EP2547590B1 - Control system and apparatus for controlling power consumption of a shrink tunnel. - Google Patents

Description

The invention relates to a shrink tunnel for applying shrink films on packaging units or containers according to the preamble of claim 1 or 2, to a method for operating or controlling a shrink tunnel according to the preamble of claim 11 or 12 and to a production plant with a shrink tunnel according to the preamble.

In production plants, especially in those of the beverage industry, it is known to supply the packaging, such as bottles, cans or other packaging, which were filled in a previous investment components or machines with a product, sealed and labeled, a downstream packaging machine, in which Packing means, for example, stacked together on packaging elements to packaging groups with a predetermined number of packaging and the packaging material groups thus generated are each covered with a shrink film. In a shrinking tunnel following the packaging machines, a fixed or fixed packaging unit is formed from each packaging material group by shrinking the shrinking film under the action of heat, in particular also by blowing with hot air.

In order to ensure shrinkage with the required quality, it is common practice in known systems to operate the shrink tunnel, which generally has a plurality of heating or tunnel zones, each having its own heating means, in successive heating or tunneling zones of the packaging units or packages all tunnel zones by appropriate control or regulation of the heating power of the heating means constantly required for the shrinkage of the shrink films target operating temperature, for example a temperature in the range between 195 ° C and 210 ° C, preferably at a temperature of about 200 ° C, even during Operational disturbances in which no packaging or packaging groups for shrinking the shrink film are moved through the shrink tunnel and, for example, by disturbances in the Shrink tunnels preceding or subsequent investment components or machines are conditional. The heating means are usually electric or gas-operated heating elements, in particular those of hot air blowers.

Although in such malfunctions due to the absence of moving through the shrink tunnel packaging or packaging groups required for maintaining the tunnel temperature or setpoint operating temperature heating power, for example, to about 40% to 45% of normal heating system in normal operation of the system requires this operation known shrink tunnel a significant energy consumption with significant energy or heating costs and, associated with unnecessarily high emissions and CO2 emissions.

A shrink tunnel is known ( US 2004/0083687 A1 ) for applying shrink films to articles or packaging units. A control unit provided on the shrink tunnel initiates a standby or economy mode with reduced power during a longer shutdown. The duration of the interruption can be set manually at the control unit. It is further provided that a shrink tunnel internal conveyor belt on which the objects or packaging units are moved through the Schrurnpftunnel is turned off when initiating the stand-by mode and only switched on when resetting the shrink tunnel in the normal operating state, when the shrink tunnel has reached the target operating temperature.

The invention has for its object to provide a shrink tunnel, which avoids these disadvantages. To solve this problem, a shrink tunnel according to claim 1 or 2 is formed. A method for operating or controlling a shrink tunnel is the subject matter of claim 11 or 12. A production plant for manufacturing packaging containers or containers with these enclosing and / or fixing shrink films is the subject of patent claim 18.

Advantageous embodiments are disclosed in the subclaims

The invention will be described below with reference to the figure, which in a simplified functional representation of a plant section 1 of a production plant for product-filled packaging 2, for example, with a liquid product, e.g. filled with a beverage packaging 2 shows, explained in more detail. The plant section of the production plant shown in the figure and generally designated 1 is used specifically for assembling the packaging material 2 filled with the product into packaging material groups 3 and for packaging each packaging material group 3 and the like. using a shrink film, so that the packaging material groups 3 each form after shrinking the shrink film packaging units or container 4, each with a predetermined number of packaging 2.

