US3494601A - Tunnel kilns with roof - Google Patents

Tunnel kilns with roof Download PDF

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Publication number
US3494601A
US3494601A US723987A US3494601DA US3494601A US 3494601 A US3494601 A US 3494601A US 723987 A US723987 A US 723987A US 3494601D A US3494601D A US 3494601DA US 3494601 A US3494601 A US 3494601A
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United States
Prior art keywords
kiln
tunnel
roof
length
burners
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Expired - Lifetime
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US723987A
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English (en)
Inventor
Gottfried Cremer
Heinz Behrens
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Individual
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Individual
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Classifications

    • 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
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/36—Arrangements of heating devices
    • 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
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/3005—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases
    • 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
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B2009/305—Particular conformation of the furnace
    • F27B2009/3055—Non-uniform section through the length of the furnace
    • 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
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/36—Arrangements of heating devices
    • F27B2009/3638—Heaters located above and under the track
    • 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 tunnel furnace
    • 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 tunnel furnace on or in trucks, sleds, or containers
    • F27B9/262—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 tunnel furnace on or in trucks, sleds, or containers on or in trucks

Definitions

  • the tunnel of a tunnel kiln as used in the ceramics industry can generally be divided into a pre-firing zone or length, a firing zone or length and a following cooling length. While in the pre-firing length and in the cooling length there are usually no heating arrangements and the transfer of heat to and from the articles to be fired takes place by means of heat exchangers, for example by means of pipe coils carrying a liquid heat exchanging medium, in the firing length burners operated by fluid fuel, that is to say liquid or gaseous fuel, are provided. It is also possible to heat the ring length electrically.
  • the present invention is more particularly concerned with tunnel kilns whose ring lengths are heated by means of uid operated burners.
  • the combustion air required for the burning of the fluid fuel can either be fed to the burners directly or the tunnel kiln can be operated in accordance with the circular or ring kiln principle.
  • the kiln atmosphere is drawn into the tunnel by the tunnel draught at the end at which the trolleys leave the kiln.
  • the kiln atmosphere then passes through the cooling length, the tiring length and finally the pre-firing length or zone from which it is removed by ues.
  • the kiln atmosphere thus moves substantially horizontally along the tunnel from the exit end, that is to say the end at which the goods leave the kiln, to the inlet end.
  • the burners red with fluid fuel are generally arranged in the ring length of the tunnel approximately at the same height as to the platforms of the trolleys on which the goods to be fired are stacked. Generally the burners are arranged so as to be transverse in relation to the direction of travel of the trolleys along the tunnel.
  • the horizontal movement of the tunnel kiln atmosphere from the cooling length and then through the firing length has the consequence that with the above mentioned arrangement of the burners at the height of the platform of the trolleys at the end of the firing length, that is to say adjacent to the last burner or burners, the temperature characteristic of the kiln atmosphere due to the heating effect of the last burner or burners, and therefore also the temperature of the material to be red does not increase in an upmard direction as would be the case with a simple upward movement of the kiln atmosphere, due to the heating eiect, without the superposed horizon- 3,494,601 Patented Feb.
  • the flow pressure and draught relationship in the burning zone of a tunnel kiln are of complex character: the heated kiln atmosphere tends to rise owing to natural thermal upthrust and this in itself has the tendency to lead to the production of substantially higher temperatures under the roof of the kiln than the level of the carrying surfaces of the trolleys. Measurements show that the boundary layer immediately under the tunnel kiln roof has the highest temperature. On the other hand owing to the chimney draught there is complex intluencing of this tendency for the highest temperature to be immediately under the roof.
  • One object of the present invention is to prevent this disturbance of the desired temperature characteristic in the part of the kiln heated by the last burner or burners of the ring zone.
  • a further object of the invention is to prevent this disturbance using simple means.
  • a further object of the invention is to prevent the disturbance using means which influence the gas flow directly, that is to say by direct liow guiding means rather than by further heating or cooling means,
  • the tunnel roof at the downstream end of the firing length of the kiln is at a higher level than the remaining parts of the firing zone.
  • the roof can have an upwardly extending recess in the form of an inverted transverse channel.
  • Fluid burning burners can be arranged under the part of the roof at the higher level.
  • FIG. l is a longitudinal section through a tunnel kiln of conventional construction with diagrammatic representation of the flow of the kiln atmosphere and the gaseous products of combustion rising from the burners.
  • FIG. 2 is a longitudinal section in accordance with FIG. 1 modied in accordance with the invention.
