Device for straightening and aligning preforms by centrifugation

Abstract

The invention relates to a device (10) for aligning and straightening preforms, which comprises a bowl centrifuge (20) comprising: - a central plate (28) rotating about a vertical axis (B); - a peripheral rail (52); - a peripheral gap (56) which extends at least along an angular sector (20B) for straightening the preforms (12); characterised in that it comprises an annular peripheral plate (34) which is mounted so as to rotate about the central plate (28) independently of the central plate (28), the gap (56) being delimited between the rail (52) and a circular outer edge (26) of the peripheral plate (34).

Description

DEVICE FOR STRAIGHTENING AND ALIGNING PREFORMS BY CENTRIFUGATION TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a device for aligning in a row and straightening preforms which comprises a centrifuge bowl comprising:

[0002] - a horizontal circular central plate rotating around a vertical axis, an upper face of which is intended to receive bulk preforms;

[0003] - a fixed peripheral railing which extends vertically projecting above the upper face of the central plate and against which the preforms are intended to be projected and aligned by centrifugation during the rotation of the central plate;

[0004] - a peripheral gap which extends at least along an angular sector of straightening of the preforms to allow the straightening of preforms aligned along the railing by tilting a body of the preforms in the gap while the neck is supported above the level of the upper face of the central plate.

[0005] TECHNICAL BACKGROUND OF THE INVENTION

[0006] The device is intended to be implemented in a facility for manufacturing containers made of thermoplastic material, particularly polyethylene terephthalate (PET), by forming, particularly by blowing or stretch-blow molding, preforms. Such a facility makes it possible to produce containers in very large series at very high rates, for example, greater than 85,000 bottles per hour.

[0007] According to a well-known technique, such containers are produced in two main stages. In a first stage, a PET preform is injection-molded or injection-compression-molded. This preform comprises a substantially tubular body which is closed at one of its axial ends, the opposite end being open by means of a neck. The neck has, from this injection-molding operation, the final shape of the container neck. Generally, the container neck has a thread or a groove.

[0008] The preform generally comprises an annular support face which projects radially outwards relative to the rest of the body and which is oriented axially towards the closed end of the body. Such a support face is for example carried by an annular support collar which extends radially outwards relative to the rest of the preform and which is arranged at the base of the neck.

[0009] There are installations in which the preforms, once injected, are directly transmitted to a forming unit, each preform being transported individually.

[0010] However, in many cases, preforms are manufactured by injection at one location and are blow-molded to the final container shape at a second location on a specific manufacturing facility. Such technology allows the blow-molding operation to be carried out as close as possible to the bottling location, and the injection operation can be carried out at any location. Indeed, it is relatively easy and inexpensive to transport small preforms, while transporting containers after blowing has the disadvantage of being economically unprofitable due to their very large volume.

[0011] In the case where the injection station and the forming manufacturing installation are two completely independent machines, the preforms are generally delivered in bulk. The forming manufacturing installation therefore has a preform supply device which is equipped with a device for aligning the preforms in a row and for straightening them. The present invention relates to such a device.

[0012] An alignment and straightening device comprising a centrifuge bowl has already been proposed. The preforms are thrown in bulk onto a rotating plate forming the bottom of the bowl. The preforms are then projected by centrifugal force against a peripheral railing. A radial gap between the railing and the rotating plate allows the body of the preforms to pass through while retaining them by their collar. The preforms are thus aligned at the periphery of the bowl, their main axis having a substantially vertical orientation under the effect of gravity.

[0013] Such an installation is notably described in the document

[0014] WO 2016 / 038634, in which the preforms are discharged by a conveyor into a concave feed zone formed by a turntable inclined relative to a horizontal orientation track. Thus, the preforms are moved to be aligned by a centrifugal force generated by the turntable from the concave feed zone to the orientation track. This concave feed zone is intended to temporarily store the preforms before their orientation, but does not participate in the alignment step.

[0015] Such preforms aligned and straightened in a row will hereinafter be called "correctly positioned preforms".

[0016] The correctly positioned preforms are then driven towards a tangential outlet of the bowl under the effect of the rotational movement of the turntable.

[0017] In this type of device, it is sometimes necessary to slow down or accelerate the rotation of the turntable in order to adapt the conveying speed of the aligned and / or straightened preforms along the railing according to the quantity of preforms present in the centrifuge bowl or downstream of the centrifuge bowl.

[0018] For example, when the centrifuge bowl is saturated with preforms, it is best to increase the rotation speed of the plate to speed up the evacuation of the preforms.

[0019] It can also happen that preforms get stuck, and it is then necessary to turn the central plate in the opposite direction to unblock the preforms before starting it to rotate again in the right direction.

[0020] However, variations in the rotation speed of the plate have a direct influence on the centrifugal force which throws the preforms against the railing.

[0021] If the centrifugal force becomes too great, the preforms may be damaged or even propelled out of the bowl.

[0022] Conversely, if the centrifugal force is insufficient, the preforms may accumulate in the center of the tray or not be correctly aligned against the railing.

