DEVICE FOR SUPPLYING A GAS STREAM TO A TOOL FOR MOLDING MOLDED PARTS, TOOL WITH SUCH A DEVICE, AND METHOD FOR CONTROLLING THE SUPPLY OF A GAS STREAM

A device for supplying a gas stream to a tool for molding molded parts made of a fiber-containing material. Steam generated during molding is removed from the molded parts pressed in the tool via channels in the tool. A tool with such a device and a method for controlling the supply of a gas stream into the tool are described.

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Description
PRIORITY CLAIM

The present application claims priority under 35 U.S.C. § 119 to German Patent Application No. DE 10 2023 126 173.8, filed Sep. 26, 2023, the disclosure of which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

A device for supplying a gas stream to a tool for molding molded parts made of a fiber-containing material, where steam generated during molding is removed from the molded parts pressed in the tool via channels in the tool, a tool with such a device and a method for controlling the supply of a gas stream into a tool are described.

Fiber-containing materials are increasingly used, for example, to produce packaging for food (e.g., trays, capsules, boxes, etc.) and consumer goods (e.g., electronic devices, etc.) as well as beverage containers. Everyday items, such as disposable cutlery and tableware, are also made from fiber-containing material. Fiber-containing materials contain natural fibers or artificial fibers. Recently, fiber-containing material is increasingly used that has or is made of natural fibers that can be obtained, for example, from renewable raw materials or waste paper. The natural fibers are mixed in a so-called pulp with water and optionally further additives, such as starch. Additives can also have an effect on color, barrier properties and mechanical properties. This pulp can have a proportion of natural fibers of, for example, 0.1 to 10 wt. %. The proportion of natural fibers varies depending on the method used for the production of packaging etc. and the product properties of the product to be produced.

BACKGROUND

The production of fiber-containing products from a pulp generally takes place in a plurality of work steps. For this purpose, a fiber processing device has a plurality of stations or forming stations. In a forming station, for example, fibers can be suctioned in a cavity of a suction tool, thus forming a preform. For this purpose, the pulp is provided in a pulp supply, and the suction tool is at least partially immersed in the pulp with at least one suction cavity whose geometry essentially corresponds to the product to be manufactured. During the immersion, suction takes place via openings in the suction cavity, which are connected to a corresponding suction device, where fibers from the pulp accumulate on the surface of the suction cavity. The suctioned fibers or a preform can subsequently be brought into a pre-pressing tool via the suction tool, and the preform is pre-pressed. For this purpose, for example, it is possible to use elastic mold bodies that are inflated in order to press and, in the process, exert pressure on the preforms. During this pre-pressing process, the fibers in the preform are compressed and the water content of the preform is reduced. Alternatively, preforms can be provided by means of scooping, where a scoop tool is immersed in the pulp and during startup fibers are deposited on molded parts of the scoop tool.

After this, preforms are pressed in a hot-pressing device to form finished molded parts. In this process, preforms are inserted into a hot press tool that has, for example, a lower tool half and an upper tool half that are heated. In the hot-pressing tool, the preforms are pressed between molding devices in cavities under heat input, with residual moisture being removed by the pressure and heat so that the moisture content of the preforms is reduced from about 60 wt. % before hot pressing to, for example, 5-10 wt. % after hot pressing. The steam produced during hot pressing is suctioned off during the hot pressing via openings in the cavities and channels in the hot press tool.

A production method and a fiber processing device are known, for example, from DE 10 2019 127 562 A1.

To remove hot steam, it has already been proposed to provide an additional gas stream that is introduced into the hot-pressing tool and mixes with the steam extracted from the cavities in the hot-pressing tool. However, an unregulated flow of an additional gas stream causes an asymmetric cooling of the hot-pressing tool and the associated molding devices. The asymmetric cooling has a decisive effect on the molding step of hot pressing since it also severely impairs the heating of the molding devices. As a result, the cycle time increases because the heating time for the cavities that take the longest to get back to the required temperature determines the time.

