Apparatus and method for dry manufacturing rigid cellulose products

Abstract

The present invention relates to a method and an apparatus for dry manufacturing rigid cellulose product (2) having essentially non-flat general shape from a cellulose blank (10). The apparatus (1) comprises a conveyor arrangement (20) comprising an endless conveyor belt (21) configured for continuously moving at a predetermined traveling speed, a product forming unit (11) that comprises a moulding tool having a first mould part (15) and a second mould part (16) displaceable in an axial direction in relation to each other in order to press the cellulose blank (10) therebetween, wherein the cellulose blank (10) comprises a product area (25). The apparatus further comprises an in-feed device (22) that comprises a suction device (24) configured to engage and transfer the cellulose blank (10) from the continuously moving conveyor belt (21) into the open moulding tool, the suction device (24) having a perforated area corresponding in size to at least the product area of the cellulose blank (10), and wherein the suction device (24) in the transport direction of the conveyor arrangement (20) during engagement with the cellulose blank (10), is configured to move in conformity with the traveling speed of the conveyor belt (21).

Description

Technical field of the Invention

[0001] The present invention relates in general to the field of method and apparatus for dry manufacturing of rigid cellulose products having essentially non-flat general shape from cellulose blank. Such cellulose products may be used for packaging, storing, transporting and / or displaying other products such as electronics, tools, jewelry, food, dairy products, cosmetics, etc., and / or may be used as single / multiple use disposable articles. The method and apparatus are especially defined to secure reliable feeding of discrete cellulose blanks from a continuous flow of discrete cellulose blanks into a cyclically operated moulding tool. By cellulose products means products that mainly consists of the cellulose part of organic matter.

[0002] The present invention relates specifically to an apparatus and a method for dry manufacturing rigid cellulose products, wherein the apparatus comprises a conveyor arrangement comprising an endless conveyor belt for receiving the cellulose blank, wherein the conveyor belt is configured for continuously moving at a predetermined traveling speed in a transport direction of the conveyor arrangement, and a product forming unit that comprises a moulding tool having a first mould part and a second mould part, wherein at least one of the first mould part and the second mould part is displaceable in an axial direction in relation to the other in order to press the cellulose blank therebetween into final shape, wherein the cellulose blank comprises a product area. The method comprises the general steps of providing the cellulose blank onto the endless conveyor belt of the conveyor arrangement, wherein the conveyor belt is continuously moving and has a predetermined traveling speed in the transport direction of the conveyor arrangement, transferring the cellulose blank from the conveyor arrangement into the open moulding tool, and forming rigid cellulose product having essentially non-flat general shape from the cellulose blank in the moulding tool by applying a predetermined pressure P in the axial direction of the moulding tool.Background of the Invention

[0003] There are many situations where it is desirable to provide two-dimensional (2D) or three-dimensional (3D) shaped objects made of sustainable materials, such as biomaterials, instead of using plastic / polymer materials. A biomaterial commonly used for packaging and disposable articles is wet moulded pulp based on cellulose fibres. Such wet moulded pulp has the advantage of being considered as a sustainable material, since it is produced from biomaterials and can be recycled after use. Wet moulded pulp comprises more or less only water and separated cellulose fibers, and consequently, wet moulded pulp has been popular to use for primary packaging applications (packaging next to the article), for secondary packaging applications (assembly of such primary packages), as well as for manufacturing of disposable articles / products.

[0004] However, a common disadvantage with all wet-forming techniques is the need for large amounts of water during the preparations of the cellulose pulp and the need for drying during the manufacturing / moulding of the cellulose product, which is a time and energy consuming step leading to low production speed and substantial high investment cost in machines and tooling. Meaning that the wet-forming techniques are not feasible to replace fossil-based alternatives neither in small nor large scale production of rigid cellulose products. Thereto, the aesthetical and mechanical properties of a wet-moulded cellulose product are hard to control with desirable precision, due to un-uniform cellulose pulp and due to the wet moulding manufacturing technique per se.

[0005] Therefore many actors / companies, starting a few decades ago, have changed their focus and investments towards dry-forming techniques wherein rigid cellulose products are manufactured from separated cellulose fibres that are introduced into a product forming unit in the shape of a cellulose blank / web, wherein the cellulose blank is formed / moulded into the shape of the intended cellulose product and wherein the cellulose fibres are bonded to each other using heat and pressure. The dry-forming techniques comprises different steps of generating an air-laid cellulose blank, that is fed into a product forming unit, i.e. thermo-forming press.

[0006] Some manufacturing techniques uses a continuous cellulose blank that is intermittently fed into the cyclically operated moulding tool. There are known processes wherein the continuous cellulose blank is continuously formed / provided onto a conveyor belt, wherein the continuous cellulose blank has to be buffered in a buffering zone between subsequent press cycles. One obvious drawback of having a continuous cellulose blank is the generation of very much scrap material, which scrap material has to be fed back into the process. Another drawback of having a continuous cellulose blank that is buffered before the cyclic moulding tool, is that the continuous cellulose blank has to be rapidly accelerated / pulled from the buffering zone into the moulding tool in order to obtain an applicable production rate. Forces arising due to the rapid acceleration, risk to pull apart the continuous cellulose blank, which is a fluffy structure of a bulk of short / small cellulose fibres that are loosely connected to each other. According to other known processes, the continuous cellulose blank is intermittently formed / provided onto the conveyor belt, i.e. each segment of the continuous cellulose blank is formed during one press cycle. However, rapid acceleration of the continuous cellulose blank from standstill and into the moulding tool is still needed and the interface between each segment of the continuous cellulose blank is even weaker than the continuously formed / provided cellulose blank.

[0007] The applicant utilizes a continuous stream of discrete cellulose blanks that are formed / provided onto a continuously moving conveyor belt, wherein the cellulose blanks are fed into the moulding tool batchwise, i.e. one or more cellulose blank(s) at a time.

