METHOD AND DEVICES FOR THE MANUFACTURING OF STRAWBOARDS

Description

[0001] The present invention relates to a method and apparatus for the production of straw boards.

[0002] EP 2 799 639 A1 discloses an insulation board for insulating a building facade, wherein the insulation board is made of straw held together by an adhesive. The adhesive can be glue, in particular plant glue, or starch adhesive. The insulation board is produced by mixing, preferably chopped, straw with the adhesive, lightly pressing the straw-adhesive mixture into an insulation board, and allowing the resulting insulation board to dry. For drying, the insulation board is preferably heated, in particular to a temperature of approximately 25–50 °C.

[0003] DE 198 10 862 A1 discloses a straw insulation board in which the straw fiber length is a maximum of 150 mm, the straw is fibrously shredded, and the closed stem structure is disrupted by longitudinal splitting. The straw fibers are homogeneously mixed with a biodegradable binder, the mixture of straw fibers and binder is slightly mechanically compacted into board material, the board has a minimum thickness of 30 mm, and the bulk density is between 40 and 100 kg / m³. The board is also provided on both sides with a flexible, grid-like natural fiber coating. Preferably, the straw fibers have a length of at least 2 mm or more. The insulation board is manufactured by fibrously shredding the straw and splitting it lengthwise into a fraction with fiber lengths of up to a maximum of 150 mm.The fiber fraction is then homogeneously mixed with a biodegradable binder containing excess water, and the mixture is continuously applied to a binder-impregnated sheet of coating material with minimal deformation. Mixing the fiber fraction with the binder and flame retardant preferably takes place in a mixing device. The homogeneous mixture is then conveyed by a conveyor belt into a mixing silo, which has a discharge roller at its lower end and is positioned above a plate conveyor belt on which the impregnated sheet of coating material is arranged.

[0004] A top layer of coating impregnated with binder is applied to the resulting insulation layer. The entire insulation layer is then conveyed through a heating zone to dry and, if necessary, vulcanize. This is preferably done using a hot air flow process with a hot air temperature of approximately 100°C. During drying, the binder dries and vulcanizes, with the resulting water vapor acting as a heat transfer medium and promoting the vulcanization process. The dried layer is then cut into panels.

[0005] WO 99 / 14022 A1 discloses a device for the production of straw boards according to the preamble of claim 1.

[0006] The object of the present invention is to provide a cost-effective method and a device for the production of straw boards, which ensures a uniform and good quality of the produced straw boards.

[0007] This problem is solved by a device according to claim 1 and a method according to claim 22. Advantageous embodiments of the invention are characterized in the subsequent dependent claims.

[0008] The invention will now be explained in more detail with the aid of an example drawing. The drawing shows: Figure 1: A simplified, schematic representation of the device according to a first embodiment of the invention. Figure 2: A simplified, schematic representation of the device according to a further embodiment of the invention. Figure 3: A simplified, schematic side view of a straw bale dissolving device. Figure 4: A simplified, schematic side view of a weighing device. Figure 5: A perspective view of the weighing device. Figure 6: A simplified, schematic side view of a vibrating trough with a lime feeding device. Figure 7: A perspective view of the hydrated lime feeding device. Figure 8: A longitudinal section of the hydrated lime feeding device. Figure 9: A perspective, half-section view of the hydrated lime feeding device. Figure 10: A simplified, schematic longitudinal section through a mixing device and a cyclone separator according to the invention. Figure 11: A simplified,Schematic cross-section through a multi-level mixer of the mixing unit without intermediate floor Figure 12: Another cross-section through the multi-level mixer without mixer shaft Figure 13: A side view of the multi-level mixer Figure 14: A simplified, schematic side view of the mixing unit and an insulation board pressing unit without a cutting unit Figure 15: A perspective view of an area of ​​the insulation board pressing unit Figure 16: Another perspective view of an area of ​​the insulation board pressing unit without a side wall Figure 17: A perspective view of a throwing device of the insulation board pressing unit Figure 18: A simplified,Schematic side view of a plate press according to a further embodiment of the device according to the invention. Figure 19: Highly simplified and schematic representation of the device according to the invention according to a further embodiment of the invention with further conveying means between the mixing device and the plate press. Figure 20: A simplified, schematic representation of the device according to a further embodiment of the invention. Figure 21: A perspective view of a further weighing device, closing slide in a half-closed position. Figure 22: A perspective view of a screw mixer according to the invention. Figure 23: A sectional view of the screw mixer according to the invention. Figure 24: Part of a top view of the screw mixer according to the invention. Figure 25: Part of a side view of the screw mixer according to the invention.

[0009] The device 1 according to the invention is used for the production of straw boards 12;13. The straw boards 12;13 to be produced are preferably single-layered or monolithic and consist of straw held together by a hardened binder matrix. The binder matrix binds the individual straw strands together.

[0010] According to a first embodiment of the invention ( Fig. 1The device 1 according to the invention serves for the production of insulating straw panels 12 or straw insulation panels 12 and comprises, downstream of one another, a straw bale dissolving device 2, a conveying channel 3, a weighing device 4, a vibrating trough 5, a hydrated lime feeding device 6, preferably a further conveying channel 7, preferably a cyclone separator (50), a mixing device 8 according to the invention, and preferably a further conveying channel 9 and an insulation panel pressing device 10. The device 1 also includes a control device 11 for controlling the manufacturing process.

[0011] Subordinate in the sense of the registration means that the respective facility is passed through after the upstream facility during production.

[0012] The straw bale dissolving device 2 ( Fig. 1 , 2 , 3) serves in a manner known per se to dissolve and loosen a straw bale 15. Preferably the straw bale 15 consists of cereal straw, preferably wheat straw, or hemp straw or reed straw or cattail straw (=Typhastroh).

[0013] Straw generally refers to threshed and dry stalks and / or leaves of plants.

[0014] Such straw bale breakers 2 are used, for example, in horse stables. The straw bales 15 are broken up and loosened by means of the straw bale breaker 2 without the straw stalks being crushed.

[0015] The straw bale dissolving device 2 preferably comprises, in a manner known per se, a housing 16, a milling belt 17, a support plate 18, a receiving hopper 19, and a discharge auger 20. The milling belt 17, the support plate 18, and the receiving hopper 19 are arranged in the housing 16. The discharge auger 20 is partially arranged in the housing 16 and opens to the surrounding environment or leads to the outside.

[0016] To break up and loosen the straw, the bale 15 is placed on the continuously driven milling belt 17 and pressed by it against the support plate 18, which is located above the end of the horizontal milling belt 17. The straw bale 15 is broken up by the milling edges 21 of the milling belt 17, and the broken up and loosened straw 22 falls from the end of the milling belt 17 into the receiving hopper 19. The receiving hopper 19 then leads into the discharge screw conveyor 20, which conveys the straw 22 out of the housing 16 and into the conveying channel 3.

[0017] Preferably, grains and other fine particles that arise when the straw bale 15 is broken up are also extracted from the housing 16.

[0018] As already explained, the straw 22 is conveyed into the conveying channel 3 and through this channel to the weighing device 4. Preferably, the conveying is carried out solely by the conveying pressure generated by the discharge auger 20.

[0019] At the end facing the weighing device, the conveying channel 3 preferably has a sensor 23 for detecting or measuring the conveying pressure. Furthermore, the conveying channel 3 has a milling roller 24 and a deflection hood 25 at the end facing the weighing device.

[0020] The detection of the conveying pressure serves to maintain a constant conveying rate. If deviations from the target conveying pressure are detected, the straw bale disassembly unit 2 is controlled to supply more or less straw 22. The straw bale disassembly unit 2 is therefore controlled, among other things, based on the conveying pressure measured by sensor 23.

[0021] The milling roller 24 conveys the straw 22 in portions into the weighing device 4. For this purpose, the milling roller 24 has milling edges 24a in a manner known per se. These milling edges 24a divide individual portions of straw from the straw bale, with each portion being picked up between two adjacent milling edges 24a and conveyed into the weighing device 4. The straw 22 is deflected or guided by the deflecting hood 25 such that it falls into the weighing device 4.

[0022] The weighing device 4 ( Fig. 1 , 2 , 4 , 5 ) has a U-shaped trough 26 with a first and a second trough end 26a;b, a frame 27 and a snowplow blade 28. The frame 27 is placed on the ground and the trough 26 is suspended from the frame 27 by means of four load cells 29 which are connected to the control device 11.

[0023] The straw 22 is now conveyed in portions into the trough 26 by means of the milling roller 24 and weighed there. The vertical clearing blade 28 is arranged at the first end 26a of the trough, facing the milling roller 24, and closes off the trough 26.

[0024] In particular, straw 22 is conveyed into the trough 26 in portions until the desired quantity of straw 22 is reached. This is preferably between 2.0 and 10.0 kg, more preferably between 2.1 and 4.2 kg.

[0025] Once the desired quantity of straw has been reached, the milling roller 24 is stopped and the weighed portion of straw is pushed out of the trough 26 by means of the clearing blade 28. For this purpose, the clearing blade 28 is moved from the first end of the trough 26 to the second end 26b, thereby pushing the straw 22 out of the trough 26 at the second end 26a and conveying it into the vibrating trough 5.

