WO2007141365A1 - Drum dryer - Google Patents

Drum dryer Download PDF

Info

Publication number
WO2007141365A1
WO2007141365A1 PCT/FI2006/000181 FI2006000181W WO2007141365A1 WO 2007141365 A1 WO2007141365 A1 WO 2007141365A1 FI 2006000181 W FI2006000181 W FI 2006000181W WO 2007141365 A1 WO2007141365 A1 WO 2007141365A1
Authority
WO
WIPO (PCT)
Prior art keywords
drum
drum dryer
fastened
support parts
shell part
Prior art date
Application number
PCT/FI2006/000181
Other languages
French (fr)
Inventor
Ari Männikkö
Jarno Hietala
Original Assignee
Metso Panelboard Oy
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 Metso Panelboard Oy filed Critical Metso Panelboard Oy
Priority to PCT/FI2006/000181 priority Critical patent/WO2007141365A1/en
Publication of WO2007141365A1 publication Critical patent/WO2007141365A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B11/00—Machines or apparatus for drying solid materials or objects with movement which is non-progressive
    • F26B11/02—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles
    • F26B11/04—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis
    • F26B11/0463—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis having internal elements, e.g. which are being moved or rotated by means other than the rotating drum wall
    • F26B11/0477—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in moving drums or other mainly-closed receptacles rotating about a horizontal or slightly-inclined axis having internal elements, e.g. which are being moved or rotated by means other than the rotating drum wall for mixing, stirring or conveying the materials to be dried, e.g. mounted to the wall, rotating with the drum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B2210/00—Drying processes and machines for solid objects characterised by the specific requirements of the drying good
    • F26B2210/16—Wood, e.g. lumber, timber