[0023] It is therefore preferable to limit the rotation speed of the plate to limit the centrifugal force in both directions.

[0024] To solve the above problems, it has already been proposed to equip such a device with different means to avoid blockages by expelling incorrectly positioned preforms or to regulate the quantity of preforms that feed the bowl.

[0025] However, these means are not always sufficient to guarantee continuous proper functioning. In addition, these means can be expensive.

[0026] Furthermore, current means do not allow the preform flow rate to be increased beyond a certain threshold.

[0027] BRIEF SUMMARY OF THE INVENTION

[0028] The invention provides a device for aligning in a row and straightening preforms which comprises a centrifuge bowl comprising:

[0029] - a horizontal circular central plate rotating around a vertical axis, an upper face of which is intended to receive bulk preforms;

[0030] - a fixed peripheral railing which extends vertically projecting above the upper face of the central plate and against which the preforms are intended to be projected and aligned by centrifugation during the rotation of the central plate;

[0031] - a peripheral gap which extends at least along an angular sector of straightening of the preforms to allow the straightening of preforms aligned along the railing by tilting a body of the preforms in the gap while the neck is supported above the level of the upper face of the central plate.

[0032] The device produced according to the teachings of the invention is characterized in that it comprises an annular peripheral plate which is mounted rotating around the central plate independently of the central plate, the gap being delimited between the railing and a circular outer edge of the peripheral plate and in that the peripheral plate and the central plate are mounted rotating coaxially around the vertical axis.

[0033] According to another characteristic of the device produced according to the teachings of the invention, the central plate is driven by a rotation speed which is controlled as a function of the centrifugal force required according to the weight of the preforms to be aligned and the peripheral plate is driven by a rotation speed which is controlled as a function of the speed of movement required for the preforms around the centrifuge bowl.

[0034] According to another characteristic of the device produced according to the teachings of the invention, the central plate has a flat upper face orthogonal to the vertical axis.

[0035] According to another characteristic of the device produced according to the teachings of the invention, the central plate has an upper convex face axisymmetrical with respect to the vertical axis.

[0036] According to another characteristic of the device produced according to the teachings of the invention, the peripheral plate comprises an upper face which is coplanar with a peripheral edge of the upper face of the central plate.

[0037] According to another characteristic of the device produced according to the teachings of the invention, the peripheral plate is arranged around the central plate with a radial clearance reserved allowing its independent rotation.

[0038] According to another characteristic of the device produced according to the teachings of the invention, the radial clearance is less than 2 mm, preferably less than 1 mm.

[0039] According to another characteristic of the device produced according to the teachings of the invention, the central plate is driven in rotation by a first motor, while the peripheral plate is driven in rotation by a second motor.

[0040] According to another characteristic of the device produced according to the teachings of the invention, the peripheral plate is mounted on an orientation crown.

[0041] According to another characteristic of the device produced according to the teachings of the invention, the peripheral plate is produced in several angular segments.

[0042] According to another characteristic of the device produced according to the teachings of the invention, the peripheral plate comprises an inner crown and a removable outer crown to allow the width of the gap to be adjusted according to the dimensions of the preforms to be straightened.

[0043] The invention also relates to a method for controlling the alignment and straightening device according to which the rotation speed of the central plate is controlled according to the centrifugal force required according to the weight of the preforms to be aligned, while the rotation speed of the peripheral plate is controlled according to the required movement speed for the preforms around the centrifuge bowl. BRIEF DESCRIPTION OF THE FIGURES

[0044] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which one will refer to the appended drawings briefly described below.

[0045] This is a perspective view which schematically represents a device for aligning and straightening preforms comprising a centrifuge bowl in accordance with the teachings of the invention.

[0046] This is a front view which represents a preform adapted for use with the device of the, the axis of the preform being here oriented vertically.

[0047] This is a perspective view that only shows the bottom of the centrifuge bowl, comprising a central tray and a peripheral tray.

[0048] This is a sectional view according to section plane 4-4 of the.

[0049] This is a top view showing the centrifuge bowl of the.

[0050] This is a radial sectional view of an alignment sector of the centrifuge bowl of which shows a peripheral railing and the bottom of the centrifuge bowl as well as an aligned preform.

[0051] This is a perspective view that represents a spillway of the device.

[0052] This is a top view showing part of the centrifuge bowl alignment sector, as well as the various stages of the path of a preform poured into the centrifuge bowl.

[0053] This is a radial sectional view of a centrifuge bowl straightening sector of the which shows the peripheral railing and the centrifuge bowl turntable as well as an aligned and straightened preform.

[0054] This is a schematic view along a radial direction which represents a preform aligned along the railing in the alignment sector of the centrifuge bowl of the.

[0055] This is a top view of the.

[0056] This is a view similar to that of which depicts the preform of the being straightened at the beginning of the straightening sector of the centrifuge bowl of the.

[0057] This is a top view of the.

