Plant for manufacturing containers from preforms

Abstract

Plant for manufacturing containers from preforms, the plant comprising a manufacturing machine for manufacturing preforms, a blow molding machine for manufacturing containers from preforms, a transport device for feeding preforms from the manufacturing machine to the blow molding machine and a storage device to which preforms can be fed from the transport device at a withdrawal point and transferred to the transport device at a transfer point, wherein the storage device includes a temperature control device for temperature control of the preforms.

Description

[0001] The present invention relates to a plant for producing containers from preforms according to claim 1 and to a method for producing containers with a plant according to claim 9. State of the art

[0002] Plants for producing containers from preforms are generally known. These can be implemented as single-stage or two-stage processes. In the single-stage process, preforms are produced in an injection molding machine and fed to a machine for producing containers from preforms (especially blow molding machines) via a conveyor system that is usually very short, allows the preforms to be handled in a defined manner, and receives a large portion of the heat from the injection molding process. In the two-stage process, the preforms are produced separately and fed, for example, via truck transport routes, to the plants that produce containers from the preforms. Here, too, a direct connection between preform production and container production is possible; however, the preform must be reheated rather than just conditioned.

[0003] In general, when blocking preform and container production, the reliable manufacture of containers depends on the manufacturing machine for producing the preforms (for example, an injection molding machine) and the blow molding machine being synchronized with each other so that they have essentially the same throughput. Otherwise, the preforms from the blow molding machine can back up or the blow molding machine can run idle. Both have a negative impact on operation and, in particular, backing up of the preforms can lead to them not being sufficiently tempered to be reliably formed into containers. Thus, both the one-stage and two-stage processes require heating or tempering of the preforms to a specific target temperature. However, due to possible variability in the preform feed, this can sometimes be difficult to achieve with sufficient accuracy. Task

[0004] Based on the known state of the art, the technical problem to be solved is to provide a plant for producing containers from preforms and a method for producing containers from preforms, with which reliable operation of the plant and, at the same time, high quality of the containers produced can be achieved. Solution

[0005] This object is achieved according to the invention by the system for producing containers from preforms according to claim 1, as well as the method for producing containers from preforms with a system according to claim 9. Advantageous developments of the invention are covered in the subclaims.

[0006] The system according to the invention for producing containers from preforms comprises a production machine for producing preforms, a blow molding machine for producing containers from preforms, a transport device for feeding preforms from the production machine to the blow molding machine and a storage device to which preforms can be fed from the transport device at a removal point and transferred to the transport device at a transfer point, wherein the storage device comprises a tempering device for tempering the preforms.

[0007] The transport device can, in principle, be designed in any desired manner. The transport device can comprise a linear conveyor (e.g., an air conveyor) and / or a number of rotating star wheels that transport the preforms from the production machine to the blow molding machine. The transport device can also comprise a sorting device that at least partially changes the spatial arrangement of the preforms after they leave the production machine, enabling them to be transferred to the blow molding machine.

[0008] A switch or a controlled rotating star wheel can be provided at the removal point and / or the transfer point, which, as required, either feeds the preforms to the storage device or moves them further in the transport device in order to feed them to the blow molding machine for producing containers from the preforms.

[0009] The storage device can enable the preforms to be stored, saved, or accumulated in an orderly or disordered manner. Orderly storage of the preforms can, in particular, involve storing the preforms in a specific spatial orientation (e.g., hanging vertically), whereas disordered storage of the preforms involves storing the preforms without a predetermined spatial orientation. The latter can be implemented, for example, in the form of a silo, a box, or another receptacle for preforms.

[0010] The tempering device may, for example, comprise one or more infrared radiators and / or microwave radiators and / or a hot air supply in order to temper the preforms, in particular to keep them at a desired temperature.

[0011] The production machine can, in principle, be any machine suitable for producing preforms from a preform starting material (e.g., PET pellets) by, for example, melting the preform starting material and introducing the molten preform starting material into a mold or tool. The production machine can, in particular, be designed as an injection molding machine, although other variants known from the prior art, such as a compression molding machine, can also be used. The invention is not limited in this regard.

[0012] With the system according to the invention, by storing the preforms and tempering them during storage, even when the blow molding machine is stopped, it can be ensured that the preforms produced by the injection molding machine do not have to be rejected as scrap, but can be returned to the conveyor system for further use. This improves the operation of the system and the quality of the produced containers, while simultaneously minimizing waste.

