IES960046A2 - "A manufacturing process" - Google Patents

Abstract

Shale is broken in a crusher (11) and delivered to a box feeder (12). The shale is discharged from the box feeder (12) to a pan mill (18) in which the size of shale pieces is reduced prior to delivery between high-speed rollers (26) for final size reduction. Downstream of the rollers (26) a feeder (30) delivers the shale pieces to a mixer (34) in which water is added to form a shale paste. The shale paste is passed through an extruder (124) from which a strip (123) of material is extruded. The strip (123) is cut into tiles 129 which are delivered to a drying room (70). Heated air extracted from a kiln (75) after firing is passed through the drying room (70) to reduce the moisture content of the tiles. Then the dried tiles are delivered to a kiln (75) and fired. <Fig. 1>.

Description

A Manufacturing Process s 96 0 04 6 This invention relates to a manufacturing process and apparatus, in particular for manufacturing ceramic tiles.

The invention particularly relates to a process and apparatus for manufacturing ceramic tiles in an efficient and trouble-free manner.

According to the invention there is provided a manufacturing process for ceramic tiles comprising the steps: delivering shale to a crusher, crushing the shale into pieces and conveying the broken shale pieces to a feeder, discharging the broken shale pieces from the feeder at a pre-desired rate, delivering the broken shale pieces to a pan mill having a tray for receiving the broken shale pieces, circulating rollers around the tray for crushing the shale pieces through discharge slots in the tray for reducing the size of the shale pieces, feeding the crushed shale pieces in a controlled manner between a pair of high-speed rollers for further reducing the shale pieces to a pre-desired maximum size, delivering the shale pieces to a mixer, OPEN TO PUBLIC INSPECTION UNCI K SECTION 28 AND RULE 23 JNL ΝΟ..ΛΤ.82,.......OF k 96 90 4 β - 2 adding water to the shale in the mixer and mixing the water and shale to form a shale paste having a desired water content, delivering the shale paste to an extruder, forcing the shale paste through a die at an outlet of the extruder for forming a strip of shale paste of a desired shape, cutting a length of material from a free end of the strip, delivering the length of material to a tile former, cutting the length of material into individual tiles of a pre-desired size in the tile former, delivering the tiles the drying room and circulating heated air through the drying room for reducing the moisture content of the tiles to a pre-set desirable maximum value, the heated air being delivered to the drying room from a kiln after firing of the kiln has been completed, conveying the dried tiles to a kiln, sealing the kiln and firing the kiln, after firing removing the tiles from the kiln.

In one embodiment of the invention the process includes cutting the length of material in the former by aligning the length of material with a set of spaced-apart cutter wires, pushing the length of material through the cutter wires for separating the length of material into a plurality of tiles of a pre-desired size.

In one embodiment of the invention the process includes alternating feeding of the shale pieces between a central »96004 6 portion of the high-speed rollers and outer ends of the rollers .

In a particularly preferred embodiment the process includes feeding the heated air from the kiln to a distribution manifold beneath the floor of the drying room and discharging the heated air up through a slatted floor of the drying room for drying the tiles.

Conveniently the process includes the step of conveying the broken shale from the feeder to the pan mill, passing the broken shale beneath a magnetic plate extending above the conveyor upstream of the pan mill.

In a further embodiment the process includes delivering shale pieces discharged from the high-speed rollers to a mixer feeder, the mixer feeder having a hopper for reception of the shale pieces with discharge screws at an outlet of the hopper for discharging the shale pieces from the hopper, controlling the speed of the discharge screws for regulating discharging of shale pieces from the hopper to the mixer.

In another embodiment the process includes forcing the shale paste through a plurality of holes in a discharge plate of the mixer for forming the shale paste into pellets of shale paste at an outlet of the mixer.

In another aspect the invention provides apparatus for carrying out the process of the invention as herein described.

The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which; - 4 LMH44 Fig. 1 is a schematic illustration of a tile manufacturing process according to the invention; Fig. 2 is a diagrammatic perspective view of high speed rollers used in the process; Fig. 3 is a plan view of the rollers; Fig. 4 is a perspective view of a mixer used in the process .

Fig. 5 is a schematic perspective view of tile forming apparatus used in the process.

Referring to the drawings, a process and apparatus for manufacturing ceramic tiles according to the invention will be described.

Shale is delivered from a shale pit 10 to a crusher 11 and fed through an associated pair of contra-rotating crushing rollers to break up the shale. The broken shale is delivered downstream to a box feeder 12. The shale is discharged from an outlet 14 of the box feeder 12 at a desired rate and is delivered on a conveyor 15 under a magnetic plate 16 which removes any iron or steel particles entrained in the shale.

The shale is then delivered into a pan mill 18 having a tray 19 over which a pair of rollers 20 circulate, the rollers 20 being mounted on a rotating carrier arm 21. The rollers 20 press the shale down through slots in the tray 19 of the pan mill 18 reducing the size of shale pieces to 6mm maximum, the pieces dropping onto a conveyor 24 which delivers the shale to high speed rollers 26. If desired water may be added to the shale in the pan mill. ' 96 00 4 β Shale is delivered between an associated pair of high speed rollers 26 for reduction of the shale particles to 0.6mm (0.025 inch) size maximum. It will be noted from Figs. 2 and 3 that a spreader bar 28 is positioned above the high speed rollers 26 and is movable between a lowered position as shown in Fig. 2 and a raised inoperative position as shown in broken outline in Fig. 2. In the lowered position the bar 28 deflects the shale outwardly to outside edges of the rollers 26. With the bar 28 in the raised inoperative position the shale will tend to feed into the centre portion of the rollers 26. By engagement and disengagement of the bar 28 on successive days this ensures an even wearing of the surface of the rollers 26 which advantageously gives more accurate crushing of the shale and also reduces the need for periodic dressing and resurfacing of the rollers 26.