[0008] The technical field of dry manufacturing rigid cellulose products having non-flat general shape, such as trays, lids, or the like, i.e. wherein the forming / pressing is performed in one step using a cyclic moulding tool having a first / male mould part and a second / female mould part configured to cooperate with each other, is well known. A major benefit of having discrete cellulose blanks is that the amount of scrap material is drastically decreased or entirely avoided. However, the sub-technical field of reliably feeding of discrete cellulose blanks from a continuous flow of discrete cellulose blanks into a cyclically operated moulding tool is still exposed to challenges.

[0009] During moulding / forming of the rigid cellulose product having non-flat general shape from the more or less flat cellulose blank, material draw and elongation in the cellulose blank will take place during closing of the moulding tool, i.e. insertion of the male mould part into the female mould part. Especially for deep cellulose products, cracks are prone to arise at the transitional edge regions between the bottom and the wall and thereby the possible product shapes that can be manufactured is limited. Due to the fluffy characteristics of the discrete cellulose blanks, not only the design of the moulding tool will have effect on the risk of crack generation, but also the handling / transfer of the cellulose blanks into the moulding tool will have negative effect on the risk of crack generation if not properly organized / performed.

[0010] Thus, there is still a need in the art for a reliable, cheap and unharmful dry-forming technique / process for dry manufacturing rigid cellulose products having non-flat general shape, wherein the pressed cellulose products are protected from damage that otherwise would originate from the feeding of delicate cellulose blanks into the moulding tool.Object of the Invention

[0011] The present invention aims at obviating the aforementioned and other disadvantages and failings of previously known methods and devices for dry manufacturing rigid cellulose products, and at providing an improved apparatus and method for dry manufacturing rigid cellulose products having non-flat general shape, wherein reliable feeding of discrete cellulose blanks from a continuous flow of discrete cellulose blanks into a cyclically operated moulding tool is secured.

[0012] A primary object of the present invention is to provide an improved apparatus and method for dry forming / manufacturing rigid cellulose products having non-flat general shape, wherein the environmental benefits as well as time and energy saving benefits of conventional dry-forming techniques are maintained. It is another object of the present invention to provide an improved product forming unit and method for dry forming / manufacturing rigid cellulose products having non-flat general shape, wherein the pressed cellulose products are protected from damages originating from the step of feeding the cellulose blank from the conveyor structure into the forming mould.Summary of the Invention

[0013] According to the invention at least the primary object is attained by means of the initially defined apparatus and method having the features defined in the independent claims. Preferred embodiments of the present invention are further defined in the dependent claims.

[0014] According to a first aspect of the present invention, there is provided a apparatus of the initially defined type, wherein that apparatus further comprises an in-feed device that comprises a movable arm and a suction device connected to said arm, wherein the suction device is configured to engage and transfer the cellulose blank from the continuously moving conveyor belt into the open moulding tool of the product forming unit, the suction device having a perforated area corresponding in size to at least the product area of the cellulose blank, wherein the suction device in the transport direction of the conveyor arrangement during engagement with the cellulose blank, is configured to move in conformity with the traveling speed of the conveyor belt.

[0015] According to a second aspect of the present invention, there is provided a method of the initially defined type, wherein the step of transferring the cellulose blank from the conveyor arrangement into the open moulding tool, comprises the steps of providing an in-feed device that comprises a movable arm and a suction device connected to said arm, and engaging the cellulose blank by means of the suction device, the suction device having a perforated area corresponding in size to at least the product area of the cellulose blank, wherein the suction device in the transport direction of the conveyor arrangement is moved in conformity with the traveling speed of the conveyor belt during engagement with the cellulose blank.

[0016] Thus, the present invention is based on the insight that it is of uttermost importance to have control of the location and operation of the in-feed device in order to secure reliable engagement and transfer of the cellulose blank without damaging the delicate cellulose blank during the step of transferring the cellulose blanks from the conveyor arrangement into the moulding tool. Thus, the inventors have realized that by having full engagement between the suction device and the part of the cellulose blank that will be formed into the rigid cellulose product, and by having no mutual movement between the cellulose blank and the suction device during the engagement, will secure that the delicate cellulose blank will not be damaged during the transfer from the continuously moving conveyor belt into the moulding tool.

[0017] The present invention, i.e. the engagement / contact between the entire product area of the cellulose blank and the suction device and the synchronised movement of the suction device and the cellulose blank during engagement, provides the advantage that the delicate cellulose blank is not damaged during the transfer and thereby the risk of generation of cracks is decreased. Thus, rate of successful transfer of undamaged cellulose blanks will increase.

[0018] According to various example embodiments of the present invention the step of engaging the cellulose blank by means of the suction device, comprises the steps of: hovering the suction device above the conveyor belt without contacting the cellulose blank, increasing the speed of the suction unit in the transport direction of the conveyor arrangement, displacing at least one of the suction unit and the conveyor belt towards the other, contacting the cellulose blank by means of the suction device when the speed of the suction device in the transport direction of the conveyor arrangement is equal to the traveling speed of the conveyor belt, and activating the suction device when the suction device is in contact with the cellulose blank.

[0019] Thereby the loosely connected cellulose fibres of the cellulose blank will remain a uniform cellulose blank during and after the transfer into the moulding tool.

[0020] According to various example embodiments of the present invention the cellulose blank is retained on the continuously moving conveyor belt by means of an air-removing arrangement configured to pull the cellulose blank towards the conveyor belt, and wherein the air-removing arrangement is not active at the position the suction device engages the cellulose blank. Thereby the entire cellulose blank will be securely transferred from the conveyor arrangement to the in-feed device without any risk for flaking / lamination of the delicate cellulose blank.

[0021] According to various example embodiments of the present invention the in-feed device is connected to a low-pressure source via a conduit extending from the low-pressure source to the in-feed device, wherein the suction device of the in-feed device comprises a chamber that is in constant fluid communication with a plurality of apertures that are arranged in the perforated area of the suction device, wherein the in-feed device comprises a controllable valve located between the conduit and the chamber. Thereby the system response time between deactivated and activated suction device is minimized, entailing a minimized risk of not having correct engagement before lifting the cellulose blank and entailing a faster transferring procedure from the conveyor arrangement into the moulding tool.

