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
  • D21F1/32—Washing wire-cloths or felts

Definitions

• the invention relates to a device for cleaning a conveyor belt of a web processing machine, in particular a machine for the production or further processing of paper, cardboard or tissue.
• a large number of conveyor belts are used in a paper machine to transport a fibrous web to be produced.
• the conveyor belts are used, for example, in the form of forming fabrics in the forming section, in the form of press felts in the press section and in the form of drying fabrics in the drying section or as transfer belts.
• the screens and felts are often at least partially designed as fabric bands with an open pore structure.
• the conveyor belts are increasingly contaminated by soiling, for example in the fiber suspension, such as adhesives or other additives.
• soiling for example in the fiber suspension, such as adhesives or other additives.
• the pores and meshes settle over time with the above-mentioned Fabrics too.
• EP 0 731 212 A1 discloses a cleaning device with rotatable cleaning nozzles.
• the cleaning nozzles are inclined against the transport path, the rotation of the nozzles continuously changing the direction of inclination of the nozzles between the inclination in the running direction of the transport path and the inclination against the direction of the transport path.
• the cleaning medium thrown back from the conveyor belt led away via a suction channel, which is arranged parallel to the axis of rotation of the cleaning nozzles.
• the device for cleaning a preferably moving conveyor belt of a web processing machine.
• the device has at least one cleaning nozzle through which a cleaning medium can be applied to the moving conveyor belt.
• the at least one cleaning nozzle is arranged such that the cleaning medium is always inclined in a jet shape against the running direction of the conveyor belt and meets the conveyor belt at a cleaning point at an angle of incidence ⁇ of greater than 5 ° and less than 85 °.
• the conveyor belt to be cleaned moves under the cleaning point.
• the arrangement of the cleaning nozzle inclined according to the invention such that the cleaning medium is always sprayed as a jet inclined against the running direction of the conveyor belt and hits the conveyor belt at an angle of incidence ⁇ between 5 ° and 85 °, the relative speed between the conveyor belt to be cleaned and the Cleaning medium increased. Due to the increase in speed, the impulse between the cleaning medium and contamination on the conveyor belt is increased, which considerably improves the cleaning performance. Furthermore, the jet of the cleaning medium "peels" or "scoops" the dirt off the surface of the transport path to be cleaned, in that the dirt particles are washed down and lifted off due to the oblique impact.
• angle of incidence ⁇ is preferably between 15 ° and 75 °, particularly preferably between 30 ° and 60 °.
• the at least one cleaning nozzle is stationary, in particular cannot be rotated.
• This feature considerably simplifies the design of the cleaning device according to the invention. On the one hand, this leads to a simpler structure, since there is no need for a complex movement mechanism, as a result of which the cleaning device can be produced at low cost. On the other hand, this considerably reduces the maintenance effort and the susceptibility to faults, in particular since the area in which the cleaning nozzle is arranged has a very strong tendency to become dirty.
• the cleaning medium is braked after the impact on the surface of the conveyor belt.
• a part of the cleaning medium typically 30% of the loaded cleaning medium, passes through the conveyor belt (if the structure is porous), another part remains in the conveyor belt (5%) and another part is thrown back by the conveyor belt.
• the part thrown back is at oblique angle of incidence ⁇ between 5 ° and 85 ° for the most part (more than 50%) as a fanned jet, depending on the angle of incidence ⁇ , the structure of the conveyor belt, the machine speed and the pressure of the emerging cleaning medium at an average angle y between 5 ° and 75 °, preferably reflected between 15 ° ⁇ 10 ° against the running direction of the conveyor belt.
• the reflected jet entrains air, cleaning medium mist and dissolved impurities, which creates a suction effect in the direction of the reflected jet.
• the cleaning device usually has a suction channel with a suction opening for taking away the cleaning medium thrown back from the conveyor belt and mixed with dirt, into which the thrown back cleaning medium at least partially directly enters.
• a particularly preferred embodiment of the invention provides that the suction opening extends at least in sections pointing in the direction of the cleaning point on the side opposite the cleaning nozzle in relation to the cleaning point is arranged, the central axis of the suction channel in the area of the suction opening with the conveyor belt forming an angle ⁇ between 5 ° and 75 °.
• the suction opening according to this embodiment points in the direction of the reflected beam, ie the suction opening faces the reflected beam.
