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WO1994011321A1 - Fabrication de tuiles de toiture - Google Patents

Fabrication de tuiles de toiture Download PDF

Info

Publication number
WO1994011321A1
WO1994011321A1 PCT/EP1993/003173 EP9303173W WO9411321A1 WO 1994011321 A1 WO1994011321 A1 WO 1994011321A1 EP 9303173 W EP9303173 W EP 9303173W WO 9411321 A1 WO9411321 A1 WO 9411321A1
Authority
WO
WIPO (PCT)
Prior art keywords
kiln
tiles
fired
zone
successively
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP1993/003173
Other languages
English (en)
Inventor
Lewis Graham Sharp
Neil Anthony Hart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Redland Technology Ltd
Monier Braas Research and Development Ltd
Original Assignee
Redland Technology Ltd
Redland Technologies Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Redland Technology Ltd, Redland Technologies Ltd filed Critical Redland Technology Ltd
Priority to AU55625/94A priority Critical patent/AU5562594A/en
Publication of WO1994011321A1 publication Critical patent/WO1994011321A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/0021—Charging; Discharging; Manipulation of charge of ceramic ware
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
    • B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/32—Burning methods
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path
    • F27B9/26—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path on or in trucks, sleds, or containers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D2003/0034—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities
    • F27D2003/0059—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities comprising tracks, e.g. rails and wagon
    • F27D2003/006—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities comprising tracks, e.g. rails and wagon with a return track
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/12—Travelling or movable supports or containers for the charge
    • F27D2003/124—Sleds; Transport supports
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D5/00—Supports, screens or the like for the charge within the furnace
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27M—INDEXING SCHEME RELATING TO ASPECTS OF THE CHARGES OR FURNACES, KILNS, OVENS OR RETORTS
    • F27M2001/00—Composition, conformation or state of the charge
    • F27M2001/15—Composition, conformation or state of the charge characterised by the form of the articles
    • F27M2001/1504—Ceramic articles
    • F27M2001/1508—Articles of relatively small dimensions
    • F27M2001/1517—Tiles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27M—INDEXING SCHEME RELATING TO ASPECTS OF THE CHARGES OR FURNACES, KILNS, OVENS OR RETORTS
    • F27M2002/00—Disposition of the charge
    • F27M2002/01—Disposition of the charge in one layer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/60—Production of ceramic materials or ceramic elements, e.g. substitution of clay or shale by alternative raw materials, e.g. ashes