• Eine Puffer- oder Speichereinheit 5, die beispielsweise von einem Puffer- oder Speichertisch gebildet ist und die zur Zwischenspeicherung der dieser Einrichtung über einen äußeren Transporteur 6 in Transportrichtung A zugeführten Packmittel 2 dient.
• Eine Verpackungsmaschine 7 an, in der aus den Packmitteln 2 die Packmittelgruppen 3 gebildet werden, und zwar bei der dargestellten Ausführungsform jeweils auf oder in einem Verpackungselement 8, beispielsweise in Form eines kartonartigen Verpackungselementes oder eines Tableaus oder Trays in der Weise, dass jede Packmittelgruppe 3 die Packmittel 2 in einer vorgegebenen Anzahl und Zuordnung zueinander aufweist, beispielsweise bei der dargestellten Ausführungsform in zwei Reihen mit jeweils drei Packmitteln 2. In der Verpackungsmaschine 7 wird jede Packmittelgruppe 3 einschließlich seines Verpackungselementes 8 mit der Schrumpffolie umhüllt, und zwar bevorzugt derart, dass die einander überlappenden Enden dieser Umhüllung sich an der Unterseite der Packmittelgruppe 3 bzw. des Verpackungselementes 8 befinden.
• Die Verpackungselemente 8 oder diese bildenden Zuschnitte werden in der Verpackungsmaschine 7 über einen Transporteur 9 zugeführt (Pfeil B).
• Ein Schrumpftunnel 10, in dem das Aufschrumpfen der Schrumpffolie auf die jeweiligen Packmittelgruppen 3 zur Bildung der Verpackungseinheiten oder Gebinde 4 erfolgt, und zwar durch Hitzeeinwirkung, insbesondere auch durch Einwirkung von Heißluft auf die sich durch den Schrumpftunnel 10 in Transportrichtung A bewegten, mit der Schrumpffolie umhüllten Produktgruppen 3.

The packaging means 2 are, for example, bottles, cans or similar containers which are filled, sealed and labeled with the product. The plant section 1 has for this purpose in a transport direction A, in which the packaging means 2 or packaging material groups 3 and finally also the packaging units or containers 4 are moved, following one another, inter alia, the following system components with the following functions:

• A buffer or storage unit 5, which is formed for example by a buffer or storage table and which serves for the intermediate storage of this device via an outer conveyor 6 in the transport direction A supplied packaging 2.
• A packaging machine 7, in which the packaging means 3 are formed from the packaging means 2, in the illustrated embodiment in each case on or in a packaging element 8, for example in the form of a cardboard-like packaging element or a tray or tray in such a way that each packaging means group. 3 In the packaging machine 7, each packaging material group 3 including its packaging element 8 is wrapped with the shrink film, preferably such that the Overlapping ends of this envelope are located on the underside of the packaging material group 3 and the packaging element 8.
• The packaging elements 8 or these forming blanks are fed in the packaging machine 7 via a feed dog 9 (arrow B).
• A shrink tunnel 10, in which the shrinking of the shrink film on the respective packaging groups 3 to form the packaging units or container 4 takes place, by heat, in particular by the action of hot air on which moved through the shrink tunnel 10 in the transport direction A, with the shrink film wrapped product groups 3.

After leaving the shrink tunnel 10, the packaging units or containers 4 are fed via an external conveyor 11 to a further use or treatment, for example a device designed as a palletizer.

Within the plant section 1, the buffer or storage unit 5, the packaging machine 7 and the shrink tunnel 10 are interconnected by a transport system 12 formed by at least one conveyor or conveyor belt, but the shrink tunnel 10 is an independent and independently controllable transport system for the packaging material groups 3 and the packaging units or container 4 formed from these in the form of at least one endless circulating drivable conveyor belt 13 (eg Drahtgliedergurtkette or also hinge band) has.

As well as the packaging machine 7, the shrink tunnel 10, for example, the usual for this system components construction. Thus, in the illustrated embodiment, the shrink tunnel is designed, for example, with a plurality of heating or tunnel zones 14 which follow each other in the direction of transport A, for example with a total of three tunnel zones 14, as a result of which u.a. It is ensured that in normal trouble-free operation of the system or the shrink tunnel 10 even with a dense sequence of moving in the transport direction A through the shrink tunnel 10 Packmittelgruppen 3 shrinking of the shrink film on each packaging material group 3 takes place with the required quality. Each tunnel zones 14 is provided in the illustrated embodiment with its own, in the figure only very schematically 15 heating means which effect shrinkage of the shrink film on the packaging groups 3 by heat and at least one hot air generator consisting of at least one fan and at least one Fan associated with heater and optionally include at least one additional heater for a basic heating power. To avoid energy losses 10 slat curtains 16 are provided at the inlet and at the outlet of the shrink tunnel.