[0026] The vibrating trough 5 ( Fig. 1 , 2 , 6The vibrating trough 5 has a U-shaped trough wall 30, which is attached to the ground by means of throw arms 31. Furthermore, the vibrating trough 5 has a first, lower trough end 5a, facing the weighing device 4, and a second, upper trough end 5b. The vibrating trough 5 is therefore preferably not horizontal, but inclined. It conveys the straw 22 from bottom to top, from the lower trough end 5a to the upper trough end 5b.

[0027] To achieve the vibrating or rocking motion of the channel wall 30, the channel wall 30 is attached to the ground by means of the throw arms 31. For this purpose, the throw arms 31 are rotatably attached to the ground at one end about a horizontal axis and rotatably attached to the channel wall 30 at the other end about a horizontal axis. In addition, the vibrating channel 5 has at least one drive arm 32, preferably two drive arms 32 on each side. The drive arm 32 is attached at one end to the channel wall 30 and at the other end eccentrically to a drive disc 33, which in turn is rotatably connected to a drive motor.

[0028] The straw 22 is conveyed in a manner known per se by the shaking or rocking motion of the vibrating trough 5. This causes the straw 22 to be thrown forward at regular intervals in a trough conveying direction 5b and simultaneously homogenized. This homogenization is important to achieve a constant mass flow of the straw 22, which was previously portioned during weighing. Consequently, the vibrating trough 5 serves to convey the straw 22 and to homogenize the mass flow of the straw 22. For this reason, it is operated continuously.

[0029] According to an advantageous aspect of the invention, calcium hydroxide dust is now added to the straw 22 at the upper end of the trough 5b. For this purpose, the calcium hydroxide feed device 6 is arranged at the upper end of the trough 5b above the trough wall 30.

[0030] Furthermore, the channel wall 30 has a drop-off edge 34 at the upper channel end 5, from which the straw 22 falls. Preferably, the channel bottom 30a of the channel wall 30 has a downward slope at the upper channel end 5b, so that the straw 22 falls out of the channel wall 30 more easily.

[0031] The trough floor 30a also preferably has a non-slip, preferably sandy, surface on the inside, in order to be able to transport the light and smooth straw 22 by the throwing motion.

[0032] The straw 22 falls from the channel wall 30 into a collecting funnel 35 of a radial blower 36, which is located at the beginning of the further conveying channel 7.

[0033] The calcium hydroxide feed device 6, as already explained, serves to dose very fine, powdery calcium hydroxide (Ca(OH)₂). In particular, the calcium hydroxide has a particle size of ≤ 100 µm, preferably ≤ 90 µm, according to DIN EN 459-1:2015-07. The calcium hydroxide is used to adjust certain properties of the straw insulation boards 12 to be manufactured.

[0034] Among other things, the pH value and color of the straw insulation boards 12 can be influenced. Additionally, the hydrated lime enhances the binding properties of the binder and affects the surface hardness of the straw insulation boards 12.

[0035] This requires very precise dosing of the hydrated lime.

[0036] A problem with dosing is that the very fine calcium hydroxide is highly prone to clumping and bridging when slightly compacted. Consequently, the calcium hydroxide feeding device 6 preferably has a special embodiment:

[0037] The calcium hydroxide feed unit 6 ( Fig. 1 , 2 , 7 , 8 , 9 ) has a storage container 37 for receiving the hydrated lime, a drive motor 38, a mixer shaft 39 with mixer rods 40, and a rotary valve 41 with a blow-out mechanism or a blow-out device 46.

[0038] The storage container 37 is preferably funnel-shaped, tapering downwards and open at the top. It also has a container wall 37a and a container interior 37b.

[0039] The mixer shaft 39 extends horizontally through the interior of the container 37b. It is also rotatably mounted at both ends in the container wall 37a about its horizontal axis of rotation 39a. Furthermore, the mixer shaft 39 is rotatably connected to the drive motor 38 about its axis of rotation 39a. The mixing rods 40 extend radially away from the mixer shaft 39 with respect to the axis of rotation 39a.

[0040] The mixer shaft 39 with the mixer rods 40 is arranged above the rotary valve 42. It serves to loosen the hydrated lime located in the storage container 37 and improves the trickling of the hydrated lime onto the rotary valve 42.

[0041] The drive motor 38 is preferably a stepper motor. The stepper motor ensures a precise rotational speed and thus precise dosing of the hydrated lime. However, it could also be a servo motor. Furthermore, it could be a DC motor or an AC motor. The drive motor 38 is preferably mounted externally on the storage container 37.

[0042] The rotary valve 41 is, as already explained, arranged below the mixer shaft 39. It has a rotating rotary valve 42, a valve housing 43, a valve inlet 41a and a valve outlet 41b. The valve inlet 41a is arranged vertically aligned below the mixer shaft 39.

[0043] In particular, the lock housing 43 is part of the container wall 37a.

[0044] The rotary valve 42 has a rotary valve axis 42a and several circumferentially adjacent cells 44 for receiving the calcium hydroxide. The cells 44 are groove-shaped and extend longitudinally parallel to the rotary valve axis 42a. The cells 44 extend radially into the rotary valve 42 with respect to the rotary valve axis 42a.

[0045] Furthermore, the cell wall of the cells 44 preferably has a circular arc-shaped, more preferably semicircular, cross-section. In particular, the cross-section extends over a maximum of 180° or a semicircle. This facilitates the falling out of the powdery calcium hydroxide from the cells 44. In particular, the falling out is facilitated compared to cells with a rectangular, especially triangular, cross-section.

[0046] Preferably, the cells 44 each have a volume of 300 mm³ to 3000 mm³, preferably 400 mm³ to 800 mm³.

[0047] The rotary valve 42 preferably has a delivery rate of 10,000 mm³ / min to 500,000 mm³ / min, preferably 30,000 mm³ / min to 50,000 mm³ / min.

[0048] Furthermore, the rotary valve 42 is rotatably connected to the drive motor 38 about the rotary valve axis 42a. Preferably, the rotary valve 42 and the mixer shaft 39 are coupled to each other via a belt drive, gear drive, direct drive by a second motor, or the like. The rotary valve 42 and the mixer shaft 39 are thus synchronized, preferably mechanically and / or electronically. Consequently, the rotary valve 42 is preferably rotatably connected to the drive motor 38 about the rotary valve axis 42a via the mixer shaft 39.

[0049] The rotary valve 42 is also rotatably mounted in the lock housing 43 about the rotary valve axis 42a in a manner known per se.

[0050] Each cell 44 receives hydrated lime below the sluice inlet 41a in a manner known per se, and the hydrated lime is conveyed out of the cell 44 at the sluice outlet 41b. According to a particularly advantageous aspect of the invention, the hydrated lime is blown out of the cell 44 at the sluice outlet 41b by means of compressed air.

[0051] As already explained, the rotary valve 41 has the blow-out device 46 for this purpose.

[0052] The blow-off device 46 has a compressed air source 47, which preferably provides a constant supply of compressed air. Furthermore, the lock housing 43 has a blow-off channel 45 in the area of ​​the lock outlet 41b. The blow-off channel 45 has an inlet end 45a and an outlet end 45b, both of which open to the environment. The blow-off channel 45 is preferably U-shaped. The compressed air source 47 is connected to the inlet end 45a, for example by means of a hose 48.

[0053] Furthermore, the discharge channel 45 extends below the rotor 42 and parallel to the rotor's axis of rotation 42a from one end of the rotor 42 to the other. The discharge channel 45 is open towards the rotor 42. This ensures that the discharge channel 45 is connected to the cell 44, which is located in the lowest position.

[0054] As already explained, the compressed air source 47 preferably provides a constant supply of compressed air. This results in a constant flow of compressed air from the duct inlet end 45a to the duct outlet end 45b through the discharge duct 45.

[0055] As soon as a cell 44 has rotated downwards far enough to connect with the discharge duct 45, the compressed air is blown not only through the discharge duct 45 but also through the cell 44 connected to it. This blows the calcium hydroxide contained in cell 44 out of the cell 44. The air / calcium hydroxide mixture is then blown into the environment at the duct outlet 45b or exits from the airlock housing 43 and the calcium hydroxide feed device 6. It exits in the form of a calcium hydroxide aerosol. This means that the calcium hydroxide particles are very finely dispersed in the air.

[0056] The blow-off device 46 serves to reliably remove the calcium hydroxide from the cells 44. The constant airflow also completely removes any lime dust adhering to the cells 44 and ensures a homogeneous distribution of the calcium hydroxide into the straw 22. In the blow-off channel 45, the air vortices generated by the compressed air further break up small lumps of calcium hydroxide, which are then discharged in powder form and evenly in the airflow. The formation of these air vortices is facilitated, among other things, by the U-shape of the blow-off channel 45.

[0057] As already explained, the lime hydrate feed device 6 is arranged at the upper end of the trough 5b above the trough wall 30. In particular, the channel outlet 45b is arranged above the trough wall 30 in such a way that the air / lime hydrate mixture exiting the channel outlet 45b is fed to the straw 22 located in the vibrating trough 5 shortly before it falls from the discharge edge 34.

[0058] Preferably, the vibrating trough 5 also has a perforated plate 49 as a cover at the upper end of the trough 5b, so that the straw 22 does not escape upwards.

