EP3976331A1 - Verfahren und vorrichtung zur vorwärmung einer pressgutmatte - Google Patents
Verfahren und vorrichtung zur vorwärmung einer pressgutmatteInfo
- Publication number
- EP3976331A1 EP3976331A1 EP20725482.2A EP20725482A EP3976331A1 EP 3976331 A1 EP3976331 A1 EP 3976331A1 EP 20725482 A EP20725482 A EP 20725482A EP 3976331 A1 EP3976331 A1 EP 3976331A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- steam
- mat
- pressed material
- air mixture
- material mat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000463 material Substances 0.000 title claims abstract description 81
- 238000010438 heat treatment Methods 0.000 title claims abstract description 77
- 238000000034 method Methods 0.000 title claims abstract description 38
- 239000000203 mixture Substances 0.000 claims abstract description 76
- 239000002023 wood Substances 0.000 claims abstract description 16
- 239000012530 fluid Substances 0.000 claims abstract description 9
- 238000004519 manufacturing process Methods 0.000 claims description 43
- 239000010410 layer Substances 0.000 claims description 25
- 238000003825 pressing Methods 0.000 claims description 14
- 101100491335 Caenorhabditis elegans mat-2 gene Proteins 0.000 claims description 9
- 239000002344 surface layer Substances 0.000 claims description 8
- 238000005056 compaction Methods 0.000 claims 1
- 230000008569 process Effects 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 229920002522 Wood fibre Polymers 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 239000002025 wood fiber Substances 0.000 description 4
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 239000003292 glue Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 239000011093 chipboard Substances 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 239000011094 fiberboard Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000008092 positive effect Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 235000013580 sausages Nutrition 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000003892 spreading Methods 0.000 description 2
- 230000007480 spreading Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 102100040428 Chitobiosyldiphosphodolichol beta-mannosyltransferase Human genes 0.000 description 1
- 238000010793 Steam injection (oil industry) Methods 0.000 description 1
- 238000004378 air conditioning Methods 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- AYEKOFBPNLCAJY-UHFFFAOYSA-O thiamine pyrophosphate Chemical compound CC1=C(CCOP(O)(=O)OP(O)(O)=O)SC=[N+]1CC1=CN=C(C)N=C1N AYEKOFBPNLCAJY-UHFFFAOYSA-O 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/08—Moulding or pressing
- B27N3/24—Moulding or pressing characterised by using continuously acting presses having endless belts or chains moved within the compression zone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N1/00—Pretreatment of moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/08—Moulding or pressing
- B27N3/18—Auxiliary operations, e.g. preheating, humidifying, cutting-off
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
- B30B15/06—Platens or press rams
- B30B15/062—Press plates
- B30B15/064—Press plates with heating or cooling means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
- B30B15/30—Feeding material to presses
- B30B15/302—Feeding material in particulate or plastic state to moulding presses
- B30B15/308—Feeding material in particulate or plastic state to moulding presses in a continuous manner, e.g. for roller presses, screw extrusion presses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
- B30B15/34—Heating or cooling presses or parts thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B30—PRESSES
- B30B—PRESSES IN GENERAL
- B30B5/00—Presses characterised by the use of pressing means other than those mentioned in the preceding groups
- B30B5/04—Presses characterised by the use of pressing means other than those mentioned in the preceding groups wherein the pressing means is in the form of an endless band
- B30B5/06—Presses characterised by the use of pressing means other than those mentioned in the preceding groups wherein the pressing means is in the form of an endless band co-operating with another endless band
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/02—Manufacture of substantially flat articles, e.g. boards, from particles or fibres from particles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/04—Manufacture of substantially flat articles, e.g. boards, from particles or fibres from fibres
Definitions
- the invention relates to a method for preheating a pressed material mat before it enters a press, in particular in the course of the production of wood-based panels, the pressed material mat running through a double-belt preheating device with an upper endlessly circulating, gas-permeable conveyor belt and a lower endlessly circulating, gas-permeable conveyor belt, wherein the pressed material mat (in the double-belt preheater) is exposed to a heated fluid containing steam and thereby heated.
- the invention also relates to a double-belt preheating device for heating a pressed material mat and a system for producing wood-based panels.
