METHOD AND DEVICE FOR DIAGNOSING A ROTARY DISTRIBUTOR

Abstract

The invention relates to a method for diagnosing the condition of a rotating distributor (60) for a hollow body processing unit (22) comprising a rotating carousel (32), the rotating distributor (60) comprising: - a rotor (64) mounted fixed relative to the carousel (32); - a stator (62), the rotor (64) being capable of applying a stator torque (Cs) to the stator (62), the stator (62) being prevented from rotating by means of an anti-torque device (86); - at least one fluidic or electrical circuit (70A, 70B) enabling communication between a fixed connector (66A, 66B) of the stator (62) and a rotating connector of the rotor (64); characterized in that the method comprises a first step (E1) of verifying that the stator torque (Cs) is less than a maximum permissible value (Cmax) by means of a device (92). Couple monitoring. Figure for the abbreviation: Figure 2

Description

Title of the invention: METHOD AND DEVICE FOR DIAGNOSING A ROTARY DISTRIBUTOR Technical field of the invention

[0001] The invention relates to a method for diagnosing the condition of a rotary distributor for a thermoplastic hollow body processing unit comprising a carousel mounted to rotate on a fixed frame around a central axis, the rotary distributor comprising:

[0002] - a rotor mounted fixed relative to the carousel;

[0003] - a stator on which the rotor is mounted to rotate coaxially around the central axis, the rotor being capable of applying to the stator a rotational torque in a first direction, called stator torque, during the rotation of the carousel, the stator being immobilized in rotation relative to the frame around the axis of rotation by means of an anti-torque device;

[0004] - at least one fluidic or electrical circuit allowing communication to at least one first connector, called fixed connector, of the stator, with at least one second connector, called rotating connector, of the rotor during the rotation of the rotor relative to the stator. Technical background

[0005] The invention is intended to be implemented in a manufacturing plant for containers made of thermoplastic material, particularly polyethylene terephthalate (PET), by forming, notably by blow molding or stretch blow molding, preforms. Such a manufacturing plant makes it possible to produce containers in very large series at very high production rates.

[0006] Preforms are generally manufactured by injection molding at one location and then blow-molded into the final shape of the container at a second location on the manufacturing plant. This technology allows the blow-molding operation to be carried out as close as possible to the bottling site, while the injection molding operation can be performed anywhere. Indeed, it is relatively easy and inexpensive to transport small preforms, whereas transporting blow-molded containers is economically unviable due to their very large size.

[0007] To enable its forming, the body of the preform is heated above a glass transition temperature, making the body wall malleable by significantly reducing its elastic limit. Conversely, the neck is maintained at a temperature below the glass transition temperature to avoid its deformation. For this purpose, the manufacturing installation includes a thermal conditioning unit which allows the body of the preforms to be heated to the temperature required to carry out the forming step.

[0008] The heated preforms are then conveyed to a forming unit of the manufacturing plant equipped with forming stations. The hot preforms are automatically deposited into mold cavities at each forming station by gripping devices such as grippers. Then, a pressurized forming fluid is injected into the preforms to press the preform wall against the cavity walls, thus shaping the preform into the final container. This forming operation is generally accompanied by a stretching operation, which involves inserting a stretching rod into the preform body to axially stretch the preform wall.

[0009] When the injected fluid is a gas, such as air, this is generally referred to as a blowing operation. The gas is applied at a very high pressure, for example, on the order of 40 bar.

[0010] The installation comprises at least one processing unit including a carousel with a plurality of hollow body processing stations on its periphery. The forming unit constitutes such a processing unit.

[0011] To enable the production of containers in large series, the forming station thus comprises several forming stations mounted on a rotating carousel.

[0012] The processing stations of these processing units, particularly the forming stations, must be able to be supplied with various fluids and / or electricity to enable the processing of hollow bodies. Examples of fluids include, but are not limited to:

[0013] - a pressurized forming fluid, such as air, to enable the forming of containers;

[0014] - a heat transfer fluid to allow the thermal regulation of hollow bodies or of certain components of the processing units; or

[0015] - a dust-removing fluid for cleaning preforms before they are formed; or

[0016] - a preform decontamination fluid, such as hydrogen peroxide or peracetic acid.

[0017] To be able to convey one or more of these fluids and / or electricity to the processing stations mounted on the carousel, it is known to equip the processing unit with a rotary valve, sometimes called a "rotary joint". Such a rotary valve comprises a rotor that rotates in conjunction with the carousel and a stator that is fixed relative to the frame on which the rotating carousel is mounted. The rotary valve comprises at least one fluid or electrical circuit allowing connection of at least one fixed connector arranged on the stator with at least one rotating connector arranged on the rotor. Thus, it is possible to connect each fixed connector with a fluidic conduit or an electrical cable fixed relative to the frame and each rotating connector with a fluidic conduit or an electrical cable rotating jointly with the carousel.

[0018] The rotary distributor includes seals which are interposed between the rotor and the stator to ensure that the fluids circulating in the fluidic circuit do not leak between the stator and the rotor or to ensure the sealing of the electrical circuit.