[0013] The removal point can be arranged upstream or downstream of the transfer point in the transport direction of the preforms in the transport device. The feeding of the preforms at a transfer point upstream or downstream of the removal point can be selected, for example, depending on the presence of a sorting device and / or the random or ordered storage of the preforms in the storage device, in order to ensure reliable feeding of the preforms to the transport device.

[0014] In one embodiment, it is provided that the system comprises a control unit for controlling the tempering device depending on a target temperature of the preforms.

[0015] The target temperature can, in particular, be a temperature that the preforms must have upon transfer to the transport device or can depend on this temperature. Alternatively or additionally, a target temperature of the preforms upon input into the blow molding machine can be selected as the target temperature, or the target temperature can depend on how high the temperature of the preforms must be upon feed to the blow molding machine. The target temperature can then be determined, for example, taking into account the transport route and the expected cooling of the preforms during transport. The temperature control device can then be controlled with regard to the power or heat it outputs so that the target temperature of the preforms in the storage device is reached. This improves the quality of the containers produced from the stored preforms.

[0016] In particular, it can be provided that the system comprises a sensor for determining a temperature of preforms in the transport device, and wherein the target temperature depends on the determined temperature and / or on requirements for producing containers from the preforms using the blow molding machine. The requirements for producing the containers from the preforms using the blow molding machine can include, for example, a required temperature of the preforms when feeding the preforms to the blow molding machine and / or a heating device (oven) of the blow molding machine. These requirements can be used, for example, in addition to or alternatively to the determined temperature to determine the target temperature of the preforms.For example, extrapolating the cooling of the preforms from the transfer point to the point where the preforms are transferred to the blow molding machine can be used to determine the target temperature based on the temperature to be reached by the preforms when the preforms are transferred to the blow molding machine.

[0017] The sensor can, in particular, be a thermal sensor that can determine the temperature of preforms (for example, based on infrared radiation emitted by the preforms and / or a radiation spectrum of the preforms). In principle, the temperature of the preforms in the transport device can be determined at any point along the transport device, and the target temperature can be dependent on this specific temperature. This ensures that the temperature of the preforms returned to the transport device corresponds to the temperature of the preforms transported in the transport device, so that the result in the production of the containers is as consistent as possible.

[0018] The sensor can be arranged so that it can determine the temperature of the preforms in a region of the transfer point. With this embodiment, the target temperature of the preforms can preferably be selected so that it corresponds to the temperature of the preforms in the transport device at the transfer point, so that all preforms have the same temperature at the transfer point, regardless of whether they are fed from the storage device to the transport device or are transported in the transport device. The containers can thus be manufactured from the preforms with consistent quality.

[0019] The area of ​​the transfer point is to be understood here as an area in the transport device that can extend around the transfer point. The sensor can preferably be arranged such that it can determine the temperature of the preforms directly at the transfer point or in an area that extends, for example, up to 10, 20, or 50 cm upstream or downstream of the transport device. Several sensors can also be provided, arranged one after the other in the transport direction of the preforms, in order to determine not only the temperature of the preforms at a specific point, but also a temperature profile of the preforms during transport. This temperature profile can also be used instead of the determined temperature to define the target temperature, which may be possible with greater accuracy.

[0020] The control unit can be designed to control the tempering device such that the preforms have the target temperature at a transfer time.

[0021] If, for example, it is intended that the preforms are transferred from the storage device to the transport device at a specific time (the transfer time or the transfer time), the tempering device can be switched on and / or switched off and / or controlled with regard to its performance in such a way that the preforms have the target temperature when the transfer time is reached.Since the preforms are usually fed to the storage device at different times, the temperature control device can either be controlled in such a way that the preforms have the desired target temperature on average (on average over the temperature of a large number of preforms that are located in the storage device at the same time but were fed to it at different times) or the temperature control device can be designed in such a way that it can temperature-control preforms fed in at different times differently, for example by providing several independently controllable heaters that can heat specific areas of the storage device to which the preforms are fed depending on their feed time to the storage device.This allows energy to be saved because the temperature control device can be controlled so that only the heat energy required to reach the target temperature is released.

