Methods and apparatus for the production of straw panels

Abstract

The present invention relates to a method and apparatus (1) for the production of straw boards (12,13) ​​and a calcium hydroxide supply device (6) therefor.

Description

[0001] The present invention relates to a method and devices for producing straw boards and a hydrated lime supply device therefor.

[0002] EP 2 799 639 A1 discloses an insulation board for insulating a building facade. The insulation board is made of straw held together by an adhesive. The adhesive can be glue, in particular vegetable glue, or starch glue. The insulation board is produced by mixing preferably chopped straw with the adhesive, gently pressing the straw-adhesive mixture to form an insulation board, and allowing the thus-produced insulation board to stand to dry. To dry, the insulation board is preferably heated, in particular to a temperature of approximately 25-50°C.

[0003] DE 198 10 862 A1 describes an insulation board made of straw in which the fiber length of the straw is a maximum of 150 mm, the straw is shredded into fibrous pieces and the closed stalk structure is destroyed by longitudinal splicing, 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 minimum thickness of the board is 30 mm and the bulk density is 40 to 100 kg / m³. The board is also provided on both sides with a flexible, grid-like natural fiber coating. Preferably, the straw fibers largely have a length of at least 2 mm or more. The insulation board is manufactured by shredding the straw into fibrous pieces and splicing the straw lengthwise into a fraction with fiber lengths of up to 150 mm.The fiber fraction is then homogeneously mixed with a biodegradable binder containing an excess of water, and the mixture is continuously applied to a binder-impregnated coating material web, subjecting it to slight deformation. The fiber fraction is preferably mixed with the binder and flame retardant in a mixing device. The homogeneous mixture is then conveyed by a conveyor belt into a mixing silo, which has a discharge roller at the lower end and is arranged above a plate conveyor belt on which the impregnated coating material web is arranged.

[0004] A top coating layer impregnated with a binder is applied to the resulting insulation sheet. The resulting insulation sheet is conveyed through a heating zone, dried, and optionally vulcanized. This is preferably done using a hot air flow process with a hot air temperature of approximately 100°C. During drying, the binder is dried or vulcanized, with the resulting steam serving as a heat transfer medium and promoting vulcanization. The dried sheet is then cut into sheets.

[0005] The object of the present invention is to provide a cost-effective method and a device for producing straw panels, which ensures a uniform and good quality of the straw panels produced.

[0006] Another task is to provide a hydrated lime feeding device for the precise addition of hydrated lime to the straw.

[0007] These objects are achieved by a hydrated lime supply device according to claim 1, a device according to claims 4 and 19, and a method according to claim 22. Advantageous developments of the invention are characterized in the subsequent subclaims.

[0008] The invention is explained in more detail below using a drawing as an example. The drawings show: Figure 1: A simplified, schematic representation of the device according to the invention according to a first embodiment of the invention Figure 2: A simplified, schematic representation of the device according to the invention according to a further embodiment of the invention Figure 3: A simplified, schematic side view of a straw bale breaking-up 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 lime feed device Figure 7: A perspective view of the hydrated lime feed device Figure 8: A longitudinal section of the hydrated lime feed device Figure 9: A perspective, half-sectioned view of the hydrated lime feed device Figure 10: A simplified, schematic longitudinal section through a mixing device according to the invention and a cyclone separator Figure 11: A simplified,schematic cross-section through a multi-level mixer of the mixing device 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 device and an insulation board pressing device without a cutting device Figure 15: A perspective view of an area of ​​the insulation board pressing device Figure 16: Another perspective view of an area of ​​the insulation board pressing device without a side wall Figure 17: A perspective view of a throwing device of the insulation board pressing device Figure 18: A simplified,schematic side view of a plate pressing device according to the further embodiment of the device according to the invention Figure 19: A highly simplified and schematic representation of the device according to the invention according to the further embodiment of the invention with further conveying means between the mixing device and the plate pressing device Figure 20: A simplified, schematic representation of the device according to the invention according to a further embodiment of the invention Figure 21: A perspective view of a further weighing device, closing slide in 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: A part of a plan view of the screw mixer according to the invention Figure 25: A part of a side view of the screw mixer according to the invention,

[0009] The device 1 according to the invention serves for the production of straw panels 12; 13. The straw panels 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 bonds the individual straw stalks together.

[0010] According to a first embodiment of the invention ( Fig. 1) The device 1 according to the invention is used to produce insulating straw panels 12 or straw insulation panels 12 and has, arranged downstream, a straw bale breaking device 2, a conveyor channel 3, a weighing device 4, a vibrating trough 5, a hydrated lime supply device 6, preferably a further conveyor channel 7, preferably a cyclone separator (50), a mixing device 8 according to the invention and preferably a further conveyor channel 9, and an insulation panel pressing device 10. In addition, the device 1 has a control device 11 for controlling the production process.

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

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

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

[0014] Such straw bale breaking devices 2 are used, for example, in horse stables. By means of the straw bale breaking device 2, the straw bales 15 are broken up and loosened without shredding the straw stalks.

[0015] The straw bale breaking device 2 preferably comprises, in a conventional manner, a housing 16, a milling belt 17, an abutment plate 18, a receiving hopper 19, and a discharge conveyor screw 20. The milling belt 17, the abutment plate 18, and the receiving hopper 19 are arranged in the housing 16. The discharge conveyor screw 20 is partially arranged in the housing 16 and opens into the environment or leads outside.