[0059] The calcium hydrate feeding device 6 thus enables a very precise, portion-wise and homogeneous addition of calcium hydrate to the straw 22 in very small quantities.

[0060] As already explained, the straw 22 mixed with the hydrated lime falls from the channel wall 30 into the collection hopper 35 of the radial blower 36, which is located at the beginning of the further conveying channel 7. By means of the airflow generated by the radial blower 36, both the hydrated lime is drawn in and the straw 22 is conveyed through the further conveying channel 7 via the cyclone separator 50 to the mixing unit 8.

[0061] An advantage of the radial blower 36 is that it can cut longer stalks. Preferably, the straw 22 after passing through the radial blower 36 has a maximum stalk length of ≤ 10 cm, more preferably a stalk length of 5 to 7 cm.

[0062] The cyclone separator 50 has, in a manner known per se, a cyclone inlet 50a, an upper air outlet 50b, and a lower material outlet 50c. Preferably, the cyclone separator 50 is a tangential separator.

[0063] Furthermore, the cyclone separator 50 has a cyclone wall 53, which has a conical section in a manner known per se, and a dip tube 54.

[0064] Furthermore, the cyclone separator 50 can have one or more addition points 64 at which further dry or liquid components can be added to the straw 22. In particular, the components are injected. For example, the components can be preservatives, especially sodium lauryl sulfate, or other additives, especially hydrating agents.

[0065] At the cyclone inlet 50a, the straw 22 mixed with the hydrated lime, along with the conveying air, is blown tangentially into the cyclone separator 50. Within the cyclone separator 50, the separation between the air and the straw 22 then takes place in a manner known per se. Due to the conical narrowing, the rotational speed of the straw 22 increases to such an extent that centrifugal force throws the straw 22 against the inner cyclone wall 53, slowing it down sufficiently to detach it from the flow and trickle downwards to the material outlet 50c. The air exits the cyclone separator 50 through the dip tube 54.

[0066] A mixer rotary valve 52 is arranged at the material outlet 50c. This serves to convey the straw 22 from the cyclone separator 50 into the mixing unit 8.

[0067] The mixer rotary valve 52 comprises a valve housing 55, a rotary valve 56 arranged therein, and a drive motor (not shown) for the rotary valve 56. The rotary valve 56 is rotatably connected to the drive motor about a rotary axis, preferably horizontal, preferably at a speed of 200 to 950 rpm, more preferably 350 to 500 rpm. The relatively high rotational speed ensures that the straw 22 does not clog the rotary valve 56, as straw is generally less free-flowing than other bulk materials.

[0068] The mixing device 8 ( Fig. 1 , 2 , 10 , 11 ) has a multi-level mixer 51 according to the invention.

[0069] The multi-level mixer 51 has an upper mixer inlet 51a and a lower mixer outlet 51b, and several, preferably 3 to 10, preferably 4 to 5, mixing chambers 51c arranged one above the other. The multi-level mixer 51 also has a mixer wall 57, in particular a hollow cylindrical one, a rotating or rotatably driven mixer shaft 58, a drive motor 100 for the mixer shaft 58, several fixed intermediate floor sections 59, several movable intermediate floor sections 60, a binder addition device 61, and several mixer forks 62. Each mixing chamber 51c in the multi-level mixer 51 has one fixed intermediate floor section 59 and two movable intermediate floor sections 60, as well as at least one mixer fork 62, preferably two to four mixer forks 62, per level.

[0070] Furthermore, the multi-level mixer 51 preferably has a mixer support frame 101.

[0071] The mixer wall 57 surrounds a mixer interior or mixing chamber 57a. Preferably, the mixer wall 57 is also mounted on the mixer support frame 101. Furthermore, the mixer wall 57 is preferably formed from several, strip-shaped wall segments 57b arranged side by side in the circumferential direction. This increases the stability of the mixer wall 57.

[0072] Preferably, the mixer wall 57 also has a door 102.

[0073] The binder addition device 61 serves to add a thermosetting binder mixture to the straw 22. For this purpose, the binder addition device 61 is preferably arranged in the uppermost mixing chamber 51c, preferably above the solid intermediate floor part 59.

[0074] Preferably, the binder mixture is added in liquid form. The binder addition device 61 also preferably has a nozzle for injecting the binder mixture into the mixer interior 57a.

[0075] The liquid binder mixture preferably contains water as a carrier substance.

[0076] Furthermore, the binder mixture preferably contains at least one protein and / or starch. This protein can be of animal or plant origin. The binder mixture may also contain additives and / or admixtures.

[0077] The mixer shaft 58 is arranged within the mixer wall 57. It has a vertical axis of rotation 58a. Furthermore, the mixer shaft 58 is rotatably connected to the drive motor 100 about the axis of rotation 58a. The drive motor 100 is preferably an asynchronous motor, particularly with a bevel gear or worm gear. For space reasons, the drive motor 100 is preferably arranged above the mixer wall 57. This also spatially separates the drive motor 100 from the exiting mixture and protects it from damage caused by dust and aerosols.

[0078] The mixer forks 62 each have a stem 65 and at least two protruding tines 66. The stem 65 is fixedly attached at one end to the mixer shaft 58 and extends radially from it in the direction of the mixer shaft's axis of rotation 58a. The tines 66 are attached to the other end of the stem 65. The tines 66 of a mixer fork 62 are preferably arranged vertically one above the other and aligned with each other.

[0079] Furthermore, the tines 66 are mounted on the stem 65 so as to be deflectable about a vertical tine rotation axis 66a. In a non-deflection position, the tines 66 extend radially in relation to the mixer shaft rotation axis 58a. They are thus arranged in line with the stem 65. From the non-deflection position, the tines 66 can be deflected on both sides, or in two directions, against the force of at least one spring 67. In the deflected position, the at least one spring 67 thus exerts a restoring force on the tines 66 to their non-deflection initial position.

[0080] Alternatively, the mixer forks 62 do not have a handle 65, but the two tines 66 are connected to each other via the spring 67. The spring 67 is fixedly attached to the mixer shaft 58. In this case as well, the tines 66 can be deflected on both sides or in two directions against the force of the spring 67.

[0081] The spring-loaded tines 66 prevent material build-up. This is because it was found during the invention process that the straw 22, when coated with the binder mixture, tends to clump. In the worst case, this can lead to blockages and obstructions of the mixing system. The spring-loaded tines 66 effectively break up material build-up and prevent force peaks that could damage the system, as the tines 66 can deflect.

[0082] The fixed, horizontal intermediate floor sections 59 are preferably arranged adjacent to each other in the vertical direction and aligned with each other. Furthermore, the fixed, horizontal intermediate floor sections 59 have a crescent shape. In particular, the fixed intermediate floor sections 59, with their convex, arcuate base wall 59a, are connected to or adjoin the mixer wall 57 on the inside. A concave, also arcuate base wall 59b is arranged at a distance from the mixer shaft 58. The fixed intermediate floor sections 59 are thus rigidly connected to the mixer wall 57.

[0083] Preferably the fixed, horizontal intermediate floor parts 59 are also made of metal, preferably of steel, preferably of stainless steel.

[0084] The movable, horizontal intermediate floor sections 60 are also preferably arranged adjacent to each other in the vertical direction. They are also arranged in pairs.

[0085] Furthermore, the movable, horizontal intermediate floor sections 60 each have a convex, circular arc wall 60a, a straight circumferential wall 60b, and a convex, arc-shaped outer circumferential wall 60c. The diameter of the convex, circular arc wall 60a corresponds to the diameter of the concave, circular arc wall 59b of the fixed intermediate floor sections 59. The straight circumferential wall 60b also has a recess 103 for receiving a mixer shaft.

[0086] Preferably the movable intermediate floor parts 60 are also made of metal, preferably of steel, preferably of stainless steel.

[0087] In one respect, the movable, horizontal intermediate floor parts 60 can also be extended into and out of the mixer interior 57a, preferably in a direction perpendicular to the mixer shaft rotation axis 58a.

[0088] For this purpose, the movable, horizontal intermediate shelf sections 60 are each rotatably mounted about a vertical intermediate shelf pivot axis or hinged to bearing elements 104 of the mixer support frame 101. They also each extend through a slot in the mixer wall 57. Furthermore, the movable, horizontal intermediate shelf sections 60 are each connected to a pneumatic cylinder 105, allowing them to rotate back and forth about the intermediate shelf pivot axis. The pneumatic cylinders 105 are preferably supported at one end by the mixer support frame 101 and at the other end by the respective movable intermediate shelf section 60, in particular by its outer circumferential wall 60c.

[0089] The two movable intermediate floor sections 60 of a mixing chamber 51c are moved towards each other and away from each other in a scissor-like manner when moving in and out.

[0090] In a retracted position, the movable, horizontal intermediate floor sections 60 are also arranged in a vertical direction aligned with each other.

[0091] Furthermore, the two movable intermediate floor sections 60 of a mixing chamber 51c are each arranged horizontally adjacent to and aligned with a fixed intermediate floor section 59. In particular, the intermediate floor sections 59 and 60 are arranged such that they each form a continuous, horizontal intermediate floor 63 when the two movable intermediate floor sections 60 are in their retracted position.