SUMMARY Object

In contrast, it is an object to present a solution that provides a uniform temperature distribution in a ventilated tool. A further object is to solve the problems of the prior art and to provide an alternative to known tools.

Solution

The above-mentioned object is achieved by a device for supplying a gas stream to a tool for molding molded parts made of a fiber-containing material, where steam generated during molding is removed from the molded parts pressed in the tool via channels in the tool, the tool including first channels in a tool body of the tool in regions of molding devices for molding molded parts and at least one second channel that is connected to the first channels and surrounds the regions in the tool body with the first channels, where the diameter of the at least one second channel is larger than the diameter of the first channels.

The device achieves a targeted directing and subdivision of the guided gas flow or steam, where a main gas flow and side gas flows or main and side steam flows are generated in and around the tool. The first channels run in a tool body and are connected to the molding devices located above or below via openings and optionally further channels. The first channels extend within the tool body parallel to the molding surface on which molding devices are arranged or provided. Here, such a tool body has regions that are located below or above the molding devices and are assigned to them. When steam is extracted during a hot-pressing process, the steam reaches these regions first. When an additional gas stream is supplied for ventilation, the ventilation takes place in accordance with the position of the supply point and the design of the first channels as well as the number and size of the molding device and the shape of the tool body. Since the supply is usually carried out at one side/point in the prior art, there is an uneven supply, so that the steam in the tool body is discharged to different degrees in the first channels, where some regions are ventilated quickly and therefore tend to cool down rapidly, while in other regions, the hot steam “stands” or lingers for a relatively long time so that no cooling occurs. By means of at least one second channel, which preferably surrounds the tool or the tool body in the plane of the first channels or parallel thereto, the additionally supplied gas stream can, for example, be introduced on two or three sides of a tool block, so that the ventilation is more uniform as a result of this alone. If the residence time of steam discharged from the cavities or molding devices as well as the flow rate are determined in advance, the supply of a gas flow from the second channel into individual channels can also be controlled in a targeted manner so that the overall flow rate is optimized with regard to a uniform temperature distribution.

Advantageously, the at least one second channel is designed such that it has a larger cross section than the first channels, whereby a flow through the first channels by a gas stream supplied through the at least one second channel is regulated in a first step.

By adapting and selecting flow cross sections and narrowing or widening them, the device enables the main/side gas flows or steam flows to be subdivided. Gas flows are understood to be both gas mixtures (e.g., air) and gases.

The subdivision of the channels in the tool and the device also means that the steam generated, including the thermal energy stored therein, can remain specifically in points without a significant increase in pressure and the reduced flow at these points reduces an unnecessary energy dissipation.

Here, it is particularly important that the steam can escape from the molding devices or cavities into the periphery (tool body, base, basic structure, pipe system, hose system) without pressure, or almost without pressure, where the steam stream is superimposed on an existing air or gas stream.

This achieves a uniform temperature distribution in a tool, e.g., a hot-pressing tool for the production of molded parts made of a fiber-containing material. This can yield an increase of the efficiency of a hot-pressing process, an increase of the process stability, and an improvement of the product quality of the hot-pressed molded parts. Furthermore, when designing the cross sections for the first channels and the at least one second channel, the local cooling of molding devices and/or a tool body of the tool can be taken into account, which occurs during the evaporation of escaping water from preforms due to the thermal energy extracted from the tool or the molding devices so that, for example, a tool body in particular can also be kept substantially at a constant temperature during the hot pressing process, in particular over a plurality of cycles. This has a further positive effect on the above advantages.

In further embodiments, the first channels may be interconnected at least in the regions of molding devices so that the ventilation or flow for targeted steam removal is improved.