[0019] In addition to their sealing function, these sealing elements must have a sufficiently low coefficient of friction to allow the rotor to rotate relative to the stator while minimizing friction. However, the friction is still sufficiently intense for the rotor to apply a torque to the stator, known as stator torque, which tends to cause the stator to rotate with the rotor.

[0020] To prevent the stator from rotating relative to the frame, an anti-torque device is provided which has the function of immobilizing the stator in rotation relative to the frame.

[0021] In the event of a seizing of the rotary distributor, the stator torque may exceed the resistance of the anti-torque device, causing the latter to fail. The stator is then driven into rotation, resulting in the tearing of fixed conduits and / or cables and other collateral damage.

[0022] Furthermore, it has also been observed that, conversely, when the linings become too worn, the stator torque decreases sharply. However, this decrease in stator torque is accompanied by a loss of sealing between the stator and the rotor.

[0023] To avoid this problem, very frequent verification operations are currently being carried out which must be performed out of production.

[0024] There is therefore a need to reduce the frequency of maintenance operations of the rotary distributor and to reduce the duration and frequency of periods of downtime of the processing unit.

[0025] In addition, it is preferable to be able to anticipate future degradation of the rotary distributor and to warn an operator of the need for maintenance before the rotary distributor is too damaged. Summary of the invention

[0026] The invention proposes a method for diagnosing the condition of a rotary distributor for a thermoplastic hollow body processing unit comprising a carousel mounted to rotate on a fixed frame around a central axis, the rotary distributor comprising: - a rotor mounted fixed relative to the carousel; - a stator on which the rotor is mounted to rotate coaxially around the central axis, the rotor being capable of applying a rotational torque to the stator in the first direction, called stator torque, during the rotation of the carousel, the stator being immobilized in rotation relative to the frame around the axis of rotation by means of an anti-torque device; - at least one fluidic or electrical circuit allowing communication between at least one first connector, called the fixed connector, of the stator, with at least one second connector, called the rotating connector, of the rotor during the rotation of the rotor relative to the stator; characterized in that the method includes a first step of verifying that the stator torque is less than a maximum permissible value by means of a torque monitoring device.

[0027] According to another feature of the method carried out according to the teachings of the invention, the torque monitoring device includes a monitoring element calibrated to allow a pivoting of the stator in said first direction relative to the frame when the stator torque exceeds the maximum permissible value.

[0028] According to another feature of the method carried out according to the teachings of the invention, the torque monitoring device includes a motion detection switch actuated when the stator pivots in the first direction.

[0029] According to another feature of the method carried out according to the teachings of the invention, the torque monitoring device includes a sensor which is capable of measuring a representative value of the stator torque, the first verification step comprising a first sub-step of measuring the stator torque and a second sub-step of comparing the measurement with the maximum permissible value.

[0030] According to another feature of the method carried out according to the teachings of the invention, it includes a second step of verifying that the stator torque is greater than a minimum permissible value by means of said torque monitoring device.

[0031] According to another feature of the method carried out according to the teachings of the invention, the torque monitoring device includes a sensor which is capable of measuring the value of the stator torque, the second verification step comprising a first sub-step of measuring the torque and a second sub-step of comparing the measurement with the minimum permissible value.

[0032] According to another feature of the method carried out according to the teachings of the invention, the same sensor is used during the first verification step and during the second verification step.

[0033] The invention also relates to a hollow body processing unit made of thermoplastic material comprising a carousel mounted rotating on a fixed frame around a central axis, the processing unit comprising a rotating distributor comprising: - a rotor mounted fixed relative to the carousel; - a stator on which the rotor is mounted to rotate coaxially around the central axis, the rotor being capable of applying a rotational torque, called stator torque, to the stator during the rotation of the carousel, the stator being immobilized in rotation relative to the frame around the axis of rotation by means of an anti-torque device; - at least one fluidic or electrical circuit allowing communication between at least one first connector, called the fixed connector, of the stator, with at least one second connector, called the rotating connector, of the rotor during the rotation of the rotor relative to the stator; characterized in that the stator torque is transmitted to the frame via a stator torque monitoring device.

[0034] According to another feature of the processing unit made according to the teachings of the invention, the stator torque monitoring device is a force sensor comprising a strain gauge.

[0035] According to another feature of the processing unit made according to the teachings of the invention, the stator torque monitoring device includes a torque limiter calibrated to the maximum permissible value.

[0036] According to another feature of the processing unit made according to the teachings of the invention, the monitoring device is an element forming a mechanical fuse calibrated to the maximum permissible value.

[0037] According to another feature of the processing unit made according to the teachings of the invention, the monitoring element is part of a stator torque monitoring device.

[0038] According to another feature of the processing unit made according to the teachings of the invention, said processing unit is a preform forming unit. Brief description of the figures

[0039] Other features and advantages of the invention will become apparent during the reading of the detailed description which follows, for the understanding of which reference should be made to the attached drawings.

[0040] Fig. 1 is a schematic top view which represents a hollow body processing unit according to the teachings of the invention.

[0041] Fig.2 is a cross-sectional view through the axis "ZI" of Fig.1 representing a treatment station equipping the treatment unit and a rotary fluidic distributor arranged coaxially to a carousel of the treatment unit to supply a heat exchanger with heat transfer fluid.

