11 of the first area 3, and come out of the tunnel through an unloading opening of the third area 7, to enter automatically a subsequent treatment apparatus, generally for filling of the bottles. In the first treatment area 3, a fan 15 provided with an outlet filter 17 impinges from above upon the bottles 8 with a laminar air flow according to the arrows F2 to prevent dust entering the bottles while these are. awaiting entry into the sterilization area 5. Special gates 19, 21 separate the area 3 respectively from the outside environment and from the area 5,^" the gates being automatically controllable, the former, 19, for introduction of the. bottles into the tunnel, and the latter, 21 , for enabling passage between the area 3 and the area 5 of separate batches of bottles that are. to undergo treatment The sterilization area 5 has insulated walls 5A which enclose it completely, except for openings 23, 25 respectively for intake from the area 3 and exit to the area 7 of the bottles 8 being treated, said openings being closeable by means of respective gates 21 , 41 which are automatically operated according to the passage of bottles. The gates 19, 21 are normally positioned in such a way that they skim the top surface of the conveyor belt, and only when a batch of bottles is to pass are they automatically raised in a known way, until they graze the top parts of the bottles. A fan 29, set in the top part of the area 5, causes circulation, according to the arrows F3, of air filtered and heated by means of a set of resistors 31 , said air impinging upon the bottles present on the belt 9 so as to heat them to the sterilization temperature, typically 300- 350°C. The cooling area 7 is similar to the intake area 3, and is provided with a fan 33 which, through a filter 35, sends out a laminar flow of filtered air that impinges from above upon the bottles 8 present on the belt 9, but in addition has a heat exchanger 37 of a refrigerating system designed to cool said laminar air flow and to bring the bottles down to a temperature compatible with the subsequent processing steps. The bottles come out of the area 7 through an unloading opening 38. Further gate 41 , 43, which are automatically controllable according to the presence and passage of the bottles, are provided for separating the area 7 respectively from the area 5 and from the processing area downstream.

This type of sterilization tunnel presents the drawbacks listed previously, and in particular the possibility that the return branch 9A of the conveyor belt may take as far as the loading opening 11 polluting substances coming from the bottle-filling step in which the bottles 8 are filled with a product, with possible danger for the operating staff.

A system for sterilization of bottles according to a first embodiment of the invention comprises three treatment modules 103, 105, 107 (Fig. 2) with functions similar to those of the areas 3, 5, 7 described previously. As in the previous case, the modules are equipped with fans and filters for treating the bottles with laminar air flows having respective paths shown in Figs. 3, 4 and 5. The said modules are set alongside one another in succession and are obtained in a modular structure made of steel structural work according to the previously cited patent application filed simultaneously with the present application. According to the present invention, each module is traversed by a conveyor belt of its own, respectively 109A, 109B, 109C, which conveys the bottles, in the direction indicated by the arrows F, from an intake opening of the module, respectively 111, 123, 125, to an output opening of the module, respectively 123, 125 and 139. Said openings are equipped with respective closing gates 119, 120, 142, 143 which are similar and operate in a way similar to the corresponding gates of the tunnel illustrated in Fig. 1. Said belts 109A, 109B, 109C are set one after another and, for smooth passage of the bottles 8 from the active stretch of a belt to the next belt, tangential guide surfaces are provided, such as the ones designated by 110A, 110B in Fig. 11 , which are set in the close vicinity of the end parts set facing one another of the active stretches of contiguous belts. Given the smaller development in length of each belt as compared to the one illustrated in Fig. 1 , each belt requires, for its advance, an accordingly reduced power and is drawn along, by means of a mechanical drive, designated by 114A, 114B, 114C, by a respective motor 112A, 112B, 112C set in the top part of the structure 101. The bottom return branch of each belt is set immediately beneath the corresponding active delivery branch. The heating resistors 131 of the sterilization module are advantageously set underneath the return branch of the corresponding belt 109B, with the advantage that the latter, in addition to being heated by convection, is heated also by irradiation. In this way, cooling of the return branch is prevented, and it is ensured that the bottles will rest on a belt heated at a temperature close to that of the air, thus preventing the bottles from undergoing stresses of a thermal origin.

With the above configuration, any possible return path at a low temperature from the cooling module 107 to the feed module 103 is eliminated, and consequently no longer is there any danger that harmful polluting agents may come into contact with the staff operating in the system. In addition, the conveying system with multiple belts enables, as compared to the case of Fig. 1 , the use of further gates 122, 121 , 141 , 144, which, once the process of treatment of the bottles has been completed and the bottles have been unloaded from the sterilization system, enable closing in a sealed way of the communication openings 111 , 123, 125, 139 and subsequent carrying-out of chemico-physical treatment for depurating each module from any residual pollutant.

A system of the type shown in Fig. 2, which, as has been mentioned, is obtained by means of a modular structure, can be designed with modules 103, 105, 107 having a uniform width, or else with modules having different widths, as illustrated in Figs. 9 and 10. In Fig. 9, the module 107 and the corresponding conveyor belt 109C have a width larger than that of the other two modules and corresponding belts. In Fig. 10, instead, it is the loading module 103 and the corresponding conveyor belt 109A that have a width smaller than that of the subsequent two modules. In this way, with lower speeds of the wider belts and corresponding automatic widening of the bottle fronts, it is possible to obtain for each module an optimal stay time of the bottles, at the same time respecting the modularity of the structure.