  • FIG. 3 is a somewhat modied embodiment of the tunnel in accordance with FIG. 2.
  • FIG. 4 is a section on the line 3 3 of FIG. 3.
  • FIG. 5 is a section on the line 3 3 of FIG. 3 in the case of a tunnel kiln with -a vaulted roof.
  • reference numeral 1 denotes a tunnel kiln shown diagrammatically in section.
  • A, B, and C denote, respectively, the cooling zone or length of the kiln, the tiring length and the pre-firing length of the kiln.
  • the arrow D denotes the direction of travel of trolleys, not shown, in FIG. l.
  • the horizontally owing kiln atmosphere is denoted by arrow 1 while the arrows directed obliquely upwards denote gaseous products of combustion rising from the burners 3.
  • the arrows 21r denote the horizontally moving atmosphere travelling along through vthe cooling length of the tunnel.
  • Reference numeral 23 indicates burners in the firing length B.
  • the gaseous products of combustion rising from these burners 23 can in this case move upwards without being disturbed 'along the paths 22.
  • the practically undisturbed upward movement of these gaseous products of combustion is due to the fact that at the downstream end of the firing length or zone of the kiln the kiln roof is Vat a substantially higher level at 24 than at the position 25.
  • this part of higher level 24 is due to the provision of a transverse inverted channel-shaped recess in the roof structure.
  • the horizontally moving kiln atmosphere can move in an upward direction as is indicated by reference numeral 26 so that the horizontal ow is no longer sucient to displace the gaseous products of combustion 22 rising from the burners 23, as is shown in the construction of FIG. l, in an arcuate manner in the direction of the goods inlet end D of the kiln.
  • FIG. 3 shows an embodiment of the invention in which under the corresponding raised part 34 of the roof 35 there are additional burners 37 above the goods to be iired.
  • These burners are preferably operated with fluid fuel, that is to say oil or gas which heats the goods to be red from above substantially by radiation.
  • Reference numeral 32 denotes the burners at the bottom of the kiln while reference numeral 36 denotes the goods on the trolleys 38 which are Imoved through the kiln from left to right in terms of the FIG. 3.
  • reference numeral 34 generally indicates the raised portion of the tunnel kiln roof over the last three burners as is shown in longitudinal section in FIG. 3 and also FIG. 2.
  • Reference numeral 37 indicates the burners arranged under the raised portion of the tunnel roof, while reference numeral 32 denotes those burners which are approximately at the same level as thevcarrying plat. forms of the trolleys.
  • Reference numeral 38 denotes the trolley while reference numeral 36 denotes the goods to be fired.
  • FIG. 5 differs from that shown in FIG. 4 only in that the roof of the tunnel kiln is vaulted.
  • the raised part of the tunnel roof over the last three burners of the burning zone is in this case denoted by reference numeral 34a.-
  • the remaining reference numerals correspond to those of FIG. 4.
  • the raised portion of the tunnel kiln roof is over the last three burners in the burning zone B and ends immediately after the last burner.
  • this prescription need not be preciselyadhered to and there isV some latitude as regards the number of burners over which the raised portion extends.
  • the necessary length of the raised portion depends onVv the dimensions ofthe tunnelk kiln and from the operational conditions. l
  • the raised portion of the roof it is not necessary in all cases to cause the raised portion of the roof to end immediately above the last burner. In some cases it may be advantageous to continue the raised portion beyond the last burner. In other cases, on the other hand, it may be appropriate to cause the raised portion of the roof to end before the last burner. In each case, however, the raised portion of the kiln roof must lie in the downstream part of the firing zone, that is to say downstream in relation to the direction of travel of the goods to be fired. It should be in the downstream half of the firing length.
  • the term ring zone or length is used to mean that length of the tunnel kiln which extends from the rst to the last laterally arranged burners at the bottom part of the articles to be red.
  • a tunnel kiln heated by uid fuel and serving for tiring ceramic articles having a horizontally extending tunnel, with a roof, in which burner means are placed for maintaininga ring length vor zonel in the tunnel of the kiln, the tiring zone being preceded by a heating-up length and followed by a cooling length, trolleys arranged to move along the kiln tunnel through the heating-up length, the firing length and the cooling length, the kiln atmosphere being arranged to move along the tunnel, in a direction opposite to the direction of travel of the trolleys, from the cooling length into the firing length and thence into the heating-up length, the invention which consists in that the tunnel roof at the downstream end of the firing is at a higher level than in the rest of the firing length.
  • the kiln including a horizontally extending tunnel with a roof, said tunnel having in seriatim a heat-up zone, a firing zone, and a cooling zone, and trolleys arranged to move along the kiln tunnel serially through said zones with the kiln atmosphere moving in the opposite direction, the invention which comprises:
  • burner means positioned longitudinally along the floor of said firing zone for heating said articles as they pass through said zone above said burner means; and a channel shaped recess in the tunnel roof extending from approxi-mately the downstream end of the firing zone to no further than midpoint of said zone for directing the longitudinally moving kiln atmosphere upwardly to permit the heat from said burner means to rise, approximately vertically to heat said articles throughout the tiring zone.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Tunnel Furnaces (AREA)
  • Furnace Details (AREA)
US723987A 1967-04-25 1968-04-25 Tunnel kilns with roof Expired - Lifetime US3494601A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEF0052241 1967-04-25

