HIMTONG, Arag (47/3 Moo 3, Khanorm Sub-districtKhanorm District, Nakhonsithammarat, 80210, TH)
CHIABLAEM, Pichai (34 Moo 7, Tontan Sub-districtSaohai District, Saraburi, 18160, TH)
JAMRUSSAMEE, Terdwong (101/91 Moo 7, Klongneung Sub-districtKlongluang District, Pathumthani, 12120, TH)
HIMTONG, Arag (47/3 Moo 3, Khanorm Sub-districtKhanorm District, Nakhonsithammarat, 80210, TH)
CHIABLAEM, Pichai (34 Moo 7, Tontan Sub-districtSaohai District, Saraburi, 18160, TH)
| Claims 1. A process for pre-compacting powder material comprising a step of loading powder materials into a moving mould in combination with reducing volume of the mould after a predetermined volume of soil powder has been loaded into the mould in a manner that it reduces space between particles of powder materials. 2. The process according to Claim 1, wherein loading of powder materials into the moving mould is performed when the mould is continuously moving at a predetermined varying speed along the movement course. 3. The process according to Claim 2, wherein the predetermined volume of powder material is loaded into the mould as two halves wherein the first half of the powder materials is loaded into the mould while the mould is moving at a constant speed and the second half of the powder material is loaded into the mould while the mould is moving at a constant speed lower than that of the first half of powder material when loaded into the mould. 4. The process according to Claims 2 or 3, wherein the first half of the powder material is loaded into the mould while the mould is moving at a speed of 50 meters per minute, and the second half of the powder material is loaded into the mould while the mould is moving at a speed of 25 meters per minute. 5. The process according to Claim 1, wherein the mould volume reduction is achieved by moving at least one movable wall of the mould toward the remaining walls in order to reduce space between the particles of the powder material. 6. An apparatus for forming and pressing powder material comprising A loading and dispensing assembly comprising a powder material reservoir and a loading and dispensing tank defining a hopper capable of holding powder material received from the reservoir; the loading and dispensing tank is movable in response to controlling of the hydraulics device; the loading and dispensing tank communicate with a mould assembly to controllably dispense powder materials into the mould assembly; - A mould assembly comprising a first mould face, a second mould face, a first wall, and a second wall assembled to provide a mould cavity able to receive powder material being dispensed from the loading and dispensing assembly; and wherein at least the first mould face and/or the first wall and/or the second wall is connected and communicates with a hydraulic device and/or pneumatics device and/or motor, and at least the first mould face and/or the first wall and/or the second wall is able to move in response to operation of hydraulic device and/or pneumatics device and/or motor. - A pressing assembly comprising a top plate, a bottom plate, both the top plate and the bottom plate is movable in the X axis; wherein the mould is connected to a frame surrounding it; the frame is further connected to a rail; the frame is further connected to a mould driving mechanism of which drives the mould along the second mould face toward the pressing assembly positioned at far end of the second mould face; the mould assembly is prepared with a means to pre-compact powder material contained inside the mould. 7. The apparatus according to Claim 6, wherein the loading and dispensing tank is realized as a tube connected to a reservoir containing powder material, with the free end of the tube is fitted with open-close valve. 8. The apparatus according to Claim 7, wherein the said tube has an extendable length that allows the said tube to follow the moving mould and is assembled to positioning device and/ or a support and/or a robot arm. 9. The apparatus according to Claim 6, wherein the loading and dispensing tank is realized as a tank situated on a pedestal with a passage and having a first opening for receiving a predetermined volume of powder material discharged from the reservoir and a second opening positioned at the distal end; the second opening communicates with the mould assembly whereby powder material is dispensed through the second opening and the passage of the pedestal into a mould. 10. The apparatus according to claim 6 or 9, wherein the means to controllably dispense powder material of the loading and dispensing tank is by operation of hydraulics and/or pneumatics and/or motor to position the second opening of the loading and dispensing tank to meet with or move away from the passage of the pedestal. 11. The apparatus according to claim 6, wherein the first mould face and the second mould face is prepared with the shape and profile corresponding to the predetermined shape, profile and dimension of the desired product. 12. The apparatus according to claim 6, wherein the second mould face has an extended length starting from where the mould starts receiving powder material stretching toward the pressing assembly and beyond and ending at a point where the compacted green tile is removed from the line. 13. The apparatus according to Claim 6, wherein the first mould face is porous, defining pores uniformly arranged across the entire mould face. 14. The apparatus according to Claim 6, wherein at least the first mould face and/or the first wall and/or the second wall is connected and communicates with the hydraulic device and/or the pneumatics device and/or the motor, enabling the first mould face and/or the first wall and/or the second wall to move so as to reduce the mould's volume and pre-compact the powder material contained inside the mould. 