Definitions

  • This invention relates to a drum dryer and to be precise the internal structure of a drum dryer to be used in drying fibres, such as e.g. chips.
  • Drying of chips is required in manufacturing chipboards, OSB boards or similar in order to evaporate excess moisture from the raw material e.g. wood (chips) and in order to obtain a desired, low enough moisture level for the chips. Drying time depends on the initial moisture content of the material to be dried but also on the wood species used and the thickness of the chip etc.
  • outer-layer particles and middle-layer particles must have a correct and even level of moisture.
  • the drying of chips is thus a substantial and very important stage in manufacturing chipboards or similar.
  • drum dryers For drying chips are commonly used drum dryers including a rotating drum part in which the chips to be dried are rotated, mixed and conveyed forward. Inside the drum, there are members which mix the chips and which also function as drying profiles because of the contact between the chip and the hot mixing member.
  • Drum dryers are known for drying fibres, such as chips, in which dryers an often grid-like or radial structure which carries mixing members i.e. drying profiles is fastened either by welding or with screw couplings to the shell of the drum dryer.
  • different structures or components are in different temperatures.
  • the temperature differences are especially high.
  • the shell part of the drum heats up considerably more slowly than the internal structures of the drum.
  • the thin parts of the internal structures heat up and cool down more quickly in the gas flow than parts manufactured of a thicker material. High stresses/stress peaks tend to be created to the structure because of thermal movement which stresses weaken the fatigue durability of the structure.
  • stress is created from the mass of the parts of the dryer drum itself and from the mass of the chips to be dried.
  • the stresses of the structure of the rotating drum dryer should remain low mainly because of an alternating load caused by temperature differences and rotation. Stress is especially caused to the drum shell and the parts which carry drying profiles and to the dryer profiles themselves. Because of stresses created, quite large breaks and cracks occur commonly in the structures and their seams/welded seams, and the structures of the drum can also totally "fail” because of this. This frequently causes an interruption in the drying process. Repairing welded seams or similar is difficult and also then a time-consuming measure because of high temperatures in the drum and the narrowness of the drum which is caused by the structures inside the drum.
  • the object of this invention is thus to provide a drum dryer in which the thermal movement caused by temperature differences or the deformation of the drum shell or also the deflection caused by the weight of the structures themselves or the material to be dried does not cause too high stresses in the internal structures of the drum nor their fastening points.
  • the apparatus according to the invention is characterised by the support parts of the dryer profiles having been fastened pivotedly or flexibly in respect of the shell part of the drum dryer.
  • drum dryer according to the invention is characterised by what is stated in the accompanying claims 2-6.
  • the now presented device according to the invention has some considerable advantages compared to known solutions.
  • the drum structure according to the invention eliminates practically totally the increase of stresses caused by thermal movements seen in the direction of both the radius of the drum and the longitudinal axle of the drum. Because of this, the structures in the drum and the seam/connection points of the structures endure essentially better and longer in the drum dryer according to the invention compared to conventional drum dryers used today. For this reason, also the operating reliability and the durability of the drum dryer are improved, the need for maintenance decreases and the operating life increases considerably.
  • Figs. 1a and 1 b show a cross section as a side view of a drum dryer according to a known solution with its internal structures.
  • Figs. 2a and 2b show the structure and operating principle of a drum dryer according to the invention.
  • Fig. 3a shows a situation in which there is no temperature difference between the shell and the support parts of the drum dryer according to the invention.
  • Fig. 3b shows a situation in which the temperature of the support parts of the drum dryer according to the invention is higher than the temperature of the shell parts of the drum.
  • Fig. 4 shows a cross section of a drum dryer according to the invention.
  • Figs. 1a and 1b show a cross section as a side view of a drum dryer according to a known solution with its internal structures. Drying profiles 7 are installed to several zones 9. Grid-like support structures 10 carrying the drying profiles from their ends are fastened by welding to the shell of the drum dryer.
  • Figs. 2a and 2b show the structure and operating principle of a drum dryer according to the invention.
  • Fig. 2a on the inner surface of the shell part of the rotating drum are fastened support parts which endure thermal expansions caused by temperature changes by means of pivotings 5 and 5' in them.
  • Fig. 2a shows support parts 3 and 4 of the rotating drum
  • Fig. 2b shows the same parts when the drum has rotated 180 degrees.
  • Thermal expansion causes the support parts 3 and 4 to extend and an angular change in points A, B and C caused by it.
  • the angular change in points B and C is caused by a deflection in the support part 4 caused by the mass of the support parts themselves.
  • the support parts 3, 4 are pivoted in points A, B and C, whereby no moment caused by the angular change occurs in the support parts and on the shell.
  • Fig. 3 shows a situation in which the temperature of the support parts 3, 4 is higher than the temperature of the shell part 2 of the drum, whereby rotation takes place from pivot points 5, 5 ' .
  • the structure is also flexible in a situation in which the shell part 2 of the drum would for some reason be deformed.
  • Fig. 3 shows a cross section of the drum dryer.
  • the drum has the shell part 2, the support parts 3, 4 fastened to the shell part and the drying profiles 7, 8 fastened to the support part.
  • the support parts of the drying profiles are fastened directly or indirectly in respect of the shell part of the drum pivotedly 5 or flexibly.
  • At least two or more support parts are fastened pivotedly with each other, with the pivot 5 ' .
  • the pivoting 5 of the support parts is on the internal surface of the shell part 2, or the pivoting 5 of the support part is in a protrusion, projection or similar (not shown in the figure) in the shell part.
  • Fig. 4 shows according to the invention the grid-like support structures 10 of Fig. 1 b fastened rigidly to the drum shell e.g. by welding having been replaced by the support parts 3, 4 according to Fig. 3 fastened by means of the pivots 5, 5'. It is well known by those skilled in the art that the different embodiments of the invention are not solely limited to the examples described above, and thus they may vary within the scope of the appended claims.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

A drum dryer for drying chips used in manufacturing chipboards, OSB boards or similar, which drum dryer has a shell part and support parts fastened to the shell part, and drying profiles fastened to the support part, and in which the support parts of the drying profiles are fastened pivotedly or flexibly in respect of the shell part of the drum dryer.