Publications (1)

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US3494601A true US3494601A (en) 1970-02-10

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Country Status (3)

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US (1) US3494601A (fr)
FR (1) FR1567348A (fr)
NL (1) NL6805814A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5293410A (en) * 1976-02-02 1977-08-05 Takasago Kogyo Kk Truck type tunnel furnace
US20130145640A1 (en) * 2011-12-07 2013-06-13 Samsung Electronics Co., Ltd. Apparatus and methods for treating a substrate

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US832358A (en) * 1906-10-02 Filip John Bergendal Furnace for calcining or burning briquets of ore.
US1529755A (en) * 1921-08-19 1925-03-17 Appareils Manutention Fours Stein Sa Tunnel furnace
DE943511C (de) * 1951-05-26 1956-05-24 Wistra Ofenbaugesellschaft M B Tunneloefen zum Brennen keramischen Gutes

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US832358A (en) * 1906-10-02 Filip John Bergendal Furnace for calcining or burning briquets of ore.
US1529755A (en) * 1921-08-19 1925-03-17 Appareils Manutention Fours Stein Sa Tunnel furnace
DE943511C (de) * 1951-05-26 1956-05-24 Wistra Ofenbaugesellschaft M B Tunneloefen zum Brennen keramischen Gutes

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5293410A (en) * 1976-02-02 1977-08-05 Takasago Kogyo Kk Truck type tunnel furnace
JPS5514353B2 (fr) * 1976-02-02 1980-04-15
US20130145640A1 (en) * 2011-12-07 2013-06-13 Samsung Electronics Co., Ltd. Apparatus and methods for treating a substrate
US9534839B2 (en) * 2011-12-07 2017-01-03 Samsung Electronics Co., Ltd. Apparatus and methods for treating a substrate
US10361100B2 (en) 2011-12-07 2019-07-23 Samsung Electronics Co., Ltd. Apparatus and methods for treating a substrate

Also Published As

Publication number Publication date
DE1558044B2 (de) 1971-11-25
FR1567348A (fr) 1968-05-16
NL6805814A (fr) 1968-10-28
DE1558044A1 (de) 1970-05-06

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