[0022] It can be provided that the control unit is designed to control the tempering device depending on a planned end of operation of the production machine such that the preforms have the target temperature at the planned end of operation.

[0023] The planned end of operation can, for example, be a time when a container type is changed, a maintenance interval, or another interruption in the operation of the production machine. In this case, the end of operation of the production machine is not synonymous with the end of operation of the system, but simply means that the production machine is no longer producing any more preforms. However, since preforms may still be present in the storage device, they can be further processed by the blow molding machine after the production machine has shut down. This simplifies the feeding of the preforms from the storage device to the transport device during operation and simultaneously minimizes waste, since the preforms are preferably completely formed into containers.

[0024] The system can be designed in such a way that the preforms are fed to the transport device from the storage device when there are no more preforms in the transport device upstream of the transfer point.

[0025] After the machines have shut down, the preforms from the production machine continue to be fed to the blow molding machine without any new preforms being added. This means that for a certain time after the production machine has shut down, there are no more preforms upstream of the transfer point, allowing the preforms from the storage device to be fed unhindered to the transport device.

[0026] According to the invention, a method for producing containers from preforms is further provided with a system, the system comprising a production machine for producing preforms, a blow molding machine for producing containers from preforms, a transport device for feeding preforms from the production machine to the blow molding machine and a storage device to which preforms can be fed from the transport device at a removal point and transferred to the transport device at a transfer point, wherein the storage device comprises a tempering device for tempering the preforms, the method comprising feeding preforms from the storage device to the transport device when there are no preforms upstream of the transfer point, at least temporarily.

[0027] This process enables reliable production of containers from preforms while simultaneously reducing waste.

[0028] The removal point can be arranged upstream or downstream of the transfer point in the transport direction of the preforms in the transport system. The arrangement of the removal point and transfer point can be selected according to practical requirements to ensure reliable operation of the system.

[0029] The system can be provided with a control unit that controls the temperature control device depending on a target preform temperature. This ensures reliable production of containers from preforms from the storage device.

[0030] Furthermore, it can be provided that the system comprises a sensor for determining a temperature of preforms in the transport device and wherein the target temperature is dependent on the determined temperature, wherein optionally the sensor is arranged such that it determines the temperature of the preforms in a region of the transfer point.

[0031] This embodiment ensures the consistent quality of the containers produced from preforms, regardless of whether they are fed directly from the production machine to the blow molding machine or whether they are temporarily stored in the storage device.

[0032] In one embodiment, the control unit controls the temperature control device so that the preforms are at the target temperature at a transfer time. This allows the energy required for temperature control of the preforms to be reduced.

[0033] The control unit can be configured to control the temperature control device depending on the planned end of operation of the production machine so that the preforms are at the target temperature at the planned end of operation. This allows for a smooth feeding of the preforms stored in the storage device to the transport device.

[0034] The control unit can determine the end of operation based on the number of preforms in the storage device and / or based on the number of containers to be produced. This embodiment can ensure that sufficient containers are produced while simultaneously minimizing waste. Short description of the characters Fig. 1 shows a schematic view of a system according to an embodiment. Fig. 2 shows a flow chart of a method for controlling the tempering device to achieve a target temperature of the preforms. Fig. 3 shows a flow chart of a method for controlling the tempering device and for feeding the preforms to the storage device at an end of operation of the manufacturing machine. Detailed description

[0035] Fig. 1 shows a system for producing containers 132 from preforms 130.

[0036] The system comprises a production machine 101 with which preforms 130 can be produced. The production machine 101 can, for example, be designed as an injection molding machine in which heated preform starting material (for example, PET) is fed to a tool in which the preforms are formed by injecting the heated preform starting material. The preforms can then optionally cool and be removed from the tool. Instead of an injection molding machine, an injection molding machine or a compression molding machine can also be used as the production machine. All of these machines are basically known from the prior art and will not be described further here with regard to their further design. The invention is fundamentally not limited with regard to the design of the production machine.

[0037] The system 100 further comprises a blow molding machine 102 for producing containers 132 from the preforms 130. The blow molding machine 102 can, for example, be designed as a stretch blow molding machine and, through the action of compressed air and / or a stretching rod in the interior of the preform, cause the preform to expand so that its outer surface contacts the inner wall of a blow mold of the blow molding machine. Corresponding blow molding machines are well known in the art, and the blow molding machine 102 can, in particular, be designed as a rotary machine with a carousel that is mounted for rotation about a rotation axis and on whose periphery a number of blow molds are arranged for receiving and forming preforms into containers. However, the invention is not limited in this regard, and any blow molding machine with which containers can be produced from preforms can be provided.

