Method for controlling the opening of a flap of an overpressure chamber

Abstract

The invention relates to a control method for a facility (10) for producing containers (12), the facility comprising: - a first protective chamber (14) containing at least one blowing unit (16); - a second containment chamber (18) adjoining the first chamber (14) by a shared partition (22) and containing a filling unit (20); - an opening (24) made in the shared partition (22) for transferring the containers (12); - the flap (26) for shutting off the opening (24); - means (38) for maintaining an overpressure in the second chamber (18), the overpressure having an operational value (P1) higher than a sterilisation maintenance threshold (P2); characterised in that the opening speed (V) of the shut-off flap (26) is controlled so that the overpressure is maintained between the operational value (P1) and the sterilisation maintenance threshold (P2).

Description

Description Title of the invention: METHOD FOR CONTROLLING THE OPENING OF A SHUTTER OF AN ENCLOSURE UNDER OVERPRESSURE Technical field of the invention

[0001] The invention relates to a method for controlling the opening of at least one closure flap in an installation for the production of containers, in particular bottles, comprising at least:

[0002] - a first protective enclosure inside which at least one container blowing unit is arranged;

[0003] - a second containment enclosure adjoining the first enclosure by a common partition which delimits a sterile zone inside which is arranged at least one unit for filling the manufactured containers;

[0004] - at least one opening which is made in said common partition and which is intended to allow the transfer of containers from the blowing unit to the filling unit;

[0005] - the shutter for closing said opening which is controlled between an open position and a fully closed position;

[0006] - means for maintaining an overpressure in the second enclosure relative to the pressure in the first enclosure, the overpressure having an operating value greater than a sterilization maintenance threshold determined in a production mode of the installation. Technical background

[0007] Document WO-2010 / 081759 describes and represents an example of such an installation for the production of containers, in particular bottles.

[0008] The production facility is used for the manufacture of plastic containers, particularly Polyethylene terephthalate (PET).

[0009] Containers are generally manufactured by successively thermally conditioning plastic preforms in an oven, then transforming the preforms into bottles in a blowing unit, the shaping being carried out for example by blowing or stretch-blow molding in a mold, and finally transferring the containers obtained to a filling and capping unit.

[0010] The installation thus comprises, upstream of the filling unit, a manufacturing unit preferably comprising a thermal conditioning oven and a blowing unit.

[0011] Generally, the filling unit and the blowing unit are juxtaposed to to obtain a production facility that is compact and fully carries out the production process of the containers, up to obtaining finished products.

[0012] As explained in document WO-2010 / 081759, the aim in such a production facility is to reduce by all means the risks of contamination of the containers, which containers are moreover likely to be filled with products more or less sensitive to such risks.

[0013] Therefore, it is known to implement various actions there for the sole purpose of controlling and managing the microbiological quality of the production environment, in particular the elimination of pathogenic agents, such as germs, spores, bacteria, etc. which are likely to affect the product contained in the containers, making it unfit for consumption in particular.

[0014] To achieve this, the actions do not exclusively target the sterilization of the containers but also that of the preforms from which they are manufactured as well as that of the installation itself in general.

[0015] The following state-of-the-art documents: WO-2006 / 136498; WO-2008 / 049876; FR-2.915.127, constitute non-limiting examples illustrating such actions and it is advantageous to refer for further details to each of these documents, which are also cited in the preamble to document WO-2010 / 081759.

[0016] Of course, these different examples of actions are likely to be implemented simultaneously in the same installation to drastically reduce the risks of contamination.

[0017] In the production process, the container filling operation is usually recognized as being the most sensitive with regard to contamination risks.

[0018] However, the containers introduced into the filling unit are only one of the main vectors of contamination.

[0019] Indeed, pathogenic agents, when present in the direct environment of the containers, from the air to the organs of the installation units, are particularly likely to contaminate the interior volume of the container.

[0020] This is why, in addition to the sterilization or aseptic treatments directly aimed at the product to be introduced into the container and the container itself, a sterilization operation is also carried out on the filling unit by chemical means, in particular by spraying sterilizing solutions such as sodium hydroxide (NaOH), hydrogen peroxide (H2O2), or peracetic acid (PAA).

[0021] The sterilization operation of the filling unit takes place during a mode of operation, called sterilization, of the installation which precedes and / or follows the implementation of the mode of operation, called production, of the installation in which containers are manufactured.

