MXPA99011040A - Nozzle for blow moulding plastic containers and installation provided with same - Google Patents

Abstract

The invention concerns a nozzle (1) for blow moulding containers from blanks (21) comprising a neck (32) characterised in that it comprises an orifice (3) supplying blowing fluid into the blank whereof the dimensions are such that the orifice covers the neck when the blank is set in a blow mould (17).

Description

MOLDING NOZZLE BY BLOWING PLASTIC AND INSTALLATION MATERIAL CONTAINERS PROVIDED WITH TAL NOZZLE Description of the invention The invention relates to the improvements made to the machines for manufacturing containers, such as bottles or bottles, made of plastic material, by blowing primordia or blank pieces such as preforms, or intermediate containers obtained at the time of a previous phase of transformation of plastic material. This relates more particularly to the organs, so-called blowing nozzles, which equip these machines. It is now well known to manufacture plastic containers by blowing primordia or rough pieces of plastic material. When the primordium is a preform, it is obtained either by injection of the plastic material in an injection and forming mold, or by extrusion by blowing the plastic material into a forming mold. The preform suffers immediately an appropriate thermal treatment, more or less sophisticated according to the characteristics of the container to be obtained, and / or is placed in a finishing mold, which contains the impression of the container to be obtained. A blowing nozzle is then introduced into the opening (the neck) of the preform and a blowing fluid, usually of air under high pressure, is injected into the preform to blow it and to place the material longitudinally to the walls of the mold, allowing to obtain the recipient. Preferably, mainly in the machines of the applicant that produce containers from previously injected preforms, the blowing is preceded or accompanied by stretching (or lengthening) of the preform with the help of an extension pin. Preferably, when the stretch precedes the blowing with the help of high pressure air, this is accompanied by a pre-blowing with the help of air at a very low pressure, to avoid mainly that, at the time of stretching, the material is not encased on the spike. When the blank is an intermediate container, it is generally obtained from a first container, obtained by blowing a preform in a first mold. The first container, after its exit from the first mold, undergoes a particular treatment, typically thermal, immediately after which the intermediate container is obtained which is then placed in a second mold in which the intermediate container is transformed into the final container by means of injection of a blowing fluid, with the help of a nozzle identical to that described above. The European patents granted under numbers 237459 and 442836, in the name of the applicant, describe two variants of equipment that make it possible to obtain a first container from a preform subsequently injected, then the transformation of the first container into the intermediate container, in order to obtain a final container with good mechanical properties, mainly at the time of hot filling or with the help of carbonated or carbonated drinks. Typically, the processes and equipment of the last indicated type need in step through a phase of obtaining a single intermediate container. The obtaining of several successive intermediate containers before obtaining the final container can be considered very well.

The molds used for the manufacture of the final containers, or each mold to obtain a container from which an intermediate container is obtained, are generally in at least two parts, separable or approachable one to the other. Each part includes a semi-impression of the container to be obtained (background, wall, shoulder). However, preferably, the known molds include three parts: a part with the impression of the bottom of the container and two parts to constitute the walls and the shoulder of the container. This preferred structure facilitates unmolding when the bottom of the container has certain types of reliefs (mainly petaloid bottoms). The parts are separated (separated) one from the other at the time of putting the rough piece in its place, and at the moment of the expulsion of the container. These are approached, and the mold closes at the moment of the blowing phases (with or without stretching and / or pre-blowing). A disadvantage of the equipment or machines for manufacturing containers (intermediate or end) refers to the structure of the blowing nozzles that are employed here.