Description

DRUM DRYER
Background of the invention
This invention relates to a drum dryer and to be precise the internal structure of a drum dryer to be used in drying fibres, such as e.g. chips.
Drying of chips is required in manufacturing chipboards, OSB boards or similar in order to evaporate excess moisture from the raw material e.g. wood (chips) and in order to obtain a desired, low enough moisture level for the chips. Drying time depends on the initial moisture content of the material to be dried but also on the wood species used and the thickness of the chip etc.
Especially when pressing above-mentioned boards, outer-layer particles and middle-layer particles must have a correct and even level of moisture. In the press stage, it is almost impossible to correct errors caused by excess moisture. The drying of chips is thus a substantial and very important stage in manufacturing chipboards or similar.
For drying chips are commonly used drum dryers including a rotating drum part in which the chips to be dried are rotated, mixed and conveyed forward. Inside the drum, there are members which mix the chips and which also function as drying profiles because of the contact between the chip and the hot mixing member.
Inside the drum there is quite a high temperature (obtained e.g. by sucking hot drying gas to the drum by means of a blower or some other way) for evaporating water in the chips. There can exist temperatures of several hundreds of degrees
Celsius inside the drum.
Drum dryers are known for drying fibres, such as chips, in which dryers an often grid-like or radial structure which carries mixing members i.e. drying profiles is fastened either by welding or with screw couplings to the shell of the drum dryer. Inside the drum dryer, different structures or components are in different temperatures. When starting up and running down the drying process, the temperature differences are especially high. E.g. the shell part of the drum heats up considerably more slowly than the internal structures of the drum. The thin parts of the internal structures heat up and cool down more quickly in the gas flow than parts manufactured of a thicker material. High stresses/stress peaks tend to be created to the structure because of thermal movement which stresses weaken the fatigue durability of the structure. Furthermore, stress is created from the mass of the parts of the dryer drum itself and from the mass of the chips to be dried. The stresses of the structure of the rotating drum dryer should remain low mainly because of an alternating load caused by temperature differences and rotation. Stress is especially caused to the drum shell and the parts which carry drying profiles and to the dryer profiles themselves. Because of stresses created, quite large breaks and cracks occur commonly in the structures and their seams/welded seams, and the structures of the drum can also totally "fail" because of this. This frequently causes an interruption in the drying process. Repairing welded seams or similar is difficult and also then a time-consuming measure because of high temperatures in the drum and the narrowness of the drum which is caused by the structures inside the drum.
The object of this invention is thus to provide a drum dryer in which the thermal movement caused by temperature differences or the deformation of the drum shell or also the deflection caused by the weight of the structures themselves or the material to be dried does not cause too high stresses in the internal structures of the drum nor their fastening points.
Brief description of the invention
The apparatus according to the invention is characterised by the support parts of the dryer profiles having been fastened pivotedly or flexibly in respect of the shell part of the drum dryer.
In addition, the drum dryer according to the invention is characterised by what is stated in the accompanying claims 2-6.
The now presented device according to the invention has some considerable advantages compared to known solutions. The drum structure according to the invention eliminates practically totally the increase of stresses caused by thermal movements seen in the direction of both the radius of the drum and the longitudinal axle of the drum. Because of this, the structures in the drum and the seam/connection points of the structures endure essentially better and longer in the drum dryer according to the invention compared to conventional drum dryers used today. For this reason, also the operating reliability and the durability of the drum dryer are improved, the need for maintenance decreases and the operating life increases considerably. Brief description of the figures
The invention will now be described in more detail by means of examples with reference to the accompanying drawings, in which
Figs. 1a and 1 b show a cross section as a side view of a drum dryer according to a known solution with its internal structures.
Figs. 2a and 2b show the structure and operating principle of a drum dryer according to the invention.
Fig. 3a shows a situation in which there is no temperature difference between the shell and the support parts of the drum dryer according to the invention.
Fig. 3b shows a situation in which the temperature of the support parts of the drum dryer according to the invention is higher than the temperature of the shell parts of the drum.
Fig. 4 shows a cross section of a drum dryer according to the invention.
Detailed description of the invention
Figs. 1a and 1b show a cross section as a side view of a drum dryer according to a known solution with its internal structures. Drying profiles 7 are installed to several zones 9. Grid-like support structures 10 carrying the drying profiles from their ends are fastened by welding to the shell of the drum dryer.
Figs. 2a and 2b show the structure and operating principle of a drum dryer according to the invention.
According to Fig. 2a, on the inner surface of the shell part of the rotating drum are fastened support parts which endure thermal expansions caused by temperature changes by means of pivotings 5 and 5' in them. Fig. 2a shows support parts 3 and 4 of the rotating drum, and Fig. 2b shows the same parts when the drum has rotated 180 degrees. Thermal expansion causes the support parts 3 and 4 to extend and an angular change in points A, B and C caused by it. Additionally, in the case of the figure, the angular change in points B and C is caused by a deflection in the support part 4 caused by the mass of the support parts themselves. The support parts 3, 4 are pivoted in points A, B and C, whereby no moment caused by the angular change occurs in the support parts and on the shell. Then, the only factor causing stresses is the load caused by the mass of the structure itself. Thermal movement is free irrespective of temperature, whereby stresses are minimised, and whereby the life of the structure is considerably longer than that of a rigidly fastened structure in which the support parts were e.g. welded on the shell part.
Fig. 3 shows a situation in which the temperature of the support parts 3, 4 is higher than the temperature of the shell part 2 of the drum, whereby rotation takes place from pivot points 5, 5'. The structure is also flexible in a situation in which the shell part 2 of the drum would for some reason be deformed.
Fig. 3 shows a cross section of the drum dryer. The drum has the shell part 2, the support parts 3, 4 fastened to the shell part and the drying profiles 7, 8 fastened to the support part.
The support parts of the drying profiles are fastened directly or indirectly in respect of the shell part of the drum pivotedly 5 or flexibly.
At least two or more support parts are fastened pivotedly with each other, with the pivot 5'.
The pivoting 5 of the support parts is on the internal surface of the shell part 2, or the pivoting 5 of the support part is in a protrusion, projection or similar (not shown in the figure) in the shell part.
Several support parts are fastened to the shell part of the drum, and the support parts are pivoted from their one end to other support parts. The drying profiles 7, 8 are fastened to the support parts so that they are able to move in the direction of the drum axle, whereby they do not cause stresses to the support parts e.g. because of thermal extension.
Fig. 4 shows according to the invention the grid-like support structures 10 of Fig. 1 b fastened rigidly to the drum shell e.g. by welding having been replaced by the support parts 3, 4 according to Fig. 3 fastened by means of the pivots 5, 5'. It is well known by those skilled in the art that the different embodiments of the invention are not solely limited to the examples described above, and thus they may vary within the scope of the appended claims.