[0058] This is a view similar to that of which shows the preform of the straightened in the straightening sector of the centrifuge bowl of the.

[0059] This is a top view of the.

[0060] This is a top view showing an area of ​​the centrifuge bowl located between the straightening sector and an outlet sector and which includes a detangling wheel.

[0061] DETAILED DESCRIPTION OF THE FIGURES

[0062] In the remainder of the description, elements having an identical structure or similar functions will be designated by the same references.

[0063] In the remainder of the description, the following guidelines will be adopted without limitation:

[0064] - radial "R" directed from the inside to the outside from the axis "B" of rotation of the central plate 28;

[0065] - tangential "T" which is orthogonal to the radial direction "R" and which extends parallel to the plane of the central plate 28, directed from upstream to downstream according to the positive direction of rotation of the central plate 28;

[0066] - vertical "V" directed parallel to the axis "B" of rotation of the central plate 28, from bottom to top in the opposite direction of Earth's gravity.

[0067] A positive rotational speed is also defined when a platter rotates clockwise with reference to the drawings, and a negative rotational speed when a platter rotates in the opposite direction.

[0068] A device 10 is shown for aligning in a row and straightening preforms 12 intended to be part of an installation (not shown) for manufacturing containers made of thermoplastic material by forming, in particular by blowing or by stretch-blow molding, the preforms 12.

[0069] An example of a preform 12 intended to be used with the alignment and straightening device 10 is illustrated in. Such a preform 12 is made of thermoplastic material, here polyethylene terephthalate (PET). It is conventionally obtained by injection molding. It has a substantially axisymmetric shape around a main axis "A" shown vertically in.

[0070] It comprises a body 14 in the form of an elongated tube along the main axis "A" having a closed axial end and which has at its opposite end, shown at the top, a neck 16 open axially.

[0071] The preform 12 also comprises an annular support face 18 which is oriented axially towards the closed end of the preform 12, which projects radially relative to the rest of the body 14. The support face 18 is arranged above a center "G" of gravity of the preform 12. The support face 18 goes around the preform 12 either continuously, as illustrated in, or discontinuously (not shown).

[0072] When the support face is discontinuous, the annular face is for example formed of disjoint segments which go around the preform 12 and which are nevertheless sufficiently close together so that the preform 12 can be supported between two diametrically opposite supports whatever the position of the preform 12 around its main axis.

[0073] In the example shown in , the base of the neck 16, at the junction with the body 14, has a collar which extends radially projecting relative to the rest of the preform 12. The lower face of the collar thus forms said support face 18.

[0074] In a variant not shown, the collar can be arranged elsewhere than at the base of the neck, for example at the level of the rim.

[0075] According to another variant not shown, the support face is for example formed by a lower face of a thread of the neck.

[0076] According to yet another variant not shown, the support face is attached to the preform, for example by means of a plug.

[0077] An external diameter "D1" of the support face 18, in this case of the collar, is thus greater than the maximum external diameter "D2" of the body 14, located here directly under the collar. In the example shown in , the closed end section of the body 14 here has a minimum external diameter "D3".

[0078] The neck 16 has its final shape, while the body 14 is intended to be stretched during a subsequent forming operation to form the body of the finished container.

[0079] Furthermore, the weight of the body 14 of the preforms 12 used is greater than the weight of the neck 16, including that of the flange. A center "G" of gravity of the preform 12 is therefore located under the support face 18 with reference to the. Thus, a preform 12 supported by its support face 18 while resting on two diametrically opposed supports will naturally orient itself by gravity with the neck 16 at the top.

[0080] The example shown in is non-limiting. It will be understood that the alignment and straightening device 10 and the associated method are intended to be applied to any type of preform 12 having a support face 18 projecting radially relative to the rest of the body 14, and having a center of gravity axially offset towards the body 14 relative to said support face 18.

[0081] As will be explained later, the alignment and straightening device 10 is capable of processing batches of identical preforms 12, the format of the preforms 12 being capable of varying depending on the batch. As a result, different adjustments are capable of being made to the alignment and straightening device 10 during a change of format of preform 12.

[0082] Returning to the, the alignment and straightening device 10 mainly comprises a centrifuge bowl 20 as well as an output conveyor 22 for the row of correctly positioned and straightened preforms 12, hereinafter referred to as "correctly positioned preforms 12". The output conveyor 22 is intended to convey the correctly positioned preforms 12 to distribute them one by one to individual handling means for each preform 12 of a following processing unit (not shown) of the manufacturing installation, for example a thermal conditioning unit for the preforms 12.

[0083] The centrifuge bowl 20 has a horizontal circular bottom 24 with a central vertical axis "B". The bottom 24 thus has a circular outer edge 26. The bottom 24 delimits vertically downwards the interior volume of the centrifuge bowl 20.

[0084] The bottom 24 has an external diameter much greater than the dimensions of the preforms 12.