It is known that the neck, even called neck, of the final container is generally obtained at the time of manufacture of the preform. When the latter is transformed into a container, either immediately final or intermediate, the dimensions of the neck should not be modified or only very little modified. Similarly, consequently, the neck dimensions of the intermediate container should not, or should vary little and the final container must therefore have a neck identical to that of the preform. In effect, the neck includes either roses to receive a plug, or a reinforced edge to receive a crimped capsule or plug. It is therefore very difficult to control the deformation of the neck after the formation of the preform, and it is preferable to keep it in that state after the successive transformations. That is why, at the time of the stages of transformation of the preform in the final container or intermediary, and in this last case, of an intermediate container in another container (intermediate or even final), the neck is supported on the outside of the container. mold and is not modified by blowing. The nozzle is constituted by a tube whose blowing end (nose of the nozzle) is encased to be able to be inserted in the opening of the blank. Typically, the end of the nozzle is of frustoconical section. The diameter at the base of the trunk of the cone, therefore that of the nozzle, is lower than that of the opening. Consequently, when the nozzle is introduced into the neck, a contact between the truncated base of the cone and the peripheral peripheral edge of the blank becomes established, ensuring the tightness at the time of blowing, and the maintenance of the force of the rough piece in good position in relation to the mold. But this type of nozzle is not fully adapted for the following reasons: under the strong pressures necessary for blowing (typically 40 bars in the machines of the applicant), it is necessary to exert a significant pressure of support between the nozzle and the piece in rough to avoid leaks. It is therefore necessary to ensure that the neck has a thickness of material that is sufficiently important to give it sufficient rigidity so that it does not deform through the nozzle at the moment of support. However, the sale price of a container is largely linked to the cost of the material. A trend that has existed for some time, is to obtain pieces in coarse with light neck to reduce the selling price, but there is a lower limit from which the mouthpiece causes a burst of the neck; - the same equipment can be used to manufacture series of different containers. The user is therefore led to modify the personalization of his team. If the height of the neck is modified and / or if the diameter of the neck is modified, the regulation of the course of the mouthpiece and / or the change of the mouthpiece must be modified. Whence a loss of time, and even an extra cost for the team; these nozzles are ill-adapted to the blowing of sterile or aseptic containers, with the help of a sterilizing or aseptic fluid, since the contact zone between the interior of the beverage and the nozzle, if this has not been aseptized or sterilized before blowing , it remains in that state: the septic or anti-sterile particles risk getting to contaminate the interior; when a lengthening pin is present, which is the rule, it slides axially into a cylindrical hole provided in the nozzle, and oriented according to the longitudinal axis of the latter, and an annular space is left free around the pin to allow the passage of blowing fluid around the pin in this hole. But the section of this space is necessarily limited, in such a way that the passage of fluid is slowed down. The object of the invention is to remedy these drawbacks. According to the invention, a blowing nozzle, to provide blowing fluid to the interior of a piece of coarse material supported on its neck in a blow mold, in such a way that the neck emerges from the mold, the nozzle comprising a hole for supplying fluid in the piece in rough, it is characterized in that the hole has dimensions such that, when a blank is placed in the mold and the nozzle is in the blowing position, the hole covers the neck, and the peripheral edge of the hole, in front of the piece in coarse constituting the nose of the nozzle, which is placed in support on the mold, and the sealing means are provided at the level of this support. The nozzle according to the invention thus allows to avoid all the above-mentioned problems: • there is no more direct support on the preform to ensure the airtightness, in such a way that lightened necks can be used; • Problems related to personalization are solved: it is sufficient to calibrate the hole, so that it can contain collars larger than those that the machine is designed to treat; • since the blowing fluid reaches around the neck, the problems related to asepsis or sterilization are solved: the blowing fluid thus reaches around the neck, so that not only the inside of the container, but also the outside of the neck, it is clean; • In spite of the presence of a lengthening pin, a larger section is provided for passage to the blowing fluid, since the nose of the nozzle is not inside, but is on the outside of the neck, from where it is located. get a better blowing efficiency.

In a first variant, the sealing means are fixed at the nose end of the nozzle. In a second variant, the sealing means are fixed on the mold of the installation to which the nozzle is associated. Other features and advantages of the invention will appear on reading the following description, made with respect to the attached figures, in which: Figure 1 is a schematic sectional view of an installation part using a first variant of the nozzle, when the nozzle is not in the blowing position; Figure 2 is a sectional view, corresponding to the first variant, when the nozzle is in the blowing position; Figure 3 is a simplified top view of a mold, in closed position, usable with this first variant; Figure 4 is a schematic sectional view of an installation part using a second variant of the nozzle, when the nozzle is not in the blowing position; Figure 5 is a sectional view, corresponding to the second variant, when the nozzle is in the blowing position.

Figure 6 is a simplified top view, of a mold, in closed position, usable with the second variant.

In figures 1 and 2 a first embodiment of a nozzle according to the invention is represented, and the part of the blowing equipment to which it can be associated. The nozzle, designated as a whole by reference 1, has a body 2 in the form of a sleeve that is substantially cylindrical, perforated, over its entire length, of a coaxial hole made up of two holes 3, 4 coaxial to the axis 5 of the nozzle, and who communicate with each other by a first of their extremes.

