SEALING TOOL FOR A SKIN PACKAGING

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage entry of PCT/EP2023/077415 filed on Oct. 4, 2023, which claims priority to DE 10 2022 210 468.4 filed on Oct. 4, 2022, the entireties of which are all incorporated by reference herein for all purposes.

FIELD

The present invention relates to an upper tool for a sealing station of a packaging machine, having an indentation with which an upper film web can be formed and having a plurality of gas through-openings that are provided along the indentation and can be connected to a negative pressure, positive pressure, and/or aeration source. Moreover, the present invention relates to a packaging machine and to a method for producing skin packaging.

BACKGROUND

In skin packaging, the upper film web is positioned directly against the packaging contents, follows at least some of the contour thereof, and is connected across a large surface area to the packaging tray on which the packaging contents are disposed. Frequently the product does not lie flat enough against the packaging products, however.

SUMMARY

It was therefore the object of the present invention to provide an upper tool with which the drawbacks of the prior art may be overcome.

The object is attained with an upper tool for a sealing station of a packaging machine having an indentation with which an upper film web can be formed and having a plurality of gas through-openings that are provided along the indentation and can be connected to a negative pressure, positive pressure, and/or aeration source, wherein gas through-openings can be divided into at least two groups that can be connected independently of one another to the negative pressure, positive pressure, and/or aeration source.

The statements provided regarding this subject matter apply equally to the further subject matters of the present invention and vice versa. Features disclosed in connection with this subject matter of the present invention may be combined with further subject matters and vice versa.

The present invention relates to an upper tool having at least one indentation into which an upper film is suctioned and thereby formed. One, two, three, four, or more packaging trays may be sealed, in particular gas-tight, with the upper film that is formed in an indentation. Using a surrounding housing/clamping tool that is preferably present, the upper film is preferably fixed during forming and/or the surrounding housing/clamping tool seals the space. The inventive upper tool is preferably heated. During forming, the originally flat film web conforms to the contour of the indentation and is heated, in particular using heat conduction.

According to the invention, the upper tool has a plurality of gas through-openings, in particular bores, in the region of the indentation and/or is made of a porous material so that it is gas permeable. The gas through-openings can be connected to a negative pressure, positive pressure, or aeration source. A negative pressure that draws the upper film into the indentation, thereby forming it, may be generated between the indentation and the upper film with the negative pressure source. The negative pressure may be reduced to approach ambient pressure and/or the upper film web may be pressed towards the packaging contents with the positive pressure and/or aeration source. Preferably only an aeration source, and no positive pressure source, is used, however.

Furthermore, according to the invention the gas through-openings can be divided into two groups that can be connected independently of one another to the negative pressure, positive pressure, and/or aeration source. The two groups are preferably divided into regions, a central region, and an edge region surrounding this central region, in particular in a ring shape. For example, the negative pressure with which the upper film web has been suctioned towards the indentation may be maintained in the edge region, while in the central region the gas through-openings are already connected to an aeration source in order to reduce, in particular partially reduce, the negative pressure. Because of this, the upper film web loosens in the central region and takes on a different shape from that of the indentation, while remaining positioned against the edge region.

The central region may have, for example, a round, oval, square, or rectangular circumference. The edge region is preferably ring-shaped, wherein the shape of the ring is preferably adapted to the central region. The central region is preferably the geometric center of the indentation. The edge region surrounds the central region, preferably as a ring.

Preferably one or a plurality of packages may be produced with one upper tool.

The upper film conforms completely to the packaging contents due to the inventive upper tool.

Preferably the upper tool has chambers that are preferably upstream with respect to the gas flow during aeration. Each chamber delimits the gas through-openings of one group. Each chamber preferably has one circumferential wall and one bottom region and one cover region. The gas through-openings of each group are provided in the bottom region. The bottom region is preferably the wall of the indentation. The cover region is preferably sealed gas-tight and/or has a connection to the negative pressure, positive pressure, and/or aeration source for that specific group.

Pressure, in particular the negative pressure, and/or the aeration in the chamber is preferably controlled by means of a valve. The gas volume flow may preferably be controlled using the valve. It is preferably possible to switch between the sources using the valve, in particular between the negative pressure source and the aeration source. At least the chamber in the central region, but preferably also the chamber in the edge region, has a valve that can be controlled in particular individually and is connected on the gas side to negative pressure, positive pressure, and/or aeration source, in particular the aeration source.