[0022] In order to implement the sterilization mode of the filling unit, it is necessary to isolate the filling unit from the rest of the installation and in particular from the adjacent blowing unit.

[0023] Indeed, if the components of the filling unit are made of suitable materials, such as 316L stainless steel, to resist the chemical attack of the aforementioned sterilizing solutions which are used for sterilization, this is however not the case for the blowing unit, nor generally for the adjoining transfer device interposed between these units.

[0024] Thus, the sterilizing solutions used for sterilization are likely to cause undesirable chemical attacks, in particular the corrosion of parts of the blowing unit, such as molds, and also parts of the transfer device.

[0025] To reduce the risk of contamination, the blowing unit and the filling unit are each enclosed in an associated enclosure. The two enclosures are adjoined by a common partition with an opening allowing the passage of containers from the blowing unit to the filling unit along a specific path.

[0026] To isolate the filling unit from the blowing unit, the opening can be closed by a door. The opening and closing of this door are generally controlled by a pneumatic cylinder.

[0027] Furthermore, to prevent potentially contaminated air present in the blowing unit enclosure from entering the filling unit enclosure, an operating overpressure is maintained in the filling unit enclosure during the production mode of the installation. For this purpose, the enclosure is supplied with compressed air, the air being filtered and sterilized before being introduced into the enclosure.

[0028] This operating overpressure is for example of the order of 25 Pa. In any case this overpressure is higher than a sterilization maintenance threshold below which the sterilization of the filling chamber is no longer guaranteed, for example air present in the chamber of the blowing unit is likely to enter the chamber of the filling unit. This sterilization maintenance threshold is for example of the order of 18 Pa.

[0029] Furthermore, it is also known to equip the enclosure of the filling unit with means for creating a laminar air flow directed from top to bottom so as to direct any contaminants towards the ground, below the path of the containers.

[0030] It was found that when the door was opened after a sterilization operation, the transient rebalancing of the pressures between the two enclosures produced a very significant drop in the overpressure in the enclosure of the filling unit near the opening. The air present in the filling unit enclosure is then sucked into the blowing unit enclosure. However, the drop in overpressure below the sterilization maintenance threshold does not guarantee that the air present in the filling unit enclosure remains sterile.

[0031] To avoid this drop in overpressure in the filling chamber when the door is opened, it has already been proposed to control the means for maintaining overpressure in such a way as to produce a temporary overpressure during the sterilization operation much higher than the operating overpressure just before the door is opened. Thus, even if the pressure drops in the chamber of the filling unit, it remains at overpressure beyond the sterilization maintenance threshold compared to the chamber of the blowing unit. This temporary overpressure is for example of the order of 80 Pa.

[0032] However, this temporary increase in overpressure generates additional energy expenditure.

[0033] In addition, this requires having means of maintaining the overpressure sized to obtain such overpressure.

[0034] Additionally, opening the door further disrupts the laminar airflow, creating turbulence that may cause any contaminants present in the filling unit to rise. Summary of the invention

[0035] The invention proposes a method for controlling the opening of at least one shutter in an installation for the production of containers, in particular bottles, comprising at least:

[0036] - a first protective enclosure inside which at least one container blowing unit is arranged;

[0037] - a second containment enclosure adjoining the first enclosure by a common partition which delimits a sterile zone inside which is arranged at least one unit for filling the manufactured containers;

[0038] - at least one opening which is made in said common partition and which is intended to allow the transfer of containers from the blowing unit to the filling unit;

[0039] - the shutter for closing said opening which is controlled between an open position and a fully closed position;

[0040] - means for maintaining an overpressure in the second enclosure relative to the pressure of the first enclosure, the overpressure having an operating value greater than a sterilization maintenance threshold determined in a production mode of the installation;

[0041] characterized in that at the start of opening of the shutter, the overpressure is substantially maintained at its operating value, an opening speed of the shutter is regulated so that the overpressure inside the second enclosure remains constantly between the operating value and the sterilization maintenance threshold.

[0042] According to another characteristic of the method carried out according to the teachings of the invention, the opening speed of the shutter is controlled in an open loop according to a predetermined control law.

[0043] According to another characteristic of the method carried out according to the teachings of the invention, the opening speed of the shutter is substantially constant throughout its opening.