15. The apparatus according to Claim 6, wherein the top plate and the bottom plate of the pressing assembly is prepared with pressing face having the shape and profile correspond to the shape and profile of the mould face of the mould assembly and the shape, profile and dimension of a product. 16. The apparatus according to Claim 6, wherein the pressing face of the top plate is integral with the top plate and/or is a separate piece assembled thereto and may be removed and replaced. 17. The apparatus according to claim 6, wherein the pressing face of the top plate is prepared with the shape, profile and dimensions corresponding to the shape, profile and dimensions of the first mould face. 18. The apparatus according to Claim 6, wherein the pressing face of the bottom plate is prepare with the shape and profile and dimensions correspond to shape, profile and dimensions of the second mould face. 19. The apparatus according to Claim 6, wherein the pressing face of the top plate is prepared with the shape, profile corresponding to the shape, profile and of the first mould face. 20. The apparatus according to Claim 6, wherein the pressing face of the bottom plate is prepared with the shape and profile and identical to the shape and profile and of the second mould face. 21. A method for forming powder material into a product utilizing the apparatus according to any one of Claims 6 to 20 comprising a step of: -Loading a predetermined volume of powder materials into a mould; -Pre-compacting the powder material contained inside the mould prior to subjecting the pre-compacted powder material to a high-pressure press; -Pressing the pre-compacted powder materials under high pressure; wherein the pre-compaction of the powder material is accomplished by loading powder material into a mould moving at a predetermined speed in combination with subsequent reduction of mould volume after powder material is completely loaded into the mould such that the space between particles of the powder material is reduced and compacting the powder material to form the shape, profile and dimensions corresponding to the shape, profile and dimensions of the mould. 22. The method according to Claim 21, wherein the predetermined volume of the powder material correspond with the compaction ratio of the powder material after pressing and correlate to a predetermined thickness of a product. 23. The method according to Claim 21, wherein the predetermined volume of powder material is gradually loaded into the mould while the mould is continuously moving forward toward the pressing assembly at a predetermined speed. 24. The method according to Claim 21 or 23, wherein loading of predetermined volume of powder material into the mould is performed while the mould is continuously moving forward toward the pressing assembly at a varying speed. 25. The method according to Claim 23 wherein the predetermined volume of powder material is loaded into the mould as two halves wherein loading of the first half of powder material is performed while the mould is moving at a constant speed higher than the speed of the mould while loading the second half of powder material. 26. The method according to Claim 25, wherein during loading of the first half of predetermined volume of powder material, the mould is moving at a speed of 50 meters per minute and wherein during loading of the second half of the predetermined volume of the powder material, the mould is moving at a speed of 25 meters per minute. 27. The method according to Claim 21, wherein reducing mould volume is performed by operatively moving at least the first mould face and/or the first wall using the hydraulic device and/or pneumatics device and/or motor connected to and communicating with at least the first mould face and/or first wall to compact the powder material contained inside the mould forming the shape, profile and dimensions corresponding to the shape, profile and dimensions of the mould. 28. The method according to Claim 21, wherein the step of high-pressure pressing of powder materials is performed subsequent to the pre-compaction step. 29. The method according to Claim 28, wherein the step of high-pressure pressing comprising a step of: - Transferring the pre-compacted powder material from the mould onto the pressing assembly; Positioning of the pre-compacted powder material inside a cavity of the pressing assembly; and - Applying high-pressure onto the pre-compacted powder material encased inside the cavity of the pressing assembly. Wherein, subsequent to high-pressure pressing, the powder materials form into a product having the shape, profile and dimensions corresponding to the shape, profile and dimensions of the pressing face of the pressing assembly |
1
METHOD AND APPARATUS FOR FORMING AND PRESSING POWDER MATERIALS
Technical Field
The present invention relates to mechanical and electrical engineering, in particular to 5 the field of forming and pressing powder materials, especially for producing ceramic tiles and the production method thereof.
Background of the Invention
A conventional method for forming and pressing powder materials such as in the ceramic tile industry is by dry pressing soil powder within a mould. The ceramic tiles 10 produced according to such method are usually less complicated in shape and profile. The method involves loading loose soil powder into a pressing mold via a grid. The soil powder inside the mold is leveled and lightly compacted to achieve a uniform compaction and subsequently is subject to high-pressure pressing. The disadvantage of this method is that it is unable to produce tiles with complicated shapes and profiles, such as curved tiles.