Definitions

  • This invention is concerned with improvements in or relating to the manufacture of rocf tiles and is particularly concerned with a novel process and a novel kiln for use in the manufacture of clay roof tiles.
  • clay where used herein, it is meant “clay” as won from a clay-pit which clay generally comprises a “clay mineral” fraction and a “non-clay” fraction, the definition also extend ⁇ ing to modified clays, that is, “clay” as won to which or from which proportions of "clay minerals” and/or non-clay fractions have been added or removed.
  • kiln a one-high, counter ⁇ flow, continuous kiln comprised of heating, firing and cooling zones into which kiln products to be fired, i.e. "green state” clay roof tiles are introduced one at a time to be successively subjected to the heating, firing and cooling effects thereof wherein the air-flow is through the length of the kiln, or sub ⁇ stantially so, from an outlet end to an inlet end thereof and the kiln is operated continuously while products are fed there ⁇ through.
  • product By “green state” roof tiles, “partly fired” roof tiles, and “fired” roof tiles during their transit through the kiln of the present invention.
  • green state in reference to clay tiles it is meant freshly moulded tiles which are still wet and such tiles which have been dried, or substantially so, wherein the temperatures of the dried tiles are at ambient temperature or at temperatures up to 200 C C.
  • roof tiles where used herein, it is meant tiles which have been raised to and are being maintained at their “peak firing temperature”.
  • fired roof tiles where used herein, it is meant tiles which have been subjected to their “peak firing” temperature and are in the process of being cooled to ambient temperature or have been so cooled.
  • peak firing temperature is meant that temperature to which a product must be raised for “vitrification” thereof to be effected.
  • vitrification where used herein, it is meant the develop ⁇ ment of a microstructure necessary for the end product, i.e. a fired clay roof tile, to possess adequate properties, e.g. weather resistance, for purpose.
  • rock flour any hard rock which can be comminuted to an acceptable size, viz., substan ⁇ tially all of which is less than 200 microns and having a median particle size of between 20 and 60 microns and which, when fired, will not fail due to bloating, swelling, cracking or delamination as a result of, amongst other things, the evolution of gases which cannot escape from the matrix during firing.
  • Clay roof tiles are produced by very many methods in a multi ⁇ plicity of kiln structures from innumerable clay or clay-like compositions.
  • merchantable products were produced from locally won clays at acceptable energy consumption rates, it is now essential that in order to conserve clay deposits and to restrict the depletion of fuel reserves, clay roof tile production methods and kilns therefor have to be energy efficient.
  • kilns have become more sophisticated leading to a uniformity of product from virgin clays or clays comprising, in admixture, clays from various sources.
  • This phenomenon is not a mere happenstance; it is an occurrence which results from the inability of the unsophisticated clay compositions normally used for conventionally fired clay roof tiles to stand up to rapid increase of the kiln temperature from ambient temperature or substantially so to the firing tempera ⁇ ture of 800 to 1200°C.
  • GB 1489021 it is disclosed that, for a floor or wall tile of some 4-5 mm in thickness manufac ⁇ tured from a triaxial composition of clay, talcum and wollas- tonite, heating the products would be effected in 4 to 6 minutes, firing the products would be effected in 11 to 15 minutes and cooling down of the products to ambient temperature would take some 8 to 10 minutes.
  • the disclosure goes on to instruct that tiles of up to 10 mm would require longer heating and firing times of some 6 to 8 and 17 to 20 minutes respectively and if cooling times are extra ⁇ polated from those given for a 4-5 mm product, it is obvious that a total process time exceeds 36 minutes for the 10 mm product.
  • the clay roof tiles provided by the present invention typically have thickness in section in excess of 14 mm for plain tiles, i.e. a beaver-tail tile or similar product, and from 15 to 30 mm in section for contoured interlocking tiles, i.e. a double roman tile or similar product.
  • roller hearth kiln which operates as a "counterflow" vessel in which cooling and heating gases are caused to flow as between outlet and inlet ends respectively, i.e. in the opposite direction to that of the products, i.e. the wall and floor tiles, passing through the kiln. It will readily be appreciated that there are no diffi ⁇ culties in conveying planar wall and floor tiles through a roller hearth kiln.
  • plain tiles with hanging nibs and contoured interlocking tiles each require setters or cassettes to assist in their passage through a roller hearth kiln and to ensure that the upper surface, that is the surface of the tile which is uppermost in use, is not damaged by engagement with the rollers.
  • This requirement for setters may double the energy requirements of such kilns.
  • the present invention provides a process for the manufacture of clay roof tiles in a one-high, counterflow, continuous kiln as hereinbefore defined wherein the process comprises the steps of :
  • the invention still further provides a process for the firing of clay roof tiles comprising the steps of :