[0044] According to another characteristic of the method carried out according to the teachings of the invention, the opening speed of the shutter increases during opening from an initial opening speed to a final opening speed.

[0045] According to another characteristic of the method carried out according to the teachings of the invention, the opening speed of the shutter is controlled by the overpressure measured inside the second enclosure near the opening.

[0046] According to another characteristic of the method carried out according to the teachings of the invention, the means for maintaining the overpressure are controlled so as to re-establish an overpressure greater than an intermediate value between the sterilization maintenance threshold and the operating value.

[0047] According to another characteristic of the method carried out according to the teachings of the invention, the second enclosure comprises means for establishing a laminar air flow directed vertically at least close to the opening.

[0048] According to another characteristic of the method carried out according to the teachings of the invention, the shutter is mounted to slide in the opening.

[0049] The invention also proposes an installation for the production of containers, in particular bottles, for implementing the method according to the teachings of the invention, the installation comprising at least:

[0050] - a first protective enclosure inside which at least one container blowing unit is arranged;

[0051] - a second containment enclosure adjoining the first enclosure by a common partition which delimits a sterile zone inside which is arranged at least one unit for filling the manufactured containers,

[0052] - at least one opening which is made in said common partition and which is intended to allow the transfer of containers from the blowing unit to the filling unit;

[0053] - a shutter for closing said opening which is controlled between an open position and a fully closed position;

[0054] - means for maintaining an overpressure in the second enclosure, the overpressure having an operating value greater than a sterilization maintenance threshold determined during a production mode of the installation;

[0055] characterized in that the movements of the shutter between its open position and its fully closed position are controlled by an electric motor actuator electrically powered via a regulator, such as a variator or an analog card.

[0056] According to another characteristic of the installation produced according to the teachings of the invention, an atmospheric pressure sensor is arranged in the second enclosure near the opening. Brief description of the figures

[0057] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the following appended drawings.

[0058] [Fig.l] is a top view which schematically represents an installation produced according to the teachings of the invention comprising a blowing unit included in a first enclosure and a filling unit included in a second adjoining enclosure.

[0059] [Fig.2] is a perspective view with partial tearing away of the walls of the second enclosure which represents the interior of the second enclosure and a container transfer opening equipped with a shutter in the open position.

[0060] [Fig. 3] is a cross-sectional view along a section plane orthogonal to the dividing wall between the two enclosures and passing through the opening, which represents, in solid lines, the shutter in an open position, and in broken lines, the shutter in the fully closed position.

[0061] [Fig.4] is a diagram which represents the evolution of the opening speed of the shutter as a function of time during a control method according to a first embodiment of the invention.

[0062] [Fig.5] is a diagram similar to that of [Fig.4] which represents the evolution of the opening speed of the shutter as a function of time during a control method according to a variant of the first embodiment of the invention.

[0063] [Fig.6] is a diagram similar to that of [Fig.4] which represents, in solid lines, the evolution of the opening speed of the shutter as a function of time during a control method according to a second embodiment of the invention, and, in broken lines, the variation of the pressure as a function of time in the second enclosure near the opening. Detailed description of the invention

[0064] In the remainder of the description, similar or identical elements will be designated by the same references.

[0065] In the description, expressions such as "upstream" and "downstream", "upper" and "lower", "inner" and "outer", "front" and "rear" and the longitudinal, vertical and transverse orientations will be used without limitation with reference to the trihedrons (L, V, T) shown in the figures and / or to the definitions given in the description.

[0066] [Fig.l] shows an example of an embodiment of an installation 10 for the production of containers 12, in particular, but not exclusively, bottles.

[0067] As partially shown in [Fig.l], the installation 10 comprises at least one first protective enclosure 14 which delimits a first zone ZI inside which is arranged at least one unit 16 for blowing containers 12.

[0068] Preferably, the blowing unit 16 is capable of manufacturing containers 12 by blowing or by stretch-blow molding from preforms (not shown) which are previously thermally conditioned in an oven (not shown), in particular by heating using infrared radiation lamps.

[0069] The blowing unit 16 comprises a carousel 17 at the radial periphery of which molds 19 are circumferentially arranged in which the heated preforms are transformed into containers 12 by blowing or by stretch-blow molding depending on the applications.