[0038] According to the invention, a transport device 103 is provided, by which the preforms are fed from the production machine 101 to the blow molding machine 102. The transport device 103 can, in principle, be designed in any desired manner. In particular, the transport device 103 can comprise an air conveyor, by means of which the preforms are transported, for example, suspended from their support ring between air conveyor rails and transported in the direction of the blow molding machine by generating a compressed air flow. Alternatively or additionally, a conveyor inclined downwards in the transport direction (in the direction of gravity) can also be provided, in which the preforms can be transported solely or essentially due to the force of gravity acting on them.Alternatively or additionally, one or more rotating star wheels can be provided, which can pick up the preforms, for example, using individually operable clamps on the circumference of the rotating star wheels, and transport them from the production machine 101 toward the blow molding machine. Also conceivable are transport devices that transport preforms using electromagnetic forces. In particular, long stators with movers arranged thereon that can transport one or more preforms can be provided. Combinations of these or other transport devices can also be provided, enabling the preforms to be transferred from the production machine to the blow molding machine 102.

[0039] Optionally, a sorting device 131, shown only schematically here, can be arranged either in the area of ​​the transport device or as part of the production machine 101. This sorting device sorts the preforms coming from the production machine 101. The sorting of preforms refers to any manipulation of the arrangement of the preforms that imposes a new orientation or arrangement on the preforms starting from an initial orientation or arrangement (which may be ordered or disordered, in particular random or chaotic).If the preforms are produced in the production machine 101, for example, in a regular pattern in the form of a two-dimensional matrix in a tool and then transferred to a random supply, the sorting device 131 can be designed such that, after receiving the random preforms, it aligns the preforms so that they are transferred to the transport device 103, for example, all hanging from their support ring and aligned so that the opening area of ​​the preform faces upwards. For this purpose, it can be provided that the transport device 103 is designed, for example, in two parts, with a first part of the transport device extending from the production machine 101 to the sorting device 131. This part of the transport device can, for example, enable random transport of preforms coming from the production machine and can be designed, for example, as a conveyor belt.In the sorting device 131, these preforms can then be sorted and subsequently fed with the intended orientation to a second part of the transport device 103, which can then be designed, for example, as an air conveyor and / or comprising one or more rotary stars.

[0040] The sorting device is designed to enable transfer to the second part of the transport system. Such sorting devices are generally known from the prior art and include, for example, roller sorters or disc sorters.

[0041] The blow molding machine 102 can optionally also comprise a heating device arranged upstream of a blow molding area in which the preforms are formed into containers. The heating device can comprise one or more heaters, for example infrared heaters or microwave heaters, which can temper the preforms to a specific temperature after they have been transferred to this heating device from the transport device 103. In this case, the imprinting of a desired temperature profile (a temperature progression, for example, along the length of the preform) into the preform can also be provided.

[0042] According to the invention, the system 100 further comprises a storage device 104 to which preforms can be fed. This occurs by removing the preforms from the transport device 103 at a removal point 141 and feeding them, for example, via a suitable transport device 143, to the storage device 104. The transport device 143 (also discharge transport device) is connected to the transport device 103 in such a way that preforms can preferably be selectively removed from the transport device 103 at the removal point 141 and fed to the transport device 143. This can be achieved, for example, by arranging a switch in an air conveyor for conveying the preforms as the transport device 103, so that a branching of the air conveyor towards the storage device 104 is possible at the removal point 141.If the switch is switched and / or a blocking element is actuated to block the transport device 103 downstream of the switch, the preforms can be diverted into the transport device 143.

[0043] If the transport device 103 is designed as a series of rotating stars, it can be provided that a rotating star in the removal point 141 can be controlled in order to either transfer the preforms to a subsequent rotating star in the transport direction towards the blow moulding machine 102 or to transfer the preforms to a rotating star of the transport device 143 so that they can be fed to the storage device 104.

