CA2001299A1 - Method for the manufacture of load-carrying elements, including pallets - Google Patents
Method for the manufacture of load-carrying elements, including palletsInfo
- Publication number
- CA2001299A1 CA2001299A1 CA 2001299 CA2001299A CA2001299A1 CA 2001299 A1 CA2001299 A1 CA 2001299A1 CA 2001299 CA2001299 CA 2001299 CA 2001299 A CA2001299 A CA 2001299A CA 2001299 A1 CA2001299 A1 CA 2001299A1
- Authority
- CA
- Canada
- Prior art keywords
- mould
- accordance
- pulp
- fact
- fibre
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 69
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 46
- 239000000835 fiber Substances 0.000 claims abstract description 82
- 239000002994 raw material Substances 0.000 claims abstract description 52
- 239000000463 material Substances 0.000 claims description 45
- 230000008569 process Effects 0.000 claims description 26
- 239000002245 particle Substances 0.000 claims description 19
- 238000000151 deposition Methods 0.000 claims description 13
- 238000009837 dry grinding Methods 0.000 claims description 12
- 239000007858 starting material Substances 0.000 claims description 12
- 239000002131 composite material Substances 0.000 claims description 11
- 230000035699 permeability Effects 0.000 claims description 9
- 238000003825 pressing Methods 0.000 claims description 9
- 230000001427 coherent effect Effects 0.000 claims description 7
- 230000000694 effects Effects 0.000 claims description 7
- 239000011230 binding agent Substances 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 5
- 229910052729 chemical element Inorganic materials 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 230000001419 dependent effect Effects 0.000 claims description 2
- 230000004927 fusion Effects 0.000 claims description 2
- 239000003795 chemical substances by application Substances 0.000 claims 1
- 239000011246 composite particle Substances 0.000 claims 1
- 238000000465 moulding Methods 0.000 abstract description 10
- 238000001035 drying Methods 0.000 description 17
- 239000012071 phase Substances 0.000 description 16
- 238000000227 grinding Methods 0.000 description 11
- 230000027455 binding Effects 0.000 description 8
- 238000009739 binding Methods 0.000 description 8
- 239000003292 glue Substances 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000005755 formation reaction Methods 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- 239000010893 paper waste Substances 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 239000000047 product Substances 0.000 description 5
- 239000000725 suspension Substances 0.000 description 5
- 238000012546 transfer Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 238000007493 shaping process Methods 0.000 description 3
- 241000905957 Channa melasoma Species 0.000 description 2
- 239000004566 building material Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910052602 gypsum Inorganic materials 0.000 description 2
- 239000010440 gypsum Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 239000004129 EU approved improving agent Substances 0.000 description 1
- 229920001131 Pulp (paper) Polymers 0.000 description 1
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 210000003097 mucus Anatomy 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 235000002020 sage Nutrition 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- 230000003245 working effect Effects 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
- D21J7/00—Manufacture of hollow articles from fibre suspensions or papier-mâché by deposition of fibres in or on a wire-net mould
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Paper (AREA)
- Pallets (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
- Buffer Packaging (AREA)
Abstract
Procedure for the manufacture of load carrying elements, in-cluding pallets.
ABSTRACT
By means of a procedure for the manufacture of load carrying elements, including pallets, a fluidized fibre raw material is deposited on a moulding foundation through suction of a pulp of the fibre raw material on that foundation. For this purpose the foundation is applied with an easily drainable pulp created by the fluidized fibre raw material in such an amount and the suction is carried out controlled in such a way that on the foundation through suction a fibre raw ma-terial is deposited having such wall thickness that substan-tially provides the desired load capacity of the element.
(Fig. 16).
ABSTRACT
By means of a procedure for the manufacture of load carrying elements, including pallets, a fluidized fibre raw material is deposited on a moulding foundation through suction of a pulp of the fibre raw material on that foundation. For this purpose the foundation is applied with an easily drainable pulp created by the fluidized fibre raw material in such an amount and the suction is carried out controlled in such a way that on the foundation through suction a fibre raw ma-terial is deposited having such wall thickness that substan-tially provides the desired load capacity of the element.
(Fig. 16).
Description
~nq~
The present invention concerns a method for the manu-facture of load-carrying elements, including pallets by the depositing of a fluidized fibre raw matexial on a moulding foundation by suction of a pulp of the :Eibre raw material on this foundation.
A fluidized fibre raw material means a starting mate-rial, which may be in wet form, of ~ fibrous nature and suited for the manufacture of the deslred objects. Such starting material may for instance be a fibre pulp material as used for instance for trays and cartons for packaging of fragile and sensitive objects such as fruit, flowers, eg~s and objects of for instance glass. The pulp material usually consists of a suspended, fibrous cellulose.
It is well known for this purpose to use a production technique by which the starting material in the form of a pulp is by a depositing process placed against the outline-forming outside of a mould which is permeable to let a ga- ~, seous working medium, through a suction effect, affect the material through the material of the mould and thus mould the contour of the material on the mould through suction.
The object of the invention is to indicate how this in itself suitable production technique may be used not only to manufacture relatively small and light objects but also to manufacture large, rather heavy objects characterized by extremely high load capacity which are substantially based on a corresponding thickness of the material layer deposited on the moulding foundation. In comparison with this the wall thickness of the said small and light objects is rather thin and the rigidity necessary in practice is usually obtained by deliberately forming the wall panels which for instance support the said objects as the walls produce a rather rigid total object by mutually supporting each other.
According to the invention the stated objective is a-chieved by applying to the foundatio~ an easily drainable pulp made of the fluidized fibre raw material in such quan-tity and by controlling the suction in such a way that a fibre raw material layer of such thickness as to provide ~n~
substantially the load capacity desired for the element.
This will by using the above production technique also enable the manufacture of ~lements with high load capacity such as pallets and building elements which may, contrary to the said packaging examples, display rather even and smooth outer surface and which in itself displays a high de-gree of form stability. The depositing of a fibre raw mate-rial layer of the defined thickness means that the negative pressure in the fibre raw material layex used for suction may procure a material density which is highest at the out-side of the material layer directed towards the mould sur-face and which will have a reinforcing effect as it is placed at a distance from the through-going centre plan of the deposited object.
~5 By using the layer thickness of the element thus manu-factured its load capacity may according to the invention also be increased by procuring in the fibre raw material layer and distributed over this one or more variations in the layer thickness by correspondingly locally varying the suction effect during a joint suction process for the fibre pulp volume necessary for the manufacture of the whole ele-ment. In this way it will be possible in one and the same working process, i.e. the depositing of the fibre raw mate-rial on the moulding foundation, to mould both the final outside desired for the element and, by using the thickness of the material layer, a load capacity increasing moulded structure in the actual material object forming the element.
According to the invention such a structure will for in-stance be able to be shaped as a connected structural pat-tern with a thicker layer thickness compared with the partsof the element.
According to the invention a suitable way for the car-rying through of the method is characteristic in that, for suction of an easily drainable pulp of the fibre raw ma~te-rial in the desired thickness, a mould is used which at ne-gative pressure is permeable by a gaseous active working me-dium and which has a by the working medium permeable mould surface the perm~ability of which is adjusted to the thick-ness of the fibre raw material layer to be deposited b~ suc-tion of the pulp on this surface.
In this way it is possible to achieve such interaction between the draining ability of the pulp and the suction capability of the mould surface that also elements having thic~ fibre layer thickness owing to the desired load capa-city may be manufactured rationally.
In order to achieve local variations in the layer thickness of the fibre raw material layer of the element, a mould having a mould surface with a permeability varying in accordance with the layer thickness of the local varia-tion or variations respectively or the coherent structural pattern of the easily drainable fibre pulp layer deposited on the mould surface by suction may be used according to the invention.
This means that the depositing of fibre raw m~terial on the mould surface will vary according to the permeability of this surface which results in local variations in the suction effect which, in areas with poor mould surface per-meability, causes reduced depositing of fibre raw material in th.e mould surface whereas the depositing will be high in areas with high mould surface permeability.
~According to the invention, an embodiment of this me-:25 thod may be characterized by the use for suction of an easily drainable pulp of the fibre raw material in the de-sired thickness of a mould which at negative pressure is permeablQ by a gaseous active working medium which at least as regards the outline-forming part consists of a partial composite material the particles of which are fixed together for the formation of a contour-stable mould surface at the same time as they together limit passages open to the work-ing medium, which passages extend through the composite ma-terial to the outside surface of the mould, and that the thickness of at least the composite material layer forming the mould surface is adjusted according to the thickness of the fibre raw material layer to be deposited by suction of the pulp to this surface.
~J~?9~.2~
Such a mould may be manufactured on the basis of a cheap, inorganic raw material such as sand as well as by means of a produetion teehni~ue which is simple, of short duration and thus also cheap. The total produetion eosts o~
the mould may thus be kept at a low level and this form of construction will consequently be suitable for the produc-tion of a small number of products.