[0022] Further advantages with and features of the invention will be apparent from the following detailed description of preferred embodiments.Brief description of the drawings

[0023] A more complete understanding of the abovementioned and other features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments in conjunction with the appended drawings, wherein: Fig. 1is a schematic illustration of a production line or apparatus for dry manufacturing rigid cellulose products, Fig. 2is a schematic illustration of a moulding tool, wherein a cellulose blank is provided into the moulding tool between the first / female mould part and the second / male mould part, Fig. 3is a schematic illustration of the moulding tool according to figure 2 during forming / pressing of the cellulose product, Fig. 4is a schematic illustration of the moulding tool according to figures 2 and 3 after the forming / pressing step and the pressed cellulose product is released from the moulding tool, Fig. 5is a schematic illustration of the pressed cellulose product according to figure 4, wherein the scrap area is removed from the final cellulose product, Fig. 6is a schematic illustration of an inventive apparatus, wherein the in-feed device engages the cellulose blank, Fig. 7is a schematic illustration of the apparatus according to figure 6, wherein the in-feed device moves the cellulose blank into the moulding tool, Fig. 8is a schematic illustration of the apparatus according to figures 6 and 7, wherein the in-feed device releases the cellulose blank in the moulding tool, Fig. 9is a schematic cross-sectional side view of the in-feed device, Fig. 10is a schematic view from above of a cellulose blank, Fig. 11is a schematic view from below of a first schematic embodiment of the in-feed device, Fig. 12is a schematic view from below of a second schematic embodiment of the in-feed device, Fig. 13is a schematic view from below of a third schematic embodiment of the in-feed device, Fig. 14is a schematic illustration of an out-feed device, wherein the out-feed device is inserted into the moulding tool between the first / female mould part and the second / male mould part, and Fig. 15is a schematic illustration of the out-feed device according to figure 14, wherein the out-feed device together with the cellulose product are removed from the moulding tool. Detailed description of preferred embodiments of the invention

[0024] As used herein, the term "air / dry moulding / forming or air / dry laying / laid" means a well-known method according to which separated cellulose fibres are formed into a cellulose blank / sheet.

[0025] In air-laying technique, small / short fibres having a normal length in the range of 0,5 to 70 mm, for instance 1 to 10 mm, are separated and captured by an air stream / flow, and then laid on / applied to a forming mesh / surface, usually using a low pressure at the other side of the mesh / surface. The general terms "air / dry laying" and "air / dry moulding" are used interchangeably herein. The cellulose fibre carrying air flow may be generated by suitable device located upstream and / or downstream the forming mesh / surface.

[0026] Reference is initially made to figures 1 and 5, wherein figure 1 disclose a schematic illustration of a generic production line / apparatus for dry manufacturing rigid cellulose products, wherein said apparatus is generally designated 1. The production line 1 is configured for manufacturing rigid cellulose products, generally designated 2, having essentially non-flat general shape from separated cellulose fibres. Such a production line 1 may be arranged and set-up according to different well-known ways. Figure 5 disclose an example of a rigid cellulose product / tray 2. The apparatus 1 may have automatic transfer / handling between the different process steps, and / or may have manual transfer / handling between the different process steps, and thereto the apparatus 1 may have intermediate storing and / or additional process steps between the disclosed process steps, and / or the process steps may be located at different sites.

[0027] Figure 5 disclose an example of a rigid cellulose product 2 in the shape of a tray / container, wherein the tray is formed using the inventive method. The tray 2 comprises an inclined circumferential wall 3 and an opening 4 defined by a circumferential rim / brim 5 connected to the upper / free end of the wall 3. According to figure 5 embodiment the brim 5 has an angled shape having an essentially radially extending upper surface and a turned-down outer edge, however it shall be pointed out that the cross-section of the brim 5 may have other shapes. The tray 2 may have truncated cone shape having straight wall 3, narrowing in the direction away from the opening 4, in accordance with figure 5 embodiment. The tray 2 may for instance have curved-shaped wall 3 seen in the axial plane. By having inclined walls 3 multiple trays 2 are stackable one inside the other when they are empty. The tray could also be a mug / cup, a lid, packaging or the like container / product. The cross section of the circumferential wall 3 in the radial plane may have any suitable shape, circular, oval, rectangular, polygonal, etc., and may differ in shape and / or dimension along the axial extension of the tray 2. The tray 2 comprises a bottom 6, wherein the bottom 6 is entirely flat or the bottom may comprise local ribs, projections, etc., for strength and rigidity of the cellulose product. The bottom 6 may be located at the very lower end of the wall 3, according to figure 5 embodiment, and / or be partly located at an axial distance from the lower end of the wall 3, or a combination thereof. The circumferential wall 3 is connected to and extends in the axial direction upwards from the bottom portion 6.

[0028] Cellulose raw material 7, i.e. comprising mainly the cellulose part of organic matter, is provided to the production line, and is fed to a separating / disintegrating unit 8 in order to obtain individualized / separated cellulose fibres. The separated cellulose fibres are thereafter transported by an air stream / flow to a dispenser of a cellulose blank / sheet forming unit 9. The cellulose fibres are laid by the dispenser on a moving or stationary perforated surface of the cellulose blank forming unit 9. The cellulose fibre carrying air flow may be generated by suitable device located upstream and / or downstream the perforated surface. Thereafter the generated cellulose blank, generally designated 10, is transported / transferred to a product forming unit 11, whereby rigid cellulose products 2 are formed and discharged from the product forming unit 11.

[0029] The cellulose blank forming unit 9 may be configured to generate a continuous cellulose blank / web 10 and / or discontinuous / discrete cellulose blanks 10. Discontinuous / discrete cellulose blanks 10 are fed into the product forming unit 11.