[0044] Furthermore, it is provided that preforms can be fed again from the storage device 104 to the transport device 103 at a transfer point 142. For this purpose, a further transport device 144 (also referred to as a feed transport device) can be provided, analogous to the transport device 143, which can remove the preforms from the storage device 104 and feed them to the transport device 103 at the transfer point 142. This can be implemented analogously to the design of the transport device 143 at the removal point 141.Alternatively, it can be provided, for example, that in the event that the transport device 103 is provided upstream of a sorting device 131 as a device for the random transport of the preforms, the further transport device 144 is also designed for the random transport of the preforms from the storage device 104, for example as a chute on which the preforms can be conveyed along a gradient from the storage device 104 in the direction of the transfer point 142.

[0045] The storage device 104 can be designed for the orderly or disordered storage or warehousing of preforms. If the storage device 104 is designed for the orderly storage of preforms, the storage device can be designed, for example, as a storage rail or as a buffer system in which the preforms are held with a specific orientation. If the storage device 104 is designed for the storage of preforms in the form of a disordered supply, it can be provided that the storage device comprises, for example, a receiving container, such as a silo or the like, to which the preforms are fed and in which they are stored in a disordered manner or without any imposed order. In this embodiment, it is particularly advantageous if the further transport device 144 is designed for the disordered transport of the preforms.

[0046] According to the invention, the storage device comprises a tempering device 105 for tempering the preforms in the storage device 104. The tempering device 105 can, for example, comprise one or more microwave radiators or infrared radiators or also comprise a warm air blower with which the preforms can be subjected to thermal energy.

[0047] In the Fig. 1, the removal point 141 is located downstream of the transfer point 142. However, this is not mandatory. The removal point 141 can also be arranged upstream of the transfer point 142, viewed in the transport direction of the preforms in the transport direction 103. The distance between the transfer point and the removal point is not limited according to the invention, but preferably extends such that, if a sorting device 131 is provided, the removal point is arranged downstream of the sorting device in the transport device 103 and the transfer point is arranged upstream of the sorting device 131 in the transport direction of the preforms in the transport device 103. This makes it possible for the preforms fed from the transport device 103 to the storage device to be stored in an unsorted manner in the storage device. This can facilitate the storage of the preforms.

[0048] Optionally, a control unit 180, for example in the form of a computer with associated memory and processor, can be provided as part of the system, which can be designed to control the temperature control device 105 and / or the removal of preforms from the transport device 103 to the storage device 104 and / or the feeding of preforms to the transport device from the storage device. This can, for example, comprise the control unit controlling the temperature control device depending on certain further parameters, for example a (target) temperature to be achieved by the preforms when they are transferred to the transport device from the storage device, or the tempering of the preforms to a temperature which they are to assume at the end of operation of the production machine. This will be explained in more detail with regard to the Fig. 2 and Fig. 3 more described.

[0049] To enable control of the temperature control device 105 by the control unit 180, one or more sensors 161 to 163 can be arranged in the region of the transport device 103 to determine the temperature of the preforms in the transport device. Optionally, a further sensor 164 can also be provided in the region of the storage device to determine the temperature of the preforms in the storage device 104. Instead of one sensor 164 in the region of the storage device 104, a plurality of sensors 164 can also be provided in the storage device 104 to enable precise measurement of the temperature of all preforms in the storage device. This can be particularly advantageous in the case of random storage of the preforms in the storage device.

[0050] In one embodiment, it is particularly advantageous if the one or more sensors 161 to 163 for determining the temperature of the preforms in the transport device 103 are arranged in a region 160 of the transfer point 142 such that they can determine the temperature of the preforms in the transport device 103 in this region 160. This can be advantageously used to determine the temperature of the preforms in the transfer point or in the region 160, and the control unit 180 can be configured to control the temperature control device 105 based on this temperature such that the preforms transferred from the storage device of the transport device 103 at the transfer point have substantially the same temperature as the preforms 130 at the transfer point.

[0051] The fact that the preforms have essentially the same temperature can mean that the preforms either have an identical temperature or a temperature difference of up to + / - 0.2K or up to + / - 0.5K, compared to the preforms in the transport device 103, is permissible for the preforms fed to the transport device 103. Based on this, the temperature control device 105 can then be controlled by the control unit 180 such that the preforms have the desired target temperature. This can either already be identical to the temperature of the preforms in the transport device 103 or slightly higher, for example, to compensate for heat loss from the preforms during transport from the storage device to the transfer point.