In order to achieve local variations in the layer thickness of the element's fibre raw material layer a mould may, according to the latter procedure, be used in which the composite material formed by the mould surface has a thiek-ness that varies in accordance with the layer thickness of the local variation or variations, respeetively, or the de-sired coherent structural pattern of the easily drainable fibre pulp la~er deposited on the mould surface by suction.
According to the invention a mould may be used the per-meable mould surface of which is composed of partieles with varying particle size, the particle size being small in the part forming the mould surface of the mould and larger in an underlying supporting layer for this part. In this way it is possible to procure good passage for air and at the same time procure for the element to be manufactured a rather smooth mould outside whieh will result in the element obtaining an even surfaee.
The mould strength neeessary for the earrying through of a production proeess may be aehieved in a simple way by mixing the mould partieles with suitable binding agents whieh may eontain adhesion-improving agents and by hardening the mould manufactured by such mixture by for instanee heat treatment. Also wedging between the partieles may be used to give the mould strength.
Furthermore, according to the invention it is possible to use a mould having at the bottom a basic part in which the eomposite particles are linked together by a real fusion compound whereas the partieles in the rest of the mould are linked together by a hardening eonglutinating eompound. Sueh a mould is eharaeterized by good strength which will also enable it to resist eonsiderable working pressure.
It is also within the scope of the invention to use a mould the mould surface of which is shaped with such strength that the mould may be used for the finishing pres-sing of a moulded element. Finishing pressing may not only be used for quick rernoval of water from the pulp layer de-posited on the mould surface, but also to achieve an espe-cially good material density in the deposited, rather thick fibre material layer and thus an especially higil degree of form stability in the final element.
The desired po~osity of the mould may be achieved by an appropriate choice of the size and distribution of the particles of which the permeable mould surface may be com-posed both to obtain favourable conditions for the fixing compound between the particles and for a suitable dimension-ing of the porosity in order to avoid an undesired pressure drop through a building material which is unnecessarily dense.
The above procedure and mould may as mentioned in prac-tice be used for the production of elements of various fibxe-containing suspensions, everything in the presence of the auxillary materials which may be necessary to create connection in the material layer obtained by suction onto the mould.
The removal of an object formed by the depositing of a fluidized fibre raw material on the outline-forming out-side of the mould surface by means of a gaseous working me-dium may in practice take place by the object being affected by compressed air through the air passages of the mould and thus lifted free of the mouldA In practice the object will, however~ usually still be rather soft and it may therefore for the purpose of removing the object from the casting mould be appropriate to use a transfer mould which is adap-ted to interact with the side of the object pointing away from the mentioned outline-forming outside for the removal 3~ of the object from this outside and for the subsequent.plac-.Z~
ing of the object on for instance a conveyer belt taking theobject to a drying chamber. It is within th~ scope of the invention also to manufacture such a transfer mould from a particle composite material as mentioned above by binding the material particles together for the creation of an open, stable structure with air passages going through to the out-side of the mould and by connecting the thus created mould to a source for a suction provoking vacuum.
The transfer mould is pxoducible directly on the basis of an object pxoduced on the casting mould as on this object a first auxiliary mould (negat.ive) of for instance gypsum is produced corresponding to the side of the object pointing away from the casting mould and on this first auxiliary mould (negative) a second auxiliary mould ~positive) is pro-1~ duced for instance also from gypsum and the transfer mould(negative) is then formed directly on this second auxiliary mould.
The permeable mould surface may be kept clean by, prior to the start of the depositing process or the transfer pro-2~ cess, exposing for cleaning pllrposes the mould surface toan air current passing through the mould passages for a ga-seous medium.
A mould used in accordance with the invention and con-structed by a particle composite material may be manufac-tured in such a way that it may after use or in case of wearbe regenerated as the particle-shaped building material of the mould may be recycled.
For the manufacture of a pulp which is to be easily drained, according to the invention, as fibre raw material at least partly a starting material containing long fibres may be used which is processed to a pulp partly by means of a shake-out in a pulper, partly by a preceding, separate, controlled dry grinding by which the starting material is divided into dosage amounts and divided into-its fibres whereupon the object is manufactured from the pulp thus^ cre-ated.
The use of a pulper as an essential step in the proces-sing of the fibre raw materials for the creation of a pulp from which the desired objects are to be manufactured takes place among other things in cases where the fibre raw mate-rials are received in the form of dry substances in bales, for instance as paper waste.
Heavy whirl formation is produced in the pulper by which the single parts of the material rub against each o-ther and is thereby divided and the raw materials separated into fibres.
Especially in case of heterogeneous material such as 1~ waste or recycled paper it has to be anticipated that this separation is carried out successively so that the fibres released first are exposed to a higher degree of additional substantial processing than the fibres released later. In other words the processing in the pulper will in its pro-ceedings thus be uncontrolled and thus heterogeneous. Thesaid additional processing results in an increase in both the degree of grinding (SR-Schopper-Riegler) and thus the formation of mucus in the pulper, which negatively affects the subsequent draining of the object manu~actured from the pulp and increases the shrinkage of the object during drain-; ing and drying of its material.
The method according to the invention achieves that tothe pulper is at least partly added a fibre raw material the fibres of which are already to a substantial degree se-parated into single fibres why they are more instant and atthe same time susceptible to the self-grinding effect and mixing effect obtained in the pulper. As the pulper proces-ses a more uniform raw material also the grinding degree ob-tained in the pulper through self grinding may be adjusted to be more uniform and the above-mentioned binding of water in the pulp leaving the pulper will thus be more control-lable.
The same procedure will, however, also result in other advantages which are especially valuable in case of recyc-3S ling of paper waste.
Recycled paper waste exists in many different qualitiesand gradings. If ehis material prior to the shake-out in the .. . .
pulper is exposed to a separate, controlled d~y grinding, it is often possible to use a poorer ancl thus cheaper mate~
rial quality, than if the division process was only carried out as a shake-out in the pulper.
It lies within the scope of the invention to carry out the preceding separate dry grinding as mentioned above as a multiple-stage process whereby it is possible to separate the starting material in dosage amounts in a special effi-cient manner.
In this particular way also e.g. waste paper material containing plastic, water resistant paper, plastic laminated cartons and paper, to the degree desired can be separated into fibres and other particles. Separated constituents not beirng paper can be screened off before entering the pulper, or it is possible to let these constituents since they exist in pulveri~ed form enter into the following production pro-cess.
At a performance of the method a long fibre starting material having been subjected to a separate controlled dry grinding be added to an already in the pulper formed pulp and be subjected to a joint time-limited shake-out with this.
In this manner an object can be manufactured whose fibre material is partly mainly bound by hydrogen fibre bin-dings partly have been mixed with air suspended ~ibre mate-rial ~or whose binding glue is normally used. It has turned out that in this way it is possihle to abandon a traditional complete hydrogen binding of the whole pulp, which ~leans that the drain and thereby the production time for the ob-ject can be substantially reduced. Furthermore the methodmakes it possible to obtain a strict contro of the desired object strength characteristics as it will be poisible to have strict control of these by the addition o~ glue.
These advantages are o~ major importance for a rational and thus economic industrial manufacture also of large, form stable objects by the application of the suction techni~ue described.
It will e.g. be possible to carry out a multiple-stage dry grinding by the application of a tearing machine also called a shredder followed by a treatment in a hammer mill which thus can receive the material from the shredder in do-sage amounts and which exposes the material to a furthergrinding process before it if required also in special do sage amounts it added to the pulper for the actual shake-out processing.
The separate, controlled dry grinding suggested accord-ing to the invention of the fibre raw materials prior totheir shake-out in the pulper also provides the possibility for the co-application of recycling waste paper in cases where the objects to be manufactured must be shrink proof and measure proof. A starting material with a high content of wooden fibre causes less shrinkage that if the fibre were cellulose fibre. It has turne~ out that by applying the me-thod according to the invention it is even possible to add to a wooden paper raw material a substantial amount of cheap recycling paper including carton waste which not necessarily is wooden since it is possible to manufacture due to the preceding separate controlled dry grinding of the raw mate-rial a pulp which causes no undesired shrinkage of the ob-jects manufactured.
~ It is a well know principle or the manufacture of ob-; 25 jects of a fluidized fibre raw material to utilize auxiliary materials such as filling material and chemicals and binding agents. The au~iliary materials decide whether the objects manufactured shall be more or less strong, hard or transpa-rent, or weak, soft and absorbing. The present invention is also advantageous in connection with the application of such auxiliary materials.