  • the invention also provides a process for the manufacture o clay roof tiles in a one-high, continuous, substantiall counterflow kiln as hereinbefore described wherein the composi tion for the tiles comprises :
  • composition for the tiles may comprise:
  • the particle size of at least 95% of the composition being less than 150 microns with a median particle size of 40 to 50 microns.
  • the "green state” tiles are raised, i.e. heated, to their "peak firing temperature” in 7 to 12 minutes and more especially in less than 8 minutes.
  • the “partly fired” tiles may be conveniently maintained at their "peak firing temperature” for between 4 and 8 minutes and more especially for less than 6 minutes.
  • the invention also provides a process wherein the "fired" tiles are subjected to a diminishing temperature gradient for not more than 22 minutes and more especially not more than 18 minutes.
  • the invention further provides a process for the manufacture of clay roof tiles in a one-high, continuous, substantially counterflow kiln as hereinbefore described wherein the composition for the tiles comprises : i) between 60 and 100 parts by weight of clay, and ii) between 0 and 40% by weight of rock flour wherein the composition has a particle size of less than 150 microns, or substantially so, with a median particle size of between 40 to 50 microns; wherein said process comprises the steps of:
  • the "peak firing temperature" of the composition from which the tiles are to be made may conveniently be between 900°C to 1250°C and preferably the “peak firing temperature” is between 1050°C and 1150°C and the energy required to fire a tile is between 1.5 and 3.5 MJ/kg of tile weight and more especially less than 2.5 MJ/kg of tile weight.
  • the invention also conveniently provides a counterflow, continu ⁇ ous kiln as hereinbefore defined comprising :
  • said kiln being a sliding batt kiln wherein, when the kiln is in use, sliding batts are transported along and through the three zones of the kiln to convey products carried thereby through the kiln to effect the firing of said products, charac ⁇ terised in that the kiln comprises guide rails on which the sliding batts are transported as aforesaid, the kiln also comprising an underflow channel over which, when the kiln is in use, the products are transported on the sliding batts as aforesaid thereby ensuring the even firing of the products.
  • baffle means are provided in said underflow channel of the first and third zones to further ensure the even firing of the products as aforesaid wherein said baffle means comprise wall portions provided across a floor of the underflow channel whereby, when the kiln is in use and products are being carried on said sliding batts as aforesaid, the flow rates of heating and cooling gases over and under the product and batt respec ⁇ tively in said first and third zones respectively are such that the rate of heat transfer to and from each side of the product and batt is equal or substantially so.
  • the wall portions are provided at spaced intervals along said floors of the underflow channel in the first and third zones of the kiln wherein said wall portions conveniently create, when the kiln is in use, a weir effect to control the flow rates of the heating and cooling gases as aforesaid and the guide rails are conveniently provided by lower inwardly projecting stub walls of an inverted "U" shaped channel section which extends along and through the three zones of the kiln.
  • the underflow channel in the second zone of the kiln is deeper than the underflow channels in the first and third zones and in the second zone the inverted "U" shaped channel section is at least twice as deep as the inverted "U” shaped channel sections of zones one and three of the kiln and wherein the channel sections are conveniently made from silicon carbide.
  • the present invention also conveniently provides a kiln wherein first and second air-locks are provided at upstream and down ⁇ stream ends respectively of the kiln and propulsion means are provided for causing, when the kiln is in use, the sliding batts to be propelled seriatim through the kiln from the upstream side of said first air-lock to the downstream side of said second air-lock.
  • the invention also conveniently provides a kiln according to the last preceding paragraph wherein the propulsion means includes transfer means provided at the downstream end of the kiln whereby, when the kiln is in use and after it has received its full complement of sliding batts, and while an upstream end said second air-lock is open to connect the kiln therewith a a downstream end of said second air-lock is closed, a slidi batt is engaged by said transfer means and conveyed thereby in said second air-lock, said transfer means also being operati when the kiln is in use and an upstream end of the seco air-lock is closed to isolate the kiln therefrom and t downstream end of the second air-lock is open, to convey sa sliding batt out of the second air-lock.
  • the propulsion means includes transfer means provided at the downstream end of the kiln whereby, when the kiln is in use and after it has received its full complement of sliding batts, and while an upstream end said second air-
  • the invention still further provides a kiln wherein t propulsion means for propelling the sliding batts seriati through the kiln is provided by an indexing mechanism provid upstream of said first zone thereof, the forward end of o sliding batt engaging with the trailing end of the sliding bat immediately downstream thereof to transfer the stroke of th indexing mechanism to all of the batts in the kiln, and wherei the sliding batts are provided by "setters" or “cassettes” whic may conveniently be made from cordierite.