15 European Patent No. EP 0894588 disclosed a method for forming ceramic tiles by means of partially isostatic moulds comprising loading the powder to be pressed into the mould cavity, followed by exerting a uniform pressure on the entire surface of the powder present in the mould cavity, releasing the pressure, and partially opening the mould to facilitate powder deaeration. Then, pressure is exerted on the first portion and subsequently
20 on the second portion of the mould cavity, with simultaneous nullification of the pressure on said first surface portion of the powder contained in the mould cavity and then pressure is exerted on said first and on said second portion alternately. The invention also disclosed a press for implementing the method. The press comprising punch comprises a cavity a lattice positioned within said cavity and defining a plurality of cells an elastic membrane securely
25 fixed to the edges of said cavity and of said lattice. The cells, being connected to a pressurized oil source via a distributor valve, are arranged to connect the cavity alternately to said source and to discharge. The distributor valve generates close-together pressure pulses which are applied within the cell. The disadvantage of this method is that there is a need to partially open the mould to facilitate deaeration, which complicates the manufacturing process and apparatus. In addition, it would be impossible to produce product with more complicated shape and profile such as curved tile via this method.
International patent publication No. WO 1998023424 disclosed an improved method of forming curved ceramic tile by pressing dry soil powder. The method comprises distributing powders on flexible conveyor means and advancing said powders along a direction of advance through a pressing station containing said powders on said conveyor means by containing means in said pressing station pressing said powders in said pressing station, wherein said containing means act on the powders to be pressed during said advancing and those containing means continue to act during said pressing. The compacted layer is transferred towards the mould means and a portion of the compacted layer is severed and pressed by descending the punch towards the bottom portion at the mould means. The disadvantage of this method is that the powders acted on by the containing means during the advancing and pressing are more likely to produce product with an uneven surface, which will then require a further beautifying processes. " European Patent No. EP0629495 disclosed a modular hydraulic press for producing ceramic items including curved tile. The press utilizes multiple moulds in successive cycles to press the ceramic powder into the required shaped. The disadvantage of this invention is that as multiple numbers of moulds are used, it requires extensive amount of time, labor and resources to maintain the system. It would potentially bring the manufacturing process to a halt if several of these moulds were broken.
Therefore, it is an object of this invention to provide a method and apparatus for forming and pressing powder materials, in particular, soil powder, into a product such as tile, to provide a method and an apparatus to efficiently and easily form product with more complicated shapes and dimensions while maintaining the simplicity of the mould, and to provide an alternative to resolve the above-discussed disadvantages of the existing prior art.
Summary of the invention
The present invention disclosed a method and apparatus for forming and pressing powder materials. One aspect of the invention provides a method for pre-compacting the powder materials to form powder materials. The said method comprises a step of loading powder materials into a mould which is moving at a predetermined speed in combination with reducing the volume of the mould after the powder has been loaded into the mould in order to further pre-compact the powder material inside the mould. In another aspect, the invention provides a method for forming powder materials comprising a step of loading a predetermined volume of powder material into a mould, pre-compacting the powder material inside the mould and subjecting the pre-compacted powder material to high-pressure pressing. hi a further aspect of the invention, the invention provides an apparatus for forming powder material comprising a powder material loading and dispensing assembly, a mould assembly and a press assembly. The material loading and dispensing assembly comprises a powder material reservoir, which is a loading and dispensing tank that receives powder materials from the reservoir and controllably dispenses the powder material into a mould. The mould assembly comprises a first mould face, a second mould face, a first wall and a second wall assembled together to form a cavity able to receive powder material being dispensed from the loading and dispensing assembly. The mould assembly is able to move by controlling the mould movement mechanism which connects to and communicates with the mould assembly moving the mould assembly toward the pressing apparatus. The pressing apparatus comprises a top plate and a bottom plate, both of which able to move up and down in X axis. The pressing apparatus applies pressure onto pre-compacted powder materials which have been transferred on the pressing apparatus, forming the powder materials into a product.
Brief Description of Drawings The accompanying drawings illustrate various embodiments of the principles described herein and are a part of the specification. The illustrated embodiments are merely examples and do not limit the scope of the claims.