The division of the manufacturing process in multiple-stages actually increases the possibility of adding the auxiliary materials at different stages of the total manu-facturing process. The achieved open structure o~ the ~inalpulp, obtained as a result of this particular invention, even facilitates a better access for auxiliary materials so that e.g. a binding material may be applied more or less in-tegrating on the surface of the objects in order to increase the weight. The addition o~ auxiliary material under the preceding separate, controlled dry grinding will in a espe-cially good manner be able to further a particular uniformdistribution of the auxiliary materials in the manufactured fibre mass. It is of course also still possible to add the auxiliary materials to the pulper.
Furthermore, it lies within the scope of the invention that the shake-out in the pulper is carried out as a manu-facturing process dependent on the preceding separate, con-trolled grinding. In other words the obtained degree of self grinding in the pulper can be adjusted in accordance with the degree of the grinding which according to the circum-stances has been carried out at the preceding dry grind ngstage(s). As an example~ a paper pulp which in the pulper is separate~ into a normal, at self grinding obtaine~ grin-ding degree of 60 SR (Schopper-Riegler), be added dry grounded fibre material whereafter the mixture is processed in the pulper for 5 minutes more. Objects manufactured from such a mixture pulp may be provided with a special heavy thickness, porosity and permeability. This means that the ~roducts can have good drain qualities and therefore also can be manufactured with large wall thicknesses.
An easily drainable pulp manufactured according to the invention facilitates unproblematically a uniform addition of the fibre suspension over the mould even in cases of ma-nufacturing objects with large wall thickness.
Waste paper, also called return paper, may be very com-posite, and contain fibre with a large variety of fibre lengths. However, it has actually tuxned out that the ave-rage fibre length is so large that the above mentioned ad-vantages especially as regards drainage and structure may be obtained when this paper material forms part of the ma-nufacturing process.
The method according to the invention will also be a-vailable for the processing o~ so-called virgin material.
In the following the invention will be explained in de-2~
taii with reference to the drawing in which Fig. 1 diagrammatically shows a survey of process pro-ceedings summing up the proceeding phases which may take place during the proceeding of a process for the manufacture of for instance a pallet, Fig. 2 examples of combinations of various phases of process proceedings, Fig. 3 an inclined presentation of a first embodiment for a load-carrying element in the form of a pallet manufac-tured by means of the process according to the invention and showing one of the corner parts of the pallet from which the actual corner section is separated, Fig. 4 schematic from the side another embodiment for a pallet, Fig. 5 viewed from the side (Fig. 5b) and sectionally along the line V-V (Fig. 5a) a third embodiment for a pal-let, Fig. 6 schematic cross section through a fourth embo-diment for a pallet, Fig. 7 inclined presentation of a fifth embodiment for a pallet, Fig. 8 schematic cross section through a sixth embo-diment for a pallet, Fig. 9 schematic pallet with a tension rope, Fig. 10 schematic pallet with a wooden support rail, Fog. 11 schematic pallet with a support rail of fibre raw material, Fig. 12 schematic cross section through a pallet con-structed from elements of varying layer thickness, Fig. 13 another embodiment for such pallet Fig. 14 a third embodiment for a pallet containing a single element of varying layer thickness, Fig. 15 a cross section through an embodiment for the supporting legs of a pallet, and Fig. 16 schematic a mould with deposited element of fibre raw material, bo~h the mould surface and thus also the , , deposited element having varying layer thickness.
The diagram of proceedings shown in Figs. 1 and 2 com-prises a total of fourteen process phases. The production process will, according to the production process, be able to be carried out by the use of all these phases, or only some of the phases, but it may also be a question of using some of the phases and then concurrently introducing the re-sulting pxoduct as a supplement to a coherent production process.
Example 1 ~ll 14 process phases are used.
Example 2 Phase 1 up to and including phase 5 is carried out fol-lowed by phases 8 and 9 and finally phases 11 to 1~ are car-ried out.
Example 3 One production line is used from phase 1 to phase ~ and another production line for phase ~ and possibly phases 5, 6 and 7. ~he wet fibre pulp created in the second production line is added to the product resulting from the flrst pro-duction line. The work is continued with usually several of the subsequent phases.
In this way a product is produced in which the fibre material manufactuLed in the second production line is main-ly bound by hydrogen fibre bindings whereas the first pro-duction line produces a fibre material suspended in air and to the binding of which glue is normally used. In this way it is possible to achieve a total degree of grinding, which ls optimum, and simultaneously an optimum addition of glue.
This means that this embodiment for the process allows com-prehensive coTlsideration of the quality of the available raw material.
In the following some embodiments for pallets will be described. The pallets are manufactured by means of the pro-cess according to the invention.
As shown in proceeding diagram in Figs. 1 and 2 the pallets are manufactured from a suspension of a fluidized fibre raw material as the suspension is in an aqueous phase deposited by suction on a contour-shaping foundation. As de-scribed above an easily drainable pulp is created from thefluidized fibre raw material. This pulp is deposited on the contour-shaping foundation in such quantity, and the nega~
tive suction pressure used for depositing of the pulp on the foundation is controlled in such a way that a fibre raw ma-terial layer is deposited on the foundation in such thick-ness that this in all essentials achieves the load capabi-lity desired for the element, i.e. in the present case the pallets.
The water content of the applied pulp may be up to 75 p.c. and this water content may then be removed by pressing and/or drying. As the load capacity of the end product, ~he pallets, is substantially to depend on the thickness of the fibre raw material layer deposited on the contour-shaping foundation, it is an essential prerequisite of a economical production that the employed pulp is easily drainable. The invention comprises a procedure for the production of a pulp with this property.
The end product may then be used as it is or it may to~
gether with similar products form part of another end pro-duct, for instance in the form of a laminate construction.
Experience has shown that it is possible in this wayto manufacture pallets with a low net weight of 5 to 8 kg for a pallet size of 800 x 1200 mm and with a carrying ca-pacity of approx. 500 kg. The carrying capacity will depend on the ~uality of the employed fibre suspension and of the actual pallet's structural design of which some examples will be given in the following.
Fig. 3 shows schematically part of a pallet 10 designed with integrated legs and with strengthening ribs~
~ E~ measurements 800 x 1200 x 120, shaped.three dimensionally in a single working process with "wet" weight 18 kg and weight after drying 6 kg.
~?~
Example b): measurements 800 x 1200 x 120, shaped three dimensionally with "wet" weight 113 kg, weight after heat pressing 12 kg and weight after drying 6 kg.
Fig. 4 shows schematically a pallet in th~ form of a laminate as the pallet has a kottom part 16, which substan-tially corresponds to part 10 in Fig. 3, and an upper, even cover plate 18, which is also designed in accordance with the procedure according to the invention.
Example c): measurements 800 x 1200 x 123, part 16 of the pallet is shaped three dimensionally with "wet" weight 12 kg and weight aft~r drying 4 kg. The cover plate 18 is manufactured on an even moulding surface: "wet" weight 6 kg, weight after heat pressing 4 kg, weight after drying 2 kg.
The cover plate 18 is glued to the top side of bottom part 16.
The cover plate 18 may have holes for the reception of the legs from a pallet lying in a pile above.
Fig. 5 shows a pallet of the same type as shown in Fig.
4, however, with the difference that the upper part 20 of the pallet is shaped three dimensionally with strengthening ribs 22 which correspond with the shaped rib parts 24 in the bottom part 16. Measurements 600 x 800 x 140.
Example d): the under side 16 of the pallet is de~igned with "wet" weight 7.5 kg and weight after drying 2.S kg, and the upper part of the pallet is designed with "wet" weight 4.5 kg and weight after drying 1.5 kg.
Fig. 6 shows a pallet, measurements 800 x 1200 x 150.
Example e). The pallet has a three dimensional centre part 26 with "wet" weight 6 kg and weight after drying 2 kg as well as two cover plates 28 each shaped on an even mould-ing surface and with "wet" weight 6 kg, weight after heat pres.slng 4 kg and weight after drying 2 kg. Furthermore, the p:late has nine three dimensional legs 30 with "wet" weight o each 0.3 kg and weight after drying 0.1 kg. Glue for as-sembling of cover plates and legs 0~05 kg. Finished productweight: 6.95 kg.
Fig. 7 shows a pallet, measurements 800 x 1200 x 150.
J.
Example f): The pallet is composed of two uniform, three dimensional plate elements 32 each having hollow pro-jections 34 projecting transversely to the plate partO The plate elements are mounted with their projections 34 point-ing towards and lying against each other.
Each plate element 32's "wet" weight is 9 kg, weight after drying is 3 kg~ each has nine 100 mm tall legs, "wet"
weight of each 0.3 kg and weight after dxying 0.1 kg. Glue for assembling 0.05 kg. Weight of the finished product: 6.95 kg.
Fig. 8 shows a pallet containing to trapeze profiled centre plates 36, whose ribs 38 cross, and two ou~side~ even cover plates 40. Legs, which are not shown, are glued to one side of these plates.
