WO2009057162A1

WO2009057162A1 - System for making large objects from fibrous slurry

Info

Publication number: WO2009057162A1
Application number: PCT/IS2008/000018
Authority: WO
Inventors: R. Jonsson Friorik; Ari Friöriksson FRIÖRIK; Johann BJÖRGVINSSON; Arthur M. Shulenberger
Original assignee: Graenar Lausnir Ehf.
Priority date: 2007-10-31
Filing date: 2008-10-31
Publication date: 2009-05-07
Also published as: IS8688A; GB2468427A; IS2688B; RU2010121750A; GB201008990D0

Abstract

The present invention provides an apparatus and a method for making large objects from fibrous slurry or paper pulp in water by using mating molds and hot air drying. The apparatus and the method of the present invention use robots with 3-dimentional freedom of rotation to transfer moulds from slurry tanks for draining and to transport the objects to drying units. A set of robots with mating mold units handle the objects while being formed, dried and transported from the production station in a very effective manner.

Description

SYSTEM FOR MAKING LARGE OBJECTS FROM FIBROUS SLURRY

Field of invention

The present invention relates to an apparatus, a method and a system for forming large objects from fibrous slurry using robotics, moulds and vacuum technology.

Background of the invention

It is well known in the art to manufacture objects by vacuum moulding from slurry, such as paper pulp in water. Such methods and devices are focused on bringing the pulp into a mould, which is assembled from two or more components and can be opened for releasing the object from the mould. The mould is dipped into a pulp container and the pulp is drawn into the mould, usually by vacuum, such that the inner surface of the mould is covered with the pulp. The inner surface of the mould is perforated, which allows the water to penetrate through the surface of the mould leaving the fibrous material on the inside of the mould surface. Vacuum is applied for a certain amount of time to coat the mould with appropriate amount of pulp and then the mould is removed from the pulp container. Excess water is removed from the mould by vacum and wet press Then the object is removed from the mould for drying.

WO 2004/027154 discloses an apparatus for producing a molded pulp product from a fiber slurry. The apparatus has a dip tank for the fiber slurry and a porous mold on a platen, is carried by the platen. The mold is lowered into the fiber slurry in a downward direction and vacuum is supplied to the mold while the mold is disposed in the fiber slurry to cause fibers in the fiber slurry to collect onto the mold and form a wet molded pulp product. The mold with the wet molded product thereon are moved out of the fiber slurry through the liquid level to permit water to drain from the mold and the wet molded pulp product. The wet molded pulp product is then dried by hot air.

Summary of the invention

It is an object of the present invention to provide an apparatus, a method and a system for making large objects from fibrous slurry or paper pulp in water by using mating molds and hot air drying without deformation, distortion or discoloring like previous methods. The apparatus and the method of the present invention use robots with 3-dimentional freedom of rotation to transfer moulds from slurry tanks for draining and to transport the objects to drying units. The objects/items are formed from pulp in a time consuming and energy saving way by drying the object with hot compressed air on one side preventing the product from warping. A set of robots with mating mold units handle the objects while being formed, dried and transported from the production station in a very effective manner.

It is further an object of the present invention to provide a method for making objects from fibrous slurry/pulp using a moulding unit attached to a robotic arm. The pulp is drawn up into the mould by vacuum for a certain period of time and then the mould is removed from the slurry container. The perforated inner surface of the mould defines the outer shape of the object to be produced. Excess water is drained from the mould as the pulp pressed against a perforated inner surface of the mould by continued suction and rotation of the moulding unit on the robotic arm. The object can be dried further in the mould by pressing it against airtight elastic material, wet press, to further force out excess water from the object .

Description of the invention

In a first aspect of the present invention an apparatus is provided for forming large objects from fibrous slurry, such as paper mass slurry. The apparatus comprises a first robot having a first robotic arm and a first male moulding unit attached to the first robotic arm. The apparatus further comprises a second robot further also having a second robotic arm and a first female moulding unit attached to the second robotic arm. The first male and female moulding unit comprises moulding face, which forms the shape of the object to be produced by the apparatus. The moulding unit is attached to the free end of the robotic arm, and as the robotic arm has a 3-dimentional freedom of rotation, the moulding unit can be moved freely in all directions around the robot and released it self or release the object from the moulding unit. Air activating means is provided as part of the apparatus for applying air suction to the mould for obtaining of sufficient fibrous slurry onto the molding face and for releasing with compressed air, the object from the moulding unit. A fibrous slurry container is either attached to said apparatus or placed nearby so that the first robotic arm can place the first male moulding unit in the container and by vacuum suction cover the moulding face with fibrous slurry thereby forming the object and removing the moulding unit from the container. The apparatus also comprises a drying unit for drying the objects after being formed. The distance between the first and the second robot is such that the object can be transported from the first male moulding unit to the first female molding unit. The air activating means controls suction of fibrous slurry into the mould to determine the thickness of the layer collected onto the moulding face, transfers said object from said first male molding unit to said first female molding unit as well as transferring said object to a drying unit. Means for applying hot pressurized air flow through the object for drying the object is also provided.