[0016] For opening and loosening, the straw bale 15 is placed on the rotating milling belt 17 and pressed by it against the abutment plate 18, which is arranged above the end of the horizontal milling belt 17. The straw bale 15 is opened by the milling edges 21 of the milling belt 17, and the opened and loosened straw 22 falls from the milling belt 17 at the end of the milling belt 17 into the receiving hopper 19. The receiving hopper 19, in turn, opens into the discharge conveyor screw 20, which conveys the straw 22 out of the housing 16 into the conveyor channel 3.

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

[0018] As already explained, the straw 22 is conveyed into the conveying channel 3 and through it to the weighing device 4. Preferably, the conveying takes place solely by the conveying pressure generated by the discharge conveyor screw 20.

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

[0020] The detection of the delivery pressure serves to keep the delivery rate constant. If deviations from the target delivery pressure are detected, the straw bale breaking device 2 is controlled to provide more or less straw 22. The straw bale breaking device 2 is thus controlled, among other things, based on the delivery pressure measured by the sensor 23.

[0021] By means of the milling drum 24, the straw 22 is conveyed in portions into the weighing device 4. For this purpose, the milling drum 24 has milling edges 24a in a conventional manner. By means of the milling edges 24a, individual straw portions are separated from the straw composite, and one straw portion is picked up between two adjacent milling edges 24a and conveyed into the weighing device 4. The straw 22 is deflected or guided by the deflection 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 dozer 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 then conveyed in portions into the trough 26 by means of the milling roller 24 and weighed therein. 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 fed into the trough 26 in portions until the desired amount of straw 22 is reached. This amount is preferably between 2.0 and 10.0 kg, preferably between 2.1 and 4.2 kg.

[0025] Once the desired amount of straw has been reached, the milling drum 24 is stopped, and the weighed straw portion 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 trough end 26 to the second trough end 26b, and the straw 22 is thereby pushed out of the trough 26 at the second trough end 26a and conveyed into the vibrating chute 5.

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

[0027] To implement the vibrating or rocking motion of the trough wall 30, the trough wall 30 is secured to the ground by means of projection arms 31. For this purpose, the projection arms 31 are attached to the ground at one end so that they can rotate about a horizontal axis, and are attached to the trough wall 30 at the other end so that they can rotate about a horizontal axis. Furthermore, the vibrating trough 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 trough wall 30 and at the other end eccentrically to a drive pulley 33, which in turn is rotatably connected to a drive motor.

[0028] The straw 22 is conveyed in a conventional manner by the vibrating or rocking motion of the vibrating chute 5. As a result, the straw 22 is thrown forward at regular intervals, in a chute 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 chute 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, the addition of hydrated lime dust to the straw 22 now takes place at the upper trough end 5b. For this purpose, the hydrated lime supply device 6 is arranged at the upper trough end 5b above the trough wall 30.

[0030] In addition, the trough wall 30 has a discharge edge 34 at the upper trough end 5, from which the straw 22 falls. Preferably, a trough bottom 30a of the trough wall 30 at the upper trough end 5b has a downwardly bent profile, so that the straw 22 falls more easily out of the trough wall 30.

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

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

[0033] The hydrated lime feed device 6, as already explained, serves to add very fine, powdered hydrated lime (Ca(OH) 2 ). In particular, the hydrated lime has a grain size of ≤ 100 µm, preferably ≤ 90 µm, according to DIN EN 459-1:2015-07. The hydrated lime serves to adjust certain properties of the straw insulation boards 12 to be produced.

[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 influences the surface hardness of the straw insulation boards 12.

[0035] This requires a very precise dosage of hydrated lime.

[0036] A problem with dosing is that the very fine hydrated lime is very prone to clumping and bridging when lightly compacted. Consequently, the hydrated lime feed device 6 preferably has a special design:

[0037] The hydrated lime feed device 6 ( Fig. 1 , 2 , 7 , 8 , 9 ) has a storage container 37 for holding 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 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 container interior 37b. It is also mounted at both ends in the container wall 37a, each rotatable about its horizontal mixer shaft rotation axis 39a. Furthermore, the mixer shaft 39 is connected to the drive motor 38 so that it can be driven rotatably about its mixer shaft rotation axis 39a. The mixer rods 40 extend radially away from the mixer shaft 39 relative to the mixer shaft rotation axis 39a.

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

[0041] The drive motor 38 is preferably a stepper motor. The stepper motor ensures a precise speed and thus precise dosing of the hydrated lime. However, it can also be a servo motor. It can also be a DC or three-phase motor. Furthermore, the drive motor 38 is preferably mounted on the outside of the storage container 37.

[0042] As already explained, the rotary valve 41 is arranged below the mixer shaft 39. It comprises 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 cellular wheel 42 has a cellular wheel rotation axis 42a and a plurality of circumferentially adjacent cells 44 for receiving the hydrated lime. The cells 44 are groove-like and have a longitudinal extension parallel to the cellular wheel rotation axis 42a. The cells 44 extend radially into the cellular wheel 42 relative to the cellular wheel rotation axis 42a.

[0045] In addition, a cell wall of the cells 44 preferably has a circular, 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 powdered hydrated lime from the cells 44. In particular, falling out is facilitated compared to cells with a square, especially triangular, cross-section.

[0046] Preferably, the cells 44 each have a volume of 300 mm 3< to 3000 mm 3< , preferably 400 mm 3< to 800 mm 3< .

[0047] The cellular wheel 42 preferably has a delivery rate of 10,000 mm 3< / min to 500,000 mm 3< / min, preferably 30,000 mm 3< / min to 50,000 mm 3< / min.

