Device for injecting at least two pressurized fluids into the neck of a container in order to form said container

A device (24) for injecting at least two pressurized fluids into the axially oriented neck (20) of a container (18) in the preform state in order to form a final container by deforming the container (18) by successively injecting a first pressurized fluid and then a second pressurized fluid, the device (24) including: a first duct for supplying a first pressurized fluid; a second duct (30) for supplying a second pressurized fluid; and an axial nozzle (32) into which the second supply duct (30) opens, the nozzle being intended to be placed concentrically inside the neck (20) with a radial gap (j) so as to allow the first pressurized fluid to be injected into the container (18) through the radial gap (j), characterized in that the second pressurized fluid used for forming the container (18) consists of an incompressible filling liquid.

The invention relates to a device for injecting at least two pressurized fluids into the neck of a preform.

The invention relates more particularly to a device for injecting at least two pressurized fluids into the axially oriented neck of a container in the parison state for forming a final container by deforming said container by the successive injection of a first pressurized fluid then of a second pressurized fluid, the device comprising:a first supply pipe supplying a first pressurized fluid;a second supply pipe supplying a second pressurized fluid.

Thermoplastic containers such as bottles, vials, etc. are manufactured by forming containers in the parison state, which are sometimes known as preforms.

Prior to implementing the forming method, the containers in the parison state are heated in a thermal conditioning oven to confer upon them a structure that is malleable enough to support the forming method.

These containers in the parison state are then introduced into a molding unit with which blow-molding or stretch-blow-molding means are generally combined.

At the end of the forming method, a filling step is carried out. During this filling step, the container in the final state is generally filled with a liquid which is intended to be marketed or transported in the final container.

Document EP-A-2 143 544 has proposed modifying the forming method by using a liquid to finalize the shaping of the container. The method according to this prior art thus comprises a first step of partial expansion of the container from its parison state to an intermediate state by blowing in a low-pressure blow-molding gas, then a second step of filling the container in said intermediate state with a filling liquid, and finally a third state of shape adoption during which the liquid contained in the container is raised to a high pressure in order to confer the final shape upon the container.

The filling liquid is generally incompressible in relation to a gas. This therefore allows for a rapid and effective increase in pressure.

Advantageously, the liquid used during the third step of shape adoption is the liquid that is intended to be transported in the container in the final state. Such a method thus allows the container to be filled with the liquid during the forming method. This notably allows time to be saved by avoiding the need to add a filling operation after the forming method.

It is an object of the present invention to provide a device for injecting blow-molding gas and filling liquid that is more rapid and works better, so as to produce final containers of better quality.

To this end, the invention proposes an injection device of the type described hereinabove, characterized in that the second supply pipe opens into an axial nozzle which is intended to be arranged concentrically inside the neck with a first radial gap so as to allow the first pressurized fluid to pass between the container and the first supply pipe through the first radial gap.

According to other features of the invention:the first supply pipe opens into a bell surrounding the neck of the preform in a fluidtight manner;the device comprises a sealing mechanism that can be made to switch between an open position in which the first fluid is able to pass through the first radial gap, and a closed position in which a seal plugs the first radial gap between the nozzle and the neck of the container in a fluidtight manner;the seal can be interposed radially in the first radial gap between the nozzle and the internal wall of the neck;the seal is of annular shape and is arranged externally around the nozzle, the seal being elastically deformable between a contracted state in which the first fluid can pass toward the inside of the container via a second radial space left between the seal and the internal wall of the neck, and an expanded state in which the seal is radially pressed firmly against the internal wall of the neck of the container in order to plug the first radial space in a fluidtight manner;the expansion of the seal is brought about by the relative axial sliding of a conical annular wedge of axial axis with respect to the seal;the annular seal is mounted to slide axially with respect to the nozzle between a raised retracted position in which the seal is arranged vertically above the neck; and a lowered position of insertion in the first radial gap into the neck, in which position the seal is interposed radially between the nozzle and the neck;the conical wedge is carried by the external wall of the nozzle which is mounted to slide axially with respect to the seal so as to cause the seal to switch into its expanded state when the seal is in its lowered position of insertion;the wedge is formed as an integral part of the nozzle;the sliding of the nozzle is brought about by a piston able to move axially in a cylinder;the first fluid consists of a compressible blow-molding gas such as compressed air;the second fluid consists of an incompressible filling liquid;the device is mounted to slide axially between an upper standby position in which it is arranged some distance above the neck of the container, and a lowered injection position in which the device is able to inject the first pressurized fluid and/or the second pressurized fluid.

For the remainder of the description, a bottom-up vertical orientation indicated by the arrow “V” of the figures and a radial orientation directed orthogonally outward from the axis “A” of the container will be adopted nonlimitingly.