- the pressed material mat to be heated (which is also simply referred to as “mat”) is preferably a pressed material mat for the production of wood-based panels. In principle, however, the heating of other pressed material mats or material webs is also recorded.
- a pressed material mat for the production of wood-based panels usually consists of chips or fibers, in particular wood chips or wood fibers, preferably glued wood chips or wood fibers which, for. B. be sprinkled on a scatter belt conveyor or the like to a press mat.
- a continuous pressed material mat and consequently a pressed material mat strand is generated, which passes through a double belt preheater for heating and then in a press, for. B. in a continuously operating Double belt press, is pressed into a plate or a plate strand using pressure and heat.
- a particularly important property of a wood-based panel is the sealing profile over the panel thickness, which can be influenced in the desired direction during panel production in the press by setting the heating plate temperatures, the pressing pressures and the setting of the press gap.
- the relevant settings of the hot press e.g. B. a continuously operating double belt press, are referred to as a press program.
- the press program of the continuous press can be adapted so that higher densities are achieved in the area of the cover layers.
- the press program of the continuous press can be adjusted so that a higher density is achieved in the center of the panel.
- the aim in panel production is to achieve the desired and previously specified panel properties or to keep them above the limit value and at the same time to reduce production costs, in particular by saving wood and glue.
- the production costs can be reduced by a simultaneous maximization of the production capacity.
- Various production parameters such as the amount of glue, the mat moisture and the pressing program (to optimize the shape of the density profile) are optimized. These measures relate to the operation of the press, in which the mat to be pressed is pressed into a plate using pressure and heat in a specific pressing program.
- the mat of material to be pressed is preheated in a preheating device before the actual pressing process.
- z. B. to increase the production capacity, are in the production, z. B. used in MDF production, preheaters in which the pressed material mat z. B. acted upon with a heated fluid (steam or a steam-air mixture) and is thereby heated.
- a heated fluid steam or a steam-air mixture
- moist air such as moist air.
- the application of steam saturated steam or superheated steam without air content
- the mat is preheated with the help of a steam-air mixture (moist air) as a rule in a double-belt preheating device, in which the pressed material mat is flowed through with a steam-air mixture with a set dew point.
- a steam-air mixture moist air
- the moist air is fed to the mat on the upper or lower side and sucked off on the opposite side, with the major part of the steam contained in the mixture condensing in the mat and heating the mat to the dew point set in the moist air (equal to the preheating temperature) becomes.
- the preheating temperature is usually not more than 75 ° C in order to prevent the glue from pre-hardening in the press before the panel has reached its final thickness. Overall, such steam-air preheating can increase the production capacity through the heat input in front of the press.
- the preheating with steam which is also known as an alternative, generally leads to heating only of the cover layers of the pressed material mat or to heating of limited portions of the mat on the upper and lower sides.
- a temperature of approx. 100 ° C is usually reached on the mat surface, which depends on the supplied
- the amount of steam falls in a more or less wide transition area to the (initial) temperature of the mat on the forming line and consequently before entering the preheating device.
- Such a preheating process by (two-sided) steam injection also leads to an overall increase in production capacity due to the amount of heat introduced into the mat, which is usually less than with uniform preheating with humid air (steam-air mixture).
- a method for preheating grit to a predeterminable preheating temperature in the course of the Fier ein of Flolzwerkstoffplatten by pressing a grit mat in a continuous press or a cycle press is z. B. from DE 44 23 632 A1.
- Preheating is carried out with an air-conditioned fluid consisting of air and water vapor, which flows through the grit.
- the fluid has a temperature that is the dew point difference higher than the dew point and the flow rate of the fluid on the one hand, the dew point on the other hand and also the dew point difference are selected so that the specified preheating temperature of the heated spreading material is set. Condensation of the water vapor in the grit is accepted and the humidity of the heated grit is adjusted, if necessary, by additional process measures.
- DE 197 01 596 C2 describes a method and a system for preheating pressed material mats made from glued grit, the pressed material mat being subjected to a flow treatment in a preheating system in which it is exposed to an air-conditioned fluid consisting of air and water vapor at a temperature of below 100 ° C with a set dew point and a set dew point difference.
