Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F5/00—Dryer section of machines for making continuous webs of paper
  • D21F5/02—Drying on cylinders
  • D21F5/022—Heating the cylinders
  • D21F5/027—Heating the cylinders using a heat-transfer fluid between the heating means and the cylinder shell

Definitions

• the invention relates to a drying cylinder for drying a paper, board, tissue or another fibrous web in a machine for producing and / or finishing the same with a carrier body and an outer jacket layer which is heated by a hot fluid.
• drying arrangements with such drying cylinders have long been known, the fibrous web, which, supported by a drying wire, wraps around.
• the contact of the fibrous web with the hot jacket surface causes the heating and, in particular, after the removal from the drying cylinder to evaporate.
• the drying rate is essentially limited by the jacket thickness and thus the thermal resistance of the drying cylinder.
• the object of the invention is therefore to increase the heat flow through the outer cladding layer.
• this object is achieved in that between the support body and the outer cladding layer at least one cavity is present, through which the fluid flows and the outer cladding layer is predominantly so thin that the quotient of the thermal conductivity of the material and the thickness of the outer cladding layer greater as a limit, for steel 3.2 kW / m 2 K, for aluminum - 2 -
• the support body preferably extends axially over the entire drying cylinder and ensures sufficient stability of the same. This leads to a substantial relief of the supporting function of the outer jacket layer, so that it can be made much thinner.
• the outer cladding layer must only support itself and absorb the internal pressure of the fluid in the cavity. Depending on the design and extent of the drying cylinder and the support of the outer cladding layer results in a minimum thickness for the outer cladding layer.
• the upper limit of the thickness of the cladding layer is determined by the o.g. Limit value given.
• the outer jacket layer should be supported by tie rods on the support body. This can about struts, partitions o.a. take place, with fixed or positive connections are possible.
• the support body carries an inner cladding layer, the like with the outer cladding layer via connecting elements such as webs, fins o.a. is connected, wherein the cavity between the outer and the inner cladding layer is formed.
• the fluid is vapor and the pressure in the cavity is preferably between 1, 5 and 13 bar, it will suffice to make the outer jacket layer with a thickness between 5 and 15 mm.
• Jacket layer of advantage these profiled inside, preferably grooved perform.
• the quotient should be outside the tie rods or fasteners above the corresponding limit and / or at more than 60%, preferably more than 75% of the outer surface of the outer cladding layer, the quotient at least on average greater than the corresponding limit.
• a preferred application of the heated drying cylinder results in addition to the replacement of conventional drying cylinders in drying arrangements for a fibrous web, in which at least one water-absorbing band wraps around the drying cylinder together with the fibrous web, the fibrous web comes into contact with the drying cylinder and another, outer, dense band is cooled in the wrap of the drying cylinder.
• the steam resulting from the heating of the fibrous web during contact with the heated drying cylinder passes into the water-absorbing ribbons surrounding the fibrous web when the drying cylinder is wrapped around. These tapes cause condensation and storage of the condensate.
• the dense band wraps around the drying cylinder, preventing steam from escaping.
• This dense band is usually cooled, so as to specify by the gain of the temperature gradient to the heated drying cylinder towards the direction of evaporation from the fibrous web and to enhance the condensation of the vapor.
• the fibrous web is pressed by a belt, preferably a dryer, with a strip tension of at least 10, preferably at least 20 kN / m on the outer surface of the drying cylinder.
• FIG 1 a schematic cross section through a drying cylinder 4, Figure 2. another drying cylinder 4 and
• Figure 3 a cross section through a drying arrangement.
• the essential feature of the drying cylinder 4 according to the invention is a very thin outer jacket layer 7, which is stabilized by a supporting body 8 of the drying cylinder 4.
• the quotient A of the thermal conductivity ⁇ and the jacket thickness s is greater than 3.2 kW / m 2 K.
• the thickness of the outer jacket layer 7 is therefore between 4 and 18 mm.
• the loss of stability compensates for the support body 8, which extends axially over the entire drying cylinder 4. - 5 -
• the vapor in the cavities has a pressure between 1, 5 and 10 bar and flows axially through the cavities 12.
• this cladding layer 7 has ribs 10 which protrude from the condensate layer.
• the support body 8 is formed as a thick-walled cylinder jacket, which limits the cavities 12 at the same time.
• the cavities 12 in Figure 2 are bounded by an inner 11 and an outer 7 cladding layer.
• As stabilizing connecting elements 6 between these cladding layers 7,11 sidewalls are used.
• the inner cladding layer 11 is supported by the support body 8.
• FIG. 3 shows a preferred application of the drying cylinder 4 in a drying arrangement in which the fibrous web 1, together with at least one water-absorbing band 2 and an outwardly dense band 3, wraps around the drying cylinder 4.
• the dense band 2 is cooled during the wrapping of a hood 5 with water.
• the heating of the fibrous web 1 during contact with the outer jacket layer 7 of the drying cylinder 4 leads to evaporation and condensation of the liquid in the water-absorbing belt 2. This is from - 6 -

Landscapes

• Drying Of Solid Materials (AREA)
• Paper (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=35708377

Family Applications (1)

Country Status (8)

Families Citing this family (9)

Family Cites Families (152)

• 2005
  • 2005-01-05 DE DE102005000782A patent/DE102005000782A1/de not_active Withdrawn
  • 2005-11-22 CN CNA2005800458771A patent/CN101094953A/zh active Pending
  • 2005-11-22 JP JP2007548796A patent/JP4633801B2/ja not_active Expired - Fee Related
  • 2005-11-22 WO PCT/EP2005/056151 patent/WO2006072507A1/de active Application Filing
  • 2005-11-22 EP EP05811125A patent/EP1838921A1/de not_active Withdrawn
  • 2005-11-22 RU RU2007129851/12A patent/RU2372434C2/ru not_active IP Right Cessation
  • 2005-11-22 BR BRPI0518106-2A patent/BRPI0518106A/pt not_active IP Right Cessation
• 2007
  • 2007-06-28 US US11/769,819 patent/US7802377B2/en not_active Expired - Fee Related
• 2010
  • 2010-09-21 JP JP2010210831A patent/JP2011047643A/ja active Pending

Non-Patent Citations (1)

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