FR2961124A1 - ASSEMBLY FOR THE PRODUCTION OF CONTAINERS USING AN INSTALLATION COMPRISING AN AIR RECYCLING CIRCUIT AND RECYCLING METHOD - Google Patents

Abstract

The present invention relates to a recycling process and an assembly comprising an installation (10) which, implanted in an industrial premises (16) of volume (V), comprises a circuit (62) for recycling the cooling air implemented. in the oven (26), said circuit (62) being adapted to recycle at least a portion of the filtered air extracted by said extraction means (54) by reintroducing said air into the industrial premises (16).

Description

i

The present invention relates to an assembly for the production of containers by means of an installation comprising a recycling circuit. air and a recycling process. The present invention more particularly relates to an assembly for the production of containers comprising at least: a building comprising a closed industrial premises delimiting a volume of ambient air; an installation, installed in said industrial premises, for the manufacture of containers from thermoplastic preforms, comprising at least one protective enclosure intended to isolate an interior volume of the installation with respect to the ambient air and comprising at least: a preform thermal conditioning unit arranged in said interior volume and consisting of an oven comprising heating means and at least one cooling device, said cooling device comprising air supply means which, associated with means for filtering the ambient air, are able to deliver a filtered air for the air cooling of at least part of the preforms in transit inside the furnace, and 25 - an extraction system for air associated with the furnace which comprises extraction means able to extract the cooling air out of the interior volume of the oven and to evacuate said air after s cooling. Such an assembly is known from the state of the art, in particular factories or production units, for the production of containers forming a hollow body, in particular bottles, flasks, etc.

The containers are made from preforms or blanks previously obtained by injection of thermoplastic material, for example PET (PolyEthylene terephthalate), these preforms being then thermally conditioned and then converted into the manufacturing facility of said assembly for production. Such an installation for manufacturing containers from thermoplastic preforms generally comprises, in addition to at least one thermal conditioning unit, at least one preform conversion unit into containers and a container filling unit obtained from said transformed preforms. , said units also being arranged in the interior volume delimited by the protection enclosure of the installation.

The preforms are conditioned thermally in a furnace forming the thermal conditioning unit of the installation to allow their subsequent processing into a container in the next unit, in particular by a forming operation by means of a fluid under pressure.

The forming operation of the preform is for example carried out by means of a gas under pressure, such as air, to obtain the container by blowing or by stretch-blow molding or at least partly by filling by means of a liquid under pressure.

The thermal conditioning requires the combined application, during a given period of time, of heating on the body of the preform, for example by infrared radiation emitted by the heating means and also an air cooling of said body.

Air cooling has the effect of promoting radiation heating by moderating the effects of heat conduction through the air mass contained in the oven so as to avoid any crystallization and allow the establishment of a gradient in the wall body that is such that the wall has temperature on its inner surface greater than or equal to the temperature of its outer surface. This is the reason why, the oven of such an installation comprises an air cooling device intended to cool, by application of a flow of cooling air, at least the body of the preforms that pass through the parade at the same time. inside the oven following a determined heating path. In addition to air supply means for establishing said flow of cooling air inside the furnace heating zone, the cooling device comprises air filtration means which are associated with said heating means. 'food. The filtration means are intended to remove impurities (dust, micro-organisms, etc.) from the air so as to deliver to the preforms a cooling air which is filtered air having a degree of cleanliness as high as possible. . According to the state of the art for the applicant, the oven is also equipped with an air extraction system for extracting the air, after cooling, to evacuate said air towards the outside of the industrial premises. installation of the installation, generally to the atmosphere so as to evacuate with this air the calories resulting from the heating carried out in the oven. To do this, the extraction system comprises extraction means, such as a fume hood, and an air exhaust duct, one end of which is connected to the extraction means and the other end of which leads to the outside of the industrial premises, especially in the atmosphere. Therefore, respectively drawn from the industrial premises by the supply means and filtered by the filtering means of the cooling device equipping the oven, the ambient air is then discharged by the extraction system outside the room. industrial in particular to evacuate heat. With regard to the present invention, the Applicant was first able to discover that the origin of many problems, especially the cleanliness of the containers manufactured, were attributable to the importance of air exchange occurring in the industrial premises. implementation of the installation and then that these incoming / outgoing air exchanges in the room are related to the ambient air consumption of the cooling device and the associated extraction system. Indeed, the ambient air sucked by the supply means of the cooling device is then removed, after cooling, to the outside of the industrial premises by the extraction means and in particular to the atmosphere, but this evacuated air is 15 instantly replaced in the industrial premises by an equivalent volume of air. Thus, at least part of the ambient air contained in the industrial premises is constantly renewed by air coming from outside the industrial premises, mainly by atmospheric air lying outside. of the factory building or production complex housing the industrial premises. An incoming volume of atmospheric air therefore replaces in the total volume of the industrial premises the volume of ambient air which has been drawn therefrom before being discharged to the outside by the extraction system. However, atmospheric air entering the industrial premises from outside is an air with uncontrolled and generally very variable quality parameters. More specifically, the temperature of the air, its degree of humidity or even and especially the undesirable presence of bacteria such as dust are not controlled and are all parameters which it is however perfectly understood that they directly influence the quality of manufacture of containers. Moreover, such parameters vary according to the geographical location of the building including the installation, see - for the same location - depending on the season which is likely to modify some of these qualitative parameters such as the temperature of the air which can vary with a strong amplitude on the same day. The aforementioned problems are therefore essentially the impact lo of the variations of the qualitative parameters (temperature, humidity, etc.) of the atmospheric air renewing the ambient air coming out of the industrial premises which affect the thermal conditioning process but more particularly the cleanliness (dust, bacteria, ...) of this air. Indeed, given the volume of atmospheric air entering, the Applicant has been able to establish that this replacement of the ambient air, instead of the air evacuated, by this atmospheric air generally not clean leads to a degradation of filtration means implemented, see incidentally the quality of manufacture of the containers, especially the cleanliness of the final containers. The air exchanges entering / leaving the industrial premises have, among other consequences, a rapid fouling of the filtration means of the cooling device resulting in a decrease in their efficiency or at least a reduction in the duration of use of the means. filtration and an increase in the frequency of maintenance operations requiring a complete shutdown of the manufacturing facility. These air exchange problems therefore also have a direct economic impact on the operating costs of the container manufacturing facility. To control the quality of the ambient air of the industrial premises, it is possible to resort to a transformation of the industrial premises to make what is commonly called a "clean room", that is to say a sealed enclosure designed to to eliminate as much as possible dust and micro-organisms, to obtain ultra-clean manufacturing industrial conditions in the industrial premises. However, it will be readily understood that if such a transformation is still possible, the costs associated both for the transformation of the industrial premises and later for the operation of the installation are very expensive. In addition, however, only a part of the problems related to the quality of manufacture are solved when the operating costs will be increased, in particular all the costs corresponding to the means implemented to achieve such an improvement. White room. The object of the present invention is in particular to overcome the aforementioned drawbacks and to provide a particularly economical installation for the operation, while improving the quality of the containers and more particularly the cleanliness of the containers manufactured. For this purpose, the invention proposes an assembly for the production of the type described above, characterized in that the installation comprises a cooling air recycling circuit able to recycle at least a portion of the extracted filtered air. by said extraction means by reintroducing said air into the industrial premises. Advantageously, the filtered and extracted air, called recycled air, is reintroduced directly into the volume of the industrial premises of installation of the installation. Advantageously, a recycling circuit according to the invention 30 makes it possible to recycle the air filtered by the air cooling device fitted to the oven, that is to say to use directly again "looped" the filtered air after first use in the oven for cooling purposes.

