CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims foreign priority benefits under 35 U.S.C. § 119(a)-(d) to German patent application number DE 10 2020 201 284.9, filed Feb. 3, 2020, which is incorporated by reference in its entirety.

TECHNICAL FIELD

The disclosure relates to a deep-drawing packaging machine, and to a method for cooling products.

BACKGROUND

Such deep-drawing packaging machines are used to manufacture packagings in the shape of trays, where the products packaged therein are filled into the manufactured trays along a loading stretch of the deep-drawing packaging machine and the filled trays are then transported to a sealing station for sealing the trays.

If the products placed in the trays are hot products, for example pre-cooked filled pasta squares, they can be slightly cooled way of by an evacuation process carried out within the sealing station. However, it may be that the associated cooling effect is not sufficient to cool down the products to a desired temperature level prior to the sealing process, since the evacuation phase employed within the sealing station does not last long enough. Enclosing products that are too hot, however, can lead to undesirable precipitation settling inside the sealed packagings.

DE 296 07 689 U1 discloses a deep-drawing packaging machine with a sealing station having downstream in the direction of transport a mechanical cooling device which by use of cooling cushions mounted thereon presses on sealed packagings from above and below in order to cool them down after the sealing process downstream of the sealing station.

The disclosure is based on an object of providing a deep-drawing packaging machine and a method with which, in particular, products to be hot-packaged can be packaged with a uniform packaging quality and at an increased machine output rate.

SUMMARY

This object is satisfied by a deep-drawing packaging machine according to the disclosure, as well as a method according to the disclosure.

The deep-drawing packaging machine according to the disclosure comprises a forming station for deep-drawing trays into a film, a loading stretch for filling the trays with products, and a sealing station for sealing the trays. According to the disclosure, the deep-drawing packaging machine comprises at least one vacuum cooling station which is disposed in the direction of transport upstream of the sealing station and which is configured to vacuum-cool the products placed into the trays along the loading stretch. Products introduced hot can be pre-cooled to a desired (pre)temperature level already at the deep-drawing packaging machine, at a point in the direction of transport upstream of the sealing station, before they are transported to the sealing station for the sealing process. This ensures in particular that the products being hot-filled along the loading stretch are cooled prior to entering the sealing station in such a way that the evacuation process carried out within the sealing station needs to provide only a reduced cooling capacity in order to bring the products to a desired temperature level prior to the sealing process. With the disclosure, the actively controlled product cooling therefore already commences upstream of the sealing station within the separate vacuum cooling station according to the disclosure. In this way, the products can be brought to a predetermined temperature level in a particularly efficient manner, precisely and in a timed manner with regard to the sealing process.

The vacuum cooling station and the sealing station are preferably present in the form of spatially separated work stations on the deep-drawing packaging machine and are each configured to form at least one hermetically sealable evacuation chamber. In this way, cooling down the hot-filled products can be distributed selectively to different work stations, so that the products can be cooled down to a desired temperature level more efficiently due to the successive cooling effects obtained.

A variant provides that the vacuum cooling station comprises several hermetically sealable evacuation chambers which are arranged consecutively in the direction of transport. In this way, several evacuation chambers are used on the deep-drawing packaging machine upstream of the sealing station, by use of which the products passed therethrough can be cooled gradually so that the cooling process can be split over several machine work cycles. This leads to significantly increased machine output with consistent packaging quality. This allows the products to be cooled particularly gently, i.e., a little bit in every cooling chamber.

It is advantageous if the vacuum cooling station provides a separate vacuum pump. This means that the vacuum cooling station can carry out the evacuation process independently of other work stations of the deep-drawing packaging machine, quasi as a work station functioning in an autarkic manner. In particular, the operation of the vacuum pump of the vacuum cooling station is independent of the operation of a vacuum pump used at the sealing station so that the cooling process at the vacuum cooling station can be better controlled in a product-specific manner.

As an alternative to this, it would be conceivable to have the evacuation processes taking place at the sealing station and the vacuum cooling station be carried out simultaneously by way of a common vacuum pump. The sealing station and the vacuum cooling station have quasi the same vacuum pump.