[0030] The cellulose raw material 7 may be in the form of reeled pulp or paper, bale of cellulose pulp, paper, etc. and / or sheets of paper, cellulose pulp, etc. In case said cellulose raw material 7 is in the form of sheets and / or reeled pulp or paper, it can be fed directly into the separating unit 8. However, in case said cellulose raw material 7 is in the form of a bale or compact stacks of sheets, etc. one or more shredders and / or one or more additional separating / disintegrating units 8 may be necessary to be used for separating and dosing said cellulose raw material 7 from said bale or sheets in smaller quantities. The shredder(s) prepare cellulose raw material 7 to be accepted by said separating unit 8. The separating unit 8 disintegrates the cellulose raw material 7 into separated cellulose fibres. Said one or plurality of shredder(s) are arranged before said one or a plurality of separating unit(s) 8, so that an output of one of said shredder is connected to an input of one of said separating units 8. The shredders may be arranged in parallel to each other or in series with each other, and the disintegrating units 8 may be arranged in parallel to each other or in series with each other. The shredders and the disintegrating units 8 together constitute a cellulose fibre separating unit, arranged upstream the cellulose blank forming unit 9.

[0031] Said cellulose raw material 7 may be constituted by virgin cellulose fibres and / or recycled cellulose fibres and may originate from wood pulps such as kraft pulp, sulphite pulp, mechanical pulp, thermomechanical pulp (TMP), chemical treated mechanical pulp, chemi-thermomechanical pulp (CTMP), and / or from non-wood pulps such as bagasse, bamboo, abaca, hemp, flax, cotton.

[0032] The separating unit 8 may according to various embodiments be constituted by a hammer mill. In said separating unit 8 the cellulose raw material is separated into fibres having a normal length in the range of 0,5-70 mm, preferably less than 10 mm. The length of said fibres may be customized by adjusting the internal properties of the separating unit 8 and / or by choosing a different separating unit 8 and / or choosing different cellulose raw material 7. The fibre length for wood pulp is according to various embodiments in the range 0,5-4 mm, preferably in the range 1,7-3,6 mm. According to various embodiments the fibre length for non-wood pulp is in the range 0,5-70 mm.

[0033] The production line 1 may comprise a pre-compression and / or imprinting unit 12, located downstream the cellulose blank forming unit 9 and upstream the product forming unit 11. In the pre-compression and / or imprinting unit 12, an air-laid fluffy cellulose blank 10 having a first thickness may be compressed into a cellulose blank 10 having a second thickness, wherein said second thickness is thinner than said first thickness, and / or may be provided with an imprinting pattern. During the pre-compression / imprinting the cellulose blank is made more coherent and easier to handle, since the pre-compression / imprinting generates internal bindings between individual cellulose fibres preventing mutual separation of the cellulose fibres.

[0034] The product forming unit 11 comprises a press unit 13, and may optionally comprise a pre-heating unit 14 arranged upstream the press unit 13. According to various example embodiments said cellulose blank 10 may be heated to an elevated temperature before being fed into the press unit 13 of the product forming unit 11. In such embodiment(s) where the cellulose blank 10 is preheated before being fed into the press unit 13, said press unit 13 may or may not comprise heating. According to various example embodiment said press unit 13 may be a heated press unit 13 for heating said cellulose blank 10 during pressing. In the case of a heated press unit 13, preheating of said cellulose blank 10 using a pre-heating unit 14 is optional. According to various example embodiments preheating of the cellulose blank 10 in said pre-heating unit 14 may be combined with a heated press unit 13. Having a pre-heating unit 14 in combination with a heated press unit 13 will speed up the manufacturing process in the product forming unit 11, and improve the quality / rigidity of the final rigid cellulose product 2. In the product forming unit 11 the cellulose blank 10 is heated to a temperature in the range 120 - 200 °C in order to obtain adequate rigidity and strength in the final cellulose product 2.

[0035] Reference is now made to figures 2-4. The press unit 13 comprises a moulding tool having a first mould part 15 and a second mould part 16 having co-operating designs, wherein at least one of the first mould part 15 and the second mould part 16 is / are displaceable in the axial direction in relation to each other, i.e. reciprocating back and forth in relation to each other, in order to exert pressure to the cellulose blank 10 loaded therebetween. In the figures the mutual displacement is disclosed as being vertical, however the mutual displacement may be horizontal or any other suitable angle. The cellulose blank 10 loaded into the moulding tool, is constituted by the air-laid cellulose blank 10. The air-laid cellulose blank 10 may be generated upstream the product forming unit 11 in the same apparatus / production line and provided / transferred to the product forming unit 11, or may be generated at a separate location and provided / transferred to the product forming unit 11 via intermediate handling and storage.

[0036] According to various embodiments the first mould part 15 of the moulding tool is a female mould part, i.e. having a main recess 17 for receiving a major part of the cellulose blank 10, and the second mould part 16 of the moulding tool is a male mould part, i.e. having a main protrusion 18 for cooperation with said recess 17 of the female mould part by being inserted therein, such that the cellulose blank 10 is pressed into a final rigid non-flat shape by applying a predetermined pressure P in the axial direction of the moulding tool. According to the disclosed embodiment the male mould part 16 is located above the female mould part 15, but according to alternative embodiments the female mould part may be the second mould part and may be located above the male mould part which is then the first mould part. The pressed cellulose product 2 is intended to remain in / on the first mould part 15 after the pressing of the cellulose product 2, irrespective of the angular orientation of the moulding tool.

[0037] In the disclosed schematic embodiment, the male / second mould part 16 comprises a product press-surface and a scrap press-surface surrounding the product press-surface, and the female / first mould part 15 also comprises a product press-surface and a scrap press-surface surrounding the product press-surface. The cellulose blank 10 is pressed between the product press-surfaces of the first and second mould parts, respectively, into final shape.