Preferably one group and/or one chamber are provided in one central region, in particular in the indentation. The central region is preferably the geometrical center of the indentation.

According to one preferred embodiment of the present invention, a further chamber, in particular a ring-shaped chamber, extends about the chamber in the central region. Ring-shaped in the context of the invention does not necessarily mean circular. The ring may have any shape familiar to the person skilled in the art, wherein a square or rectangular ring-shaped chamber is preferred.

The upper tool preferably has a pressure sensor, in particular in the central region. The pressure sensor measures the pressure between the indentation and the upper film. The signal of the pressure sensor is used in particular for initiating aeration of the ring-shaped region. A negative pressure, the product vacuum, is preferably generated in the product region, i.e. between the lower material web and the upper film, in particular during the forming of the upper film and/or during the aeration of the volume between the indentation and the upper film, preferably in that this volume is connected to a negative pressure source. The product vacuum is preferably not maintained during the aeration of the volume between the indentation and the upper film.

Preferably a negative pressure is also applied below the packaging tray, the so-called lower vacuum, in particular to prevent the packaging tray from being deformed by the product vacuum.

Preferably a non-heated flat upper film is deformed in the inventive upper tool. The entire surface of the upper film conforms to the indentation of the upper tool and is heated uniformly thereby. Since the upper film is preferably not pre-heated or pre-stretched, the energy required during production of a skin pack is relatively low. A conventional packaging machine may be converted to a “skin packaging machine” in a simple manner using the inventive upper tool in that the conventional upper tool is replaced by the inventive upper tool.

The conversion is preferably made possible by the modular design of the upper tools and is preferably carried out in the context of a rapid tool change, for example using a tool design as described in WO 2013127963 A1 by the present applicant, in which the upper tool remains on the packaging machine and only the tool insert therein, that is, the upper tool, is changed. The inventive upper tool may thus be retrofitted to existing packaging machines. The person skilled in the art understands that in this case the upper tool may be a tool for skin packs or a conventional tool, for example for so-called “modified atmosphere packagings” (MAP) or vacuum packages or simple packages without a modified atmosphere and permits the user of the packaging machine to package a variety of products with different applications. Each of these tools may be easily installed in the packaging machine so that the latter can be used in a number of ways.

One further inventive or preferred subject matter of the present invention is a packaging machine in which a packaging tray is filled with packaging contents in a filling station and which has a sealing station in which the packaging contents are enclosed with an upper film at least essentially in a form fit and the upper film bonds to the packaging tray, wherein the sealing station has an upper tool according to one of the preceding claims.

The statements made regarding this subject matter apply equally to other subject matters of the present invention and vice versa. Feature disclosed in connection with this subject matter of the present invention may be combined with other subject matters and vice versa.

This subject matter of the present invention relates to a packaging machine in which a packaging tray is provided. This may be carried out by molding the packaging tray into a flat material web or by providing a pre-made packaging tray. The packaging tray in the context of the invention also does not have to be deep-drawn at all. The material web may be a film, cardboard, or other material. The inventive packaging machine may be, for example, a so-called thermo-former or even a so-called tray sealer. In a next step, this packaging tray is filled with packaging contents, in particular a food product, preferably a protein-containing food product. The packaged contents may project beyond the upper edge of the packaging tray. According to the invention, the packaging machine has a sealing station in which the packaging contents are enclosed by an upper film at least essentially in a form fit. The person skilled in the art calls packagings in which the packaging contents are provided in a comparatively rigid packaging tray and in which the packaging contents are enclosed by an upper film essentially in a form fit a so-called skin pack. The upper film bonds to the packaging tray, preferably over a large surface area, particularly preferably over a very large surface area, in particular to the entire surface of the packaging tray that faces the upper film and is not covered by the packaging contents.

The packaging machine preferably works in cycles, wherein a plurality of packagings are produced simultaneously in one cycle.