  • the kiln operates at an energy consumption rate o less than 2.5 MJ/kg weight of the products fired therein, th products preferably being profiled clay roofing tiles as herein before defined.
  • a preferred composition for use in the manufacture of a fire clay roof tile said composition comprises:
  • composition has a particle size of less than 150 microns with a median particle size of between 40 to 50 microns, said tile being produced by the process and in the kiln as hereinbefore defined.
  • Figure 1 is a schematic plan view of a kiln assembly
  • Figure 2 is a schematic section view of a heating zone of the kiln along the line II-II of Figure 1;
  • Figure 3 is a schematic section view of a firing zone of the kiln along the line III-III of Figure 1;
  • Figure 4 is a schematic section view of an input end of the kiln along the line IV-IV of Figure 1;
  • Figure 5 is a schematic section view of an output end of the kiln along the line V-V of Figure 1;
  • Figures 6a to 6h are foreshortened schematic side views of the kiln illustrating operational sequences thereof.
  • Figure 7 is a composite view of a temperature/time graph over a block schematic of the kiln of Figure 1.
  • the present invention provides a novel process which is effected in a kiln 2 of a kiln assembly 4, see Figure 1, which process enables the production of clay roof tiles from a composition comprising a clay/rock flow blend, said roof tiles being produced in said kiln in less than 40 minutes and at an energy consumption rate of less than 2.5 MJ/kg of tile weight.
  • the kiln 2 as shown in Figures 1 to 7, is of one-high configu ⁇ ration, that is, it is only capable of receiving products one at a time in a continuous stream, which products, when the kiln is in use, are carried therethrough on sliding batts 5 supported for this purpose as hereinafter described on a pair of spaced apart rails 1 which extend in a contiguous channel 3 provided throughout the length of the kiln 2.
  • the kiln 2 is made up of thirteen sections 6 to 18, see Figure 1.
  • Sections 6, 7 and 8 provide a first zone 20 of the kiln 2 in which first zone a rising temperature gradient is created when the kiln 2 is in use.
  • Sections 9 and 10 provide a second zone 22 of the kiln 2 and are the plenum chambers of the kiln 2 where arrays of burners 24 and 25 are provided to create an even, or substantially even, "peak-firing" temperature there ⁇ through when the kiln is in use.
  • Sections 10 to 18 provide a third zone 26 of the kiln 2 in which third zone 26 a cooling temperature gradient is created when the kiln 2 is in use.
  • section 7 comprises a fabricated metal kiln casing 30 of generally rectangular section supported on a floor mounted fabricated metal frame 32.
  • section 7 comprises support brickwork, that is insulating brick ⁇ work, 34, in a lower half thereof with a channel portion 36 of the channel 3 being formed in an upper mid-section 38 of said brickwork 34, see Figure 2.
  • the channel portion 36 is substan ⁇ tially "T" shaped in longitudinal cross-section.
  • the brickwork 34 defines upper left and right hand horizontal arms 40 and 42 of the channel portion 36 to provide support for left and right hand rail sections 44 and 46 respectively of the rails 1, see Figure 2.
  • the rail section 44 is of "L” shape in longitudinal cross-section and the rail section 46 is of reverse “L” shape in longitudinal cross-section, see also Figure 2.
  • the channel portion 36 of the section 7 is provided with wall portions 48 on a floor 50 of the channel portion 36, the purpose of which wall portions 48 will be made clear hereinafter.
  • the wall portion 48 fills approximately half of a vertical stem of the "T" shaped channel portion 36 with left and right hand gaps 52 and 54 being evident at either end of the wall portion 48 between itself and the brickwork 34.
  • Section 7 is completed by fibre insulation 58 which is provided in an upper half thereof, as shown in Figure 2.
  • the sections 6, 7 and 8 are bolted together in known manner with the channel portions 36 and rail sections 44 and 46 thereof in alignment.
  • the sections 11 to 18 are bolted together in known manner with the channel portions 36 and rail sections 44 and 46 thereof in alignment.
  • section 9 comprises a fabricated metal kiln casing 60 of generally rectangular section supported on a floor mounted fabricated metal frame 62.
  • section 9 comprises support brickwork, that is insulating brickwork, 64, in a lower half thereof with a channel portion 66 of the channel 3 being formed in an upper mid-section 68 of said brickwork 64, see Figure 3.
  • the channel portion 66 is of exaggerated "T" shape in longitudinal cross-section with the depths of the limbs and stem of the "T" section being at least twice the depth of the corresponding limbs and stems in the sections 6, 7 and 8 of the first zone.
  • the brickwork, defining upper horizontal arms 70 and 72 of the channel portion 66, provides support for left and right hand rail sections 74 and 76 respectively of the rails 1.
  • the rail section 74 is of "L" shape in longitudinal cross- section and the rail section 76 is of reverse “L” shape in longitudinal cross-section, see Figure 3.
  • Section 9 also comprises fibre insulation 78 which is provided in an upper half thereof, as shown in Figure 3.
