Method and apparatus for packaging a liquid food product

Abstract

The invention relates to a method of delivering a predetermined volume of beverage into a thermoplastic container formed from a heated preform positioned in a mold, characterized in that the product includes a step of injecting at least some beverage into a recess in the preform so as to promote expansion of the preform inside the mold, the mold defining the shape of the container, a volume of beverage introduced during the injection step being at least equal to said predetermined volume, and, in addition, the method includes a step of sucking out a fraction of said volume of the beverage introduced until the volume of beverage remaining in the container is approximately equal to said predetermined volume.

Claims

1. A method of delivering a predetermined volume of a beverage component into a thermoplastic container formed from a heated preform positioned in a mold defining the shape of the container, the method comprising injecting a first volume of at least one beverage component into a recess in the preform so as to promote expansion of the preform inside the mold into the shape of the container, the first volume intentionally being greater than the predetermined volume, and removing a fraction of the first volume from the container resulting in a second volume of the at least one beverage component remaining in the container, the second volume being equal to the predetermined volume.

2. The method of claim 1, wherein the injection step includes longitudinally stretching the preform by a stretch rod, the stretch rod being hollow, and the removing step comprises removing out some of the beverage component via the hollow stretch rod.

3. The method of claim 1, comprising recirculating at least part of the beverage component removed during the removing step.

4. The method of claim 1, wherein the removing step comprises suction using a vacuum pump.

5. The method of claim 1, wherein the injection step comprises injecting the at least one beverage component through a hollow stretch rod that is designed to stretch a thermoplastic preform and is connected to a beverage inlet.

6. The method of claim 5, wherein the stretch rod injects the at least one beverage component and removes the fraction of the first volume.

7. The method of claim 6, wherein the stretch rod has a profile adapted to minimize the turbulence in a liquid during the step of injecting the first volume of the at least one beverage component via the hollow stretch rod.

8. The method of claim 7, wherein the profile includes an internal profile.

9. The method of claim 7, wherein the profile includes an external profile.

10. The method of claim 1, wherein the injection is performed using a bell-shaped filling head.

11. The method of claim 1, wherein the stretch rod is designed in such a way that its internal volume is optimized so that the fraction of the first volume is reduced.

12. The method of claim 11, wherein the fraction of the first volume is reduced to the internal volume of the neck.

13. The method of claim 1, wherein the injection step comprises injecting the first volume of the at least one beverage component through the inside of the stretch rod and through an orifice around the stretch rod.

14. The method of claim 1, wherein the injection step comprises a step of injecting a first beverage component and a step of injecting a second beverage component.

15. The method of claim 14, wherein the injection of the first beverage component comprises injection through the inside of the stretch rod and the injection of the second beverage component comprises injection through an orifice around the stretch rod.

16. The method of claim 1, wherein the at least one beverage component is injected with a stretch rod and an actuator that comprises two upper chambers filled with compressed air, and wherein a piston wall slides between the two upper chambers in a direction parallel to the stretch rod.

17. The method of claim 16, wherein the actuator further comprises a bottom chamber connected to a lateral inlet for the at least one beverage component.

Description

(1) The invention will now be described in detail with reference to the appended figures, which relate to exemplary embodiments.

(2) FIG. 1 shows a general diagram of an installation suitable for operating with the invention.

(3) FIG. 2 shows an important aspect of the invention.

(4) FIG. 3 shows a bell-shaped nozzle end-piece used within the context of the invention.

(5) FIG. 4 shows the monitoring of the formation of a mineral water bottle according to one example of the use of the invention.

(6) The embodiment given here by way of example relates to a process for manufacturing PET mineral water bottles from a heated preform. The preform has the shape of a cylindrical tube closed at its lower end. The open head of the preform corresponds to the throat or neck of the bottle, onto which a closure cap is screwed.

(7) Referring to FIG. 1, a stretch rod 10 is inserted into a compressed-air actuator 15. The stretch rod 10 is generally controlled by an air actuator associated with a cam, which gives it a longitudinal movement (represented by an arrow). It is also possible to use a stretch motor.

(8) The compressed-air actuator 15 comprises a cylinder 17 controlling an injection head 18, through which the stretch rod 10 passes. The injection head 18 is connected to the neck 20 of a PET preform placed in a mould (not shown), which preform, after being expanded, takes on the shape of a mineral water bottle, this shape being determined by the wall of the mould.

(9) The actuator comprises three chambers, the upper two chambers 15a and 15b being filled with compressed air. Between these upper two chambers, a piston wall 19 slides in a direction parallel to the stretch rod (the displacement being represented by an arrow). The stretch rod 10 passes through the centre of this wall 19.

(10) The compressed-air actuator also includes a lateral inlet 30 for the beverage, here mineral water, connected to the third chamber 15c of the actuator, this being the bottom chamber. The beverage is fed in via a line 32.

(11) An external mineral water inlet feeds the liquid via the remote end of this line 32 into a first valve 34, which is connected to the opening of a single-chamber filling cylinder 40 comprising a piston 42 controlled by a filling motor (movement of which is represented by an arrow). This motor imparts a longitudinal movement on the piston in the single chamber of the filling cylinder 40.

(12) On the line 32 there is a second valve 36, which is in series behind the first valve 34 and the opening of the filling cylinder 40. The line 32 then runs into the bottom chamber 15c of the compressed-air actuator 15.