The recycled cooling air has particularly advantageous qualities with respect to the air, in particular atmospheric air, previously admitted in the industrial space to compensate for the air completely evacuated, to the atmosphere, outside the industrial premises. . In fact, recycled air presents above all a particularly high degree of cleanliness, dust, bacteria, etc. having been removed during the filtration operation performed by the filtering means of the cooling device. Moreover, as it passes through the oven, the cooling air dries out under the effect of the heat prevailing inside the oven so that a dehumidification of the air is obtained without having to resort to additional means. Thanks to the recycling according to the invention, the renewal of ambient air is suppressed by incoming air whose parameters have not been controlled, and the renewal is carried out with filtered air, or with recycled air having especially a high degree of cleanliness. Advantageously, the parameters of the ambient air of the industrial premises 20 are therefore better controlled so that the quality of the containers produced by the installation is improved. Advantageously, the recycling circuit is provided with means for regulating the temperature of the recycled air, alternatively the industrial premises is provided with such means for regulating the temperature of the ambient air, in order to maintain the temperature of the air. in a range of temperature values ensuring optimum manufacturing conditions. According to the invention, recirculated air is reintroduced into the industrial premises instead of the ambient air consumed by the cooling device supply means, and the recycled air that renews the ambient air is therefore likely to be used again, in particular again by these same means for supplying the cooling device and so on following a loop circulation of air between the industrial premises and the inside of the oven. Advantageously, the recycling circuit according to the invention makes it possible to treat the ambient air by using existing means so that there is no need to resort to specific additional means, such as those of a clean room. Moreover, thanks to such a circuit and the recycling process, the ambient air contained in the industrial premises is an air whose cleanliness will increase with the time of operation of the installation. Indeed, the ambient air drawn by the furnace cooling device in the industrial premises is cleaner to each of its passages through filtration means of said cooling device. Advantageously, the extraction means of the recycling circuit are put into operation for a given period of time before the manufacture of the containers actually begins and this in order to improve the cleanliness of the ambient air contained in the industrial premises. Thus, when the thermal conditioning of the preforms begins in the manufacturing plant, followed by the transformation of the preforms into containers, the ambient air drawn by the cooling device is then an air having a high degree of cleanliness because of have been previously filtered, the degree of cleanliness being determined in particular by the filtration means used. In general, the degree of cleanliness is one of the quality parameters, in particular very controlled in the context of agri-food applications using such containers. In addition, the fouling of all the filtration means equipping the facility is reduced and their efficiency as their service life increased to the benefit of a reduction in associated operating costs.

