AU613104B2

AU613104B2 - Manufacturing of bricks

Info

Publication number: AU613104B2
Application number: AU24762/88A
Authority: AU
Inventors: Jamie Pearson
Original assignee: Brickworks Ltd
Current assignee: Brickworks Ltd
Priority date: 1987-11-06
Filing date: 1988-11-04
Publication date: 1991-07-25
Anticipated expiration: 2008-11-04
Also published as: AU2476288A

Description

-I i; 6 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE 1310 Form Short Title: Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: BRICKWORKS LIMITED Address of Applicant: Wallgrove Road, Horsley Park, NSW 2164

AUSTRALIA

Actual Inventor: MR. JAMIE PEARSON Address for Service: GRIFFITH HACK CO.

71 YORK STREET SYDNEY NSW 2000

AUSTRALIA

Complete Specification for the invention entitled: "MANUFACTURING OF BRICKS" The following statement is a full description of this invention, including the best method of performing it known to me/us:- S03420 04/ 1 /88 2012G/ELM The present invention relates to manufacturing bricks, and more particularly concerns clay based bricks where the brick is formed from a mixture of relatively fine clay-like particles together with relatively coarse particles and then fired to provide a rigid and hard structure. However, the term "brick" used in this specification is not to be construed as limited to conventional housebuilding brick but extends to any other generally similar building elements which may be used for structural and/or decorative purposes.

Conventional brick manufacture usually comprises preparing a plastic mixture of clay and relatively coarse particles such as shale and other solids mixed with water. The other solids can include grog (which means ground-up defective bricks) as well as frit (which forms glassy-like spots and colourations in the brick structure) and other mineral particles. Usually the maximum particle size is of the order of 1/8 inch or 3 mm. diameter. This plastic mixture is then formed into the desired brick shape, it is dried and the baked at temperatures up to 1100 0 C. Traditionally, bricks are formed in a mould and are known as "dry pressed ?ricks" but an alternative modern alternative is extruded bricks.

In order to provide a range of choice for customers, bricks are formed in a variety of colours and surface finishes and after the initial formation of the brick, but before the drying and firing process, the bricks may be given a surface treatment by the application of colouring agents, frit or the like. Usually, this surface finish is applied, in the case of a conventional house brick, to one elongated side face and the two end faces only.

The present invention is directed to providing new and useful alternatives in the formation of clay bricks to provide an attractive surface finish.

5560S/ELM 2

JI

In one aspect, the invention consists in a method of forming a building brick comprising forming a brick-shaped block from a plastic mixture of clay-like particles and relatively coarse particles, subjecting at least a portion of the surface of said block to a liquid spray which washes away components of the clay-like particles from the treated surface, thereby leaving a pitted finish with the coarse particles protruding from the surface, and subjecting the block to a firing process to produce a hard block.

In another aspect, the invention extends to a building brick produced by the above-described method.

The use of the invention permits an aged or weathered appearance to be provided in a new brick which, nevertheless, can be produced in a cost effective manner and have substantially undiminished load-bearing properties.

Furthermore, the brick can have the hardness and structure which is achieved by modern brick manufacturing techniques, yet can have an appearance somewhat similar to very old handmade bricks which are often known as "sandstock" bricks. However, the invention may also be used in combination with existing surface treatments to enhance the appearance gained. These existing surface treatments include using indent rollers, slurries, low vacuum, wire cut, smooth skin and scratched surface treatments.

In a preferred embodiment, the liquid spray is an aggressive water spray comprising a multiplicity of jets. The water runs off the brick surface carrying with it the clay fragments and at most a small proportion of the coarse particles; this produces a slurry which is collected and pumped back to the initial solid mixing stage of the process in which a plastic mixture of clay particles and coarse particles is formed.

Preferably, the water jet at any instant impinges only upon a small proportion of an exposed face of the brick, relative ,movement between the brick and the jet being provided. This

'/KLS

3 relative movement can be achieved simply by providing a fixed fan-like nozzle in the spray equipment and moving the bricks on a conveyor past the nozzle. Alternatively, an oscillating or rotating nozzle can be used.