[0085] As shown in Figures 3 and 4, the bottom 24 comprises a first horizontal circular central plate 28 coaxial with the central axis "B". It has a flat circular upper face orthogonal to said central axis "B". It has an outside diameter smaller than the outside diameter of the bottom 24. The central plate 28 is delimited radially by an outer edge 29. The central plate 28 is mounted to rotate about the central axis "B".

[0086] According to a variant of the invention (not shown), the central plate has a convex shape with a downward slope outwards from the central axis. The central plate has an axisymmetric shape with respect to the central axis. The slope is preferably of the order of a few degrees. The plate has, for example, a conical or truncated cone shape.

[0087] The central tray 28 is here carried by a support table 30 which is fixed to the ground. The support table 30 has feet which are advantageously adjustable in height to allow the position of the central tray 28 to be adjusted.

[0088] The first central plate 28 can be driven in rotation by a first motor 32 at a first angular speed V1 called centrifugation speed V1. The first motor 32 is for example arranged under the central plate 28.

[0089] As will be explained later, the upper face of the central plate 28 is intended to receive preforms 12 in bulk. The rotation of the central plate 28 makes it possible to project the preforms 12 radially outwards by centrifugation.

[0090] The first central plate 28 is for example driven in rotation at a constant centrifugation speed V1, here in a positive direction in top view. Alternatively, the centrifugation speed V1 is capable of varying. Preferably, the centrifugation speed V1 is always strictly positive so that a centrifugal force is permanently exerted on the preforms 12. The centrifugation speed V1 is for example controlled so that the outer edge 29 of the central plate 28 moves between 2 and 3 m / s.

[0091] The bottom 24 of the centrifuge bowl 20 further comprises a second annular peripheral plate 34. The second peripheral plate 34 is arranged around the central plate 28. It has a flat annular upper face. The second peripheral plate 34 is delimited radially by a circular inner edge 36 and by a circular outer edge forming the circular outer edge 26 of the bottom 24. It is mounted to rotate independently of the central plate 28.

[0092] The peripheral plate 34 here has a radial width, between the inner edge 36 and the outer circular edge 26, which is less than the radius of the central plate 28. The radius of the central plate 28 is for example greater than or equal to 10 times the radial width of the peripheral plate 34. The radial width of the peripheral plate 34 is for example between one and two times the length of a preform 12.

[0093] Preferably, the peripheral plate 34 and the central plate 28 are mounted rotating coaxially around the vertical axis "B" which forms a common axis. The upper face of the peripheral plate 34 is thus coplanar with the upper surface of the central plate 28.

[0094] In a variant of the invention not shown, when the central plate 28 has a convex upper face, the peripheral plate 34 is arranged coplanar with the peripheral edge 29 of the central plate 28.

[0095] To allow the independent rotation of the peripheral plate 34 relative to the central plate 28, a radial clearance "j" is reserved between the outer edge 29 of the central plate 28 and the inner edge 36 of the peripheral plate 34. The radial clearance "j" has a dimension much smaller than the diameter of the body 14 of the preforms 12 to be treated so that a preform 12 can slide from the central plate 28 to the peripheral plate 34 without being significantly slowed down by the presence of the radial clearance "j". The radial clearance "j" is for example less than 2 mm, preferably less than or equal to 1 mm. Thus, the upper face of the peripheral plate 34 extends substantially in the extension of the upper face of the central plate 28.

[0096] The peripheral plate 34 is mounted on a ball slewing ring 38. The slewing ring 38 is here fixed to the table 30, below the level of the central plate 28. It comprises an upper ring 40 on which the peripheral plate 34 is fixed and a lower ring 42 which is fixed to the table 30. The upper ring 40 is mounted in rotation relative to the lower ring 42 by means of balls 44 or rollers.

[0097] To facilitate the assembly and / or replacement of the peripheral plate 34, the latter is made of several angular segments 34A, 34B, 34C which are intended to be fixed one after the other on the orientation ring 38 to reconstitute the peripheral plate 34. The peripheral plate 34 is preferably divided into identical angular segments 34A, 34B, 34C distributed regularly around the central axis "B". The peripheral plate 34 is here formed of at least two angular segments, preferably at least three angular segments 34A, 34B, 34C.

[0098] The peripheral plate 34 is driven in rotation by a second motor 46 at a second angular speed V2, called conveying speed V2. The second motor 46 is for example arranged below the level of the central plate 28.

[0099] The second motor 46 drives, for example, the upper ring 40 of the slewing ring 38 in rotation by means of a pinion 48 which meshes with a toothing 50 of the upper ring 40. The toothing 50 is, for example, arranged on an outer face or an inner face of the upper ring 40.

[0100] Alternatively, the second motor 46 is integrated into the slewing ring 38. It is thus a motorized slewing ring 38.

[0101] Alternatively, the second motor 46 is a linear motor.

[0102] Preferably, the second motor 46 is independent of the first motor 32.

[0103] Alternatively, one of the second motor 46 and the second motor 32 is slaved to the other.