The shrink tunnel 10 also includes a cooling device, not shown (eg cooling air blower) with which the at least one conveyor belt 13 is cooled on a conveyor belt length outside of the shrink tunnel 10 and in the circumferential direction in front of the inlet of the shrink tunnel 10, so that each of the Shrink tunnel 10 supplied and wrapped with the shrink wrap packaging material group 3 is first transferred to the cooled conveyor belt 13. Furthermore, the shrink tunnel 10 in the direction of transport A to the tunnel zones 14 following a in the figure indicated by broken lines cooling zone 17, which among other things serves to cool the packaging units or container 4 and this example is equipped with a cooling air blower.

• Schrumpftunnel 10 bzw. dessen Tunnelzonen 14 befinden sich auf Sollbetriebstemperatur, die für das Aufschrumpfen der Schrumpffolie mit der angestrebten Qualität ausreicht. Diese Sollbetriebstemperatur, die die Tunneltemperatur im Inneren des Schrumpftunnels 10 bzw. im Inneren der Tunnelzonen 14 und dabei insbesondere auch wenigstens die Temperatur der in die Tunnelzonen 14 ausgebrachten Heißluft ist, beträgt beispielsweise 200°C.
• Das wenigstens eine Transportband 13 wird mit Produktionsgeschwindigkeit angetrieben, d.h. mit einer Geschwindigkeit, die der Leistung der Anlage und damit der Leistung Verpackungsmaschine 7 und der Transportgeschwindigkeit des Transportsystems 12 entspricht und in der Regel deutlich größer ist als 8 m/min.
• Die Heizmittel 15 werden zur Aufrechterhaltung der Sollbetriebstemperatur zwischen einer Grundheizleistung, die beispielsweise 10-15 KW für jede Tunnelzone 14 beträgt, und einer maximalen Heizleistung oder Gesamtheizleistung gesteuert oder geregelt, die beispielsweise 45-50 KW für jede Tunnelzone 14 beträgt.
• Die Kühleinrichtung 17 bzw. das dortige, Kühlluft erzeugende Gebläse ist eingeschaltet.

In the trouble-free operating state of the system, the shrink tunnel 10 is operated in its normal operating state or operating mode, which is characterized, inter alia, by the following operating parameters:

• Shrink tunnel 10 or its tunnel zones 14 are at target operating temperature, which is sufficient for shrinking the shrink film with the desired quality. This target operating temperature, which is the tunnel temperature in the interior of the shrink tunnel 10 or in the interior of the tunnel zones 14 and in particular also at least the temperature of the hot air introduced into the tunnel zones 14, is for example 200 ° C.
• The at least one conveyor belt 13 is driven at production speed, ie at a speed that corresponds to the performance of the system and thus the performance of the packaging machine 7 and the transport speed of the transport system 12 and is generally significantly greater than 8 m / min.
• The heating means 15 are controlled to maintain the desired operating temperature between a base heating power, for example, 10-15 KW for each tunnel zone 14, and a maximum heating power or total heating power, for example, 45-50 KW for each tunnel zone 14.
• The cooling device 17 or the local, cooling air generating blower is turned on.