[0042] Fig. 3 is a perspective view of the rotary distributor of Fig. 2.

[0043] Fig. 4 is an axial cross-sectional view of the rotary distributor of Fig. 3.

[0044] Fig. 5 is a schematic view representing the rotary distributor equipped with an anti-torque device having a stator torque monitoring device according to a first embodiment of the invention.

[0045] The [Fig.6] is a block diagram which represents a method for diagnosing the condition of the rotary distributor of the [Fig.5] according to a first embodiment of the invention.

[0046] Fig. 7 is a schematic view representing the rotary distributor equipped with an anti-torque device having a stator torque monitoring device according to a second embodiment of the invention.

[0047] Fig. 8 is a top view of the monitoring device of Fig. 7.

[0048] The [Fig.9] is a block diagram which represents a method for diagnosing the condition of the rotary distributor of the [Fig.7] according to a second embodiment of the invention.

[0049] Fig. 10 is a view similar to that of Fig. 4, which represents an electric rotary distributor to which the method and the torque monitoring device are likely to be applied. Detailed description of the invention

[0050] In the following description, elements having an identical structure or analogous functions will be designated by the same reference.

[0051] In the remainder of this description, a vertical orientation parallel to a central axis "Zl" of a carousel 32 and directed from bottom to top along the arrow "V" in the figures will be adopted, without limitation. Radial orientations directed radially outwards from the central axis "Zl" of the carousel 32, and tangential orientations directed orthogonally to the radial and axial orientations will also be adopted. The term "circumferential" will be used to designate a displacement or element extending in an arc of a circle centered on the central axis "Zl" of the carousel 32.

[0052] Figure 1 shows a processing unit 20 for a hollow body 22 made of thermoplastic material comprising a carousel 32. This is shown here as a non-limiting example of a forming unit.

[0053] Alternatively, the application is applicable to any other processing unit comprising a carousel equipped with treatment stations and requiring fluid circulation from a fixed circuit to a circuit mounted on the carousel. This could, for example, be a forming unit, a dust removal unit, or a decontamination unit.

[0054] The processing unit is part of a container manufacturing installation by forming a preform from thermoplastic material.

[0055] When it begins to deform, the preform becomes an "intermediate container" before reaching its final form as a "final container".

[0056] In the rest of the description and in the claims, the term "hollow body 22" will be used to refer indifferently to a preform, an intermediate container or a finished container.

[0057] Such an installation comprises at least one thermal conditioning unit and one forming unit.

[0058] Figure 2 shows a hollow body 22 in its preform state. It is made of thermoplastic material, here polyethylene terephthalate (PET). It has a substantially axisymmetric shape around a principal vertical axis "Z0".

[0059] As shown in [Fig. 2], it has a cylindrical body 24 with a tubular wall, closed at its lower end by a bottom 26, and which is extended at its upper end by a neck 28, also tubular and open vertically upwards. An internal face 29 of the wall delimits the interior of the hollow body 22 in the preform state. The neck 28 is generally injected so as to already possess its final shape, while the body 24 of the hollow body 22 in the preform state is intended to undergo relatively significant deformation to form the final container in a subsequent forming step.

[0060] The neck 28 of the hollow body 22 also includes an annular collar 30 that projects radially. The collar 30 is arranged here at the junction between the base of the neck 28 and the body 24.

[0061] The processing unit 20 comprises a carousel 32 mounted to rotate about a central vertical axis "Zl" on a fixed frame 34, symbolically represented in [Fig.2]. The frame 34 is fixed relative to the ground on which the processing unit 20 rests.

[0062] The carousel 32 is more particularly driven in continuous rotation, here in a clockwise direction as indicated by arrow F in [Fig.1], by a vertical shaft 36 with central axis "Z1", for example by means of an electric motor not shown.

[0063] The carousel 32 includes processing stations 38 intended to receive a hollow body 22 in order to drive the hollow bodies 22 in a line along a common arc-shaped trajectory centered on the central axis "Zl".

[0064] Each processing station 38 includes at least one retaining organ 40 for a hollow body 22. The retaining organ 40 allows the hollow body 22 to be moved along its trajectory.

[0065] In the case where the processing unit 20 is a forming unit, the holding member 40 is formed by a mold which receives a hollow body 22.

[0066] Alternatively, the retaining elements are formed by notches or clips arranged at the periphery of the carousel 32.

[0067] Each support organ 40 here supports the hollow body 22 by its collar 30.

[0068] In an unrepresented variant of the invention, when the retaining members are formed by clamps, the latter grasp each hollow body 22 just above or just below their collar 30.

[0069] The processing unit 20 is designed to allow the transport and processing of a large flow of hollow bodies 22, for example on the order of 60000 hollow bodies 22 per hour.

[0070] As shown in [Fig. 1], the hollow bodies 22 are conveyed to an inlet 44 of the processing unit 20 by an inlet wheel 46, schematically represented by a circle in [Fig. 1]. After processing, here after forming, the hollow bodies 22 are transferred to an outlet wheel 48, schematically represented by a circle in [Fig. 1], at an outlet 50.

[0071] The input and output wheels 46, 48 are, for example, gripper wheels. Between the input 44 and the output 50, the trajectory of the hollow bodies 22 extends here over an angular sector greater than 180°, for example on the order of 300°.