• the Cleaning medium which is reflected by the cleaning point against the direction of travel of the conveyor belt, can also be suctioned off more easily, since the suction opening extends at least in sections in the half-space of the reflected cleaning medium, facing the latter. Since the average reflection angle Y at the angles of incidence ⁇ specified above is usually in the range between 5 ° and 75 °, it is possible with the arrangement of the suction opening according to the invention to couple the reflected beam into the suction channel better than in the known embodiments in which the suction opening is not facing the reflected beam.
• the cleaning performance of the cleaning device can also be increased, since more cleaning medium can be used due to the increased suction power, the conveyor belt after cleaning and suction being just as dry as in known suction channel configurations with less use of cleaning medium.
• the relative position between the suction opening and the at least one cleaning nozzle is preferably fixed.
• the angle ⁇ is preferably between 5 ° and 50 °, particularly preferably between 5 ° and 25 °.
• the central axis is in the Extends the area of the suction opening essentially in the extension of the cleaning medium reflected at the central angle y, that is, when the central axis in the area of the suction opening has the smallest possible parallel offset to the beam of the cleaning medium reflected at the central reflection angle y and when the central axis also has in the area of the suction opening the mean angle y includes the smallest possible angle.
• the parallel offset can usefully be at a maximum such that the portion of the beam reflected at the central angle y can still enter the suction opening directly.
• the central axis of the suction channel in the area of the suction opening with the mean angle y includes the angle ⁇ in the range between ⁇ 25 °, preferably between ⁇ 15 °, very particularly preferably between ⁇ 5 ° and / or
• the extension of the central axis of the suction channel in the area of the suction opening cuts the conveyor belt in the area of the cleaning point, i.e. no parallel offset between the central axis of the suction channel in the area of the suction opening and the portion of the jet of the cleaning medium reflected at the central angle y.
• a particularly preferred embodiment variant of the invention therefore provides that the cross-sectional area of the suction opening and the distance of the suction opening from the cleaning point are coordinated with one another in such a way that a cross-sectional area of the suction opening that is reflected at the mean angle y and in the opening angle range ⁇ of ⁇ 15 ° is preferred jet of cleaning medium fanned out by ⁇ 25 ° can pass through the cross-sectional area of the suction opening.
• the cleaning medium which, for example, in the form of fog not as fanned out beam is reflected in the direction of the mean reflection angle Y, it makes sense if a suction space is formed in the running direction of the conveyor belt after the suction opening, which extends at least in sections in the direction of the at least one cleaning nozzle and has an opening that runs horizontally to the conveyor belt ,
• the suction channel In order to guide the cleaning medium flowing in the suction channel as smoothly as possible in a laminar flow through the suction channel, it makes sense if the suction channel extends at least in sections straight and / or curved with a radius of curvature between 10 mm to 200 mm. Here the radius can change with the angle of the swept arc.
• the suction channel can have a constant cross-sectional area at least in sections.
• the suction channel and / or the suction opening can also be round or have a square cross-section.
• the cleaning nozzles are not arranged parallel to one another. In order to increase the cleaning performance, they can be oriented in such a way that the rays of the cleaning medium emerging from the cleaning nozzles are focused on the cleaning point.
• Cleaning nozzles with a round cross-section have proven their worth. It is therefore advantageous if at least one cleaning nozzle has a round cross section.
• Cleaning nozzles with a diameter between 0.1 mm and 0.5 mm, preferably between 0.15 mm and 0.3 mm, are advantageous with regard to availability and water consumption.
• the cleaning medium has a pressure between 20 bar and 1000 bar, preferably between 200 bar and 500 bar, when it emerges from the cleaning nozzle.
• the cleaning medium has a liquid and / or gaseous component. Water with or without additives is often used as the cleaning medium.
• the temperature of the cleaning medium is adapted to the ambient temperature. Since, depending on the location, temperatures between 20 ° C. and 120 ° C., often between 50 ° C. and 100 ° C., prevail, a preferred embodiment of the invention provides that the cleaning medium preferably has a temperature between 20 ° C. and 120 ° C. between 50 ° C and 100 ° C.
• the suction channel has a vacuum device after the suction opening in the direction of the reflected cleaning medium flowing in the suction channel.
• the vacuum device has at least one injector nozzle for injecting an injection medium.
• a negative pressure in the manner of a water jet vacuum is generated by the suction effect of the air layers accelerated with the injection medium, so that dirt particles, mist and drops of cleaning medium are entrained in the direction of the outlet opening.
• Another advantage of injecting the injection medium is that the suction channel is permanently flushed, which can reduce or prevent dirt deposits in the suction channel.
