Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G3/00—Doctors
  • D21G3/005—Doctor knifes
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G3/00—Doctors
• • 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
  • D21H23/32—Addition to the formed paper by contacting paper with an excess of material, e.g. from a reservoir or in a manner necessitating removal of applied excess material from the paper
  • D21H23/34—Knife or blade type coaters

Definitions

• the invention relates to an apparatus for a web forming machine the apparatus being doctor equipment adapted at both of its ends to the web forming machine with support means and the doctor equipment including a composite blade holder to which the support means are connected.
• An apparatus is, for example, doctor equipment with a simple construction which is loaded against the surface to be doctored by gravity. As manufactured by the applicant, such doctor equipment is marketed under the product name FiberDoc Lite.
• the blade holder included in the doctor equipment has a composite construction with overhanging shafts adapted to both of its ends. Bearing assemblies adapted to the overhanging shafts are attached to a web forming machine. Finally, a weight is attached to the overhanging shaft to provide loading by gravity.
• the proposed doctor equipment is suitable only to relatively narrow web forming machines. Furthermore, despite the weight, the generated blade pressure may turn out to be insufficient. On the other hand, even the smallest weights require a large installation space and collect loose matter on top of them. Consequently, the load of the doctor equipment changes during use. Basically, the load can also be increased, but it requires modifications- in the construction or at least in the components of the doctor equipment. Due to gravity loading, the doctor equipment must also be set in a certain position, which restricts the application of the doctor equipment.
• Doctor apparatuses also exist in which the blade holder is supported to a specific doctor beam.
• the doctor beam is supported turnably by its ends to a web forming machine.
• pneumatic cylinders are used, which are adapted between the web forming machine and the doctor beam.
• pneumatic cylinders With pneumatic cylinders, a sufficient blade pressure is most often achieved and loading can even be adjusted. In addition, the doctor beam can be turned to the maintenance position.
• pneumatic cylinders require a large installation space.
• the movements of pneumatic cylinders are often too fast and sudden.
• the doctor beam tends to turn slowly.
• the static friction of a stuck pneumatic cylinder is remarkable. As the static friction changes back to the kinetic friction, the piston of the pneu- matic cylinder jerks forward, which produces disadvantageous load peaks to the doctor equipment and the surface to be doctored.
• the object of the invention is to provide a novel apparatus for a web forming machine being more versatile than heretofore, yet simpler, and avoiding the prior art problems.
• the characteristic features of this invention are that the actuator of the apparatus includes one pneumatic muscle.
• the actuator becomes small-sized.
• great forces are achieved with the actuator.
• the pneumatic muscle is reliable and withstands in demanding conditions, too.
• the pneumatic muscle has high sensitivity, which is significant particularly in small movements.
• the muscle lacks the so called slip-stick phenome- non, also called stick-slip phenomenon.
• the actuator can be applied in connection with different apparatuses of a web forming machine. For example, even simple doctor equipment can be easily made loadable.
• Figure 1 shows a first embodiment of the doctor equipment according to the invention seen diagonally from behind
• Figure 2 shows a second embodiment of the doctor equipment according to the invention seen diagonally from be- hind
• Figure 3 shows a third embodiment of the doctor equipment according to the invention seen from the side
• Figure 4 shows a fourth embodiment of the doctor equipment according to the invention with various components disassembled
• Figure 5 shows one example of an apparatus according to the invention for a web forming machine
• Figure 6a shows doctor equipment according to the invention
• Figure 6b shows the back side end of the doctor of Figure 6a
• Figure 6c shows the front side end of the doctor of Figure 6a
• Figure 7 is a cross-sectional view of an actuator according to the invention.
• Figures 1 - 4 illustrate various doctor apparatuses according to the invention for a web forming machine.
• Web forming machines include paper and board machines as well as other corresponding machines.
• Doctor equipment is usually adapted at both of its ends to the web forming machine with support means (not shown) . Supporting is often accomplished with bearing assem- blies which are fastened to the frame of the web forming machine.
• An essential part of doctor equipment is also a blade holder which is used, as the name implies, to hold and support a doctor blade or other corresponding blade in the doctor equipment.
