Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
  • F26B21/004—Nozzle assemblies; Air knives; Air distributors; Blow boxes
• • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
  • F26B21/02—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
  • F26B21/02—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure
  • F26B21/04—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure partly outside the drying enclosure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B23/00—Heating arrangements
  • F26B23/02—Heating arrangements using combustion heating
• • 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 plates, which are guided in floors by a drying device, wherein the plates are brought into the drying device by means of impingement jet ventilation with drying air in contact and wherein the impingement jet ventilation is ensured by means of cross-ventilated nozzle boxes.
• the invention also relates to an apparatus for drying plate-like materials, in particular plasterboard.
• the drying of such plate-like materials is preferably carried out by a predominantly convective heat transfer in the form of the overflow of heated air.
• the usually arranged over several floors plates are guided by means of conveyors such as roller conveyors or Siebbändem through the dryer.
• drying systems are usually operated in recirculation mode.
• the drying air is introduced several times to the plates and reheated after each contact. In this way, the air increasingly accumulates moisture, only a small portion of the drying air is discharged to the environment as exhaust air to dissipate moisture and fumes into the environment.
• a distinguishing feature of various types of dryers is the type of air flow over the material to be dried.
• the air can be fed to the plate essentially in the form of transverse ventilation, longitudinal ventilation, or so-called impingement jet ventilation.
• the drying air In transverse ventilation, the drying air is passed from the side, transversely to the conveying direction of the plate-like material, over the material to be dried. Since the drying air increasingly cools as it travels across the material to be dried, this results in different drying speeds across the width. Therefore, this method is not applied to sensitive materials such as plasterboard.
• the drying air In longitudinal aeration, the drying air travels a long way along the longitudinal axis of the dryer, overflows the plate, dries it and thus cools down strongly. The drying air can thus at low temperatures, particularly low energy near the dew point of the
• CONFIRMATION COPY Drying air to be dissipated For heating fresh air by means of a heat exchanger can then be used specifically condensation heat.
• drying air is introduced from the side of the drying plant into drying chambers, also referred to as nozzle boxes, and blown via air outlet nozzles vertically onto the surface of the material to be dried. From there, this air flows to the opposite side of the drying plant.
• drying chambers also referred to as nozzle boxes
• air outlet nozzles vertically onto the surface of the material to be dried. From there, this air flows to the opposite side of the drying plant.
• a dryer chamber is designed so that the highest possible heat input and the most uniform possible drying over the width of the material to be dried are guaranteed.
• a drying plant in which a two-stage drying process is used.
• the second drying stage is heated with the interposition of a heat exchanger from the exhaust air of the first dryer stage.
• the plates should be in the first dryer stage with high temperature and high humidity and in the second dryer stage with relative be dried low temperature and low humidity.
• the first stage is here longitudinally ventilated, the second stage cross-ventilated.
• a method for drying plates is known, which are guided in floors through a device divided into drying chambers device, wherein the plates are brought in a drying device by impact jet ventilation with the drying air in contact and the impingement jet ventilation by means of cross-ventilated nozzle boxes is guaranteed.
• the drying apparatus is a main drying stage or a final drying stage in a drying plant.
• drying systems for drying veneer or gypsum boards per drying device each have a recirculation fan, which is arranged in the middle of the ceiling box above a drying space receiving the plates.
• the air flow generated by this is uneven, which is due to the limited dimensions of the ceiling box, in which the fan is arranged.
• compensatory measures such as the use of panels and baffles, attempts to compensate for these deficits again.
• the ratio of the suction stroke of the fan, based on its impeller outer diameter is at a value of about 0.36, which, given the relatively small height of the roof box, does not permit uniform air flow.
