Background of the Invention Plastic is a synthetic polymers made of oil and natural gas. Plastic were introduced less than 100 years ago and quickly become the world's most use material, especially in packaging and containers manufacturing industries. The plastic materials commonly used for article moulding are polypropylene (PP), polystyrene (PS), and polyethylene (PE). However, there are many drawbacks associated with the use of plastic as raw materials for packaging or containers. Plastic is a major part of household waste and is non-biodegradable. It can take hundreds of years to break down in landfill. Plastics generate toxic emissions if incinerated and although some plastics can be recycled, the recycling process in many cases can be more expensive than the original material. Waste plastic litters found in rivers and seas where it is responsible for the deaths of thousands of seabirds, sea mammals and fish.

Recently, paper pulp moulded packaging and containers have starting to replace the plastic products. The pulp moulded products are biodegradable, recyclable, and more environmental friendly. However, the pulp moulded products have several drawbacks. These products are preferably made from recycled pulp obtained from recycled newsprint or other recycled paper.

Generally, the paper recycling process involved pulping, screening, de-inking, bleaching and refining, which is costly and energy consuming. Furthermore, various chemicals are used during the recycling process, which may cause environmental pollution if proper controls are not executed.

Fibre bearing material such as rice husk, straws, oil palm empty fruit bunch and frond are abundantly available in Asia country. These fibre bearing materials which are usually being abandoned may be used as raw material to replace paper pulp for making plant fibres moulded packaging and containers. Furthermore, the plant fibres slurry need not high cost of preparation before it is moulded into shape compared to paper pulp. Therefore it would be an advantage to transform the existing paper pulp moulding process to manufacture plant fibre moulded products.

Most of the current plant fibres moulded article forming machine are heavily manual driven and comprising only one thermal-press moulding station. The wet fibre moulded product formed at the forming station needs to be transferred manually together with the attached filtering net to the thermal-press moulding station for drying and shaping. This action may cause destruction to the filtering net. Furthermore, the time require for thermal-pressing operation is substantially longer than the mould forming operation. Therefore it is not practical of having only one thermal-press station in the moulding machine.

Therefore it is an object of the present invention to provide a fully automatic machine for moulding articles from plant fibre slurry.

Another object of the present invention is to provide a plant fibres moulded article forming machine having at least one thermal-press station located at each side of the forming station to increase the production efficiency.

A further object of the present invention is to increase the speed of conveying operation by having an independent conveyor system attached to the corresponding thermal-press station in the plant fibres moulded article forming machine.

Yet another object of the present invention is to produce diluted plant fibres slurry comprising of water, 0.05% to 1.0% of fibres content, and 0.01% to 30% of food graded water resistant agent and oil resistant agent.

Summary of the Invention The present invention relates to an automatic device for producing moulded plant fibre product from plant fibre slurry comprising a moulding station having a moulding means for forming a wet moulded article; at least one thermal forming station positioned at each side of said moulding station in order to dry and shaped said wet moulded article ; and characterized in that each thermal forming station is attached with an independent conveyor system whereby the finished plant fibre moulded article produced from each thermal forming station can be sent off from the device efficiently.

The moulding station consists of an upper transferring chamber and a lower perforated mould mounted within a slurry tank. The transferring chamber having an upper platen carries a forming mould to receive a wet fibre moulded article form on the lower perforated mould.

The wet fibre moulded article is then transferred from the upper forming mould to the lower thermal moulding die and the upper thermal moulding carried on a upper platen is lowered into contact with the lower thermal moulding die in the thermal forming station.

At this stage the wet fibre moulded article is dried and shaped. The dried finish moulded article is deposited onto a conveyor and sent off from the automatic moulding machine for post processing such as trimming and sterilization.

Brief Description of the Invention Figure 1 shows a front view of an automatic device for manufacturing plant fibre moulded article from plant fibre slurry.

Detailed Description of the Invention An automatic moulding device (1) for manufacturing a plant fibre moulded article from plant fibre slurry as shown in Fig 1 comprises of a relatively massive framework which includes uprights (10,11) and cross-member (12). In use, the uprights (10,11) are fixed to the ground.

The moulding device (1) generally consists of a moulding station for making a wet plant fibre moulded article, and a thermal forming station is positioned at each side of the moulding for drying and shaping of the wet article.

The moulding station has an upper transferring chamber (21) being mounted to the cross member (12) of the framework. A slurry tank (4) is aligned vertically at the bottom of the upper transferring chamber (21) for receiving plant fibre slurry via a pipe (not shown).

The upper transferring chamber (21) is provided with an upper vacuum platen (22) which has mounted thereon a forming mould (23). The upper platen (22) carries the forming mould (23) which may be a male die are mounted to a moving means to reciprocate the upper transferring chamber (21) towards and away form the slurry tank (4). In a preferred embodiment of the present invention, the moving means is a pneumatic ram (24). Other moving means such as hydraulic ram or electric motor may be applicable for the present invention. The upper transferring chamber (21) reciprocates in a vertical direction only, for the purpose of transferring the wet fibre moulded article from the moulding station (20) to the thermal forming station (30).

A perforated moulding tool (5) which is associated with a vacuum means is mounted within the slurry tank (4). Preferably, the perforated moulding tool (5) is a female die as to match the female forming mould (23) to produce a wet fibre moulded article with constant thickness. A layer of filtering net or sieve is secured onto the contour of the forming mould (23) for the purpose of retaining the plant fibres and allowing the water of the plant fibre slurry to pass through.