[0092] In particular, the convex, arc-shaped base walls 60a of the two movable intermediate floor sections 60 are positively engaged with the concave, arc-shaped base wall 59b of the fixed intermediate floor section 59. Furthermore, the two straight base walls 60b of the two movable intermediate floor sections 60 are also in contact with each other. And the mixer shaft 39 is arranged within the two mixer shaft receiving recesses 103.

[0093] This ensures that the straw 22 located on the intermediate floor 63 remains on the intermediate floor 63 in the respective mixing chamber 51c and is mixed by means of at least one mixing fork 62, preferably with two to four mixing forks 62.

[0094] The intermediate shelves 63 separate each of the individual mixing chambers 51c from one another.

[0095] After the straw 22 has been mixed in a mixing chamber 51c for a specific time, in particular for 30 to 120 s, preferably 35 to 60 s, the two movable intermediate floor sections 60 are moved out of the mixer interior 57a. This causes the straw 22 to fall onto the intermediate floor 63 of the mixing chamber 51c below. This process is repeated until the straw 22 reaches the mixer outlet 51b. At the mixer outlet 51b, the mixed straw 22 then falls out of the multi-level mixer 51 and, in particular, into a further conveying channel 9, through which the straw 22 is transported to the insulation board pressing device 10.

[0096] Furthermore, the opening and closing processes preferably each last 2 to 4 s and the movable intermediate shelves 60 preferably remain in their open position for 8 to 12 s.

[0097] As previously explained, it was found within the scope of the invention that the straw 22, when moistened with a binder mixture, tends to clump and become clogged during mixing. The advantage of the multi-level mixer 51 is that the mass flow of the straw 22 is divided by the mixing chambers 51c. Nevertheless, the mixing process is essentially continuous. The mixing chamber is divided into individual, stacked mixing chambers 51c. The conveyance of the straw 22 is regulated by means of the movable intermediate floor sections 60, by adjusting the opening times of these sections. This prevents the individual mixing chambers 51c from becoming overfilled. This forced division of the mass flow, and the equally enforced residence time of the mixture in the individual mixing chambers 51c, results in a high mixing quality.

[0098] As already explained, mixed straw 22 is conveyed through the conveying channel 9 to the insulation board pressing device 10.

[0099] The insulation board pressing device 10 ( Fig. 1 , 14-16 The continuous insulation board pressing device 10 preferably comprises a throwing device 68, a conveyor belt 69, a compaction and binder activation device 70, a drying device 72, and a cutting device 73. Furthermore, the continuous insulation board pressing device 10 preferably comprises a base frame 74.

[0100] The throwing device 68 serves to throw or hurl the straw 22 arriving from the conveying channel 9 onto the conveyor belt 69. For this purpose, a channel outlet of the conveying channel 9 is arranged above the throwing device 68, so that the straw 22 falls from the conveying channel 9 into the throwing device 68.

[0101] The throwing device 68 ( Figs. 15-17 ) has a collection container 75, a bucket 76 rotating about a bucket rotation axis 76a and a drive motor 77 for driving the bucket 76.

[0102] The collection container 75 is mounted on the base frame 74. Furthermore, the collection container 75 has a curved container wall 78a and two adjoining container side walls 78b. The two container side walls 78b are arranged opposite each other when viewed in the direction of the blade rotation axis 76a. The curved container wall 78a is preferably rotationally symmetrical to the blade rotation axis 76a. The curved container wall 78a is thus designed as a cylindrical shell section. The collection container 75 is open at the top and has a container opening 75a. The collection container 75 is thus designed as a collection tray. The two container side walls 78b and the curved container wall 78a enclose a container interior 75b.

[0103] Preferably, the throwing device 68 also has two protective plates 79, each of which connects to an end edge of the curved container wall 78a and projects outwards from it. The protective plates 79 serve in particular to prevent straw from falling into the drive motor 77.

[0104] The blade 76 has a blade shaft 80, preferably hollow cylindrical, and a single blade 81. However, several blades 81 are also possible, although a single blade is preferred. The blade shaft 80 is rotationally symmetrical about the blade rotation axis 76a. The blade 81 projects radially away from the blade shaft 80 with respect to the blade rotation axis 76a.

[0105] The bucket 76 is rotatably mounted in the area of ​​the container opening 75a by means of the bucket shaft 80 about the bucket axis of rotation 76a. Furthermore, the bucket 76 is rotatably connected to the drive motor 77 about the bucket axis of rotation 76a, e.g., via a belt drive (not shown). The drive motor 77 is preferably a three-phase motor (asynchronous motor) and / or a servo motor.

[0106] During rotation, the shovel 76 rotates partly inside the collection container 75 and partly outside of it. It is dimensioned such that it is slightly spaced from the curved container wall 78a and the two container side walls 78b. The shovel 76 thus removes the straw 22 located inside the container 75b.

[0107] The conveyor belt 69 moves in a horizontal conveying direction 82. The conveying direction 82 is perpendicular to the blade rotation axis 76a.

[0108] The conveyor belt 69 is mounted on the base frame 74. Furthermore, side walls 83, particularly vertical ones, are present on both sides of the conveyor belt 69. These are also mounted on the base frame 74. The two side walls are positioned opposite each other in a direction parallel to the blade rotation axis 76a. They also extend to the throwing device 68 and shield it laterally.

[0109] As previously explained, the straw 22 falls from the conveying channel 9 into the throwing device 68. Specifically, it falls into the collection container 75 and onto the rotating paddle 81. This causes the straw 22 to be captured by the paddle 81 and thrown in a parabolic trajectory onto the conveyor belt 69. There, it settles according to a Gaussian normal distribution. This results in a uniformly thick, continuous, or endless layer of straw on the conveyor belt 69. This homogenization process ensures a uniform density distribution of the straw layer in the conveying direction 82 and transforms the individual straw portions coming from the mixing device 8 into a uniform mass flow.

[0110] The constant density distribution perpendicular to the conveying direction 82 is achieved in particular via the two side walls 83. The straw stalks, which would otherwise be deposited in the outer edge region, are collected by the side walls 83 and "added" to the flatter edge region of the mixture, so that a homogeneous density distribution is also achieved across the cross-section.

[0111] The continuous layer of straw located on conveyor belt 69 is then transported by means of conveyor belt 69 into the compaction and activation device 70.

[0112] The compaction and activation device 70 has a continuously driven press belt 85, which is arranged above the conveyor belt 69. Viewed in the conveying direction 82, the distance between the press belt 85 and the conveyor belt 69 initially decreases and then remains constant. A funnel, tapering in the conveying direction 82, is thus formed between the press belt 85 and the conveyor belt 69, in which the straw layer is increasingly compacted into an endless strand or sheet of straw. Furthermore, the straw layer is drawn into the funnel by the conveyor belt 69 and the press belt 85.

[0113] After the straw layer has been compacted to the desired thickness, the binder mixture is thermally activated. For this purpose, the straw strand is exposed to steam. Preferably, the steam is applied alternately from above and from the top in the conveying direction 82. If necessary, a vacuum is also applied from the vertically opposite side, so that the steam is drawn through the straw strand. This ensures homogeneous steam application to the straw strand and uniform thermal activation of the binder mixture across the entire cross-section of the straw strand.

[0114] The conveyor belt 69 and the press belt 85 are also preferably designed as perforated belts so that the steam can flow through the belts 69;85 into the straw strand.

[0115] Furthermore, the conveyor belt 69 and the press belt 85 are preferably made of plastic, preferably polypropylene. This prevents the binder mixture from adhering to the respective belt 69; 85. However, the conveyor belt 69 and the press belt 85 can also be made of stainless steel and be designed as perforated belts. This is advantageous for higher panel densities.

[0116] After the compaction and activation unit 70, the compacted straw strand is conveyed to the drying unit 72 by means of the conveyor belt 69.

[0117] Drying is particularly advantageous because the straw strand is relatively moist due to the condensed water vapor, which activates the binding agent. This results in lower strength and binding capacity of the binder. To achieve sufficient strength for further processing, especially cutting, within a reasonable timeframe, the straw strand is dried.

[0118] The drying device 72 is preferably designed as a drying channel for this purpose.

[0119] In the drying unit 72, the straw strand is alternately exposed to hot air for drying in the conveying direction 82, preferably first from above, then from below, and then again from above. This ensures uniform drying across the cross-section of the straw strand. Preferably, the supplied hot air has a temperature of 100 to 120 °C, more preferably 105 to 115 °C.

[0120] On the opposite side, the hot air is preferably extracted to further improve the flow of hot air through the straw strand in a vertical direction.

[0121] The drying device 72 also preferably has several circumferentially driven drive belts 86 arranged above the conveyor belt 69, which ensure uniform transport of the straw strand and keep it in shape.

[0122] After the drying unit 72, the dried straw strand is conveyed to the cutting unit 73 by means of the conveyor belt 69.

[0123] The cutting device 73 serves to cut the endless straw strand into individual straw insulation panels 12. For this purpose, the cutting device 73 preferably has a traveling circular saw 87 or a traveling band saw.

[0124] As already explained, the manufactured straw insulation panels 12 have a low density and therefore good thermal insulation properties.