• the cross section of the suction channel in the region of the at least one injector nozzle must widen in the direction of the cleaning medium flowing in the suction channel in order to avoid backflow.
• the at least one injector nozzle is therefore advantageously arranged in such a way that the injection medium is injected at least in sections parallel to the central axis of the discharge channel.
• the injection medium which emerges from the injector nozzle which is arranged in the direction of flow, has a pressure between 20bar and 1000bar, preferably between 200bar and 500bar, and when the injector medium. , which emerges from the injector nozzle behind it in the direction of flow, has a pressure between 20bar and 40bar at the outlet.
• At least one injector nozzle has a round or oval or rectangular cross section and its diameter is in the range between 0.1 mm and 0.5 mm, preferably between 0.15 mm and 0.3 mm.
• the injector nozzle behind it preferably has a 1 mm and 2 mm, preferably 1.5 mm.
• the injector medium can have a liquid and / or gaseous component.
• the injector medium is warmed or cooled with respect to the ambient temperature. Heating prevents condensation in the suction channel. Furthermore, rinsing can be carried out more effectively.
• the injector medium has a temperature between 30 ° C and 100 ° C, preferably between 30 ° C and 70 ° C.
• the injector medium has a temperature between 4 ° C and 50 ° C, preferably between 8 ° C and 25 ° C.
• At least one air knife is arranged in the running direction of the conveyor belt after the at least one cleaning nozzle, by means of which compressed air can be applied to the conveyor belt, which strikes the conveyor belt at an angle ⁇ between 10 ° and 80 °, preferably between 50 ° and 70 ° in the running direction ,
• the air knife can be used to blow off and / or atomize residues of the cleaning medium that are on the surface or in the conveyor belt.
• entry of false air into the area of the cleaning nozzles can be prevented.
• the air knife at least in sections forms a plurality of individual jets which are arranged next to one another transversely to the running direction of the conveyor belt and / or that the air knife at least in sections forms a slit-like air curtain extending transversely to the running direction of the conveyor belt.
• the air knife fulfills its tasks particularly well when the compressed air has a pressure between 1 bar and 10 bar, preferably between 4 bar and 7 bar.
• the compressed air is advantageously heated to a temperature between 20 ° C. and 200 ° C., preferably between 50 ° C. and 200 ° C. If the compressed air heated above ambient temperature is blown onto / into the conveyor belt, the conveyor belt is actively dried.
• the invention is explained below using an advantageous exemplary embodiment and the following drawings. Show it:
• FIG. 1 shows a device according to the invention for cleaning a conveyor belt in longitudinal section
• FIG. 2 shows a cleaning head according to the invention in a frontal view
• Figure 3 shows the cleaning device according to the invention in an arrangement for the paper machine.
• FIG. 1 shows a cleaning device 1 according to the invention for cleaning a conveyor belt 2 of a web processing machine.
• the cleaning device 1 has a plurality of cleaning nozzles 3 arranged in a cleaning head 18, of which only one can be seen in the present illustration.
• a cleaning medium 4 can be applied to the conveyor belt 2 at the cleaning point 5 by the cleaning nozzles 3.
• the cleaning nozzles 3 are arranged in such a way that the cleaning medium 4, as a jet 7, is always inclined against the running direction 6 of the conveyor belt 2 at an angle of incidence ⁇ between 5 ° and 85 ° at the cleaning point 5 at the conveyor belt 2.
• the incident beam 7 includes an angle of incidence ⁇ of 45 ° with the transport path 2. Tests have shown that generally very satisfactory cleaning results are achieved if the angle of incidence ⁇ is preferably between 15 ° and 75 °, particularly preferably between 30 ° and 50 °.
• the cleaning nozzles 3 are fixed in relation to the conveyor belt 2, in particular they cannot be rotated.
• the device 1 for cleaning the conveyor belt 2 has a suction channel 8 with a suction opening 9.
• the suction channel 8 has a central axis 10. Through the suction opening 9, cleaning medium 4 mixed with dirt enters the suction channel 8 after it is thrown back by the conveyor belt 2. A large part of the cleaning medium 4 thrown back by the conveyor belt is reflected as a fanned beam 11 at an average angle Y by the conveyor belt 2 against the running direction 6 of the conveyor belt 2.
• the suction opening 9 extends on the side which is arranged opposite the cleaning nozzles 3 in relation to the cleaning point 5.
• the suction opening 9 points in the direction of the cleaning point 5 and thus in the direction of the reflected beam 11.
• the central axis 10 of the suction channel 8 in the area of the suction opening 9 includes an angle ⁇ between 5 ° and 75 ° with the conveyor belt 2.
• the cross-sectional area 27 of the suction opening 9 and the distance A between the cross-sectional area 27 and the cleaning point 5 are coordinated with one another such that a cross-section area 27 of the suction opening 9 reflects and im Opening angle range ⁇ ⁇ 25 ° fanned beam of the cleaning medium can pass through the cross-sectional area 27 of the suction opening 9.
