US3703277A - Cooling apparatus for the outlet of a rotary kiln - Google Patents

Cooling apparatus for the outlet of a rotary kiln Download PDF

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Publication number
US3703277A
US3703277A US111930A US3703277DA US3703277A US 3703277 A US3703277 A US 3703277A US 111930 A US111930 A US 111930A US 3703277D A US3703277D A US 3703277DA US 3703277 A US3703277 A US 3703277A
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US
United States
Prior art keywords
kiln
outlet
tubes
cylinder
annular
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Expired - Lifetime
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US111930A
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English (en)
Inventor
Ulrich Walter Bosshard
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Holderbank Management and Consulting Ltd
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Holderbank Management and Consulting Ltd
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Publication date
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    • 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
    • F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
    • F27B7/20—Details, accessories or equipment specially adapted for rotary-drum furnaces
    • F27B7/22—Rotary drums; Supports therefor
    • F27B7/224—Discharge ends
    • 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
    • F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
    • F27B7/20—Details, accessories or equipment specially adapted for rotary-drum furnaces
    • F27B7/38—Arrangements of cooling devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/0275—Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores

Definitions

  • the means preferably includes an annular [58] Field 01 Search ..263/33, 44; 165/105 portion which extends radially inward from the ends R f d of the tubes and adjacent to the end face of the kiln [5 6] e erences outlet to protect the face from heat radiating from the UNITED STATES PATENTS kiln.
  • the annular member is preferably segmented and l 238 394 8/1917 Eld d 263/44 is made of a thermally conductive material.
  • the last axial outlet end portion in modern kilns generally consists of heat-resistant steel segments which are provided relatively to one another and relatively to the outlet end face of the shell plating, for constructional reasons, with a clearance which also varies with the thermal expansion phenomena occurring, and this additionally results in cooling air passing from the annular gap into the kiln.
  • the air cooling achieved has not kept up with the high thermal loads which can be expected nowadays at a kiln outlet end.
  • an outlet end portion of a rotary kiln is so constructed according to the invention that externally on the cylinder shell there are arranged, distributed uniformly over the periphery, boiler tubes which contain a liquid for boiling, the said tubes being connected for conduction of heat to the cylinder shell over a relatively short axial outlet end portion and over the remaining axial portion adjoin the surrounding atmosphere, the arrangement being such that when the said liquid is acted upon by heat from the kiln it is evaporated in the hot region of the boiler tubes corresponding to the aforesaid axial outlet end portion and is condensed in the cold region giving up heat to the surrounding atmosphere.
  • annular disc of a material which is a good conductor of heat there is arranged at the outlet side of the outlet end face of the cylinder shell an annular disc of a material which is a good conductor of heat, the said disc being coaxial with the cylinder axis and occupying at least the radial extent of the cylinder shell, the said disc being connected to the outlet-side ends of the boiler tubes in thermally conducting manner and being arranged to be thermally insulated relatively to the end face of the cylinder shell.
  • the aforesaid annular disc is preferably sub-divided into a number of ring segments corresponding to the number of boiler tubes, the said segments covering the boiler tubes radially.
  • a further feature consists in that the annular component with which the outlet-side ends of the boiler tubes are connected, i.e. the outlet-side end of the cylinder shell or the annular disc, comprises cavities which open towards the kiln end.
  • the axes of the cavities extend substantially parallel to the cylinder axis and contain heat-insulating material.
  • the boiler tubes comprise, in their cold portion, means for increasing the surface area adjoining the environment.
  • a further feature consists in that a annular duct is provided which surrounds the cylinder and is connected to a source of cooling air and comprises an annular nozzle.
  • the axes of the annular nozzle cross-section intersect the 'cylinder axis at a point and being situated on a cone coaxial with the cylinder, whose apex coincides with the aforesaid point of intersection and whose base is situated at the outlet side of the cone apex.
  • the nozzle axes intersect the axes of the boiler tubes in the cold portion thereof.