[0072] The carousel 32 is equipped with several processing stations 38 which allow the hollow bodies 22 to be processed, in this case formed, during their transport from the inlet 44 to the outlet 50. Each processing station 38 is mounted on the carousel 32, that is to say, each processing station 38 is driven in rotation around the central axis "Zl" fixed to the carousel 32.

[0073] In this non-limiting example, concerning a forming unit, each processing station 38 comprises a mold, forming the holding element 40, and a nozzle 54 equipped to form the hollow bodies 22, from the preform stage to the final container stage, by blow molding or stretch-blowing. The nozzle 54 here comprises a vertically mounted slidable elongation rod 55 to stretch the body 24 of the hollow body 22 at the beginning of the forming process.

[0074] As shown in Figures 2 and 3, each treatment station 38 comprises the associated blow nozzle 54 mounted on the carousel 32. Each blow nozzle 54 is arranged vertically in correspondence with the associated retaining member 40, formed here by a mold. Thus, the carousel 32 has as many blow nozzles 54 as retaining members 40.

[0075] In such a processing unit 20, the processing stations 38, which are driven in rotation with the carousel 32, must be able to exchange at least one fluid with at least one external fluidic circuit, called fixed circuit 56, which is fixed relative to the frame 34.

[0076] Generally, said fluid is a fluid that participates directly or indirectly in the treatment of hollow bodies. At least one fluidic circuit rotating jointly with the carousel 32, referred to as the rotating circuit 58, must be connected with the circuit 56 fixed relative to the frame 34.

[0077] By way of non-limiting example of such fluids, when the processing unit 20 is a molding unit, the molds forming the holding elements 40 must be maintained at an operating temperature. To regulate their temperature, it is known to circulate a heat transfer fluid in a heat exchanger contained in each mold, which forms one of the rotating circuits 58. This is, for example, a heat transfer fluid. Each processing station 38 is thus equipped with at least one associated rotating circuit 58.

[0078] As this is a heat transfer fluid, the fixed circuit 56 is formed by a cooling circuit which includes a heat transfer fluid inlet pipe 56A and a heat transfer fluid outlet pipe 56B.

[0079] Alternatively, it may also be a pressurized fluid, such as air, which is used for the pneumatic control of valves or other accessories of the processing station.

[0080] When the processing unit is a dust collection unit, the fluid can be pressurized dust collection air.

[0081] Alternatively, when the treatment unit is a decontamination unit for the inside of hollow bodies, the fluid is formed by a sterilizing gas. This is, for example, a gas containing a powerful oxidizing agent such as hydrogen peroxide and / or peracetic acid.

[0082] The fixed circuit 56 is fixed relative to the ground. To allow the fluid to be conveyed to each rotating circuit 58, the treatment unit 20 includes a rotating distributor 60.

[0083] As shown in Figures 3 and 4, the rotating distributor 60 mainly comprises a stator 62 and a rotor 64.

[0084] The rotor 64 is rotatably mounted on the stator 62 around a main axis "Z2".

[0085] As shown in [Fig. 4], bearings 65 for guiding the rotation of the rotor 64 are radially interposed between the rotor 64 and the stator 62. The rotating distributor 60 here comprises two guide bearings 65 arranged at each of its vertical ends. These are rolling bearings 65. In an alternative design of the invention, not shown, they are plain bearings.

[0086] In the embodiment shown in the figures, the stator 62 is arranged inside the rotor 64. For this purpose, the stator 62 has a generally cylindrical shape and the external rotor 64 has a sleeve shape with a vertical axis into which the stator 62 is fitted.

[0087] In an unrepresented variant of the invention, by mechanical inversion, the rotor 64 is arranged inside the stator 62.

[0088] The stator 62 and the rotor 64 are here axially connected, so that the stator 62 is supported by the rotor 64 when the main axis "Z2" of the rotating distributor 60 is vertical.

[0089] The rotor 64 is fixedly mounted on the carousel 32 such that the main axis "Z2" of the rotating distributor 60 is coaxial with the central axis "ZI" of the carousel. More specifically, the rotor 64 is fixed to the carousel 32 such that the entire weight of the rotating distributor 60 is supported by the carousel 32.

[0090] To allow connection of at least one fixed circuit 56 to the rotating distributor 60, the stator 62 includes at least one first connector, referred to as the fixed connector 66A, 66B. In the example shown in the figures, the stator 62 includes two fixed connectors 66A, 66B, one of which is connected to the incoming line 56A of the fixed circuit 56 and the other to the outgoing line 56B of the fixed circuit 56.

[0091] The fixed connectors 66A, 66B are arranged here in a transverse end face of the stator 62.

[0092] To allow connection of at least one rotating circuit 58 to the rotating distributor 60, the rotor 64 includes at least one second connector, referred to as a rotating connector 68A, 68B. In the example shown in the figures, the rotor 64 here includes at least two rotating connectors 68A, 68B arranged on two separate stages of the rotating distributor 60. At least one rotating connector 68A of the first stage is connected to an inlet line 58A of the rotating circuit 58 to supply the heat exchanger with heat transfer fluid, and at least one rotating connector 68B is connected to an outlet line 58B of the rotating circuit 58 to discharge the heat transfer fluid after thermal regulation of the mold.