Both the trapeze shaped and the even plates 36 and ~0, respectively, may be manufactured either by the piece b~
discontinuous moulding or continuously on continuous belt followed by respectively even or trapeze profiled male and female stamping rollers. This results in a high degree of flexibility for the production of the pallet as it is pos-sible to choose a larger og smaller number of plate layers which furthermore, owing to the pressing process, only re-sults in low drying costs.
Example ~: Two trapeze profiled fillers 36 with "wet"
weight after moulding 4.5 kg, "wet" weight after pressing 3.0 kg and weight after drying 1.5 kg. Two even cover plates 40 with "wet" weight after moulding 4.5 kg, "wet" weight af-ter pressing 3.0 kg and weight after drying 1.5 kg. Nine legs (not shown) each with "wet" weight after moulding 0.3 kg and weight after drying 0.1 kg. Glue for assembling 0.05 kg.
In the stated embodiments the plate parts and legs of the pallets may be shaped together in a joint suction opera-tion or they may be shaped in separate suctior. operati4ns.
The legs may also, where desired, be manu~actured ~rom an-other material than fibre raw material but experience has shown that by using the procedure according to the invention it is possible to manufacture legs with sufficient load capacity and robustness and at the same time low weight, as stated in the examples.
Furthermore, the process according to the invention makes it possible without problems to add to the fibre pulp special xeinforcement fibres where an especially high degree of strength is desired.
In the design of the elements it is also possible to consider the placing of additional, outside straining a-gents. Figs. 9 to 11 show some examples of load-carrying e-lements in the form of pallets as a common support rail 44 of for example wood is placed, as for instance shown in Fig.
10, under the legs of the pallet, or as shown in Fig. 11 the use of a special pallet frame 50 composed by legs 46 and a common support rail 48 and manufactuxed from the same mate-rial as the pallet's plate part 52.
As already mentioned the invention's characteristic de-positing of a fibre raw material layer of such thickness that this essentially produces the load capability desired for the element renders the opportunity of exploi~ing the la~er thickness for an additional increase in the load ca-pability in the way that in the fibre raw material layer va-riations are made in the layer thickness, for 1nstance as a coherent structural pattern. This means that by means of ~S variations in the layer thickness, for instance rib-like ~ormations are created in which the layer thickness of the elements is thicker than in the other areas of the element.
I the forming and arrangement of such or similar formations are suitable, an increased rigidity may be achieved in the element whereby its load capacity is increased.
Figs. 12 to 15 show examples of such variations. As also mentioned above such variations are achieved by using a mould which at negative pressure is permeable by a gaseous active working medium which mould has a mould surface, per-meable by the working medium, with a permeability varyingin accordance with the desired variations in the layer thickness of the layer.
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Fig. 12 shows a cross section of a pallet constructed from two rib profiled interior elements 5~ which on the out side are covered by to even cover plates 56. Each interior element 54 has been manufactured in one single working pro-cess from a fibre raw material which is deposited on themould surface of the suction mould with a wall thickness va-rying from rib top to rib bottom the largest wall thickness being at the rib top 54a and the smallest at the rib bottom 54b. The cross section profile of the rib formation is an-gular and the interior elements 54 are lying against eachother at the top 54a.
Fig. 13 shows a cross section of the same type of pal-let with the difference, however, that the interior elements 54 are lying together at the bottom 54b so that the rib tops 54a carry the cover plates 56.
Fig. 14 shows a cross section of a pallet with only one single interior element 58, which with its tops 58a and bot-toms 58b lie against exterior, even cover plates 60. As men-tioned, also this interior e]ement 58 is manufactured in one single working process with such variation in the layer thickness that this is largest at the rib top 58a and smal-lest at the rib bottom 58b.
Fig. 15 shows an examp]e of a supporting leg 62 of a pallet. The leg 62 is pot sha~ed and manufactured in one single active working process through suction of a fibre raw material as described. Also this element has varying layer thickness and it is thicker at the bottom 62b.
Fig. 16 illustrates how such variations in the layer thic~ness may be achieved according to the invention. As schematically illustrated a mould 64 which at negative pres-sure is permeable by a gaseous active working medium is used for suction onto the mould surface of the mould of an easily drained pulp created from fluidized fibre raw ~aterial, which mould has a by the wsrking medium permeable mould sur-face 66. In accordance with the creation of a rib profi~ledpallet element 68 in which the material layer is thick in the rib top 6~a and thin in the rib bottom 68b a mould with c~
a rib profiled mould surface 66 with varying permeability is used, the mould surface 66 being thick at the mould surface tops 64b and thin at the mould surface bottoms 64a.
This results in the suction effect being weaker at the part of the mould surface created by the mould surface tops ~4b than at the part created by the mould surface bottoms 64a.
This will in its turn result in less depositing durlng suc-tion of the added fibre pulp of fibre material at the mould surface tops 64b which form the rib tops 68a whereby the layer thickness of these and consequently the rib formation created by them achieves a rather high degree of thickness and strength. This production technique may in principle be used in connection with many different variations in the layer thickness and the above-mentioned is only meant as a typical example oF this.
The useability of the invention has been illustrated above by examples of pallets. It may with equal advantage be used also for the production of many other kinds of load carrying elements including wall elements for various pur-poses, building elements and insulating elements. Further-more, the above shows that the process according to the in-vention has opened up for suitable employment of many kinds of starting materials and additives. ~he invention also o-pens up the possibility of unproblematic incorporation of foils or reticular objects in the outside of the created ob-ject.
The present invention concerns a method for the manu-facture of load-carrying elements, including pallets by the depositing of a fluidized fibre raw matexial on a moulding foundation by suction of a pulp of the :Eibre raw material on this foundation.
A fluidized fibre raw material means a starting mate-rial, which may be in wet form, of ~ fibrous nature and suited for the manufacture of the deslred objects. Such starting material may for instance be a fibre pulp material as used for instance for trays and cartons for packaging of fragile and sensitive objects such as fruit, flowers, eg~s and objects of for instance glass. The pulp material usually consists of a suspended, fibrous cellulose.
It is well known for this purpose to use a production technique by which the starting material in the form of a pulp is by a depositing process placed against the outline-forming outside of a mould which is permeable to let a ga- ~, seous working medium, through a suction effect, affect the material through the material of the mould and thus mould the contour of the material on the mould through suction.
The object of the invention is to indicate how this in itself suitable production technique may be used not only to manufacture relatively small and light objects but also to manufacture large, rather heavy objects characterized by extremely high load capacity which are substantially based on a corresponding thickness of the material layer deposited on the moulding foundation. In comparison with this the wall thickness of the said small and light objects is rather thin and the rigidity necessary in practice is usually obtained by deliberately forming the wall panels which for instance support the said objects as the walls produce a rather rigid total object by mutually supporting each other.
According to the invention the stated objective is a-chieved by applying to the foundatio~ an easily drainable pulp made of the fluidized fibre raw material in such quan-tity and by controlling the suction in such a way that a fibre raw material layer of such thickness as to provide ~n~
substantially the load capacity desired for the element.
This will by using the above production technique also enable the manufacture of ~lements with high load capacity such as pallets and building elements which may, contrary to the said packaging examples, display rather even and smooth outer surface and which in itself displays a high de-gree of form stability. The depositing of a fibre raw mate-rial layer of the defined thickness means that the negative pressure in the fibre raw material layex used for suction may procure a material density which is highest at the out-side of the material layer directed towards the mould sur-face and which will have a reinforcing effect as it is placed at a distance from the through-going centre plan of the deposited object.
~5 By using the layer thickness of the element thus manu-factured its load capacity may according to the invention also be increased by procuring in the fibre raw material layer and distributed over this one or more variations in the layer thickness by correspondingly locally varying the suction effect during a joint suction process for the fibre pulp volume necessary for the manufacture of the whole ele-ment. In this way it will be possible in one and the same working process, i.e. the depositing of the fibre raw mate-rial on the moulding foundation, to mould both the final outside desired for the element and, by using the thickness of the material layer, a load capacity increasing moulded structure in the actual material object forming the element.
According to the invention such a structure will for in-stance be able to be shaped as a connected structural pat-tern with a thicker layer thickness compared with the partsof the element.
According to the invention a suitable way for the car-rying through of the method is characteristic in that, for suction of an easily drainable pulp of the fibre raw ma~te-rial in the desired thickness, a mould is used which at ne-gative pressure is permeable by a gaseous active working me-dium and which has a by the working medium permeable mould surface the perm~ability of which is adjusted to the thick-ness of the fibre raw material layer to be deposited b~ suc-tion of the pulp on this surface.
In this way it is possible to achieve such interaction between the draining ability of the pulp and the suction capability of the mould surface that also elements having thic~ fibre layer thickness owing to the desired load capa-city may be manufactured rationally.
In order to achieve local variations in the layer thickness of the fibre raw material layer of the element, a mould having a mould surface with a permeability varying in accordance with the layer thickness of the local varia-tion or variations respectively or the coherent structural pattern of the easily drainable fibre pulp layer deposited on the mould surface by suction may be used according to the invention.
