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
  • F27D5/00—Supports, screens, or the like for the charge within the furnace
  • F27D5/0062—Shields for the charge
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
  • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
  • C03B5/42—Details of construction of furnace walls, e.g. to prevent corrosion; Use of materials for furnace walls
• • 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
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/0003—Linings or walls
  • F27D1/0006—Linings or walls formed from bricks or layers with a particular composition or specific characteristics
  • F27D1/0009—Comprising ceramic fibre elements
• • 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
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/0003—Linings or walls
  • F27D1/0033—Linings or walls comprising heat shields, e.g. heat shieldsd
• • 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
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/04—Casings; Linings; Walls; Roofs characterised by the form, e.g. shape of the bricks or blocks used

Definitions

• the invention relates to a method for thermal insulating of a furnace for high temperature, for example a glass furnace, and a furnace manufactured in accordance with this method.
• Glass furnaces have usually consisted up to the present of a mortar laid brick wall which is lined on the inside with thermally insulating material.
• the brick wall serves not only as insulator but also as support frame for the insulating material.
• Such a wall has to be made on site for the user. It is not possible to manufacture this furnace in a factory and then transport it to the location of use.
• the furnaces are usually of a size such that there is space therein for various glass pots, in which the glass is melted. Such furnaces are expensive and have a limited output.
• this is achieved by arranging the heat reflecting surface layer by applying a substance containing silicon, by then subjecting the furnace to great heat and cooling it rapidly thereafter.
• the furnace insulated in this way can be light because the furnace shell can be of sheet metal.
• a heat reflection is obtained in the micro-structure of the ceramic fibre, while the ceramic fibre otherwise ramins soft and preserves its thermal insulating value.
• the heat reflecting surface layer can be arranged by applying a substance containing silicon, by then greatly heating the furnace and cooling it rapidly thereafter. Thus achieved is that only a surface layer in the micro-structure melts and becomes hard after cooling, whiel the rest of the fibre material remains soft and therefore preserves the thermal insulating transfer properties.
• the reflecting surface layer is aplied by heating the furnace to approximately 1500° C and by then cooling it down to about 1250° C.
• the silicon holding substance may for example be a sort of water-glass.
• the heat reflecting layer is fire resistant.
• the ceramic fibre material is not in itself self-supporting without steps being taken to achieve this.
• the fibre material is arranged on the side wall of a cylindrical furnace using the following steps: a. fibre material is pressed and strapped up into vertical blocks of trapezium form section, b. blocks formed as according to step a. are disposed abutting one another against the cylindrical inner wall such that the whole inner surface is covered, and c. the strapping of the individual blocks is removed and the blocks allowed to expand.
• the blocks of cylindrical material after the removal of the strapping and expansion resulting from the opposing forces generated by the pressing, come to lie stiffly against one another and joins between the blocks which could cause thermal leakage are closed.
• the furnace is preferably a cylinder open to the bottom which is placed loose on a base plate and whereby the cylinder and the base plate are insulated in the manner as described in the foregoing.
• the open cylinder thus functions as a kind of hat which can easily be removed from the base plate. This yields the advantage that the glass pot can be taken very easily and quickly out of the furnace and placed therein by lifting the hat and setting it in inclined position.
• the layers of insulating material are arranged overlapping to prevent thermal leakage.
• Microtherm *& can be used, while the ceramic fibre material can be Fiberfrax ® which is supplied by The Carborundum Company, Niagara Falls, N.Y.
• the blocks can be pressed from parallel strips of material, whereby in the zone to be pressed into the convex side of the block of trapezium form section are arranged additional strips of material. As a result the density on the hot side is greatly increased.
• Fig. 1 shows a perspective view of a furnace according to the invention
• fig. 2 shows a sectional view along the line II-II from fig. l
• fig. 3 shows a press for pressing the blocks of ceramic fibre material
• fig. 4 and 5 are views of the pressing operation
• fig. 6 shows a strapped block of pressed ceramic fibre material
• fig. 7 shows in perspective view the manner of removal of a glass pot and the placing thereof in the furnace according to the invention
• fig. 8 shows a cylindrical insulating arrangement for a heat exchanger for recovering energy from waste gases, for instance from a blast-furnace.
• the furnace 1 consists of a cylindrical metal shell 2, layers 3, 4 of insulating material, for example
• the furnace contains a door 6 for removal of melted glass from the glass pot 7.
• the parallelogram mechanism 8, 9 the door 6 is movable between a closed position and the folded down open position illustrated.
• the furnace further displays an outlet 10 on the underside for discharge of leakage glass.
• the burner installation 11 which is for instance gas fired.
• a connection 12 for joining to a flue uptake for discharge of combustion gases is also present.