At each side of the moulding station is allocated with one thermal forming station, namely first thermal forming station and second thermal forming station. Both of the forming station comprising an upper thermal chamber (30,40) and a lower thermal chamber (50,60). The significance of this feature is that the time required for thermal forming operation is substantially longer than the time required for the moulding operation. Therefore by having the forming station at each side of the moulding station can increase the speed of production.

The upper thermal chamber (30,40) of the respective first and second thermal forming station comprising an upper thermal platen (31,41) which has mounted thereon a male moulding die (32, 42). The upper thermal platen (31, 41) and the male moulding die (32, 42) are mounted on a pneumatic ram (33,43). The pneumatic ram (33,43) is responsible for the vertical reciprocating movement of the upper thermal chamber (30,40) in the thermal forming station.

The lower thermal chamber (50,60) of the respective first and second thermal forming station is provided with a female moulding die (51,61). The female moulding die (51,61) is mounted on a pneumatic shaft (54,64) which is supported by a supporting frame (55,65). A conveyor (52,62) is attached to the outer side of the female moulding die (51,61) for receiving and loading of the finish plant fibre moulded article released from the male moulding die (32,42). The pneumatic shaft (54,64) is responsible for the reciprocating movement of the female moulding die (51, 61) and the conveyor (52,62) in a horizontal direction only.

Each of the platens (22,31, 41) on the respective chambers (21,30, 40) are associated with a vacuum system for adhering and releasing of the fibre moulded article from the respective dies (23,32, 42). Only platens (31, 41) on the respective first and second thermal forming station are provided with heating means for drying and hardening of the wet fibre moulded article form on the dies.

The manufacturing process of the plant fibre moulded article by using the present invention may now described as follows.

The plant fibres are first disintegrated by means of grinding, cutting, chopping or milling. The refined plant fibres are then added with water in a concentrating pond. Agitation is applied to the fibre-water mixture to ensure that the fibres are well dispersed in the water. Chemical pulp may be added to the mixture to increase the hardness of the fibre moulded product. The mixture is continuously agitated until all the added chemical pulp is dissolve and the fibres are uniformly disperse in the water. The fibre content of the mixture ranges from 5% to 80% by weight.

Next the mixture is transferred to a diluting pond whereby more water is added. Additives such as water resistant agent and oil resistant agent are added to the mixture to give a furnished slurry.

In the preferred embodiment of the present invention, the added additives are Food Graded since the plant fibre moulded products are use as food container. Continuous agitation is applied to the furnished slurry to ensure the added additives are uniformly dispersed among the refined fibres.

The slurry is diluted with water until the fibre content of the slurry ranges form 0.01% to 1.0% by weight.

The diluted plant fibre slurry is pump into the perforated moulding tool (5) which is mounted within the slurry tank (4) of the moulding station by using pumps and pipes. Vacuum is applied to the perforated moulding tool (5) to evacuate the water content of the fibre slurry and form a wet plant fibre moulded article on the filtering net.

At a stage after the wet plant fibre moulded article is formed, the pneumatic ram (24) lowered the upper vacuum platen (22) and the forming mould (23) to come into contact with the perforated moulding tool (5). At this stage the vacuum on the perforated moulding tool (5) is released and negative pressure is applied to the upper vacuum platen (22) to temporarily adhere the wet moulded article to the forming mould (23).

The upper vacuum platen (22) and the forming tool (23) are then elevated and return to its initial position. The lower thermal chamber (50) of the first thermal forming station which consists of female moulding die (51) and the conveyor (52) is travel horizontally to the lower end of the upper forming mould (23) on the moulding station. Then the pneumatic ram (24) of the moulding station lowered the upper forming mould (23) to come into contact with the female moulding die (51) of the first thermal forming station.

At this stage, positive pressure is applied to the upper forming mould (23) by vacuum means to release the wet moulded article from the forming mould (23) to the female moulding die (51). At the same time, vacuum is applied to the female moulding die (51) to temporarily adhere the wet moulded article. Once lower thermal chamber (50) is return to the thermal forming station, the pneumatic ram (24) of the moulding station is then lowered the upper vacuum platen (22) and the forming mould (23) to the slurry tank (4) to begin the subsequent moulding operation. The newly formed wet fibre moulded article is then transferred to the second thermal forming station.

In the first thermal forming station, the upper male moulding die (32) is lowered into contact with lower female moulding die (51). Heat and pressure is applied to the dies (32,51) so as to reduce the thickness and to dry the wet fibre moulded article.

After the thermal forming operation is completed, the male moulding die (32) carries the dried and finish moulded article is elevated whereas the lower thermal chamber (50) is travel horizontally until the conveyor (52) is align vertically at the bottom of the male moulding die (32). The dried and finish moulded article is then deposited on the conveyor (52). The releasing of the finish moulded article is effected by applying positive pressure to the male moulding die (32). The finished article is then sent off from the moulding machine (1) by the conveyor (52) after the lower thermal chamber (52) is return to its initial position. The dried moulded article may be subjected to post processing such as trimming and sterilization.

The same thermal forming operation is repeated in the second thermal forming station after the wet fibre moulded article is transferred from the moulding station to the second thermal forming station.

Thus, there has been disclosed herein an automatic device and manufacturing process of making moulded article from the plant fibre slurry. It will be apparent to those skilled in the art that various modifications and variation can be made in the system of the present invention without departing from the scope or spirit of the invention.