Method and apparatus for producing plastic preforms and plastic containers with thermal preform storage

Abstract

Method for operating an apparatus for producing plastic preforms and plastic containers, comprising at least one injection moulding machine and one blow moulding machine, wherein the plastic preforms are injection moulded within the injection moulding machine and are formed into plastic containers within the blow moulding machine and are transported from the injection moulding machine to the blow moulding machine, wherein a heating device is arranged downstream of the injection moulding machine and the injection moulding machine and the blow moulding machine are coupled to one another. According to the invention, the plastic preforms produced in the injection moulding machine are transferred directly after production to a thermal preform storage, which holds the plastic preforms at a predetermined temperature and wherein a speed and/or at least one parameter of at least one subsequent treatment device can be changed.

Claims

1. A method for operating an apparatus for producing plastic preforms and plastic containers, comprising at least one injection moulding machine and a blow moulding machine, wherein the plastic preforms are injection moulded within the injection moulding machine and are formed into plastic containers within the blow moulding machine and are transported from the injection moulding machine to the blow moulding machine, and wherein downstream of the injection moulding machine a heating device is arranged which heats the plastic preforms to a temperature necessary for the blow moulding, wherein the injection moulding machine and the blow moulding machine are coupled to one another, characterised in that the plastic preforms produced in the injection moulding machine are transferred directly after production to a thermal preform storage which keeps the plastic preforms at a predetermined constant temperature and wherein a speed and/or at least one parameter of at least one subsequent treatment device can be varied and this speed and/or this at least one parameter is adapted to an energy content of the plastic preform, wherein the preforms are not actively heated within the thermal preform storage by means, but are kept at the temperature at which they are fed into the thermal preform storage, so that an inlet temperature of the preforms into the thermal preform storage corresponds to an outlet temperature of the preforms from the thermal preform storage.

2. The method according to claim 1, characterised in that the plastic preforms are blocked at the outlet of the thermal preform storage and/or at the inlet of the heating device for heating the plastic preforms.

3. The method according to claim 1, characterised in that the temperature inside the thermal preform storage is kept substantially constant.

4. The method according to claim 1, characterised in that the plastic preforms can remain timely indefinitely within the thermal preform storage without the temperature of the plastic preforms increasing.

5. The method according to claim 1, characterised in that the temperature between successive plastic preforms when entering the heating device is +/−1° C.

6. An apparatus for producing plastic preforms and plastic containers, comprising at least one injection moulding machine for injection moulding the plastic preforms and a blow moulding machine for forming the plastic preforms into plastic containers, wherein the injection moulding machine and the blow moulding machine can be coupled to one another and with a transport device for transporting the plastic preforms from the injection moulding machine to the blow moulding machine, wherein the apparatus further comprises a heating device arranged downstream of the injection moulding machine, within which the plastic preforms can be heated to a temperature necessary for the blow moulding, characterised in that the plastic preforms produced in the injection moulding machine are transferred directly after production to a thermal preform storage which keeps the plastic preforms at a predetermined constant temperature and wherein a sensor device is provided between the thermal preform storage and a heating device for heating the plastic preforms, which measures a value of a preform which is characteristic of the energy content, wherein this value being transferred to a control device with which a speed and/or at least one parameter of at least one subsequent treatment device is regulated, wherein the preforms are not actively heated within the thermal preform storage by means, but are kept at the temperature at which they are fed into the thermal preform storage, so that an inlet temperature of the preforms into the thermal preform storage corresponds to an outlet temperature of the preforms from the thermal preform storage.

7. The apparatus according to claim 6, characterised in that a blocking device is provided at the outlet of the thermal preform storage and/or at the inlet of the heating device.

8. The apparatus according to claim 6, characterized in that the thermal preform storage is arranged upstream of the injection moulding machine and downstream of the blow moulding machine.

9. The apparatus according to claim 6, characterised in that the subsequent treatment unit is a heating device for heating the plastic preforms, a blow-moulding machine for forming the plastic preforms into plastic containers, a labelling device for labelling the plastic containers, a filling device for filling the plastic containers or the like.