The sealing station has the inventive upper tool. Moreover, the inventive packaging machine has a control with which it is possible to act upon the individual groups of gas through-openings independently of one another at different pressures, in particular negative pressures, and/or to aerate the individual groups differently, i.e., to reduce the negative pressure differently. To this end, the inventive packaging machine has, for example, valve(s) that can be controlled individually and that connect each group, for example, to a negative pressure source and/or to an aeration source. With this valve, it is particularly preferred that not only is an on/off control possible, but it is also possible to control the volume flow of gas from and/or to each group of gas through-openings. Evacuation of the space between the indentation and the upper film web is preferably accomplished simultaneously with all gas through-openings.

The upper tool can have a sealing frame that additionally provides a sealing seam between the upper film and the packaging tray and extending along the entire circumference of the packaging tray after and/or during the skin sealing. This at least ensures that the upper film is tightly bonded to the packaging tray at every point around the circumference and that any folds are mostly ironed out, at least in the region of the sealing seam, and cannot lead to leaks. The packaging also frequently looks more attractive after this.

A further subject matter of the present invention relates to a method for producing a skin pack in which:

• • a packaging tray having packaging contents (16) is provided;
  • an upper film web is drawn into an indentation of an upper tool by means of negative pressure;
  • a product vacuum is applied in the region of the packaging tray and packaging contents;
    • the upper film web is then formed in the direction of the packaging tray filled with packaging contents, thereby enclosing the packaging contents and bonding to the packaging tray over a large surface area;
      and in which, for forming the upper film web in the direction of the packaging tray filled with packaging contents, the negative pressure between the indentation and the upper film web is first reduced only in a central region, in particular using aeration.

The statements provided regarding this subject matter apply equally to the further subject matters of the present invention and vice versa. Features disclosed in connection with this subject matter of the present invention may be combined with further subject matters and vice versa.

With the inventive method, a skin pack is produced, i.e., a packaging in which the upper film tightly encloses the packaging contents and is bonded over a large surface area to the packaging tray. Large surface area in the context of the invention means that the sealing surface is greater than for sealing with a sealing frame. According to the invention, the upper film is formed in an upper tool of the sealing station, which has an indentation. Upstream of the upper tool, the upper film is not preformed with respect to its movement direction, but instead is flat. The upper film is not formed until it is in the upper tool, and then preferably the entire segment of upper film that will be part of the resulting packaging is heated. For forming, a negative pressure is generated between the upper tool, in particular the indentation, and the upper film, and draws the upper film towards the indentation of the upper tool, in particular until it is positioned thereagainst.

Preferably a certain waiting period is provided before the negative pressure that draws the upper film into the indentation is applied.

During and/or after the upper film has been formed in the upper tool, a negative pressure, the so-called product vacuum, is generated between the upper film and the packaging tray and preferably also below the film packaging tray. As soon as or after the upper film has been formed in the indentation, the negative pressure above the upper film is reduced and due to the negative pressure below the upper film the latter is drawn towards the packaging contents and encloses the latter in a form fit, at least in part. Since the upper film has preferably been heated in the indentation of the upper tool, it bonds to the packaging tray over a large surface area and in a material fit, preferably along the entire surface of the packaging tray that faces the upper film and that is not covered by the packaging contents. This seal is preferably peelable.

Preferably sealing is also carried out between the upper film and the packaging tray using a sealing frame and/or the upper tool This sealing preferably extends along a horizontal surface along the edge of the packaging. This sealing may be peelable.

According to the invention, negative pressure is reduced only locally between the indentation and the upper film in the central region of the indentation, while in the remaining regions of the used for forming the upper film and/or for maintaining contact between indentation and upper film is not reduced. The rest of the volume between indentation and upper film, the edge region, is not aerated until after a certain period of time has passed and/or a certain reduction in negative pressure in the central region has taken place.

The negative pressure for forming the upper film is preferably <50 mBar, preferably 10-20 mBar.

A preferred time period is <1 sec., particularly preferably <0.5 sec., and even more preferably <0.25 sec. The aeration of the remaining volume between indentation and upper film is preferably initiated when the negative pressure in the central region is preferably reduced by >40 mbar, particularly preferably >60 mbar, even more preferably >100 mbar, and most preferably >200 mbar.

The volume flow of the, in particular of the central region, is controlled during aeration. The volume flow is initially lower and is then preferably increased in a pressure-controlled manner.

The aeration of the remainder of the volume between indentation and upper film is preferably carried out as rapidly as possible without any throttling and preferably essentially, particularly preferably exclusively, via gas through-openings in the remainder of the volume between indentation and upper film, the so-called edge region.