Fig. 1 shows a side view of an embodiment of the apparatus for forming and pressing tile according to an example of the present invention; Fig. 2 shows an elevated perspective view of the relationship between the loading and dispensing tank and a mould assembly;
Fig. 3 shows an elevated cross-sectional view of the relationship between the loading and dispensing tank and a mould assembly of Fig. 2 and illustrates soil powder inside the loading and distributing tank and mould; Fig. 4 shows a side view of an embodiment of the apparatus for forming and pressing tile according to an example of the present invention where the loading and dispensing tank is loading soil powder into a mould and the loading and dispensing tank and the mould are moving toward a pressing assembly; Fig. 5 shows a side view of a pressing assembly with the bottom plate moved downward;
Fig. 6 shows a side view of the apparatus for forming and pressing the tile in Fig. 4 after the loading and dispensing tank has loaded the soil powder into the mould and the mould has moved beyond the pressing assembly;
Fig. 7 shows a side view of the apparatus for forming and pressing the tile in Fig. 6 in which the mould has been driven back to return to the position where the pressing assembly is located to compensate and evenly distribute the soil powder inside the mould;
Fig. 8 shows a side view of the apparatus for forming and pressing tile of Fig. 7 in which a first wall of the mould is moved toward a first mould face and a second wall in order to encase and pre-compact the soil powder inside the mould; Fig. 9 shows a side view of the apparatus for forming and pressing the tile in Fig. 7 in which the bottom plate of the pressing assembly is moved downward and the pre-compacted soil powder is transferred from the mould onto the pressing face of the bottom plate;
Fig. 10 shows a side view of the apparatus for forming and pressing tile of Fig. 8 and 9, in which the mould assembly has returned to resume its position and has started to receive a new load of soil powder while the pressing assembly performs high-pressure pressing of the previous load of soil powder;
Fig. 11 show a side view of the apparatus for forming and pressing tile according to the example of the present invention, in which the mould is receiving a new load of soil powder and is moving toward the pressing assembly, wherein the pressing assembly has completed its high-pressure pressing and the soil powder has been compacted into a green tile.
Fig. 12 shows a side view of the apparatus for forming and pressing tile of Fig. 10 in which loading of the new load of soil powder has been completed and the mould has moved beyond the pressing assembly and has pushed the green tile away from the pressing assembly to be further processed. Detail Description of the Invention
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present systems and methods. It will be apparent, to one skilled in the art, however, that the present apparatus, systems and methods may be practiced without these specific details. Reference in the specification to "an embodiment," "an example," or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least that one embodiment, but not necessarily in other embodiments. The various instances of the phrase "in one embodiment" or similar phrases in various places in the specification are not necessarily all referring to the same embodiment.
The present invention provides a method and apparatus for forming powder materials, for example soil powder, ceramic powder, metallic powder, etc. We will first describe an example of the method and then an embodiment of the apparatus.
Method for Forming Powder Material The method for forming powder materials according to the present invention comprises a step of continuously loading the material into a mould, pre-compacting the material, and pressing the pre-compacted materials utilizing an apparatus which will be further described.
Material Loading
In the loading materials step, the powder materials are prepared by known methods which could be either dry method and wet method such as spray drying. A predetermined amount of powder materials are loaded into a mould while said mould is moving toward the pressing apparatus (in order to be pressed into a final product). The powder materials have been pre- compacted in a manner that reduces their disintegration while being transferred from the mould to the pressing apparatus to be pressed into a final product, wherein: A predetermined amount of the powder materials means a volume of powder materials which correspond with the size and shape of the mould and which is relative to the compaction ratio of the materials after being pressed whereby a product having desired compaction and thickness is formed. The mould for forming the product may be of any shape and configuration in accordance with the desired shape and profile of the product. The mould's shapes and configurations should also correspond with the shape and configuration of the pressing apparatus so that the shape , profile and dimension of the pre-compacted powder material once transferred on the pressing apparatus will match with the pressing faces of the pressing apparatus for efficient pressing The predetermined volume of the powder materials are successively distributed into the mould wherein: The mould is moving toward the pressing apparatus by a known means such as a motor or a belt pulley The mould is moving at a predetermined speed while receiving the powder materials. The speed may be varied. Preferably, the powder materials to be loaded is loaded as two into the mould a haft at a time and the speed of the mould while receiving the first half of the predetermined volume of the powder materials should be higher than the speed of the mould while receiving the second half of the predetermined volume of the powder materials. Setting the speed of the mould while receiving the first half of the predetermined volume of the powder materials to be higher than the speed of the mould while receiving the second half of the predetermined volume allows the powder materials to be efficiently driven inside to fill the mould cavity. Once approximately the entire first half of the predetermined amount of the materials is loaded into the mould, the speed of the mould is reduced and the second half of the powder materials is loaded to completely fill the mould. The movement of the mould while the materials are being loaded into the mould will cause the powder materials inside the mould to move and will provide some compaction of the powder materials contained therein. Different speed settings may be needed for different types of powder materials. By moving the mould at a suitable speed, the particles of the powder materials are able to align and stay close together, resulting in a certain level of compaction deriving a pre-compacting stage of the powder materials. The speed of the mould also correlates with the volume of the powder materials to be loaded into the mould. Preferably, the entire predetermined volume of the powder materials should be loaded into the mould prior to when the moving mould reaches the pressing apparatus, or at least by the moment the mould reaches the pressing apparatus. Ideally, the mould should move beyond the pressing apparatus to a distance of approximately the length of the mould and then be driven back with a thrust to the position where the pressing apparatus is located in order for the mould to be pressed. The backward thrust helps the powder material inside the mould disperse evenly, resulting in a more uniform thickness and consistency of the product after pressing.