[0125] Preferably the straw insulation panels 12 have a thermal conductivity λ D of 0.038 to 0.049 W / m·K, preferably of 0.039 to 0.045 W / m·K, according to DIN EN 13171:2015-04, section 4.2.1.

[0126] Furthermore, the straw insulation panels 12 preferably have a bulk density of 100 to 150 kg / m 3< , preferably, 105 to 120 kg / m 3< , according to DIN EN 1602:2013-05.

[0127] Preferably the straw insulation boards 12 are used as plaster base boards or load distribution boards or impact sound insulation boards or simply for thermal insulation, in particular in a thermal insulation composite system.

[0128] According to a further embodiment of the invention, the device 1 according to the invention serves ( Fig. 2 , 18 , 19 ) for the production of dense straw boards 13.

[0129] The device 1 according to the further embodiment differs from the device 1 according to the first embodiment only in that the plate pressing device 14 is designed differently, since a higher compaction is necessary.

[0130] In addition, a small amount of binder mixture is preferably added.

[0131] The press device 14 has, in the conveying direction 82, a receiving device 87, a press 88 and preferably a trimming device 89 arranged one after the other.

[0132] The receiving device 87 has a driveable receiving conveyor belt 90, two boundary walls 91 spaced apart from each other in a horizontal direction and a distribution device 92.

[0133] The boundary walls 91 are adjacent to each other in a direction perpendicular to the conveying direction 82 and are arranged on both sides of the receiving conveyor belt 90. They thus laterally delimit the receiving conveyor belt 90.

[0134] The straw 22, coming from the mixing unit 8 and mixed with the binder mixture, is now applied to the receiving conveyor belt 90. This is done, for example, by arranging the receiving conveyor belt 90 directly below the mixing unit 8 and allowing the straw 22 to fall directly from the mixing unit 8 onto the receiving conveyor belt 90.

[0135] Alternatively, the straw 22 can also be applied to the receiving conveyor belt 90 in another way, e.g. by means of a conveying device, e.g. a conveyor belt or a conveying channel.

[0136] Figure 19 This shows preferred further conveying options. Accordingly, the device 1 has, downstream of the mixing unit 8, a further vibrating trough 84, a radial blower 93 adjoining it, a conveying channel 97 adjoining it, and a cyclone separator 98 adjoining it, which preferably has a rotary valve 99 at its lower end. The vibrating trough 84 is designed in a manner analogous to the first vibrating trough 5. The radial blower 93 and the conveying channel 97 have the advantage that the mixing quality is maintained by the conveying process of the air conveying.

[0137] The cyclone separator 98 serves to separate the conveying air. Preferably, the straw 22 is also applied by the cyclone separator 98 in a meandering pattern, preferably in a cross pattern, onto the receiving conveyor belt 90. For this purpose, the cyclone separator 98 is preferably movable on a portal in two mutually perpendicular horizontal directions, one direction being parallel to the conveying direction 82. Alternatively, the cyclone separator 98 can also be movable only perpendicular to the conveying direction 82, and the receiving conveyor belt 90 moves in the conveying direction 82 when the straw 22 is applied.

[0138] By means of the distribution device 92, the straw 22 is then evenly distributed on the receiving conveyor belt 90 to form a straw cake 71. Preferably, the distribution device 92 has a portal with distribution arms that can be moved back and forth in two mutually perpendicular, horizontal directions.

[0139] Once the straw 22 is evenly distributed, the receiving conveyor belt 90 is driven and the straw cake 71 is conveyed into the press 88 in the conveying direction 82 by means of the receiving conveyor belt 90.

[0140] The press 88 has a lower, circumferential press belt, preferably with a separating film, as well as two superimposed, heated press plates 94 and preferably a separating film arranged between the upper press plate 94 and the straw cake 71. The press belt runs around the lower press plate 94. The press belt serves, firstly, to convey the straw cake 71 into the press 88, for which purpose it is driven until the straw cake 71 has reached its predetermined position between the two press plates 94.

[0141] To compress the straw cake 71, the two parallel press plates 94 are pressed together, preferably hydraulically. To achieve a defined distance and thus a defined thickness of the straw slab 13 to be produced, the two press surfaces 94a of the two press plates 94 are preferably kept apart by spacer strips at the edge of the press surfaces 94a.

[0142] During pressing, the press belt is not driven and is positioned between the straw cake 71 and the lower pressing surface 94a. It thus forms a temperature-stable separating layer between the straw cake 71, especially the binder, and the lower heated press plate 94.

[0143] After pressing, the press belt also serves to convey the straw slab 13 out of the press 88 in the conveying direction 82 into the edging device 89.

[0144] In the edging device 89, the edges of the straw board 13 are edged, preferably by means of a reciprocating circular saw 95. The edging device 89 also preferably has an edging device conveyor belt 96 for conveying the straw board 13.

[0145] The produced straw slabs 13 are then removed from the edging device 89.

[0146] In the second embodiment of the device 1 according to the invention, the heat for activating the binder is primarily introduced into the straw layer via the pressing surfaces 94a, which are preferably heated by means of thermal oil. The pressing surfaces 94a preferably have a temperature of 100 to 120 °C, more preferably 105 to 115 °C.

[0147] However, even at higher compression, heat conduction into the interior of the straw cake 71 is not optimal. It is assumed, however, that water vapor forms from the water content of the binder mixture, which is forced into the boards by the increased vapor pressure in the quasi-tight pressing environment. This likely results in the same heat transfer mechanism, through vapor condensation, as previously described in the production of the straw insulation boards 12.

[0148] Due to the high temperature, the introduction of heat through contact, and the lower binder content, the manufactured straw panels 13 achieve very good surface strength and dimensional stability upon exiting the press 88. Unlike the straw insulation panels 12, which are typically dried afterward to maintain their shape, these panels do not require post-drying. The residual moisture content essentially equalizes with the ambient humidity within one day.

[0149] The invention also includes the production of straw insulation panels 12 using the device 1, which has the pressing device 14.

[0150] Figure 20 Figure 1 shows a device 1 according to the most preferred embodiment of the invention. The device 1 according to the most preferred embodiment of the invention also serves to produce dense straw panels 13 or straw insulation panels 12.

[0151] The device 1 comprises, in a sequence, the straw bale dissolving device 2, the conveying channel 3, a homogenizing screw 106, a stone separator 107, a straw shredder 108, a radial blower 109, a conveying section 110, preferably a conveying channel, a cyclone separator 111, a weighing device 112, a screw mixer 113 according to the invention, a binder addition device 114, a radial blower 115, a conveying section 116, preferably a conveying channel, preferably the distribution device 92, as well as the pressing device 14 and the control device 11.

[0152] If the device 1 is used exclusively for the production of straw insulation boards 12, it has the insulation board pressing device 10 instead of the pressing device 14 (not shown).

[0153] The homogenization screw 106 ( Fig. 20) connects to the conveying channel 3. In contrast to the other two embodiments, the conveying channel does not have a milling roller 24.

[0154] The homogenizing screw 106 comprises a collection container 118 and a homogenizing conveying screw 119. The straw is conveyed into the collection container 118 by the discharge conveying screw 20 of the straw bale dismantling device 2. The collection container 118 preferably has mechanical level sensors that detect the fill level. The conveying capacity of the straw bale dismantling device 2 is preferably controlled by the control unit 11 based on the signals from the level sensors.

[0155] The homogenizing screw 106 ensures a uniform and well-aerated straw flow. The homogenizing conveying screw 119 draws a homogeneous mass flow of straw from the collection container 118 and conveys the straw 22 into the stone separator 107.

[0156] The stone separator 107 ( Fig. 20 The device is preferably a riser pipe classifier. The stone separator 107 preferably has an upright, preferably vertical, separator tube 120, which is open at the bottom and suspended. The separator tube 120 also has a lateral opening 120a at the bottom, into which the straw 22 is fed by the homogenizing screw conveyor 119. A lower opening 120b of the separator tube 120 is suspended above and spaced apart from a cone 121, the cone 121 and the separator tube 120 being coaxial with each other. An air gap is present between the cone 121 and the separator tube 120.

[0157] The conveying air required for transporting the straw 22 through the stone separator 107 is drawn in by the blower 115 located downstream of the stone separator 107. The size of the air gap allows both the volume and flow velocity of the conveying air to be adjusted. The conveying air carries the conveyed straw 22 upwards. Other particles, which have a different mass or density than the straw, cannot be transported upwards against gravity by the conveying airflow and fall downwards out of the separator pipe 120.

[0158] By means of the stone separator 107, the straw 22 can thus be separated from heavier particles, e.g. stones and / or dirt and / or grains and / or metal, in a simple and reliable manner. This protects the individual components of the device 1 according to the invention in the further manufacturing process and improves the quality of the panels 12;13 to be produced.

[0159] The stone separator 107 can of course also be present in a particularly advantageous way in the devices 1 described above.

[0160] As already explained, the straw 22 is fed from the stone separator 107 into the straw chopper 108. The straw chopper 108 is known per se and serves to chop the straw stalks to a predetermined length, preferably to a length of 10 mm to 60 mm, more preferably 20 mm to 40 mm. For this purpose, the straw chopper has rotating blades in a manner known per se. At least some of the straw stalks of the straw 22 are also split.