The upper film initially preferably is positioned against the packaging tray in the central region and then against the remainder. The central region of the packaging tray is the geometric center of the region that is covered with the by the indentation of the upper film. It is preferably disposed below the highest point of the indentation.

After the central region has been aerated, the upper film forms an M shape and/or has an indentation that arches away from the indentation.

The sequence of the reduction in negative pressure in the central region and in the edge region is pressure-controlled and/or time-controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in the following using FIGS. 1-6. These explanations are merely exemplary in nature and do not limit the general inventive thought. The explanations apply equally to all of the inventive subject matters of the present invention.

FIG. 1 depicts the inventive packaging machine.

FIG. 2a depicts the shaping of the upper film.

FIG. 2b depicts the aeration during production of a skin packing method according to the prior art.

FIGS. 3a and 3b depict two alternatives for the inventive upper tool.

FIGS. 4a and 4b depict the “skinning” of the upper film.

FIG. 5 depicts an optional sealing of the edge region of the packaging.

FIGS. 6 and 7 depict the “skinning” of the upper film.

DETAILED DESCRIPTION

FIG. 1 depicts an embodiment of the inventive packaging machine 1, in this case having a deep draw station 2, a filling station 7, and a sealing station 15. A material web 8, in this case a plastic film web 8, the so-called lower material web, is drawn from a supply roll and transported from right to left, preferably in cycles, along the inventive packaging machine. In one cycle the material web 8 is transported further by one format length. To this end, the packaging machine has two transport means, in the present case two continuous chains that are arranged to the right and left of the material web. Both at the beginning and at the end of the packaging machine, at least one toothed wheel is provided for each chain about which the chain is turned around. At least one of these toothed wheels is driven. The toothed wheels in the inlet region 19 and/or in the outlet region may be joined to one another, preferably using a rigid axle. Each transport means usually has a plurality of clamping means that grasp the material web 8 in a clamping manner in the inlet region 19 and transmit the movement of the transport means to the material web 8. The clamping connection between the transport means and the material web 8 is released again in the outlet region of the packaging machine. The packaging trays 6 are molded into the film web 8 in the optional deep-draw station 2, which has an upper tool 3 and a lower tool 4 that has the shape of the packaging tray to be produced. The lower tool 4 is arranged on a lift table 5 that is vertically adjustable, as shown by the double arrow. Prior to each advance of the film, the lower tool 4 is lowered and then raised again. During the further course of the packaging machine, the packaging trays are then filled with the packaging contents 16 in the filling station 7. If no deep-drawing is performed on the lower material web, the packaging contents are placed onto the flat lower material web. An upper film 14 is attached to the material web 8 in a material fit by sealing in the adjacent sealing station 19, which also comprises an upper tool 12 and a vertically adjustable lower tool 28. In the sealing station, as well, the upper tool and/or the lower tool are lowered and raised prior to and after each film transport. Prior to sealing the upper film 14 to the lower film 8, a certain negative pressure, the so-called product vacuum, is present in the filled packaging tray and in the present case is used to draw the upper film 14 towards the packaging tray 8, bonding them over a large surface area. During the further course of the packaging machine, the finished packagings are separated, which in the present case is carried out with the cross cutter 18 and the longitudinal cutter 17. The cross cutter 18 in the present case can also be raised and lowered with a lift device 9.

The sealing tool has a shaping and preferably exchangeable upper tool 12 having an indentation 27 with which the flat film is molded into a dome. To this end, a negative pressure is applied to the upper tool between the tool and the upper film and positions the upper film against the tool 12 and/or draws the upper film into the indentation 27 of the upper tool. Moreover, the upper tool is heated, at least in a segment. As soon as the previously preferably unheated upper film comes into contact with the upper tool, the former is heated to the desired temperature, facilitating its deformation and subsequent sealing to the packaging tray.

The upper film 14 is preferably neither heated nor preformed prior to its entry into the sealing station 15. In addition, the upper film is also preferably not guided in the region of the sealing station or upstream thereof.