In further embodiments, the at least one second channel can surround all regions of molding devices of a tool body together. Preferably, the at least one second channel extends around a tool body and therefore surrounds it on four sides in the case of a rectangular tool body. The at least one second channel serves not only as a channel for the joint supply of an additional gas flow but also for the removal of a saturated gas stream, where the saturated gas stream has absorbed steam from the regions of the molding devices.

In further embodiments, connection points between the first channels and the at least one second channel can have a smaller diameter than the first channels. Here, the connection points act as throttle elements and significantly influence the amount of gas stream flowing into the respective first channel. The connection points can be designed differently for the first channels in order to achieve the flow required to achieve a uniform temperature distribution.

In further embodiments, the opening width of connecting points between the first channels and the at least one second channel may be adjustable, for example in order to be able to make an adjustment during a tool change for the production of other molded parts, where the molding devices connected to a tool body are exchanged. During such a tool change, the regions of molding devices may change. In addition, other molding device-specific characteristics influence the amount of steam that enters the first channels. This means that the ability to adapt and change the opening width can be used to take into account a tool change and also to make an adjustment while operating the tool if, for example, changes are detected in the finished molded parts and/or in the discharged saturated gas stream. For this purpose, for example, a change can be detected via a controller and corresponding detection devices (camera, sensors, etc.). As a result, the controller can, for example, control throttle valves to change the opening width accordingly. For this purpose, for example, a camera can record the surface of the molded parts after hot pressing. This allows moist regions to be detected visually. The position of the respective molded part can be used to directly draw a conclusion about the associated first channels or the respective region of the molding device, and the corresponding throttle valves of these channels can be controlled. Machine learning can also be integrated, where, for example, a test run is carried out and reference data is obtained for the controller.

In further embodiments, the at least one second channel can be subdivided into channel sections, and the supply of a gas stream into the channel sections may be adjustable. This also allows the amount of gas stream primarily available and supplied to the first channels to be further controlled in order to achieve a uniform temperature distribution in the tool.

In further embodiments, the supply of a gas stream into the at least one second channel and/or the first channels may be adjustable by throttle elements and/or conveying devices. Throttle elements can be, for example, valves or throttle valves. Conveying devices can be, for example, pumps or fans that are integrated into and/or connected to the second channel. In further embodiments, the flow through the tool and the supply of an additional gas stream can also be controlled via a suction or negative pressure prevailing in a discharge line for saturated gas stream. Conveying devices, for example, can be used for this purpose.

In further embodiments, the device may have at least one device for controlling the temperature of a gas stream that can be supplied into the at least one second channel and/or the first channels in order to influence the temperature of the supplied gas stream. For example, heating can take place because warmer air can experience a higher saturation of water, which means more steam can be removed.

In further embodiments, the first channels may have a number of channels extending orthogonally to one another. Ideally, the at least one second channel has large cross sections around the tool and cross-sectional constrictions in transverse and longitudinal channels (first channels) in a tool body.

Such a device can, for example, be attached to a tool with already existing first channels for flow through or be provided as an integral component of a tool.

The above-mentioned object is also achieved by a tool for molding molded parts made of a fiber-containing material, where steam generated during molding can be removed from the molded parts pressed in the tool via channels in the tool, the tool including first channels in a tool body of the tool in the region of molding devices for molding molded parts and at least one device according to one of the above embodiments, where the at least one device has at least one second channel that is connected to the first channels and surrounds the regions in the tool body with the first channels.

A main gas stream integrated in the tool is directed in and around the tool by a targeted arrangement of channels and their cross sections in such a way that a flowing through, cold or preheated, preferably dry, draft gas stream does not cool a hot tool body asymmetrically despite uniform ventilation and therefore creates a uniform temperature pattern on the cavities or molding devices.