[0104] In a variant of the invention not shown, the peripheral plate 34 is driven in rotation by the first motor 34 via motion transmission members. The motion transmission members may comprise a gearbox or a speed reducer so that the peripheral plate 34 can rotate at a speed different from that of the central plate 28.

[0105] As will be explained later, the upper face of the peripheral plate 34 is intended to convey around the centrifuge bowl 20 preforms 12 which have been aligned by centrifugation on the edge of the centrifuge bowl 20. The rotation of the peripheral plate 34 makes it possible to move the preforms 12 circumferentially.

[0106] The second peripheral plate 34 is for example driven in rotation at a constant conveying speed V2, preferably in the same direction as the first central plate 28. Alternatively, the conveying speed V2 is likely to vary, for example depending on the number of preforms 12 present in the centrifuge bowl 20 or depending on the supply requirements of the manufacturing installation.

[0107] Preferably, the conveying speed V2 is always strictly positive so as to drive the preforms 12 towards an outlet of the centrifuge bowl 20, as will be explained later. Occasionally, the conveying speed V2 may be zero, or even negative, the peripheral plate 34 then rotating in a direction opposite to that of the central plate 28.

[0108] The conveying speed V2 of the peripheral tray 34 can be regulated according to the quantity of preforms 12 accumulated in the output conveyor 22. This quantity of preforms 12 can be detected by sensors (not shown) located in the output conveyor 22. In other words, if the quantity of preforms 12 in the output conveyor 22 is not sufficient to feed the next processing unit, then the conveying speed V2 of the peripheral tray 34 can be increased.

[0109] The interior volume of the centrifuge bowl 20 is delimited radially outwardly by a fixed peripheral railing 52 which is here fixed to the support table 30. The railing 52 extends vertically projecting above the upper face of the peripheral plate 34. Over the entire periphery of the centrifuge bowl 20, the railing 52 extends radially at a distance from the outer edge 29 of the central plate 28. Thus, preforms 12 which are in contact with the railing 52 are always supported by the peripheral plate 34, regardless of its position in the centrifuge bowl 20.

[0110] This railing 52 has in particular the first function of retaining the preforms 12 projected outwards by the centrifugal force produced by the rotation of the central plate 28, and the second function of guiding the movement of the preforms 12 to an outlet passage 53 of the centrifuge bowl 20 which is arranged in the railing 52, as can be seen in particular in the.

[0111] The preforms 12 are intended to be poured in bulk onto the central plate 28 via a spillway 54 fixed relative to the table 30. The spillway 54 is here arranged in the center of the central plate 28. The spillway 54 is designed to pour the preforms 12 in bulk, radially towards a receiving portion 52A of the railing 52. The spillway 54 is here in the form of a slide supplied with preforms 12 from above via a lifting belt (not shown). The top of the spillway 54 nevertheless has a relatively low height, for example approximately 40 cm above the central plate 28.

[0112] As illustrated in, for the purposes of the description, the centrifuge bowl 20 will be divided into three angular sectors fixed relative to the support table 30.

[0113] A first angular sector 20A for aligning the preforms 12 extends opposite the outlet of the spillway 54. This angular alignment sector 20A includes the portion 52A for receiving the railing 52.

[0114] A second angular sector 20B for straightening the aligned preforms 12 is arranged directly downstream of the first angular alignment sector 20A in the positive direction of rotation. In a non-limiting manner, it extends here generally over 180°.

[0115] A third angular sector 20C for exiting the correctly positioned preforms 12 is arranged directly downstream of the second angular straightening sector 20B and directly upstream of the first angular alignment sector 20A. At the downstream end of this exit sector 20C, the exit passage 53 for the preforms 12 is open in the railing 52 to allow the correctly positioned preforms 12 to be guided towards the conveyor 22. The conveyor 22 here passes behind the receiving portion 52A of the railing 52.

[0116] The name of each of these sectors 20A, 20B, 20C provides an indication of their function. It will be understood subsequently that preforms 12 incorrectly aligned at the level of the first alignment sector 20A can nevertheless be aligned and straightened at the level of the second angular sector 20B according to the circumstances.

[0117] Over the entire periphery of the first angular alignment sector 20A, a vertical operating clearance is reserved between the railing 52 and the peripheral plate 34. This vertical clearance allows the rotation of the peripheral plate 34, but it is nevertheless sufficiently small to allow the railing 52 to retain the entire preform 12 inside the centrifuge bowl 20. This vertical clearance is thus less than the minimum diameter "D3" of the body 14 of the preform 12.

[0118] As shown in , on this alignment sector 20A, the railing 52 here extends vertically above the peripheral plate 34, so that the circular outer edge 26 of the peripheral plate 34 is arranged outside the centrifuge bowl 20. However, the inner edge 36 of the peripheral plate 34 is located inside the centrifuge bowl 20 so that preforms 12 arranged against the railing 52 are entirely supported by the peripheral plate 34.