[0161] The Straw Witch 108 process makes the straw 22 more homogeneous and a more precisely defined raw material. This improves the quality of the boards, regardless of the quality of the delivered straw cuttings. The cut straw 22 also exhibits better airflow and mixability, as it becomes more free-flowing.

[0162] A further advantage is that the adhesion of the binding agent to the straws is improved, since splitting the straws allows the inner surfaces to also be wetted. The wettable surface area is thus increased.

[0163] The increased number of contact points during bonding also improves the plate statics.

[0164] Furthermore, the plates 12;13 have a more homogeneous appearance and further processing, in particular sawing and / or milling, is facilitated.

[0165] The straw witch 108 can of course also be present in a particularly advantageous way in the devices 1 described above.

[0166] The shredded straw 22 is conveyed from the straw shredder 108 to the cyclone separator 111 via the conveyor 116. The cyclone separator 111 serves to separate the conveying air from the straw 22 and to fill the weighing device 112.

[0167] The weighing device 112 ( Fig. 20 ) is used for weighing the straw 22 in portions before the subsequent mixing process.

[0168] The weighing device 112 comprises a trough 122 and a frame 123. The trough 122 is suspended from the frame 123 by means of load cells 124, in particular bending beam cells, which are connected to the control device 11.

[0169] The tub 122 has two end walls 122a, two side walls 122b, a lid 122c, and a bottom wall 122d. The bottom wall 122d is preferably divided into two parts and has two bottom flaps 125, which are pivotably mounted on each of the side walls 122b. In particular, the two bottom parts 125 are pivotable such that they can pivot or fold to the side, forming an opening in the bottom through which the straw 22 can fall out of the tub 122. For pivoting the two bottom flaps 125, the tub 122 also has corresponding drive means, preferably electric or pneumatic, preferably pneumatic linear cylinders. Electric and pneumatic rotary actuators can also be used.

[0170] The tub lid 122c also has a filling opening 126 through which the straw 22 is filled into the tub 122.

[0171] To close the filling opening 126, the weighing device 112 has a shut-off or closing slide 127. The closing slide 127 is slidable back and forth parallel to the tub lid 122c from a position closing the filling opening 126 to a position releasing it. For pivoting the closing slide 127, the weighing device 112 also has corresponding drive means, preferably electric or pneumatic, preferably pneumatic linear cylinders. Furthermore, the closing slide 127 is mounted on the frame 123 independently of the tub 122.

[0172] In addition, the closing slide 127 has a slide base plate 127a, two slide side walls 127b and a slide rear wall 127c.

[0173] Preferably, the calcium hydroxide is also added in the weighing device 112. For this purpose, the tub lid 122c has a corresponding calcium inlet opening.

[0174] The lime hydrate supply device 6 described above is located above the lime inlet opening.

[0175] The weighing device 112 also has two boundary walls 128 that extend away from the tub lid 122c and define the filling opening 126. The two boundary walls 128 are parallel to the slide gate rear wall 127c. The two boundary walls 128 are also mounted on the frame 123 independently of the tub 122.

[0176] In the releasing position, the slide plate 127a is not vertically aligned with the filling opening 126. As soon as the desired fill quantity is reached, the outlet opening of the cyclone separator 111 is closed by moving the closing slide 127 into the closing position.

[0177] In the closing position, the slide gate base plate 127a is arranged vertically aligned with the filling opening 126 and closes it off. Furthermore, the two boundary walls 128 and the two slide gate side walls 127b, together with the slide gate base plate 127a, form an upwardly open collection container 129 for the straw 22, which trickles out of the cyclone separator 111 after the filling opening 126 is closed. This ensures that the trough 122 is filled with a precisely defined quantity of straw. This quantity is preferably between 2.0 and 10.0 kg, more preferably between 2.1 and 6.0 kg.

[0178] As soon as the filling opening 126 is closed, the two bottom flaps 125 are swung to the side and the straw 22 falls through the formed trough bottom opening into the screw mixer 113 according to the invention.

[0179] The screw mixer 113 has a mixing trough 130 for receiving the material to be mixed, at least two mixing screws 131;132 arranged one above the other and two mixing screw drive motors 133;134.

[0180] Both mixing screws 131;132 are each driven individually by a mixing screw drive motor 133;134, in particular an electric motor. This allows the rotational speeds and the mixing energy input to be precisely controlled and adapted to the material being mixed.

[0181] The mixer trough 130 has two opposing trough end walls 130a, two trough side walls 130b, and a trough bottom wall. The two supporting side walls 130b converge towards the trough bottom wall, so that the mixer trough 130 tapers downwards.

[0182] The mixing trough 130 is sealed dust-tight at the top by the weighing device 112. A trough lid is therefore preferably not provided.

[0183] This ensures that there is sufficient space for the straw 22 to expand. It was found within the scope of the invention that a tubular mixing chamber leads to blockages during the mixing process. It is evidently important that the straw 22 can expand upwards during the mixing process and is not compacted by the mixing augers 131;132 due to a limiting lid surface. Thus, the straw 22 does not come into contact with the bottom wall 122d of the trough during the mixing process.

[0184] As already explained, the screw mixer 113 also has at least two mixing screws 131;132 arranged one above the other. The two mixing screws 131;132 each have a screw axis of rotation 131a;132a, a screw shaft 131b;132b and a screw vane or screw thread 131c;132c.

[0185] The screw wing 131c of the first, in particular lower, mixing screw 131 is formed from two opposing wing sections 135a;b. The two wing sections 135a;b have such an opposing slope that the lower mixing screw 131 conveys the material to be mixed towards the center of the mixing trough 130 and away from the two trough end walls 130a.

[0186] In the area where the two opposing wing sections 135a;b meet, at least one of the two trough side walls 130b has a trough outlet opening 136, which can be closed by means of a closing slide 137. For moving the closing slide 137, the mixer trough 130 has corresponding drive means, preferably electric or pneumatic, preferably pneumatic linear cylinders.

[0187] In addition, the first, especially lower, mixing screw 131 has a radially arranged discharge plate 141 in the middle of the mixing screw 131, where the two opposing wing sections 135a;b meet.

[0188] The screw wing 132c of the second, in particular upper, mixing screw 132 is also formed from two opposing wing sections 138a;b. However, the two wing sections 138a;b have such an opposing slope that the upper mixing screw 132 conveys the material to be mixed away from the center of the mixing trough 130 and towards the two trough end walls 130a.

[0189] Since the lower mixing screw 131 conveys towards the center and the upper mixing screw 132 conveys away from the center, two essentially circular mass flows are formed. These flows are conveyed towards the center in the lower section and are pulled apart again in the upper section. They are continuously divided and recombined, which is a particularly advantageous feature of the mixing process.

[0190] Furthermore, the second, in particular the upper, mixing screw 132 has several teeth 139 that project outwards in a radial direction from the screw wing 132c in relation to the screw axis of rotation 132a. In particular, they project from an outer edge 140 of the screw wing 132c.

[0191] The teeth 139 serve to break up any conglomerates or accumulations during the mixing process and to loosen the mixture in general.

[0192] The teeth 139 also have two intersecting tooth edges 139a;b and a tooth tip 139c, wherein the tooth edges 139a;b preferably form an obtuse angle with each other. Furthermore, the teeth 139 are spaced apart from each other by 20° to 90°, preferably 30° to 45°, in a circumferential direction with respect to the worm rotation axis 132a.

[0193] Furthermore, the serrations 139 preferably have a height of 20 mm to 60 mm, more preferably 30 mm to 40 mm. The height of the serrations corresponds to the distance from the serration tip 139c to the outer edge of the wing 140.

[0194] The binder addition device 114 serves to add the liquid binder mixture described above to the straw 22. Preferably, the mixing trough 130 has several binder inlets distributed radially around the upper mixing screw 132. This prevents binder clumping and sticking. The binder inlets are supplied with the binder mixture by the binder addition device 114. Preferably, the binder mixture is filled without nozzles.

[0195] Furthermore, the addition of the binder is preferably only started when the mixer trough 130 is filled with at least 20% by mass, preferably at least 30% by mass of the straw quantity.

[0196] Once the mixing process is complete, as already explained, the trough outlet opening 136 is opened, and the lower mixing screw 131 conveys the finished mixture radially out of the screw mixer 113 with the discharge plate 141. This occurs gradually and evenly. Furthermore, the discharge velocity can be controlled by the rotational speed of the mixing screws 131 and 132. This uniform discharge forms the basis for further conveying of the mixture with compressed air.

[0197] Straw 22 mixed with binder is conveyed from the screw mixer 113 to the distribution device 92 via the conveying line 116.

[0198] Preferably, the dense straw panels 13 are used as carrier panels, preferably as plaster carrier panels or as heating carrier panels, or as acoustic panels.

[0199] Furthermore, the dense straw panels 13 preferably have a density of 200 to 520 kg / m 3< , preferably 210 to 240 kg / m 3< , particularly preferably 210 to 230 kg / m 3< , according to DIN EN 1602:2013-05.

[0200] Preferably the dense straw panels 13 also have a compressive strength of 3.0 to 4.0 N / mm 2< , preferably of 3.3 to 3.8 N / mm 2< , according to DIN EN ISO 29469:2023-02.