Advantageously, the recycling circuit according to the invention thus also makes it possible to obtain substantial economic benefits, in particular because of the reduction in the frequency between the maintenance operations or changes in the filtration means and the increase in the overall duration of use of the filtration means. According to other characteristics of the invention: the recycling circuit comprises at least extraction means for extracting the filtered air introduced inside the furnace by the air cooling device; - The recycling circuit comprises at least one main conduit, an upstream end is connected to the extraction means and a downstream end opens into the industrial premises to reintroduce said filtered air extracted from the oven; The extraction means of the recycling circuit comprise at least one hood which, with a complementary part of the enclosure, is able to confine the interior volume of the oven to isolate it from the ambient air and at least one fan; able to extract the filtered air present in the interior volume of the oven to recycle said air in the industrial premises via said recycling circuit; the recycling circuit includes at least one evacuation duct, one end of which is connected to the extraction means and the other end of which discharges outside the industrial premises, in particular into the atmosphere, and the recycling circuit; comprises regulating means which are able to selectively distribute the extracted air in the evacuation duct and / or in the main duct; the recycling circuit comprises at least one control unit able to control the extraction means and the supply means so that the volume of air extracted by the extraction means is greater than the volume of ambient air 2961124 lo

drawn by the supply means of the cooling device in the volume industrial premises; the recycling circuit comprises air cooling means which are capable of being selectively controlled to regulate the temperature of the recycled air so that the temperature of said recycled air, intended to be reintroduced into the industrial premises, is less than or equal to a set temperature determined to maintain the ambient temperature of the air in the industrial premises in a given temperature range; the extraction means are capable of establishing a circulation of air in a loop between the volume of the industrial premises and the interior volume of the oven with a factor corresponding to the ratio of the volume of air extracted out of the oven by the extraction means; 15 on the volume of the industrial premises which, for a given unit operating time, is greater than or equal to 1; the extraction means are controlled so as to establish a factor of between 2 and 20, preferably between 8 and 12. The invention also proposes a process for recycling air in an installation located in an industrial premises. method of making containers from preforms, comprising at least the steps of successively: (a) filtering ambient air to obtain filtered air suitable for use in air cooling at least a portion of the preforms during thermal conditioning in an oven of the plant; (b) extracting the filtered air out of the oven, particularly after using said air for cooling; (C) recycling at least a portion of said filtered air extracted from the furnace by reintroducing at least a portion of said air into said industrial premises.

Thanks to the air recycling process, it eliminates the air exchange phenomenon during which the ambient air is renewed by atmospheric air and the degree of cleanliness of the air is particularly increased and therefore that of manufactured containers. Advantageously, the recycling process comprises at least one step of controlling the extraction means to establish a loop air circulation between the volume of the industrial premises and the inside of the oven with a factor corresponding to the ratio of the volume of the air extracted out of the oven by the extraction means on the volume of the industrial premises which, for a given unit operating time, is greater than or equal to 1. Advantageously, the steps of the recycling process are implemented in an installation comprising a recycling circuit 15 according to the teachings of the invention. Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: FIG. 1 is a schematic view from above which partially represents a example of an assembly for the production of containers comprising a container manufacturing facility located in an industrial premises of a building of said assembly; FIG. 2 is a perspective view which represents the assembly according to FIG. 1 and which illustrates the recycling circuit according to one embodiment of the invention; - Figure 3 is a cross sectional view showing the oven and illustrating said embodiment of the 3o recycling circuit according to the invention. In the description and the claims, the terms "front" or "rear" will be adopted by convention and in a nonlimiting manner with reference to the longitudinal direction, "upper" and "lower", with reference to the vertical direction and according to the gravity terrestrial, and the longitudinal, vertical and transverse directions with reference to the trihedrons (L, V, T) indicated in the figures. The terms "upstream" and "downstream" will be used with reference to the flow direction of the air flow in the installation and / or in the air recycling circuit. FIG. 1 shows diagrammatically an assembly 5 for the production of containers 12 from a thermoplastic preform 14.

The assembly 5 or production plant comprises a building (not shown) comprising a closed industrial premises 16 delimiting a volume V of ambient air and an installation 10 for the manufacture of said containers 12 which is located in said industrial premises 16.

By industrial premises 16 "closed" means here enclosed by walls and a roof so that the volume V is determinable, so closed does not mean that the room is devoid of access means (such as doors), the Industrial premises 16 is therefore not "open to all winds" so that the volume V of ambient air effectively constitutes an external environment around the installation 10. FIGS. 1 and 2 illustrate, in a nonlimiting manner, a example embodiment of such an assembly 5 and, more particularly for Figure 1, the installation 10 according to the state of the art for the applicant. FIG. 1 shows in detail an example of preform 14 for the manufacture of a container 12 forming a hollow body, such as here a bottle, intended to be thermally conditioned and then transformed to obtain said container 12.

By definition, the term "container" hereinafter denotes both the final container obtained by a single-stage forming process of a preform directly leading to the final container, such as the bottle illustrated in detail. in Figure 1, an intermediate container obtained in the case of implementation of a forming process with several stages of transformation. The installation 10 is located in an industrial premises 16 advantageously closed located in a building (not shown) of a production unit 5, the ambient air contained in the industrial premises 16 of volume V constituting the environment outside the installation 10. For the implementation of the present invention, it is important that the industrial premises 16 is closed as explained above and this to constitute for the installation 10 a "reservoir" of ambient air , of given volume V. Advantageously, the installation 10 comprises at least one enclosure 18 of protection of the installation intended to isolate, with respect to the ambient air of the industrial premises 16 of implantation of the installation 10, an internal volume 20 inside. which the various means of manufacturing the containers 12 are arranged. The installation 10 comprises a system 22 for supplying preforms 14, not shown in detail.

Alternatively, the installation 10 may be provided with a decontamination module by applying a sterilizing agent to treat the preforms 14, in particular by means of a jet of dry steam to cause condensation deposition. a uniform steaming film of sterilizing agent on at least the inner wall of the preforms 14 to be sterilized. The installation 10 comprises at least one thermal conditioning unit constituted by at least one oven 26. The supply system 22 is arranged upstream of an inlet E of the oven 26, arranged in the enclosure 18 of protection, at the level of of which the preforms 14 are transferred by a transfer wheel 24 to a conveying device 28 fitted to the furnace 26.