Description

(1) Further advantages and embodiments can be seen in the attached drawings.

(2) In it shows:

(3) FIG. 1 a schematic representation of an embodiment according to the invention of an apparatus for producing plastic preforms and plastic containers with thermal preform storage; and

(4) FIG. 2 a graphical representation of the temperature curve of the plastic preforms.

(5) FIG. 1 shows a schematic representation of an apparatus 1 according to the invention for producing plastic preforms 10 and plastic containers 20. The reference sign 2 refers to an injection moulding machine in which the plastic preforms 10 are produced. After production, the plastic preforms are transferred to the thermal preform storage 3 and kept here at a constant temperature T1, which corresponds to the temperature at which the plastic preforms leave the injection moulding machine 2.

(6) The plastic preforms can preferably be prevented from being transported further at the outlet 25 of the thermal preform storage 3 by means of a blocking device 18 if, for example, a downstream machine has been stopped. Otherwise, the plastic preforms pass through the preform storage 3 in a predetermined time and then enter a sorting device 4, which sorts the preforms in a predetermined manner and, in particular, in an identical manner, before the plastic preforms are fed to the heating device 8 by means of a transport device 5 along the transport path X or the preform feed 6. A blocking device 18 can again be provided at the inlet 26 of the heating device 8.

(7) During transport along the transport path X, the plastic preforms lose heat and cool down to the temperature T2. In order to keep this cooling or this loss of energy content of the preforms as low as possible, the transport device 5 or the preform feed 6 is preferably designed to be as short as possible. Ideally so short that there is no temperature loss. The preforms are thus fed to the heating device 8 at a temperature T2, wherein T2<T1, and heated here to a temperature necessary for blow moulding by means of a plurality of heating elements 13 arranged along the transport direction T. However, due to the thermal storage 3, this heating requires considerably less time and energy than without the arrangement of a thermal storage, in particular in the event of a malfunction or stop of a downstream machine, such as a labelling machine or a filling machine.

(8) After heating in the heating device 8, the plastic preforms are fed to the blow moulding machine 9 via, for example, a (schematically shown) feed wheel 15, wherein the plastic preforms 10 are here formed into plastic containers 20 within blow moulds 12. The reference sign 30 schematically indicates a control device which can, for example, regulate or control a speed of the heating device 8 and the blow-moulding machine. The plastic containers 20 are discharged from the blow moulding machine 9 via a discharge wheel (shown schematically).

(9) FIG. 2 shows a graphical representation of the temperature curve of the plastic preforms 10. Section I indicates the temperature curve during injection moulding. It can be seen that the temperature of the preforms can rise to approx. 280° C. during injection moulding and that the preforms leave the injection moulding machine at approx. 50° C. and enter the thermal storage at this temperature in section II and are kept at this temperature.

(10) Sections III and IV identify the sorter and the preform transport, wherein the preforms ideally remain at the same temperature of approx. 50° C. here. Section V marks the heating and stretch blow moulding, wherein the plastic preforms are heated here to a temperature of approx. 100° C. and are formed into plastic containers or stretch blown at this temperature.

(11) The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are individually or in combination new compared to the prior art. It is further pointed out that the individual figures also describe features which may be advantageous in themselves. The skilled person immediately recognises that a certain feature described in a figure can also be advantageous without adopting further features from this figure. Furthermore, the skilled person recognises that advantages can also result from a combination of several features shown in individual figures or in different figures.

LIST OF REFERENCE SIGNS

(12) 1 apparatus 2 injection moulding machine 3 thermal preform storage 4 sorting device 5 transport device 6 preform feed 8 heating device 9 blow moulding machine 10 plastic preforms 12 blow mould 13 heating elements 15 feed wheel 16 discharge wheel 18 blocking device 20 plastic containers 25 outlet of the thermal preform storage 3 26 inlet of the heating device 8 30 control device T transport direction within the heating device 8 X Transport route I injection moulding II thermal storage III sorter IV preform transport V heating-stretch blowing