The above-mentioned object is further achieved by a method for controlling the supply of a gas stream into a tool for molding molded parts made of a fiber-containing material, where steam generated during molding is removed from the molded parts pressed in the tool via channels in the tool, where the tool has first channels in a tool body of the tool in the region of molding devices for molding molded parts and at least one device according to one of the above embodiments is provided, where the at least one device has at least one second channel that is connected to the first channels and surrounds the regions in the tool body with the first channels, where the supply of a gas stream into the at least one second channel and/or the first channels can be controlled via at least one throttle device and/or a conveying device.

In so doing, the supplied gas/air stream or steam flow is directed into technically advantageous paths since main and side channels are provided in the tool body of the tool onto which the resulting steam can “jump” without pressure and according to the amount produced.

In addition to the main channels, the steam flow is specifically influenced and directed by side channels with cross-sectional constrictions and widenings (bore diameters, blind plugs, etc.) so that steam accumulation zones can also form symmetrically in the tool. In these zones, the resulting energy “lingers” statistically longer or deliberately shorter in order to achieve the same temperature pattern or uniform temperature distribution.

The solution proposed herein enables the conversion of asymmetric cooling from the prior art to a symmetrical influence by targeted directing of the steam/draft gas stream/flow.

Further features, embodiments and advantages result from the following illustration of exemplary embodiments with reference to the figures.

BRIEF DESCRIPTION OF THE FIGURES

In the drawings:

FIG. 1 depicts a schematic representation of a fiber processing device, according to some embodiments.

FIG. 2 depicts a schematic perspective representation of the tool bodies of a hot pressing device, according to some embodiments.

FIG. 3 depicts a schematic plan view of one of the tool bodies of FIG. 2, according to some embodiments.

FIG. 4 depicts a schematic representation of a tool body with a device for supplying a gas stream according to some embodiments.

FIG. 5 depicts a schematic representation of the temperature distribution in a tool body, according to some embodiments.

FIG. 6 depicts a schematic representation of a tool body, according to some embodiments.

 DETAILED DESCRIPTION

Various embodiments of the technical teaching described herein are shown below with reference to the figures. Identical reference signs are used in the figure description for identical components, parts and processes. Components, parts and processes that are not essential to the technical teachings disclosed herein or that are obvious to a person skilled in the art are not explicitly reproduced. Features specified in the singular also include the plural unless explicitly stated otherwise. This applies in particular to statements such as “a” or “one”. Furthermore, terms “stream” and “flow” are used as synonyms in the entire description.

FIG. 1 depicts a schematic representation of a fiber processing device 1000 for producing three-dimensional molded parts 3000 made of a fiber-containing material. In the shown exemplary embodiment, the fiber-containing material for the production of molded parts 3000 is processed in a pulp tank 200 of the fiber processing device 1000. For this purpose, for example, water and fibrous materials and, if necessary, additives can be introduced into a pulp tank 200 via a liquid supply, and the pulp can be treated in the pulp tank 200 by mixing the individual components under heat input and by auxiliary means, such as an agitator.

Pulp refers to an aqueous solution containing fibers, where the fiber content of the aqueous solution can be in a range of 0.1 to 10 wt. %. In addition, additives such as starch, chemical additives, wax, etc. can be contained. The fibers can be, for example, natural fibers, such as cellulose fibers, or fibers from a fiber-containing original material (for example waste paper). A fiber treatment plant offers the possibility of preparing pulp in a large quantity and providing a plurality of fiber processing devices 1000.

The fiber processing device 1000 can be used to produce, for example, biodegradable molded parts 3000 such as cups, capsules, bowls, plates, and other molded and/or packaging parts (e.g., as holder/supporting structures for electronic appliances). Since a fibrous pulp with natural fibers is used as the starting material for the products, the products manufactured in this way can themselves be used as a starting material for the manufacture of such products after their use, or they can be composted, because they can usually be completely decomposed and do not contain any substances that are harmful to the environment.