In a preferred embodiment, the bricks are advanced 3 successively along a conveyor which passes through a spray hood with one long face of the brick uppermost and the water spray is directed onto the upper face of the brick and the two side faces. Preferably, on the upper side, a rotating nozzle is used to cause a somewhat random-like etching of the brick surface to produce deeper pits in some portions of the face than others and fixed nozzles are used on the side faces. The use of a rotating nozzle on the upper face can facilitate washing away of the clay particles in a slurry off the horizontal head of the brick.

rAlthough the process can be applied to dry pressed bricks, most advantageously the process can be applied to a relatively high speed, efficient extruded brick line. In S 20 such a system, the extruder produces a rectangular cross-section extruded plastic mass known as a 'slug' and, preferably, it is the upper and side surfaces of this slug which are treated by the water spray before division of the slug into individual bricks in a cutting process. Typically 25 40 bricks are cut from each slug. Alternatively, prior to 9n being cut, the slug may be further treated by having various coating agents applied to the surface of the slug.

Embodiments of the invention could also be applied to individual bricks moving along a conveyor either after an extrusion process or a dry pressing process and furthermore, the bricks could be treated if desired after the initial drying process which precedes the firing process in a kiln.

By way of example and embodiment of the invention will now be described with reference to the accompanying drawing which is a schematic cross section through a treatment 5560S/ELM 4 station embodying th The illustrated emboc extruded brick mater: Ji 5 11 and through a met.

station. Fixed fan sides of the hood an( pressure water suppli nozzle 15 connected centrally within the high velocity, high face of the slug 10.

adjustment towards ai respective angles re: can also be adjusted surface texture of t the nozzles 13 and i! or fixed as may be d An air blast is prov: downstream of the no; clay slurry from the draining down throug The slurry may incori material. The slurr pipe 21 into a recir( slurry along pipe 23 brick manufacturing I After the slug has cc e present invention.

diment is applied to a slug 10 of ial which is advanced along a conveyor al hood 12 which surrounds a water spray shaped nozzles 13 extend through the d are connected to respective high y tubes 14 whereas a rotating fan-shaped to water supply tube 16 is provided top region of the hood so as to spray a pressure jet of water onto the upper Each of the nozzles is capable of nd away from the slug surface and their lative to the confronting slug surface so that the desired effect on the he slug can be achieved. Furthermore, 5 can be altered so as to be oscillating esired.

ided through air tubes 17 immediately zzles 13 and 15 to remove the aqueous surfaces of the slug, the slurry h a discharge funnel 18 into a sump 19.

porate some minor coarse aggregate 20 is arranged to be pumped through a ,ulation pump 22 which discharges the for reuse in the initial stage of the process.

)mpletely emerged from hood 12, it is advanced to a receiving station at which the slug, in a conventional manner, is divided to form discrete bricks which are then dried and fired. Alternatively, prior to slug being divided, it may be coated with various coating agents including sawdust, gravel, scoria, frit, sands, oxides, colouring agents, engobes, glazes and slurries.

:he 5560S/ELM 5

Claims

1. A method of forming a building brick comprising forming a brick-shaped block from a plastic mixture of clay-like particles and relatively coarse particles, subjecting at least a portion of the surface of said block to a liquid spray which washes away components of the clay-like particles from the treated surface, thereby leaving a pitted finish with the coarse particles protruding from the surface, and subjecting the block to a firing process to produce a hard block.

2. A method as claimed in claim 1 and wherein the liquid spray is a high pressure fine water spray provided by a plurality of nozzles.

3. A method as claimed in claim 2 and wherein the water spray is arranged at any instance to impinge only upon a small proportion of the exposed surface of the block.

4. A method as claimed in claim 3 wherein at least one of said nozzles is a rotating nozzle providing a fan-shaped jet.

A method as claimed in any one of the preceding claims wherein the liquid spray is provided through a plurality of nozzles, at least one of which is arranged to oscillate.

6. A method as claimed in any one of the preceding claims and applied to treatment of an extruded slug for use in forming house bricks, the liquid spray being provided through a plurality of nozzles with at least one nozzle directed towards the upper face of the slug and arranged to rotate about a substantially vertical axis over the slug, and the slug being moved on a conveyor past the nozzle.

7. A method as claimed in any one of the preceding claims and including an air jet adjacent to the liquid spray to Sg /KLS 6 !T I remove, in a slurry form, clay particles and the liquid used in the spray.

8. A method as claimed in any one of the preceding claims wherein at least one coating agent is applied to the treated surface prior to subjecting the block to the firing process to produce a hard block.

9. A building brick produced by the method as claimed in any one of the preceding claims. DATED this 4th day of January 1991 BRICKWORKS LIMITED By their Patent Attoneys GRIFFITH HACK CO. f¢ C CC -7