FIG. 2a illustrates processes in the sealing station in the inventive method. As soon as the packaging tray 6 and the upper film 14 are disposed in the sealing station, the upper tool 12 and the lower tool 28 are moved together and sealed in their edge region 30a and the upper film and the packaging tray are clamped. Then, as shown by the arrow 13, a negative pressure is applied between the upper tool 12 and the upper film and draws the upper film towards the upper tool via gas through-openings (not shown). The gas through-openings are disposed on the entire surface of the indentation 27, so that the upper film is positioned against the indentation 27 of the upper tool 12, which is shown by the arrows 10. During this, the preferably heated upper tool transfers its heat to the upper film, which has preferably not been heated up to that time, but at most by radiant heat in the sealing station. During or after the forming of the upper film, a negative pressure 24, the so-called product vacuum, is generated between the upper film 14 and the packaging contents 16 and preferably corresponds to the negative pressure above the upper film.

The following refers to FIG. 2b. As soon as the upper film has been sufficiently heated and formed, or after an additional waiting period, the space above the upper film is aerated, i.e., at least the negative pressure that is present is reduced to ambient pressure. FIG. 2b depicts the processes according to the prior art. This is carried out, as depicted by the arrows 10, using gas, in particular ambient air, flowing through the entire upper surface of the indentation at the same time. Because of this, the pressure between indentation 27 and upper film 14 increases, so that the latter is pressed towards the product and the free surface of the packaging tray. The heated upper film 14 encloses the packaging contents in a form fit and bonds in a material fit to the free surface of the packaging tray.

FIGS. 3a and 3b each illustrate an embodiment of the inventive tool. The transport direction of the material webs 8, 14 goes through the plane of the paper. This is also true for all of the following figures. Essentially the statements regarding FIG. 2a may be referenced. As already explained, the indentation has a plurality of gas through-holes 26, for example bores, that are preferably distributed equidistant across the interior of the indentation 27. These gas through-openings may optionally be connected to a negative pressure source (not shown) or to an aeration source (not shown), for example, ambient air. The upper film is drawn by means of the gas through-openings 26 into the indentation until the upper film is positioned thereagainst. At the same time or thereafter, a negative pressure 24, the so-called product vacuum, is generated in the space between the lower material web 8 and the upper film 14. In the illustration according to FIGS. 3a and 3b, a distance is shown between the tools 12 and 28 and the product vacuum is drawn between the two materials 8, 14. The person skilled in the art recognizes that these tools could also be positioned against one another and/or that the product vacuum may also be drawn via a recess in the material web 8. A negative pressure 22 is also preferably generated in the space between the lower material web 8 and the lower tool 28, in particular to prevent the packaging tray from deforming due to the product vacuum.

As already explained in detail in the foregoing, the gas through-opening channels can be divided into at least two groups, in this case exactly two groups, that may be connected independently of one another to a negative pressure and/or aeration source. To this end, the inventive tool has, for example, a chamber 21 in the central region of the indentation or tool and a chamber 23 in the edge region. The pressure in each of the chambers can be adjusted independently of one another. The chamber 21 in the central region is allocated to the gas channels in the central region 32 of the indentation and acts on the indentation with the desired negative pressure and/or aerates it. The same applies to the chambers 23 in the edge region. The chambers 21, 23 can each be connected independently of one another to a negative pressure source 13 and/or an aeration source. Each chamber has a bottom, in this case the inner wall of the indentation, at least one circumferential wall, and a cover. The bottom surface of the chamber in the central region, seen here from above, is preferably square, rectangular, polygonal, oval, or circular. The chamber preferably extends in the edge region in a ring-like manner around the central region.

Two trays and two packaging contents are depicted in the present case. They may be part of one packaging that is subsequently separated. It is also a preferred alternative of the present invention that one indentation is used for producing a plurality of packagings, in the present case two packagings, each with one product. The two packagings are sealed together and then separated from one another downstream.

The example according to FIG. 3b essentially corresponds to the example according to FIG. 3a, so that reference may be made to the statements regarding Example 3a. In the present example, valves 29, 34, 35 are illustrated and may preferably each be controlled individually. These are preferably not on/off valves, but rather valves with which the gas flow may be adjusted. The illustrated valves permit the chambers to be connected selectively to a negative pressure and an aeration source. The valve 35 adjusts the negative vacuum between the material web 8 and the lower tool 28. The person skilled in the art understands that one valve 34 may be sufficient.