A special feature of the system or the shrink tunnel 10 is that when occurring in the system disturbances of the shrink tunnel 10 and its tunnel zones 14 occupy a standby mode or standby mode with respect to the normal, trouble-free operating condition significantly reduced power and after removing the fault again automatically return to normal operating condition. Such disturbances causing the standby mode are, for example, a number of packaging means 2 in the buffer and storage unit 5 which falls below a predetermined minimum quantity of packaging material and / or a packaging jam within the installation, for example in an installation section preceding and / or following the shrinking tunnel 10 with respect to the transport direction A. The control of the shrink tunnel 10 between the two operating states is carried out automatically, ie in the illustrated embodiment by an electronic control device 18, for example, the shrunken tunnel 10 associated control device with its own intelligence and also controls the heating means 15 to comply with the respectively required tunnel temperature or controls , The control device 18, which is connected, for example via an unillustrated bus system with other control devices or with a central or higher-level system control, controls the switching between the operating states of the shrink tunnel 10 (normal operating mode / standby mode) in response to error messages such as the higher-level system control and / or depending on other signals. Preferably, in the control device 18 for detecting interference present signals are at least partially processed, which are used to control other equipment components, such as the control of the packaging machine 7. Such signals are eg "shortage in the buffer or storage unit 5" and / or "lack of packaging in the packaging machine 7 ", and / or" minimum product "as examples of fault conditions in the transport direction A in front of the shrink tunnel 10, and / or" back pressure external "and / or" lack of pallets "for fault conditions in the transport direction A after the shrink tunnel 10, etc.

• Absenken der Tunneltemperatur um einen vorgegebenen Betrag ΔT, beispielsweise um 50°C bis 80°C, vorzugsweise um etwa 50°C unter die Sollbetriebstemperatur, wobei diese Temperaturabsenkung bzw. der Betrag ΔT vor Ort am Schrumpftunnel 10 bzw. an einer Eingabe der Steuereinrichtung 18 zur Anpassung an die konkreten Produktionsbedingungen einstellbar ist, und zwar beispielsweise auch für jede Tunnelzone 14 individuell.
• Abschalten der Grundlast, d.h. der die Grundheizleistung erbringenden Heizelemente, was zumindest in erster Linie für ein Beheizen des Schrumpftunnels 10 mit elektrischer Energie gilt, während bei einem Betrieb des Schrumpftunnels 10 mit Gas schon aus Sicherheitsgründen das Beheizen der Tunnelzonen 10 ausschließlich mit Heißluft erfolgt. Bei einem Absenken der Tunneltemperatur um den Betrag ΔT erfolgt bei einem gasbetriebenen Schrumpftunnel 10 zwangsläufig eine entsprechende Reduzierung der Grundheizleistung, d.h. die Heizelemente bzw. Gasbrenner regeln sich selbsttätig auf die jeweils benötigte Leistung und schalten ggs. auch kurzzeitig ab.
• Reduzierung der Transportgeschwindigkeit des schrumpftunnelseitigen Transportsystems bzw. des wenigstens einen Transportbandes 13 auf eine Transportgeschwindigkeit, die nur noch 20% bis 40% der Transportgeschwindigkeit des normalen Betriebszustandes des Schrumpftunnels 10 entspricht.
• Abschaltung der Kühlung der Kühlzone 17 für das Kühlen der Verpackungseinheiten oder Gebinde 4 und des wenigstens einen Transportbandes 13.
• Abschalten eines Gebläses je Tunnelzone 14, sofern jeder Tunnelzone 14 wenigstens zwei elektrisch betriebene Gebläse zugeordnet sind, wie dies in der Regel der Fall ist.

Standby mode initiates the following actions, which can be taken individually or in any combination:

• Lowering the tunnel temperature by a predetermined amount .DELTA.T, for example by 50 ° C to 80 ° C, preferably by about 50 ° C below the target operating temperature, said temperature decrease or the amount .DELTA.T locally on the shrink tunnel 10 or at an input of the control device 18th is adjustable to adapt to the specific production conditions, and for example, for each tunnel zone 14 individually.
• Switching off the base load, that is, the heating elements that provide the basic heat output, which is at least primarily for heating the shrinking tunnel 10 with electrical energy, while during operation of the shrink tunnel 10 with gas for safety reasons, the heating of the tunnel zones 10 takes place exclusively with hot air. With a lowering of the tunnel temperature by the amount .DELTA.T takes place in a gas-powered shrink tunnel 10 inevitably a corresponding reduction of the Grundheizleistung, ie the heating elements or gas burners regulate themselves automatically to the power required in each case and switch ggs. also for a short time.
• Reduction of the transport speed of the shrinking tunnel side transport system or of the at least one conveyor belt 13 to a transport speed which corresponds to only 20% to 40% of the transport speed of the normal operating state of the shrink tunnel 10.
• Switching off the cooling of the cooling zone 17 for the cooling of the packaging units or containers 4 and the at least one conveyor belt thirteenth
• Switching off a fan per tunnel zone 14, if each tunnel zone 14 at least two electrically operated blowers are assigned, as is usually the case.