[0093] As this is a fluidic connection, each connector 66A, 66B, 68A, 68B is here formed by an orifice.

[0094] Each stage here has as many rotating 68A, 68B connectors as the processing unit 20 has processing stations 38.

[0095] The rotating connectors 68A, 68B are arranged here in an external cylindrical face of the rotor 64. The rotating connectors 68A, 68B of the same stage are arranged axially at the same level and are distributed regularly around the main axis "Z2".

[0096] The rotating distributor 60 includes at least one circuit 70A, 70B allowing communication between at least one fixed connector 66A, 66B of the stator 62 and at least one rotating connector 68A, 68B of the rotor 64, over at least one angular sector of the revolution of the rotor 64 relative to the stator 62.

[0097] Circuits 70A, 70B are here fluidic circuits.

[0098] Here, the fixed connectors 66A, 66B communicate with each associated connector 68A, 68B over one complete rotation of the rotor 64 relative to the stator 62.

[0099] In the example shown in [Fig. 4], the rotary distributor 60 comprises two fluid circuits 70A, 70B. The first fluid circuit 70A connects the fixed fluid inlet connector 66A to the rotating connectors 68A of the first stage. The second fluid circuit 70B connects the fixed fluid outlet connector 66B to the rotating connectors 68B of the first stage. The two fluid circuits 70A, 70B are sealed against each other to prevent mixing of the incoming and outgoing fluids.

[0100] Each fluidic circuit 70A, 70B includes a transfer chamber 72A, 72B which is radially interposed between the stator 62 and the rotor 64.

[0101] As shown in [Fig. 4], each transfer chamber 72A, 72B extends over a vertical height that is substantially equal to that of one floor. The two chambers 72A, 72B of each fluidic circuit 70A, 70B are axially superimposed.

[0102] The sealing of each distribution chamber 72A, 72B is ensured axially in both directions by two intermediate rings 74 which are interposed radially between the rotor 64 and the stator 62.

[0103] Each intermediate ring 74 is here mounted fixed relative to the stator 62 and sliding relative to the rotor 64.

[0104] Each intermediate ring 74 is made of a metallic material. An internal annular sealing gasket 76 made of elastomeric material is radially interposed between the stator 62 and each intermediate ring 74, and an external annular sealing gasket 78 (not shown) is radially interposed between the rotor 64 and each intermediate ring 74. The external sealing gasket 78 slides radially against the outer cylindrical face of the associated intermediate ring 74. The internal and external cylindrical faces of each intermediate ring 74 have a surface finish sufficiently smooth to ensure vertical sealing of each transfer chamber 72A, 72B.

[0105] Each transfer chamber 72A, 72B here has an annular shape.

[0106] Alternatively, each transfer chamber extends over at least one annular sector.

[0107] Each fixed connector 66A, 66B communicates with a chamber 72A, 72B of associated transfer via an axial duct 80A, 80B and at least one radial duct 82A, 82B which branches off the axial duct and opens radially into the associated transfer chamber 72A, 72B.

[0108] Each rotating connector 68A, 68B communicates with the associated transfer chamber 72A, 72B via a radial light 84A, 84B.

[0109] Alternatively, the processing stations 38 can also be supplied with electricity, for example to power accessories powered by an electric motor.

[0110] In such a processing unit 20, the processing stations 38, which are driven in rotation with the carousel 32, must be able to exchange electrical current with at least one external electrical circuit, called a fixed circuit, which is fixed relative to the frame 34. At least one electrical circuit rotating jointly with the carousel 32, called a rotating circuit 58, must be able to be connected with the circuit 56 fixed relative to the frame 34.

[0111] As this concerns electricity, the fixed circuit 56 comprises at least two cables.

[0112] The fixed circuit 56 is fixed relative to the ground. To allow each rotating circuit 58 to be supplied with electricity, the treatment unit 20 includes a rotating distributor 60.

[0113] Figure 10 shows an alternative embodiment in which the rotating distributor 60 supplies electricity to the treatment stations 38.

[0114] The electrical rotary valve 60 of [Fig. 10] is very similar to the fluidic rotary valve 60 of [Fig. 4]. Only the differences are described below.

[0115] The rotor 64 and the stator 62 are arranged in the same way as described previously. The stator 62 is mounted to rotate relative to the rotor 64 by means of at least one guide bearing 65, here two bearings 65. These are rolling bearings 65.

[0116] To allow connection of at least one fixed circuit 56 to the rotating distributor 60, the stator 62 includes at least one first connector, referred to as fixed connector 67A, 67B. In the example shown in the figures, the stator 62 includes two fixed connectors 67A, 67B, one fixed connector 67A being connected to a first cable (not shown) of the fixed circuit 56 and the other fixed connector 67B being connected to a second cable of the fixed circuit 56.

[0117] The fixed connectors 67A, 67B are arranged here in a transverse end face of the stator 62.