In a second aspect of the present invention method is provided for forming a large object from fibrous slurry, the method comprises the following steps :

- a robotic arm places a first male moulding unit in the fluidic slurry container,

- applying air suction to first male moulding unit for obtaining of sufficient fibrous slurry onto the molding face, - forming the object,

- removing said first male moulding unit from the container,

- draining excess water from the mould and object by pressing it against airtight elastic material, wet press

- transferring the object from the first male moulding unit to the first female molding unit,

- transferring said to a drying unit, and

- applying hot pressurized air flow through the object for drying the object,

The method is characterized in that the air activating means controls releasing of the objects from the first male molding unit onto a female mold.

The following embodiments relate to both the apparatus and the method of the present invention.

In the present context the word robot is in accordance with the ISO 8373 word definition. "An automatically controlled, reprogrammable, multipurpose, manipulator programmable in three or more axes, which may be either, fixed in place or mobile for use in industrial automation applications." Similarly, in the present context the word arm is used to define the structure which can move in three dimensional space, extending from the robot's base member. Similarly, in the present context the word wrist is used to define the rotate-able structure which is attached to the end of the robot arm on one side, and which the end implement is attached to on the other side.

In an embodiment of the present invention the air activating means or the means for providing suction or air pressure for the apparatus and the method is selected from devices such as a vacuum pump.

In an embodiment of the present invention the drying unit has a receiving chamber for receiving the objects for drying. One important aspect of the present invention is that the objects are dried on moulding unit to preserve the shape of the object. In an embodiment of the present invention the chamber is can also be connected to a mean for passing hot pressurized air flow through second male mold for drying the object. The drying chamber has a closing means such as a lid or door to seal the chamber and apply hot dry air through the object as it is placed on the moulding unit. The advantage of this is that if the object is dried on the face of the moulding unit, it will not be deformed during drying. There can be one or more drying unit associated with each set up of a first and second robot, either arranged around the robots or on a continuous transfer means, such as a conveyor. The second robotic arm can then collect the object from the drying unit and place it on an out feed unit, such as a conveyor band.

In an embodiment of the present invention the second robot releases the first female moulding unit into the drying unit and the object is dried on said female moulding unit therein. Another possibility is where the second robot releases the object from said first female moulding unit onto a second male moulding unit positioned in the drying unit and the object is dried on said second male moulding unit.

In an embodiment of the present invention the inside of the mould, i.e. the moulding face is formed from a fluid permeable material. The moulding face defines the shape of the object to be produced, such as a pallet or a coffin and a matching lid for the coffin. The fluid permeable material can be selected from, but not limited to woven wire structures such as wire net and wire gauze.

In an embodiment of the present invention the device further comprises a washing means/device for washing the moulding unit after forming an object. In one embodiment the washing device is a separate container filled with fluid to rinse the mould after one round of objects has been produced. In another embodiment the washing device is a fluid dispersing device, which washes the mould by spraying the mould with fluid, such as water. After the objects have been released from the moulds, the robotic arm places the moulding unit into a cleaning tank and introduces water or other cleaning ageing into the moulds and the moulding unit to clean remaining fibers from the moulds. Water can be introduced and released from the moulding unit several times to clean the moulding unit. The moulding unit can also be cleaned with a spraying means.

The apparatus can be used with the method of the present invention to manufacture all large size articles or objects, such as pallets, packaging containers, coffins, stretchers, body bag/box, and furniture.

The air activating means of the present invention has the function of providing suction force to the moulds to draw paper pulp/fibrous slurry into the mould through an inlet in the moulding unit. The inlet of the moulding iinit can also be connected to a device for provident hot pressurized are through the moulding face for drying the object being formed. The air activating means also provides air to move the object in the mould and to control the releasing of the object from the mould.