  • Section 9 comprises the arrays of burners 24 and 25 arranged on opposite sides respectively of the section 9 which burners 24 and 25 may be of any suitable configuration as illustrated schematically in Figure 3.
  • the sections 9 and 10 are bolted together in known manner.
  • the kiln 2 is completed by bolting the three zones 20, 22 and 24 together in known manner with the channel portions 36 of sections 6 to 8 and 11 to 18 arranged in substantial alignment with the channel portions 66 to provide the channel 3 in which the rail sections 44 and 46 and 74 and 76 respectively are also arranged in substantial alignment to provide the pair of rails 1.
  • the kiln assembly 4 includes propulsion means 90 whereby, when the assembly is in use, products are propelled through the length of the kiln 2.
  • the propulsion means 90 comprises an indexing mechanism 92 of conventional configuration at an upstream end 94 of the kiln 2.
  • the mechanism 92 com ⁇ prises a piston and cylinder arrangement 96 which is connected to a pusher rod 98 which in turn carries a pusher plate 100 at a leading right hand end 102 thereof, see Figures 6a to 6h, the purpose of which plate 100 will be made clear hereinafter.
  • the propulsion means 90 also comprises a transfer means 104 provided by a short belt conveyor arrangement 106 at a down ⁇ stream and 108 of the kiln 2, the purpose of which arrangement 106 will also be made clear hereinafter with reference to Figures 6a to 6h.
  • the kiln assembly also comprises a first air-lock 110 at said upstream end 94 of the kiln 2 and a second air-lock 112 at said downstream end 108 thereof, the purpose of which air-locks 110 and 112 will be made clear hereinafter.
  • the first air-lock 110 is located at and fixedly secured to the upstream end 94 of the kiln 2 as aforesaid between the kiln 2 and the indexing mechanism 92 as shown in Figures 6a to 6h.
  • the first air-lock 110 comprises an inner door 114 mounted on a rod 116 of an associated piston and cylinder arrangement 118 which inner door 114, in an operative sequence with respect to the pusher plate 100, which also acts as an outer door of the air-lock, when the kiln is in use, ensures that the upstream end 94 of the kiln 2 is isolated in use.
  • the second air-lock 112 is located at and fixedly secured to the downstream end 108 of the kiln 2 as aforesaid and comprises an inner door 120 mounted on a rod 122 of an associated piston and cylinder arrangement 124 and a pivotally mounted outer door 125 pivotally connected to a piston rod 126 of an associated piston and cylinder arrangement 128, see Figures 6a to 6h.
  • the doors 120 and 122 are operated in sequence to isolate the kiln 2 when it is in use.
  • the kiln assembly 4 further comprises a product feed mechanism 130 which straddles said indexing mechanism 92 at the upstream end 94 of the kiln 2.
  • the mechanism 130 consists essentially of conventional elevator means for presenting products P to the pusher plate 100 when the kiln 2 is in use as hereinafter described.
  • the kiln assembly 4 comprises a product despatching mechanism 132 downstream of the transfer means 104, see Figures 6a to 6h.
  • the mechanism 132 comprises a short longitudinal conveyor assembly 134 arranged in line with said transfer means 104, the assembly 134 being carried by a lateral transfer mechanism 136 of the mechanism 132.
  • the kiln assembly 4 also comprises a return loop conveyor 138 connected between the mechanism 132 and the product feed mecha ⁇ nism 130 for a purpose to be made clear hereinafter.
  • Green state roof tiles i.e. the products, are produced from a composition comprising:
  • composition has a particle size of less than 200 microns with a median particle size of between 20 and 60 microns.
  • the composition comprises between 40 and 60 parts by weight of clay and 0 to 40 parts by weight of rock flour and the particle size is less than 150 microns with a median particle size of between 40 and 50 microns.
  • composition with added water is thoroughly mixed to give a homogenous mixture which is introduced into a conventional tile moulding press; thereafter the "green state” products are dried before being fed seriatim to the kiln assembly 4.
  • the cassettes 5 together with the products P mounted thereon are fed one at a time on to a support frame 131 of the product feed mechanism 130 when in the position as shown in Figure 6a.
  • the support frame 131 With the piston rod 98 retracted, i.e. moved to the left viewing Figure 6a, to the position shown in Figure 6c, the support frame 131 is lowered into alignment with extension portions la of the rails 1.
  • the inner door 114 is activated by the piston and cylinder arrangement 118 to isolate the kiln 2 from atmosphere.
  • the piston and cylinder arrangement 96 is then operated to cause movement of the cassette 5 to the right viewing Figure 6a to introduce the product P into the kiln 2, the door 100 acting as a pusher plate for this purpose.
  • the inner door 114 is opened to allow the cassette 5 and product P to be moved into the kiln 2 as shown in Figure 6a.
  • FIG. 6b shows the pusher-plate door 100 during a fast return stroke of the piston and cylinder 96 in preparation for the feeding of a subsequent cassette 5 and product P supported at this time on the support frame 131 of the mechanism 130. It is to be noted that the doors 114, 120 and 125 are all closed at this time.
  • Figure 6c shows the support frame 131 lowered into alignment with the extension rails 1, the doors 114, 120 and 125 still being closed.