[0048] In addition, the cellular wheel 42 is connected to the drive motor 38 so that it can rotate about the cellular wheel rotation axis 42a. Preferably, the cellular wheel 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 cellular wheel 42 and the mixer shaft 39 are thus synchronized, preferably mechanically and / or electronically. Consequently, the cellular wheel 42 is preferably connected to the drive motor 38 via the mixer shaft 39 so that it can rotate about the cellular wheel rotation axis 42a.

[0049] The cell wheel 42 is also mounted in the lock housing 43 in a manner known per se so as to be rotatable about the cell wheel rotation axis 42a.

[0050] Each cell 44 receives hydrated lime below the lock inlet 41a in a conventional manner, and the hydrated lime is conveyed out of the cell 44 at the lock outlet 41b. According to a particularly advantageous aspect of the invention, the hydrated lime is blown out of the cell 44 at the lock 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-out 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-out channel 45 in the region of the lock outlet 41b. The blow-out channel 45 has a channel inlet end 45a and a channel outlet end 45b, both of which open into the environment. Furthermore, the blow-out channel 45 is preferably U-shaped. The compressed air source 47 is connected to the channel inlet end 45a, for example, by means of a hose 48.

[0053] In addition, the blow-out channel 45 extends below the cellular wheel 42 and parallel to the cellular wheel rotation axis 42a from one end of the cellular wheel 42 to the other. The blow-out channel 45 is open toward the cellular wheel 42. As a result, the blow-out channel 45 is connected to the cell 44, which is in the lowest position.

[0054] As already explained, the compressed air source 47 preferably provides a constant supply of compressed air. As a result, compressed air flows constantly from the duct inlet end 45a to the duct outlet end 45b through the exhaust duct 45.

[0055] As soon as a cell 44 has rotated downward far enough that it is connected to the blow-out duct 45, the compressed air is blown not only through the blow-out duct 45, but also through the cell 44 connected to it. This blows the hydrated lime contained in the cell 44 out of the cell 44. The air / hydrated lime mixture is then blown out into the environment at the duct outlet end 45b or exits the lock housing 43 and the hydrated lime supply device 6. According to the invention, it exits in the form of a hydrated lime aerosol. This means that the hydrated lime particles are very finely distributed in the air.

[0056] The blow-out device 46 thus serves to reliably remove the hydrated lime from the cells 44. The constant air flow also completely removes lime dust deposits from the cells 44 and ensures a homogeneous introduction of the hydrated lime into the straw 22. In the blow-out duct 45, the air vortex generated by the compressed air also breaks up small lumps of hydrated lime, thus discharging them evenly in the air stream in powder form. The formation of the air vortex is promoted, among other things, by the U-shape of the blow-out duct 45.

[0057] As already explained, the hydrated lime supply device 6 is arranged at the upper chute end 5b above the chute wall 30. In particular, the channel outlet end 45b is arranged above the chute wall 30 such that the air / hydrated lime mixture emerging from the channel outlet end 45b is supplied to the straw 22 located in the vibrating chute 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 trough end 5b so that the straw 22 does not escape upwards.

[0059] By means of the hydrated lime feeding device 6, a very precise, portion-wise and homogeneous addition of the hydrated lime to the straw 22 in very small quantities is possible.

[0060] As already explained, the straw 22 mixed with the hydrated lime falls from the trough wall 30 into the collecting hopper 35 of the radial fan 36, which is located at the beginning of the additional conveying channel 7. By means of the air flow generated by the radial fan 36, the hydrated lime is sucked in and the straw 22 is conveyed through the additional conveying channel 7 via the cyclone separator 50 to the mixing device 8.

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

[0062] The cyclone separator 50 has, in a conventional manner, a cyclone inlet 50a, an upper air outlet 50b, and a lower material outlet 50c. The cyclone separator 50 is preferably 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 additional dry or liquid components can be added to the straw 22. In particular, the components are injected. For example, the components can be preservatives, in particular sodium lauryl sulfate, or other additives, in particular hydrophilizing 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. In the cyclone separator 50, the separation between air and straw 22 then takes place in a conventional manner. Due to the conical taper, the rotational speed of the straw 22 increases to such an extent that the straw 22 is thrown by centrifugal force against the inside of the cyclone wall 53 and decelerated to such an extent that it detaches from the flow and trickles downward 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 valve serves to convey the straw 22 from the cyclone separator 50 into the mixing device 8.

[0067] For this purpose, the mixer rotary valve 52 has a valve housing 55 and a rotary valve 56 arranged therein, as well as a drive motor (not shown) for the rotary valve 56. The rotary valve 56 is connected to the drive motor so as to be rotatable about a rotary valve axis, in particular a horizontal one, 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. This is because straw is generally less free-flowing than other bulk materials.

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

[0069] The multi-level mixer 51 has an upper mixer inlet end 51a and a lower mixer outlet end 51b, and a plurality of, preferably 3 to 10, more preferably 4 to 5, mixing chambers 51c arranged one above the other. Furthermore, the multi-level mixer 51 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, a plurality of fixed intermediate floor sections 59, a plurality of movable intermediate floor sections 60, a binder addition device 61, and a plurality of mixer forks 62. For each mixing chamber 51c, 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 a plurality of 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 fixed intermediate floor part 59.

[0074] The binder mixture is preferably added in liquid form. The binder addition device 61 preferably also 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] In addition, the binder mixture preferably contains at least one protein and / or starch. The at least one protein can be of animal or plant origin. Furthermore, the binder mixture can also contain additives and / or admixtures.