The shale discharged from the rollers 26 is conveyed to a feeder 30 which comprises a hopper with discharge screws at an outlet of the hopper for discharging the shale at a desired rate from the hopper. The speed of the screws is adjustable for controlling the discharge rate.

Operation of the various machines is regulated by a controller which is operable to regulate the speeds of the various machines to achieve a smooth flow of shale material at a desired rate to the feeder.

Downstream of the feeder 30 the shale is delivered by a conveyor 32 into a mixer 34. The mixer 34 comprises a container 35 within which a pair of juxtaposed mixing paddles 36 are rotably mounted for mixing the shale with water delivered through a sptay head 38 into the mixer 34. As the paddles 36 mix the shale and water they advance the mixture to an outlet end 39 of the mixer 34 formed by a ^•60046 - 6 plate having a plurality of through holes 40 through which the shale mixture is delivered to form pellets which drop on to a conveyor 42.

Downstream of the mixer 34 the shale pellets are delivered by a conveyor 121 into a hopper 122.

Referring to Fig. 5 shale is delivered from the mixer 34 by a conveyor 121 into a hopper 122. At a lower end of the hopper 122 a screw extrudes a flat strip 123 of shale paste through a die 124. The strip 123 is carried on a conveyor 124a to a cutter 125 which cuts the strip 123 into lengths 126 of a desired size which is for example 900mm lengths. The length 126 is fed into a tile former 127 in which a pusher bar (not shown) pushes the lengths 126 outwardly through cutter wires 128 to form in this case three tiles 129 of approximately 300mm size. The tiles 129 are stacked on pallets and delivered to drying rooms 7 0.

Each drying room 70 has a slatted floor 71. Hot gases from kilns 75 are delivered through pipes for discharge up through the slots 72 in the floor 71 for drying the tiles 129 on the pallets within the drying room 70. Within the drying room 70 the moisture content of the tiles 129 is reduced to a maximum of 1.5%. It will be appreciated that waste heat from the kilns is used to dry tiles prior to firing thus minimising production costs and improving the overall efficiency of the process.

After drying the pallets 66 of tiles 129 are transported to a kiln 75 and the tiles 129 are stacked within the kiln 75 which is closed and fired. After firing the hot gases within the kiln 75 are bled off through the drying room 70 for drying further batches of tiles 129 and then the kiln έ 9600 46 - 7 75 is opened and the fired tiles 129 removed and palletised.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims (5)

1. A manufacturing process for ceramic tiles comprising the steps: delivering shale to a crusher, crushing the 5 shale into pieces and conveying the broken shale pieces to a feeder, discharging the broken shale pieces from the feeder at a pre-desired rate, delivering the broken shale pieces to a pan 10 mill having a tray for receiving the broken shale pieces, circulating rollers around the tray for crushing the shale pieces through discharge slots in the tray for reducing the size of 15 the shale pieces, feeding the crushed shale pieces in a controlled manner between a pair of highspeed rollers for further reducing the shale pieces to a pre-desired maximum size, 20 delivering the shale pieces to a mixer, adding water to the shale in the mixer and mixing the water and shale to form a shale paste having a desired water content, delivering the shale paste to an extruder, 25 forcing the shale paste through a die at an outlet of the extruder for forming a strip of shale paste of a desired shape, - 9 »60046 cutting a length of material from a free end of the strip, delivering the length of material to a tile former, 5 cutting the length of material into individual tiles of a pre-desired size in a tile former, delivering the tiles to a drying room, closing the drying room and circulating 10 heated air through the drying room for reducing the moisture content of the tiles to a pre-set desirable maximum value, the heated air being delivered to the drying room from a kiln after firing of the kiln has been 15 completed, conveying the dried tiles to a kiln, sealing the kiln and firing the kiln, after firing removing the tiles from the kiln.

2. A process as claimed in claim 1 which includes 20 cutting the length of material in the former by aligning the length of material with a set of spaced-apart cutter wires, pushing the length of material through the cutter wires for separating the length of material into a plurality of tiles 25 of a pre-desired size. A process as claimed in claim 1 or 2, which includes alternating feeding of the shale pieces between a central portion of the high-speed rollers and outer ends of the rollers, and 96004« - 10 preferably the process includes feeding the heated air from the kiln to a distribution manifold beneath the floor of the drying room and discharging the heated air up through a slatted 5 floor of the drying room for drying the tiles and preferably delivering shale pieces discharged from the high-speed rollers to a mixer feeder, the mixer feeder having a hopper for reception of the shale pieces with discharge screws at an outlet of 10 the hopper for discharging the shale pieces from the hopper, controlling the speed of the discharge screws for regulating discharge of shale pieces from the hopper to the mixer and preferably forcing the shale paste through a plurality of 15 holes in a discharge plate of the mixer for forming the shale paste into pellets of shale paste at an outlet of the mixer.

3. 4. A tile manufacturing process substantially as hereinbefore described with reference to the 20 accompanying drawings.

4.

5. A ceramic tile whenever produced according to the process as claimed in any preceding claim.