  • Figure 6d shows the pusher-plate door 100 during a fast forward stroke of the piston and cylinder arrangement 96, the cassette' 5 and product P being located wholly within the air-lock 110 which is closed by the door 100 enabling the sequential operation of the piston and cylinder arrangement 118 to open the door 114 thereby facilitating the entry of the cassette 5 and product P to the kiln 2.
  • the arrangement 96 is operated slowly to inch the cassette forward, i.e. to the right in Figure 6d to bring a forward end thereof into pushing engage ⁇ ment with a trailing end of a preceding cassette 5.
  • the slow pushing stroke of the arrangement 96 continues, where ⁇ upon the line of cassettes 5 and products P is slowly moved towards the right, viewing Figure 6e, to bring a leading cassette 5 into juxtaposition with the inner doors 120 which is opened upon sequential operation of the piston and cylinder arrangement 124 to allow the leading cassette to enter the air-lock 112 as shown in Figure 6f.
  • the doors 100 and 125 are closed and the doors 114 and 120 are open.
  • the slow pushing stroke of the arrangement 96 continues as the transfer means 104 is operated sequentially to firstly transfer the leading cassette 5 wholly into the air-lock 112 whereupon the door 120 closes and the door 125 opens, see Figure 6g, to allow the leading cassette 5 to be transferred partially onto an endless conveyor 132 of the conveyor assembly 134. Operation of the conveyor 132 positions the leading cassette 5 for subsequent transfer to a splitting arrangement 140 shown in block form in Figure 1. At this time, the arrangement 96 completes its forward stroke to once again position the next in line cassette 5 adjacent the door 120, see Figure 6h, and the door 125 closes once again to isolate the kiln 2. It will be obvious that the above sequence of operation is repeated while cassettes 5 and products P are fed to the kiln assembly 4.
  • each product P is subjected to a process provided by the invention and comprising the steps of:
  • the products P are subjected to a rising temperature gradient along zone 20, a constant temperature profile in zone 22 and a diminishing temperature gradient in zone 26.
  • These conditions are provided by the size of burners in zone 22, the mass of the products P and cassettes 5 propelled through the kiln, the speed at which the products P and cassettes 5 are propelled through the kiln 2, the counterflow current of air which is introduced at the downstream end 108 of the kiln 2 and exited at the upstream end 94 thereof and the quantity of air provided in counterflow.
  • the three zones of the kiln act effec ⁇ tively as heat exchangers with the air giving up its heat to the product and cassettes in zones 20 and 22 and with the products and cassettes giving up their heat to the incoming air in zone 26 of the kiln.
  • the heat exchange as between the air and the products and vice versa is also assisted in no small measure by the wall portions 48 which are provided at intervals through the length of the zones 20 and 26. It will be appreciated that the geometry of a product being propelled through the kiln 2 presents an uneven upper surface to the air passing thereover in counterflow and thus, without the wall portions 48, the air in the lower portion of the channel 3 would pass through said lower portion unimpeded leading to a differential heating and cooling as between the upper and lower surfaces of the products P.
  • the effect created by the wall portions 48 is to locally pressurise the air in the lower channel portion to eliminate or at least to reduce the pressure differential as between the air-flow over and under the products P thereby enhancing even heat exchange as between the products P and the air and vice versa in the zones 20 and 26.
  • cassettes 5 utilised measure 0.28 m wide and 0.457 m long and when fully loaded there are 53 such cassettes 5 in the kiln 2.
  • the fast forward stroke of the pusher-plate door 100 is effected at 0.5 m/s and lasts for 1.25 seconds, while the slow forward stroke of the pusher-plate door 100 is effected at 0.0175 m/s and lasts for 29 seconds and the return stroke of the pusher plate is effected at 0.5 m/s and lasts for 2 seconds approximately.
  • Products subjected to the novel process when carried out in the improved kiln of this invention consumed 2.5 MJ/kg of product weight and gave an end product, i.e. a clay roof tile having a cross-bending strength of between 10 and 30 MPa and with acceptable frost resistance and permeability.
  • Modifications envisaged within the scope of the invention include a multi-channel kiln with appropriate buffers between each, channel if required; however, it is envisaged that judicial tailoring of any wall between each channel will enable the present side wall mounted configuration of burners to be used without excessive modification thereto.
  • each channel may be omitted in the second zone 22 of the kiln 2 and that the arrays of burners 24 and 25 may be complemented by or replaced by burners located in the roof and floor of the second zone 22.
  • each zone 20, 22 and 26 may be of unitary construction instead of the modular construction described herein.
  • the rail sections 44, 46, 74 and 76 may be provided by continuous rails extending the length of the kiln 2 and may, in fact, be provided by lower inwardly projecting stub walls of an inverted "U" shape channel section which is arranged to extend along and through the three zones of the kiln.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Dispersion Chemistry (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Furnace Charging Or Discharging (AREA)