Pre-compacting The principle of pre-compaction is to allow the particles of the powder material to be as close to each other as possible so as to achieve some level of compaction of the powder material before the final pressing in which the pre-compacted material is pressed into a final shape and form or a product. The pre-compacting occurs before the pressing so that the pre- compacted material facilitate pressing in a way that, for example, reduces disintegration of the material while being transferred (from a mould) so that the pre-form shape is maintained. Pre- compacting also helps to ensure product consistent thickness and thus reduce cracks or breaking or misshapenness of the product. Ideally, the mould (mould's cavity) at the pre- compacting stage has a shape, profile and dimension that corresponds to the shape, profile, dimension and configuration of the mould (cavity) of the pressing apparatus.
The powder materials loaded inside the mould is pre-compacted by reducing the space or distance between the particles of the powder so that the particles are closer to each other and become denser and thus pre-compacted. The method, in accordance with the present invention, is achieved by loading the powder materials into a forward moving mould, with the speed of movement driving the powder particles closer to each other and thus making them denser, thereby achieving continuous pre-compaction at the same time the powder materials are being loaded into the mould. Pre-compaction may occur in combination with reduction of the volume of the mould. The reduction of the volume of the mould may be achieved by utilizing a mould with movable components, such as movable walls. The wall movement may be controlled by known devices such as hydraulics, pneumatics, or electrical motors.
Pressing
The powder materials which have been pre-compacted will be subsequently pressed by the pressing apparatus. The pressing apparatus has a pressing face and cavity corresponds to the shape and configuration of the mould at the pre-compacting stage. The pre-compacted powder material is pressed at a predetermined pressure in order to be completely compacted, and the desired uniform mass density of the product is obtained once subjected to further processing by heating or firing.
In order to better understand the principle of the method and apparatus for forming and pressing powder material according to the invention, the method and the apparatus will now be discussed by way of examples as follows: Apparatus for Forming Powder Materials
An example of the method and apparatus for forming powder material into roof tiles
An embodiment of the apparatus, made of rigid materials, for forming powder materials, such as soil powder, in accordance to the principles of the present invention comprising soil powder loading and distributing assembly, mould assembly and pressing apparatus as shown in Fig. 1.
Soil powder loading and dispensing assembly
The soil powder loading and dispensing assembly comprises a soil powder reservoir (22), a loading and dispensing tank, (30) defining a hopper capable of holding soil powder receives from a reservoir (22). The loading and dispensing tank (30) is movable (by operation of mechanisms such as motors and hydraulics) and communicates with a mould assembly whereby the loading and dispensing tank (30) receives soil powder from the reservoir (22) via a first opening (31) and interacts with the mould assembly to controllably dispense the soil powder into a mould (40) via a second opening (32) located at the distal end. Fig. 1 shows a preferred embodiment of the soil powder loading and dispensing assembly. In this embodiment, the loading and dispensing tank (30) is provided with a first opening (31) which receives soil powder from the reservoir (22) and a second opening (32) which dispenses the soil powder into the mould (40). The loading and dispensing tank (30) is situated on a pedestal (33) wherein the second opening (32) is facing a top face of the pedestal (33) and is able to move forward and backward by a hydraulic control, relative to the length of the pedestal (33). The pedestal is prepared with a passage (34) located on the length within the moving path of the loading and dispensing tank (30). Preferably, the loading and dispensing tank (30) is situated on the pedestal (33) with a sharp angle so as to increase flowability of the soil powder from the loading and dispensing tank (30) into the mould (40). In an idle position, the second opening (32) of the loading and dispensing tank (30) would position away from the passage (34) of the pedestal, and thereby the second opening (32) would be in a closed state as the top face of the pedestal prevents the soil powder from flowing into the mould. When dispensing is needed, the loading and dispensing tank (30) is moved by directing the hydraulic control to position the second opening (32) at the mouth of the passage (34) of the pedestal (33), thereby the second opening (32) would be in an open state, releasing the soil powder from the loading and dispensing tank (30) into the mould (40) via the passage (34) of the pedestal (33). After a predetermined volume of the soil powder is dispensed into the mould (40), the loading and dispensing tank (30) is either moved forward or backward away from the mouth of the passage (34) so as to withhold dispensing and resume the close state of the loading and dispensing tank (30). In another embodiment (not shown) of the loading and dispensing assembly, a soft powder feeding tube is provided which connects the reservoir (22) to the mould (40), wherein the powder materials are loaded into the mould (40) via the feeding tube. The said feeding tube has an extendable length such that the end of which the powder material is being discharged from, able to follow the moving mould and may be connected to a positioning or support device or robot arm in order to guide the feeding tube to discharge the powder materials into the mould (40), including when the mould (40) is moving in the powder forming line. The ability to control the release and the arrest of the powder material may be achieved by installation of an open-close member such as an open-close valve at the connecting point between the reservoir (22) and the feeding tube or at the free end of the feeding tube.