[0077] The mixer shaft 58 is arranged within the mixer wall 57. It has a vertical mixer shaft rotation axis 58a. Furthermore, the mixer shaft 58 is connected to the drive motor 100, which can be driven rotatably about the mixer shaft rotation axis 58a. The drive motor 100 is preferably an asynchronous motor, in particular with a bevel or worm gear. Furthermore, for reasons of space, the drive motor 100 is preferably arranged above the mixer wall 57. Furthermore, the drive motor 100 is thus spatially separated from the discharged mixed material and is thus protected from damage by dust and aerosols.

[0078] The mixer forks 62 each have a stem 65 and at least two prongs 66 projecting therefrom. The stem 65 is firmly attached at one end to the mixer shaft 58 and projects radially from the mixer shaft rotation axis 58a. The prongs 66 adjoin the stem 65 at the other end. The prongs 66 of a mixer fork 62 are preferably arranged vertically one above the other and in alignment 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-deflected position, the tines 66 extend radially relative to the mixer shaft rotation axis 58a. They are then arranged as an extension of the stem 65. And from the non-deflected position, the tines 66 can be deflected to 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 the non-deflected starting position.

[0080] Alternatively, the mixer forks 62 do not have a stem 65, but the two tines 66 are connected to each other via a spring 67. And the spring 67 is firmly attached to the mixer shaft 58. In this case, too, 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 buildup. It was discovered during the course of the invention that the straw 22 wetted with the binding agent mixture tends to clump. In the worst case, this can lead to clogging and blockages in the mixer system. With the spring-loaded tines 66, material buildup can be effectively broken up, and force peaks that would otherwise lead to damage in the system are avoided, as the tines 66 can deflect.

[0082] The fixed, horizontal intermediate floor sections 59 are preferably arranged vertically adjacent to one another and aligned with one another. Furthermore, the fixed, horizontal intermediate floor sections 59 have a crescent shape. In particular, the fixed intermediate floor sections 59, with their circular, convex peripheral floor wall 59a, are connected internally to the mixer wall 57 or adjoin it. A concave, also circular, peripheral floor wall 59b is arranged at a distance from the mixer shaft 58. The fixed intermediate floor sections 59 are thus firmly connected to the mixer wall 57.

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

[0084] The movable, horizontal intermediate floor parts 60 are also preferably arranged adjacent to one another in the vertical direction. They are also arranged in pairs.

[0085] In addition, the movable, horizontal intermediate floor parts 60 each have a circular, convex, peripheral floor wall 60a, a straight, peripheral floor wall 60b, and an arcuate, convex, outer peripheral floor wall 60c. The diameter of the circular, convex, peripheral floor wall 60a corresponds to the diameter of the concave, circular, peripheral floor wall 59b of the fixed intermediate floor parts 59. The straight, peripheral floor wall 60b also has a mixer shaft receiving recess 103.

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

[0087] According to the invention, the movable, horizontal intermediate floor parts 60 can also be moved 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 floor sections 60 are each rotatable about a vertical intermediate floor axis of rotation or hinged to bearing elements 104 of the mixer support frame 101. Furthermore, they each extend through a slot in the mixer wall 57. Furthermore, the movable, horizontal intermediate floor sections 60 are each connected to a pneumatic cylinder 105 that can be driven back and forth about the intermediate floor axis of rotation. The pneumatic cylinders 105 are preferably supported at one end on the mixer support frame 101 and at the other end on the respective movable intermediate floor section 60, in particular on its outer floor peripheral wall 60c.

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

[0090] In a retracted position, the movable, horizontal intermediate floor parts 60 are also arranged in vertical alignment with one another.

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

[0092] For this purpose, in particular, the circular, convex bottom peripheral walls 60a of the two movable intermediate bottom parts 60 abut in a form-fitting manner against the concave, circular, arc-shaped bottom peripheral wall 59b of the fixed intermediate bottom part 59. Furthermore, the two straight bottom peripheral walls 60b of the two movable intermediate bottom parts 60 also abut one another. And the mixer shaft 39 is arranged within the two mixer shaft receiving recesses 103.

[0093] As a result, 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 floors 63 separate the individual mixing chambers 51c from each other.

[0095] After the straw 22 has been mixed in a mixing chamber 51c for a specific time, in particular for 30 to 120 seconds, preferably 35 to 60 seconds, the two movable intermediate floor parts 60 are moved out of the mixer interior 57a. As a result, the straw 22 falls onto the intermediate floor 63 of the mixing chamber 51c located below. This process is repeated until the straw 22 reaches the mixer outlet end 51b. At the mixer outlet end 51b, the thoroughly mixed straw 22 then falls out of the multi-level mixer 51 and, in particular, into another conveyor channel 9, through which the straw 22 is conveyed to the insulation board pressing device 10.

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

[0097] As already explained, it was discovered within the scope of the invention that straw 22 wetted with the binding agent mixture tends to clump and clog during mixing. The advantage of the multi-level mixer 51 is that the mass flow of straw 22 is broken down by the mixing chambers 51c. Nevertheless, the mixing process is essentially continuous. The mixing chamber is divided into individual, stacked mixing chambers 51c. The movable intermediate floor sections 60 regulate the further conveyance of straw 22 by regulating the opening times of the intermediate floor sections 60 accordingly. This prevents overfilling of the individual mixing chambers 51c. With this enforced breakup of the mass flow and the equally enforced residence time of the mixed material in the individual mixing chambers 51c, a high mixing quality is achieved.