This means that the depositing of fibre raw m~terial on the mould surface will vary according to the permeability of this surface which results in local variations in the suction effect which, in areas with poor mould surface per-meability, causes reduced depositing of fibre raw material in th.e mould surface whereas the depositing will be high in areas with high mould surface permeability.
~According to the invention, an embodiment of this me-:25 thod may be characterized by the use for suction of an easily drainable pulp of the fibre raw material in the de-sired thickness of a mould which at negative pressure is permeablQ by a gaseous active working medium which at least as regards the outline-forming part consists of a partial composite material the particles of which are fixed together for the formation of a contour-stable mould surface at the same time as they together limit passages open to the work-ing medium, which passages extend through the composite ma-terial to the outside surface of the mould, and that the thickness of at least the composite material layer forming the mould surface is adjusted according to the thickness of the fibre raw material layer to be deposited by suction of the pulp to this surface.
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Such a mould may be manufactured on the basis of a cheap, inorganic raw material such as sand as well as by means of a produetion teehni~ue which is simple, of short duration and thus also cheap. The total produetion eosts o~
the mould may thus be kept at a low level and this form of construction will consequently be suitable for the produc-tion of a small number of products.
In order to achieve local variations in the layer thickness of the element's fibre raw material layer a mould may, according to the latter procedure, be used in which the composite material formed by the mould surface has a thiek-ness that varies in accordance with the layer thickness of the local variation or variations, respeetively, or the de-sired coherent structural pattern of the easily drainable fibre pulp la~er deposited on the mould surface by suction.
According to the invention a mould may be used the per-meable mould surface of which is composed of partieles with varying particle size, the particle size being small in the part forming the mould surface of the mould and larger in an underlying supporting layer for this part. In this way it is possible to procure good passage for air and at the same time procure for the element to be manufactured a rather smooth mould outside whieh will result in the element obtaining an even surfaee.
The mould strength neeessary for the earrying through of a production proeess may be aehieved in a simple way by mixing the mould partieles with suitable binding agents whieh may eontain adhesion-improving agents and by hardening the mould manufactured by such mixture by for instanee heat treatment. Also wedging between the partieles may be used to give the mould strength.
Furthermore, according to the invention it is possible to use a mould having at the bottom a basic part in which the eomposite particles are linked together by a real fusion compound whereas the partieles in the rest of the mould are linked together by a hardening eonglutinating eompound. Sueh a mould is eharaeterized by good strength which will also enable it to resist eonsiderable working pressure.
It is also within the scope of the invention to use a mould the mould surface of which is shaped with such strength that the mould may be used for the finishing pres-sing of a moulded element. Finishing pressing may not only be used for quick rernoval of water from the pulp layer de-posited on the mould surface, but also to achieve an espe-cially good material density in the deposited, rather thick fibre material layer and thus an especially higil degree of form stability in the final element.
The desired po~osity of the mould may be achieved by an appropriate choice of the size and distribution of the particles of which the permeable mould surface may be com-posed both to obtain favourable conditions for the fixing compound between the particles and for a suitable dimension-ing of the porosity in order to avoid an undesired pressure drop through a building material which is unnecessarily dense.
The above procedure and mould may as mentioned in prac-tice be used for the production of elements of various fibxe-containing suspensions, everything in the presence of the auxillary materials which may be necessary to create connection in the material layer obtained by suction onto the mould.
The removal of an object formed by the depositing of a fluidized fibre raw material on the outline-forming out-side of the mould surface by means of a gaseous working me-dium may in practice take place by the object being affected by compressed air through the air passages of the mould and thus lifted free of the mouldA In practice the object will, however~ usually still be rather soft and it may therefore for the purpose of removing the object from the casting mould be appropriate to use a transfer mould which is adap-ted to interact with the side of the object pointing away from the mentioned outline-forming outside for the removal 3~ of the object from this outside and for the subsequent.plac-.Z~
ing of the object on for instance a conveyer belt taking theobject to a drying chamber. It is within th~ scope of the invention also to manufacture such a transfer mould from a particle composite material as mentioned above by binding the material particles together for the creation of an open, stable structure with air passages going through to the out-side of the mould and by connecting the thus created mould to a source for a suction provoking vacuum.
The transfer mould is pxoducible directly on the basis of an object pxoduced on the casting mould as on this object a first auxiliary mould (negat.ive) of for instance gypsum is produced corresponding to the side of the object pointing away from the casting mould and on this first auxiliary mould (negative) a second auxiliary mould ~positive) is pro-1~ duced for instance also from gypsum and the transfer mould(negative) is then formed directly on this second auxiliary mould.
The permeable mould surface may be kept clean by, prior to the start of the depositing process or the transfer pro-2~ cess, exposing for cleaning pllrposes the mould surface toan air current passing through the mould passages for a ga-seous medium.
A mould used in accordance with the invention and con-structed by a particle composite material may be manufac-tured in such a way that it may after use or in case of wearbe regenerated as the particle-shaped building material of the mould may be recycled.
For the manufacture of a pulp which is to be easily drained, according to the invention, as fibre raw material at least partly a starting material containing long fibres may be used which is processed to a pulp partly by means of a shake-out in a pulper, partly by a preceding, separate, controlled dry grinding by which the starting material is divided into dosage amounts and divided into-its fibres whereupon the object is manufactured from the pulp thus^ cre-ated.
The use of a pulper as an essential step in the proces-sing of the fibre raw materials for the creation of a pulp from which the desired objects are to be manufactured takes place among other things in cases where the fibre raw mate-rials are received in the form of dry substances in bales, for instance as paper waste.
Heavy whirl formation is produced in the pulper by which the single parts of the material rub against each o-ther and is thereby divided and the raw materials separated into fibres.
Especially in case of heterogeneous material such as 1~ waste or recycled paper it has to be anticipated that this separation is carried out successively so that the fibres released first are exposed to a higher degree of additional substantial processing than the fibres released later. In other words the processing in the pulper will in its pro-ceedings thus be uncontrolled and thus heterogeneous. Thesaid additional processing results in an increase in both the degree of grinding (SR-Schopper-Riegler) and thus the formation of mucus in the pulper, which negatively affects the subsequent draining of the object manu~actured from the pulp and increases the shrinkage of the object during drain-; ing and drying of its material.
The method according to the invention achieves that tothe pulper is at least partly added a fibre raw material the fibres of which are already to a substantial degree se-parated into single fibres why they are more instant and atthe same time susceptible to the self-grinding effect and mixing effect obtained in the pulper. As the pulper proces-ses a more uniform raw material also the grinding degree ob-tained in the pulper through self grinding may be adjusted to be more uniform and the above-mentioned binding of water in the pulp leaving the pulper will thus be more control-lable.
The same procedure will, however, also result in other advantages which are especially valuable in case of recyc-3S ling of paper waste.
Recycled paper waste exists in many different qualitiesand gradings. If ehis material prior to the shake-out in the .. . .
pulper is exposed to a separate, controlled d~y grinding, it is often possible to use a poorer ancl thus cheaper mate~
rial quality, than if the division process was only carried out as a shake-out in the pulper.
It lies within the scope of the invention to carry out the preceding separate dry grinding as mentioned above as a multiple-stage process whereby it is possible to separate the starting material in dosage amounts in a special effi-cient manner.
In this particular way also e.g. waste paper material containing plastic, water resistant paper, plastic laminated cartons and paper, to the degree desired can be separated into fibres and other particles. Separated constituents not beirng paper can be screened off before entering the pulper, or it is possible to let these constituents since they exist in pulveri~ed form enter into the following production pro-cess.
At a performance of the method a long fibre starting material having been subjected to a separate controlled dry grinding be added to an already in the pulper formed pulp and be subjected to a joint time-limited shake-out with this.
In this manner an object can be manufactured whose fibre material is partly mainly bound by hydrogen fibre bin-dings partly have been mixed with air suspended ~ibre mate-rial ~or whose binding glue is normally used. It has turned out that in this way it is possihle to abandon a traditional complete hydrogen binding of the whole pulp, which ~leans that the drain and thereby the production time for the ob-ject can be substantially reduced. Furthermore the methodmakes it possible to obtain a strict contro of the desired object strength characteristics as it will be poisible to have strict control of these by the addition o~ glue.
These advantages are o~ major importance for a rational and thus economic industrial manufacture also of large, form stable objects by the application of the suction techni~ue described.
It will e.g. be possible to carry out a multiple-stage dry grinding by the application of a tearing machine also called a shredder followed by a treatment in a hammer mill which thus can receive the material from the shredder in do-sage amounts and which exposes the material to a furthergrinding process before it if required also in special do sage amounts it added to the pulper for the actual shake-out processing.