The fiber processing device 1000 shown in FIG. 1 has a frame 100 that can be surrounded by a cladding. The supply units 300 of the fiber processing device 1000 include, for example, interfaces for the supply of media (e.g., water, pulp, compressed air, gas, etc.) and energy (power supply), a central control unit 310, at least one suction device 320 (e.g., including a vacuum tank and/or ventilator), line systems for the various media, pumps, valves, lines, sensors, measuring devices, a bus system, etc., and interfaces for bidirectional communication via a wired and/or wireless data connection. Instead of a wired data connection, there can also be a data connection via a fiber optic line. The data connection can be, for example, between the control unit 310 and a central controller for a plurality of fiber processing devices 1000, to a fiber preparation plant, to a service point, and/or further devices. It is also possible to control the fiber processing device 1000 via a bidirectional data connection via a mobile device, such as a smartphone, tablet computer, or the like.

The control unit 310 is in bidirectional communication with an HMI panel 700 via a bus system or a data connection. The HMI (human-machine interface) panel 700 has a display that displays operating data and states of the fiber processing device 1000 for selectable components or the entire fiber processing device 1000. The display can be designed as a touch display so that adjustments can be made manually by an operator of the fiber processing device 1000. Additionally or alternatively, further input means, such as a keyboard, a joystick, a keypad, etc. for operator inputs, can be provided on the HMI panel 700. In this way, settings can be changed and the operation of the fiber processing device 1000 can be influenced.

The fiber processing device 1000 has a robot 500. The robot 500 is designed as a so-called 6-axis robot and is thus able to pick up parts within its radius of action, to rotate them and to move them in all spatial directions. Instead of the robot 500 shown in the figures, other handling devices can also be provided that are designed to pick up and twist or rotate products (preforms, molded parts) and move them in the various spatial directions. In addition, such a handling device may also be otherwise configured, in which case the arrangement of the corresponding stations of the fiber processing device 1000 may differ from the exemplary embodiment shown.

A suction tool 520 is arranged on the robot 500. In the exemplary embodiment shown, the suction tool 520 has cavities as suction cavities that are formed as negatives of the three-dimensional molded parts 3000 to be molded. The cavities can have, for example, a net-like surface on which fibers from the pulp are deposited during the suction. Behind the net-like surfaces, the cavities are connected to a suctioning device via channels in the suction tool 520. The suctioning device can be realized, for example, by a suction device 320. Pulp can be suctioned in via the suctioning device when the suction tool 520 is located within the pulp tank 200 in such a way that the cavities are at least partially located in the aqueous fiber solution—the pulp. A vacuum or a negative pressure for suctioning fibers, when the suction tool 520 is located in the pulp tank 200 and the pulp, can be provided via the suction device 320. For this purpose, the fiber processing device 1000 has corresponding means at the supply units 300. The suction tool 520 has lines for providing the vacuum/negative pressure from the suction device 320 in the supply units 300 to the suction tool 520 and the openings in the cavities. Valves are arranged in the lines, which can be controlled via the control unit 310 and thus regulate the suction of the fibers. It is also possible for the suction device 320 to perform a “blow-out” instead of a suction, for which purpose the suction device 320 is switched to another operating mode in accordance with its design.

During the production of molded parts 3000 made of a fiber material, the suction tool 520 is immersed in the pulp, and a negative pressure/vacuum is applied to the openings of the cavities, so that fibers are suctioned out of the pulp and are deposited for example on the mesh of the cavities of the suction tool 520.

Thereafter, the robot 500 lifts the suction tool 520 out of the pulp tank 200 and moves it together with the fibers adhering to the cavities, which still have a relatively high moisture content of, for example, over 80 wt % of water, to a pre-pressing station 400 of the fiber-processing device 1000, where the negative pressure is maintained in the cavities for the transfer. The pre-pressing station 400 has a pre-pressing tool with pre-pressing molds. The pre-pressing molds can, for example, be designed as positives of the molded parts 3000 to be manufactured and have a corresponding size with regard to the shape of the molded parts 3000 for receiving the fibers adhering in the cavities.