- the pressed material mats are in the direction of the mat thickness from above and below simultaneously with fluid with the same air conditioning and in the same way specific mass flows flows through, with condensation fronts forming in the pressed material mats, which migrate towards one another in the pressed material from the surface of the pressed material mat and from the lower surface of the pressed material mat.
- the treatment of a litter mat with a steam-air mixture is also known in connection with the production of biodegradable insulation boards (cf. DE 196 35 410 A1).
- the mat or fleece is first compressed to the desired plate thickness and then a steam-air mixture is introduced into the compressed fleece in a heating zone over a period of 10 to 20 seconds, avoiding pre-hardening of the binding agent.
- a stream of hot air is passed through the compacted fleece for curing and drying.
- the system known in this respect is therefore not used to preheat a mat for subsequent pressing in a separate press, but in the double belt press both preheating via a steam-air mixture and curing and drying of the mat using hot air takes place.
- Wood-based panels are created.
- the invention teaches in a generic method for preheating a pressed material mat that the pressed material mat in the double-belt preheater initially in a first stage with a first heating unit with a steam-air mixture with a set dew point (ie with a set dew point temperature) and usually a (set) temperature of less than 100 ° C is applied, which flows through the mat from one side or surface to the opposite side or surface and is thereby heated over the entire mat thickness to a first temperature T1 and that the Pressed material mat in the double-belt preheating device is then applied in a second stage with a second heating unit on both sides with (pure) steam or with a steam-air mixture and thereby only the surface layers near the surface are heated to a second temperature T2, which is higher than the first Temperature is T1. Steam particularly means water vapor.
- a steam-air mixture flows through the mat in the first stage and steam is applied on both sides in the second stage.
- preheating with a (first) steam-air mixture with a set dew point and a (set) temperature of less than 100 ° C can take place in the first stage, and in the second stage a (second) Steam-air mixture, which, however, has a higher dew point and / or a higher temperature than the first steam-air mixture of the first stage, so that the surface layers near the surface are heated in this second stage.
- the invention is based on the knowledge that preheating with a steam-air mixture (humid air) on the one hand and preheating with steam (saturated steam or superheated steam) act differently and lead to different effects in the production process, so that the production process is combined , two-stage approach can be optimized overall. Because with the help of preheating by means of a steam-air mixture, a significantly higher amount of heat can be introduced into the entire mat when it is heated to the dew point than with conventional steam preheating, which leads exclusively or essentially to heating of the top layers. This allows the production capacity to be increased more by preheating using a steam-air mixture than with a steam preheating process.
- preheating the entire mat by means of moist air leads to a more or less pronounced 'flattening' of the density profile, since a preheated mat can be compacted with less pressure because both mat moisture and mat temperature are raised during preheating.
- the disadvantage is that the cover layer density decreases to a greater or lesser extent, with correspondingly negative effects on the flexural rigidity, for example.
- preheating with steam causes the top layers to become warmer and more humid and thus also softer, and so very distinctive top layers of high density can be created while the cold and "hard" middle of the mat leads to rather low mat densities in the middle of the panel.
- the production capacity can only be increased slightly because of the low heat input in the middle of the mat.
- higher amounts of steam are injected into the mat cover layers in order to increase production capacity, there is a risk that an ever larger proportion of the weight per unit area of the mat is "consumed” in the cover layers and that there is no longer enough material available in the middle of the plate to cover the to achieve the mat density required for the transverse tension.
- the two-stage preheating by means of a steam-air mixture in a first stage and by means of steam (or alternatively also a steam-air mixture with a higher dew point) in the second stage increases both the production capacity and high material savings and an optimal Density profile (based on the important panel properties such as transverse tensile strength and flexural strength) is achieved simultaneously in a common preheating process and in a single preheating device.
- the previously "opposing goals”, namely high production capacity, high material savings and an optimal density profile, are achieved together in a combined process.
- the preheating takes place in the first stage with a steam-air mixture and consequently with moist air with a set dew point and set temperature which is the so-called dew point difference above the dew point.
- the dew point (which is also referred to as the dew point temperature) denotes the temperature at which the air in the steam-air mixture is just saturated with the amount of steam present (in particular water vapor). Below the dew point, condensation of the water vapor occurs as a result of oversaturation, so that the water vapor condenses like a dew. At the dew point, the relative humidity is 100% and the air is (just) saturated with water vapor.