According to the invention, a first one of these holes constitutes the fluid inlet hole in a blank when the nozzle is in place on a blower as will be described later. In the embodiment illustrated in FIGS. 1 and 2, a lever joint 6 is fixed around the second end of the first hole 3 and emerges axially, constituting in fact the nose 7 of the nozzle. The function of this gasket 6 is to ensure the airtightness at the time of blowing, as will be explained later. The gasket 6 is maintained around the second end of the first hole 3 provided in the body 2 of the nozzle, for example with the aid of a maintenance ring 8, screwed around said end. Preferably, the vents 9, 10 whose function will be explained later pass radially through the thickness of the ring 8. These vents are preferably distributed regularly around the ring 8 and open to the inner side thereof, at the level of the support plane 11 between the body 2 of the nozzle and the end of the gasket 6 opposite it which in fact constitutes the nose 7 of the nozzle. In a known manner, the nozzle 1 is fixed, by its opposite side to that where the first hole 3 is provided, to a jack 12 of the nozzle. More precisely, the body 2 is made integral with a shaft 13 associated with a piston 14 sliding on a cylinder 15, the piston assembly, cylinder, and the axle constituting the jack. Preferably, as illustrated in these figures 1 and 2, the body 2 of the nozzle is screwed to the end of the shaft 13. For this purpose the second hole 14 provided in the body 2 is threaded and the end of the shaft 13 is threaded from corresponding way. The jack is double acting: for this purpose, a first hole 16 provided at one end of the cylinder 15 allows the piston to be dragged and thus the nozzle 1 towards the mold 17 and a second hole 18 allows the nozzle to move away from the mold. In a known manner, the assembly constituted by the piston 14 and the axis 13 that extends it is perforated over its entire length, from a tubular hole 19, coaxial to the axis 5 of symmetry of the nozzle 1 and of the jack 12.

A pin 20 for elongation of the associated blank piece 21 is placed in this hole. The internal diameter of the hole 19 is greater than the external diameter of the pin or rod 20, in such a way that an annular space 22 is provided on the periphery of the pin 20, allowing the passage of the pre-blowing and / or blowing fluid towards the first hole 3 of the nozzle 1, and then towards the blank 21, with a view to realizing the desired container in the mold 17. The annular space 22 is put in communication with a conduit 23 for supplying the fluid under pressure, for the pre-blowing and / or blowing. This conduit 23 is, in a known manner, connected to one or more sources of fluid supply. The pin 20 can slide relatively in the assembly constituted by the cylinder 15 on the one hand, and the subassembly of the piston 14, axis 13, nozzle 1. The known displacement means of the pin are not represented: it can be another jack, and / or a mechanism of cams and rollers, or any other appropriate means. In a known manner, the guide bearings 24, 25 of the pin 20 are respectively provided on the end of the cylinder 15 and on the junction between the axis 13 and the nozzle 1. On the other hand, at least the guide on the end of the cylinder It is hermetic. For this, either the bearing 24 is airtight or, preferably, this is completed by a gasket 26. The leakage at this level is intended to prevent any leakage of blowing fluid around the spigot 20. The guide bearing 25 in the connection between the shaft 13 and the nozzle 1 is for example constituted by a ring inserted in a corresponding cavity 27, provided at the end of the shaft 13, and held in place by the nozzle, when it is mounted on the shaft 13. The ring is also perforated over its entire height with at least two holes 28, 29 which each communicate with the annular space 22 and the first hole 3 of the nozzle 1, so that the blowing fluid can circulate from the duct of supply 23 towards the nose of the nozzle. Of course, the attachment of the nozzle on the shaft 13 is tightly secured, either by a sufficient tightening of the nozzle 1 on the shaft 13, or with the aid of added means such as gaskets or any other known device ( sealing rubber, joint paste, tow, etc.). In Figure 1, the nozzle 1 and the extension pin 20 are shown in the raised or raised position (in the case where the mold is located under the nozzle). The nozzle is thus far from the blank 21, and the tang 20 is erased in the nozzle. The blank 21, here a preform, is in place in the mold 17 containing the impression 30 of the container to be obtained. In Figure 2, the nozzle is in the blowing position. The nose 7 of the nozzle, more precisely the gasket 6 constituting it, is in abutment on the upper flange 31 of the mold, and the spigot 20 is represented in a position according to which its free end is in support in the bottom of the preform, ie in a position preceding immediately to the stretching of the preform. This figure shows that the dimensions of the first hole 3 of the nozzle 1 are such that the neck 32 of the blank 21 is contained, ie covers, in this hole. Preferably, and in a known manner, the upper flange part 31 of the mold 17 on which the gasket 6 rests is a ring, consisting of two half-rings 33, 34 facing each other at the level of the joint plane 35 between the two half-molds 36, 37. This ring is a piece that can be changed. The function of the vents 9, 10 in proximity of the nose 7 of the nozzle is to avoid, when the nozzle is moved away (traced) from the mold after blowing, while still being fluid under pressure, that the joint 6 does not deteriorate. In the absence of these vents, the lever of the joint 6 would have the tendency to be expelled towards the outside at the beginning of the elevation due to the fact of the strong pressure that prevails in the nozzle. With the vents, since the nozzle starts to move away from the mold 17, the seal is no longer strongly plated against the neck ring 33, 34. Indeed, due to the pressure that prevails inside, the inner peripheral surface of the joint has the tendency to depart from the area on which it is in support in the body 2 of the nozzle, which involves the appearance of a gap between the joint and the body of the nozzle, allowing a part of the fluid to escape through this gap in the direction of the vents, and then to the outside. In figures 4 and 5 a variant of the nozzle is represented; Figure 6 shows how the mold must be adapted to cooperate with this variant. The nozzle shown on this variant differs from that represented on FIGS. 1 and 2 only by the means for ensuring the airtightness between the nose 7 of the nozzle and the mold. Also, the same elements carry the same reference numbers and are sent again to the description of figures 1 and 2 for the part that concerns them. The nozzle 1 includes a body 2 pierced by two holes 3 and 4. A first 3 of these holes will be for covering the neck 38 of a blank piece 39, here a narrowed body intermediate container as described in European Patent No 442 836 in the name of the applicant. The second threaded hole 4 is screwed onto a corresponding tapping of an axle 13 attached to the piston 14, and an extension pin 20 is displaced in the jack 12.

