Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F7/00—Other details of machines for making continuous webs of paper
  • D21F7/006—Cutting the edges of the paper-web
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D7/00—Details of apparatus for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
  • B26D7/08—Means for treating work or cutting member to facilitate cutting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
  • B26F3/00—Severing by means other than cutting; Apparatus therefor
  • B26F3/004—Severing by means other than cutting; Apparatus therefor by means of a fluid jet

Definitions

• the invention relates to a method according to the preamble of claim 1 for cutting an object with a fluid jet.
• the invention also relates to an apparatus according to the preamble of claim 5 for cutting an object with a fluid jet.
• the object to be cut is a web moving in a web-forming machine.
• a web-forming machine refers to paper, board, tissue or pulp-drying ma- chines.
• cutting the edge of the web causes a great deal of breaks.
• cutting the web is performed with fluid jets so that narrow edge areas are cut away from both edges of the web, whereby a part different of its quality compared with the other web can be removed by the cutting.
• the cut- ting is usually performed above the web, by trim squirts arranged on both edge areas of the web.
• the trim squirts have nozzles from which a narrow fluid jet di- rected towards the web is discharged.
• the cutting is usually performed in the wire section for a web, which has become a cohesive fibre grid because of dewatering.
• the web is cut by a so-called oblique draw ap- paratus so that only a narrow strip remains in the web which strip is first brought through the machine or a machine section.
• the cutting jet is controlled so that the narrow strip widens controllably to the whole width of the web.
• FI patent publication 112180 describes a method and a device for cutting the edge of a paper web.
• two cutting fluid jets which are successive in the machine direction and directed to the edge area of the web, are used.
• the edge of the paper web is cut obliquely in a first jet angle with a jet directed to the outer edge of the web.
• the second jet located later in the machine direction, the oblique edge achieved in the previous stage is cut again, which second jet is directed less obliquely in a second jet angle to the outer edge of the web.
• the purpose of the second jet is to trim the cut of the first jet.
• JP patent publication 2001287071 describes an apparatus in which an immobile object is processed with a water jet.
• the specification describes a mirror arrangement by means of which it is possible to make laser light reflect in a water jet.
• DD patent publication 29611 A describes an apparatus in which an immobile object is cut with a water jet.
• light is directed into the water jet in a nozzle of a device producing the water jet by means of mirror surfaces.
• the illuminated water jet hitting the object is photographed with a video camera and, based on this video picture, the water jet is controlled.
• the cutting jet by which a moving web is cut in the web-forming machine, is illuminated, whereby it is easier to observe possibly occurring faults in the cutting jet.
• the arrangement according to the invention can be used in connection with the cutting of the edge of the web and in connection with the oblique draw apparatus.
• Observation of the illuminated fluid jet can be done directly by a visual survey or by means of cameras.
• the camera picture can, for its part, be observed directly by a visual survey or the picture can be analysed by an automatic picture interpretation process.
• cheaper and less accurate cameras can be used in the camera monitoring compared with a situation in which the fluid jet is not illuminated.
• the cutting apparatus can be provided with a remote control apparatus, whereby trim squirts can be adjusted e.g. based on the picture given by the cameras.
• Fig. 1 shows a schematic section in the cross-machine direction of a cutting appa- ratus according to the invention.
• Fig. 2 shows a schematic section in the cross-machine direction of another cutting apparatus according to the invention.
• Fig. 3 shows a cross-section of a nozzle of a trim squirt.
• Fig. 1 shows a schematic section in the cross-machine direction of a cutting appa- ratus 20 of the edge of the web i.e. a so-called trim squirt.
• Fluid which is usually water, is fed in the direction shown by arrow S to the trim squirt from which it is led via a nozzle 21 as a jet 22 having a small diameter towards a web 12 travelling on a wire 11,
• the jet 22 of the trim squirt cuts away a strip 12a from the edge area of the web 12.
• a laser light source 30 including a lens and/or a window 31, from which a laser light beam 32 produced by the laser light source 30 is led to the water jet produced by the trim squirt so that it illuminates the jet 22 discharging from the nozzle 21 from inside.
• the cutting jet 22 is observed with a video camera 40, which is connected to a control apparatus 100.
• the control apparatus 100 it is possible to control the trim squirt 20.
• the laser light source 30 is placed outside the trim squirt 20.
• the laser light beam 32 produced by the laser light source 30 is led by an optical fibre 33 to the lens and/or window 31 in the trim squirt 20, from which the laser light beam 32 produced by the laser light source 30 is led to the water jet produced by the trim squirt 20 so that it illuminates the jet 22 discharg- ing from the nozzle 21 from inside.
• Fig. 3 shows a cross-section of a nozzle 210 of the trim squirt.
• the nozzle 210 comprises a transparent first nozzle part 211, which includes a round nozzle hole in the middle. Below the first nozzle part 211 there is a second nozzle part 212, and above the first nozzle part 211 there is a third nozzle part 213.
• the second 212 and the third 213 nozzle part include a round hole in the middle the diameter of which is larger than the round nozzle hole of the first nozzle part 211.
• the first nozzle part 211 is thus supported between the second 212 and the third 213 nozzle part.
• the third nozzle part 214 is arranged a light source 214 and a light- reflecting surface 215 related to it of a truncated cone shape which surface reflects the light produced by the light source 214 towards the first transparent nozzle part 211.
• the light penetrates the first nozzle part 211 and continues after that as a cylindrical light curtain around the jet 22 discharging from the nozzle 210.
• the light source 214 is located outside the water space of the nozzle and it can be con- stituted of one or several light sources.
• the jet 22 discharging from the nozzle of the trim squirt 20 will thus be visible as a uniform chink of light in a situation in which the jet 22 is flawless. If the jet 22 is abnormal and it becomes beaded, the light scatters in the water drops, whereby an outside observer of the jet will not see a uniform chink of light.
• the laser light source is well suited for the arrangement according to the invention, because it produces a strongly directed narrow beam of light, but also some other light source producing a directed beam of light can naturally be utilised.
• the illumination of the jet is advantageously performed by light directed in the direction of the jet, because then the whole jet can be illuminated by a small light source. If the jet is illuminated e.g. from the side, the light source has to be larger in order for the whole jet to become illuminated. A light source illuminating the jet from the side causes problems with dirtying.
• the edge-cutting apparatus is located in a place picking dirt i.e. pulp on the wire section of the machine, whereby all dirt-picking surfaces have to be minimised.
• the alignment of the jet (the angle of the jet towards the wire and the position of the jet in the machine and cross-direction) e.g. in a shutdown/start situation can be performed by laser light without a water j et.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Forests & Forestry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Laser Beam Processing (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

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Cited By (2)

Citations (4)

• 2006
  • 2006-01-31 FI FI20065066A patent/FI119503B/sv not_active IP Right Cessation
• 2007
  • 2007-01-23 WO PCT/FI2007/050035 patent/WO2007088243A1/en active Application Filing
  • 2007-01-23 DE DE112007000425T patent/DE112007000425T5/de not_active Withdrawn

Patent Citations (4)

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