- the dew point or the dew point temperature (and, if applicable, the temperature or dew point difference) of the steam-air mixture can be set in a targeted manner using known means and measures.
- z. B. air z. B. with the help of a heat exchanger
- a mixing device with (fresh) steam (z. B. water vapor) in the desired ratio.
- the steam condenses in the mat and the mat is preferably heated to the set dew point, i.e. the preheating temperature T1 of the mat in the first stage preferably corresponds to the dew point temperature of the steam-air mixture used, so that the pressed material mat is preferably heated to a temperature T1 of 50 ° C to 85 ° C, preferably 60 ° C to 75 ° C, in the first stage.
- the steam-air mixture flows through the press mat in the first stage from one surface to the opposite surface, preferably by feeding it on one surface (e.g. the top) and on the opposite side (e.g. the bottom) is sucked off.
- it may be sufficient in the first stage to provide a flow through the mat in one direction only in a single zone, e.g. B. from top to below or alternatively from below to above.
- the first stage for steam-air preheating consists of at least two zones arranged one behind the other, in which the steam-air mixture with the set dew point flows through the mat in alternating, opposite directions. So z. B.
- the steam-air mixture pressed from above into the mat and sucked from below from the mat and in the second zone pressed from below into the mat and sucked out of the mat from above preferably the same Mixture is used with the same parameters, in particular identical dew point. In this way, a particularly homogeneous heat input and thus even preheating of the mat over the entire thickness can be achieved.
- the mat which is preheated to temperature T1 over the entire thickness in the first stage for the purpose of increasing capacity, is consequently further heated to temperature T2 in the second step in the area of the cover layers, preferably by means of steam, so that with the help of the mats with warmer and softer cover layers, a particularly high cover layer density with the described advantages of the board properties can be achieved.
- the mat is consequently completely traversed by a steam-air mixture in the first stage, in the second stage the mat is preferably acted upon by steam from both sides at the same time without opposite suction.
- a steam-air mixture instead of steam can also be used in the second stage, which is used for heating the outer layer.
- a steam-air mixture and consequently moist air with a higher dew point and optionally higher temperature is used in the second stage, ie the steam-air mixture has a higher dew point and / or a higher temperature or respectively in the second stage Dew point difference as the steam-air mixture in the first stage, which is responsible for the even heating of the mat.
- the steam-air mixture can be pressed into the mat from both sides at the same time, just like with a pure steam application.
- the steam-air mixture in the second stage flows through the mat in one direction and is consequently pressed into the mat from one side and sucked off on the other side.
- the invention also relates to a double-belt preheating device for heating a pressed material mat, in particular with or according to a method of the type described.
- This double-belt preheating device has an upper, continuously circulating, gas-permeable conveyor belt and a lower, continuously circulating, gas-permeable conveyor belt, between which a treatment gap is formed, through which the mat can be passed along the transport direction (by means of the driven conveyor belts).
- the double-belt preheating device has a heating unit, namely a first heating unit, which is designed as a steam-air supply device and with which the pressed material mat (in a first treatment stage) with a steam-air mixture with an adjustable dew point (and adjustable temperature ) can be acted upon, this steam-air mixture (moist air) flowing through the mat from one surface to the opposite surface and thereby heating the mat over the entire thickness of the mat, preferably to the set dew point of the steam-air mixture.
- the double-belt preheating device additionally has a second heating unit which is arranged downstream of the first heating unit and consequently the steam-air supply device in the transport direction and which is used to treat the pressed material mat in a second treatment stage.
- the second heating device is preferably designed as a steam supply device with which (pure) steam (preferably water vapor) can be applied to the mat for heating only the surface layers close to the surface.
- the second heating device can, however, be designed as a steam-air supply device, with which the mat for heating only the cover layers close to the surface with a (second) steam-air Mixture can be acted upon, which has a higher dew point and / or a higher temperature than the (first) steam-air mixture of the first heating unit.
- the first heating unit which is designed as a steam-air supply device, preferably has at least one supply-suction pair with a supply, e.g. B. a feed box, on one side of the mat and a suction, z. B. a suction box on the opposite side of the mat.