[0052] Fig. Figure 2 shows a flow diagram of an embodiment of a method for controlling the temperature control device based on the transfer time of the preforms from the storage device to the transport device. This method can be implemented with the system according to any of the methods associated with Fig. 1 described embodiments.

[0053] The method first comprises determining a desired transfer time of preforms from the storage device to the transport device. This transfer time can be based, for example, on a break or production interruption of the manufacturing machine 101 (see Fig. 1) or be determined based on a gap in the flow of preforms in the transport device 103. In addition, in step 202, the temperature of the preforms in the transport device, in particular at the transfer point (see Fig. 1) can be determined.

[0054] Based on the determined transfer time and / or the determined temperature of the preforms in the transport device in steps 201 and 202, a target temperature of the preforms in the storage device can then be determined in step 203, for example by the control unit 180. This target temperature will usually be greater than, but at most equal to, the temperature of the preforms in the transport device (for example, at the transfer point) and can be determined by the control unit not only as a function of the determined transfer time and / or the determined temperature of the preforms in the transport device, but can also be based, for example, on further information available to the control unit, such as an ambient temperature or an expected heat loss of the preforms after leaving the storage device.

[0055] Once the target temperature has been determined, the temperature control device 205 can then be controlled such that the preforms are heated to the target temperature. For this purpose, the temperature control device can be controlled in step 205, for example, such that it can heat the preforms to the target temperature within the time still available until the transfer time. This can be ensured either by the control unit controlling the temperature control device to deliver a predetermined amount of heat per unit of time or by a control loop. This control loop can include, in step 204, first determining a temperature of the preforms in the storage device and optionally comparing it with the target temperature.Based on the temperature difference between the preforms in the storage device and the target temperature, as well as taking into account the time remaining until the transfer point, the control unit can then determine how much heat needs to be transferred to the preforms in this time to heat them to the target temperature. The temperature control device can then be controlled based on this.

[0056] After a certain time has elapsed (e.g., a few seconds or minutes), the temperature of the preforms in the storage device can be determined again. By checking the preform temperature, the temperature control device can be further controlled to heat the preforms more quickly or more slowly, if necessary. Depending on the fill level of the storage device, for example, increased heat output from the temperature control device may be necessary to heat the preforms in the storage device to the desired temperature within the specified time until the transfer point. This can be accommodated by the described control loop.

[0057] Once the preforms have reached the target temperature, they can be transferred to the transport device at the transfer time (206).

[0058] Fig. Figure 3 shows a further embodiment of a method for controlling the tempering device and transferring the preforms to the transport device for producing containers from these preforms. In this embodiment, an operating end of the production machine (see Fig. 1). A certain number of containers are to be produced simultaneously.

[0059] In this embodiment, method 300 begins in step 301 by determining the number of containers to be produced. This number of containers to be produced can, for example, be a remaining number of containers to be produced. For example, if a total number of 150,000 containers is required for an order, and 100,000 containers have been produced so far, the production of an additional 50,000 containers is required.

[0060] Since preforms are not only fed from the production machine upstream of the blow molding machine but can also be available in the storage device, the number of preforms in the storage device and the number of preforms in the transport device can be determined in steps 302 and 303. Based on this number, it can be determined whether further preforms need to be produced by the production machine. If the total number of preforms in the storage device and the transport device according to steps 302 and 303 is, for example, 25,000, then a further 25,000 preforms still need to be produced by the production machine. While steps 302 and 303 are shown one after the other here, it is also conceivable that these steps could be carried out simultaneously or in a reversed order.

[0061] In step 304, an end of operation of the production machine is determined based on the number of containers to be produced and / or the number of preforms in the storage device and / or the number of preforms in the transport device. This end of operation defines when the production machine stops producing preforms. The time until this end of operation can, for example, be specified as a multiple of an operating cycle, where an operating cycle comprises exactly one production cycle of the production machine. Alternatively, the time until the end of operation can also be represented as a time interval (e.g., minutes or hours).