For the remainder of the description, elements offering analogous, identical or similar functions will be denoted by the same reference numerals.

FIG. 1depicts a molding unit10that is capable of implementing a forming method comprising at least:a first step of blowing a first pressurized fluid, which in this instance is a compressible blow-molding gas such as air, thena second step of filling with a second pressurized fluid, which in this instance is an incompressible filling liquid, such as water, which is intended to be packaged in the container.

The molding unit10comprises a mold12which is generally produced in several parts that can be separated in order to insert and/or extract the container before and after the forming thereof.

Hereinafter, when reference is made to the mold12without any further specifics, it is to be understood that the mold12is in its assembled position.

The mold12in this instance is produced in two parts that can be separated from one another radially. Each part comprises a concave half-impression of the final container that is to be obtained (bottom, walls, shoulder). Thus, when the two parts are assembled to form the mold12, the two half-impressions form a cavity14delimited by an impression of the final shape of the container in the final state.

As an alternative, the molds comprise three parts: one part with the impression of the bottom of the container and two parts to form the walls and shoulder of the container.

The cavity14is open vertically upward via an upper orifice16formed in a horizontal upper face17of the mold12.

The mold12is intended to house a container18made of a thermoplastic material. Such a container18in the parison state is generally known as a preform. The container18in the parison state is thermally conditioned beforehand in order to render the thermoplastic material malleable enough for the container18to be able to be blow-molded, or expanded, to form a final container having the same shape as the cavity14, as depicted inFIG. 4.

The container18generally comprises a hollow body19which is open at the top via an orifice delimited radially by a neck20of vertical axis “A”, also known as the mouth.

In the known way, the neck20of the container18generally already has its definitive shape when the container18is in the parison state. The dimensions of the neck20must therefore not be altered during the forming method. To achieve this, only the body19of the container18in the parison state is housed in the cavity14of the mold12, the neck20extending outside the cavity14leaving it via the upper orifice16in order to avoid any chance deformation.

InFIGS. 1 and 2, the container18has been depicted in the parison state. InFIG. 3, the container18is depicted in an intermediate state. InFIG. 4, the container18is depicted in its final state. It will be understood that, during the forming of this container18into the final container, the neck20will maintain its initial shape.

The body19of the container18is separated from the neck20by a flange22which projects radially outward. The flange22in this instance keeps the neck20outside the cavity14of the mold12by resting against the upper face17of the mold12.

The molding unit10comprises a device24for injecting at least two pressurized fluids into the neck20of axial orientation of a container18in order to form a finished container by deforming said container18in the parison state during the successive injection of a first pressurized fluid and then of a second pressurized fluid.

In the figures, the injection device24depicted has overall symmetry of revolution about the axis “A” of the neck20.

As explained previously, the first fluid consists of a blow-molding gas such as compressed air at 10 bar, while the second fluid consists of an incompressible liquid, such as water, that can be compressed for example to a pressure of 40 bar.

The device24can be made to switch between:an upper standby position, as depicted inFIG. 1, in which it is arranged some distance above the upper face17of the mold12so as to allow a container18in the parison state to be introduced or a final container to be extracted;a lower injection position, as depicted inFIGS. 2 to 4, in which the device24can inject the pressurized blow-molding gas and/or the pressurized filling liquid.

The device24comprises at least one first supply pipe25which is connected to a controlled source (not depicted) of compressed air. The first supply pipe25opens into a bell26which can cover the neck20in a fluidtight manner when the nozzle24is in its lower position of injection.

The bell26is formed in a casing27of the device24.

The lower end edge of the bell26is equipped with a seal28which is intended to be clamped vertically downward against the upper face17of the mold12or against the flange22of the neck20. In the example depicted in the figures, this is a lip seal28which is intended to be pressed firmly against the upper face17of the mold12by the pressure of the compressed air with which the bell26can be supplied.

The device24further comprises a second supply pipe30which is connected to a controlled source (not depicted) of pressurized filling liquid. That part of the second supply pipe30which is formed in the casing27has an orientation of vertical axis “A”. The lower end of the second supply pipe30opens into an injection nozzle32of vertical axis coaxial with the axis “A” of the neck20of the container18.

The nozzle32has a cylindrical tubular shape open at the bottom.

The nozzle32is intended to be arranged concentrically inside the neck20when the device24is occupying its lower position of injection. The nozzle32has an outside diameter such that, in this lower position, there is a first annular radial gap “j1” surrounding the nozzle32and extending radially between the external cylindrical face of the nozzle32and the internal cylindrical face of the neck20. This first radial gap “j1” allows the inside of the container18to communicate with the bell26. Thus, the blow-molding gas is injected into and escapes from the container18through this first radial gap “j1”.

