Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B15/00—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form
  • F26B15/10—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions
  • F26B15/12—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions the lines being all horizontal or slightly inclined
  • F26B15/18—Machines or apparatus for drying objects with progressive movement; Machines or apparatus with progressive movement for drying batches of material in compact form with movement in a path composed of one or more straight lines, e.g. compound, the movement being in alternate horizontal and vertical directions the lines being all horizontal or slightly inclined the objects or batches of materials being carried by endless belts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
  • F26B25/001—Handling, e.g. loading or unloading arrangements
  • F26B25/003—Handling, e.g. loading or unloading arrangements for articles
  • F26B25/004—Handling, e.g. loading or unloading arrangements for articles in the shape of discrete sheets
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B2210/00—Drying processes and machines for solid objects characterised by the specific requirements of the drying good
  • F26B2210/14—Veneer, i.e. wood in thin sheets

Definitions

• the invention relates to a method for drying veneers, in particular sliced veneer, according to the preamble of claim 1 and a drying device for carrying out the method according to the preamble of claim 4.
• a feed device and a discharge device, each with a suction box are known from DE 25 23 482 A1. Furthermore, the applicant is known to install a combination of suction box and transport system with belts in a feed device and a transport system with belts in a discharge device.
• a dryer is understood to be a so-called ironing dryer.
• two conveyor belts - a carrier belt and a cover belt - which lie parallel and directly above one another and between which the veneers are transported through the dryer, at least on a not inconsiderable part of the transport route with multiple deflections so that the veneers alternately move upwards and be bent down.
• the redirection can be achieved in different ways. Or pressure is exerted on the upper conveyor belt with rollers.
• EP 0 152 576 B2 describes a dryer of the generic type, in which the belt is guided in a loop around a roller with a relatively large diameter after a straight section, a short piece being guided in a straight line between two adjacent rollers.
• EP 0 290 056 A2 describes a generic dryer with a sinusoidal belt guide, which is achieved by many rollers with a small diameter. Additional rod-shaped rollers can be attached in addition to the rollers.
• DE 41 09 298 C2 describes a line layout of the conveyor belts corresponding to a flat omega, in which, in the case of at least one plurality of rollers, the second and fourth rollers in the direction of the dryer inlet are removed from the first and third, the second and third Rolls lie in a plane above the plane of the first and fourth rolls and the distance between the two planes is smaller than the diameter of a roll.
• DE 42 17 493 A1 describes a zigzag-like tape guide, which is achieved by staggered deflecting rollers.
• the conveyor belts are guided in the cooler in a similar way to that in the dryer.
• the aim of the iron drier is to smooth the veneers by drying during drying and cooling. Compared to dryers and coolers with a straight belt guide without pressure effect, a considerably better smoothing is achieved with most types of wood. But with sensitive types of wood such as Beech, walnut and cherry tree can create folds and cracks that make the veneer at least partially unusable.
• the committee here is 10 to 20%.
• the inventors have set themselves the task of developing a method for drying veneers, even for difficult-to-dry types of wood, in which perfectly smooth veneers are obtained and in which rejects are minimized due to folds and cracks.
• Another object is to provide a drying device for carrying out a method according to the invention.
• the first object is solved by the characterizing features of claim 1.
• Claim 4 solves the second problem.
• Claims 2 and 3 facilitate the manual work of the operating personnel.
• the sub-claims 5 to 10 contain preferred embodiments of a drying device according to the invention. The features ensure safe operation of the drying device.
• the inclined position that is the angle between the grain of the veneers and a line perpendicular to the direction of transport, is brought about with the intended angle of 20 ° to 60 °, preferably 30 ° to 50 °, when the veneers are placed on the dryer.
• the speeds of the veneers in the transport direction on the right and left are set so differently that the transfer of the veneers to the carrier belt, that is the lower conveyor belt of the dryer, takes place in the correct inclined position.
• the veneers are fixed in this position during drying and cooling because they are held mechanically between the conveyor belts.
• the discharge device largely reverses the inclined position by different speeds, which correspond to those in the feed device, in order to facilitate further handling. The operating personnel therefore do not have to get used to changed processes or handling.
• a preferred embodiment is the use of different diameters of the driven pulleys according to claim 6.
• a braking device according to claim 8 can be easily retrofitted in existing systems.
• Claims 9 and 10 show preferred embodiments of the braking device.
• Figure 1 shows a longitudinal section of a drying device according to the invention.
• Figure 2 shows the side view of a feed device according to claim 6 as a detail.
• FIG. 2a shows a detail from FIG. 2.
• FIG. 3 shows the lower belt system according to FIG. 2, viewed vertically from above.
• FIG. 4 shows the upper belt system according to FIG. 2, viewed vertically from below.
• Figure 5 shows the side view of a feed device according to claim 7 as a detail.
• FIG. 6 shows the lower belt system according to FIG. 5, viewed vertically from above.
• Figure 7 shows a braking device according to claim 9.
• Figure 8 shows a braking device according to claim 10.
• Figure 9 shows the side view of a discharge device according to claim 6 as a detail.
• a drying device consists of a feed device 1, a dryer 2, a cooler 3 and a discharge device 4.
• Each of the individual devices of the drying device has its own transport system. The speed of the individual transport systems is coordinated and depends on the drying process.
• the feed device 1 shown as a detail in FIGS. 2 to 4 is equipped for the semi-automatic feeding of the moist veneers.
• a suction box 6 and a transport system with belts 10, 16, 19, 24 arranged in parallel are fastened on a frame 5.
• the belts 10, 16, 19, 24 are arranged side by side and each run over two spaced pulleys or over a pulley and a spaced deflection.
• the pulleys are each attached to shafts.
• the arrow 32 indicates the direction of transport.
• the suction box 6 consists of a rectangular sheet metal construction with perforated sheet 7 on the underside and with at least one suction pipe 8 with a fan 9 which is arranged on the suction box.
• the suction box 6 extends over the entire width of the transport plane and is horizontal in its longitudinal direction, while it is slightly inclined in the transport direction.
• the transport system of the feed device 1 consists of an upper and a lower belt system.
• the upper belt system is divided into two.
• the endless belts 10 In the area of the suction box 6, the endless belts 10 have a flat, rectangular cross section. You are ⁇ interside the suction box along the perforated plate 7 to the pulleys 11 on the drivable shaft 12, which is mounted parallel to and spaced from the rear lower longitudinal edge of the suction box 6, and back through the suction box 6 and around the deflection 13 in front of the front lower longitudinal edge of the suction box 6 led to the perforated plate 7.