The conveying device 28 is for example constituted by an endless chain carrying means for supporting the preforms 14, for example "spinettes", said device 28 being intended to transport the preforms 14 along a determined heating path ending at the output of the furnace 26. Without limitation, the furnace 26 here has a heating path in "U" comprising two longitudinal heating sections parallel, one go, the other return, connected to each other by a transverse curvilinear section , called stabilization. The thermal conditioning unit of the installation 10 formed by the furnace 26 mainly comprises heating means 30 and at least one air cooling device 34, said device 34 being intended for cooling by air at least a portion of the preforms 14. , such as the body (and the bottom). Advantageously, the cooling device 34 is able to cool by air on the one hand the bodies of the preforms 14 in transit along the heating path and, on the other hand, the necks of the preforms 14 as well as the adjacent mechanical members, while particularly the support means of the preforms 14. The cooling device 34 comprises means 32 for supplying air, such as fans, arranged to deliver said cooling air over all or part of the heating path.

The cooling device 34 comprises filtering means 36 for filtering the air intended for cooling. Preferably, the support means ("spinners") of the conveying device 28 are able to rotate each of the preform 14 in rotation in order to promote an appropriate distribution of the heat in the body of each preform 14. After their conditioning by the furnace 26, the preforms 14 are transported from the furnace outlet 26 to a unit 38 for converting the preforms 14 into containers 12, for example by means of at least one transfer wheel 35. Advantageously, the processing unit 38 is here constituted by a blowing machine (called "blower").

In the example shown in FIG. 1, the blowing machine is of the rotary type and comprises a carousel 40 equipped with a plurality of stations which are distributed circumferentially and which are each provided mainly with means 42 for molding and, for example, with means Additional blowing or stretch blow molding (not shown) Preferably, the containers 12 obtained are then transported, for example by transfer wheels 44, 46, to a filling unit 48. Advantageously, the filling unit 48 comprises at least one filling machine 50 and preferably also a sealing machine 52, said machines 50, 52 (not shown in detail) being able to successively fill the containers 12 and then to the closure of the containers 12 filled, for example by means of 20 screw caps complementary to the necks. Preferably, the filling unit 48 is juxtaposed with the processing unit 38 so as to obtain a compact installation in which the entire manufacturing process is carried out until the finished containers 12 are filled and closed, see labeled. The containers 12 are for example conveyed to an outlet S by a transfer wheel 51 and are then capable of being packaged, in particular batched, packaged and palletized, for their shipment for marketing purposes. As illustrated in FIG. 1, the enclosure 18 of the installation 10 delimits a general internal volume 20 in which all the units 26, 38, 48 are arranged for the manufacture of the containers 12 which have just been described and which are thus confined, isolated from the ambient air of the industrial premises 16 forming the external environment around the installation 10. The enclosure 18 (represented by a strong line in FIG. 1) is for example constituted by a set of vertical walls formed by panels and at least one horizontal wall to form a ceiling covering the entire installation 10. Advantageously, the installation 10 comprises an air extraction system associated with the furnace 26 which comprises means 54 d extraction to extract the cooling air from the inner volume of the oven 26 and to evacuate said air after its use for cooling. For this purpose, the extraction system comprises, for example, a discharge duct 56, the outlet of which opens out from the industrial premises 16, generally into the atmosphere.

Preferably, the extraction means 54 comprise at least one extraction hood 58 incorporating ventilation means 60, such as at least one fan. When the installation 10 is already provided with such an extraction system the implementation of an air recycling circuit according to the invention is particularly facilitated since said circuit is likely to be obtained by modifying such an existing extraction system. With reference to FIGS. 2 and 3, a plant 10 of the type previously described in FIG. 1 and installed in an industrial premises 16 of volume V will now be described more particularly, said installation 10 illustrating in a nonlimiting manner an embodiment of a recycling circuit 62 according to the invention. According to the invention, the installation 10 comprises a circuit 62 for recycling the cooling air which is able to recycle at least a portion of the filtered air extracted by extraction means 54, such as said means 54. extraction, reintroducing said air into the industrial premises 16.

Advantageously, the filtered air extracted by said extraction means 54 is directly reintroduced into the industrial premises 16. Advantageously, the recycling circuit 62 comprises extraction means, such as said extraction means 54, for extracting the filtered air, introduced inside the furnace 26 by the air cooling device 34, in order to recycle said filtered air into the recycling circuit 62 and to reintroduce it directly into the industrial premises 16. When the installation 10 is of the type described above, the recycling circuit 62 is thus made by modifying the prior extraction system. However, it is a new application of the prior means to obtain a recycling circuit 62 according to the invention. The means 54 for extracting air are here intended to extract the cooling air out of said internal volume defined by the part of the enclosure surrounding the oven but to allow the recycling of said air in the volume V of the industrial premises 16 and no longer to the outside, ie to the atmosphere. Preferably, the means 54 for extracting the recycling circuit 62 comprise at least one hood, such as the hood 58. The hood 58 is complementary to a part of the enclosure 18 so as to confine the internal volume 20 of the oven 26 to isolate it from the ambient air. Advantageously, the extraction means 54 comprise at least one fan 60 adapted to extract by vacuum the filtered air present in the interior volume of the oven 26 to allow the recycling of said air in the industrial premises 16. Preferably, the circuit 62 recycling comprises at least one main conduit 64, an upstream end is connected to the extraction means 54 and a downstream end opens into the industrial premises 16 to reintroduce the filtered air extracted from the oven 26.