• this object is achieved in a method of the type mentioned above in that the drying air is supplied by means of at least two side by side arranged in an air flow of the drying air fans, which is generated by a burner which conducts the drying air to the fans.
• the method according to the invention makes it possible to gently dry plate-shaped materials with a low expenditure of energy by means of impingement jet ventilation.
• the drying device comprises a ceiling box in which a burner generates drying air, wherein the ceiling box comprises at least two juxtaposed fans to which the drying air from the Burner can be fed.
• a drying device in which the at least two fans each have a direct drive.
• simply built fans without gears or couplings can be used.
• the at least two fans are each surrounded by a spiral housing.
• the at least two fans each have four-pole motors, in particular asynchronous motors, with a speed of 1500 revolutions per minute.
• the two fans replace a single fan, which has an eight-pole motor with a speed of 750 revolutions per minute.
• Eight-pole motors are more complex to produce and have a lower efficiency than four-pole motors.
• the fans each have an impeller diameter of about 800 mm and are separated by a central partition wall.
• the ratio of the suction height of the fans is at least 0.5, in particular more than 0.8. Due to the optimized flow, the blades of the fan are used more evenly, which increases the efficiency of the fan.
• Another measure for achieving an efficient drying process is that the ratio of the impeller outer diameter of one of the fans to the distance between an impeller and the wall of the ceiling box on the side of the pressure chamber is more than 3.5. Thus, the distance between the air outlet from the impeller of the fan and the dryer wall is sufficiently large to equalize the flow of air.
• Fig. 1 is a longitudinal section of a drying device
• FIG. 2 shows a horizontal sectional view along a section line A - A from FIG. 1.
• Flow direction is indicated by arrows.
• Preheated fresh air is fed to a burner 1 as combustion air.
• the pressure chamber 5 serves to uniformly distribute the air into the individual levels of a drying space 6.
• the air is first pressed into nozzle boxes 7 (only one of which is shown by way of example in FIG. 1), of which they are only accessible via hole nozzles 70 (for example a few hole nozzles 70 shown in Fig.
• the nozzle boxes 7 are made tapered in the flow direction of the air. Above and below the plates 8, the air escaped from the nozzle boxes 7 via the perforated nozzles 70 then flows into a suction chamber 9. A portion of the air, which in total substantially corresponds to the combustion gases, the fresh air and the water vapor produced by the drying, escapes via an exhaust air discharge. At the burner 1, the circulating air closes.
• the area above the pressure chamber 5, the drying chamber 6 and the suction chamber is also referred to as overhead ceiling box eleventh
• fans 4a, 4b are arranged with respect to the burner 1 at a distance to this side by side and separated by a partition 40 from each other. Both fans 4a, 4b are each surrounded by a spiral housing 41. Both fans 4a, 4b are preferably arranged eccentrically in the area between the partition wall 40 and an outer wall 42, 43 of the ceiling box 11, being closer to the outer walls 42, 43 than to the partition wall 40. It has been found that, for reasons of flow dynamics, a more uniform supply of air to the drying air into the pressure chamber 5 is achieved in this way.
• the ratio of the impeller outer diameter of each of the fans 4a, 4b to a distance d between a lateral impeller outlet of the air from the fans 4a and 4b to a wall 50 of the ceiling box 11 above the pressure space 5 is more than 3.5.
• an air guide 12 and a wall 13 are present.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Drying Of Solid Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=66334341

Family Applications (1)

Country Status (10)

Families Citing this family (2)

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• 2018
  • 2018-03-15 DE DE102018002107.7A patent/DE102018002107A1/de active Pending
• 2019
  • 2019-03-15 BR BR112020018344-0A patent/BR112020018344A2/pt unknown
  • 2019-03-15 CN CN201980019301.XA patent/CN111868464A/zh active Pending
  • 2019-03-15 EA EA202092141A patent/EA202092141A1/ru unknown
  • 2019-03-15 CA CA3093485A patent/CA3093485A1/en active Pending
  • 2019-03-15 EP EP19720361.5A patent/EP3765807A1/de active Pending
  • 2019-03-15 US US16/980,476 patent/US12007166B2/en active Active
  • 2019-03-15 KR KR1020207029271A patent/KR20200130728A/ko not_active IP Right Cessation
  • 2019-03-15 WO PCT/EP2019/000080 patent/WO2019174785A1/de unknown
  • 2019-03-15 JP JP2020547354A patent/JP7310054B2/ja active Active

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