- the supply and / or the discharge can corresponding boxes, registers and / or plates, e.g. B. perforated plates, grid plates or the like.
- several such devices are arranged distributed over the width of the mat, so that the application and / or suction profile is variable over the width of the mat.
- the first heating unit not only has a single supply-suction pair for a flow through the mat in one direction, but several supply-suction pairs arranged one behind the other are provided, which are preferably designed for opposite flow directions, so that the mat is traversed one after the other in at least two consecutively arranged zones in opposite directions.
- z. B. on the top first a first feed, z. B. a first feed box and on the opposite bottom a first suction, z. B. a first suction box can be arranged.
- a second feed, z. B. a second feed box and on the top a second suction, z. B. a second suction box can be provided.
- the reverse arrangement is also possible.
- the second heating unit is preferably designed as a (pure) steam supply device and has at least one supply pair with one supply on each side of the mat, e.g. B. on a feed box. This can be used from both sides via the feeders, for. B. feed boxes, simultaneously press steam (or alternatively a steam-air mixture) into the mat from both sides in order to heat the top layers.
- the second heating unit (e.g. as a steam-air supply unit) can have several supply-suction pairs arranged one behind the other, which are designed for opposite flow directions, so that the construction of the second heating unit essentially corresponds to the construction of the first heating unit may correspond, but the second heating unit is designed for the application of a steam-air mixture with a higher dew point.
- the conveyor belts of the preheating device are preferably designed as sieve belts.
- the double-belt preheating device can optionally be equipped with a compacting device for compacting the mat, this compacting device preferably being arranged downstream of the second heating unit. There is consequently first of all preheating with the aid of the first heating unit and the second heating unit and then optionally compression with the compacting device.
- a compacting device for compacting the mat, this compacting device preferably being arranged downstream of the second heating unit.
- Compacting roller with at least one power means e.g. B. a press cylinder
- at least one power means e.g. B. a press cylinder
- the press cylinders it can be, for. B. act to hydraulic cylinders.
- a re-compression to vent the mat of material to be pressed, with the aim of displacing air on the mat, so that the subsequent pressing process in the downstream press is optimized and the risk of blowouts is reduced. In this way, an increased feed rate of the system and thus an even higher profitability is achieved.
- the double-belt preheating device described and its operation for preheating the pressed material mat are in the foreground.
- the invention also relates to a plant for the production of wood-based panels, with at least one scattering device for producing a pressed material mat and with a double-belt preheating device of the type described and with a press for pressing the preheated pressed material mat.
- This press which is preferably designed as a continuously operating double belt press, is consequently preferably arranged behind the double belt preheating device according to the invention.
- the double-belt preheating device is therefore not used to manufacture a finished product, but only to preheat a pressed material mat within the manufacturing process, i.e. H. the preheated mat of material to be pressed is then pressed into the finished product in a separate press using pressure and heat.
- the press downstream of the preheating device is preferably designed as a double belt press.
- She has z. B. an upper heating plate and a lower heating plate and in the upper part of the press and in the lower part of the press endlessly circulating press belts, for. B. steel press belts.
- These press belts are z. B. with the interposition of rolling element assemblies (z. B. roller bars) supported on the heating plates or press plates.
- One of the heating plates or both heating plates are acted upon by press cylinders that are attached to the Press frame (z. B. on the press frame) are supported.
- the preheating device according to the invention can then consequently be integrated into a conventional manufacturing process and combined with known double belt presses.
- the preheating device is particularly preferred in the manufacture of fiberboard, e.g. B. MDF board (Medium Densified Fiber) used, d. H. A pressed material mat made of wood fibers is preheated. Alternatively, it can also be used for chipboard and OSB panels and consequently the preheating of chipboard and OSB mats.
- fiberboard e.g. B. MDF board (Medium Densified Fiber) used, d. H.
- a pressed material mat made of wood fibers is preheated.
- it can also be used for chipboard and OSB panels and consequently the preheating of chipboard and OSB mats.
- FIG. 1 shows a section of a plant for the production of
- FIG. 2 shows a schematically simplified side view of a double-belt preheating device from the system according to FIG. 1,
- a simplified system for the setting of Flolzwerkstoffplatten is shown in a continuous flow.