Detailed description of the invention

Illustrative embodiments of the invention will be described more in detail with reference to the drawing.

List of drawings FIG. 1 is an overview of the apparatus of the present invention of forming an object and transfer of object into a drying chamber.

FIG. 2 shows the apparatus when transferring the object from one robot to another.

Figures 1 and 2 show the apparatus of the present invention in operation, where pallets are being formed by two robots, six drying chambers and one forming tank. The apparatus is shown on a frame with a forming tank, where the pulp is mixed and obtained from. The first robotic (forming robot) has a male molding unit mounted on the robotic arm. The forming robot places a first male moulding unit in the fluidic slurry container and suction is applied through a vacuum pump. The molding face is covered with pulp and the thickness of the cover is determined by the duration of suction of pulp. (FIG. 1 ) The forming robot removes the male mold from the forming tank (pulp container) and transfers the object from the male moulding unit (forming mould) to a mating mold (female moulding unit) mounted on the transfer robot. (FIG.2). The transfer robot then transfers the female moulding unit now containing the object to the drying chamber. The object is released and received from one mould to the other by using the air activating means to blow the object from one mould, whereas the other mould receives the object by applying suction to the moulding face. When the door of the drying chamber opens the female moulding unit can be placed in the chamber and then the door is closed. After the door is closed, hot air is guided from one side of the object through the object and the male mould to dry the object. The transfer arm can now obtain a moulding unit from a different drying chamber, where the object is dry, move the moulding unit over a takeaway conveyor and release the object onto the conveyor belt (not shown). Then the transfer robot can move the empty female mould towards the forming robot and receive a newly formed object from the male moulding unit.

Claims

1. Apparatus for forming large objects from a fibrous slurry, the apparatus comprising:

- a first robot further comprising, o a first robotic arm, o a first male moulding unit

- a second robot further comprising, o a second robotic arm, o a first female moulding unit

- air activating means,

- fibrous slurry container, and

- drying unit,

wherein the first male and female moulding unit comprise moulding face, said moulding unit being attached to the free end of the robotic arm, the robotic arm having a 3-dimentional freedom of rotation, and said robotic arm placing first male moulding unit in the container,

- applying air suction to the mould for obtaining of sufficient fibrous slurry onto . the molding face,

- forming the object,

- removing the same from the container,

- pressing the object against airtight elastic material applying air suction to the mould

- transporting the object from the first male moulding unit to the first female molding unit,

characterized in that the air activating means controls suction of fibrous slurry into the mould and onto said moulding face, and transfers said object from said first male molding unit to said first female molding unit,

- transferring said object to a drying unit,

- applying hot pressurized air flow through the object for drying the object.

2. An apparatus according to claim 1 , wherein drying unit has a receiving chamber for receiving the first female moulding unit.

3. An apparatus according to claim 1 , wherein the chamber of the drying unit comprises a second male moulding unit for receiving the object from said first female moulding unit.

4. An apparatus according to claims 1-3, wherein the chamber is connected to a mean for passing hot pressurized air flow through the object and second male mold for drying the object.

5. An apparatus according to any of the reseeding claims, wherein the air activating means comprises a vacuum pump.

6. An apparatus according to any of the reseeding claims, wherein the moulding units comprise a moulding face for forming the object.

7. An apparatus according to claim 6, wherein the moulding face comprises a fluid permeable material.

8. An apparatus according to claim 1 , further comprising a washing means for washing the moulding unit after forming an object.

9. A method for forming a large object from fibrous slurry, the method comprising:

- applying air suction to first male moulding unit for obtaining of sufficient fibrous slurry onto the molding face,

- forming the object,

- removing said first male moulding unit from the container, - draining excess water from the mould,

- transferring the object from the first male moulding unit to the first female molding unit, - transferring said to a drying unit, and

- applying hot pressurized air flow through the object for drying the object, characterized in that the air activating means controls releasing of the objects from the first male molding unit onto a female mold.

10. The method according to claim 9, characterized in that the second robot releases the first female moulding unit into the drying unit and the object is dried on said female moulding unit.

11. The method according to claim 9, characterized in that the second robot releases the object from said first female moulding unit onto a second male moulding unit positioned in the drying unit and the object is dried on said second male moulding unit.

12. The method according to claims 9-11 , characterized in that the second robotic arm retrieves the object from the drying unit and places the object on an out feed unit.