[0062] In this embodiment, it is provided that upon reaching the end of operation, no further preforms are produced by the production machine, and instead, the preforms still remaining in the transport device and / or present in the storage device are fed to the blow molding machine. For this purpose, it can be particularly advantageously provided that upon reaching the end of operation, and in particular upon emptying the transport device up to the transfer point, preforms are fed from the storage device to the transport device, since no further preforms follow from the direction of the production machine, thus allowing unhindered transport of the preforms from the storage device to the transport device.

[0063] Depending on this point in time at which the operation ends and / or the emptying of the transport device up to the transfer point, the temperature control device can then be controlled in step 306 so that the preforms in the storage device have a desired temperature (target temperature) upon reaching the end of operation. Optionally, in step 305, analogous to step 204, the Fig. 2 the temperature of the preforms in the storage device can be determined in order to then control the temperature control unit based on this.

[0064] Since the feeding of preforms to the storage device can also take place during operation, for example if the blow molding machine fails unintentionally, it can be provided that steps 302 to 306 are carried out again in the form of a control loop, wherein the number of preforms in the storage device and the remaining number of preforms in the transport device are determined at regular intervals in order to determine the end of operation and based on this and optionally the preform temperatures of the storage devices, the controller controls the temperature control devices.

[0065] In step 307, upon reaching the end of operation and / or after the transport device has been emptied to the transfer point, the preforms are transferred from the storage device to the transport device, wherein they then have the desired temperature. It is understood that the target temperature of the preforms can be determined, for example, based on the method of Fig. 2 can be determined.

Claims

[1] Plant for producing containers from preforms, the plant comprising a production machine (101) for producing preforms, a blow molding machine (102) for producing containers from preforms, a transport device for feeding preforms from the production machine to the blow molding machine and a storage device (104), to which preforms can be fed from the transport device at a removal point (141) and transferred to the transport device at a transfer point (142), wherein the storage device (105) comprises a tempering device for tempering the preforms. [2] Plant according to claim 1, wherein the removal point is arranged upstream or downstream of the transfer point in the transport direction of the preforms in the transport device. [3] Plant according to claim 1 or 2, wherein the plant comprises a control unit for controlling the tempering device depending on a target temperature of the preforms. [4] Plant according to claim 3, wherein the plant comprises a sensor for determining a temperature of preforms in the transport device and wherein the target temperature is dependent on the determined temperature and / or on requirements when producing containers from the preforms with the blow molding machine. [5] Plant according to claim 4, wherein the sensor is arranged so that it can determine the temperature of the preforms in a region of the transfer point. [6] Plant according to one of claims 3 to 5, wherein the control unit is designed to control the tempering device so that the preforms have the target temperature at a transfer time. [7] Plant according to one of claims 1 to 6, wherein the control unit is designed to control the tempering device depending on a planned end of operation of the production machine so that the preforms have the target temperature at the planned end of operation. [8] Plant according to claim 7, wherein the plant is designed such that the preforms are fed to the transport device from the storage device when there are no more preforms upstream of the transfer point in the transport device. [9] A method for producing containers from preforms using a system, the system comprising a manufacturing machine for producing preforms, a blow molding machine for producing containers from preforms, a transport device for feeding preforms from the manufacturing machine to the blow molding machine and a storage device to which preforms can be fed from the transport device at a removal point and transferred to the transport device at a transfer point, wherein the storage device comprises a tempering device for tempering the preforms, the method comprising feeding preforms from the storage device to the transport device when there are at least temporarily no preforms upstream of the transfer point. [10] Method according to claim 9, wherein the removal point is arranged upstream or downstream of the transfer point in the transport direction of the preforms in the transport device. [11] Method according to claim 9 or 10, wherein the system comprises a control unit which controls the tempering device depending on a target temperature of the preforms. [12] Method according to claim 11, wherein the system comprises a sensor for determining a temperature of preforms in the transport device and wherein the target temperature is dependent on the determined temperature, optionally wherein the sensor is arranged to determine the temperature of the preforms in a region of the transfer point. [13] Method according to claim 11 or 12, wherein the control unit controls the tempering device so that the preforms have the target temperature at a transfer time. [14] Method according to claim 13, wherein the control unit controls the tempering device depending on a planned end of operation of the manufacturing machine such that the preforms have the target temperature at the planned end of operation. [15] A method according to claim 13 or 14, wherein the control unit determines the end of operation based on a number of preforms in the storage device and / or based on a number of containers to be produced.

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