The separate, controlled dry grinding suggested accord-ing to the invention of the fibre raw materials prior totheir shake-out in the pulper also provides the possibility for the co-application of recycling waste paper in cases where the objects to be manufactured must be shrink proof and measure proof. A starting material with a high content of wooden fibre causes less shrinkage that if the fibre were cellulose fibre. It has turne~ out that by applying the me-thod according to the invention it is even possible to add to a wooden paper raw material a substantial amount of cheap recycling paper including carton waste which not necessarily is wooden since it is possible to manufacture due to the preceding separate controlled dry grinding of the raw mate-rial a pulp which causes no undesired shrinkage of the ob-jects manufactured.
~ It is a well know principle or the manufacture of ob-; 25 jects of a fluidized fibre raw material to utilize auxiliary materials such as filling material and chemicals and binding agents. The au~iliary materials decide whether the objects manufactured shall be more or less strong, hard or transpa-rent, or weak, soft and absorbing. The present invention is also advantageous in connection with the application of such auxiliary materials.
The division of the manufacturing process in multiple-stages actually increases the possibility of adding the auxiliary materials at different stages of the total manu-facturing process. The achieved open structure o~ the ~inalpulp, obtained as a result of this particular invention, even facilitates a better access for auxiliary materials so that e.g. a binding material may be applied more or less in-tegrating on the surface of the objects in order to increase the weight. The addition o~ auxiliary material under the preceding separate, controlled dry grinding will in a espe-cially good manner be able to further a particular uniformdistribution of the auxiliary materials in the manufactured fibre mass. It is of course also still possible to add the auxiliary materials to the pulper.
Furthermore, it lies within the scope of the invention that the shake-out in the pulper is carried out as a manu-facturing process dependent on the preceding separate, con-trolled grinding. In other words the obtained degree of self grinding in the pulper can be adjusted in accordance with the degree of the grinding which according to the circum-stances has been carried out at the preceding dry grind ngstage(s). As an example~ a paper pulp which in the pulper is separate~ into a normal, at self grinding obtaine~ grin-ding degree of 60 SR (Schopper-Riegler), be added dry grounded fibre material whereafter the mixture is processed in the pulper for 5 minutes more. Objects manufactured from such a mixture pulp may be provided with a special heavy thickness, porosity and permeability. This means that the ~roducts can have good drain qualities and therefore also can be manufactured with large wall thicknesses.
An easily drainable pulp manufactured according to the invention facilitates unproblematically a uniform addition of the fibre suspension over the mould even in cases of ma-nufacturing objects with large wall thickness.
Waste paper, also called return paper, may be very com-posite, and contain fibre with a large variety of fibre lengths. However, it has actually tuxned out that the ave-rage fibre length is so large that the above mentioned ad-vantages especially as regards drainage and structure may be obtained when this paper material forms part of the ma-nufacturing process.
The method according to the invention will also be a-vailable for the processing o~ so-called virgin material.
In the following the invention will be explained in de-2~
taii with reference to the drawing in which Fig. 1 diagrammatically shows a survey of process pro-ceedings summing up the proceeding phases which may take place during the proceeding of a process for the manufacture of for instance a pallet, Fig. 2 examples of combinations of various phases of process proceedings, Fig. 3 an inclined presentation of a first embodiment for a load-carrying element in the form of a pallet manufac-tured by means of the process according to the invention and showing one of the corner parts of the pallet from which the actual corner section is separated, Fig. 4 schematic from the side another embodiment for a pallet, Fig. 5 viewed from the side (Fig. 5b) and sectionally along the line V-V (Fig. 5a) a third embodiment for a pal-let, Fig. 6 schematic cross section through a fourth embo-diment for a pallet, Fig. 7 inclined presentation of a fifth embodiment for a pallet, Fig. 8 schematic cross section through a sixth embo-diment for a pallet, Fig. 9 schematic pallet with a tension rope, Fig. 10 schematic pallet with a wooden support rail, Fog. 11 schematic pallet with a support rail of fibre raw material, Fig. 12 schematic cross section through a pallet con-structed from elements of varying layer thickness, Fig. 13 another embodiment for such pallet Fig. 14 a third embodiment for a pallet containing a single element of varying layer thickness, Fig. 15 a cross section through an embodiment for the supporting legs of a pallet, and Fig. 16 schematic a mould with deposited element of fibre raw material, bo~h the mould surface and thus also the , , deposited element having varying layer thickness.
The diagram of proceedings shown in Figs. 1 and 2 com-prises a total of fourteen process phases. The production process will, according to the production process, be able to be carried out by the use of all these phases, or only some of the phases, but it may also be a question of using some of the phases and then concurrently introducing the re-sulting pxoduct as a supplement to a coherent production process.
Example 1 ~ll 14 process phases are used.
Example 2 Phase 1 up to and including phase 5 is carried out fol-lowed by phases 8 and 9 and finally phases 11 to 1~ are car-ried out.
Example 3 One production line is used from phase 1 to phase ~ and another production line for phase ~ and possibly phases 5, 6 and 7. ~he wet fibre pulp created in the second production line is added to the product resulting from the flrst pro-duction line. The work is continued with usually several of the subsequent phases.
In this way a product is produced in which the fibre material manufactuLed in the second production line is main-ly bound by hydrogen fibre bindings whereas the first pro-duction line produces a fibre material suspended in air and to the binding of which glue is normally used. In this way it is possible to achieve a total degree of grinding, which ls optimum, and simultaneously an optimum addition of glue.
This means that this embodiment for the process allows com-prehensive coTlsideration of the quality of the available raw material.
In the following some embodiments for pallets will be described. The pallets are manufactured by means of the pro-cess according to the invention.
As shown in proceeding diagram in Figs. 1 and 2 the pallets are manufactured from a suspension of a fluidized fibre raw material as the suspension is in an aqueous phase deposited by suction on a contour-shaping foundation. As de-scribed above an easily drainable pulp is created from thefluidized fibre raw material. This pulp is deposited on the contour-shaping foundation in such quantity, and the nega~
tive suction pressure used for depositing of the pulp on the foundation is controlled in such a way that a fibre raw ma-terial layer is deposited on the foundation in such thick-ness that this in all essentials achieves the load capabi-lity desired for the element, i.e. in the present case the pallets.
The water content of the applied pulp may be up to 75 p.c. and this water content may then be removed by pressing and/or drying. As the load capacity of the end product, ~he pallets, is substantially to depend on the thickness of the fibre raw material layer deposited on the contour-shaping foundation, it is an essential prerequisite of a economical production that the employed pulp is easily drainable. The invention comprises a procedure for the production of a pulp with this property.
The end product may then be used as it is or it may to~
gether with similar products form part of another end pro-duct, for instance in the form of a laminate construction.
Experience has shown that it is possible in this wayto manufacture pallets with a low net weight of 5 to 8 kg for a pallet size of 800 x 1200 mm and with a carrying ca-pacity of approx. 500 kg. The carrying capacity will depend on the ~uality of the employed fibre suspension and of the actual pallet's structural design of which some examples will be given in the following.
Fig. 3 shows schematically part of a pallet 10 designed with integrated legs and with strengthening ribs~
~ E~ measurements 800 x 1200 x 120, shaped.three dimensionally in a single working process with "wet" weight 18 kg and weight after drying 6 kg.
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Example b): measurements 800 x 1200 x 120, shaped three dimensionally with "wet" weight 113 kg, weight after heat pressing 12 kg and weight after drying 6 kg.
Fig. 4 shows schematically a pallet in th~ form of a laminate as the pallet has a kottom part 16, which substan-tially corresponds to part 10 in Fig. 3, and an upper, even cover plate 18, which is also designed in accordance with the procedure according to the invention.
Example c): measurements 800 x 1200 x 123, part 16 of the pallet is shaped three dimensionally with "wet" weight 12 kg and weight aft~r drying 4 kg. The cover plate 18 is manufactured on an even moulding surface: "wet" weight 6 kg, weight after heat pressing 4 kg, weight after drying 2 kg.
The cover plate 18 is glued to the top side of bottom part 16.
The cover plate 18 may have holes for the reception of the legs from a pallet lying in a pile above.
Fig. 5 shows a pallet of the same type as shown in Fig.
4, however, with the difference that the upper part 20 of the pallet is shaped three dimensionally with strengthening ribs 22 which correspond with the shaped rib parts 24 in the bottom part 16. Measurements 600 x 800 x 140.
Example d): the under side 16 of the pallet is de~igned with "wet" weight 7.5 kg and weight after drying 2.S kg, and the upper part of the pallet is designed with "wet" weight 4.5 kg and weight after drying 1.5 kg.
Fig. 6 shows a pallet, measurements 800 x 1200 x 150.
Example e). The pallet has a three dimensional centre part 26 with "wet" weight 6 kg and weight after drying 2 kg as well as two cover plates 28 each shaped on an even mould-ing surface and with "wet" weight 6 kg, weight after heat pres.slng 4 kg and weight after drying 2 kg. Furthermore, the p:late has nine three dimensional legs 30 with "wet" weight o each 0.3 kg and weight after drying 0.1 kg. Glue for as-sembling of cover plates and legs 0~05 kg. Finished productweight: 6.95 kg.