Claims

1. A drum dryer (1 ) for drying chips used in manufacturing chipboards, OSB boards or similar, which drum dryer has a shell part (2) and support parts
(3, 4) fastened to the shell part, and drying profiles (7, 8) fastened to the support part, characterised in that the support parts of the drying profiles are fastened pivotedly (5) or flexibly in respect of the shell part of the drum dryer.
2. A drum dryer according to claim 1 , characterised in that at least two support parts are fastened pivotedly (5') with each other.
3. A drum dryer according to claim 1 , characterised in that the pivoting (5) of the support parts is on the internal surface of the shell part.
4. A drum dryer according to claim 1 , characterised in that the pivoting (5) of the support parts is in a projection or similar in the shell part.
5. A drum dryer according to claim 1 , characterised in that the drying profiles (7, 8) are fastened to one support part so that they are able to move in the longitudinal direction of the shell part (2).
6. A drum dryer according to claim 1 , characterised in that the drying profiles (7, 8) are fastened to two or more support parts so that they are able to move in the direction of the axle of the drum dryer.
PCT/FI2006/000181 2006-06-07 2006-06-07 Drum dryer WO2007141365A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/FI2006/000181 WO2007141365A1 (en) 2006-06-07 2006-06-07 Drum dryer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/FI2006/000181 WO2007141365A1 (en) 2006-06-07 2006-06-07 Drum dryer

Publications (1)

Publication Number Publication Date
WO2007141365A1 true WO2007141365A1 (en) 2007-12-13

Family

ID=38801088

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI2006/000181 WO2007141365A1 (en) 2006-06-07 2006-06-07 Drum dryer

Country Status (1)

Country Link
WO (1) WO2007141365A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104990380A (en) * 2015-07-23 2015-10-21 福建南方路面机械有限公司 Aggregate drying drum and drying method for dry-mixed mortar production line

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1246588B (en) * 1961-07-07 1967-08-03 Prep Ind Combustibles Drying drum, especially for coal sludge
US3576080A (en) * 1969-11-19 1971-04-27 Allis Chalmers Mfg Co Rotary cooler and the like
FI890408A (en) * 1989-01-27 1990-06-29 Raute Oy CYLINDERTORK.
US5338188A (en) * 1990-03-19 1994-08-16 Cedarapids, Inc. Radiant heat rotary volatilizer
FI20031304A (en) * 2003-09-11 2005-03-12 Konepaja Kopar Oy drying Unit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1246588B (en) * 1961-07-07 1967-08-03 Prep Ind Combustibles Drying drum, especially for coal sludge
US3576080A (en) * 1969-11-19 1971-04-27 Allis Chalmers Mfg Co Rotary cooler and the like
FI890408A (en) * 1989-01-27 1990-06-29 Raute Oy CYLINDERTORK.
US5338188A (en) * 1990-03-19 1994-08-16 Cedarapids, Inc. Radiant heat rotary volatilizer
FI20031304A (en) * 2003-09-11 2005-03-12 Konepaja Kopar Oy drying Unit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104990380A (en) * 2015-07-23 2015-10-21 福建南方路面机械有限公司 Aggregate drying drum and drying method for dry-mixed mortar production line
CN104990380B (en) * 2015-07-23 2018-08-10 福建南方路面机械有限公司 Aggregate drying roller and furnace drying method for dry-mixed mortar production line

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