  • the annular duct is advantageously connected to the cylinder-side portion of the kiln end, and at the outlet region of the annular nozzle there is arranged in the annular space radially bounded by the cylinder shell and the annular duct at least one sealing rib which bounds an annular gap with that wall of the annular duct which is nearest the cylinder shell, or with the cylinder shell.
  • FIG. 1 shows a view of the outlet end portion of a rotary kiln of cylindrical type with the kiln end shown in section, for the production of cement clinker
  • FIG. 2 shows a detail from FIG. 1 on a larger scale
  • FIG. 3 shows in fragmentary form an axial section through a modified form of the rotary kiln outlet on a larger scale
  • FIG. 4 shows a view in the direction of the arrow Z in FIG. 3,
  • FIGS. 5 and 6 each show fragmentary views in the axial direction of an end portion of a rotary kiln cylinder of a different constructional form on a larger scale
  • FIG. 7 shows an axial section through a fragmentary portion of another rotary kiln.
  • FIG. 1 shows the outlet-side end of a rotary kiln cylinder having the cylinder shell I, the outermost race ring 2, a visible bearing roller 3 and a toothed annulus 4 for driving the cylinder.
  • the axis 5 of the cylinder is inclined by for example 3 percent relatively to the horizontal foundation 6.
  • 7 designates the kiln end and 8 the fuel nozzle.
  • FIGS. 3,4, and 7 show the refractory brickwork 9 within the cylinder shell 1.
  • boiler tubes 12 Provided externally on the cylinder shell 1, distributed uniformly over the periphery and approximately parallel to the cylinder axis 5, are closed boiler tubes 12 containing a liquid for boiling 11, these tubes slightly projecting beyond the outlet end face 10 of the cylinder shell. These tubes, are connected in thermally conductive manner to the cylinder shell 1 over a relatively short axial outlet end portion 13. Over the remaining axial portion the boiler tubes 12 are in contact with the atmosphere. When subjected to heat from the kiln, the liquid in the hot region of the boiler tubes 12 corresponding to the axial outlet end portion 13 evaporates and is condensed in the cold region 14 giving up heat to the atmosphere.
  • the boiler tubes 12 are inclined by 1.5 percent relatively to the generatrices 55 of the cylinder shell 1, converging towards the outlet of the cylinder.
  • the gap formed by this inclination is filled with weld metal 15 in the short axial portion 13, and the thermally conductive connection is achieved by welding.
  • FIG. 3 shows that the cylinder shell 1 is of reduced thickness over the outermost axial portion. This known measure, forming a step, is advantageously used for giving the boiler tubes the desired inclination relatively to the cylinder axis.
  • the axial portion 13 amounts for example to about cm and the entire length of a boiler tube 12 for example 3 m to 4 m.
  • the dimensions and number of the boiler tubes and also the properties of the liquid used for boiling are adapted to the amount of heat which has to be discharged, the temperature of the environment and the surface area of the boiler tubes.
  • the cold region 14 of the boiler tubes 12 comprises ribs 16 for increasing the surface area bordering on the environment; it is also possible to use corrugated strips, spikes or the like.
  • the boiler tube 12 situated at the top of the cylinder shell, as FIG. 2 shows is inclined by 4.5 percent relatively to the horizontal or the surface level 66 of the liquid 11, and the lowermost boiler tube situated at the underside of the cylinder shell is inclined by 1.5 percent relatively to the horizontal, or the surface level of the liquid.
  • the boiler tubes may be arranged parallel to the cylinder axis. However, whether the boiler tubes are inclined relatively to the cylinder axis and at what inclination they should be inclined depends on the inclination of the cylinder axis relatively to the horizontal, the construction of the outer surface of the cylinder shell, and the space available, and had nothing to do with the essential matter of the invention.
  • annular disc 17 of a material constituting a good conductor of heat, which disc is coaxial with the drum axis 5 and extends radially inwards over the end surface of the cylinder shell and radially outward to the radially outer points of the boiler tubes 12.
  • This annular disc 17 is connected in thermally conductive manner to the outlet end portions of the boiler tubes.
  • the annular disc 17 is arranged in thermally insulated manner, these parts being spaced at a small axial distance from one another. This spacing is shown exaggeratedly large in the drawings for the sake of easier reading. At all events, the clearance of about 2 mm which always occurs for manufacturing reasons between the two parts would be sufficient for thermal insulation, and individual local points of contact would not produce any considerable flow of heat.
  • FIG. 5 shows the outlet end face 10 of a cylinder shell 1 and also the outlet-end cover 19 of a boiler tube 12, and also its connecting weld 15 with the cylinder shell.
  • the portion of the cylinder shell connected to the outlet ends of the boiler tubes comprises cavities 20 which are open towards the kiln end and have axes parallel to the cylinder axis, these cavities accommodating heat-insulating ceramic material 21.
  • the cavities 20 are preferably drilled.