Mould Assembly
As shown in Fig. 4, the mould (40) receives soil powder from the loading and dispensing tank (30) and pre-compacts the soil powder contained therein through its movement while receiving the soil powder and /or in combination with reduces its volume after the soil powder is completely dispensed into it. The resultant pre-compacted soil powder with uniform density and with the desired shape and profile is then transferred to the pressing assembly (50) for final pressing.
The shapes of the mould (40) ideally correspond with the desired shape, profile, and dimensions of the product. The mould (40) comprises a first mould face (42), a second mould face (44), a first wall (46), and a second wall (48) assembled together to form a mould cavity, thereby, capable of accommodating soil powder dispensed from the soil powder loading and dispensing tank (30). The shapes, profile, dimensions of the mould (40), in particular, of the first mould face (42) and the second mould face (44) correspond to the shape, profile and dimensions of the desired tile. The second mould face (44) is preferably fixed to a position and has an extended length starting from where the mould starts receiving soil powder and stretching toward the pressing assembly (50) and beyond, ending at a point where the compacted green tile is removed from the line. The second mould face forms a moving path of the mould assembly. That is, the first mould face (42) including the first wall (46) and the second wall (48) are able to move (glide) along the length of the second mould face (44) toward the pressing assembly. As shown in Fig. 2, the mould (40) (i.e. 42, 46, 48) is assembled onto a frame (36) wherein the frame (36) is on the same plane with the mould (40) such that it surrounds the mould (40), except on the second wall (48) which is not assemble to the frame (36). The frame (36) is movably assembled to the rail (35) whereby the mould (40), upon operating of the mould (40) driving mechanism (24), the mould (40) is able to move, relative to the rail (35), toward pressing assembly (50) as shown in Figs. 6-8. The mould (40), after transferring pre-compacted soil powder to the pressing assembly (50), is able to move back, relative to the rail (35) to resume its position ready to receive a new load of soil powder from the soil powder loading and dispensing tank (30).
As shown in Fig. 3, the first mould face (42) is porous, so that the air is able to escape through the pores uniformly arranged across the entire mould face when mould (40) is filled with soil powder during pre-compacting stage. As the air is replaced with the soil powder, it increases the compaction ability of the mould (40); reducing the air pocket inside the mould (40), thereby improves the quality of the pressing and ultimately the quality of the product (mass of the product contains no or less air pockets and thus quality is ensured). In addition, allowing the air to escape while pre-compacting helps to reduce pressure inside the mould (40) for better compaction and ease in transferring the pre-compacted soil powder from the mould (40); wherein
The shape and configuration of the first mould face (42) correspond with the shape and configuration of the second mould face (44) and the shapes and configuration of the first mould face (42) and the second mould face (44) correspond with the shape and dimensions of the desired tile. A preferred embodiment of the second mould face (44) is as shown in Fig. 2 and 3. In this embodiment, the second mould face (44) is has an extended length toward the pressing assembly and beyond. The second mould face (44) is fixed to a position, the first mould face (42) including the mould walls (46, 48) are able to move (glide) along the length of the second mould face (44) bringing the soil powder contained inside the mould (40) toward the pressing assembly (50). Preferably, the second mould face (44) has a length stretching beyond the pressing assembly (50) whereby once the soil powder is pressed into a green tile, the green tile may continue to move along the second mould face (44) to the next processing step.
As described above, the mould (40) comprises the first wall (46) and the second wall (48). The first wall (46) is positioned opposite the second wall (48) with a distance correlative to the size of the desired product. The first wall (46) is operatively movable by controlling mechanical means, such as hydraulic system, pneumatics devices or motors connected to the said first wall (46) to reduce the volume of the mould (40) in order to pre-compact the soil powder inside the mould (40)in addition to pre-compaction as a result of moving mould (40). Prior to loading soil powder into the mould (40), the first wall (46) is positioned away from the first mould face (42) while remaining in contact with the second mould face (44). While the loading and dispensing tank (30) is loading the soil powder into the mould (40), the mould (40) is moved (via operation of the mould driving mechanism) toward the pressing assembly (50) while continuing to receive the load (as shown in Fig. 2). The mould (40) is moved beyond the pressing assembly (50) to a proximate distance that is equal to or greater than the distance between the first wall (46) and the first mould face (42) (at the time prior to receiving the load) as shown in Figs 6 and 7. The mould (40) is then driven back with a thrust to a position where the pressing assembly (50) is located in order to compensate the soil powder inside the mould (40) to evenly fill the mould cavity. Thereafter, the first wall (46) is moved toward the second wall (48) compressing the soil powder inside the mould (40) as shown in Fig. 8, pre-compacting the soil powder into a shape correspond to the shape of the mould (40) ready to be transfer to the pressing assembly (50) for further pressing.