(13) The bottom chamber 15c of the compressed-air actuator is penetrated by the cylinder 17 for controlling the filling head 18, the internal volume of which emerges through the lower outlet of the compressed-air actuator 15 into the filling head 18. The control cylinder has a lateral opening 25 allowing the beverage to circulate between the bottom chamber of the actuator and the inside of the control cylinder.

(14) The stretch rod 10 itself passes through the control cylinder 17 as far as the filling head 18 and the neck 20 of the bottle preform.

(15) Referring to FIG. 2, showing an alternative embodiment, a pressurizing actuator 100 increases the pressure of the beverage in the beverage feed line 110. A volumetric sensor 120 allows the volume injected through the line 110 to be monitored. The beverage is introduced into the nozzle 130.

(16) The stretch rod 140 is introduced along the axis of the nozzle 130.

(17) A suction pump 150 is attached to a line 170 connected via a volumetric sensor to the nozzle 130.

(18) The nozzle 130 is positioned facing the mould (not shown) in which the PET preform, to be expanded and filled with beverage, here mineral water, is positioned. After the expansion phase, a PET water bottle 180 is formed.

(19) Referring to FIG. 3, a bell-shaped nozzle end-piece 500 according to a preferred embodiment is shown. The internal and external pressures on either side of the circumference of the neck of the preform (i.e. on the external surfaces 510 of the neck and on the internal surfaces 520 of the neck) are identical, owing to the presence of a passage 505 connecting the volumes on either side of the circumference, inside the nozzle. During filling, sealing is provided by the flange 530 on the preform. Thanks to this device, there is no risk of the neck of the preform deforming while a pressurized fluid is being injected by the nozzle.

(20) According to another embodiment, a nozzle end-piece holds the external surfaces 510 of the neck of the preform in such a way that when a pressurized fluid is injected via the top of the nozzle into the recess of the preform, the pressure exerted on the internal walls 520 of the neck of the preform by the fluid is compensated for by the holding by the walls of the bell-shaped nozzle end-piece. The neck of the preform therefore does not deform, despite the high pressure.

(21) FIG. 4 shows the variation over time of the position 101 of the stretch rod and the position 102 of the filling actuator controlling the inflow of the mineral water into the expanded preform.

(22) The horizontal axis represents the time, the left-hand vertical axis represents the position of the stretch rod and the right-hand vertical axis represents the volume of water introduced into the expanded preform, this being proportional to the position of the filling actuator.

(23) During a first part of the process, from 0 to 250 ms, the stretch rod advances at an essentially constant rate, according to a preferred embodiment.

(24) However, according to another embodiment, during a first phase 110 of the process, in particular from 0 to 150 ms, the stretch rod advances at an increasing speed due to a positive acceleration. During a second phase 115 of the process, from 150 ms to 250 ms, the stretch rod advances with a negative acceleration, the speed decreasing until it becomes zero at 250 ms. However, it will be understood that the changes in speed must be sufficiently gentle to ensure regular and reliable stretching of the thermoplastic.

(25) 250 ms after the start of the process (reference 103), the stretch rod has reached its final position P.sub.f, from which it no longer moves.

(26) At the same instant, the filling actuator has introduced a volume V.sub.1 of mineral water into the expanded preform. The volume introduced from the start of the process (therefore between 0 ms and 250 ms) has progressively increased, with a progressive increase in the flow rate (filling actuator displacement acceleration).

(27) During the moments that follow, which constitute a third phase 120 of the process, up to 320 ms, the total volume of water introduced is constant, the flow rate being invariant. Next, the volume suddenly decreases by a small fraction (around 4%) over a period of 40 ms.

(28) From this instant on, the total volume introduced stabilizes around the value V.sub.2, which is finally reached after a few oscillations, the flow rate of liquid being introduced being zero.

(29) A few instants later, starting from 450 ms after the start of the process (reference 104), the filling actuator has reached a final position, from which it no longer moves. At this moment, it has introduced a volume V.sub.2 of mineral water into the expanded preform. The volume V.sub.2 is greater than V.sub.1, but less than twice the volume V.sub.1.

(30) During the method of using the device described, the temperature of the preform is brought beforehand to a value between 50 C. and 130 C., or even between 75 C. and 100 C. In the preferred embodiment, this value is 95 C., the plastic used being PET.

(31) The rod has a speed of between 0.5 and 3.0 m/s.sup.1, or even between 1.0 and 5 m/s.sup.1. In the preferred embodiment, this value is 1.6 m/s.sup.1.

(32) The temperature of the beverage is brought beforehand to a value between 1 C. and 120 C., preferably between 10 C. and 90 C. In the preferred embodiment, this value is 30 C.

(33) The longitudinal stretch ratio of the thermoplastic is between 2 and 5 or even between 2.5 and 4. In the preferred embodiment, this value is 3.5.

(34) The radial stretch ratio of the thermoplastic is between 2 and 7, or even between 3 and 4.5. In the preferred embodiment, this value is 4.

(35) The thermoplastic is chosen from the group consisting of polyethylene terephthalates, polypropylenes, polyethylenes, polycarbonates, polystyrenes, polylactic acids, polyvinyl chlorides and combinations thereof. In the preferred embodiment, it is PET.

(36) The temperature of the mould is at least 50 C. below the melting point of the thermoplastic, which in the case of PET is 230 C. Preferably, this temperature is maintained below 100 C. In the preferred embodiment, the temperature of the mould is equal to the ambient temperature.

(37) Of course, the invention is not limited to the embodiments described and illustrated by the appended drawings; rather it extends to all variants that can be envisaged by a person skilled in the art within the scope of the claims.