[0070] The installation 10 comprises a second containment enclosure 18 which delimits a second sterile zone Z2, inside which is arranged at least one unit 20 for filling the containers 12 manufactured by the blowing unit 16.

[0071] The second containment enclosure 18 is adjacent to the first adjoining enclosure 14 by a common partition 22.

[0072] Each of the enclosures 14 and 18 consists of a set of vertical walls which are respectively closed above and below, for example by a wall forming a ceiling 21 and by the floor respectively.

[0073] Preferably, at least one of the vertical walls of the enclosures 14 and 18 comprises at least one door (not shown) in order to allow them to be crossed, in particular by an operator, and access to the interior of the installation 10.

[0074] The installation 10 comprises at least one opening 24 which is made in said partition 22 common to the first and second enclosures 14 and 18. The opening 24 visible in [Fig.2] is intended to allow the transfer of the containers 12 from the blowing unit 16 to the filling unit 20.

[0075] Advantageously, the installation 10 comprises at least one shutter 26 for closing said opening 24 which is capable of being moved between at least one open position and one completely closed position.

[0076] The installation 10 here comprises a single shutter 26.

[0077] Alternatively, the installation 10 comprises at least two shutters which cooperate to close the opening.

[0078] The open position corresponds to the position in which the shutter 26 allows the transfer of the containers 12 through the opening 24, as shown in [Fig. 2]. This open position is occupied when the installation 10 is in an operating mode, called production mode.

[0079] The fully closed position corresponds to the position in which the shutter 26 completely closes the opening 24 by isolating the second enclosure 18 from the first enclosure 14.

[0080] The fully closed position is in particular intended to allow a sterilization operation of the filling unit 20 to be carried out at least in the second enclosure 18, when the installation 10 is in another operating mode, called sterilization mode.

[0081] Advantageously, the closure flap 26 ensures, in said fully closed position, a hermetic closure of the opening 24 capable of isolating the second enclosure 18 comprising the filling unit 20 from the first enclosure 14 comprising the unit 16 for blowing the containers 12.

[0082] The shutter 26 is here mounted to slide between said open and fully closed positions by means of two slides 27. The shutter 26 is here mounted to slide vertically. The shutter 26 opens here by sliding upwards.

[0083] In a variant of the invention not shown, the shutter 26 can open by sliding downwards.

[0084] According to another variant of the invention, not shown, the shutter 26 is mounted to slide in a horizontal direction.

[0085] The slides 27 of the shutter 26 are integral with the common partition 22 and are arranged respectively to the right and left of the opening 24 which here has a generally rectangular shape more particularly visible in [Fig.2].

[0086] Preferably, the installation 10 comprises actuating means 28 intended to control the movement of the closure flap 26 between the open position corresponding to the production mode and the completely closed position corresponding to the sterilization mode.

[0087] These are actuating means whose speed can be controlled. The actuating means are here formed by an actuator 28 with an electric motor. The electric motor is here electrically powered via a regulator 31, such as a variator or an analog card, to allow the speed of the actuator 28 to be varied.

[0088] The regulator 31 is itself controlled by an electronic control unit 33.

[0089] The sterilization operation of the filling unit 20 is carried out chemically by spraying sterilizing solutions, such as sodium hydroxide (NaOH) or hydrogen peroxide (H2O2), inside the second enclosure 18.

[0090] The spraying of such sterilizing solutions to sterilize the second enclosure 18 is made possible in particular by the use of stainless steel or other compatible materials to produce parts such as those of the filling unit 20.

[0091] The installation 10 comprises a transfer device 29 for ensuring the transfer of the containers 12 between the blowing unit 16 and the filling unit 20.

[0092] The transfer device 29 comprises at least one transfer wheel 30 which is adjacent to the opening 24 provided in the common partition 22 and which is intended to transfer, in production mode, the containers 12 through said opening 24.

[0093] Preferably, the transfer device 29 comprises, in addition to the transfer wheel 30, two other transfer wheels 32 and 34 respectively arranged upstream and downstream of the wheel 30.

[0094] The different wheels 30, 32 and 34 of the transfer device 29 are arranged relative to each other so as to each have a portion in the form of an arc of a circle tangent to the portion of the adjacent wheel in order to determine a zone in which the transfer of the containers 12 from one to the other takes place.