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

[0099] The insulation board pressing device 10 ( Fig. 1 , 14-16 ) 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 conveyor channel 9 onto the conveyor belt 69. For this purpose, a channel outlet end of the conveyor channel 9 is arranged above the throwing device 68, so that the straw 22 falls from the conveyor channel 9 into the throwing device 68.

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

[0102] The collecting container 75 is mounted in particular on the base frame 74. In addition, the collecting container 75 has a curved container wall 78a and two adjoining container side walls 78b. The two container side walls 78b are arranged opposite one another as viewed in the direction of the blade rotation axis 76a. And 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 collecting container 75 is open at the top and has a container opening 75a. The collecting container 75 is thus designed as a collecting tray. The two container side walls 78b and the curved container wall 78a surround a container interior 75b.

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

[0104] The blade 76 has a preferably hollow-cylindrical blade shaft 80 and a single blade 81. However, multiple blades 81 may also be present, although a single blade is preferred. The blade shaft 80 is rotationally symmetrical to the blade rotation axis 76a. The blade 81 protrudes radially from the blade shaft 80 relative to the blade rotation axis 76a.

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

[0106] During rotation, the scoop 76 rotates partially inside the collecting container 75 and partially outside the collecting container 75. It is dimensioned such that it is slightly spaced from the curved container wall 78a and the two container side walls 78b. The scoop 76 thus removes the straw 22 located in the container interior 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. In addition, there are side walls 83, particularly vertical ones, on both sides of the conveyor belt 69. These are also mounted on the base frame 74. The two side walls are located 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 already explained, the straw 22 falls from the conveyor channel 9 into the throwing device 68. In particular, it falls into the collecting container 75 and onto the rotating blade 81. As a result, the straw 22 is captured by the blade 81 and thrown parabolically onto the conveyor belt 69. There, it deposits, in particular, according to a Gaussian normal distribution. This results in a uniformly high, 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 converts the individual straw portions emerging from the mixing device 8 into a uniform mass flow.

[0110] The constant density distribution transverse to the conveying direction 82 is achieved in particular via the two side walls 83. The straws that would otherwise be deposited in the outer edge area are collected by the side walls 83 and "added" to the flatter edge area of ​​the mixed material, resulting in a homogeneous density distribution across the cross-section.

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

[0112] The compaction and activation device 70 has a rotating 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. Thus, a hopper is formed between the press belt 85 and the conveyor belt 69, tapering in the conveying direction 82, in which the straw layer is increasingly compacted into a continuous straw strand or a continuous straw web. Furthermore, the straw layer is drawn into the hopper 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 above 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 a homogeneous application of steam to the straw strand and a 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] In addition, the conveyor belt 69 and the press belt 85 are preferably made of plastic, preferably polypropylene. This prevents the binding agent 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 designed as a perforated belt. This is advantageous for higher board densities.

[0116] After the compaction and activation device 70, the compacted straw strand is conveyed into the drying device 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 that activates the binding agent. This leads to reduced strength and binding capacity of the binding agent. To achieve sufficient strength for further processing, especially cutting, in a reasonable time, the straw strand is dried.

[0118] For this purpose, the drying device 72 is preferably designed as a drying channel.

[0119] In the drying device 72, the straw strand is exposed to hot air for drying in alternating directions, preferably first from above, then from below, and then again from above, as viewed in the conveying direction 82. This allows for uniform drying across the cross-section of the straw strand. The hot air provided preferably 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 in order to further improve the flow of hot air through the straw strand in a vertical direction.

[0121] The drying device 72 also preferably has a plurality of circulating 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 device 72, the dried straw strand is conveyed into the cutting device 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 straw insulation boards 12 produced have a low density and therefore good thermal insulation properties.

[0125] Preferably, the straw insulation boards 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, paragraph 4.2.1.

[0126] In addition, the straw insulation boards 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 plasterboards or load distribution boards or impact sound boards or merely for thermal insulation, in particular in a thermal insulation composite system.

[0128] The device 1 according to the invention serves according to a further embodiment of the invention ( Fig. 2 , 18 , 19 ) for the production of dense straw panels 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 pressing device 14 has a receiving device 87, a press 88 and preferably a trimming device 89 arranged downstream of one another in the conveying direction 82.

[0132] The receiving device 87 has a drivable receiving conveyor belt 90, two boundary walls 91 arranged spaced apart from one another in the 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 limit the receiving conveyor belt 90.

[0134] The straw 22 coming from the mixing device 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 device 8 and allowing the straw 22 to fall directly from the mixing device 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 means, e.g. a conveyor belt or a conveyor channel.

[0136] Figure 19 shows preferred further conveying options. Accordingly, the device 1 has, downstream of the mixing device 8, another vibrating trough 84, an adjoining radial fan 93, an adjoining conveying channel 97, and an adjoining cyclone separator 98, which preferably has a rotary valve 99 at its lower end. The vibrating trough 84 is designed in particular analogously to the first vibrating trough 5. The radial fan 93 and the conveying channel 97 have the advantage that the mixing quality is maintained through 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 crosswise arrangement, to the receiving conveyor belt 90. For this purpose, the cyclone separator 98 is preferably movable on a portal in two mutually perpendicular horizontal directions, with 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 applying the straw 22.

[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. For this purpose, the distribution device 92 preferably has a portal with distribution arms that can be moved back and forth in two mutually perpendicular, horizontal directions.

[0139] As soon as 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, circulating press belt, preferably with a separating film, as well as two heatable press plates 94 arranged one above the other, 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, on the one hand, 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 press the straw cake 71, the two parallel pressing plates 94 are pressed together, preferably hydraulically. To achieve a defined distance and thus a defined thickness of the straw plate 13 to be produced, the two pressing surfaces 94a of the two pressing plates 94 are preferably kept apart by spacer strips at the edge of the pressing surfaces 94a.