The standby mode, which is preferably also on-site, i. can be triggered at the shrink tunnel 10 or at the control device 18 is initiated delayed with a time delay .DELTA.t1. The duration of this time delay .DELTA.t1 is preferably chosen to be sufficiently long, so that those packaging material groups 3, which at the time of receipt of at least one causing the transition to the stand mode error message already in the shrink tunnel 10 and possibly also in a shrink tunnel with respect to the transport direction A preceding Section of the system, for example, in the packaging machine 7 and / or on the transport system 12 between the packaging machine 7 and the shrink tunnel 10 are reliably treated in the shrink tunnel 10 with high reliability, ie the shrink film is shrunk even on these groups of packaging 2 still properly. The time delay Δt1 at which the standby mode is initiated is, for example, 1 to 2 minutes.

The return of the shrink tunnel 10 from the standby mode in the normal operating mode or mode is also delayed, ie with a time delay .DELTA.t2, for example, from 2 to after the elimination of the error message (s) and due to the time required for re-heating to the desired operating temperature 3 minutes. Only after this time delay, the packaging machine 7 is turned on again, which of course was switched off during standby mode of the shrink tunnel 10 or in a stand-by mode. A re-switching the packaging machine 7 and the packaging material groups 3 to the shrink tunnel 10 promotional transport system 12 takes place only when the tunnel temperature has reached a target operating temperature strongly approximated temperature value. The switching on of the packaging machine 7 and preferably also of the transport system 12 is then caused by a corresponding signal supplied by the control device 18.

The standby mode results in disturbances in the system a very significant energy savings, in particular, a very significant savings in heating energy and thus a significant reduction in exhaust emissions and in particular the CO2 emission in gas-powered shrink tunnel 10.

As stated, in conventional systems, even in case of malfunction, i. when no package groups 3 are moved through the shrink tunnel for shrink-wrapping their shrink film, the operating temperature of the shrink tunnel is maintained at the normal target operating temperature, for example at the operating temperature of 200 ° C. This requires a heating power that, while reduced due to the lack of moving through the shrink tunnel product groups 3 compared to the heating power in normal, trouble-free operation, but still means a heating power that corresponds to about 40% to 50% of the total power of the shrink tunnel in normal trouble-free operation and for example in conventional shrink tunnels in the range between 40 KW and 45 KW.

In a particular embodiment of the shrink tunnel 10, the nominal operating temperature of which is 200 ° C in normal trouble-free operation, at a temperature drop ΔT of 50 ° C, i. to a reduced tunnel temperature of 150 ° C in the standby mode, a reduction of the heating power to 5.4 KW and a temperature decrease ΔT of 80 ° C, i. to a reduced tunnel temperature of 120 ° C, a reduction of the heating power to 4.6 kW found, the heating times to the target operating temperature 2.5 minutes at the temperature reduction .DELTA.T of 50 ° C and 4 minutes at the temperature drop .DELTA.T of 80 ° C.

Even taking into account the length of time required after the initiation of the standby mode for the temperature drop from the target operating temperature to the reduced tunnel temperature of the standby mode, for example 8 to 10 minutes, a considerable energy saving potential results switching to standby mode. For example, the energy savings for a 10-minute disruption or interruption of operation is between 1.44 KWh and 5.76 KWh, and for a 30-minute disturbance or interruption is approximately 18 KWh, including that for the reheat after completion of the operation destruction necessary heating energy.