• a suction chamber 12 is formed in the running direction 6 of the conveyor belt 2 after the suction opening 9.
• the suction space 12 extends in the direction of the cleaning nozzles 3 and surrounds them.
• the suction chamber 12 has an opening 13 which runs horizontally to the conveyor belt 2 and is spaced from the conveyor belt 2 between 1 mm and 10 mm, preferably between 3 mm and 5 mm.
• the suction channel 8 is first curved in the direction of flow of the reflected beam 11 with a radius of curvature 100 mm and then extends straight, whereby the suction channel 8 takes the form of a "shoe".
• the suction channel 8 after the suction opening 9 has a vacuum device in the form of one or more injector nozzles 16 for injecting an injection medium 17.
• a section 14 of the suction channel 8, which extends between the suction opening 9 and the injector nozzle 16, has a constant cross-sectional area.
• the section 15 of the suction channel 8 adjoining the section 14 extends straight.
• the cross section of the suction channel in the area 15 widens starting from the injector nozzle 16 in the direction of the cleaning medium 4 flowing in the suction channel 8.
• the injector nozzle 16 is arranged in such a way that the injection medium 17 is injected at least in sections parallel to the central axis 10 of the discharge channel 8 in the area 15.
• the suction channel and / or the suction opening can have a round or square cross section. - 1 ⁇
• the injection medium 17 has a pressure between 20 bar and 100 bar, preferably between 200 bar and ⁇ OO bar, when it emerges from the injector nozzle. Furthermore, the injector nozzle 16 can have a round or oval or rectangular cross section. The injector nozzle 16 preferably has a diameter ⁇ between 0.1 mm and O. ⁇ mm, preferably between 0.1 ⁇ mm and 0.3 mm. The injector medium can have a liquid and / or gaseous component and is water in the present exemplary embodiment. In order to increase the suction effect and thus the suction power due to local pressure reduction in the suction channel 8, in the present exemplary embodiment the injector medium 17 has cooled with respect to the ambient temperature and has a temperature of 8 ° C.
• an air knife 19 is arranged, through which the conveyor belt 2 can be pressurized with compressed air 20, which is at an angle ⁇ between 10 ° and 80 °, preferably between 60 ° and 70 ° in the running direction 6 Conveyor belt 2 hits.
• the air knife 19 can be formed at least in sections by a plurality of individual jets which are arranged next to one another transversely to the running direction 6 of the conveyor belt 2 and / or at least in sections by a slit-like air curtain extending transversely to the running direction 6 of the conveyor belt 2.
• the compressed air has a pressure of ⁇ bar.
• FIG. 2a (section line aa in FIG. 1) shows the cleaning head 18 in a front view with a view of the cleaning nozzles 3, 3 ' , 3 " and 3 '" .
• the cleaning nozzles 3, 3 ' , 3 " and 3'" are arranged side by side, the cleaning head 18 being aligned such that the ⁇ cleaning nozzles 3, 3 ' , 3 " and 3 '" extend side by side transversely to the direction of travel 6 of the conveyor belt 2.
• the cleaning nozzles 3, 3 ', 3 "and 3'” have a round cross section with a diameter of 0.2 mm.
• the cleaning medium 4 emerging from the ⁇ cleaning nozzles has a pressure of 30 bar when it emerges from the cleaning nozzles 3, 3 ' , 3 " and 3 '” .
• Water is used as the cleaning medium 4. To prevent condensation of the cleaning medium, it is heated to 100 ° C above room temperature.
• FIG. 3 shows a view of the cleaning device 1 in combination with a machine for paper production 2 ⁇ .
• the cleaning device 1 is connected to a movement unit 21, which makes it possible to move the cleaning device transversely (CD) to the running direction 6 of the transport path 2.
• An outflow line 23 is arranged in the flow direction of the cleaning medium 4 carried away after the movement unit 21, through which the cleaning medium is guided further away.
• Flow accelerators 22 in the form of injector nozzles 22 are arranged in the discharge line 23.
• the injector nozzles 22 have a nozzle diameter between 1mm and 2mm, preferably 1, ⁇ mm.
• the pressure of the injector medium as it emerges from the injector nozzles 22 is in the range from 20 bar to 40 bar.
• the system thus has a plurality of injector nozzles 16 and 22 arranged one behind the other in the flow direction of the cleaning medium 4 to be removed.
• the injector medium 26 injected by the injector nozzles 22 is subjected to a lower pressure than the injector medium 17.

Landscapes

• Cleaning In General (AREA)
• Cleaning Or Drying Semiconductors (AREA)
• Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
• Glass Compositions (AREA)
• Treatment Of Fiber Materials (AREA)

Applications Claiming Priority (2)

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• 2004
  • 2004-05-19 DE DE102004025291A patent/DE102004025291A1/de not_active Withdrawn
• 2005
  • 2005-04-28 EP EP05740038A patent/EP1753909B1/fr not_active Expired - Lifetime
  • 2005-04-28 WO PCT/EP2005/051927 patent/WO2005113890A1/fr not_active Ceased
  • 2005-04-28 DE DE502005008413T patent/DE502005008413D1/de not_active Expired - Lifetime
  • 2005-04-28 AT AT05740038T patent/ATE447070T1/de active

Non-Patent Citations (1)

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