[0142] During pressing, the press belt is not driven and is arranged 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 binding agent, and the lower heated press plate 94.

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

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

[0145] The produced straw panels 13 are then removed from the trimming device 89.

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

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

[0148] Due to the high temperature, the heat input through contact heat, and the lower binder content, the produced straw panels 13 achieve very good surface strength and dimensional stability upon leaving the press 88. There is no need for subsequent drying to maintain the shape, as is preferably the case with the straw insulation panels 12. The residual moisture content essentially adjusts to the ambient humidity within one day.

[0149] It is also within the scope of the invention to produce straw insulation boards 12 by means of the device 1, which has the pressing device 14.

[0150] Figure 20 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 for the production of dense straw panels 13 or straw insulation panels 12.

[0151] The device 1 comprises, arranged downstream of one another, the straw bale breaking device 2, the conveying channel 3, a homogenizing screw 106, a stone separator 107, a straw witch 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 binding agent 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 (not shown) instead of the pressing device 14.

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

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

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

[0156] The stone separator 107 ( Fig. 20 ) is preferably a riser pipe sifter. The stone separator 107 preferably has an upright, preferably vertical, separator pipe 120, which is open at the bottom and suspended. The separator pipe 120 also has a lateral opening 120a at the bottom, into which the straw 22 is conveyed by the homogenization screw conveyor 119. A lower opening 120b of the separator pipe 120 floats above a cone 121 and is spaced from it, the cone 121 and the separator pipe 120 being coaxial with one another. An air gap is present between the cone 121 and the separator pipe 120.

[0157] The conveying air required to transport the straw 22 through the stone separator 107 is extracted by the blower 115 downstream of the stone separator 107. Both the air volume and the flow velocity of the conveying air can be varied by adjusting the size of the air gap. The conveying air pulls the conveyed straw 22 upward. Other particles that have a different mass or density than the straw cannot be transported upward by the conveying air flow against gravity and fall downward out of the separator pipe 120.

[0158] By means of the stone separator 107, the straw 22 can 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 during the further production 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 manner in the previously described devices 1.

[0160] As already explained, the straw 22 is conveyed from the stone separator 107 into the straw cutter 108. The straw cutter 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 cutter has rotating blades in a known manner. At least some of the straw stalks of the straw 22 are also spliced.

[0161] The Straw Witch 108 makes the straw 22 more homogeneous and a more precisely defined raw material. This improves the board quality, regardless of the quality of the straw cut delivered. The cut straw 22 also has better air flow and mixability, as it becomes more pourable.

[0162] Another particular advantage is that the binding agent adheres better to the straws, as the spreading process allows the inside of the straws to be wetted as well. The wettable surface is thus increased.

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

[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 manner in the previously described devices 1.

[0166] From the straw hopper 108, the shredded straw 22 is conveyed to the cyclone separator 111 via the conveyor line 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 to weigh 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 trough 122 has two trough end walls 122a, two trough side walls 122b, a trough lid 122c, and a trough bottom wall 122d. The trough bottom wall 122d is preferably formed in two parts and has two bottom flaps 125, each pivotably mounted on one of the trough side walls 122b. In particular, the two trough bottom parts 125 are pivotable such that they can pivot or fold away to the side, forming a trough bottom opening between them through which the straw 22 can fall out of the trough 122. To pivot the two bottom flaps 125, the trough 122 also has corresponding, preferably electric or pneumatic, drive means, preferably pneumatic linear cylinders. Electric and pneumatic pivot drives 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 gate valve or closing slide 127. The closing slide 127 can be moved back and forth parallel to the tank lid 122c from a position closing the filling opening 126 to a position exposing the filling opening 126. To pivot the closing slide 127, the weighing device 112 also has corresponding, preferably electric or pneumatic, drive means, preferably pneumatic linear cylinders. Furthermore, the closing slide 127 is mounted on the frame 123 independently of the tank 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 hydrated lime is also added in the weighing device 112. For this purpose, the tank lid 122c has a lime inlet opening.

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

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

[0176] In the release position, the slide base plate 127a is not vertically aligned with the filling opening 126. As soon as the desired filling 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 closed position, the slide base plate 127a is vertically aligned with the filling opening 126 and closes it off. Furthermore, the two boundary walls 128 and the two slide side walls 127b, together with the slide base plate 127a, form an upwardly open collecting container 129 for the straw 22 that 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 amount of straw. This 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 aside 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 one. Thus, the rotational speeds and the applied mixing energy can be precisely controlled and adapted to the material being mixed.

[0181] The mixing trough 130 has two opposing trough end walls 130a, two trough side walls 130b, and one trough bottom wall. The two supporting side walls 130b converge toward each other in the direction of the trough bottom wall, so that the mixing trough 130 tapers downwards.

[0182] At the top, the mixer trough 130 is sealed dust-tight by the weighing device 112. A trough lid is therefore preferably not present.

[0183] This ensures that there is sufficient space for the straw 22 to expand. It was discovered within the scope of the invention that a tubular mixer chamber leads to blockages during the mixing process. It is clearly important that the straw 22 can expand upwards during the mixing process and cannot be compacted by the mixer screws 131; 132 due to a limiting lid surface. Thus, the straw 22 does not touch the trough bottom wall 122d 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 blade or a screw thread 131c; 132c.