[0119] During operation of the alignment and straightening device 10, as shown in Figures 7 and 8, during a first discharge step, the preforms 12 discharged in bulk by the spillway 54 are projected radially against a receiving portion 52A of the railing 52 under the combined effect of their radial sliding speed at the outlet of the spillway 54 and the centrifugal force produced by the rotation of the central plate 28. At the same time, the central plate 28 also begins to drive the preforms 12 tangentially downstream in its rotation.

[0120] During a second alignment step, the preforms 12 are held inside the centrifuge bowl 20 by the railing 52, then, after one or more rebounds against the railing 52, they are fully supported by the peripheral plate 34. They are then constantly held radially against the railing 52 by the centrifugal force produced by the rotation of the peripheral plate 34 as well as by the conveying force produced by friction of each preform 12 against the peripheral plate 34 which pushes the preforms 12 tangentially against the railing 52. The path followed by the same preform 12 is shown from its arrival via the spillway 54 to its stable position against the railing 52. The preforms 12 are driven in purely tangential movement by the peripheral plate 34 in a positive direction along the railing 52.

[0121] In this configuration, the preforms 12 naturally occupy the most stable position in which their main axis "A" is oriented in a direction tangent to the central plate 28.

[0122] Most of the preforms 12 present in the angular alignment sector 20A of the centrifuge bowl 20 are thus aligned tangentially against the railing 52, their main axis "A" being oriented substantially tangentially to their direction of movement. The tangential gap between two successive correctly aligned preforms 12 is random because the central plate 28 is perfectly smooth and does not have any notches for indexing the preforms 12. The preforms 12 can thus be in contact by their ends under the effect of the centrifugal force which forces the preforms 12 to slide relative to each other. The preforms 12 thus optimally occupy the entire peripheral length of the centrifuge bowl 20.

[0123] The fact that the preforms 12 are held on the peripheral plate 34 makes it possible to keep them pressed radially against the railing 52. Thus, the preforms 12 are guided in a stable manner by the railing 52 during their movement around the centrifuge bowl 20.

[0124] At this stage, the preforms 12 are randomly oriented neck 16 upstream or downstream without impact on the rest of the process. The preforms 12 thus aligned continue their peripheral movement in the straightening sector 20B under the effect of the rotation of the peripheral plate 34, independently of the rotation speed of the central plate 28.

[0125] As shown in the, on the second angular sector 20B for straightening the centrifuge bowl 20, the centrifuge bowl 20 has a peripheral gap 56 delimited radially between the railing 52 and the circular outer edge 26 of the peripheral plate 34. The radial width of the gap 56 is between the maximum diameter "D2" of the body 14 and the outer diameter "D1" of the support face 18, in this case the collar. This gap 56 extends to the exit passage 53 of the preforms 12.

[0126] At least along the entire length of the second straightening sector 20B, the railing 52 has a rail 58 for supporting the support face 18. The rail 58 projects radially inward at the same level as the upper face of the peripheral plate 34 to delimit the gap 56 outwardly. The rail 58 extends here to the exit passage 53.

[0127] Thus, the preforms 12 are capable of being supported by their support face 18, in this case by their collar, which rests at two diametrically opposite points on the horizontal upper face of the peripheral plate 34, on the one hand, and on a horizontal upper face of the rail 58, on the other hand, the body 14 of the preforms 12 being below the level of the peripheral plate 34 through said gap 56. The two support points are radially aligned. The rail 58 makes it possible to support the preforms 12 in a stable manner.

[0128] Thus, during a third straightening step, as shown in Figures 10 and 11, the preforms 12 aligned during the second step arrive from the first alignment sector 20A by being aligned on the peripheral plate 34 in an elongated position in a row along the railing 52, their main axis "A" oriented tangentially. The aligned preforms 12 are randomly arranged neck 16 upstream or neck 16 downstream without this having any influence on their straightening.

[0129] When the body 14 of each preform 12 reaches above the gap 56, the body 14 begins to fall, as shown in Figures 12 and 13, thus tilting the preform 12 about a radial axis passing through the support points of the support face 18, in this case the collar, of the preform 12. The tilting continues until the main axis "A" of the preform 12 is vertical, possibly after a few swings about the radial axis. The preform 12 is then supported by its support face 18 resting jointly on the rail 58 and on the peripheral plate 34, as shown in Figures 14 and 15. The preform 12 is thus straightened, neck 16 at the top. The preform 12 thus correctly positioned is guided externally by the rail 58 of the guardrail 52, and it is guided internally by the circular external edge 26 of the peripheral plate 34.

[0130] During tilting, the main axis "A" of the preform 12 remains in a vertical plane tangent to the movement. Due to the tilting of the main axis "A" in the direction of movement of the preforms 12, the support face 18 of each preform 12 remains permanently in contact with the peripheral plate 34 on the one hand, and the rail 58 on the other hand, by its two support points. Thus, each preform 12 is guided in a stable and efficient manner during its straightening.