The injection device24also comprises a controlled sealing mechanism34which can be made to switch between an open position in which the blow-molding gas is able to pass through the first radial gap “j1” in order to enter or leave the container18, and a closed position in which a seal36plugs the first radial gap “j1” between the nozzle32and the neck20of the container18in a sealed manner.

This controlled sealing mechanism34is notably used to allow the pressure of the filling liquid contained in the container18to be raised to a high pressure higher than that of the blow-molding gas, for example 40 bar, without causing said filling liquid to escape to the bell26through the first radial gap “j1”. This notably makes it possible to keep the outside of the neck20in the dry in order to make it easier for the closure to be fitted to the final container18containing the filling liquid.

The annular seal36is arranged externally around the nozzle32. The seal36is elastically deformable between a contracted state as depicted inFIGS. 2 and 3, which corresponds to the open position of the sealing mechanism34, and an expanded state, as depicted inFIG. 4, in which the annular seal36is radially pressed firmly against the internal wall of the neck20of the container18in order to plug the first radial clearance “j1” in a sealed manner, and which corresponds to the closed position of the sealing mechanism34.

In its expanded state, the seal36applies an outward radial force to the internal wall of the neck20. This radial force is indicated by the arrow “F2” inFIG. 4. To maintain the integrity of the neck20, it is advantageous for the seal36to be arranged in the region of the flange22of the neck20. This is because the flange22forms a sort of rib which enhances the rigidity of the neck20at this point, thus avoiding any potential plastic deformation caused by the expansion of the seal36.

In the example depicted in the figures, the annular seal36is advantageously mounted such that it can slide axially with respect to the nozzle32between:a raised retracted position, as illustrated inFIG. 2, in which the seal36is arranged vertically above the neck20when the device24is in its lowered position of injection, so as not to reduce the bore section available for the passage of blow-molding gas through the first gap “j1”, whether this be in the direction of injection into the container18or in the direction of escape to the bell26;a lowered position of insertion into the first radial gap “j1” inside the neck20, as illustrated inFIGS. 3 and 4, in which the seal36is interposed radially between the nozzle32and the neck20.

Thus, when the seal36is in its raised retracted position, the flow rate of blow-molding gas through the first radial gap “j1” is not limited by the presence of the seal36.

The seal36is, for example, lowered into its lowered position of insertion when the container18is almost full, for example 80% full, so as to ensure that the first radial gap “j1” is plugged in a fluidtight manner when the container18is full of liquid.

When the seal36is in its lowered position of insertion in its contracted state, the first radial gap “j1” is reduced to a second annular radial gap “j2” that remains around the seal36between the seal36and the internal cylindrical face of the neck20so as to allow the blow-molding gas to finish escaping.

The second radial gap “j2” is, of course, smaller than the first radial gap “j1”. In this configuration, the flow rate of the blow-molding gas is limited by the presence of the seal36but escape of blow-molding gas remains possible. Thus, even when the seal36is in the lowered position of insertion, the sealing mechanism24is in an open position.

Further, the fact that the seal36can be made to slide vertically in its contracted state, makes it possible to prevent the seal36from touching the neck20as it moves. Thus, neither the neck20nor the seal36are liable to become damaged.

The seal36is made of an elastically deformable elastomeric material. The annular seal36in this instance is formed of the free lower end of an axial sleeve tube40which is arranged externally around the nozzle32. The sleeve tube40is fixedly mounted in a ring39able to slide vertically around the nozzle32. The downward vertical sliding of the seal36is limited by this ring39coming vertically into abutment against the upper end edge of the neck20.

The expansion of the annular seal36is brought about by the axial sliding of a conical wedge38of axial axis with respect to the annular seal36. The wedge38has an annular shape of an outside diameter substantially equal to the inside diameter of the sleeve tube40. The wedge38is borne fixedly by an external cylindrical wall of the nozzle32.

The wedge38in this instance is produced as an integral part of the nozzle32.

The nozzle32is mounted such as to slide in the casing27in order to allow the wedge38to slide.

Further, the vertical sliding of the seal36between its two positions is brought about by the vertical sliding of the nozzle32.

Taking as a reference the lower position of injection of the device24, the nozzle32is thus mounted such as to slide vertically in the casing27between:an extreme raised position, as illustrated inFIGS. 1 and 2, in which the lower end of the nozzle32is arranged in the neck20, and in which the seal36is in its contracted state;an intermediate position of insertion of the seal36, as depicted inFIG. 3, in which the seal36is driven by the nozzle32toward its lowered position of insertion; andan extreme lowered plugging position, as depicted inFIG. 4, in which the seal36is made to switch into its expanded state by the wedge38.