[0095] The first transfer wheel 32 is arranged between the inlet of the transfer wheel 30 and an outlet zone of the carousel 17 of the blowing unit 16 in which the molds are controlled to open to allow the extraction of the containers 12 manufactured using the associated blowing or stretch-blow molding means.

[0096] The first transfer wheel 32 is intended to ensure the extraction of the containers 12 manufactured in the molds and their transfer downstream, for example by means of transfer arms provided at their free end with gripping means, such as clamps.

[0097] The second transfer wheel 34 is arranged, downstream, between the outlet of the transfer wheel 30 and another carousel 35 which the filling unit 20 comprises, the filling stations of the containers 12 being distributed circumferentially in a regular manner around said carousel.

[0098] Advantageously, the installation 10 is designed so as to reduce or eliminate the various risks of contamination.

[0099] The transfer wheel 30 comprises at least one part which is mounted movably between at least a first transfer position and a second retracted position.

[0100] The first transfer position is occupied when the installation 10 is in production mode and the second retracted position when the installation 10 is in sterilization mode.

[0101] The transfer wheel 30 comprises at least holding means 36 which extend partly through the opening 24 and, in production mode, cooperate with the containers 12 to transfer them.

[0102] The holding means 36 comprise, for example, notches intended to cooperate with a part of the container.

[0103] The transfer wheel 30 is mounted to move between at least:

[0104] - the first transfer position in which the means 36 for holding the wheel 30 extend through the opening 24 to ensure the transfer of the containers 12 during operation in production mode of the installation 10, and

[0105] - the second retracted position in which at least the wheel 30 is moved to allow the opening 24 to be closed by the associated shutter 26 for the purpose of operating the installation 10 in sterilization mode.

[0106] Advantageously, the transfer wheel 30 is moved automatically by means of an actuator (not shown).

[0107] Preferably, the transfer wheel 30 of the installation 10 is in this first embodiment of a design similar to that described in document WO-2010 / 081759.

[0108] As explained in the preamble, the aim of the present invention is to reduce microbiological risks within a container production facility 10, by combating the various risks of contamination of the containers by pathogenic agents and this in order to further improve the food safety of the containers.

[0109] For this purpose, the installation 10 comprises means 38 for maintaining an overpressure by blowing in filtered air “Al” to establish an overpressure inside the second enclosure 18 relative to the pressure of the first enclosure 14.

[0110] Such means 38 for maintaining an overpressure are well known and will not be described in more detail below. This involves, for example, a ventilation device equipped with filters capable of obtaining air suitable for a sterilized enclosure.

[0111] In the remainder of the description and in the claims, an overpressure is defined as being the difference between the pressure prevailing in the second enclosure 18 and the pressure prevailing in the first enclosure 14. The value of the overpressure is always positive so as to prevent contaminated air from entering the interior of the second enclosure 18. This overpressure thus makes it possible to limit the risks of contamination.

[0112] When the shutter 26 is in its open position, the overpressure having an operating “PI” value greater than a determined sterilization maintenance threshold “P2” when the installation 10 operates in production mode.

[0113] By way of non-limiting examples, the operating value “PI” is approximately 25 Pa, while the sterilization maintenance threshold “P2” is approximately 18 Pa. Preferably, to avoid unnecessary energy expenditure, the difference between the operating value “PI” and the sterilization maintenance threshold “P2” is here less than 10 Pa.

[0114] Furthermore, to obtain optimal sterilization of the second enclosure 18 during the production mode, means 40 are also provided for establishing a flow “A2” of laminar air directed vertically at least near the opening 24.

[0115] The means 40 here comprise a filtered air ventilation device 42 which supplies nozzles 44 via suitable pipes.

[0116] The laminar air flow “A2” is here directed from top to bottom to carry any contaminants towards the ground. For this purpose, the nozzles 44 are arranged on the ceiling 21 to emit the laminar air flow “A2” vertically downwards.

[0117] To avoid the creation of turbulence when the flow “A2” of laminar air reaches the ground, an air extraction device 46 is provided which sucks in the air via orifices arranged at the ground level of the second enclosure 18.

[0118] During a sterilization operation of the filling unit 20, the installation 10 switches from production mode to sterilization mode by retracting the transfer wheel 30 and completely closing the shutter 26.