[0118] To allow connection of at least one rotating circuit 58 to the rotating distributor 60, the rotor 64 includes at least one second connector, referred to as the rotating connector 69A, 69B. In the example shown in the figures, the rotor 64 here includes at least two rotating connectors 69A, 69B arranged on two separate stages of the rotating distributor 60. The at least one rotating connector 69A of the first stage is connected to a first cable (not shown) of the rotating circuit 58, and the at least one rotating connector 69B is connected to a second cable (not shown) of the rotating circuit 58.

[0119] As regards an electrical connection, each connector 67A, 67B, 69A, 69B is here formed by an electrical plug, such as a male or female plug, intended to cooperate with a complementary plug arranged at the end of the associated cable.

[0120] Each stage here has as many rotating 69A, 69B connectors as the processing unit 20 has 38 processing stations.

[0121] As in the embodiment shown in [Fig.4], the rotating connectors 69A, 69B are arranged here in an external cylindrical face of the rotor 64.

[0122] The rotating distributor 60 includes at least one circuit 71 A, 71B allowing communication between at least one fixed connector 67A, 67B of the stator 62 and at least one rotating connector 69A, 69B of the rotor 64, over at least one angular sector of the revolution of the rotor 64 relative to the stator 62.

[0123] Circuits 71 A, 71 B are here electrical circuits.

[0124] In the example shown in [Fig. 4], the rotary distributor 60 comprises two electrical circuits 71A, 71B. The first electrical circuit 71A connects the fixed connector 67A to the rotating connectors 69A of the first stage. The second electrical circuit 71B connects the fixed connector 66B to the rotating connectors 68B of the first stage.

[0125] Each electrical circuit 71 A, 71 B includes an electrically conductive brush 73 A, 73 B which is radially interposed between the stator 62 and the rotor 64. Each brush 73 A, 73 B is fixed to one of the rotor 64 or the stator 62 by one end and has a second free end 75 A, 75 B which rubs against an electrically conductive ring 77 A, 77 B which is fixed to the other of the stator 62 or the rotor 64. Here, the brushes 73 A, 73 B are fixed to the rotor 64 and the rings 77 A, 77 B are fixed to the stator 62.

[0126] The sealing of the space in which the brushes 73A, 73B are located is here ensured axially in both directions by two intermediate rings 74 which are interposed radially between the rotor 64 and the stator 62.

[0127] Each intermediate ring 74 is here mounted fixed relative to the stator 62 and sliding relative to the rotor 64.

[0128] Each intermediate ring 74 is made of a metallic material. An internal annular sealing gasket 76 made of elastomeric material is radially interposed between the stator 62 and each intermediate ring 74, and an external annular sealing gasket 78 (not shown) is radially interposed between the rotor 64 and each intermediate ring 74. The external sealing gasket 78 slides radially against the outer cylindrical face of the associated intermediate ring 74. The internal and external cylindrical faces of each intermediate ring 74 have a surface finish sufficiently smooth to ensure vertical sealing of each transfer chamber 72A, 72B.

[0129] Each fixed connector 66A, 66B communicates with the associated ring 77A, 77B via a conductive wire 81A, 81B.

[0130] Each rotating connector 69A, 69B communicates with the associated brush 73A, 73B via an associated conductor wire 83A, 83B.

[0131] In an alternative not shown, the rotating distributor 60 can be a hybrid electrical and fluidic distributor.

[0132] Regardless of the embodiment of the rotating distributor 60, the various seals interposed between the rotor 64 and the stator 62, formed in particular by the guide bearings 65 and / or the intermediate rings 74 and / or the seals 76, 78, are liable to rub against and cause the stator 62 to rotate with the rotor 64 during the rotation of the carousel 32. Thus, during the rotation of the carousel 32, the stator 62 is subjected to a rotational torque in a first direction, referred to as the stator torque "Cs". The first direction is the direction of rotation of the carousel 32, here clockwise.

[0133] To prevent the pipes 56A, 56B of the fixed circuit 56 from becoming wrapped around the rotating distributor 60, until they are torn off, it is important to prevent the rotation of the stator 62. The stator 62 is immobilized in rotation relative to the frame 34 around the main axis "Z2" by means of an anti-torque device 86.

[0134] Such an anti-torque device 86 mainly comprises a rigid linking element 88 which is intended to be linked at least in rotation about the main axis "Z2" with the stator 62. The rigid linking element 88 is intended to be fixed relative to the frame 34 by means of a rigid structure 90.

[0135] By way of non-limiting example, the connecting element 88 is formed by a fork which cooperates with flats 91 of a stator section 62 which protrudes axially relative to the rotor 64.

[0136] The rigid structure 90 includes, for example, at least one column 93 which extends parallel to the main axis "Z2" between the frame 34 and the connecting element 88.

[0137] Certain elements of the anti-torque device, and in particular the rigid structure 90, have sufficient breaking strength to withstand the stator torque "Cs" during normal operation. However, when the rotating distributor 60 seizes, there is a risk that one of the components of the rigid structure 90 will break. The stator torque "Cs" can become even higher if the inertia of such a carousel 32 is extremely high. In this case, the anti-torque device 86 no longer performs its function, and the stator 62 is free to rotate with the rotor 64.