[0038] The mutual distance, taken perpendicular to the surface in question, between the product press-surface of the female / first mould part 15 and the product press-surface of the male / second mould part 16 during the pressing of the cellulose blank 10 is T millimetres, wherein T preferably is in the range 0,2-2,5 millimetres, i.e. equal to the thickness of the bottom 6 of the pressed cellulose product 2. Preferably, T is in the range 0,3-1,5 millimetres. The wall surfaces of the moulding tool have to be inclined in order to obtain a release angle for the cellulose product, and in order to obtain adequate press force to the wall region 3 of the cellulose product 2.

[0039] At the scrap area of the moulding tool, the mutual distance between the scrap press-surface of the first mould part 15 and the scrap press-surface of the second mould part 16 is equal to or more than the mutual distance between the product press-surface of the first mould part 15 and the product press-surface of the second mould part 16. The part of the cellulose blank 10 located at the scrap area may be left entirely uncompressed in the moulding tool, be partially compressed by applying a predetermined partial pressure less than said predetermined pressure P, or be fully compressed by applying said predetermined pressure P. Thus, radially outside the final rigid cellulose product 2, the cellulose blank 10 comprises a scrap area intended to be cut off. In figure 4 the cellulose product 2 is released and schematically removed from the moulding tool by opening the moulding tool. Figure 5 disclose a schematic illustration of a cellulose tray 2 wherein the scrap 19 is cut off from the cellulose tray 2. The scrap 19 may be removed in a separate step in the moulding tool, in a subsequent step outside the moulding tool after the pressing of the cellulose product 2, or in a step concurrent with the pressing of the cellulose product 2.

[0040] According to various embodiments, the moulding tool do not comprise scrap press-surfaces, but the cellulose product 2 is formed in its final design without need for cutting / trimming.

[0041] According to various embodiments. When the compartment of the rigid cellulose tray 2 is filled with objects, a film / cover / lid may be attached to the circumferential rim / brim 5 of the cellulose tray 2, for instance using heat lamination. The lid film may be constituted by a multilayer film comprising polymer, metal, and / or paper.

[0042] According to various embodiments. Before any items are placed in the compartment of the rigid cellulose tray, the rigid cellulose tray 2 may be provided with a liner film adhered to at least to the circumferential rim / brim 5, and preferably also to the wall 3 and / or the bottom 6 of the cellulose tray 2. The liner film may be constituted by a multilayer film comprising polymer and / or metal. The adhesion of the liner film to the tray is preferably heat activated.

[0043] According to various embodiments, the cellulose blank 10 may comprise barrier additives and / or material property enhancing additives, etc., such that the rigid cellulose tray 2 withstand grease, fat, water, vapour, etc. The additives are preferably provided to the cellulose fibers upstream the disintegrating unit 8 or between the disintegrating unit 8 and the product forming unit 11.

[0044] The predetermined pressure P is in the range 40-10000N / cm 2< , preferably in the range 100-4000N / cm 2< . According to various embodiments said predetermined pressures are above 1000 N / cm 2< , and according to various embodiments said predetermined pressures are below 2500 N / cm 2< . The holding time during the pressing step is in equal to or more than 1 second and equal to or less than 10 seconds, preferably less than 5 seconds, and most preferably less than 3 seconds.

[0045] Reference is now especially made to figures 6-8 disclosing a schematic embodiment of the inventive apparatus 1. The apparatus 1 comprises a conveyor arrangement, generally designated 20. The conveyor arrangement 20 is configured to receive cellulose blanks 10 in a continuous stream from the cellulose blank forming unit 9, and transporting the continuous stream of cellulose blanks 10 in a transport direction towards the product forming unit 11. The separating / disintegrating unit 8 and the cellulose blank forming unit 9 are schematically disclosed, at the upstream end of the conveyor arrangement 20. According to alternative embodiments the cellulose blanks 10 are provided to the conveyer arrangement 20 from an intermediate storage, manually or automatically.

[0046] The conveyor arrangement 20 comprises an endless conveyor belt 21 that is continuously moving during operation of the apparatus 1, and has a predetermined traveling speed in the transport direction of the conveyor arrangement 20. The traveling speed of the conveyor belt 21 is preferably adjustable, and is adjusted in consensus with the cycle rate of the product forming unit 11, and also in consensus with the cycle rate of the cellulose forming unit 9 when applicable. The traveling speed of the conveyor belt 21 is also dependent on the size of the cellulose blanks 10 in relation to the size of the mutual gap between the cellulose blanks 10.

[0047] The apparatus 1 further comprises an in-feed device, generally designated 22, configured for transferring the cellulose blank 10 from the conveyor arrangement 20 and loading the cellulose blank 10 into the moulding tool that is open and empty. Reference is now also made to figures 2 and 9, partly disclosing a schematic embodiment of the in-feed device 22. The in-feed device 22 comprises a movable arm 23 and a suction device 24 connected to said arm 23. Figure 10 disclose a schematic embodiment of a cellulose blank 10 having a product area 25 and a circumferential scrap area 26. According to alternative embodiments the cellulose blank 10 does not comprise a scrap area 26. The product area 25 of the cellulose blank 10 is intended to be pressed between the product press-surfaces of the moulding tool, i.e. is intended to constitute the pressed cellulose product 2. One purpose of the scrap area 26 is to secure that the product area 25 of the cellulose blank 10 has uniform / intended density since it is hard to obtain uniform / intended density all the way out to the edges of the cellulose blank 10 in the cellulose blank forming unit 9.

[0048] The suction device 24 has a perforated area 27 corresponding in size to at least the product area 25 of the cellulose blank 10. The suction device 24 is configured to engage and transfer the cellulose blank 10 from the continuously moving conveyor belt 21 into the open moulding tool. Thus, the entire product area 25 of the cellulose blank 10 shall be firmly engaged by the suction device 24, i.e. by means of the perforated area 27, in order to prevent material draw, internal cracks or fibre-fibre separations in the cellulose blank 10 during transfer of the cellulose blank 10 into the moulding tool. Thus, a uniform / intendent material characteristics of the cellulose blank 10 is secured, which will provide the best conditions for preventing cracks in the final cellulose product 2 originating during the pressing of the cellulose blank 10.