[0119] At the end of this sterilization operation, the shutter 26 must be opened again. This is to ensure that the interior of the second enclosure 18, just sterilized, is not exposed to contaminants. This involves, on the one hand, preventing the overpressure in the second enclosure 18 from falling below the sterilization maintenance threshold “P2”, but also, on the other hand, preventing the laminar air flow “A2” from becoming turbulent, thus causing mixing of any residual contaminants entrained towards the bottom of the second enclosure 18.

[0120] The invention proposes that at the start of the opening of the closure flap 26, the overpressure is maintained at its operating value “PI”, here at 25 Pa. To avoid an air intake when the closure flap 26 is opened, its opening speed during its movement from its fully closed position to its open position is regulated so that the overpressure inside the second sterile zone remains constantly greater than or equal to the sterilization maintenance threshold “P2” without being significantly greater than the operating value “PI”.

[0121] By avoiding excessive fluctuations in pressure inside the second enclosure 18, it is advantageous to avoid disturbing the flow of the air flow “A2”. laminar.

[0122] According to a first embodiment of the invention, the opening speed of the shutter 26 is controlled in an open loop according to a predetermined control law. This control law is for example recorded or parameterized in the electronic control unit. This control law is for example determined by testing during the assembly of the installation 10 or by simulation, by testing or estimating the overpressure inside the second enclosure 18 near the opening 24.

[0123] The opening speed “V” of the shutter 26 is for example substantially constant throughout its opening, as shown in the graph of [Fig. 4]. In this graph, the opening of the shutter 26 begins at time “tl”, corresponding to the fully closed position, and ends at time “t2”, corresponding to the open position. Apart from the start ramp and the end ramp which correspond to the intrinsic transition acceleration of the actuator 28 at the start and end of the opening, the sliding speed “V0” of the shutter 26 is constant throughout the opening. The opening speed “V0” is for example 10 mm / s.

[0124] This opening speed “V0” is for example determined by testing during the assembly of the installation 10 or by simulation.

[0125] As a variant of this first embodiment which is shown in [Fig.5], the speed “V” of opening of the shutter 26 varies very significantly during its opening.

[0126] For example, the door opening speed increases during opening from an initial opening speed “Vlmin” to a final opening speed “Vlmax”.

[0127] The initial speed “V 1min” is for example of the order of a few millimeters per second while the final speed “Vlmax” is much higher than 10 mm / s. This is for example the maximum speed that can be obtained safely by the actuator 28.

[0128] In the example shown, the speed “V Imax” has a plateau for the end of the opening of the shutter 26.

[0129] According to a second embodiment of the invention, the speed “V” of opening of the shutter 26 is controlled by the overpressure “P” measured inside the second enclosure 18 near the opening 24. For this purpose, an atmospheric pressure sensor 48 is arranged in the second enclosure 18 near the opening 24. By way of non-limiting example, the pressure sensor 48 is here arranged against the common partition 22 below the opening 24.

[0130] The pressure sensor 48 is capable of communicating the pressure measurements to the electronic control unit 33 to enable it to regulate the opening speed “V” as a function of these pressure measurements.

[0131] The electronic control unit 33 calculates the overpressure “P” by subtracting from the measurement of the pressure sensor 48 the pressure prevailing in the first enclosure 14, this pressure being for example measured, estimated or predefined.

[0132] According to an exemplary embodiment of this second embodiment shown in [Fig. 6], when the shutter 26 begins to open, the opening speed “V” increases progressively. When a drop in overpressure “P” near the opening 24 is detected, for example when the measured overpressure “P” is less than a slowdown value “P” between the sterilization maintenance threshold “P2” and the operating value “PI” (as shown in broken lines in [Fig. 6]), the opening speed “V” (shown in solid lines in [Fig. 6]) is reduced by the electronic control unit 33 until the overpressure “P” starts to increase again. When the overpressure “P” increases again beyond an acceleration overpressure “P4” between the slowdown overpressure “P3” and the operating value “PI”, the opening speed “V” increases again.

[0133] During opening, the speed “V” can thus vary between zero and the maximum speed capable of being obtained safely by the actuator 28.

[0134] This second embodiment thus makes it possible to reduce the opening time compared to the first embodiment by taking into account the overpressure “P” measured in the second enclosure 18.