In its extreme lowered plugging position, the lower end of the nozzle32is arranged near the neck20so as to be nearer to the neck20than to the bottom of the container18.

The internal face of the annular seal36has a slope inclined toward the axis “A” from the top downward in the direction of the arrow “F1” ofFIG. 4. The external face of the wedge38has a slope similar to that of the seal36. Thus, the seal36is made to switch between its two states by the sliding of the wedge38:from an upper position of rest, which corresponds to the intermediate position of the nozzle32, and in which it is arranged above the seal36,to a lower position of expansion, which corresponds to the extreme lowered position of the nozzle32, and in which the seal36is expanded by contact between said slopes.

According to an undepicted alternative form of the invention, it is the annular seal which is mounted to slide vertically with respect to the wedge which is fixed.

The wedge38is made to slide by a piston41arranged at the upper end of the nozzle32.

According to other alternative forms of the invention, it will be understood that the wedge may be moved by other means, such as electrical, mechanical or magnetic means.

The nozzle32is arranged concentrically inside the sleeve tube40.

The nozzle32extends upward inside the pipe30as far as the piston31some distance above the ring39. Further, the nozzle32is open axially at the top so as to allow the filling liquid to pass.

The piston41is mounted to slide vertically in a cylinder42formed in the casing27. The piston41thus divides the cylinder42in a fluidtight manner into an upper chamber42A and a lower chamber42B. Each fluidtight chamber42A,42B has just one associated supply orifice (not depicted).

The piston41, the nozzle32and the wedge38thus form an assembly that slides as one between an upper position of rest and a lower position of expansion.

To allow the joint sliding of the nozzle32and of the seal36, a compression spring (not depicted) is, for example, inserted vertically between the piston41and the ring39. Thus, when the ring39is in abutment against the neck20, the downward sliding of the piston41drives the nozzle32toward its extreme lowered position, compressing the spring.

As an alternative, the ring is in abutment near the neck, against an abutment element of the bell.

Each of the orifices is connected to a controlled source of pressurized fluid which in this instance is made up of the same source as the blow-molding gas. Each orifice is fitted with pressurized-fluid supply valves (not depicted). The valves can be operated in such a way as to vary the pressure in each of the chambers42A,42B.

The operation of the injection device24equipped with the controlled sealing mechanism34is now described.

When the injection device24is in its upper standby position, depicted inFIG. 1, a container18is inserted into the mold12. Then the injection device24is made to move into its lower position of injection, depicted inFIG. 2, in which the bell26covers the neck20in a fluidtight manner, and in which the nozzle32is inserted inside the neck20.

The nozzle32is then in its extreme upper position. The piston41therefore occupies its upper position of rest. For that, the lower chamber42B is kept at a pressure higher than that of the upper chamber42A. The seal36is in its raised retracted position, thus leaving the first radial gap “j1” open for the passage of blow-molding gas coming from the bell26at an optimal flow rate.

The piston41remains in this upper position of rest during the filling of the container18with the filling liquid. Thus, the blow-molding gas contained in the container18is able to escape to the bell26by passing through the first radial gap “j1” as the level of filling liquid gradually rises.

When the container18is filled with a determined percentage of the volume, for example 80%, the nozzle32is made to move by the piston41toward its intermediate position of insertion of the seal36into the neck20, as depicted inFIG. 3. The second radial gap “j2” then remains in order to allow the residual blow-molding gas to escape.

According to an undepicted alternative form of the invention, the nozzle is made to move toward its intermediate position far sooner, for example right at the start of the filling with the filling liquid.

When it is necessary to pressurize the container18full of filling liquid to a high pressure, for example 40 bar, the piston41is made to move into its extreme lower position, as depicted inFIG. 4. To do this, the valves are operated in such a way that the pressure in the upper chamber42A is higher than that of the lower chamber42B.

The wedge38then applies to the seal36a force of outward radial expansion. The seal36is therefore deformed into its expanded position in which the second radial gap “j2” is completely plugged.

The high pressure in the container18then applies an outward radial force directly to the sleeve tube40to supply the action of the wedge38.

The injection device24produced according to the teachings of the invention thus allows two different fluids to be injected into one and the same container18, the second fluid passing through a central nozzle32, while the first fluid passes through a first radial gap “j1” left between the central nozzle32and the neck20of the container18.

Furthermore, the controlled sealing mechanism34allows the first radial gap “j1” to be plugged easily and completely in order to cause the pressure of the second fluid to rise without the risk of leakage.