[0049] In figure 6, the suction device 24 of the in-feed device 22, in the transport direction of the conveyor arrangement 20, is moved in conformity with the traveling speed of the conveyor belt 21 during engagement with the cellulose blank 10. Thus, the suction device 24 has the same speed as the cellulose blank 10 when the suction device 24 contacts and grasps / engage the cellulose blank 10. About the same time as the in-feed device 22 engages the cellulose blank 10, the preceding press cycle in the product forming unit 11 is finished and the moulding tool of the product forming unit 11 is opened. If the speed of the suction device 24 is different than the traveling speed of the conveyor belt 21 when the suction device 24 contacts the cellulose blank 10, there is a risk that the mutual movement between the suction device 24 and the conveyor belt 21 will damage the cellulose blank 10 clamped therebetween.

[0050] According to various embodiments, before the suction device 24 of the in-feed device 22 contacts the cellulose blank 10, the suction device 24 hovers above the conveyor belt 21 and above the cellulose blanks 10, i.e. not contacting the cellulose blanks 10. The hovering of the suction device 24 may be stationary at a start position and / or may be constituted by a return motion of the in-feed device 22 from the moulding tool to the start position. From the start position, the speed of the suction device 24 in the transport direction of the conveyor arrangement 20 is increased. Concurrently, at least one of the suction device 24 and the conveyor belt 21 is / are displaced towards the other, in order to decrease the distance between the suction device 24 and the cellulose blank 10. When the speed of the suction device 24 in the transport direction is equal to the traveling speed of the conveyor belt 21 and the cellulose blank 10, the suction device 24 contacts the cellulose blank 10. When the suction device 24 is in contact with the cellulose blank 10, the suction device 24 is activated. A too early activation of the suction device 24, i.e. before contact between the suction device 24 and the cellulose blank 10, entails a risk that the orientation of the cellulose blank 10 is changed and thereby an incorrect loading of the cellulose blank 10 into the moulding tool.

[0051] In figure 7, the in-feed device 22 transfers the cellulose blank 10 into the moulding tool, and concurrently the pressed cellulose product 2 from the preceding press-cycle is removed from the moulding tool. According to the disclosed embodiment the moulding tool is located in the transport direction of the conveyor arrangement 20. According to alternative embodiments, the moulding tool is located at the side of the conveyor arrangement 20, i.e. in the transverse direction, seen in relation to the transport direction of the conveyor arrangement 20. Thereby, the apparatus may comprise one or more moulding tools on each side of the conveyor arrangement 20.

[0052] According to various embodiments, after the suction device 24 has grasped / engaged the cellulose blank 10, at least one of the suction device 24 and the conveyor belt 21 is / are displaced away from the other. Thereafter the cellulose blank 10 is transferred into the moulding tool. According to the disclosed embodiment, the speed of the suction device 24 in the transport direction of the conveyor arrangement 20 is increased to exceed the traveling speed of the conveyor belt 21. In order to have time to transfer the cellulose blank 10 into the moulding tool and return the in-feed device 22 to the start position, before it is time to engage the next cellulose blank 10.

[0053] In figure 8, the suction device 24 of the in-feed device 22 releases the cellulose blank 10 in the open moulding tool, by deactivating the suction device 24. According to alternative embodiments, the cellulose blank 10 may also be blown off from the suction device 24 in order to secure proper release.

[0054] According to various embodiments, the cellulose blank 10 is transferred into contact with the first mould part 15 by means of the suction device 24 before the cellulose blank 10 is released from the suction device 24. According to various embodiments, the in-feed device 22 may be used to pre-form the cellulose blank 10 into the main recess 17 of the first mould part 15 when releasing the cellulose blank 10 in contact with the first mould part 15. By releasing the cellulose blank 10 in contact with the first mould part 15, the orientation and location of the cellulose blank 10 is under control, which will guarantee an optimal forming of the cellulose product 2 in the moulding tool.

[0055] According to various embodiments, the cellulose blank 10 is retained on the continuously moving conveyor belt 21 by means of an air-removing arrangement 28, i.e. a fan, configured to pull the cellulose blank 10 towards the conveyor belt 21, i.e. by means of under-pressure condition. Thereby the orientation and location of the cellulose blank 10 is known and fixed, in relation to the moving conveyor belt 21. However, the air-removing arrangement 28 is not active at the position the suction device 24 engages the cellulose blank 10 and lifts the cellulose blank 10 from the conveyor belt 21, e.g. by means of a box / partition 29, or reduced. This part of the conveyor belt 21 is also called pick-up zone. If a too extensive under-pressure is active when lifting the cellulose blank 10 from the conveyor belt 21, the cellulose blank 10 may become damaged, i.e. one segment / layer of the cellulose blank 10 is in engagement with the suction device 24 and one segment / layer of the cellulose blank 10 is still in engagement with the conveyor belt 21. According to various embodiments, the conveyor arrangement 20 may comprise over-pressure in the box 29, in order to secure proper transfer of the cellulose blank 10 from the conveyor belt 21 to the suction device 24. According to alternative embodiments, there is under-pressure condition in the pick-up zone when the cellulose blank 10 enters the pick-up zone in order to keep the cellulose blank 10 in the correct orientation and position until the suction device 24 contacts the cellulose blank 10. Before the suction device 24 lifts the cellulose blank 10 from the conveyor belt 31, the under-pressure condition in the pick-up zone is removed / deactivated or at least reduced.