Fig. 7 shows a pallet, measurements 800 x 1200 x 150.
J.
Example f): The pallet is composed of two uniform, three dimensional plate elements 32 each having hollow pro-jections 34 projecting transversely to the plate partO The plate elements are mounted with their projections 34 point-ing towards and lying against each other.
Each plate element 32's "wet" weight is 9 kg, weight after drying is 3 kg~ each has nine 100 mm tall legs, "wet"
weight of each 0.3 kg and weight after dxying 0.1 kg. Glue for assembling 0.05 kg. Weight of the finished product: 6.95 kg.
Fig. 8 shows a pallet containing to trapeze profiled centre plates 36, whose ribs 38 cross, and two ou~side~ even cover plates 40. Legs, which are not shown, are glued to one side of these plates.
Both the trapeze shaped and the even plates 36 and ~0, respectively, may be manufactured either by the piece b~
discontinuous moulding or continuously on continuous belt followed by respectively even or trapeze profiled male and female stamping rollers. This results in a high degree of flexibility for the production of the pallet as it is pos-sible to choose a larger og smaller number of plate layers which furthermore, owing to the pressing process, only re-sults in low drying costs.
Example ~: Two trapeze profiled fillers 36 with "wet"
weight after moulding 4.5 kg, "wet" weight after pressing 3.0 kg and weight after drying 1.5 kg. Two even cover plates 40 with "wet" weight after moulding 4.5 kg, "wet" weight af-ter pressing 3.0 kg and weight after drying 1.5 kg. Nine legs (not shown) each with "wet" weight after moulding 0.3 kg and weight after drying 0.1 kg. Glue for assembling 0.05 kg.
In the stated embodiments the plate parts and legs of the pallets may be shaped together in a joint suction opera-tion or they may be shaped in separate suctior. operati4ns.
The legs may also, where desired, be manu~actured ~rom an-other material than fibre raw material but experience has shown that by using the procedure according to the invention it is possible to manufacture legs with sufficient load capacity and robustness and at the same time low weight, as stated in the examples.
Furthermore, the process according to the invention makes it possible without problems to add to the fibre pulp special xeinforcement fibres where an especially high degree of strength is desired.
In the design of the elements it is also possible to consider the placing of additional, outside straining a-gents. Figs. 9 to 11 show some examples of load-carrying e-lements in the form of pallets as a common support rail 44 of for example wood is placed, as for instance shown in Fig.
10, under the legs of the pallet, or as shown in Fig. 11 the use of a special pallet frame 50 composed by legs 46 and a common support rail 48 and manufactuxed from the same mate-rial as the pallet's plate part 52.
As already mentioned the invention's characteristic de-positing of a fibre raw material layer of such thickness that this essentially produces the load capability desired for the element renders the opportunity of exploi~ing the la~er thickness for an additional increase in the load ca-pability in the way that in the fibre raw material layer va-riations are made in the layer thickness, for 1nstance as a coherent structural pattern. This means that by means of ~S variations in the layer thickness, for instance rib-like ~ormations are created in which the layer thickness of the elements is thicker than in the other areas of the element.
I the forming and arrangement of such or similar formations are suitable, an increased rigidity may be achieved in the element whereby its load capacity is increased.
Figs. 12 to 15 show examples of such variations. As also mentioned above such variations are achieved by using a mould which at negative pressure is permeable by a gaseous active working medium which mould has a mould surface, per-meable by the working medium, with a permeability varyingin accordance with the desired variations in the layer thickness of the layer.
~nn~
Fig. 12 shows a cross section of a pallet constructed from two rib profiled interior elements 5~ which on the out side are covered by to even cover plates 56. Each interior element 54 has been manufactured in one single working pro-cess from a fibre raw material which is deposited on themould surface of the suction mould with a wall thickness va-rying from rib top to rib bottom the largest wall thickness being at the rib top 54a and the smallest at the rib bottom 54b. The cross section profile of the rib formation is an-gular and the interior elements 54 are lying against eachother at the top 54a.
Fig. 13 shows a cross section of the same type of pal-let with the difference, however, that the interior elements 54 are lying together at the bottom 54b so that the rib tops 54a carry the cover plates 56.
Fig. 14 shows a cross section of a pallet with only one single interior element 58, which with its tops 58a and bot-toms 58b lie against exterior, even cover plates 60. As men-tioned, also this interior e]ement 58 is manufactured in one single working process with such variation in the layer thickness that this is largest at the rib top 58a and smal-lest at the rib bottom 58b.
Fig. 15 shows an examp]e of a supporting leg 62 of a pallet. The leg 62 is pot sha~ed and manufactured in one single active working process through suction of a fibre raw material as described. Also this element has varying layer thickness and it is thicker at the bottom 62b.
Fig. 16 illustrates how such variations in the layer thic~ness may be achieved according to the invention. As schematically illustrated a mould 64 which at negative pres-sure is permeable by a gaseous active working medium is used for suction onto the mould surface of the mould of an easily drained pulp created from fluidized fibre raw ~aterial, which mould has a by the wsrking medium permeable mould sur-face 66. In accordance with the creation of a rib profi~ledpallet element 68 in which the material layer is thick in the rib top 6~a and thin in the rib bottom 68b a mould with c~
a rib profiled mould surface 66 with varying permeability is used, the mould surface 66 being thick at the mould surface tops 64b and thin at the mould surface bottoms 64a.
This results in the suction effect being weaker at the part of the mould surface created by the mould surface tops ~4b than at the part created by the mould surface bottoms 64a.
This will in its turn result in less depositing durlng suc-tion of the added fibre pulp of fibre material at the mould surface tops 64b which form the rib tops 68a whereby the layer thickness of these and consequently the rib formation created by them achieves a rather high degree of thickness and strength. This production technique may in principle be used in connection with many different variations in the layer thickness and the above-mentioned is only meant as a typical example oF this.
The useability of the invention has been illustrated above by examples of pallets. It may with equal advantage be used also for the production of many other kinds of load carrying elements including wall elements for various pur-poses, building elements and insulating elements. Further-more, the above shows that the process according to the in-vention has opened up for suitable employment of many kinds of starting materials and additives. ~he invention also o-pens up the possibility of unproblematic incorporation of foils or reticular objects in the outside of the created ob-ject.
Claims (24)
1. Method for the manufacture of load carrying ele-ments, including pallets, by depositing of a fluidized fibre raw material on a form giving foundation by means of suction of a pulp of fibre raw material on this foundation characte-rized by the application to the foundation of an easily drainable pulp made of the fluidized fibre raw material in such amounts, and that the suction is carried out and con-trolled in such a way that on the foundation by suction is deposited a fibre raw material layer with such wall thick-ness that this in all essentials procures the desired load capacity of the object.
2. Method in accordance with claim 1 characterized by, distributed over the fibre raw material layer, one or more variations in the wall thickness are procured in the said layer through the suction effect being correspondingly va-ried locally in a common suction process for the fibre pulp quantity necessary for the manufacture of the whole ele-ment.
3. Procedure in accordance with claim 2 characterized in that the depositing of the fibre raw material with a thickness corresponding to the desired load capacity is pro-cured as a coherent structured pattern with a larger wall thickness in comparison with the other areas.
4. Method in accordance with any of the claims 1-3, characterized by the fact that for suction of an easily drainable pulp of the fibre raw material in the desired wall thickness, a mould is used which at negative pressure is permeable by a gaseous active working medium, and which has a by a working medium permeable mould surface the permeabi-lity of which is adjusted to the thickness of the fibre raw material layer to be deposited by suction of the pulp on this surface.
5. Method in accordance with claim 4, for the carrying out of procedure in accordance with claims 2 or 3, characte-rized by the fact that a mould is used whose mould surface has a permeability which varies in accordance with the wall thickness of the local variation(s); respectively, or the desired coherent structured pattern of the by the suction on the form surface deposited easily drained fibre pulp layer.
6. Method in accordance with claim 4, characterized by the fact that for suction of an easily drainable pulp of the fibre raw material in the desired wall thickness, a mould is used which at negative pressure is permeable by a gaseous active working medium, and which at least for the contour giving part of the mould is manufactured by a particle com-posite material whose particles are fixed together for the creation of a contour stable mould surface and at the same time restricting open passages for the working medium ex-tending through the composite material to the mould outside surface and that the thickness in at least of the composite material layer forming the mould surface is adjusted to the thickness of the fibre raw material layer which is to be de-posited through suction of the pulp on this surface.
7. Method in accordance with claim 5, characterized by the fact that a mould is used by means of which the layer of composite material forming the mould surface is manufac-tured with a thickness varying in accordance with the wall thickness of the local variation(s), respectively, or the desired coherent structured pattern of the through suction on the mould surface deposited, easily drainable fibre pulp layer.