Abstract

Procédé de cuisson de tuiles de toiture en argile élaborées à partir d'une composition renfermant: 1) de soixante à cent parties en poids d'argile; et 2) de zéro à quarante parties en poids de poudre de friction, cette composition étant constituée au moins à 95 % de particules inférieures à 150 microns, le calibre moyen des particules étant compris entre 40 et 50 microns. Ce procédé comporte trois étapes, réalisées dans un four continu à fort contre-courant dans un délai compris entre 33 et 55 minutes et généralement égal à 33 minutes pour une consommation d'énergie comprise entre 1,5 et 3,4 MJ/kg de poids de tuile et généralement inférieure à 2,5 MJ/kg de poids de tuile.
PCT/EP1993/003173 1992-11-17 1993-11-12 Fabrication de tuiles de toiture Ceased WO1994011321A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU55625/94A AU5562594A (en) 1992-11-17 1993-11-12 Manufacture of roof tiles

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9224091.0 1992-11-17
GB929224091A GB9224091D0 (en) 1992-11-17 1992-11-17 Manufacture of roof tiles

Publications (1)

Publication Number Publication Date
WO1994011321A1 true WO1994011321A1 (fr) 1994-05-26

Family

ID=10725226

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1993/003173 Ceased WO1994011321A1 (fr) 1992-11-17 1993-11-12 Fabrication de tuiles de toiture

Country Status (3)

Country Link
AU (1) AU5562594A (fr)
GB (2) GB9224091D0 (fr)
WO (1) WO1994011321A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2484057C1 (ru) * 2012-03-07 2013-06-10 Юлия Алексеевна Щепочкина Керамическая масса для изготовления напольной плитки
RU2493127C1 (ru) * 2012-06-14 2013-09-20 Юлия Алексеевна Щепочкина Сырьевая смесь для изготовления облицовочной плитки
RU2495848C1 (ru) * 2012-07-03 2013-10-20 Юлия Алексеевна Щепочкина Керамическая масса для изготовления облицовочной плитки
RU2510383C1 (ru) * 2013-01-15 2014-03-27 Юлия Алексеевна Щепочкина Керамическая масса для изготовления облицовочной плитки