FIGS. 4a and 4b show the inventive method, in particular the aeration of the volume 25 between the indentation and the upper film, the so-called upper vacuum. As illustrated using the arrow in FIG. 4a, temporally first the group of the gas through-openings 26 are aerated in the central region 32 of the indentation 27 in that, for example, the valve 29 is connected to the ambient environment. This reduces the negative pressure of the upper vacuum 25, and, as caused by the difference in pressure to the product vacuum 24, the upper film 14 in the central region is arched towards the packaging tray, while the upper film in the edge region of the indentation still remains in contact therewith because the valves 34 are not yet aerated. The upper film preferably forms a balloon shaped will particularly preferably be positioned thereagainst in the central region of the packaging tray. The product vacuum may remain constant or diminish. Temporally offset, for example, in a time and/or pressure controlled manner, the edge region is then also aerated, as is shown by the arrows 20 in FIG. 4b, in that air flows through the valve(s) 34. The valve 29 is preferably closed here. When completely aerated, the entire surface of the upper film is positioned against the product and the surface of the packaging tray facing the upper film. The movement of the upper film towards the packaging tray preferably presses the gas in the product volume out of the packaging towards the edge thereof. The aeration of the central region may begin only relatively slowly and then increase, which may be controlled using the valve 29. The volume flow of aeration gas in particular may be time and/or pressure controlled, wherein the pressure sensor for this is preferably provided in the chamber 21 in the central region. As soon as a certain time window has passed since the beginning of the aeration of the central region and/or as soon as the negative pressure has been reduced by a certain measure toward ambient pressure, the aeration through the edge region of the bores 26 is initiated. This aeration then preferably occurs as rapidly as possible, particularly preferred with a completely open valve 34. The valve 29 is preferably closed during aeration through the bores in the edge region.

In the illustration according to FIG. 5, the lower tool was raised, as depicted by the arrow 31, in order to close the gap between the upper tool 12 and the lower tool 28. This may be done, for example, in order to apply a sealing seam, for example in the edge region. The person skilled in the art understands that this gap may already be sealed from the beginning, i.e., also in the examples according to FIGS. 3a, 3b, 4a, and 4b.

FIG. 6 shows the chambers in a top view. The chamber 21, which in the present case has a rectangular footprint, is clearly visible in the central region 32. The chamber for the group of gas through-openings 26 in the edge region 33 extends in a ring shape about the chamber of the central region. The person skilled in the art understands that other footprint shapes are also possible.

In the preferred embodiment according to FIG. 7, a bypass 36 is provided between the two chambers and permits the entire volume of the indentation to be evacuated by connecting the chamber of the central region to a vacuum source. Provided in the frame between the chambers 21, 23 in the center tool is at least one opening that is closed with a membrane in a valve-like manner. The bypass opens using a movement of the membrane, as soon as the drawing by the vacuum begins, and/or the negative pressure in the chamber 21 of the central region has reached a threshold value.

REFERENCE LIST

• • 1 Packaging machine
  • 2 Forming station, deep-drawing station
  • 3 Upper tool of the deep-drawing station
  • 4 Lower tool of the deep-drawing station
  • 5 Lift table, carrier of a tool of the sealing station, deep-drawing station, and/or cutting device
  • 6 Packaging tray
  • 7 Filling station
  • 8 Material web, lower material web, lower film web
  • 9 Lift device
  • 10 Forming, stretching of the upper film, application to the product and packaging tray
  • 11 Lower sealing tool of the sealing station
  • 12 Upper tool of the sealing station, sealing tool
  • 13 Negative pressure source
  • 14 Upper film web, skin film
  • 15 Sealing station
  • 16 Packaging contents
  • 17 Longitudinal cutter
  • 18 Cross cutter
  • 19 Inlet region
  • 20 Aeration and/or positive pressure source
  • 21 Chamber in the central region
  • 22 Lower vacuum
  • 23 Chamber in the edge region
  • 24 Product vacuum
  • 25 Upper vacuum
  • 26 Gas through-opening, recess, bore
  • 27 Indentation
  • 28 Lower tool
  • 29 Valve for the chamber of the central region
  • 30 Enclosing housing/clamping tool of the sealing station
  • 30a Edge region/clamping region of the surrounding housing
  • 31 Lift of the lower tool
  • 32 Central region, partial region
  • 33 Edge region
  • 34 Valve for the chamber of the edge region
  • 35 Valve for the lower vacuum
  • 36 Bypass