A preferred variant provides that the vacuum cooling station comprises at least one filter unit for a ventilation process. The vacuum cooling station can then be ventilated using filtered air, which prevents the product from being contaminated with germs.

The sealing station and the vacuum cooling station, in particular their chamber walls, can be heated to a predetermined temperature level. In this way, precipitation of moisture on the sealing station and the vacuum cooling station can be prevented, or at least reduced.

The deep-drawing packaging machine preferably comprises at least one condenser for the selective removal of moisture. For example, moisture can be separated from the evacuated air of the sealing station and/or the vacuum cooling station in a selective manner using the condenser, which leads in particular to hygienic operation of the deep-drawing packaging machine. It is conceivable that the sealing station and/or the vacuum cooling station pass evacuation air from the respective evacuation chambers via heated lines to the condenser, where the moisture can be separated from the heated evacuation air.

The vacuum cooling station can be attached to a machine frame of the deep-drawing packaging machine upstream of the sealing station, optionally at different locations. This means that the vacuum cooling station can be used better in a flexible manner to pre-cool products filled at different temperatures. A variant provides a linear guide on the machine frame on which the vacuum cooling station is mounted such that it is displaceable in the direction of transport.

A particularly advantageous variant provides that the vacuum cooling station be configured in the form of a rollable carriage unit which can be temporarily positioned in a stationary manner on the deep-drawing packaging machine, in particular on its machine frame. This enables the mobile employment of the vacuum cooling station on the deep-drawing packaging machine. The vacuum cooling station in the form of a rollable carriage unit is particularly suitable for service and cleaning purposes.

For pretreating the products filled, the vacuum cooling station can comprise a protective gas device which is formed for subsequent gas flushing of the products that are vacuum cooled therein. This means that the products filled can be provided with a kind of gas envelope for onward transportation.

Opening and closing the vacuum cooling station can be synchronized with opening and closing the sealing station that is positioned in the direction of transport downstream thereof. It would be conceivable to have the opening and closing of the vacuum cooling station be triggered by the opening and closing of the sealing station.

The deep-drawing packaging machine preferably comprises a control unit for controlling and monitoring the processes running at the vacuum cooling station, regardless of in which form the vacuum cooling station and/or at which location the vacuum cooling station is present upstream of the sealing station on the thermoformed packaging machine. This can in particular be the same control unit that is also provided for controlling other work stations of the deep-drawing packaging machine, for example, the sealing station and/or the forming station positioned at the inlet on the machine frame for producing the trays.

With regard to a product temperature recorded along the loading stretch, one variant provides that an evacuation pressure that can be varied at the vacuum cooling station can be activated and/or an evacuation pressure curve running therein, for example, in the form of a controlled pressure curve, can be controlled. In this way, the cooling process within the vacuum cooling station can be carried out in a product-specific manner regarding the product temperatures measured, so that products with a uniform product temperature can be sealed within the sealing station. In other words, the products can therefore be fed to the sealing station at a desired product temperature, so that packagings with uniform product quality can be sealed therein.

It is conceivable that the vacuum cooling station comprises a temperature measuring unit, for example, in the form of a temperature sensor or a thermal imaging camera, with which the product temperature of a product available immediately upstream of the vacuum cooling station can be recorded, based on which the evacuation process can be controlled. Alternatively, the temperature measuring unit can be present as a separate unit upstream of the vacuum cooling station.

The disclosure also relates to a method for cooling products which are placed on trays along a loading stretch of a deep-drawing packaging machine. According to the disclosure, the products placed into trays are cooled outside a sealing station, within a vacuum cooling station of the deep-drawing packaging machine that is in the direction of transport upstream of the sealing station, by way of an evacuation process controlled thereon. In this way, the products placed into the trays reach a reduced temperature level already outside the sealing station, based on which temperature level better packagings of consistent quality can be produced by the subsequent processes carried out within the sealing station. Cooling the products upstream of the sealing station, which is actively controlled within the vacuum cooling station, already leads to an at least partial cooling effect which is favorable for the processes subsequently running within the sealing station. In particular, the products can be brought precisely to a desired temperature level until the sealing process is carried out.