• the shaft 12 and the deflection 13 are parallel stands stored. All pulleys 11 have the same diameter.
• the second area of the upper belt system begins at the drivable shaft 14, which is mounted parallel to the shaft 12 between the suction box 6 and the shaft 12, and leads to the carrying belt 15 of the dryer 2.
• the endless belts 16, for example with a round cross section, are here from the Pulleys 17 on the shaft 14 via a cantilever of the frame 5 to the deflection 18, which is parallel to the shaft 14, and back to the pulleys 17.
• the cantilever arm can be pivoted vertically about the shaft 14, so that the height of the deflection 18 can be adjusted.
• the pulleys 17 have different diameters in such a way that there is a linear speed distribution from left to right when viewed in the direction of transport. Deviating from the horizontal, the shaft 14 is mounted at an angle such that the lower edges of the belts 16 mounted on the pulleys 17 are aligned with the perforated plate 7.
• the pulleys 17 and the deflection 18 have, for example, semicircular cutouts on their peripheral surfaces, in which the belts 16 are guided.
• the lower belt system is located below the upper belt system.
• the lower belt system is divided into two.
• the endless belts 19 with a flat, rectangular cross section are guided over the pulleys 20 on the shaft 21 and the pulleys 22 on the drivable shaft 23.
• the pulleys 20, 22 assigned to a shaft 21, 23 each have the same diameter.
• the endless belts 24 have e.g.
• the pulleys 25 have different diameters and, like the deflection 27, have cutouts on their peripheral surfaces which correspond approximately to the cross section of the belts 24 and in which the belts 24 are guided. Deviating from the horizontal, the shaft 26 is mounted at an angle such that the upper edges of the belts 24 guided on the pulleys 25 are aligned with the transport surface.
• the pulleys 11, 17, 20, 22, 25 are each firmly connected to the associated shaft 12, 14, 21, 23, 26.
• the diameters of the differently sized pulleys 17, 25 are coordinated with one another in such a way that the speed of the belts 16, 24 decreases continuously from left to right or vice versa, as seen in the direction of transport, and thus also the transport speed of the veneers 31.
• the belts 10, 16, 19, 24 can be driven via a drive system with, for example, a gear motor 29 and chain drive 30.
• the operating personnel lifts a veneer 31 in such a way that at least a part gets into the suction area of the suction box 6 and is then pressed completely against the perforated plate 7 and the belt 10.
• the belts 10 of the feed device 1 convey the veneer 31 along the perforated plate 7 in the direction of the dryer 2.
• the veneer 31 falls onto the lower belt system and is transported at an average transport speed which is that in the dryer 2 corresponds to further transported to the carrier belt 15.
• the veneer 31 is brought into a desired inclined position due to the difference in speed of the belts 16, 24.
• the required speed difference can easily be calculated from the transport distance between the shaft 26 and the deflection 27 and the angle of the inclined position.
• FIG. 5 Another embodiment of the invention according to claim 6 is shown in Figures 5 and 6.
• the structure corresponds to the previous description with the difference that the different speeds of the belts 16, 24, which can also be flat belts here, are achieved by individual drives 34, 36:
• the shaft 12 can be driven together with the shaft 23 of the lower belt system.
• the pulleys 33 which are all of the same size, are individually supported between the shaft 12 and the suction box 6.
• the axis of rotation of the pulleys 33 is parallel to the shaft 12.
• Each pulley 33 has its own controllable drive 34.
• the pulleys 35 are of the same size, are individually supported and each have an adjustable drive 36.
• the speeds of the drives 34, 36 are adjusted so that the speed of the belts 16, 24 decreases linearly from left to right or vice versa and the desired inclined position of the veneer 31 is achieved, the transport speed dependent on the process being maintained on average.
• the invention also includes all other arrangements and drive options that allow different belt speeds.
• FIG. 7 Another embodiment of the invention according to claim 9 is shown in Figure 7.
• the structure corresponds to that of Figures 2 to 4 with the differences that the belt pulleys 17, 25 have the same diameter and that a braking device is installed.
• a braking device is arranged off-center in approximately 2/3 of the width of the feed device 1 below or above the transport plane between two adjacent belts 16, 24.
• the braking device consists of a nozzle 37 with an internal suction fan 38 and an opening 39 directed towards the transport plane.
• the opening 39 is located in the immediate vicinity of the transport plane.
• a flap 40 is arranged between the suction fan 38 and the opening 39.
• the suction fan 38 In operation, the suction fan 38 generates a negative pressure in the nozzle 37.
• the flap 40 is closed. The moment a veneer 31 passes through the nozzle 37, the flap 40 opens. As a result of the pressure drop, the veneer 31 is pressed against the opening 39 and held on one side while the other side of the veneer 31 is transported further. After a certain time interval, which depends on the transport speed and the inclined position to be achieved, the flap 40 closes and the nozzle 37 releases the veneer 31, which has now reached the position at the desired angle. The further transport to the carrier belt 15 of the dryer 2 is now carried out evenly on both sides of the veneer 31, so that its position is preserved.
• an external vacuum source can also be connected to the nozzle 37.
• FIG. 8 Another embodiment of a braking device according to claim 10 is shown in Figure 8.
• a drivable pulley 41 is arranged below the transport path at a short distance between two adjacent belts 16, 24 off-center in approximately 2/3 of the width of the feed device 1.
• the upper tangent of the disk 41 is aligned with the transport path, the axis of rotation is perpendicular to the transport direction.
• a rotatably mounted disk 42 is fastened to a stamp 43.
• the axis of rotation of the disc 42 is perpendicular above and parallel to the axis of rotation of the disc 41.
• the punch 43 can be driven up and down, e.g. via pneumatics or electromagnet.
• the disk 41 is constantly driven slowly, for example by a geared motor 44.
• the direction of rotation of the disk 41 corresponds to the transport direction, the circumferential speed is much slower than the transport speed of the belt system.
• the punch 43 extends so that the pane 42 presses the veneer 31 against the pane 41. Due to the low peripheral speed of the disc 41, the veneer 31 is braked on one side and thus warped into an inclined position. As soon as the required inclined position is reached, the punch 43 moves in and releases the veneer 31 so that it is transported to the carrying belt 15 in the intended inclined position.
• a discharge device 4 according to claim 6 is shown as a detail in FIG.
• the round belts are guided by the pulleys 48 on the drivable shaft 49 via the deflection 47 and back.
• the pulleys 48 have different diameters; their arrangement is such that the inclined position of the veneers 31 in the dryer 2 and cooler 3 is reversed.
• the shaft 49 is mounted at an angle such that the upper edge of the belts 46 guided on the pulleys 48 are aligned with the transport path.
• the shaft 49 is coupled to a drive 50.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Drying Of Solid Materials (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)
• Veneer Processing And Manufacture Of Plywood (AREA)
• Ink Jet (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=7900591