A significant energy saving results further by switching off the cooling or cooling fan for the at least one conveyor belt 13 and the cooling zone 17 as well as by switching off at least one fan for the hot air in each tunnel zone 14, these blowers, for example, have a power requirement of about 3 KW ,

• Rücksetzen der Tunneltemperatur der einzelnen Tunnelzonen 14 auf die erforderliche und an der Steuereinrichtung 18 eingestellte und/oder dort abgelegte Sollbetriebstemperatur und Einschalten sämtlicher Heizmittel 15 bzw. sämtliche Heizeinrichtungen und Heizluftgebläse;
• Rücksetzen der Transportgeschwindigkeit des wenigstens einen Transportbandes 13 auf Produktgeschwindigkeit und Einschalten der Transportbandkühlung für das wenigstens eine Transportband 13 dann, wenn die Tunneltemperatur in sämtlichen Tunnelzonen 14 beim Wieder-Aufheizen einen Temperaturschwellwert erreicht hat, der etwa 5% bis 7%, beispielsweise etwa 5% oder 10°C unter der Sollbetriebstemperatur liegt;
• Freigabe bzw. Einschalten der Verpackungsmaschine 7 sowie Einschalten der Kühlung für die Verpackungseinheiten oder Gebinde 4, d.h. Freigabe der Produktion dann, wenn die Betriebstemperatur in sämtlichen Tunnelzonen 14 beim Aufheizen einen Temperaturschwellwert erreicht hat, der geringfügig, d.h. beispielsweise 2 bis 3%, z.B. 5°C unterhalb der Sollbetriebstemperatur liegt.

The reset of the system and the shrink tunnel in the normal operating state, ie the production release and the startup of the shrink tunnel 10 in the normal operating state after deleting the error messages, for example, in the following steps:

• Resetting the tunnel temperature of the individual tunnel zones 14 to the required set operating temperature set and / or stored at the control device 18 and switching on all the heating means 15 or all the heating devices and heating air blower;
• Resetting the transport speed of the at least one conveyor belt 13 to product speed and switching on the conveyor belt cooling for the at least one conveyor belt 13, when the tunnel temperature has reached a temperature threshold in all tunnel zones 14 during reheating a temperature threshold of about 5% to 7%, for example about 5% or 10 ° C below the target operating temperature;
• Enabling or switching on the packaging machine 7 and switching on the cooling for the packaging units or containers 4, ie release of production, when the operating temperature has reached a temperature threshold in all tunnel zones 14 during heating, the slightly ie, for example, 2 to 3%, for example, 5 ° C below the desired operating temperature.

The operating parameters and the standby mode characterizing operating parameters, in particular the target operating temperature, the temperature decrease .DELTA.T and / or the reduced tunnel temperature, the time delays At1 and .DELTA.t2, the reduction of the transport speed of the shrink tunnel transport system and the at least one conveyor belt 13, etc. are as a control - or control parameters on the control device 18 adjustable and / or stored there in a data memory.

In a preferred embodiment of the invention, at least one further standby mode or standby mode is provided for the shrink tunnel 10, which is initiated according to other criteria or parameters and / or has other measures than the standby mode described above, which is initiated in case of malfunction in the system. This further standby mode can be provided, for example, for planned production interruptions, in particular of known frequency, preferably with a longer duration and / or with planned start and end times, for example for planned or predetermined production breaks. Since the end of such scheduled production stoppages, for example the end of a daily recurring break, and hence the time at which production resumes, may be brought to a deeper standby mode during such a scheduled or fixed stoppage of production, i. The tunnel temperature in the tunnel zones 14 can be further reduced in comparison to the disruption-related standby mode, since the re-start, in particular the re-heating of the tunnel zones can be planned and timed.

The invention has been described above by means of an embodiment. It is understood that numerous changes and modifications are possible without that thereby the inventive concept underlying the invention is abandoned.