[0138] Seizing can occur through increased friction between the sliding linings, in particular the intermediate rings 74 and / or the sealing rings 76, 78, and the stator 62 or the rotor 64. This type of seizing is more frequent on fluidic rotating distributors 60 due to the presence of numerous sliding linings.

[0139] Seizing can also occur by blocking at least one bearing 65.

[0140] To prevent this situation from occurring, the invention proposes a method for diagnosing the condition of the rotating distributor 60 which includes a first step "El" of verifying that the stator torque "Cs" is less than a maximum permissible value "Cmax" by means of a torque monitoring device 92.

[0141] The maximum permissible "Cmax" value is preferably much lower than a critical value that would cause the weakest element of the anti-torque device 86 to break. The aim is to be able to intervene before any risk of breakage arises.

[0142] The monitoring device 92 includes a monitoring element 94 for the stator torque "Cs". The stator torque "Cs" is transmitted to the frame 34 via the monitoring element 94 for the stator torque "Cs". More precisely, the entire force exerted by the stator torque "Cs" passes through the monitoring element 94.

[0143] According to a first embodiment of the invention shown in [Fig. 5], the stator torque monitoring device 94 is a force sensor comprising a strain gauge 96. The strain gauge 96 is arranged on a transmission part 98, one end of which is fixed to the connecting element 88 and the other end of which is fixed to the rigid structure 90 of the anti-torque device 86. The transmission part 98 is made of a rigid metallic material. When a stator torque 98 is applied to one end of the transmission part 98, the strain gauge 96 sends a signal representative of the intensity of the stator torque 96 to an electronic control unit 100.

[0144] The monitoring device 94 is thus formed by a sensor which is capable of measuring a representative value of the stator torque “Cs”.

[0145] As shown in [Fig.6], the first verification step “El” includes a first substep “El-1” of measuring the stator torque “Cs” using the monitoring device 92, and then a second substep “El-2” of comparing the measurement with the maximum permissible value “Cmax”.

[0146] If the measured stator torque “Cs” is less than the maximum permissible value “Cmax”, the procedure is repeated without change. Conversely, if the measured stator torque “Cs” is greater than the maximum permissible value “Cmax”, an alert is issued by the electronic control unit 100 to warn that maintenance of the rotary distributor 60 is required, as indicated in substep “El-3” of [Fig.6].

[0147] Advantageously, but not necessarily, the process also includes a second step "E2" of verification that the stator torque "Cs" is greater than a minimum permissible value "Cmin" by means of said torque monitoring device 92.

[0148] It has been observed that, when the sealing components, particularly the spacer rings 74 and the sealing gaskets 76, 78, begin to wear, the stator torque "Cs" tends to decrease. Thus, an excessive drop in the stator torque "Cs" indicates a risk of fluid leakage due to excessive wear of these components.

[0149] The same monitoring device 92 as for the first step "El" is used here to implement the second step "E2".

[0150] As shown in [Fig.6], the second verification step “E2” is triggered following the second sub-step “El-2” of the first verification step “El”, when the measured stator torque “Cs” is less than the maximum permissible value “Cmax”.

[0151] The second step “E2” includes a sub-step “E2-1” of comparing the measurement obtained during the first sub-step “El-1” of the first verification step “El” with the minimum permissible value “Cmin”.

[0152] If the measured stator torque “Cs” is greater than the minimum permissible value “Cmin”, the procedure is repeated without change. Conversely, if the measured stator torque “Cs” is less than the minimum permissible value “Cmin”, an alert is issued by the electronic control unit 100 to warn that maintenance of the rotary distributor 60 is required, as shown in substep “E2-2” of [Fig. 6].

[0153] According to a second embodiment shown in Figures 7 and 8, instead of being a sensor, the stator torque monitoring element 94 is an element 94 that allows the stator 62 to pivot relative to the frame 34 when the stator torque "Cs" exceeds the maximum permissible value "Cmax". Below the maximum permissible value "Cmax", the monitoring element 94 couples the stator 62 to the frame 34.

[0154] The monitoring device 94 is for example a torque limiter calibrated to be disengaged at the maximum permissible "Cmax" value.

[0155] Alternatively, the monitoring device 94 is an element forming a mechanical fuse calibrated to the maximum permissible value "Cmax". It may be a part that breaks when the stator torque "Cs" reaches the maximum permissible value "Cmax", or it may be a resettable fuse.

[0156] To prevent the stator 62 from rotating without limit when the monitoring member 94 no longer fulfills its function of coupling the connecting element 88 with the frame 34, it is provided that a finger 102 fixed with respect to one of the connecting element 88 or the frame 34 comes to rest against a stop 104 fixed with respect to the other of the connecting element 88 or the frame 34.

[0157] Here, the finger 102 is fixed to the connecting element 88. It extends radially. The stop 104 is supported by a plate 106 which is fixed to the rigid structure 90. When the stator torque "Cs" exceeds its maximum permissible value "Cmax", the finger 102 is driven to pivot in the same direction as the rotor 64 until the finger 102 comes to rest against the stop 104 to prevent the stator 62 from pivoting relative to the frame 34.

[0158] A motion detection switch 108 is also provided, which is activated when the stator 62 is pivoted relative to the frame 34. The detection switch 108 is here activated by the finger 102. The activation of the switch 108 sends to the electronic control unit 100 a signal representing that the stator torque “Cs” exceeds the maximum permissible torque “Cmax”.