  • an annular disc 17 is shown which has ring segments 18 which are connected to the outlet ends of the boiler tubes 12.
  • the ring segments 18 extend radially outwardly to cover the boiler tubes 12.
  • honeycomb cells 22 which define cavities 23 which are open towards the kiln head 7 and have axes parallel to the cylinder axis and which accommodate heat-insulating ceramic material 21.
  • the walls of the cells are preferably cast in one piece with the ring segments.
  • the rotary kiln shown in FIG. 7 comprises an annular duct 25 which surrounds the cylinder, is connected to a cooling air fan 24, and has an annular nozzle 26, the axes 27 of the annular nozzle cross-sections intersecting the cylinder axis 5 at one point and being situated on a cone coaxial with the cylinder whose apex coincities with the aforesaid point of intersection and whose base is situated at the outlet side of the cone apex, and that the nozzle axes intersect the axes of the boiler tubes 12 in the cold region 14 thereof.
  • the annular duct 25 is connected to the outlet-side portion of the kiln end 7, and at the outlet side of the annular nozzle 26 there are arranged in the annular space bounded radially by the cylinder shell 1 and the annular duct 25 two sealing ribs 28 which in each case bound an annular gap with that wall of the annular duct 25 which is nearest the cylinder shell. In this way a pressure cushion of cooling air is built up at the sides of the sealing ribs 28 remote from the outlet. This pressure cushion and also the impulse of the cooling air issuing from the annular nozzle insure that no cooling air will enter the kiln end 7.
  • Cooling apparatus for the outlet of a rotary kiln of the type including a cylindrical shell (1) having an inner refractory lining (9) characterized in that a plurality of closed boiler tubes are mounted externally on the cylindrical shell, the tubes being uniformly distributed over the periphery of the shell and at least approximately parallel with the cylinder axis (5), said tubes containing a liquid (11) for boiling and having their ends substantially in alignment with the outletside end face of the cylindrical shell, which ends are connected in thermally conductive manner to the cylindrical shell over a relatively short axial end portion (13), the remaining axial portion of the tubes being in contact with the environment whereby liquid in said ends absorbs heat from the kiln and is vaporized and said vapor condenses in said remaining axial portion giving up heat to the environment, the condensate in each tube being returned to its said end.
  • Cooling apparatus according to the claim 1, further characterized in that at the outlet side of the outlet end face (10) of the cylinder shell (1) there is arranged an annular disc (17) of a thermally conductive material which is coaxial with the cylinder axis (5), occupies at least the radial extent of the cylindrical shell, the disc being connected in thermally conductive manner to said ends of the boiler tubes (12) and arranged so as to be thermally insulated relatively to the end face (10) of the cylinder shell (1 3.
  • Cooling apparatus characterized in that the annular disc (17) is sub-divided into a number of ring segments (18) corresponding to the number of boiler tubes (12), the said segments extending radially across said ends of the boiler tubes.
  • Cooling apparatus characterized in that the end face (10) to which said ends of the boiler tubes (12) are connected, comprises cavities (20) which are open toward the kiln end (7) and have axes substantially parallel with the cylinder axis; and heat-insulating material (21) received in said cavities.
  • Cooling apparatus further characterized in that said disc (17) comprises cavities 23 which are open toward the kiln end (7) and having axes substantially parallel with the cylinder axis; and heat insulating material received in said cavities.
  • Cooling apparatus according to claim 1, further characterized in that the boiler tubes (12) include over at least a part of said remaining portions, means (16) for increasing the surface area exposed of the environment.
  • Cooling apparatus according to claim 1, further characterized in that an annular duct (25) surrounds the cylinder, and is connected to a cooling air source (24) and which includes an annular nozzle (26), the axes (27) of the annular nozzle cross-sections intersecting the cylinder axis (5) at a point and being situated on a cone which is coaxial with the cylinder, whose apex coincides with said point of intersection and whose base is situated at the outlet side of the cone apex, and in that said nozzle axes (27 intersect the axes of the boiler tubes (12) in a cold region (14) thereof.
  • annular duct encircles the shell near the outlet end of the kiln and defines together with said shell an annular gap; at least one radial sealing rib extending from one boundary wall of said gap toward another boundary wall of said gap.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
US111930A 1970-02-04 1971-02-02 Cooling apparatus for the outlet of a rotary kiln Expired - Lifetime US3703277A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH155970A CH512045A (de) 1970-02-04 1970-02-04 Kühlvorrichtung für den Auslauf eines Drehtrommelofens