Pressing Assembly
Pressing assembly (50) is located next and after the mould assembly on the production line as shown in Fig. 4. The pressing assembly (50) comprises a top plate (52) and a bottom plate (54) wherein the bottom plate (54) is situated opposite the top plate (52). The top plate (52) and the bottom plate (54) are able to move, via operation of known mechanisms such as hydraulics, in the X axis, as shown in Fig. 5. The pressing face (56) of the top plate (52) and the pressing face (56a) of the bottom plate are prepared with a shape and configuration corresponding to the shape and configuration of the first and second mould face (42, 44) of the mould (40) and as well as corresponding to the shape of desired product. The pressing face (56) of the top plate (52) may be integrally formed. Preferably, the pressing face (56) of the top plate (52) is provided as a separate piece wherein the pressing face (56) is secured to the top plate (52) by appropriate securing means such as a bolt or the like and the pressing face (56) may be replaced with a pressing face with a different shape and profile if desired or may be removed for maintenance or replaced when worn. The pressing face (56a) of the bottom plate (54) should also be prepared with a shape and profile that corresponds to the shape and profile of the second mould face (44) of the mould (44). Preferably, the pressing face (56a) of the bottom plate (54) is identical to the second mould face (44) of the mould (40), as if it is part of the second mould face (44) the pre- compacted soil powder being transferred from the mould (40) on to the pressing face (56a) will be well received.
In operation, once the pre-compacted step is completed and the mould (40) is positioned at the pressing assembly (50), i.e. between the top plate (52) and the bottom plate (54), the pre-compacted soil powder is then transferred from the mould (40) onto the bottom plate (54). This is done by lowering the bottom plate (54) in the X axis to a distance not less than the thickness or height of the pre-compacted soil powder, and thereby creating a cavity between two sections of the second mould face (44) and the bottom plate (54). The cavity accommodates the pre-compacted soil powder which has just been transferred from the mould (40). Once the transfer is completed, the mould (40) is moved away from the pressing assembly (50) to the starting position to receive the next load of soil powder. The top plate (52) is then moved in X axis toward the bottom plate (54) wherein the profile of the pressing face (56) matches with the profile of the pre-compacted soil powder, the top plate (52) is then performs high-pressure pressing encasing the pre-compacted soil powder between the top plate (52), the bottom plate (54) and the two sections of the second mould face (44), the pre- compacted soil powder thereby is formed into the final shape of the desired product. After the high-pressure pressing is completed, the top plate (52) is moved away to resume its position and the bottom plate (54) moves upward until the surface of the pressing face (56a) is leveled with the second mould face (44)'s surface. The formed product is then pushed away from the pressing assembly (50) by the oncoming mould carrying the next load to the pressing assembly (50). The formed product may also be moved mechanically or manually along the second mould face (44) toward the next processing station. The first mould face (42), the second mould face (44) of the mould (40), the top plate (52), and the bottom plate (54) have corresponding shapes, profiles, and dimensions which may be removed and replaced with different shapes, profiles and dimensions to produce products with different shapes, profiles, and dimensions.
Method for Forming Powder Materials
By utilizing the principle of the afore-described apparatus, the method for forming powder material — in particular, a method for forming powder material into a tile according to an example of the present invention — comprises a step of:
-Loading a predetermined volume of soil powder into a mould using a loading and dispensing assembly. The soil powder is dispensed from the reservoir into the loading and dispensing tank, and subsequently controllably loaded into the mould by allowing the loading and dispensing tank to open and close as desired. A predetermined volume of soil powder, preferably, corresponds to the dimensions of the desired tile. In addition, the volume of the soil powder must also correspond with the soil powder compaction ratio which will translate into tile thickness after pressing. When the soil powder is dispensed into the mould, the entire volume of the predetermined volume of the soil powder may be loaded into the mould at one time. However, for a better results and better distribution of the soil powder inside the mould, it is preferable that the predetermined volume of the soil powder is gradually loaded into the mould while the mould is moving forward toward the pressing assembly. For a better pre- compaction of the soil powder loaded inside the mould, it is preferable that the mould is moved at varying speeds starting from when the soil powder is first loaded into the mould until the loading of the predetermined volume of the soil powder into the mould is completed. Preferably, the predetermined volume of the soil powder is loaded into the mould as two halves. While loading the first half of the predetermined volume of the soil powder, the mould is moved while continuing to receive the soil powder being loaded into it at the speed of 50 meters per minute. As the mould is moved, the loading and dispensing tank is also moved at the same speed. Once loading of the first half of the predetermined volume of the soil powder is completed, the second half of the soil powder is then loaded into the mould while the speed of the mould is reduced to 25 meters per minute. Reducing the speed of the mould while loading the second half of the soil powder into the mould helps to even the density of the first half and the second half of the soil powder inside the mould so as to achieve uniform density once pressed for a higher quality product. Without reducing the speed of the mould, the first half of the soil powder tends to have higher density than that of the second half, resulting in uneven density and ultimately inferior quality and/or damaged products. Preferably, once the predetermined volume of the soil powder is completely loaded into the mould, the soil powder is once again manipulated to even out the soil powder density inside the mould by allowing the mould to move forward, and once loading the soil powder is completed .and the mould has moved beyond the pressing assembly, the mould is driven backward with a thrust to a position of the pressing assembly. Vigorous movement of the mould causes the soil powder contained therein to spread out and evenly fill the mould cavity and become ready through uniform pre- compacted for further pre-compaction;