LIST OF REFERENCE NUMBERS

1

contact section

2

packaging

3

Packaging Group

4

Packaging unit or container

5

Buffer or storage unit

6

external transporter

7

packaging machine

8th

packaging element

9

Transport system for feeding the packaging elements 8

10

shrink tunnel

11

external transporter

12

transport system

13

conveyor belt

14

tunnel zone

15

heating

16

vertical blinds

17

cooling zone

18

electronic control unit

A, B

transport direction

.DELTA.T

Temperature reduction in standby mode

.DELTA.t1

Time delay when initiating standby mode

.DELTA.t2

Time delay in reheating the shrink tunnel 10

Claims (15)

1. Shrink tunnel for use in a production system for producing packaging units or containers (4) from packaging elements (2) filled with a product and with shrink film shrunk on, comprising at least one tunnel zone (14) having heating means (15) for shrinking the shrink film onto the packaging units (4) moved through the tunnel zone under the influence of heat at a tunnel temperature, which is a target operating temperature in the normal undisturbed operating state or operating mode of the shrink tunnel (10), wherein the shrink tunnel (10) comprises, as a further operating state, at least one stand-by mode with a reduced heating capacity in relation to the normal operating mode and with a conveying speed reduced in relation to the normal operating mode of a conveyor (13) on the shrink tunnel side, and with a control device (18) for controlling the operating modes, wherein the control device (18), when the shrink tunnel (10) is reset into the normal operating mode, sets the tunnel temperature back to the target operating temperature,
   characterised in that
   after the resetting of the shrink tunnel (10) into the normal operating mode, and already upon reaching a first temperature threshold value of the tunnel temperature which is still below the target operating temperature, the control device (18) increases the conveying speed of the shrink tunnel-side conveyor (13) again, and/or upon reaching a second threshold value which is closer to the target operating temperature, issues the signal which allows for clearance for production.
2. Shrink tunnel according to claim 1, characterised in that the control device (18) is configured for initiating the stand-by mode in the event of the presence of a signal, issued by a superordinated control device of the production system, which indicates an operational disturbance in the production system.
3. Shrink tunnel according to any one of the preceding claims, characterised in that the control device (18) for the controlling or regulating of the tunnel temperature in the shrink tunnel and/or in at least one tunnel zone (14), by way of the output of the heating means (15) which produce the tunnel temperature, is configured in such a way that, during the normal operating mode, the tunnel temperature corresponds to a target operating temperature in the range between 190 and 210°C, preferably a target operating temperature of 200°C, and in the stand-by mode the tunnel temperature in the at least one tunnel zone (14) is lowered to a reduced tunnel temperature by a temperature amount (ΔT) of 50°C to 80 °C in relation to the target operating temperature.
4. Shrink tunnel according to any one of the preceding claims, characterised by a plurality of tunnel zones (14) following one another in the conveying direction (A), wherein heating means (15) are allocated to each tunnel zone (14), which can be individually controlled or regulated for switching over the operating modes, and specifically as a function of control or regulating parameters set or deposited in the control unit (18).
5. Shrink tunnel according to any one of the preceding claims, characterised in that the heating means (15) of the at least one tunnel zone can be controlled or regulated between a heating output, corresponding to the base load, of 10 KW to 14 KW and a maximum heating output of 46 KW - 50 KW.
6. Shrink tunnel according to any one of the preceding claims, characterised in that the control device (18), is configured with a time delay (Δt1) for the initiation of the stand-by mode, in the event of the presence of a signal indicating an operational disturbance, such as to trigger the stand-by mode, for example with a time delay in the range of 1 to 2 minutes.
7. Shrink tunnel according to any one of the preceding claims, characterised in that the control device (18) is configured for reducing the conveying speed of the shrink tunnel-side conveyor (13) to 20% to 40% of the conveying speed of the normal operating mode and/or for switching off a cooling arrangement of the shrink tunnel-side conveying element (13) and/or a cooling arrangement which serves to cool the packing units (4) after the shrinking on of the shrink film, and/or for switching off the blower fans of the heating means (15) in each case after the initiation of the stand-by mode.