[0185] The screw flight 131c of the first, particularly lower, mixing screw 131 is formed from two opposing flight sections 135a;b. The two flight sections 135a;b have an opposing pitch such that the lower mixing screw 131 conveys the material to be mixed toward the center of the mixer trough 130 or 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, preferably electric or pneumatic, drive means, preferably pneumatic linear cylinders.

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

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

[0189] Since the lower mixing screw 131 conveys toward the center and the upper mixing screw 132 conveys away from the center, two essentially circular mass flows are formed, which are conveyed toward the center in the lower area and are pulled apart again in the upper area. In doing so, they are continuously divided and reunited, which is a particularly preferred feature of the mixing process.

[0190] Furthermore, the second, particularly upper, mixing screw 132 has a plurality of prongs 139 that project outward from the screw flight 132c in the radial direction relative to the screw rotation axis 132a. In particular, they project from an outer edge 140 of the screw flight 132c.

[0191] The prongs 139 are used to break up any conglomerates or accumulations during the mixing process and to loosen the mix in general.

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

[0193] In addition, the prongs 139 preferably have a height of 20 mm to 60 mm, preferably 30 mm to 40 mm. The height of the prongs corresponds to the distance of the prong tip 139c from the outer edge 140 of the wing.

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

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

[0196] As soon as the mixing process is complete, as already explained, the trough outlet opening 136 is opened, and the lower mixing screw 131, with the discharge plate 141, conveys the finished mixed material radially out of the screw mixer 113. This occurs successively and evenly. Furthermore, the discharge speed can be determined by the speed of the mixing screws 131; 132. This uniform discharge forms the basis for further conveying of the mixed material with conveying air.

[0197] From the screw mixer 113, straw 22 mixed with binding agent is conveyed to the distribution device 92 by means of the conveyor line 116.

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

[0199] In addition, 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 3.3 to 3.8 N / mm 2< , according to DIN EN ISO 29469:2023-02.

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

[0202] As already explained, the uniform mixing of the straw 22 with the binder mixture is not easy because the straw 22 tends to form accumulations of material and clump together.

[0203] The mixer forks 62 can easily break up these material accumulations thanks to the spring-loaded tines 66 and force peaks that can lead to damage are avoided.

[0204] Furthermore, the inventive division of the mixing chamber 57a into the individual vertically stacked mixing chambers 51c and the retractable and extendable intermediate floor sections 60 regulate the further conveyance of the straw 22. This prevents overfilling of the individual mixing chambers 51c. And with this enforced division 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 to the conveyor belt 69 of the pressing device 10 is important for the properties of the subsequent straw insulation boards 12. In particular, the laying of the individual straw stalks influences the density distribution as well as the mechanical properties of the straw insulation board 12. The problem here is that the straw-binder mixture is neither pourable nor free-flowing. It is therefore advantageous if it is actively broken down and laid down again in order to avoid local density differences in the straw insulation board 12. Within the scope of the invention, it was discovered that a loose, undirected laying of the straw stalks is advantageous, so that the subsequent compaction results in the best possible interlocking of the straw stalks with one another.This prevents the formation of separating layers caused by aligned straws, which negatively impact the mechanical properties of the straw insulation boards 12. In particular, alignment or layering of the straws should be avoided, as this could lead to predetermined breaking 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 scoop 76 simultaneously breaks up nests and clumps 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 parabolically onto the moving conveyor belt 69, where it deposits 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 converts the individual straw portions emerging 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 by means of steam is advantageous.

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

[0211] The use of steam for heating, however, enables efficient and very rapid heating of the entire straw layer through various physical effects. The steam condenses and transfers the released condensation energy to the binding agent, thereby immediately bringing the binding agent to the activation temperature.

[0212] The phase transition from steam to liquid also creates local negative pressures, allowing additional steam to flow in, thus ensuring complete, flawless heating of the entire straw layer. This reliably activates the binding agent in every area. With the introduction of steam, the straws also become temporarily soft, and their resilience decreases. This reversible change in the straw 22 enables faster shaping and demolding of the pressed straw layer strand without the lengthy calibration steps that would otherwise be necessary until the binding agent 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 more 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 earth-moist. The straw 22 is only wetted with the binding agent, and the straws are only bonded together at the contact points.

[0215] It is also within the scope of the invention 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 it is preferred the other way around.

[0216] It is of course also possible for the device 1 to have several plate pressing devices 10;14 operated in parallel.

[0217] The screw mixer, as described above, is particularly advantageous and the preferred mixing device. The rapid movement of the mix through the mixing screws in the screw mixer also swirls air into the mix. The teeth on the upper mixing screw, in particular, contribute significantly to this. This changes the properties of the straw, which would otherwise tend to conglomerate and clump, and causes it to behave like a fluid. This allows the mix to flow in the streams described above within the screw mixer, achieving excellent mixing quality while maintaining a very robust mixer design. The solid screw construction is resistant to blockages and damage caused by compacted fiber-binder nests. 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 both very low-maintenance and requires minimal maintenance. The encapsulated mixing chamber is sealed and minimizes dust emissions.

[0218] Within the scope of the invention, it is also self-evident that the different components of the various embodiments of the devices 1 are combined with one another.

[0219] For example, the stack mixer 51 and the screw mixer 113 can be interchanged.

[0220] This also applies to the vibrating chute 5 and the homogenizing conveyor screw 119. It is only important that a homogenizing device is present which homogenizes the straw 22 so that it becomes suitable for air conveyance.

[0221] In addition, the stone separator 107 and / or the straw witch 108 can of course also be integrated into the devices 1 according to Figure 1 and 2 Both the stone separator 107 and the straw separator 108 must always be arranged upstream of the mixing device 8.