[0131] As shown in , a transition zone is provided at the upstream end of the angular straightening sector 20B. In this transition zone, the gap 56 is gradually widened until it reaches its final width. To do this, the guardrail 52 gradually moves radially away from the axis "B" of rotation of the central plate 28. This allows the aligned preforms 12 to remain constantly in contact with the guardrail 52 under the effect of centrifugal force. The preforms 12 are thus guided stably in the aligned position even during their straightening.

[0132] If the guardrail 52 had a discontinuity, it could no longer fulfill its guiding role at the level of this discontinuity. The aligned preforms 12 would then risk jumping or finding themselves badly positioned, for example coming to bear at an angle against adjacent preforms 12 and preventing them from straightening.

[0133] The correctly positioned preforms 12, that is to say thus aligned and straightened, are rotated about their main axis by friction against the circular outer edge 26 of the peripheral plate 34. The correctly positioned preforms 12 are moved to the periphery of the centrifuge bowl 20 in the direction of rotation of the peripheral plate 34 by rolling against the peripheral railing 52.

[0134] To improve this phenomenon of rolling of the correctly positioned preforms 12 and thus increase their speed of advance around the peripheral plate 34, the circular outer edge 26 of the peripheral plate 34 advantageously comprises a rolling strip 60 which has a coefficient of friction adapted to allow rolling without sliding of the body 14 of the preform 12 against the rolling strip 60. Such an arrangement is for example shown in Figures 4 and 9.

[0135] The correctly positioned preforms 12 are thus conveyed to the third outlet sector 20C. The third outlet sector 20C comprises a peripheral zone which is protected by a fixed deflector 62 which is arranged above the central plate 28 and the peripheral plate 34 at a vertical distance less than that of the minimum diameter "D3" of the body 14 of the preforms 12 to prevent incorrectly positioned preforms from coming into contact with the line of correctly positioned preforms 12 in the gap 56. As shown in , the deflector 62 extends in a spiral arm from an upstream end 62A which is arranged at the level of the circular outer edge 26 of the peripheral plate 34, to a downstream end 62B arranged near the center of the central plate 28 downstream of the outlet passage 53.The upstream end 62A of the deflector 62 is radially spaced from the railing 52 so as to reserve sufficient passage to allow the correctly positioned preforms 12 to pass.

[0136] The deflector 62 thus ensures that in the protected zone located between the downstream face of the deflector 62 and the railing 52, no incorrectly positioned preform 12 is lying on the peripheral plate 34.

[0137] It is also understood that it is possible to equip the centrifuge bowl 20 with other means for sorting incorrectly positioned preforms 12 such as the primary and / or secondary untangling wheels described in application FR 3,035,090 A1.

[0138] A primary untangling wheel 64 is shown comprising paddles mounted on a rotor. It is possible to re-dispatch the incorrectly positioned preforms 12 to the angular alignment sector 20A, for preforms 12 of various formats and for very high preform 12 throughputs. The method also makes it possible to avoid damaging preforms 12 and / or elements of the alignment and straightening device 10.

[0139] It is intended to be possible to straighten and align batches of preforms 12 of different dimensions. In order to be able to adapt the width of the gap 56 to the dimensions of the preforms 12, the peripheral plate 34 is here fixed in a removable manner on the orientation ring 38. Each angular segment 34A, 34B, 34C of the peripheral plate 34 is for example fixed by means of screws or by means of quick fasteners such as clamping clamps.

[0140] By way of non-limiting example, the peripheral plate 34 here comprises an inner ring 34-1 and an outer ring 34-2. The outer ring 34-2 is fixed in a removable manner to the inner ring 34-1, for example by means of radial screws (not shown). Thus, it is possible to keep the inner ring 34-1 for all dimensions of preforms 12, while the outer ring 34-2 can be replaced by an inner ring 34-1 having a different outer diameter to adjust the width of the gap 56 according to the dimensions of the preforms 12 to be straightened.

[0141] The outer 34-2 crown is then fitted with the 60 tread.

[0142] When using the alignment and straightening device 10, the centrifugation speed V1 of the central plate 28 is controlled according to the centrifugal force required according to the weight of the preforms 12 to be aligned. The centrifugation speed V1 of the central plate 28 is generally a constant, but it can also be decreased or increased depending on the quantity of preforms 12 present in the centrifuge bowl 20.

[0143] The conveying speed V2 of the peripheral plate 34 is controlled as a function of the required displacement speed for the preforms 12 around the centrifuge bowl 20. This conveying speed V2 of the peripheral plate 34 may be equal to that of the central plate 28. However, due to the presence of two independent motors 32, 46, the conveying speed V2 of the peripheral plate 34 may also be different from that of the central plate 28. This conveying speed V2 may be increased or decreased as a function of various parameters including, but not limited to:

[0144] - the quantity of preforms 12 present in the centrifuge bowl 20, and / or

[0145] - the flow rate of preforms 12 required by the installation, and / or

[0146] - the detection of preforms 12 blocked in the centrifuge bowl 20.

[0147] The centrifugation speed V1 of the central plate 28 is generally always positive, while the conveying speed V2 of the peripheral plate 34 can occasionally be negative, in particular during blockages of preforms 12.