[0201] An advantage of the device 1 according to the invention is that it ensures the production of straw boards 12;13 with excellent and uniform quality. This is achieved in particular by a uniform mixing of the straw 22 with the liquid binder mixture.

[0202] As already explained, evenly mixing the straw 22 with the binder mixture is not easy, as the straw 22 tends to form material accumulations and clumps.

[0203] The mixer forks 62 can effectively break up these material accumulations with their spring-loaded tines 66, thus avoiding force peaks that could lead to damage.

[0204] Furthermore, the division of the mixing chamber 57a into the individual vertically stacked mixing chambers 51c according to the invention, and the insertion and removal of the intermediate floor sections 60, regulate the conveyance of the straw 22. This prevents the individual mixing chambers 51c from becoming overfilled. And with this enforced separation of the straw mass flow and the equally enforced residence time of the straw 22 in the individual mixing chambers 51c, a high mixing quality is achieved.

[0205] In the cyclone separator 50, the straw 22 is separated from the transport air. This ensures that the multi-level mixer 51 only operates with straw lengths that are within the stable operating limits of the multi-level mixer 51.

[0206] Furthermore, a uniform application of the straw 22 mixed with the binder mixture onto the conveyor belt 69 of the press 10 is important for the properties of the subsequent straw insulation boards 12. In particular, the arrangement of the individual straw stalks influences both the density distribution and the mechanical properties of the straw insulation board 12. A problem here is that the straw-binder mixture is neither free-flowing nor pourable. It is therefore advantageous if it is actively broken up and laid down again to avoid local density differences in the straw insulation board 12. Within the scope of the invention, it was found that a loose, undirected arrangement of the straw stalks is advantageous, so that the subsequent compaction results in optimal interlocking of the straw stalks with one another.This avoids the formation of separating layers caused by oriented straw stalks, which negatively affect the mechanical properties of the straw insulation boards 12. In particular, alignment or layering of the straw stalks should be avoided, as this can lead to weak points in the straw insulation board.

[0207] As already explained, the optimal application of the straw 22 onto the conveyor belt 69 is achieved by means of the throwing device 68. The rotating shovel 76 simultaneously breaks up any clumps and lumps in the straw-binder mixture and throws the straw-binder mixture onto the conveyor belt 69.

[0208] In particular, the straw-binder mixture is thrown in a parabolic shape onto the moving conveyor belt 69, where it settles according to a Gaussian normal distribution. This results in a uniformly thick layer of straw on the conveyor belt 69. This homogenization process ensures a uniform density distribution of the straw layer in the conveying direction 82 and transforms the individual straw portions coming from the mixing device 8 into a uniform mass flow.

[0209] Furthermore, the activation of the binder during the production of the straw insulation boards 12 using steam is advantageous.

[0210] Because the straw is used as an insulator in the application for the production of straw insulation boards, activation using the usual contact heat method is not optimal due to the poor thermal conductivity of the straw.

[0211] In contrast, using steam for heating allows for efficient and very rapid heating of the entire straw layer due to various physical effects. The steam condenses and transfers the released condensation energy to the binding agent, thereby bringing the binder directly to its activation temperature.

[0212] The phase transition of the steam to the liquid phase also creates local negative pressures, which draw in further steam and thus ensure complete, defect-free heating of the entire straw layer. This reliably activates the binder in every area. The introduction of steam also temporarily softens the straw stalks and reduces their resilience. This reversible change in the straw allows for faster forming and demolding of the compressed straw strand without the lengthy calibration periods that would otherwise be necessary until the binder reaches its final strength after drying.

[0213] Furthermore, it is very advantageous to add the hydrated lime separately from the binder. Since the hydrated lime is not mixed with the binder, it is at least partially free of binder and has a larger free surface area. This makes it more reactive. Adding hydrated lime to the liquid binder mixture would also thicken the binder mixture.

[0214] Another advantage is that the production process is essentially carried out with the straw still damp. The straw is only moistened with the binding agent, and the straw stalks are only bonded together at the contact points.

[0215] Within the scope of the invention it is also possible to produce the insulating straw panels 12 with the device according to the second embodiment of the invention and to produce the dense straw panels 13 with the device according to the first embodiment of the invention, even if the reverse is preferred.

[0216] It is also of course possible that the device 1 has several parallel-operated plate pressing devices 10;14.

[0217] The screw mixer, as described above, is particularly advantageous and the preferred mixing device. The rapid movement of the material through the mixing screws in the screw mixer also incorporates air into the mixture. The serrations on the upper mixing screw contribute significantly to this effect. This alters the properties of the straw, which otherwise tends to form conglomerates and clumps, and causes it to behave more like a fluid. As a result, the material flows through the screw mixer in the streams described above, achieving excellent mixing quality while maintaining a very robust mixer design. The solid screw construction is resistant to blockages and damage from compacted fiber-binder clumps. Only two moving parts are involved in the mixing process – the two mixing screws.Thanks to the easily accessible yet enclosed design of the mixing chamber and the externally mounted motors, the screw mixer is very low-maintenance and requires minimal upkeep. The encapsulated mixing chamber is airtight and reduces dust emissions to a minimum.

[0218] Furthermore, it is self-evident within the scope of the invention that the different components of the various embodiments of the devices 1 are combined with each other without deviating from the scope of the attached claims.

[0219] For example, the multi-level mixer 51 and the screw mixer 113 can be exchanged for each other.

[0220] This also applies to the vibrating trough 5 and the homogenizing conveying screw 119. The only important thing is that a homogenizing device is present which homogenizes the straw 22 so that it becomes air-conveyable.

[0221] Furthermore, the stone separator 107 and / or the straw witch 108 can of course also be installed in the devices 1 according to Figure 1 and 2 to be integrated. Both the stone separator 107 and the straw shredder 108 must always be positioned in front of the mixing unit 8.

[0222] Furthermore, it is particularly advantageous if the weighing device 4;112 is arranged shortly before the respective mixer 51;113, preferably directly before it. It is then also available in the embodiments according to Figure 1 and 2 preferably arranged between the cyclone separator 50 and the multi-stage mixer 51. This ensures particularly precise dosing and accurate mixing of straw, binder mixture and hydrated lime.

[0223] And in particular, the addition of hydrated lime in the weighing device 112, i.e. after the air conveyance, is also advantageous for all embodiments, since otherwise there is a risk that the hydrated lime will separate again from the straw 22 due to the air conveyance.

[0224] The calcium hydroxide feeding device 6 can also be used very advantageously in the production of other fiberboards or particleboards for adding calcium hydroxide to the fibers, especially the straw, or the shavings.

Claims

1. Device (1) for producing straw plates (12;13), comprising a) a straw bale dissolving device (2) for dissolving and loosening a straw bale (15), b) a weighing device (4; 112) for portioning a desired amount of loosened straw (22), c) a mixing device (8) for mixing the straw (22) with a liquid, heat-curing binder mixture, d) a continuous plate pressing device (10) for compacting the straw (22) mixed with the binder mixture into a continuous straw strand, curing the binder mixture and cutting the straw strand into individual straw plates (12), or a discontinuous plate pressing device (14) for pressing the straw (22) mixed with the binder mixture into individual straw plates (13) and curing the binder mixture, e) a control device (11) for controlling the production process, characterized in that the mixing device (8) comprises f1) a screw mixer (113) with at least two mixing screws (131;132) arranged one above the other, or f2) a multi-stage mixer (51) with several, preferably 3 to 10, preferably 4 to 5, mixing chambers (51c) arranged one above the other, wherein the mixing chambers (51c) of the multi-stage mixer (51) are separated from one another by, in particular horizontal, intermediate bottoms (63), which can be opened at least partially towards the mixing chamber (51c) respectively located below.

2. Device according to claim 1, characterized in that the screw mixer (113) comprises a mixing trough (130), the at least two mixing screws (131;132) arranged one above the other, and at least one, preferably two, mixing screw drive motors (133;134).

3. Device according to claim 1 or 2, characterized in that the two mixing screws (131; 132) each comprise a screw rotation axis (131a;132a), a screw shaft (131b;132b) and a screw blade (131c;132c), wherein the screw blade (131c) of the lower mixing screw (131) preferably comprises two blade sections (135a;b) which comprise a counter-rotating slope such that the lower mixing screw (131) conveys the material to be mixed, seen in a direction parallel to the screw axis (131a), towards the center of the mixing trough (130).

4. Device according to claim 3, characterized in that the screw blade (132c) of the upper mixing screw (132) comprises two counter-rotating blade sections (138a;b) that comprise a counter-rotating slope such that the upper mixing screw (132) conveys the material to be mixed away from the center of the mixing trough, seen (130) in a direction parallel to the screw rotation axis (132a).

5. Device according to claim 3 or 4, characterized in that the upper mixing screw (132) comprises a plurality of spikes (139) which project radially outwards from the screw blade (132c) in relation to the screw rotation axis (132a), preferably from an outer blade edge (140) of the screw blade (132c).

6. Device according to claim 5, characterized in that a) the spikes (139) comprise two interlocking spike edges (139a;b) and a spike tip (139c), wherein the spike edges (139a;b) preferably form an obtuse angle with each other and / or b) the spikes (139) are spaced apart from each other by 20° to 90°, preferably 30° to 45°, when viewed in a circumferential direction relative to the screw rotation axis (132a), and / or c) the spikes (139) comprise a height of 20 mm to 60 mm, preferably 30 mm to 40 mm.