- Pre-compacting the soil powder inside the mould. At this step, the soil powder which has been compacted to some level as a result of the movement of the mould while receiving the loading of soil powder is subjected to additional pre-compaction via reducing the volume of the mould. As earlier described, pre-compaction occurs both during loading of the soil powder into the mould as well as after loading is completed. After loading is completed, the soil powder may be further pre-compacted by reducing the volume of the mould. Pre- compaction during loading the soil powder has been discussed. The pre-compaction of the soil powder after the completion of loading by reducing volume of the mould will now be described. Preferably, once loading of the soil powder into the mould is completed and the mould has moved to the location of the pressing assembly, pre-compaction by way of reducing mould volume then occurs by operation of the mould mechanism. As mentioned in the apparatus discussion, the mould is designed to comprise at least one movable wall which is able to move so as to reduce volume of the mould when needed in order to compact the powder material — in this particular example, the soil powder inside the mould. Li accordance with one embodiment of the present invention, the volume reduction of the mould may be achieved by providing the mould with a means to control movement of at least one wall of the mould, namely by using known devices or apparatuses such as hydraulics, pneumatics, and motors or the like. The means to control movement of the wall, the hydraulic system, the pneumatics system, or the motor is connected or able to communicate with the mould's wall, that is designed to be movable. By operating the wall control movement device, the wall will be able to move when needed to reduce volume of the mould and thereby compact the content inside the mould. In one example, the first wall of the mould is movable. By moving the first wall toward the second wall once loading is complete, the soil powder contained inside the mould is compacted and formed into the shape, profile, and dimensions corresponding to the shape, profile, and dimensions of the mould cavity, which in turn corresponds with the shape, profile, and dimensions of the desired tile. Preferably, the a pressure of not less than 10 bars is applied to the mould to pre-compacted the powder material contained* inside the mould. The process provides pre-compaction of the soil powder, limiting flowability of the soil powder so that transfer of the soil powder from the mould to the pressing apparatus can be easily done and the pre-compacted shape and profile are retained. After pre-compaction, the pre- compacted soil powder is then further subjected to high-pressure pressing so as to produce a final formed tile; and
-High-pressure pressing. Soil powder which has been pre-compacted is subjected to further pressing at a predetermined pressure, preferably, as an illustration and not a limitation, the pressure to compact the pre-compacted powder material in this example is about 200 bars. This step is a high-pressure pressing so as to further compact the pre-compacted soil powder into its final form as a product with the required shape, profile and mass density which is retained after the firing process. In one example, at this step, the soil powder which has been pre-compacted is positioned at the pressing assembly. The pre-compact soil powder is then transferred onto the bottom plate of the pressing assembly by lowering the bottom plate in the X axis to a distance not less than the thickness or height of the pre-compacted soil powder, thereby creating a cavity between two sections of the second mould face and the bottom plate. The cavity accommodates the pre-compacted soil powder which has just been transferred from the mould. Once the transfer is completed, the mould is moved away from the pressing assembly. The top plate is then moved downward in the X axis toward the bottom plate wherein the profile of the pressing face matches with the profile of the pre-compacted soil powder. A predetermined pressured is then applied to the pre-compacted soil powder encased between the top plate, the bottom plate and the two sections of the second mould face, thereby compacting the pre-compacted soil powder into a green tile with a shape corresponding to the shape of the pressing face of the pressing assembly ready for firing. Regarding forming of powder materials according to the present invention, the shape of products such as tiles may be changed to various shapes by changing the shape and configuration of the mould face of the mould assembly and/or pressing face of the top or bottom plate of the pressing assembly or combination thereof.
By employing the method and utilizing the apparatus for forming powder materials according to the present invention, it is possible to efficiently and easily form product with more complicated shapes and dimensions while maintaining simplicity of the mould. The resultant tile has consistent quality with uniform mass density and thickness reducing the product deformation after firing which causes inconsistent mass density due to poor compaction practices.
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