When the recirculation circuit 62 comprises a discharge duct 56, the main duct 64 is advantageously connected to said evacuation duct 56. Such an exhaust duct 56 may be maintained or removed in accordance with the desired configuration of the recycling circuit 62. Thus, in the event of the removal of a downstream portion of the evacuation conduit 56 intended to convey the extracted air to the outside, the upstream portion of the conduit 56 remaining advantageously constitutes said main conduit 64. As illustrated in FIG. 2, the recirculation circuit 62 preferably comprises at least one evacuation duct 56, one end of which is connected to the extraction means 54, in particular the hood 58, and the other end of which opens out at the end. Outside the industrial premises 16, especially in the atmosphere, the main conduit 64 of the circuit 62 is connected to the discharge conduit 56. Preferably, the main conduit 64 of the circuit is connected to the evacuation conduit 56, downstream of the junction of the evacuation conduit 56 with the extractor hood 58. Advantageously, the recycling circuit 62 then comprises means 66 for regulating the flow of air which are able to selectively distribute the extracted air in the evacuation conduit 56 and / or in said main conduit 64. The regulation means 66 consist, for example, of at least one flap which is mounted inside at least one duct of the recycling circuit 62, here at the connection junction between the evacuation duct 56 and the main duct 64, so as to be able to selectively close the circulation of the air flow in one or the other of the ducts 56, 64. Preferably, the flap 66 forming the control means is pivotally mounted between at least two extreme positions, a first position P1 and a second position P2.

In the first position P1 shown in strong lines in FIG. 3, the shutter 66 completely closes the section of the evacuation duct 56 so that the extracted air flow then circulates integrally in the main duct 64 so as to be recycled in the industrial premises 16. In the second position P2 shown in dashed line in Figure 3, the flap 66 extends vertically and completely closes the section of the main duct 64 so that the extracted air flow then circulates integrally in the duct 56 evacuation opening outside the industrial premises 16, no recycling then being performed in the room. The flap 66 is able to occupy intermediate positions between the said extreme positions P1 and P2, such as the position PO illustrated in FIG. 3, so that the recycling is then partial and only a part of the filtered airflow extracted is reintroduced into the volume V of the industrial premises 16. Advantageously, a conduit 56 for evacuation and means 66 for regulation implemented can be used to achieve a thermal regulation of the recycled air through the recycling circuit 62 . Advantageously, the recycling circuit 62 comprises air cooling means 68 which can be selectively controlled to regulate the temperature of the air. Preferably, the cooling means 68 consist of an air-fluid-type heat exchanger which is able to cool the recycled air passing therethrough by means of a coolant, for example water with or without additive. The cooling means 68 are for example arranged in the main conduit 64 of the recycling circuit 62, upstream of the outlet of said duct 64 through which the extracted filtered air, said to be recycled, is reintroduced into the industrial premises 16. such means 68 for cooling the recycled air, the recycling circuit 62 is able to control the temperature of said air to be reintroduced in the industrial premises 16, so that the temperature of said air is less than or equal to a set temperature determined in order to maintain the ambient temperature of the air in said industrial premises 16 in a given temperature range, for example between 15 ° C and 35 ° C, preferably around 20 ° C. Advantageously, the regulation means 66 are able to be controlled in combination with said cooling means 68 for regulating the ambient air temperature of the industrial premises 16 in the volume V of which all or part of the air is recycled by the intermediate of the recycling circuit 62. Advantageously, the recycling circuit 62 comprises at least one control unit 70 able to control the extraction means 54 and the supply means 32.

Preferably, the recycling circuit 62 comprises at least one control unit able to control the regulation means 66 and / or the cooling means 68, said unit being for example constituted by the control unit 70. The means 60 for ventilating the extraction means 54 are driven by a motor 72. Advantageously, the motor 72 for driving the means 60 for ventilating the extraction means 54 is associated with a speed variator 74 which is adapted to be controlled by the control unit 70.

The means 32 for supplying air to the cooling device 34 consist, for example, of at least one fan 76 which is driven by a motor 78. Advantageously, the motor 78 for driving the supply means 32 is associated with a variator 80 speed which is able to be controlled by the control unit 70. Advantageously, the control unit 70 of the recycling circuit 62 is able to control the extraction means 54 by controlling the speed variator 74 associated with the motor 72 driving the ventilation means 60 and to drive the power supply means 32. controlling the speed variator 80 associated with the motor 78 driving the fan 76. Advantageously, the control unit 70 controls the drives 74 and 80 so that the volume Ve of air extracted by the extraction means 54 is greater than the volume Va of ambient air drawn by the supply means 32 of the cooling device 34 in the industrial premises 16 of volume V. To do this, the control unit 70 operates at least one signal S1 representative of the extracted air flow rate which is provided by at least one sensor 82 arranged in the recycling circuit 62, for example downstream of the fan 60, and a signal S 2 representative of the air flow sucked by the supply means 32 and which is supplied by ar at least one sensor 84 preferably arranged in the cooling device 34, downstream of the filtering means 36. Advantageously, the filtering means 36 of the cooling device 34 are constituted by so-called "absolute" filters, such as "ULPA" or "HEPA" type filters. It will be recalled that an ULPA filter for "Ultra Low Penetration Air" is called in English: very low penetration air filter, and a "HEPA" filter for "High Efficiency Particulate Air" is called in French: air filter very high efficiency. Preferably and as illustrated by the cross section of the oven 26 in FIG. 3, the filtration means 36 comprise at least one pre-filter 86 which is here arranged in the vicinity of an inlet mouth 88 disposed in the enclosure 18 and a filter 90 arranged downstream of the pre-filter 86, the passage section of the pre-filter 86 being greater than the passage section of the filter 90.

