Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/50—Spraying or projecting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
  • B05C5/007—Slide-hopper coaters, i.e. apparatus in which the liquid or other fluent material flows freely on an inclined surface before contacting the work
  • B05C5/008—Slide-hopper curtain coaters
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/46—Pouring or allowing the fluid to flow in a continuous stream on to the surface, the entire stream being carried away by the paper
  • D21H23/48—Curtain coaters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C9/00—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important
  • B05C9/06—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important for applying two different liquids or other fluent materials, or the same liquid or other fluent material twice, to the same side of the work

Definitions

• the present invention relates to a coating apparatus for paper/board web, the apparatus comprising at least one nozzle unit having a feeding chamber extending in the longitudinal direction of the coating apparatus, into which chamber a coating is conveyed by feeding means, and a nozzle slot in flow communication with the feeding chamber, the said slot also extending in the longitudinal direction of the coating apparatus, and to which the coating is supplied from the feeding chamber over the total width of the nozzle slot and further conveyed out of the outlet opening of the nozzle slot.
• the coating apparatus may be a slide-fed curtain coater or a jet coater.
• curtain coaters are becoming more widely used for coating paper or board webs, because they exert much less force on the web than blade coating/rod coating, and thus cause fewer interruptions due to the breaking of the web being coated, thus improving runnability.
• curtain coating the same smoothness is not achieved as with blade coating, but the coverage attained is better than that attained with blade coating.
• curtain coaters can be divided into slot-fed and slide-fed coaters.
• the coating is supplied by means of a nozzle unit onto an inclined plane, along which the coating flows towards the edge of the plane, whereby a curtain is formed as the coating drips from the edge of the plane.
• the coating is pumped via a manifold into a narrow vertical slot on the lip of which the curtain is formed and drips onto the web.
• the coating may be spread in one or more layers.
• the curtain thus formed is guided by means of an edge guide, which is located on the edge of the feeding slot/feeding lip, as indicated by its name.
• An edge guide which is located on the edge of the feeding slot/feeding lip, as indicated by its name.
• a considerable problem with current coating paste coaters is presented by the drying of the paste and the formation of clogging in the chambers of the nozzle unit and in the nozzle slot. Even the slightest clogging can cause significant production losses.
• a normal nozzle unit consists of several profile sheets of approximately rectangular outline, which are connected to each other by means of track bolts. This type of structure does not make possible easy and rapid opening of the nozzle units for cleaning purposes.
• one important aim of the present invention is to provide an improvement in a coating apparatus for spreading coating paste on a paper/board web, such as a curtain coater or jet coater, which improvement will allow the nozzle unit to be easily and rapidly opened, thus making possible easy and reliable washing of the chambers and nozzle slot of the nozzle unit.
• the coating apparatus is characterised in that the coating apparatus comprises means for the rapid opening of the said at least one nozzle unit to clean the nozzle unit of dried or clogged coating.
• Figure 1 shows a perspective view of a slide-fed curtain coater according to the invention when the nozzle unit is in a closed state
• Figure 2 shows the curtain coater of Figure 1 when the nozzle unit is in an open state
• FIG 3 shows the situation in Figure 2 as seen from the feeding end
• Figure 4 shows the situation in Figure 1 as seen from the feeding end
• Figure 5 shows a curtain coater as seen diagonally from below in the open state of the nozzle unit.
• the slide-fed curtain coater 1 according to the invention shown in Figures 1 to 5 comprises nozzle parts 3, 3a and 32 located on bearers 2 forming a supporting structure, the said nozzle parts together forming a nozzle unit, which has three nozzle slots 31 that make multiple coating possible.
• the outermost nozzle part 3a is fixed solidly on the bearers 2 and its edge 33 forms a feeding lip, over which the coating paste flowing along the upper surface of the nozzle unit is conveyed to form a coating curtain and to guide it by means of edge guides (not shown) onto the surface of the paper/board web to be coated which is travelling below the coater.
• the movable nozzle parts 3 and 32 are connected onto movable opening arms 8 by means of movable pins 10.
• the curtain coater comprises a fixed support 5 resting on the bearers 2 and extending in the longitudinal direction of the nozzle unit, on the other side of the said support, between the innermost nozzle part 32 and the fixed support 5, is a closing tube 6, and on the opposite side, between the fixed support 5 and the opening arms' support 9, is an opening tube 7, whereby by pressurising the closing tube 6, the movable nozzle parts 3, 32 can be made to move towards the fixed nozzle part 3a to close the nozzle unit ( Figure 1), and by releasing the pressure from the closing tube 6 and pressurising the opening tube 7, the movable nozzle parts 3, 32 can be made to move away from the fixed nozzle part 3a to open the nozzle unit ( Figure 2), for example, to remove dried paste from the nozzle slot and/or the different chambers of the nozzle.
• the closing and opening tubes are preferably pneumatic, allowing rapid movements to be made especially at the opening
• Reference numeral 4 denotes coating feeder pipes through which the coating is supplied to the nozzle unit.
• the feeder pipes are located at one longitudinal end of the nozzle unit, but they may also be situated elsewhere in the nozzle unit, such as at the longitudinal middle point of the nozzle unit or at both longitudinal ends of the nozzle unit depending, among other things, on the design of the feeding chamber.
• the longitudinal direction of the nozzle unit is denoted by reference mark W in Figure 2.

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

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ID=8564611

Family Applications (1)

Country Status (5)

Cited By (3)

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Citations (1)

• 2002
  • 2002-09-20 FI FI20021674A patent/FI112815B/sv active
• 2003
  • 2003-08-20 WO PCT/FI2003/000613 patent/WO2004027150A1/en active Application Filing
  • 2003-08-20 DE DE10393109T patent/DE10393109T5/de not_active Withdrawn
  • 2003-08-20 AU AU2003255542A patent/AU2003255542A1/en not_active Abandoned
  • 2003-08-20 JP JP2004537171A patent/JP4223479B2/ja not_active Expired - Fee Related

Patent Citations (1)

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