In a second embodiment of the invention, three treatment modules 203, 205, 207 (Fig. 6) are present, which are similar to those of the case illustrated in Fig. 2, but only two successive belts for conveying the bottles are used; namely, one, 209A, which traverses only the first module 203, and one, 209B, which traverses both of the other two modules, namely the sterilization module 205 and the cooling module 207. The sterilization system is, otherwise, similar to the one illustrated in Fig. 2.

In a third embodiment of the invention, three treatment modules 303, 305, 307 (Fig. 7) are present, which are similar to those of the case illustrated in Fig. 2, but only two successive belts for conveying the bottles are used; namely, one, 309A, which traverses the first module 303. and the second module 305, and one, 309B, which traverses only the other module 307. the sterilization system is, otherwise, similar to the one illustrated in Fig. 2. Also with the dispositions according to Figs. 6. and 7, the continuity, of connection is avoided along the return branches of the beltsi: between the intake and the output of the sterilization system, thus protecting the operators who load the bottles from any contamination. The above embodiments, as compared to the embodiment illustrated in Fig. 2, afford the additional advantage of a lower fabrication cost, in so far as they have one belt less to be provided with a motor drive. It is understood that the drawing only illustrates a possible exemplification of the invention given purely to provide a practical demonstration of the said invention, which may vary in its embodiments and arrangements without thereby departing from the scope of the underlying idea. The possible presence of reference numbers in the attached claims has the purpose of facilitating reading thereof in the light of the foregoing description and in no way limits the scope of protection represented by the claims.

Claims

1) A continuous sterilization system for sterilizing bottles or other glass containers for pharmaceutical or similar use, comprising a filtered-laminar-air- flow intake module set in a position corresponding to the area where the bottles to be filled are loaded, a laminar-air-flow sterilization module, the air being filtered and heated for sterilization, and a filtered-laminar-air-flow cooling module for supplying cooled bottles to the subsequent packaging steps, the bottles being displaced within said modules by means of conveyor belts, characterized in that at least two belts are provided (109A, 109B, 109C; 209A, 209B; 309A,.309B) which are separate and consecutive in such a way that each belt upstream will discharge, the bottles, by means of tangential connecting surfaces (110A, 11 OB), onto the next belt, and in that at least the belt (109A; 209A; 309A) that traverses the intake module is different and separate from the conveyor belt (109C; 209B; 309B) that traverses the cooling module.

2) The sterilization system according to Claim 1 , characterized in that said belts (109A, 109B, 109C; 209A, 209B; 309A, 309B) have, in addition to the top active branch, also the return branch housed inside the module or modules traversed. 3) The sterilization system according to Claim 1 or 2, characterized in that each of said modules for intake (103), sterilization (105) and cooling (107) has a conveyor belt of its own (109A; 109B; 109C) for conveying the bottles.

4) The sterilization system according to Claim 1 or 2, characterized in that the intake module (203) has a conveyor belt (209A) of its own for conveying the bottles, and in that the other two modules, namely, the sterilization module (205) and the cooling module (207), have a conveyor belt (209B) in common.

5) The sterilization system according to Claim 1 or 2, characterized in that the intake module (303) and the sterilization module (305) have a conveyor belt (309A) of their own in common, and in that the other module, namely, the cooling module (307), has an individual conveyor belt (309B).

6) The system according to any one of Claims 1 to 5, characterized in that the heating resistor (131) of the sterilization module (105) is set underneath the return branch of the corresponding conveyor belt (109B).

7) The system according to any one of Claims 1 to 6, characterized in that each conveyor belt (109A, 109B, 109C; 209A, 209B; 309A, 309B) of the conveying system is driven by means of a motor (112A, 112B, 112C) set above and outside the corresponding treatment module, a mechanical drive (114A, 114B, 114C) being provided between said motor and the corresponding belt.

8) The system according to any one of Claims 1 to 7, characterized in that it comprises a modular structure made of steel structural work.

9) The system according to any one of Claims 1 to 8, characterized in that the widths of each module (103, 105, 107) and of the corresponding conveyor belt (109A, 109B, 109C) are chosen according to the stay time of the bottles in the module itself, irrespective of the widths of the adjacent modules.

10) The sterilization system according to any one of the foregoing claims, characterized in that between consecutive belts, in particular between the respective tangential connecting surfaces (110A, 110B), there is provided a gate (121, 141) which is designed to close in a hermetically sealed way the corresponding connection opening for connection between adjacent modules.

11) The sterilization system according to Claim 10, characterized in that said gate (121 , 141) can be excluded by lowering it so that it is flush with said connecting surfaces (110A, 110B), and in that said gate is set in operation - for closing said opening in a sealed way - by raising it by means of a remotely controlled actuator.

12) A sterilization system for continuous sterilization of containers made of glass or the like for pharmaceutical or similar use; the foregoing as herein described and as represented by way of example in the attached drawings.