Preferably, the pre-filter 64 is a gravimetric filter, which is capable of filtering so-called coarse particles, which are of a determined diameter, for example greater than ten microns. Advantageously, the filter 68 is an "absolute" filter of one of the aforementioned types, which is capable of filtering so-called fine particles, for example with a diameter greater than one micron. We will now more particularly describe the operation of the recycling circuit 62 according to the embodiment of the invention. In the installation 10, the circulation of the air in the oven 26 begins with the suction of ambient air which is drawn from the volume V of the industrial space 16 by the air supply means 32 of the device 34. cooling. More specifically, the ambient air is sucked by the depression 15 caused by the rotation of the fans 76 that includes the oven 26 and which are for example distributed longitudinally as shown in Figure 1. The sucked ambient air successively passes through the intake ports 88, pre-filters 86 and filters 90 to a plenum 92 of the cooling device 34 forming a filtered air reservoir for cooling. The corresponding air flow is illustrated in FIGS. 2 and 3 by arrows "A" through the cooling circuit formed by the means of the air cooling device 34 of at least a portion of the preforms 14. In the interior of the furnace 26, the filtered air is brought to the heating zone of the preforms 14 where it comes in particular in contact with the bodies of the preforms 14 to effect the cooling of the external surface of the wall of the body. The cooling air is then withdrawn from the furnace 26, from the interior of the furnace 26, by the air extraction means 54 of the recycling circuit 62.

Preferably, and as shown in FIG. 3, the flap 66 occupies the position P1 in which it closes off the section of the evacuation duct 56 so that the air extracted by the fan 60 from the extraction means 54 travels main conduit 64 of the recycling circuit 62 until its reintroduction into the volume V of the industrial premises 16. When the flap 66 occupies said position P1, the circulation of the recycled air is effected as it would be carried out in a circuit 62 recycling device without evacuation conduit 56 and lo having only a main conduit 64. Advantageously, the filtered air thus extracted is then completely reintroduced into the industrial premises 16 for implantation by the recycling circuit 62. As previously explained, the quantity of ambient air 15 drawn from the industrial premises 16 by the cooling device 34 of an installation 10 is returned to the industrial premises 16 in the form of recycled air, which is advantageously filtered air whose degree of cleanliness is much higher than the initial one of the ambient air. Advantageously, the invention proposes recycling the cooling air extracted from the furnace in order to suppress the renewal of the ambient air by atmospheric air, while advantageously taking advantage of the fact that this air is filtered air to improve the quality of the containers manufactured and especially the degree of cleanliness. The invention also proposes a process for recycling air in a production unit 5 which comprises a building comprising a closed industrial premises 16 delimiting a volume V of ambient air, and an installation 10 located in the industrial premises. 16, for the manufacture of containers 12 from preforms 14, the recycling process comprising at least the steps of successively: (a) filtering ambient air to obtain filtered air suitable for use in air cooling at least part of the preforms 14 during the thermal conditioning carried out in an oven 26 of the installation 10; (b) extracting the filtered air out of the oven 26, especially after using said air for cooling; (c) recycling at least a portion of said filtered air extracted from the furnace 26 by reintroducing at least a portion of said air into said industrial premises 16.

According to the recycling method according to the invention, the air filtered by the cooling device 34 is recycled, that is to say introduced directly into the industrial premises 16 for the installation of the installation 10 so that it can be used again, in loop, as ambient air.

Thanks to the invention, the ambient air contained in the industrial premises 16 is an air whose cleanliness will increase with the operating time of the installation 10, dust, bacteria, etc. being eliminated by successive filtration operations. Advantageously, the quality of the ambient air resulting from the implementation of recycling according to the invention makes it possible to increase the quality of manufacture of the containers obtained with such an installation, in particular the degree of cleanliness of the containers 12. Advantageously, a 94 air blowing system is associated with the processing unit 38 comprising here a blowing machine, said system 94 being integrated in an upper part of the chamber 18 forming a ceiling. This insufflation system 94 is intended to inject air into the associated part of the internal volume 20, isolated from the external environment by a part of the enclosure 18, and this in order to establish an overpressure to reduce effectively the risks of pollution from outside, including airborne particles.

The insufflation system 94 thus draws from the industrial premises 16 a given volume of ambient air which is symbolized by the arrow "B" in FIG. 2. A similar air insufflation system 96 equips the unit 48 with filling to also establish an overpressure inside the corresponding portion of the internal volume 20 defined by the chamber 18, the ambient air drawn into the industrial premises 16 by the system 96 insufflation is symbolized by an arrow " C "in Figure 2. lo Through the recycling of the cooling air used in the oven 26 for thermal conditioning, the blowing systems 94 and 96 draw respectively into the volume V of the industrial premises 16 ambient air which is cleaner so that the air blown to the pressurization is an air whose rs degree of cleanliness is improved. Advantageously, the degree of cleanliness of the air with which the preforms 14, then the containers 12 are in contact within the installation is homogeneous through the different units of the installation 10. Advantageously, it also limits fouling the filtration means integrated blowing systems 94, 96, with the same economic benefits as those detailed above for those 36 of the device 34 cooling. Advantageously, the extraction means 54 are capable of establishing a circulation of air in a loop between the volume V of the industrial premises 16 and the interior volume of the oven 26 with a factor F corresponding to the ratio of the volume Ve of air extracted. out of the furnace 26 by the extraction means 54 on the volume V of the industrial premises 16 which, for a given unit operating time, is greater than or equal to one, ie F = 1. Advantageously, the given unit operating time is equal to one hour.