- the grit to be compacted for example, wood fibers
- the grit mat produced in this way is pretreated in a double belt preheating device 3 and then in a continuously operating press 4 using pressure and heat to form a plate or a plate-shaped strand, e.g. B. a fiber board (preferably MDF board) pressed.
- the press 4 is preferably designed as a double belt press, which has an upper heating plate and a lower heating plate and endlessly rotating press belts (e.g.
- the mat 1 to be pressed is preheated with the aid of the preheating device 3 which is only indicated in FIG. 1 and which is also shown in greater detail in FIG.
- This has an upper, endlessly circulating, gas-permeable conveyor belt 5a, for. B. a sieve belt 5a, and a lower, endlessly revolving, gas-permeable conveyor belt 5b, for. B. a screen belt 5b.
- the conveyor belts or sieve belts 5a, 5b are each guided around several rollers or rollers 6, of which at least for the upper part and the lower part one roller is designed as a drive roller.
- a treatment gap is formed between the conveyor belts 5a, 5b, through which the mat 2 is guided along the transport direction X from an inlet E to an outlet A.
- the area of the conveyor belt 5a, 5b which extends from the inlet E to the outlet A and in which the pressed material mat 2 is consequently guided is referred to as the forerun V and the subsequent area of the belts starting at the outlet A to the inlet E forms the Return R, which in turn merges into flow V at inlet E.
- the double-belt preheating device 3 has a first heating unit 7 immediately behind the inlet E, which is designed as a steam-air supply device and with which the pressed material mat can be acted upon with a steam-air mixture with an adjustable dew point, which the mat from a surface to the opposite surface and thus heated over the entire mat thickness.
- the first heating unit 7 has several supply-suction pairs 8 arranged one behind the other, each having a supply 8a and a suction 8b arranged on the opposite side of the mat, whereby these can be designed as a supply box 8a and suction box 8b. Details are not shown.
- the first feed-suction pair 8 has an upper feed 8a and a lower suction 8b, while the second feed-suction pair 8 has a lower feed 8a and an upper suction 8b.
- two zones 8 arranged one behind the other are consequently implemented, in which a steam-air mixture is pressed through the mat 2 in opposite directions and sucked through the mat.
- the pressed material mat 2 is consequently in a first stage formed by the first heating unit 7 with a steam-air mixture with a set dew point (and set temperature) acted upon, which flows through the mat from one surface to the opposite surface and thereby heats it over the entire mat thickness to a first temperature T1 which corresponds (approximately) to the (preset) dew point temperature of the steam-air mixture.
- the preheating device 3 has a second heating unit 9 which is arranged in the transport direction X behind the first heating unit 7.
- this is designed as a steam supply device with which the mat 2 can be acted upon with (pure) steam for heating only the cover layers close to the surface.
- the steam supply device 9 has a supply pair with a supply 9a for the steam on both sides of the mat, these supplies 9a z. B. can be designed as feed boxes. With the inlets 9a steam (z. B. water vapor) is simultaneously pressed into the mat from both sides, the steam z. B. may have a temperature of 100 ° C or more.
- this second heating unit 9 steam is pressed into the mat 2 on both sides and as a result only the surface layers are heated to a second temperature T2, which is higher than the first temperature T1 to which the mat is heated in the first heating unit 7.
- the preheating device shown in FIG. 2 is followed by a two-stage preheating of the press mat, in the first stage with the aid of a steam-air mixture, with which the press mat 2 is heated to a first temperature T1 evenly over the entire mat thickness.
- first temperature T1 evenly over the entire mat thickness.
- second stage only the surface layers near the surface are heated further to the second temperature T2.
- the heating in the first stage results in a high input of heat, which leads to increased production capacity.
- the increase in temperature in the In the course of the subsequent pressing process, outer layers close to the surface lead to panels with improved properties, in particular with regard to flexural strength and transverse tensile strength.
- FIGS. 3a, 4a, 5a and 6a each show a temperature profile over the thickness of the plate, i.e. H. the temperature of the mat entering the press and the temperature of the plate after the press are plotted as a function of the location within the plate in percent based on the plate thickness.