• a doctor blade is used, for example, to detach a paper web from a roll surface or to otherwise keep clean the surface of a roll or other moving element by doctoring. Doctor blades are used in coating apparatuses as well.
• the apparatus includes an actuator 12 including at least one pneumatic muscle 13.
• the pneumatic muscle 13 is adapted in relation to either of the two ends of the doctor equipment and the actuator 12 is adapted to load and open the doctor equipment.
• the actuator 12 thus includes at least one pneumatic muscle 13.
• the actuator 12 is arranged between support means 10 and a blade holder 11. Due to the actuator, the blade holder can now be loaded and loading can additionally be adjusted. Opening the doctor equipment is also possible now. 'Opening' refers to turning the blade holder from the operating position to the maintenance position for the duration of cleaning and blade replacement, for example.
• one pneumatic muscle 13 is used, which is basical.ly a single-acting cylinder.
• the pneumatic muscle lacks a conventional piston and piston rod. In this case the kinetic friction is missing almost entirely, the operation of the muscle being thereby smooth without harmful sticking or jerking.
• a roll 14 and doctor equipment adapted in relation thereto are shown only partially.
• the surface of the roll 14 is doctored with a doctor blade 15, which is adapted to a composite blade holder 11.
• a mount- ing casing 17 included in the actuator 12 is integrated as a part of the support means 10.
• the construction is very compact and can be easily fastened to the blade holder.
• the support means 10 are provided with a mounting flange 18 with holes 19 by means of which the doctor equipment is fastened to a web forming machine.
• the mounting 5 casing is unmovably connected to either the blade holder or the support means.
• the mounting casing 17 is thus unmovably fastened to the support means 10.
• the fastening of the pneumatic muscle can also vary.
• the first end 20 of the pneumatic muscle 13 is fastened to the mounting casing
• the actuator can also be so adapted that upon releasing the pressure the doctor blade detaches from the surface to be doctored. Due to the round drive circle equipped with fastening holes located at regular intervals, the blade holder can be positioned freely relative to the support means. Support means
• Support means equipped with an actuator can also be retrofitted to existing doctor apparatuses .
• Figure 2 shows a second embodiment of the doctor equipment according to the invention.
• a composite blade holder 11- known as such is applied.
• the actuator 12 and the mounting casing 17 surrounding it are placed between the blade holder 11 and a bearing 23 included in the support means 10.
• the actuator includes a second pneumatic muscle 24.
• the first ends of both muscles 13 and 24 are fastened to a mounting casing 17.
• the second ends are fastened to a drive circle 22, on different sides of an overhanging shaft 16.
• the lower pneumatic muscle 13 is mainly for loading.
• the upper pneumatic muscle 24 is for opening the doctor equipment and it can also be used to generate a counter-pressure for the muscle to be loaded.
• the muscles are here similar to each other. On the other hand, the muscles can be different for their characteristics, if required.
• Figure 3 is a basic view of a third embodiment of the doctor equipment according to the invention. As to its basic design and operation, this resembles the embodiment of Figure 2.
• a pneumatic muscle 13 adapted to a mounting casing 17 is used to load the doctor equipment.
• the pneumatic muscle 13 is pressurized and it is therefore slightly inflated.
• the actuator includes a spring element 25.
• the use of a spring element simplifies the construction of the actuator and by substituting the spring element, the characteristics of the actuator can be adjusted in a simple way.
• the spring element 25 and the second pneumatic muscle 24 are fastened in a corresponding way as the first pneumatic muscle 13.
• An overhanging shaft 16 extends through a drive circle 22 and a mounting casing 17.
• the drive circle 22 is additionally tied to a blade holder 11 with clips 26, whereby the force generated by the actuator 12 is conveyed from the drive circle to the blade holder 11.
• a presser blade 27 is additionally used in connection with the doctor blade 15.
• FIG. 4 A fourth embodiment of the doctor equipment according to the invention is shown in Figure 4.
• a support construction 28 which extends over the entire length of the doctor equipment.
• a small-sized blade holder can be used as a beam-like support construction supports the main part of the doctor equipment load.
• An actuator 12 according to the invention is adapted between the end component 30 of the support construction 28 and support means 10, at the right-hand side end of the support construction 28.
• two mutually symmetrical profile components 31 are meant to be connected to each other by gluing.