Preferably, the factor F = Ve / V is between two [F = 2] and twenty [F = 20]. To do this, the extraction means 54 are controlled by the control unit 70, in particular as a function of the signals S1 and S2. In order to illustrate the advantages of the invention, the air consumption or flow rates of a manufacturing installation of the type of that described with reference to FIGS. 1 and 2 will be detailed below. limiting the consumption of air or air flow sucked by a system 94 insufflation is of the order of 8000 m3 per hour, while that of the system 96 insufflation is of the order of 10,000 m3 per hour . Even more important is the air consumed by the air cooling device associated with the furnace 26 since, for example, values of the order of 20,000 to 30,000 m 3 per hour are attained depending on the type of furnace, particularly the furnace. number of heating module. For a furnace 26 of modular design, the consumption of air 20 per heating module is of the order of 1300 m3 per hour, the furnace may comprise for example twenty modules. The air consumption of an installation 10 is therefore of the order of 30,000 to 50,000 m 3 per hour with generally at least or more than half of the air for the single air-cooling device 34 of the furnace 26. It will therefore easily understand the importance of the problems previously encountered due to the evacuation of the cooling air to the outside and its replacement with atmospheric air. Thus, by way of nonlimiting example, if we consider an industrial premises 16 generally parallelepipedic having dimensions of 6 m for the height, 15 m wide and 30 m long respectively, we obtain a volume of 2700 m3. The volume of 2700 m 3 of ambient air of the industrial premises 16 constitutes a "reservoir" in which the air required for the installation 10 is drawn by the cooling device 34 and is then discharged outside the industrial premises 16. Conversely, the ambient air consumed by the insufflation means 94, 96 for the overpressure of the units 38, 48 escapes in such a way that said air used is permanently restored through the chamber 18. In considering an air consumption equal to 27,000 m3 per hour for the single cooling device 34 whose air is now recycled through the recycling circuit 62, this means that the ambient air contained in the volume V of the industrial premises 16 is be renewed more than ten times in an hour of time with recycled air. In this example, the factor F is therefore equal to ten [F = 10]. The recycling circuit 62 will therefore act as a "lung" to treat the ambient air, especially the cleanliness of the air, drawing the ambient air before returning it after the recycling in the form of filtered air of higher degree of cleanliness. Advantageously, the factor F is between eight [F = 8] and twelve [F = 12], for example equal to ten [F = 10] as in the preceding example. Advantageously, the recycling according to the invention implements means such as the filtering means 36 of the cooling device 34 which are means which already exist, at least in the installations 10 of the applicant. Thus, there is no need for additional resources and a fortiori a clean room.

Therefore, the implementation of recycling according to the invention offers an alternative solution particularly interesting economically compared to such a clean room.

In fact, in an installation 10 comprising a recycling circuit 62 according to the invention, by eliminating the evacuation of the cooling air towards the atmosphere, the volume V of ambient air of the industrial premises 16 will be renewed with recycled air more and more clean. lo advantageously, the volume Ve of air extracted by the extraction means 54 is greater than the volume Va of ambient air drawn by the supply means 32 of the cooling device 34 in the industrial premises 16 of volume V so as to to avoid any entry of ambient air into the volume 20 through the chamber 18. The recirculation of the air according to the invention has the effect of suppressing the air intake which previously led to Atmospheric air enters the industrial premises 16 in compensation for the air discharged into the atmosphere. Advantageously, the recycled air having been filtered by the filtration means 36, the recycled air delivered by the circuit 62 is an air having a degree of cleanliness which, determined by the filtering means employed, is greater than the initial one of Ambiant air. Once recycled in the industrial premises 16, this air forms part of the ambient air and is then likely to be sucked back by the cooling device 34. It will therefore be understood that at each passage or loop through the recycling circuit 62 of the installation 10, the air returned at the outlet is an increasingly clean air. For this reason, the recycling of the air produced in accordance with the teachings of the invention makes it possible to improve the quality of the containers 12 manufactured, which thus have a particularly high degree of decontamination or sterility. Advantageously, the recycling of the cooling air according to the invention makes it possible to reduce the fouling of the filtration means 36 like filtering means generally integrated with the insufflation systems 94, 96 of the units 48, 38, and to reduce the frequency of maintenance interventions. The quality of the ambient air is substantially increased when the recycled air is still automatically dehumidified by the heating means of the oven 26. Advantageously, the steps (a), (b) and (c) of the recycling process are implemented in a mode of operation, called "out of production", that is to say without preforms 14 are circulated inside the oven 26. is the means 30 for heating are then active or no. Preferably, the heating means 30 are, however, active to effect drying of the cooling air. In such a mode out of production, the air sucked is not - in the absence of preforms 14 - used for cooling the bodies but for cooling the mechanical members, such as the support means of the preforms 14 adapted to rotate them on itself ("spinners"). Thus, step (b) of the recycling process of extracting the filtered air out of the oven 26 is in no way limited to the case where the air is used, while the heating means is active, for cooling at least a portion of the preforms 14 or the only mechanical members of the transport device 28 for said operating mode out of production. Advantageously, the means 54 for extracting the recycling circuit 62 are controlled, preferably in conjunction with the means 32 for supplying the cooling device 34, to establish a circulation of air in a loop between the industrial premises 16 of volume V and the interior volume of the oven 26.