[0056] According to various embodiments, the in-feed device 22 is connected to a low-pressure source 30 via a conduit 31 extending from the low-pressure source 30 to the in-feed device 22. Furthermore, the suction device 24 the in-feed device 22 comprises a chamber 32 that is in constant fluid communication with a plurality of apertures that are arranged in the perforated area 27 of the suction device 24. Thus, when there is an under-pressure in the chamber 32, i.e. the suction device 24 is activated, the cellulose blank 10 is sucked / forced against the perforated area 27, and when there is ambient-pressure or over-pressure in the chamber 32, i.e. the suction device 24 is deactivated, the cellulose blank 10 is released from the perforated area 27. The in-feed device 24 comprises a controllable valve 33 located between the conduit 31 and the chamber 32, in order to activate / deactivate the suction device 24. By having the controllable valve 33 located in close vicinity to the chamber 32, the response-time from inactive to active suction device 24 is minimized. The chamber 32 shall be as small as possible, and the height of the chamber 32 is preferably in the range 0,5-2 centimetres. A too large height of the chamber 32 will prolong the response-time due to increased volume, and a too small height of the chamber 32 will prolong the response-time due to bottle-neck choking effect. According to various embodiments, when the under-pressure condition in the suction device 24 is turned off, the chamber 32 is at the same time connected to ambient air and / or a high-pressure source in order to further decrease the response-time.

[0057] Reference is now made to figures 11-13, disclosing different schematic embodiments of the underside of the suction device 24 of the in-feed device 22. According to the first embodiment disclosed in figure 11, the in-feed device 22 is configured to engage one cellulose blank 10 at the time, i.e. the suction device 24 comprises one perforated area 27 that corresponds in size / shape to at least the product area 24 of the cellulose blank 10. The transport direction of the conveyor arrangement 20 is from left to right, and thereby the conveyor belt 21 transports one row of cellulose blanks 10. If the perforated area 27 should be smaller than the product area 25 of the cellulose blank 10, there is a risk that the edges of the cellulose blank 10 will hang down and the loading of the cellulose blank 10 in the moulding tool might be incorrect, i.e. the cellulose blank 10 becomes partly double folded.

[0058] According to the second embodiment disclosed in figure 12, the in-feed device 22 is configures to engage two parallel cellulose blanks 10 at the time, i.e. the suction device 24 comprises two perforated areas 27, each corresponds in size / shape to at least the product area 25 of one cellulose blank 10. The transport direction of the conveyor arrangement 20 is from left to right, and thereby the conveyor belt 21 transports two parallel rows of cellulose blanks 10.

[0059] According to the third embodiment disclosed in figure 13, the in-feed device 22 is configures to engage two subsequent cellulose blanks 10 at the time, i.e. the suction device 24 comprises two perforated areas 27, each corresponds in size / shape to at least the product area 25 of one cellulose blank 10. The transport direction of the conveyor arrangement 20 is from left to right, and thereby the conveyor belt 21 transports one row of cellulose blanks 10.

[0060] According to the second and third embodiment, the moulding tool is configured to press multiple cellulose blanks 10 at the time. It shall be pointed out that the second and third embodiments may be combined in order to have a matrix of a plurality of perforated areas 27, wherein the matrix comprises a plurality of rows and a plurality of columns.

[0061] Reference is now made to figures 14 and 15, disclosing a schematic embodiment to remove the pressed cellulose product 2 from the moulding tool.

[0062] Figures 14 and 15 disclose the moulding tool and an out-feed device, generally designated 34 and schematically illustrated. The out-feed device 34 is configured to remove the pressed cellulose product 2 from the moulding tool in order to make the moulding tool empty and ready for the loading of the next cellulose blank 10. Thus, part of the out-feed device 34 is insertable into the moulding tool between the male / second mould part 16 and the female / first mould part 15 after the pressing of the cellulose blank 10. Thus, the pressed cellulose product 2 is intended to be located in / on the first mould part 15 after the pressing of the cellulose blank 10, and after the moulding tool is opened. Thereto, the out-feed device 34 may be arranged to transfer the pressed cellulose product 2 to a subsequent step in the apparatus such as trimming of the scrap 19 and / or stacking. According to the invention, the out-feed device 34 makes use of a pneumatic arrangement to grasp / engage and release the cellulose product 2. The out-feed device 34 comprises a movable arm 35 that is mechanically controlled and operated, e.g. a robotic arm, and a suction device 36 connected to the arm 35. The suction device 36 is insertable into the moulding tool between the male / second mould part 16 and the female / first mould part 15, and the suction device 36 is preferably inserted into the moulding tool during the opening of the moulding tool, i.e. when the male mould part 16 and / or the female mould part 15 are traveling away from each other after the pressing of the cellulose blank 10. By starting the insertion of the suction device 36 already before the moulding device is fully open, the press-cycle time may be decreased, i.e. as long as the different members does not collide. A low pressure level entails that the suction device 36 engage / holds the cellulose product 2, and a high pressure level entails that the suction device 36 ejects / drops the cellulose product 2. Alternatively, normal / ambient air pressure is used in order to drop the cellulose product 2.Feasible modifications of the Invention

[0063] The invention is not limited only to the embodiments described above and shown in the drawings, which primarily have an illustrative and exemplifying purpose. This patent application is intended to cover all adjustments and variants of the preferred embodiments described herein, thus the present invention is defined by the wording of the appended claims and the equivalents thereof. Thus, the equipment may be modified in all kinds of ways within the scope of the appended claims.

[0064] Throughout this specification and the claims which follows, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or steps or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0065] It shall also be pointed out that it shall be considered understood that features from a specific embodiment disclosed herein can be combined with and / or exchanged by features from another embodiment and the combination obvious, even though not expressly taught, when the combination and / or exchange is possible.