• the support construction 28 also includes end components 30 adapted to both ends.
• the shape of the end component corresponds substantially to the support construction 28 formed from the profile components 31 and it extends at least partially into the support construction 28. Firstly, the end component 30 closes the open construction and, on the other hand, the portion extending inside solidifies the end of the support construction 28. Functionally similar parts are referred to using identical reference numbers.
• the unloaded length of the pneumatic muscle 13, 24 is 50 - 500 mm, more advantageously 100 - 300 mm.
• the actuator becomes advantageously small-sized.
• the length of the achievable axial movement is 1 - 50 mm.
• the unloaded diameter of the pneumatic muscle 13, 24 is 10 - 50, more advantageously 20 - 40 mm. Regardless of its small size, a slow and accurate movement is achieved with the pneumatic muscle. At the same time, forces are generated which are more than ten-fold compared to a conventional pneumatic cylinder of a corresponding size.
• PAMs 11.09.2007
• the basic principle is to cover a flexible hose with a rhombic fabric made of rigid fibers whereby a three-dimensional network pattern is formed.
• the hose expands and the shape of the network pattern changes. In this way an axial force is generated and the muscle shortens at the same time.
• the network pattern Upon releasing the pressure, the network pattern returns to its original shape and the muscle lengthens to its previous dimension.
• the muscle is also very lightweight and completely hermetically sealed.
• the muscle is at the same time efficient and fast, but slow movements are also possible, on the other hand.
• the muscle is accurately controllable and, in addition, sticking and sliding can have been eliminated. That is, the stick-slip phenomenon can be avoided. (http: //en.
• a pneumatic muscle can be applied in a web forming machine in other positions as well.
• a muscle-based actuator can be used, for example, for shaking a fabric or oscillating a doctor.
• a muscle can also be used for implementing various precision adjustments of the headbox.
• the force of the muscle can be conveyed around a corner.
• Figure 5 shows one apparatus according to the invention for a web forming machine.
• This apparatus is a fabric shaker in which an actuator 12 is used to operate a control element 34.
• the control element 34 is used to change the phase difference of eccentric masses 35 to provide a vibrating movement.
• This fabric shaker is described in more detail in the European patent No. 1694910 of the applicant. Deviating from Figure 5, a small muscle can even be installed inside a control element or another construction.
• Figure 6a shows a fifth embodiment of the doctor equipment according to the invention.
• the doctor equipment is adapted at both of its ends to a web forming machine with support means 10.
• the doctor equipment includes a composite blade holder 11 to which the support means 10 are connected.
• the composite blade holder forms the construction supporting the doctor blade 15.
• a separate doctor beam is not necessary.
• the term 'composite' is used to refer to a construction made of a fi- ber-reinforced polymeric material.
• the blade holder is manufactured as continuous and thus seamless by means of pultrusion.
• At the end of a suitably dimensioned blade holder only simple bearings 23 are installed which are fastened to the web forming machine with support means 10.
• the support constructions 10 are composed of simple plate constructions whereby the doctor equipment can be set in a correct location and position relative to the roll 14.
• the roll is a fabric return roll.
• a collection chute 36 with which the material detaching from the surface of the roll 14 during doctoring can be controllably recovered.
• a discharge connection 37 is addition- ally disposed at the back side end of the collection chute 36. In this case the material can be taken out of the doctor equip- ment by washing with the cleaning water, for example.
• a construction according to the invention can easily provide an opening angle ⁇ of 10 - 25°, more advantageously 15 - 20°, for the blade holder 11.
• the opening angle ⁇ is illustrated for example in Figure 3.

Landscapes

• Coating Apparatus (AREA)
• Paper (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
• Details Of Cutting Devices (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38572966

Family Applications (1)

Country Status (5)

Citations (8)

Family Cites Families (2)

• 2007
  • 2007-09-11 FI FI20075632A patent/FI120461B/fi not_active IP Right Cessation
• 2008
  • 2008-09-10 CN CN2008801066278A patent/CN101802301B/zh not_active Expired - Fee Related
  • 2008-09-10 EP EP08805424.2A patent/EP2188447B1/en not_active Not-in-force
  • 2008-09-10 WO PCT/FI2008/050501 patent/WO2009034228A1/en active Application Filing
  • 2008-09-10 ES ES08805424.2T patent/ES2511820T3/es active Active

Patent Citations (8)

Non-Patent Citations (2)

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