Family Applications (1)

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Family Cites Families (15)

• 1999
  • 1999-03-11 DE DE19910832A patent/DE19910832C1/de not_active Expired - Fee Related
• 2000
  • 2000-02-19 ES ES00909220T patent/ES2220418T3/es not_active Expired - Lifetime
  • 2000-02-19 BR BR0008864-1A patent/BR0008864A/pt not_active IP Right Cessation
  • 2000-02-19 DE DE50006335T patent/DE50006335D1/de not_active Expired - Lifetime
  • 2000-02-19 CA CA002371552A patent/CA2371552C/fr not_active Expired - Fee Related
  • 2000-02-19 JP JP2000604168A patent/JP3754894B2/ja not_active Expired - Fee Related
  • 2000-02-19 WO PCT/EP2000/001383 patent/WO2000053984A1/fr active IP Right Grant
  • 2000-02-19 AT AT00909220T patent/ATE266182T1/de active
  • 2000-02-19 US US10/019,423 patent/US6581300B1/en not_active Expired - Fee Related
  • 2000-02-19 PT PT00909220T patent/PT1161647E/pt unknown
  • 2000-02-19 DK DK00909220T patent/DK1161647T3/da active
  • 2000-02-19 EP EP00909220A patent/EP1161647B1/fr not_active Expired - Lifetime
  • 2000-03-08 TW TW089104139A patent/TW469337B/zh not_active IP Right Cessation

Non-Patent Citations (1)

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