Such an off-production mode of operation is advantageously implemented before the production begins to improve the cleanliness of the ambient air contained in the volume V of the industrial premises 16.

Depending on the factor F, the volume of ambient air filtered by the filtration means 36 before being recycled by the circuit 62 will be more or less important, so after a period of time determined a maximum degree of cleanliness is likely to to be reached before the beginning of the manufacture of the containers 12.

The non-production mode thus advantageously precedes a production mode in which the plant 10 is in operation to manufacture containers 12, preforms 14 being introduced at the inlet E of the furnace 26 for the purpose of their thermal conditioning.

Claims (10)

REVENDICATIONS1. Assembly (5) for the production of containers (12) comprising at least: - a building comprising a closed industrial premises (16) 5 defining a volume (V) of ambient air; an installation (10), implanted in said industrial premises (16), for the manufacture of containers (12) from preforms (14) of thermoplastic material, comprising at least one enclosure (18) of protection intended to isolate a volume interior (10) of the installation (10) relative to the ambient air and comprising at least - a preform thermal conditioning unit (14) arranged in said interior space (20) and consisting of an oven (26). ) having heating means (30) and at least one cooling device (34), said cooling device (34) having air supply means (32) associated with filter means (36) ambient air, are capable of delivering filtered air for the air cooling of at least a portion of the preforms (14) in transit within the furnace (26), and - an extraction system of air associated with the oven (26) which comprises extracting means capable of extracting the cooling air out of the inner volume (20) of the oven (26) and discharging said air after cooling, characterized in that the installation (10) comprises a circuit (62) for recycling cooling air suitable for recycling at least a portion of the filtered air extracted by said extraction means (54) by reintroducing said air into the industrial premises (16). 30 2. An assembly according to claim 1, characterized in that the recycling circuit (62) comprises at least one main conduit (64) whose upstream end is connected to the extraction means (54) and a downstream end of which opens into the industrial premises (16) to reintroduce said filtered air extracted from the oven (26). 3. An assembly according to one of claims 1 or 2, characterized in that the means (54) for extracting the recycling circuit (62) comprise at least one hood (58) which, with a complementary portion of the enclosure (18), is able to confine the interior volume (20) of the oven (26) to isolate it from the ambient air and at least one fan (60) able to extract the filtered air present in the interior volume (20). ) of the oven (26) for recycling said air into the industrial premises (16) via said recycling circuit (62). 4. An assembly according to one of claims 2 or 3, characterized in that the recycling circuit (62) comprises at least one evacuation pipe (56), one end of which is connected to the means (54, 58, 60). extraction and whose other end opens out of the industrial premises (16) and in that the recycling circuit (62) comprises control means (66) which are able to selectively distribute the extracted air in the evacuation conduit (56) and / or in the main conduit (64). 20 5. An assembly according to any one of the preceding claims, characterized in that the recycling circuit (62) comprises at least one control unit (70) able to control the extraction means (54) and the means (32). in such a way that the volume (Ve) of air extracted by the extraction means (54) is greater than the volume (Va) of ambient air drawn by the means (32) for feeding the device (34). ) in the industrial premises (16) volume (V). 6. The assembly as claimed in one of the preceding claims, characterized in that the recycling circuit (62) comprises means (68) for cooling the air which are able to be selectively controlled to regulate the temperature of the air. recycled so that the temperature of said recycled air, intended to be reintroduced into the industrial premises (16), is less than or equal to a set temperature determined to maintain the ambient temperature of the air in the industrial premises (16) in a determined range of temperatures. 7. An assembly according to any one of the preceding claims, characterized in that the means (54) of extraction are capable of establishing a circulation of air loop between the volume (V) of the industrial premises (16) and the volume interior (20) of the furnace (26) with a factor (F) corresponding to the ratio of the volume (Ve) of air extracted out of the oven (26) by the extraction means (54) on the volume (V) of the industrial premises (16) which, for a given unit operating time, is greater than or equal to 1. 8. The assembly of claim 7, characterized in that the extraction means (54) are controlled so as to establish a factor (F) between 2 and 20, preferably between 8 and 12. 9. A method for recycling air in a production assembly comprising a building comprising a closed industrial premises (16) delimiting a volume (V) of ambient air, and an installation (10) located in the room. industrial (16), for the manufacture of containers (12) from preforms (14), the recycling process comprising at least the steps of successively: (a) filtering ambient air to obtain a filtered air suitable for Be used for air cooling at least a portion of the preforms (14) during thermal conditioning in an oven (26) of the plant (10); (b) extracting filtered air from the oven (26); (c) recycling at least a portion of said filtered air extracted from the furnace (26) by reintroducing at least a portion of said air into said industrial premises (16). 10. The method of claim 9, characterized in that the recycling process comprises at least one step of: - controlling the extraction means (54) for establishing a loop air circulation between the volume (V) of the industrial premises (16) and the interior (20) of the oven (26) with a factor (F) corresponding to the ratio of the volume (Ve) of air extracted from the oven (26) by the extraction means (54) on the volume (V) of the industrial premises (16) which, for a given unit operating time, is greater than or equal to 1.