During the production of molded parts 3000, the suction tool 520 is moved, together with the fibers adhering in the cavities, to the pre-pressing station 400 in such a way that the fibers are pressed into the cavities. The fibers are pressed together in the cavities, so that a stronger connection is thereby produced between the fibers. In addition, the moisture content of the preforms formed from the suctioned-in fibers is reduced, so that the preforms formed after the pre-pressing only have a moisture content of, for example, 60 wt. %. To squeeze out water, flexible pre-pressing molds can be used, which are inflated, for example, by means of compressed air (process air), thereby pressing the fibers against the wall of a cavity of a further suction tool part. As a result of the “inflation,” both water is squeezed out, and the thickness of the sucked-in fiber layer is reduced.

During pre-pressing, liquid or pulp can be extracted and returned via the suction tool 520 and/or via further openings in pre-pressing molds or pre-pressing tool parts (cavities).

After pre-pressing in the pre-pressing station 400, the preforms produced in this way are moved to a hot-pressing station 600 on the suction tool 520 via the robot 500. For this purpose, the negative pressure is maintained at the suction tool 520 so that the preforms remain in the cavities. The preforms are transferred via the suction tool 520 to a lower tool body 620 that can be moved along the production line out of the hot-pressing device 610. If the lower tool body 620 is in its extended position, the suction tool 520 is moved to the lower tool body 620 in such a way that the preforms can be placed on molding devices 624 of the lower tool body 620. Subsequently, an overpressure is generated via the openings in the suction tool 520 so that the preforms are actively deposited by the cavities, or the suction is ended so that the preforms remain on the molding devices 624 of the lower tool body 620 due to gravity. By providing overpressure at the openings of the cavities, pre-pressed preforms that rest/adhere in the cavities can be released and dispensed.

Thereafter, the suction tool 520 is moved away via the robot 500 and the suction tool 520 is immersed into the pulp tank 200 in order to suction further fibers for the production of molded parts 3000 from fiber-containing material.

After the transfer of the preforms, the lower tool body 620 moves into the hot-pressing station 600. In the hot-pressing station 600, the preforms are pressed under heat input and high pressure so as to produce finished molded parts 3000, for which purpose an upper tool body 630 is brought onto the lower tool body 620 via a press. The upper tool body 630 has cavities (molding devices) corresponding to the molding devices 624. The molding devices 624 can be connected (e.g., screwed) to the tool bodies 620, 630 or can be integrally installed. In the exemplary embodiments shown, the molding devices 624 are screwed to the tool bodies 620, 630.

After the hot pressing process, the lower tool body 620 and the upper tool body 630 are moved away from one another, and the upper tool body 630 is moved along the fiber processing device 1000 in the manufacturing direction, where, after hot pressing, the manufactured molded parts 3000 are suctioned in via the upper tool body 630 and therefore remain within the cavities. Thus, the manufactured molded parts 3000 are removed from the hot-pressing station 600 and, via the upper tool body 630, are deposited after traveling on a conveyor belt of a conveying device 800. After depositing, the suction via the upper tool body 630 is ended and the molded parts 3000 remain on the conveyor belt. The upper tool body 630 moves back into the hot-pressing station 600, and a further hot-pressing process can be carried out. Alternatively, the lower tool body 620 may be moved in an opposite direction prior to being extended to receive the preforms in order to move the manufactured products/molded parts 3000 out of the hot-pressing device for further transport. Furthermore, a hot-pressing device 610 can also be equipped with preforms in other ways, where no lateral movement of tool bodies 620, 630 is necessary.

In the exemplary embodiment, the fiber processing device 1000 further has a conveying device 800 with a conveyor belt. The manufactured molded parts 3000 made of fiber-containing material can be placed on the conveyor belt after final molding and hot pressing in the hot-pressing station 600 and can be removed from the fiber processing device 1000. In further embodiments, after the molded parts 3000 have been deposited on the conveyor belt of the conveying device 800, further processing may take place, such as filling and/or stacking of the manufactured products. The stacking can take place, for example, via an additional robot or another device.