8. Method in accordance with any of the claims 4 to 7, characterized by the fact that a mould is used whose per-meable mould surface is composed of particles of different particle size, the particle size being small in the mould forming surface part and bigger in a lower supporting layer for this part.
9. Method in accordance with claim 8, characterized by the fact that a mould is used whose particles are clad with a layer formed by a binding agent.
10. Method in accordance with claim 9, characterized by the fact that a mould is used whose binding agent is thermo-setting.
11. Method in accordance with claim 9 characterized by the fact that a mould is used whose binding agent consists of adhesion-improving agent.
12. Method in accordance with claim 8 characterized by the fact that a mould is used by which the particles have a rounded form.
13. Method in accordance with claim 8 characterized by the fact that a mould is used by which the particles are in a wedging compound with each other.
14. Method in accordance with claims 5 or 6 charac-terized by the fact that a mould is used having below a ba-sis part in which the composite particles are connected with each other through a real fusion compound while the par-ticles of the rest of the mould are linked to each other through a hardening conglutination compound.
15. Method in accordance with any of the claims 4-14 characterized by the fact that a mould is used whose mould surface is designed with such a strength that the mould is applicable for finishing pressing of an object.
16. Method in accordance with any of the previous claims characterized by the fact that as fibre raw material at least partly a long fibre starting material is used which is processed into a pulp partly by the application of a shake-out in a pulper, partly by a preceding, separate, con-trolled dry grinding, whereby the starting material is se-parated into dosage amounts and divided into fibre whereaf-ter the object is manufactured from the pulp thus created.
17. Method in accordance with claim 16 characterized by the fact that the preceding separate dry grinding con-trolled manufacturing process is carried out as a multiple-stage process.
18. Method in accordance with claim 16 or 17 characte-rized by the fact that the shake-out is carried out as con-trolled manufacturing process dependent on the separate dry grinding.
19. Method in accordance with any of the claims 16-18 characterized by the fact that a long fibre starting mate-rial having been subjected to a separate, controlled dry grinding is added in dosage amounts to a pulp already cre-ated in the pulper and subjected to a common time-limited shake-out with this.
20. Method in accordance with any of the claims 16-19 characterized by the fact that an addition of auxiliary material is undertaken in connection with the preceding se-parate dry grinding.
21. Method in accordance with any of the claims 16-20 characterized by the fact that an addition of auxiliary material during further application of the created pulp.
22. Method in accordance with any of the claims 16-21 characterized by the fact that a pulp is manufactured as stated in claim 16, and that this pulp in dosage amounts is added another already manufactured pulp whereafter the ob-ject is manufactured from the mixture thus created.
23. Load carrying element consisting of a fluidized fibre raw material characterized by the fact that the ele-ment is manufactured by means of the method in accordance with one or more of the claims 1 to 22.
24. Pallet consisting of a plate part and connected supporting legs characterized by the fact that the pallet is manufactured by means of the method according to one or more of the claims 1 to 22.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DK592388A DK166736B1 (en) | 1988-10-25 | 1988-10-25 | PROCEDURE FOR THE MANUFACTURE OF BEARING ELEMENTS, INCLUDING LOADS FROM A FLUIDIZED CELLULOSE FIBER MATERIAL |
| DK5923/88 | 1988-10-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2001299A1 true CA2001299A1 (en) | 1990-04-25 |
Family
ID=8146187
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2001299 Abandoned CA2001299A1 (en) | 1988-10-25 | 1989-10-24 | Method for the manufacture of load-carrying elements, including pallets |
Country Status (17)
| Country | Link |
|---|---|
| EP (1) | EP0441847A1 (en) |
| JP (1) | JPH04502184A (en) |
| CN (1) | CN1025061C (en) |
| AT (1) | AT398094B (en) |
| AU (1) | AU644778B2 (en) |
| BR (1) | BR8905454A (en) |
| CA (1) | CA2001299A1 (en) |
| CH (1) | CH677945A5 (en) |
| DK (1) | DK166736B1 (en) |
| ES (1) | ES2019171A6 (en) |
| GR (1) | GR1000659B (en) |
| MX (1) | MX169791B (en) |
| NL (1) | NL8921188A (en) |
| NZ (1) | NZ231148A (en) |
| PT (1) | PT92097A (en) |
| SE (1) | SE467058B (en) |
| WO (1) | WO1990004679A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4106986A1 (en) * | 1991-03-05 | 1992-09-10 | Charles Ulbricht | PACKING SYSTEM DAEMM, INSULATION AND CARRIER PLATE |
| JP2836801B2 (en) * | 1992-03-06 | 1998-12-14 | 日本碍子株式会社 | Papermaking mold, papermaking method and papermaking apparatus for fiber molded product, and paper made fiber molded product |
| JP2836800B2 (en) * | 1992-03-06 | 1998-12-14 | 日本碍子株式会社 | Papermaking mold, papermaking method and papermaking apparatus for fiber molded product, and paper made fiber molded product |
| EP0995836A1 (en) * | 1998-07-27 | 2000-04-26 | Brodrene Hartmann A/S | Method for controlling the local thickness of a moulded pulp product |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB954305A (en) * | 1960-03-30 | 1964-04-02 | Diamond National Corp | Improvements in or relating to the molding of pulp articles |
| US3325349A (en) * | 1964-03-18 | 1967-06-13 | Diamond Int Corp | Method and mold for controlling stock thickness in a pulp molding operation |
| FR2356488A1 (en) * | 1976-06-29 | 1978-01-27 | Sepr | PROCESS AND APPARATUS FOR OBTAINING HIGH-PRECISION MOLDED PARTS IN FIBROUS MATERIALS |
| DK167198B1 (en) * | 1988-10-25 | 1993-09-13 | Hartmann As Brdr | PROCEDURE FOR THE PREPARATION OF FORMED ARTICLES OF A FLUIDIZED CELLULOSE FIBER MATERIAL |
-
1988
- 1988-10-25 DK DK592388A patent/DK166736B1/en not_active IP Right Cessation
-
1989
- 1989-10-23 GR GR890100679A patent/GR1000659B/en unknown
- 1989-10-24 CA CA 2001299 patent/CA2001299A1/en not_active Abandoned
- 1989-10-25 CH CH221290A patent/CH677945A5/de not_active IP Right Cessation
- 1989-10-25 EP EP19890912406 patent/EP0441847A1/en not_active Withdrawn
- 1989-10-25 MX MX1809989A patent/MX169791B/en unknown
- 1989-10-25 JP JP51163389A patent/JPH04502184A/en active Pending
- 1989-10-25 NL NL8921188A patent/NL8921188A/en unknown
- 1989-10-25 CN CN 89108948 patent/CN1025061C/en not_active Expired - Fee Related
- 1989-10-25 BR BR898905454A patent/BR8905454A/en not_active Application Discontinuation
- 1989-10-25 AU AU45133/89A patent/AU644778B2/en not_active Ceased
- 1989-10-25 WO PCT/DK1989/000251 patent/WO1990004679A1/en not_active Application Discontinuation
- 1989-10-25 ES ES8903598A patent/ES2019171A6/en not_active Expired - Lifetime
- 1989-10-25 AT AT903189A patent/AT398094B/en not_active IP Right Cessation
- 1989-10-25 PT PT9209789A patent/PT92097A/en not_active Application Discontinuation
- 1989-10-25 NZ NZ23114889A patent/NZ231148A/en unknown
-
1991
- 1991-04-24 SE SE9101241A patent/SE467058B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| CN1025061C (en) | 1994-06-15 |
| DK592388D0 (en) | 1988-10-25 |
| GR1000659B (en) | 1992-09-25 |
| AT398094B (en) | 1994-09-26 |
| ATA903189A (en) | 1994-01-15 |
| EP0441847A1 (en) | 1991-08-21 |
| ES2019171A6 (en) | 1991-06-01 |
| WO1990004679A1 (en) | 1990-05-03 |
| AU644778B2 (en) | 1993-12-23 |
| DK592388A (en) | 1990-04-26 |
| SE467058B (en) | 1992-05-18 |
| NZ231148A (en) | 1992-10-28 |
| NL8921188A (en) | 1991-08-01 |
| SE9101241L (en) | 1991-04-24 |
| CN1045616A (en) | 1990-09-26 |
| JPH04502184A (en) | 1992-04-16 |
| DK166736B1 (en) | 1993-07-05 |
| CH677945A5 (en) | 1991-07-15 |
| MX169791B (en) | 1993-07-26 |
| SE9101241D0 (en) | 1991-04-24 |
| PT92097A (en) | 1990-04-30 |
| GR890100679A (en) | 1990-11-29 |
| BR8905454A (en) | 1990-05-29 |
| AU4513389A (en) | 1990-05-14 |
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