Claims

1. Method for dry manufacturing rigid cellulose product (2) having essentially non-flat general shape from a cellulose blank (10), using an apparatus (1) having a product forming unit (11) that comprises a moulding tool having a first mould part (15) and a second mould part (16), wherein at least one of the first mould part (15) and the second mould part (16) is displaceable in an axial direction in relation to the other in order to press the cellulose blank (10) therebetween into final shape, wherein the cellulose blank (10) comprises a product area (25), the method comprising the steps of: - providing the cellulose blank (10) onto an endless conveyor belt (21) of a conveyor arrangement (20), wherein the conveyor belt (21) is continuously moving and has a predetermined traveling speed in a transport direction of the conveyor arrangement (20), - transferring the cellulose blank (10) from the conveyor arrangement (20) into the open moulding tool, and - forming rigid cellulose product (2) having essentially non-flat general shape from the cellulose blank (10) in the moulding tool by applying a predetermined pressure P in the axial direction of the moulding tool, the method being characterized in that the step of transferring the cellulose blank (10) from the conveyor arrangement (20) into the open moulding tool, comprises the steps of: - providing an in-feed device (22) that comprises a movable arm (23) and a suction device (24) connected to said arm (23), and - engaging the cellulose blank (10) by means of the suction device (24), the suction device (24) having a perforated area (27) corresponding in size to at least the product area (25) of the cellulose blank (10), wherein the suction device (24) in the transport direction of the conveyor arrangement (20) is moved in conformity with the traveling speed of the conveyor belt (21) during engagement with the cellulose blank (10).

2. The method according to claim 1, wherein the step of providing the cellulose blank () onto an endless conveyor belt (21) of a conveyor arrangement (20), comprises the steps of: - providing a quantity of separated cellulose fibres by disintegrating a cellulose-based raw material (7), - forming a cellulose blank (10) from said quantity of separated cellulose fibres transported by an air flow, and - providing the cellulose blank (10) onto the endless conveyor belt (21).

3. The method according to claim 1 or 2, wherein the step of engaging the cellulose blank (10) by means of the suction device (24), comprises the steps of: - hovering the suction device (24) above the conveyor belt (21) without contacting the cellulose blank (10), - increasing the speed of the suction device (24) in the transport direction of the conveyor arrangement (20), - displacing at least one of the suction device (24) and the conveyor belt (21) towards the other, - contacting the cellulose blank (10) by means of the suction device (24) when the speed of the suction device (24) in the transport direction of the conveyor arrangement (20) is equal to the traveling speed of the conveyor belt (21), and - activating the suction device (24) when the suction device (24) is in contact with the cellulose blank (10).

4. The method according to any preceding claim, wherein the step of transferring of the cellulose blank (10) from the conveyor arrangement (20) into the open moulding tool, further comprises the steps of: - displacing at least one of the suction device (24) and the conveyor belt (21) away the other, wherein the cellulose blank (10) is in engagement with the suction device (24), - transferring the cellulose blank (10) by means of the suction device (24) into the open moulding tool, and - releasing the cellulose blank (10) from the suction device (24) in the open moulding tool.

5. The method according to claim 4, wherein the step of transferring of the cellulose blank (10) from the conveyor arrangement (20) into the open moulding tool, after the step of displacing at least one of the suction device (24) and the conveyor belt (21) away the other, further comprises the step of: - increasing the speed of the suction device (24) in the transport direction of the conveyor arrangement (20) to exceed the traveling speed of the conveyor belt (21).

6. The method according to claim 4 or 5, wherein the step of transferring of the cellulose blank (10) from the conveyor arrangement (20) into the open moulding tool, before the step of releasing the cellulose blank (10) from the suction device (24) in the open moulding tool, further comprises the step of: - transferring the cellulose blank (10) into contact with the first mould part (15) by means of the suction device (24).

7. The method according to any preceding claim, wherein the cellulose blank () is retained on the continuously moving conveyor belt (21) by means of an air-removing arrangement (28) configured to pull the cellulose blank (10) towards the conveyor belt (21), and wherein the air-removing arrangement (28) is not active at the position the suction device (24) engages the cellulose blank (10).

8. The method according to any preceding claim, wherein the in-feed device (22) is connected to a low-pressure source (30) via a conduit (31) extending from the low-pressure source (30) to the in-feed device (22), wherein the suction device (24) of the in-feed device (22) comprises a chamber (32) that is in constant fluid communication with a plurality of apertures that are arranged in the perforated area (27) of the suction device (24), wherein the in-feed device (22) comprises a controllable valve (33) located between the conduit (31) and the chamber (32).

9. Apparatus for dry manufacturing rigid cellulose product (2) having essentially non-flat general shape from a cellulose blank (10), the apparatus (1) comprising: - a conveyor arrangement (20) comprising an endless conveyor belt (21) for receiving the cellulose blank (10), wherein the conveyor belt (21) is configured for continuously moving at a predetermined traveling speed in a transport direction of the conveyor arrangement (20), and - a product forming unit (11) that comprises a moulding tool having a first mould part (15) and a second mould part (16), wherein at least one of the first mould part (15) and the second mould part (16) is displaceable in an axial direction in relation to the other in order to press the cellulose blank (10) therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, wherein the cellulose blank (10) comprises a product area (25), characterized in that the apparatus (1) further comprises: - an in-feed device (22) that comprises a movable arm (23) and a suction device (24) connected to said arm (23), wherein the suction device (24) is configured to engage and transfer the cellulose blank (10) from the continuously moving conveyor belt (21) into the open moulding tool of the product forming unit (11), the suction device (24) having a perforated area (27) corresponding in size to at least the product area (25) of the cellulose blank (10), and wherein the suction device (24) in the transport direction of the conveyor arrangement (20) during engagement with the cellulose blank (10), is configured to move in conformity with the traveling speed of the conveyor belt (21).

10. The apparatus according to claim 9, wherein the apparatus (1) further comprises: - a disintegrating unit (8) for providing a quantity of separated cellulose fibres from a cellulose raw material (7), and - a cellulose blank forming unit (9) configured for forming a cellulose blank (10) from said quantity of separated cellulose fibres transported by an air flow from the disintegrating unit (8), wherein the cellulose blank forming unit (9) is configured to provide the cellulose blank (10) to the conveyor belt (21).

11. The apparatus (1) according to claim 9 or 10, wherein the cellulose blank (10) is composed of an air-laid cellulose blank.

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