The fiber processing device 1000 from FIG. 1 shows a possible embodiment. A fiber processing device according to the technical teaching described herein can also have only one forming station with an exchangeable tool, e.g., a suction tool 520 or a hot-pressing tool, in which fiber-containing material can be processed, where different tools for producing different three-dimensional molded parts 3000 can be accommodated in the at least one forming station. The further stations and devices shown for the fiber processing device 1000 of FIG. 1 are not absolutely necessary for implementing the technical teaching.

The tool bodies 620, 630 are heated by heating elements and therefore brought to the required temperature. During hot pressing, the water contained in the relatively moist preforms evaporates. This hot steam is discharged through openings and channels in the molding devices 624. For this purpose, the tool bodies 620, 630 have corresponding channels that are connected to the openings. Further, the tool bodies 620, 630 have side channels 622 (first channels) that extend through the tool bodies 620, 630 and are connected to the openings and channels in the molding devices 624. A first group of parallel running side channels 622 runs orthogonally to a second group of parallel running side channels 622, where the side channels 622 of the first group and the second group intersect and are connected to one another at the interfaces.

FIG. 2 depicts a schematic perspective representation of tool bodies 620, 630 of a hot-pressing device 610. The hot-pressing station 610 has four molding devices 624 and corresponding cavities on the opposite tool bodies 620, 630. In FIG. 2, molded parts 3000 are placed on the four molding devices 624.

FIG. 3 depicts a schematic plan view of the lower tool body 620 of FIG. 2, where the molding device 624 is shown in the lower right region without a molded part 3000.

In a hot-pressing device 610, the steam escaping from the hot surfaces of the moist preforms during the hot-pressing process is suctioned off. To support the transport of steam, a gas stream, e.g. process air, is introduced into the side channels, which is preferably heated (via additional heating devices or heat exchangers).

In order to achieve a uniform temperature distribution in the tool body 620, a device 640 is provided that has a main channel 642 (second channel) that surrounds the tool body 620. The main channel 642 has a larger diameter than the side channels 622. For example, the ratio of the diameter of the main channel 642 to the diameter of the side channels 622 can be 1:0.1-0.8.

FIG. 4 depicts a schematic representation of a tool body 620 with a device 640 for supplying a gas stream. The main channel 642 has four channel sections 660, 662, 664, 666. The flow of the process air stream introduced via the main channel 642 is determined such that an optimal flow is achieved in order to achieve an optimal, uniform temperature distribution. In FIG. 5, for example, a temperature distribution in the tool body 620 is shown, where the temperature is highest in particular in regions 650 and, above all, substantially the same in all four regions 650 and therefore also in the molding devices 624. As shown in FIG. 4, the steam in the regions 650 exits in all directions and is distributed in the regions 650 that are the channel sections of the side channels associated with the molding devices 624.

Due to the design of the main channel 642, process air can be both supplied and discharged in the four channel sections 660, 662, 664, 666, as shown schematically in FIG. 4. In the exemplary embodiment, the steam-air mixture (saturated gas stream) is discharged via the channel section 666 of the main channel 642 and supplied to a further treatment (e.g., heat exchanger).

For this purpose, it is necessary to introduce the process air not only into one side channel 622 but into a plurality of side channels 622 or all side channels. In addition, the amount of process air for each side channel 622 must be determined, where the amount for each side channel 622 may vary.

With the temperature distribution shown in FIG. 5, steam, for example, can linger longer in the regions 650 than in the sections surrounding the regions 650. In addition, the process air guidance in the tool body 620 is adjusted in such a way that excessive cooling is prevented.