Publications (1)

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US3703277A true US3703277A (en) 1972-11-21

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US111930A Expired - Lifetime US3703277A (en) 1970-02-04 1971-02-02 Cooling apparatus for the outlet of a rotary kiln

Country Status (8)

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US (1) US3703277A (enExample)
JP (1) JPS4933386B1 (enExample)
CA (1) CA934157A (enExample)
CH (1) CH512045A (enExample)
DE (1) DE2103475B2 (enExample)
DK (1) DK127306B (enExample)
FR (1) FR2080461A5 (enExample)
GB (1) GB1331721A (enExample)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4707175A (en) * 1985-12-23 1987-11-17 Ppg Industries, Inc. Method of preheating pulverulent batch material
US4836775A (en) * 1985-12-23 1989-06-06 Ppg Industries, Inc. Air cooled rotary kiln collar
US4889060A (en) * 1989-01-27 1989-12-26 Westinghouse Electric Corp. Web for rotary combustor
US5711664A (en) * 1995-08-03 1998-01-27 Commissariat A L'energie Atomique Rotary melting furnace

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55131686A (en) * 1979-03-30 1980-10-13 Hitachi Ltd Installation of heat pipe
DE3534991A1 (de) * 1985-10-01 1987-04-02 Gutehoffnungshuette Man Drehrohrkuehler

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4707175A (en) * 1985-12-23 1987-11-17 Ppg Industries, Inc. Method of preheating pulverulent batch material
US4836775A (en) * 1985-12-23 1989-06-06 Ppg Industries, Inc. Air cooled rotary kiln collar
US4889060A (en) * 1989-01-27 1989-12-26 Westinghouse Electric Corp. Web for rotary combustor
US5711664A (en) * 1995-08-03 1998-01-27 Commissariat A L'energie Atomique Rotary melting furnace

Also Published As

Publication number Publication date
FR2080461A5 (enExample) 1971-11-12
DK127306B (da) 1973-10-15
JPS46840A (enExample) 1971-09-04
DE2103475A1 (de) 1971-08-19
JPS4933386B1 (enExample) 1974-09-06
DE2103475B2 (de) 1972-01-05
CH512045A (de) 1971-08-31
CA934157A (en) 1973-09-25
GB1331721A (en) 1973-09-26

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