GB2331040A

GB2331040A - Porous mould for forming fibre products

Info

Publication number: GB2331040A
Application number: GB9819464A
Authority: GB
Inventors: Duncan Hamilton Stewart
Original assignee: UNIVERSAL PULP PACKAGING Ltd
Current assignee: UNIVERSAL PULP PACKAGING Ltd
Priority date: 1997-11-05
Filing date: 1998-09-08
Publication date: 1999-05-12
Also published as: GB9819464D0

Abstract

A mould 10 for forming fibre product, such as paper, is made of a porous material through which air and water may pass. The porous material may be formed of sand or ceramic beads together with plastic resins or cement binders. Ahernatively the porous material may be formed of plastic resins together with porosity-inducing additives. The mould may be formed by casting or by machining form a solid block of porous material. Preferably the porous material has a surface which does not stick to the fibres.

Description

"Mould for Forming Fibre Products" The present invention relates to a mould for forming products form fibrous materials such as paper.

Conventional methods for producing moulds for forming fibre products have consisted of a solid mould formed in the desired shape. This mould is then drilled with ventilation holes approximately 10 to 12 mm apart.

This solid mould is then covered with a carefully formed wire gauze. A aqueous suspension of paper fibres is then sucked onto the solid mould by suction through the drilled holes. The fibres are then retained by the wire gauze whilst the rest of the water in which the fibres were suspended in is drained away.

The formed product can be removed from the mould in a wet condition or dried in place.

Disadvantages of this type of mould include the following. The drilling of the holes in the solid mould is time consuming and could damage the mould.

The wire gauze required must be carefully formed which is also time consuming and could lead to inconsistency when the wire gauze is replaced, as the form of each new wire gauze may not be exactly the same as the previous.

It is an object of the present invention to obviate or mitigate the above disadvantages.

According to the present invention there is provided a mould for forming fibre products, said mould being formed of a porous material through which air and water may pass.

Preferably, said porous material has a surface which does not stick to the fibres.

Preferably, said porous material is formed of sand or ceramic beads with plastic resin or cement binders.

Alternatively, said porous material may be formed of plastic resins with additives which induce porosity.

The mould may be formed in the required shape either by casting into a shaped pattern or by machining from a solid block of porous material.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Fig 1 is a cross sectional view of a porous mould.

Fig 2 is a plan view from above of the porous mould of Fig 1.

Referring to the drawings, Fig 1 shows a porous mould 10. Said porous mould has an upper section 13 and a lower section 14. Said porous mould 10 has a lower protrusion 11 being formed on the lower section 14 of the porous mould 10 and being produced to define the shape of the finished fibre product. Said upper surface 13A is placed adjacent a vacuumed area 15 and said lower surface 14A is placed adjacent a flow of paper fibre in aqueous suspension. The vacuumed area 15 causes the aqueous suspension of paper fibre, flowing adjacent to the lower surface 14A of the porous mould 10, to be evenly sucked onto the lower surface 14A of the porous mould 10. The paper fibre is evenly sucked onto the lower surface 14A by means of an upper indent 12 corresponding to the lower protrusion, designed to provide the mould with uniform pressure across the lower surface 14A. The water is then sucked out of the aqueous suspension of paper fibre allowing the paper fibre moulded product to be deposited on the lower surface 14A of the porous mould 10.

Whilst still wet, the paper fibre moulded product is discharged from the mould then dried.

This technique lends itself to allowing the mould to be tailored to allow different pressures across the lower surface 14A. This allows the thickness of the fibre product to be varied across the mould if so desired.

Modifications and improvements may be made to the foregoing within the scope of the present invention.

Claims

CLAIMS 1. A mould for forming fibre products, said mould being formed of a porous material through which air and water may pass.
2. A mould as claimed in Claim 1, wherein said porous material has a surface which does not stick to the fibres.
3. A mould as claimed in either preceding Claim, wherein said porous material is formed of sand or ceramic beads with plastic resin or cement binders.
4. A mould as claimed in any preceding Claim, wherein said porous material is formed of plastic resins with additives which induce porosity.
5. A mould as claimed in any preceding Claim, wherein the mould is formed in the required shape either by casting into a shaped pattern or by machining from a solid block of porous material.
6. A mould for forming fibre products, substantially as hereinbefore described with reference to the accompanying drawings.