- a plate thickness of z. B. 16 mm means 0% 0 mm and 100% 16 mm, i.e. H. the value 0% relates to one panel surface and the value 100% relates to the opposite panel surface and the values in between relate to the interior of the panel.
- the thickness of the mat is of course significantly reduced in the pressing process in the continuous press, e.g. B. on the plate thickness of 16 mm.
- FIGS. 3b, 4b, 5b and 6b each show density profiles, on the one hand for the mat of material to be pressed before it enters the press (e.g. DPo in FIG. 3b) and on the other hand for the finished pressed plate behind the press, i.e. . H. the density of the plate is plotted as a function of the plate thickness or of the location within the plate based on the plate thickness.
- FIGS. 3a and 3b initially show the conditions when a fibreboard (e.g. MDF board) is positioned without any preheating before the press.
- the mat density P M is e.g. B. 120 kg / m 3 , homogeneously over the entire thickness of the pressed material mat (density profile DPo).
- the density profile DP p also shown in FIG. 3b, occurs, the plate having an average density pp of z. B. 550 kg / m 3 .
- the panel has a relatively low density in the center of the panel and a relatively high density in the outer cover layers.
- Figures 4a, 4b show the influence of the heating of the entire press mat with a basically known preheating by means of a steam-air mixture (abbreviated here in the indices with DL), which z. B. has a dew point of 70 ° C, so that the mat is preheated over the entire width to a temperature Ti of (about) 70 ° C.
- 4a again shows the homogeneous temperature profile TPo with the mat temperature To after the scattering station and consequently before the preheating device at 30.degree.
- the mat temperature Ti is shown behind the preheating device, ie there is essentially uniform preheating to about 70 ° C. (temperature profile TPDL) over the thickness.
- FIG. 4b again shows the density profile DPP of the finished panel without preheating (as in FIG. 3b).
- the density profile DPDL is shown, which is established due to the preheating described with the steam-air mixture. It can be seen that the density is increased in the middle of the mat, which has a positive effect on the transverse tension. On the other hand, however, the surface layer densities decrease compared to processing without preheating, which is undesirable.
- FIGS. 5a, 5b show the influence of preheating of the cover layers by conventional application of steam on both sides.
- Figures 6a, 6b show the influence of the two-stage preheating according to the invention by means of initially a steam-air mixture in a first stage and then by means of steam application in a second stage.
- the mat temperature is raised to the temperature Ti over the entire thickness of the mat and the homogeneous temperature profile TPsi is achieved.
- the steam is applied to raise the temperature to temperature T2 of approximately 100 ° C. only in the area of the outer layers, and the temperature profile TP S2 is reached.
- the density profile DP K resulting in the subsequent pressing process by combined preheating is again shown in FIG. 6b in comparison with a density profile DP P without preheating. From Fig.
- a system or its preheating device shown by way of example in the figures also has conventional means for generating, setting, supplying and controlling or regulating the steam and the steam-air mixture, e.g. B. heat exchangers, mixing devices, etc. This allows the parameters of the steam and in particular the steam-air mixture to be set, in particular the dew point and the temperature or dew point difference.