8. Shrink tunnel according to any one of the preceding claims, characterised in that the control device (18) is configured in such a way that, on reaching the first temperature threshold value, which lies 5% to 7% below the target operating temperature, it increases the conveying speed of the shrink tunnel-side conveyor (13) again, and/or switches on a cooling arrangement of this conveying system, and/or that the control device (18) is configured in such a way that, on reaching the second threshold value, which lies 2% to 5% below the target operating temperature, it issues the signal which allows for clearance for production, and/or switches on a cooling arrangement for the packaging units or containers.
9. Method for the operation or controlling of a shrink tunnel for use in a production system for producing packaging units or containers (4) from packaging elements (2) filled with a product and with shrink film shrunk on, wherein the shrink tunnel comprises at least one tunnel zone (14) with heating means (15) for shrinking the shrink film under the effect of heat onto the packaging units moved through the shrink tunnel (10) at a tunnel temperature which is a target operating temperature in the normal undisturbed operating state or operating mode of the shrink tunnel (10), and, in the event of disturbances for the shrink tunnel (10), a stand-by mode is initiated, time-controlled and/or signal-controlled, with a reduced capacity in relation to the normal operating mode, in particular with a reduced heating capacity and with a reduced conveying speed of a shrink tunnel-side conveyor (13),
   characterised in that
   after the resetting of the shrink tunnel (10) into the normal operating mode, and already upon reaching a first temperature threshold value of the tunnel temperature which is still below the target operating temperature, the conveying speed of the shrink tunnel-side conveyor (13) is increased again and/or again, and/or upon reaching a second threshold value which is closer to the target operating temperature, issues a signal which allows for clearance for production.
10. Method according to claim 9, characterised in that the tunnel temperature in the shrink tunnel (10) and/or in the at least one tunnel zone (14) is regulated or controlled by the capacity of heating means (15) which produce the tunnel temperature, in such a way that, during the normal operating mode, the tunnel temperature corresponds to a target operating temperature in the range between 190 and 210 °C, preferably a target operating temperature of 200 °C, and in the stand-by mode the tunnel temperature in the at least one tunnel zone (14) is lowered to a reduced tunnel temperature by a temperature amount (ΔT) of 50 °C to 80 °C in relation to the target operating temperature.
11. Method according to any one of claims 9-10, characterised in that the heating means (15) of the at least one tunnel zone (14) is controlled or regulated between a heating output, corresponding to the base load, of 10 KW to 14 KW and a maximum heating output of 46 KW - 50 KW.
12. Method according to any one of claims 9-11, characterised in that the stand-by mode is initiated with a time delay (Δt1), for example with a time delay in the range of 1 to 2 minutes.
13. Method according to any one of claims 9-12, characterised in that, after the initiation of the stand-by mode, a reduction takes place of the conveying speed of the shrink tunnel-side conveyor (13) to 20% to 40% of the conveying speed of the normal operating mode and/or a switching off of a cooling arrangement of the shrink tunnel-side conveying element (13) and/or a cooling arrangement which serves to cool the packing units (4) after the shrinking on of the shrink film, and/or a switching off the blower fans of the heating means (15).
14. Method according to any one of claims 9-13, characterised in that, on reaching the first temperature threshold value, the first temperature threshold value, which lies 5% to 7% below the target operating temperature, the conveying speed of the shrink tunnel-side conveyor (13) is increased again, and/or a cooling arrangement of this conveying system is switched on, and/or, on reaching the second threshold value, which lies 2% to 5% below the target operating temperature, the signal is issued which allows for clearance for production, and/or a cooling arrangement for the packaging units or containers (4) is switched on.
15. Production system with a shrink tunnel (10) downstream of a packing machine (7), characterised in that the shrink tunnel is configured in accordance with any one of preceding claims 1-8.

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