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2140888C1 (ru) * 1997-12-18 1999-11-10 Центральный научно-исследовательский институт геологии нерудных полезных ископаемых (ЦНИИгеолнеруд) Керамическая масса для изготовления стеновых изделий, преимущественно кирпича керамического
RU2176223C1 (ru) * 2000-03-28 2001-11-27 Центральный научно-исследовательский институт геологии нерудных полезных ископаемых Керамическая масса для изготовления строительных изделий
RU2197446C2 (ru) * 2001-03-06 2003-01-27 Центральный научно-исследовательский институт геологии нерудных полезных ископаемых Керамическая масса для изготовления керамического кирпича
RU2440946C2 (ru) * 2010-03-22 2012-01-27 Геннадий Дмитриевич Ашмарин Сырьевая смесь для изготовления керамических теплоэффективных стеновых изделий

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FR2153883A5 (en) * 1971-09-13 1973-05-04 Riedhammer Ludwig Firme Batt conveyor system - for ceramics tunl kilns
DE2658489A1 (de) * 1976-12-23 1978-06-29 Riedhammer Ludwig Fa Ofen zum sintern magnetkeramischer ware
FR2517295A1 (fr) * 1981-11-27 1983-06-03 Impianti Termoelettrici Ind Procede et installation pour la cuisson de matieres ceramiques
SU1211241A1 (ru) * 1983-04-04 1986-02-15 Научно-исследовательский и проектно-конструкторский институт строительных материалов им.С.А.Дадашева Керамическа масса дл изготовлени облицовочных плиток
DD278919A3 (de) * 1987-11-16 1990-05-23 Akad Wissenschaften Ddr Dichte keramische formkoerper und verfahren zu ihrer herstellung
DE4034653A1 (de) * 1990-10-31 1992-05-07 Loi Ind Ofenanlagen Verfahren und durchstossofen zum waermebehandeln von werkstuecken

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US4089920A (en) * 1970-12-14 1978-05-16 Stephens John A High-strength, light-weight, fired clay body and method of producing same
DD156391A1 (de) * 1981-02-16 1982-08-18 Hartwig Thiele Durchlaufofen mit schlittenfoerderung,insbesondere fuer den einsinkfarbenbrand

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Publication number Priority date Publication date Assignee Title
FR2153883A5 (en) * 1971-09-13 1973-05-04 Riedhammer Ludwig Firme Batt conveyor system - for ceramics tunl kilns
DE2658489A1 (de) * 1976-12-23 1978-06-29 Riedhammer Ludwig Fa Ofen zum sintern magnetkeramischer ware
FR2517295A1 (fr) * 1981-11-27 1983-06-03 Impianti Termoelettrici Ind Procede et installation pour la cuisson de matieres ceramiques
SU1211241A1 (ru) * 1983-04-04 1986-02-15 Научно-исследовательский и проектно-конструкторский институт строительных материалов им.С.А.Дадашева Керамическа масса дл изготовлени облицовочных плиток
DD278919A3 (de) * 1987-11-16 1990-05-23 Akad Wissenschaften Ddr Dichte keramische formkoerper und verfahren zu ihrer herstellung
DE4034653A1 (de) * 1990-10-31 1992-05-07 Loi Ind Ofenanlagen Verfahren und durchstossofen zum waermebehandeln von werkstuecken

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DATABASE WPI Week 8638, Derwent World Patents Index; AN 86-251189 *
DATABASE WPI Week 9043, Derwent World Patents Index; AN 90-321119, MUCKE ET AL.: "DENSE CERAMIC ARTICLE" *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2484057C1 (ru) * 2012-03-07 2013-06-10 Юлия Алексеевна Щепочкина Керамическая масса для изготовления напольной плитки
RU2493127C1 (ru) * 2012-06-14 2013-09-20 Юлия Алексеевна Щепочкина Сырьевая смесь для изготовления облицовочной плитки
RU2495848C1 (ru) * 2012-07-03 2013-10-20 Юлия Алексеевна Щепочкина Керамическая масса для изготовления облицовочной плитки
RU2510383C1 (ru) * 2013-01-15 2014-03-27 Юлия Алексеевна Щепочкина Керамическая масса для изготовления облицовочной плитки

Also Published As

Publication number Publication date
GB2272432B (en) 1996-06-26
GB2272432A (en) 1994-05-18
GB9224091D0 (en) 1993-01-06
AU5562594A (en) 1994-06-08
GB9323200D0 (en) 1994-01-05

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