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- Dry Formation Of Fiberboard And The Like (AREA)
Abstract
Description
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Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE102019114021.8A DE102019114021B3 (de) | 2019-05-24 | 2019-05-24 | Verfahren und Vorrichtung zur Vorwärmung einer Pressgutmatte |
PCT/EP2020/062857 WO2020239394A1 (de) | 2019-05-24 | 2020-05-08 | Verfahren und vorrichtung zur vorwärmung einer pressgutmatte |
Publications (3)
Publication Number | Publication Date |
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EP3976331A1 true EP3976331A1 (de) | 2022-04-06 |
EP3976331B1 EP3976331B1 (de) | 2024-02-07 |
EP3976331C0 EP3976331C0 (de) | 2024-02-07 |
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EP20725482.2A Active EP3976331B1 (de) | 2019-05-24 | 2020-05-08 | Verfahren und vorrichtung zur vorwärmung einer pressgutmatte |
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Country | Link |
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EP (1) | EP3976331B1 (de) |
CN (1) | CN113748004B (de) |
DE (1) | DE102019114021B3 (de) |
WO (1) | WO2020239394A1 (de) |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3640682A1 (de) * | 1986-11-28 | 1988-06-09 | Baehre & Greten | Verfahren und vorrichtung zum kontinuierlichen vorwaermen eines vlieses fuer die herstellung von span-, faser- oder dergleichen platten |
DE4415276A1 (de) * | 1994-04-30 | 1995-11-02 | Siempelkamp Gmbh & Co | Verfahren zur Herstellung von Holzwerkstoffplatten |
DE4423632A1 (de) * | 1994-07-06 | 1996-01-11 | Siempelkamp Gmbh & Co | Verfahren zum Vorwärmen von Streugut auf eine vorgebbare Vorwärmtemperatur im Zuge der Herstellung von Holzwerkstoffplatten |
DE19701595B4 (de) * | 1996-02-15 | 2004-09-09 | Siempelkamp Maschinen- Und Anlagenbau Gmbh & Co. Kg | Anlage für die Vorwärmung einer Preßgutmatte im Zuge der Herstellung von Holzwerkstoffplatten, insbesondere von Spanplatten |
DE19635410C2 (de) * | 1996-08-31 | 2003-02-27 | Siempelkamp Gmbh & Co Maschine | Vorrichtung zum Verpressen eines Vlieses zu einem Plattenstrang |
DE10206861A1 (de) * | 2002-02-18 | 2003-09-04 | Siempelkamp Masch & Anlagenbau | Verfahren zum Pressen und Aushärten von Pressgutmatten im Zuge einer kontinuierlichen Herstellung von Spanplatten, Faserplatten u. dgl. Holzwerkstoffplatten |
DE102005016408A1 (de) | 2005-04-08 | 2006-10-12 | Dieffenbacher Gmbh + Co. Kg | Verfahren zur kontinuierlichen Vorwärmung eines Vlieses oder einer Matte und Vorrichtung zur Durchführung des Verfahrens |
DE102005046879A1 (de) * | 2005-09-29 | 2007-04-05 | Dieffenbacher Gmbh + Co. Kg | Verfahren und Vorrichtung zur Vorwärmung einer gestreuten Pressgutmatte bei der Herstellung von Holzwerkstoffplatten |
DE102008057557A1 (de) * | 2008-11-15 | 2010-05-20 | Dieffenbacher Gmbh + Co. Kg | Verfahren und Kalibrier- und Verschweißeinheit zur Herstellung von flexiblen Dämm-und/oder Schallschutzplatten oder flexiblem Halbzeug zur Weiterverarbeitung in Heißpressen |
EP2213432A1 (de) * | 2009-01-29 | 2010-08-04 | Imal S.R.L. | Vorrichtung zur Befeuchtung von Matten basierend auf losem Holzmaterial |
IT1401172B1 (it) * | 2010-07-02 | 2013-07-12 | Imal Srl | Apparato per il riscaldamento di materassi a base di materiale legnoso incoerente |
DE102015121869A1 (de) * | 2015-12-15 | 2017-06-22 | Siempelkamp Maschinen- Und Anlagenbau Gmbh | Verfahren und Anlage zur kontinuierlichen Entwässerung von Wasser enthaltenem Gut, insbesondere zur Entwässerung von Braunkohle |
CN110802711A (zh) * | 2019-10-11 | 2020-02-18 | 上海人造板机器厂有限公司 | 用于提高板坯温度的板坯预热方法及装置 |
-
2019
- 2019-05-24 DE DE102019114021.8A patent/DE102019114021B3/de active Active
-
2020
- 2020-05-08 WO PCT/EP2020/062857 patent/WO2020239394A1/de unknown
- 2020-05-08 EP EP20725482.2A patent/EP3976331B1/de active Active
- 2020-05-08 CN CN202080030287.6A patent/CN113748004B/zh active Active
Also Published As
Publication number | Publication date |
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CN113748004B (zh) | 2023-04-28 |
WO2020239394A1 (de) | 2020-12-03 |
CN113748004A (zh) | 2021-12-03 |
DE102019114021B3 (de) | 2020-11-12 |
EP3976331B1 (de) | 2024-02-07 |
EP3976331C0 (de) | 2024-02-07 |
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