[0148] The alignment and straightening device 10 produced according to the teachings of the invention very advantageously makes it possible to independently control:

[0149] - the centrifugal force applied to the preforms 12 poured in bulk into the centrifuge bowl 20 by controlling only the centrifugation speed V1 of the central plate 28, and

[0150] - the speed of movement of the preforms 12 aligned on the periphery of the centrifuge bowl 20 by controlling only the speed V2 of conveying the peripheral plate 34.

[0151] To further improve these functions, the upper face of the central plate 28 may have a coefficient of friction with the preforms lower than the coefficient of friction of the upper face of the peripheral plate 34. Thus, the preforms 12 will slide more easily on the central plate 28 under the effect of centrifugal force, while they will be held more stably on the peripheral plate 34 once aligned.

[0152] This makes it possible to better regulate the flow of preforms 12 leaving the alignment and straightening device 10 while maintaining good alignment by centrifugation of the preforms 12.

[0153] Furthermore, the presence of the peripheral plate 34 around the central plate 28 makes it possible to obtain a gap 56 having a better controlled width than in the prior art. Indeed, in the prior art, the bottom was formed by a single large plate. Due to manufacturing tolerances, the diameter of the single plate was obtained with an uncertainty of several tenths of a millimeter, for example six tenths of a millimeter. This uncertainty had an influence on the width of the gap 56 and this therefore required processing preforms 12 having a support face 18 having a radial width of more than 2 mm. By producing the bottom 24 in several plates 28, 34, it is possible to obtain a gap 56 of more precise width allowing the processing of preforms 12 having a support face 18 of radial width less than 2 mm.The gain in precision comes from the much reduced radial width of the peripheral plate 34 and the possibility of absorbing part of the dimensional disparities in the radial clearance "j" reserved between the central plate 28 and the peripheral plate 34.

Claims

Device (10) for aligning in a row and straightening preforms which comprises a centrifuge bowl (20) comprising:- a horizontal circular central plate (28) rotating about a vertical axis (B) of which an upper face is intended to receive loose preforms;- a fixed peripheral railing (52) which extends vertically projecting above the upper face of the central plate (28) and against which the preforms (12) are intended to be projected and aligned by centrifugation during the rotation of the central plate (28);- a peripheral gap (56) which extends at least along an angular sector (20B) for straightening the preforms (12) to allow the straightening of preforms (12) aligned along the railing (52) by tilting a body (14) of the preforms (12) in the gap (56) while the neck (16) is supported above the level of the upper face of the central plate (28);characterized in that it comprises an annular peripheral plate (34) which is mounted to rotate around the central plate (28) independently of the central plate (28), the gap (56) being delimited between the railing (52) and a circular outer edge (26) of the peripheral plate (34) and in that the peripheral plate (34) and the central plate (28) are mounted to rotate coaxially around the vertical axis (B).; Device (10) according to the preceding claim, characterized in that the central plate (28) is driven by a rotation speed (V1) which is controlled as a function of the centrifugal force required according to the weight of the preforms (12) to be aligned and the peripheral plate (34) is driven by a rotation speed (V2) which is controlled as a function of the speed of movement required for the preforms (12) around the centrifuge bowl (20). Device (10) according to any one of the preceding claims, characterized in that the central plate (28) has a flat upper face orthogonal to the vertical axis (B). Device (10) according to any one of claims 1 or 2, characterized in that the central plate (28) has an upper convex face axisymmetrical with respect to the vertical axis (B). Device (10) according to any one of the preceding claims, characterized in that the peripheral plate (34) has an upper face which is coplanar with a peripheral edge (29) of the upper face of the central plate (28). Device (10) according to any one of the preceding claims, characterized in that the peripheral plate (34) is arranged around the central plate (28) with reservation of a radial clearance (j) allowing its independent rotation. Device (10) according to the preceding claim, characterized in that the radial clearance (j) is less than 2 mm, preferably less than 1 mm. Device (10) according to any one of the preceding claims, characterized in that the central plate (28) is driven in rotation by a first motor (32), while the peripheral plate (34) is driven in rotation by a second motor (46). Device (10) according to any one of the preceding claims, characterized in that the peripheral plate (34) is mounted on an orientation ring (38). Device (10) according to any one of the preceding claims, characterized in that the peripheral plate (34) is made of several angular segments (34A, 34B, 34C). Device (10) according to any one of the preceding claims, characterized in that the peripheral plate (34) comprises an inner crown (34-1) and a removable outer crown (34-2) to allow the width of the gap (56) to be adjusted according to the dimensions of the preforms (12) to be straightened. Method for controlling the device (10) according to any one of the preceding claims, characterized in that the speed (V1) of rotation of the central plate (28) is controlled as a function of the centrifugal force required according to the weight of the preforms (12) to be aligned, while the speed (V2) of rotation of the peripheral plate (34) is controlled as a function of the speed of movement required for the preforms (12) around the centrifuge bowl (20).

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