[0159] In this embodiment, the diagnostic method for the condition of the rotating distributor 60 includes only the first step "El" of verifying that the stator torque "Cs" is less than a maximum permissible value "Cmax".

[0160] As shown in [Fig.9], the first verification step "El" includes a first sub-step "El-1" for checking the state of the detection switch 108.

[0161] If the switch 108 is in its inactive state, this means that the stator torque “Cs” is less than the maximum permissible value “Cmax”, the process is repeated without change.

[0162] Conversely, if switch 108 has been activated, this means that the stator torque “Cs” is greater than the maximum permissible value “Cmax”. An alert is then issued by the electronic control unit 100 to warn that maintenance of the rotary distributor 60 is required, as shown in substep “El-3” of [Fig.6].

Claims

Demands

1. Method for diagnosing the condition of a rotating distributor (60) for a hollow body processing unit (20) made of thermoplastic material comprising a carousel (32) mounted to rotate on a frame (34) fixed around a central axis (Zl), the rotating distributor (60) comprising: - a rotor (64) mounted fixed relative to the carousel (32); - a stator (62) on which the rotor (64) is mounted to rotate coaxially around the central axis (Zl), the rotor (64) being capable of applying to the stator (62) a rotational torque in a first direction, called stator torque (Cs), during the rotation of the carousel (32), the stator (62) being immobilized in rotation relative to the frame (34) around the axis (Zl) of rotation by means of an anti-torque device (86);- at least one fluidic or electrical circuit (70A, 70B) enabling communication between at least one first connector, referred to as fixed connector (66A, 66B), of the stator (62), and at least one second connector, referred to as rotating connector (68A, 68B), of the rotor (64) during the rotation of the rotor (64) relative to the stator (62); characterized in that the method includes a first step (El) of verifying that the stator torque (Cs) is less than a maximum permissible value (Cmax) by means of a torque monitoring device (92).

2. Method according to the preceding claim, characterized in that the torque monitoring device (92) comprises a monitoring element (94) calibrated to allow a pivoting of the stator (62) in said first direction relative to the frame (34) when the stator torque (Cs) exceeds the maximum permissible value (Cmax).

3. Method according to the preceding claim, characterized in that the torque monitoring device (92) comprises a motion detection switch (108) actuated when the stator (62) pivots in the first direction.

4. A method according to claim 1, characterized in that the torque monitoring device (92) comprises a sensor (98, 96) which is capable of measuring a representative value of the stator torque (Cs), the first verification step (El) comprising a first substep (El-1) of measuring the stator torque (Cs) and a second sub-step (El-2) of comparison of the measurement with the maximum permissible value (Cmax).

5. A method according to any one of the preceding claims, characterized in that it comprises a second step (E2) of verifying that the stator torque (Cs) is greater than a minimum permissible value (Cmin) by means of said torque monitoring device (92).

6. Method according to claim 5, characterized in that the torque monitoring device (92) comprises a sensor (96, 98) which is capable of measuring the value of the stator torque (Cs), the second verification step (E2) comprising a first substep (E2-1) of measuring the torque and a second substep (E2-2) of comparing the measurement with the minimum permissible value (Cmin).

7. A method according to claim 6 taken in combination with claim 4, characterized in that the same sensor (96, 98) is used during the first verification step (E1) and during the second verification step (E2).

8. A thermoplastic hollow body processing unit (20) comprising a carousel (32) mounted to rotate on a fixed frame (34) about a central axis (Zl), the processing unit (20) comprising a rotating distributor (60) comprising: - a rotor (64) mounted fixed relative to the carousel (32); - a stator (62) on which the rotor (64) is mounted to rotate coaxially about the central axis (Zl), the rotor (64) being capable of applying to the stator (62) a rotational torque, called stator torque (Cs), during the rotation of the carousel (32), the stator (62) being immobilized in rotation relative to the frame (34) about the axis (Zl) of rotation by means of an anti-torque device (86);- at least one fluidic or electrical circuit (70A, 70B) enabling communication between at least one first connector, referred to as connector (66A, 66B), fixed, of the stator (62), with at least one second connector, referred to as connector (68A, 68B), rotating, of the rotor (64) during the rotation of the rotor (64) relative to the stator (62); characterized in that the stator torque (Cs) is transmitted to the frame (34) via a stator torque (Cs) monitoring device (94).

9. Processing unit (20) according to the preceding claim, characterized in that the torque monitoring organ (94) stator is a (98, 96) force sensor comprising a (96) strain gauge.

10. Processing unit (20) according to the preceding claim, characterized in that the stator torque monitoring element (94) comprises a torque limiter calibrated to the maximum permissible value (Cmax).

11. Processing unit (20) according to claim 8, characterized in that the monitoring member (94) is an element forming a mechanical fuse calibrated to the maximum permissible value (Cmax).

12. Processing unit (20) according to any one of claims 8 to 11, characterized in that the monitoring element (94) is part of a stator torque monitoring device (92).

13. Processing unit (20) according to any one of claims 8 to 12, characterized in that said processing unit (20) is a preform forming unit.