The cross sections in the connecting points between the main channel 642 and the side channels 622 are designed such that the temperature distribution shown in FIG. 5 is established. For this purpose, controllable throttle elements (flaps, valves) can also be provided in the connection points. This allows an adjustment to be made during operation and/or a change to be made during a tool change.

By selecting and arranging cross sections in the channels (main channel 642, side channels 622), the flow conditions can be specifically directed to ensure uniform temperature distribution.

This achieves a uniform temperature distribution in the tool body 620, whereby an increase in the efficiency of the hot-pressing process, an increase in the process stability as well as the product quality is achieved.

LIST OF REFERENCE SIGNS

    • 100 Frame
    • 200 Pulp tank
    • 300 Supply units
    • 310 Control unit
    • 320 Suction device
    • 400 Pre-pressing station
    • 500 Robot
    • 520 Suction tool
    • 600 Hot pressing station
    • 610 Hot pressing device
    • 620 Lower tool body
    • 622 side channel
    • 624 Molding device
    • 630 Upper tool body
    • 640 Device
    • 642 Main channel
    • 650 Region
    • 660 Canal section
    • 662 Canal section
    • 664 Canal section
    • 666 Canal section
    • 700 HMI panel
    • 800 Conveying device
    • 810 Camera
    • 1000 Fiber processing device
    • 3000 Molded part

Claims

1. A device for supplying a gas stream to a tool for molding molded parts made of a fiber-containing material, wherein steam generated during molding is removed from the molded parts pressed in the tool via channels in the tool, the tool comprising first channels in a tool body of the tool in regions of molding devices for molding the molded parts and at least one second channel that is connected to the first channels and surrounds the regions in the tool body with the first channels, wherein a diameter of the at least one second channel is larger than a diameter of the first channels.

2. The device according to claim 1, wherein the first channels are interconnected at least in the regions of molding devices.

3. The device according to claim 1, wherein the at least one second channel jointly surrounds all the regions of the molding devices of the tool body.

4. The device according to claim 1, wherein connection points between the first channels and the at least one second channel have a smaller diameter than the first channels.

5. The device according to claim 1, wherein an opening width of connection points between the first channels and the at least one second channel is adjustable.

6. The device according to claim 1, wherein the at least one second channel is subdivided into channel sections, and the supply of a gas stream into the channel sections is adjustable.

7. The device according to claim 1, wherein the supply of a gas stream into the at least one second channel and/or the first channels is adjusted by throttle elements and/or conveying devices.

8. The device according to claim 1, further comprising at least one device for controlling a temperature of a gas stream that is fed into the at least one second channel and/or the first channels.

9. The device according to claim 1, wherein the first channels comprise a number of channels running orthogonally to one another.

10. A tool for molding molded parts made of a fiber-containing material, wherein steam generated during molding is removed from the molded parts pressed in the tool via channels in the tool, the tool comprising first channels in a tool body of the tool in regions of molding devices for molding the molded parts and at least one device having at least one second channel that is connected to the first channels and surrounds the regions in the tool body with the first channels.

11. A method for controlling a supply of a gas stream into a tool for molding molded parts made of a fiber-containing material, wherein steam generated during molding is removed from the molded parts pressed in the tool via channels in the tool, wherein the tool has first channels in a tool body of the tool in regions of molding devices for molding molded parts, and at least one device having at least one second channel that is connected to the first channels and surrounds the regions in the tool body with the first channels, wherein the supply of a gas stream into the at least one second channel and/or the first channels is controlled via at least one throttle device and/or a conveying device.

Patent History
Publication number: 20250101686
Type: Application
Filed: Sep 18, 2024
Publication Date: Mar 27, 2025
Inventors: Thomas Auer (Saaldorf-Surheim), Hubert Rehrl (Teisendorf), Josef Rehrl (Teisendorf), Heinz Neuhofer (Freilassing), Raphael Köppl (Bischofswiesen)
Application Number: 18/888,481
Classifications
International Classification: D21J 3/00 (20060101);