[0135] It is possible to further reduce the opening time by combining the regulation of the opening speed “V” of the shutter 26 with the control of the means 38 for maintaining the overpressure. Indeed, when a measured overpressure is lower than the slowing overpressure “P3”, said means 38 are controlled so as to re-establish an overpressure approaching the operating value “PI” by temporarily increasing the pressure of the blown air. Thus, the overpressure returns to the acceleration value “P4” more quickly, which makes it possible to reduce the opening time of the shutter 26.

[0136] The invention makes it possible to reduce the energy consumption of the installation 10 by not placing excessive strain on the means 38 for maintaining the overpressure.

[0137] Furthermore, the invention thus makes it possible to guarantee that the overpressure in the second enclosure 18 remains higher than the sterilization maintenance threshold “P2” without, however, disturbing the flow of the laminar air flow “A2”.

Claims

Claims

1. Method for controlling the opening of at least one shutter (26) in an installation (10) for the production of containers (12), in particular bottles, comprising at least: - a first protective enclosure (14) inside which at least one container blowing unit (16) is arranged; - a second containment enclosure (18) adjacent to the first enclosure (14) by a common partition (22) which delimits a sterile zone (Z2) inside which is arranged at least one unit (20) for filling the manufactured containers (12); - at least one opening (24) which is made in said common partition (22) and which is intended to allow the transfer of the containers (12) from the blowing unit (16) to the filling unit (20); - the shutter (26) for closing said opening (24) which is controlled between an open position and a completely closed position; - means (38) for maintaining an overpressure in the second enclosure (18) relative to the pressure of the first enclosure (14), the overpressure having an operating value (PI) greater than a sterilization maintenance threshold (P2) determined in a production mode of the installation (10); characterized in that at the start of the opening of the closure flap (26), the overpressure is substantially maintained at its operating value (PI), a speed (V) of opening of the closure flap (26) is regulated so that the overpressure inside the second enclosure (18) remains constantly between the operating value (PI) and the sterilization maintenance threshold (P2).

2. Method according to the preceding claim, characterized in that the speed (V) of opening of the shutter (26) is controlled in an open loop according to a predetermined control law.

3. Method according to the preceding claim, characterized in that the speed (V) of opening of the shutter (26) is substantially constant throughout its opening.

4. Method according to claim 2, characterized in that the speed (V) of opening of the shutter (26) increases during opening from an initial opening speed (Vlmin) to a final opening speed (Vlmax).

5. Method according to claim 1, characterized in that the speed (V) opening of the shutter (26) is controlled by the overpressure (P) measured inside the second enclosure (18) near the opening (24).

6. Method according to any one of claims 2 to 5, characterized in that the means (38) for maintaining the overpressure (P) are controlled so as to reestablish an overpressure greater than an intermediate value (P4) between the sterilization maintenance threshold (P2) and the operating value (PI).

7. Method according to any one of the preceding claims, characterized in that the second enclosure (18) comprises means (40) for establishing a flow (A2) of laminar air directed vertically at least close to the opening (24).

8. Method according to any one of the preceding claims, characterized in that the shutter (26) is slidably mounted in the opening (24).

9. Installation (10) for the production of containers, in particular bottles, for implementing the method according to any one of the preceding claims, the installation comprising at least: - a first protective enclosure (14) inside which at least one container blowing unit (16) is arranged; - a second containment enclosure (18) adjoining the first enclosure (14) by a common partition (22) which delimits a sterile zone (Z2) inside which is arranged at least one unit (20) for filling the manufactured containers (12), - at least one opening (24) which is made in said common partition (22) and which is intended to allow the transfer of the containers (12) from the blowing unit (16) to the filling unit (20); - a shutter (26) for closing said opening (24) which is controlled between an open position and a completely closed position; - means (38) for maintaining an overpressure in the second enclosure (18), the overpressure having an operating value (PI) greater than a sterilization maintenance threshold (P2) determined during a production mode of the installation (10); characterized in that the movements of the shutter (26) between its open position and its fully closed position are controlled by an actuator (28) with an electric motor electrically powered via a regulator (31), such as a variator or an analog card.

10. Installation (10) according to the preceding claim, characterized in that an atmospheric pressure sensor (48) is arranged in the second enclosure (18) near the opening (24).

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