• the feed 13 for hot air debouches into the furnace such that the hot air flows run tangentially to the glass pot 7. The air flow moves in circles round the glass pot and heats it in efficient manner.
• the insulating layer of ceramic fibre 5 is built up of vertical blocks, for instance 14, that are trapezium form in section (fig. 6) .
• Such blocks are manufactured in a press 15 (fig. 3).
• the press 15 contains a movable valve 16 which is actuated by an angle lever system 17, 18.
• the strips 19, 19', 19' ' ... are placed in the press, whereby cross strips 20, 20' , 20' ' ... are positioned on the convex side between the strips 19, 19*, 19 • ' ... (fig. 4).
• After pressing (fig. 5) a greater density results in the convex zone 21 than on the zone 22 located more to the outside.
• Arranged in the press are groove-like peripheral recesses 23, 23', 23" ' ...
• binding or strapping material in the form of wire or cord 24. After pressing the different cords 24 are tied in position.
• the thus formed blocks are disposed vertically along the cylindrical shell (see fig. 2 and 6). After the whole peripheral wall is provided in this manner with blocks the strappings of the various blocks are cut through, which results in the blocks expanding and abutting one another precisely, thereby filling up all the connecting seams between the successive blocks.
• the furnace is built up of a hat consisting of the cylindrical peripheral shell which is closed off at the top 05 by an upper surface 25 that is insulated in the same manner as the side walls.
• the said hat is positioned loosely on a base plate 27 which is likewise insulated in the same way as the side walls.
• the very weight of the hat is sufficient for sealing relative to base plate 27.
• the whole stands on a grid 10 28 which rests on the ground with legs 29 such that the whole can be lifted up by a fork-lift truck.
• the thus constructed furnace is sprayed on the interior, for example with a sort of water-glass, and subsequently heated to approximately 1500° C. After this 15 temperature has been reached, rapid cooling to about 1250° C is carried out. Achieved as a result is the melting of the surface structure of the ceramic fibres on the hot side (the interior of the wall). This takes place in the micro-structure of the ceramic fibre. During this process the 0 water-glass holds together the small piees of ceramic fibre before they begin to melt. This surface treatment may be called glazing only so deep as sprayed solution would penetrate the body of a block. Thereby obtained is a heat reflecting surface layer that is fire resistant, while the 5 rest of the ceramic fibre blocks remain soft, therefore preserving high thermal insulating properties.
• Glass pots that are placed in a glass furnace and in which the glass for melting is placed have to be brought to temperature gradually. Too rapid temperature changes 0 result in a considerable lessening in the useful life of such glass pots.
• Glass pots are generally pre-heated in a tempering oven other than the glass-melting furnace (arch oven). In accordance with the invention the useful life of glass pots can be extended considerably. 5 This is achieved by employing a tempering oven built according to the same principle like glassmelting furnace by which the exchange of pots is happening within 30 seconds, which considerably decreases the time needed compared to traditional systems (see figure 7). During insertion or removal of the glass pot the tempering oven is disconnected from the gas supply for the burner and from the connection with the discharge for the combustion gases.
• the tempering oven together with the grid 28 is then lifted using a fork-lift truck and transported to a point close to the opening doors of the furnace into which the glass pot has to be placed.
• a lifting device the hat of the tempering oven, consisting of a cylindrical shell and the top plate 25, is then raised and optionally set in inclined position.
• the pot can subsequently be removed from the tempering oven using a forked body 30 and placed in the glass melting furnace 31. All this can be carried out very rapidly, which results in a possibility to keep the period, during which the glass pot is exposed to a considerably lower temperature, limited (30 seconds) .
• Fig. 8 shows such an insulated cylinder as part of a chimney of a blast-furnace.
• a heat exchanger 33 which recovers the thermal energy in the waste gases of the blast-furnace. Due to the good insulation little heat is lost to the outside.
• As a result of the light construction it is possible to arrange such a cylindrical shell at a height. Such is not possible using the classical lining of furnaces, chimneys and the like with mortar laid brick walls.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Ceramic Engineering (AREA)
• Furnace Housings, Linings, Walls, And Ceilings (AREA)
• Furnace Details (AREA)
• Control Of High-Frequency Heating Circuits (AREA)
• Thermal Insulation (AREA)
• Laminated Bodies (AREA)
• Organic Insulating Materials (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19853976

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (1)

Citations (7)

Family Cites Families (6)

• 1989
  • 1989-01-18 NL NL8900114A patent/NL8900114A/nl not_active Application Discontinuation
• 1990
  • 1990-01-18 DK DK90902705.4T patent/DK0454774T3/da active
  • 1990-01-18 ES ES90902705T patent/ES2043358T3/es not_active Expired - Lifetime
  • 1990-01-18 AT AT90902705T patent/ATE93050T1/de not_active IP Right Cessation
  • 1990-01-18 US US07/721,627 patent/US5257929A/en not_active Expired - Fee Related
  • 1990-01-18 DE DE90902705T patent/DE69002757T2/de not_active Expired - Fee Related
  • 1990-01-18 EP EP90902705A patent/EP0454774B1/en not_active Expired - Lifetime
  • 1990-01-18 WO PCT/NL1990/000008 patent/WO1990008297A1/en active IP Right Grant

Patent Citations (7)

Non-Patent Citations (1)

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