7. Device according to one of claims 3 to 6, characterized in that the mixing trough (130) comprises a trough outlet opening (136) in an area where the two inverse blade sections (135a;b) of the lower mixing screw (131) meet, which can be closed and opened by means of a shutoff slide (137), and preferably, the lower mixing screw (131) comprises a radially arranged discharge plate (141) in the center of the mixing screw (131), where the two inverse blade sections (135a;b) meet.

8. Device according to one of claims 1 to 7, characterized in that the weighing device (112) is, preferably immediately, arranged in front of the mixing device (8), in particular in front of the screw mixer (113) or the multi-stage mixer (51).

9. Device according to claim 1 or 8, characterized in that the intermediate bottoms (63) each have at least one movable intermediate bottom part (60) which can be moved out of and into a mixer interior (57a) by means of drive means.

10. Device according to claim 9, characterized in that a) each intermediate bottom (63) comprises two movable intermediate bottom parts (60) which can be pivoted out of and into the mixer interior (57a) by means of drive means, wherein the two movable intermediate bottom parts (60) can preferably be moved towards and away from each other in a scissor-like manner, and / or b) the intermediate bottoms (63) each comprise at least one fixed or immovable intermediate bottom part (59), and / or c) the intermediate bottoms (63) can each be opened independently of one another, preferably the movable intermediate bottom parts (60) of the individual intermediate bottoms (63) can each be moved independently of one another.

11. Device according to one of claims 1,8 to 10, characterized in that the multi-stage mixer (51) comprises at least one mixer fork (62) per mixing chamber (51c), which comprises at least two tines (66), wherein the mixer fork (62) is fixed at one end to a mixer shaft (58) that can be rotated about a mixer shaft rotation axis (58a) and protrudes radially from the mixer shaft (58) in relation to the mixer shaft rotation axis (58a), wherein the tines (66) of a mixer fork (62) are preferably arranged vertically one above the other and aligned with each other, wherein the tines (66) preferably have an undeflected initial position in which they preferably extend in a radial direction relative to the mixer shaft rotation axis (58a) and can be deflected from the initial position about a preferably vertical tine rotation axis (66a) in two opposite directions against spring force.

12. Device according to one of the preceding claims 1, 8 to 11, characterized in that the multi-stage mixer (51) comprises a binder addition device (61) for adding the liquid binder mixture, wherein the binder addition device (61) is preferably arranged such that the addition takes place in the uppermost mixing chamber (51c), preferably above a fixed intermediate bottom part (59) of the intermediate bottom (63) of the uppermost mixing chamber (51c).

13. Device according to one of claims 1 to 12, characterized in that the device (1) comprises a hydrated lime feeding device (6) for feeding hydrated lime separately from the binder mixture, wherein the hydrated lime feeding device (6) comprises a storage container (37) for receiving the hydrated lime, preferably a mixing shaft (39) with at least one mixing rod (40), as well as a rotary valve (41) with a blow-out device (46) for blowing the hydrated lime out of the rotary valve (41) and a drive motor (38) for driving the rotary valve (41).

14. Device according to claim 13, characterized in that a) the mixing shaft (39) is connected to the drive motor (38) so that it can be driven to rotate about a mixing shaft rotation axis (39a) and / or is arranged above the rotary valve (41), and / or b) the rotary valve (41) comprises a rotary valve wheel (42), a valve housing (43), a valve inlet (41a) and a valve outlet (41b), wherein the valve inlet (41a) is preferably arranged vertically aligned below the mixing shaft (39), wherein the rotary valve disc (42) preferably comprises a rotary valve wheel rotation axis (42a) and a plurality of cells (44) adjacent to one another in the circumferential direction for receiving the hydrated lime, wherein the cells (44) are designed groove-like and preferably comprise a longitudinal extension parallel to the rotary valve wheel rotation axis (42a), and wherein a cell wall of the cells (44) preferably comprises a circular arc-shaped, preferably semicircular cross-section, wherein the cross-section preferably extends over at most 180°.

15. Device (6) according to claim 14, characterized in that the valve housing (43) has a blow-out channel (45) in the area of the valve outlet (41b), wherein the blow-out channel (45) comprises a channel inlet end (45a) and a channel outlet end (45b), both of which open into the environment, and wherein the blow-out device (46) comprises a compressed air source (47) for the continuous supply of compressed air, which is connected to the channel inlet end (45a), and wherein the blow-out channel (45) is designed such that it respectively is in fluid communication with the cell (44) located in the area of the valve outlet (41b), wherein the blow-out channel (45) preferably has a U-shaped course.

16. Device according to one of claims 1 to 15, characterized in that a) the device (1) comprises at least one radial fan (36; 93;109;115) and a conveyor channel (7;110;116) for conveying the straw (22) by means of conveyor air, and / or b) the device (1) comprises a stone separator (107) for separating the straw (22) from heavier particles, e.g. stones and / or dirt and / or grains and / or metal, wherein the stone separator (107) is arranged before the mixing device (8) and preferably before the weighing device (112), and / or c) the device (1) comprises a straw chopper (108) for at least partially splitting the straw stalks and for chopping them to a predetermined stalk length, preferably to a stalk length of 10 mm to 60 mm, preferably 20 mm to 40 mm, wherein the straw chopper (108) is arranged before the mixing device (8) and preferably before the weighing device (112), wherein the straw chopper (108) is also preferably arranged after the stone separator (107), and / or d) the device (1) comprises a homogenizing device for homogenizing the straw (22), which is preferably arranged directly after the straw bale dissolving device (2), wherein the homogenizing device is preferably a homogenizing screw (106) which has a collection container (118) and a homogenizing conveyor screw (119) connected thereto, or a vibrating chute (5).

17. Device according to one of claims 1 to 16, characterized in that the pressing device (14) comprises, arranged one after the other in the conveying direction (82), a receiving device (87), a press (88) and, preferably, a trimming device (89), wherein the receiving device (87) preferably comprises a drivable receiving conveyor belt (90), two boundary walls (91) arranged at a distance from each other in the horizontal direction, and a distribution device (92).

18. Device according to claim 17, characterized in that a) the pressing device (14) comprises means for applying the straw (22) in a meandering pattern, preferably in a cross-bonded manner, onto a substrate, preferably onto the receiving conveyor belt (90), and / or b) the press (88) comprises two heatable press plates (94) arranged one above the other for applying temperature to the straw (22) mixed with the thermosetting binder mixture during the pressing process.

19. Device according to one of claims 1 to 16 for the production of straw insulation boards (12), characterized in that the continuous plate pressing device is a continuous insulation plate pressing device, wherein the continuous insulation plate pressing device (10) comprises a conveyor belt (69), a throwing device (68) for throwing the straw (22) onto the conveyor belt (69), a compaction and binder activation device (70) for compacting the straw mixed with the binder mixture (22) into a continuous straw strand and for curing the binder mixture, preferably a drying device (72) for drying the straw strand, and a cutting device (73) for cutting the straw strand into the individual straw plates (12), wherein the throwing device (68) preferably comprises a collecting container (75), a shovel (76) which can be driven to rotate about a shovel rotation axis (76a), and a drive motor (77) for driving the shovel (76), wherein the shovel (76) preferably comprises a hollow cylindrical shovel shaft (80) formed with rotational symmetry relative to the shovel rotation axis (76a) and a single shovel blade (81) which protrudes from the shovel shaft (80) in the radial direction relative to the shovel rotation axis (76a).

20. Device according to claim 19, characterized in that a) the collection container (75) comprises a curved container wall (78a) and two adjoining container side walls (78b) which are arranged opposite each other, seen in the direction of the shovel rotation axis (76a), wherein the curved container wall (78a) is preferably designed to be rotationally symmetrical to the shovel rotation axis (76a) and is designed as a cylinder jacket section. and / or b) the collection container (75) is open at the top and comprises a container opening (75a) and a container interior (75b), wherein preferably straw (22) located in the container interior (75b) can be removed from the collection container (75) by rotation of the shovel (76) by means of the shovel(76), in particular by means of the shovel blade (81).

21. Device according to claim 19 or 20, characterized in that the continuous insulation plate pressing device (10) comprises, in particular vertical, side walls (83) on both sides of the conveyor belt (69), which are opposite each other in a direction parallel to the shovel rotation axis (76a) and preferably extend to the throwing device (68) and shield it laterally.

22. Method for producing straw plates (12;13) using a device (1) according to one of the claims 1 to 21, with the following method steps: a) Dissolving and loosening a straw bale (15), b) weighing and portioning a desired amount of loosened straw (22), c) mixing the straw (22) with a liquid binder mixture, d) Compacting the straw (22) mixed with the binder mixture into a continuous straw strand, curing the binder mixture and cutting the straw strand into individual straw plates (12) or, while simultaneously curing the binder mixture, pressing the straw (22) mixed with the binder mixture into individual straw plates (13).

23. Method according to claim 22, characterized in that a) curing of the binder mixture is carried out by applying temperature to the binder mixture, and / or b) the straw (22) is comminuted and preferably split before being mixed with the binder mixture.