The difference between this nozzle and that described in figures 1 and 2, in fact tries that the nose 7 of the nozzle is not constituted by a joint, but rather by the rim 40 of the opening of the first hole 3 towards the outside, the first hole being then completely made in the mass of the body 2. The tightness is ensured, at the moment in which the nozzle (Figure 5) is placed by a joint 41 consisting of two portions 42, 43 of semicircular joints, respectively arranged in the upper wall 44, 45 of each of the half-molds 46, 47 or, preferably, in the neck ring, consisting of two half-rings 48, 49 placed respectively on each of the half-molds, when this ring is present (figure 6) ). An advantage of this variant is that the joint more easily takes its place and is not ejected after the nozzle elevations. It has been found, surprisingly, that a nozzle according to the invention requires no more than the blank 21, 39 to be firmly adhered against the mold, at the level of the neck ring at the time of blowing. It is therefore entirely possible to make containers without using the extension pin 20 which, when it is in place, keeps the blank in the mold. Even when the spike is not used, the rough piece does not vibrate under the effect of the fluid and it does not escape to the inside of the mold, on the outside of the piece in rough. The fluid is directed into the interior of the blank without particular problems. It is well understood that the invention is not limited to the embodiments described. In particular, the attachment of the nozzle to the jack could be ensured in any other way than by means of a threaded hole 4 and a corresponding tapping on the axle 13 of the jack; similarly, the lengthening pin 20 could not be present, the latter not being more than an accessory not of the nozzle, but of the installation itself.

Claims (13)

1. A blowing nozzle to provide blowing fluid to the interior of a blank or blank, supported under its neck in a blow mold, such that the neck emerges from a wall of the mold, the nozzle includes an orifice assortment of fluid in the blank, characterized in that the hole has dimensions such that, when the blank is placed in a mold and the nozzle is in the blowing position, the hole covers the neck, and the peripheral rim of the hole, in front of the piece in rough, constituting the nose of the nozzle, which is placed on the mold wall, and sealing means that are provided at the level of the support area.

2. The nozzle according to claim 1, characterized in that the sealing means are constituted by a seal that surrounds the nose of the nozzle.

3. The nozzle according to claim 2, characterized in that the seal is held on one end of the body of the nozzle by a clamping collar.

4. The nozzle according to claim 3, characterized in that the collar is screwed around the end of the body.

5. The nozzle according to any of claims 3 or 4, characterized in that the collar is provided with at least one vent passing through its thickness and which opens into the level of the bearing plane between the joint and the end of the body.

6. The installation for blowing containers from coarse pieces, characterized in that it includes a nozzle according to any of claims 1 to 5.

7. The installation for blowing containers from coarse pieces, characterized in that it includes a nozzle according to claim 1 and the sealing means are constituted by a joint supported by the wall of the mold from which the neck emerges and which surrounds said neck .

8. The blowing installation according to claim 7, characterized in that the mold is constituted by two half-molds, the joint is constituted by two portions each carried by a half-mold respectively.

9. The installation according to any of the preceding claims 6 to 8, characterized in that the first orifice of the nozzle is brought into communication with a fluid assortment line.

10. The installation according to claim 9, characterized in that the nozzle is associated with a jack of the nozzle carried by the installation, and communications are carried out on the jack.

11. The installation according to any of claims 6 to 10, characterized in that it includes a pin for elongation of the blank, which passes through the first hole and can slide relative to it.

12. The installation according to claim 10, characterized in that the nozzle is fixed on a jack axis, said shaft being connected to a piston that slides in a cylinder carried by the installation.

13. The installation according to claim 12, characterized in that the nozzle is fixed to the shaft by screwing and includes to make this a second threaded hole, and the shaft is correspondingly tapped.