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

[0223] And in particular, the dosing 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 from the straw 22 again due to the air conveyance.

[0224] The hydrated lime feed device 6 can also be used very advantageously in the production of other fiberboards or chipboards for adding hydrated lime to the fibers, in particular the straw, or the chips.

Claims

1. Lime hydrate feeding device (6) for feeding hydrated lime in the production of fibreboard or chipboard, preferably straw boards, characterized in that the hydrated lime supply device (6) has a storage container (37) for receiving the hydrated lime, preferably a mixer shaft (39) with at least one mixer rod (40), as well as a rotary valve (41) with a blow-out device (46) for blowing out the hydrated lime from the rotary valve (41) and a drive motor (38) for driving the rotary valve (41).

2. Lime hydrate supply device (6) according to claim 1, characterized in thata) the mixer shaft (39) is connected to the drive motor (38) so as to be rotatable about a mixer shaft rotation axis (39a) and / or is arranged above the rotary valve (41), and / or b) the rotary valve (41) has a rotary valve (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 mixer shaft (39), wherein the rotary valve (42) preferably has a rotary valve 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 groove-like and preferably have a longitudinal extension parallel to the rotary valve axis (42a), and wherein a cell wall of the cells (44) preferably has a circular arc-shaped, preferably semicircular cross-section, wherein the cross-section preferably extends over a maximum of 180°.

3. Lime hydrate supply device (6) according to claim 2, characterized in that the lock housing (43) has a blow-out channel (45) in the region of the lock outlet (41b), wherein the blow-out channel (45) has 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) has a compressed air source (47) for the in particular continuous provision of compressed air, which is connected to the channel inlet end (45a), and wherein the blow-out channel (45) is designed such that it is in fluid communication with the cell (44) located in the region of the lock outlet (41b), wherein the blow-out channel (45) preferably has a U-shaped course.

4. Device (1) for producing straw slabs (12; 13) comprising a) a straw bale breaking device (2) for breaking up 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 slab 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 slabs (12) or a discontinuous slab pressing device (14) for pressing the straw (22) mixed with the binder mixture into individual straw slabs (13) and curing the binder mixture, e) a control device (11) for controlling the production process, characterized in thatthe mixing device (8) f1) comprises a screw mixer (113) with at least two mixing screws (131; 132) arranged one above the other, or f2) a multi-level mixer (51) with several mixing chambers (51c) arranged one above the other, preferably 3 to 10, more preferably 4 to 5.

5. Device according to claim 4, characterized in that the screw mixer (113) has a mixing trough (130) which has at least two mixing screws (131; 132) arranged one above the other and at least one, preferably two, mixing screw drive motors (133; 134).

6. Device according to claim 4 or 5, characterized in thatthe two mixing screws (131; 132) each have a screw axis of rotation (131a; 132a), a screw shaft (131b; 132b) and a screw wing (131c; 132c), wherein preferably the screw wing (131c) of the lower mixing screw (131) has two wing sections (135a; b) which have an opposing pitch such that the lower mixing screw (131) conveys the material to be mixed in a direction parallel to the screw axis of rotation (131a) towards the center of the mixer trough (130).

7. Device according to claim 6, characterized in that the screw flight (132c) of the upper mixing screw (132) has two mutually oppositely rotating flight sections (138a;b) which have an oppositely rotating pitch such that the upper mixing screw (132) conveys the material to be mixed away from the center of the mixer trough (130) in a direction parallel to the screw rotation axis (132a).

8. Device according to claim 6 or 7, characterized in thatthe upper mixing screw (132) has a plurality of prongs (139) which project outwards from the screw wing (132c) in the radial direction relative to the screw rotation axis (132a), preferably from an outer edge (140) of the screw wing (132c).

9. Device according to claim 8, characterized in that a) the prongs (139) have two prong edges (139a;b) merging into one another and a prong tip (139c), wherein the prong edges (139a;b) preferably enclose an obtuse angle with one another and / or b) the prongs (139) are spaced apart from one another by 20° to 90°, preferably 30° to 45°, as seen in a circumferential direction with respect to the screw rotation axis (132a), and / or c) the prongs (139) have a height of 20 mm to 60 mm, preferably 30 mm to 40 mm.

10. Device according to one of claims 6 to 9, characterized in thatthe mixing trough (130) has a trough outlet opening (136) in a region where the two counter-rotating wing sections (135a;b) of the lower mixing screw (131) meet, which can be closed and opened by means of a closing slide (137), and preferably the lower mixing screw (131) has a radially arranged discharge plate (141) in the middle of the mixing screw (131), where the two counter-rotating wing sections (135a;b) meet.

11. Device according to one of claims 4 to 10, characterized in that the weighing device (112) is arranged, preferably directly, in front of the mixing device (8), in particular in front of the screw mixer (113) or the multi-level mixer (51).

12. Device according to claim 4 or 11, characterized in thatthe mixing chambers (51c) of the multi-level mixer (51) are separated from one another by, in particular horizontal, intermediate floors (63) which can be opened at least partially towards the mixing chamber (51c) located underneath, wherein the intermediate floors (63) preferably each have at least one movable intermediate floor part (60) which can be moved out of and into a mixer interior (57a) by means of drive means.

13. Device according to claim 12, characterized in thata) an intermediate floor (63) has two movable intermediate floor parts (60) which can be pivoted out of the mixer interior (57a) and into it by means of drive means, wherein the two movable intermediate floor parts (60) can preferably be moved towards and away from each other in a scissor-like manner, and / or b) the intermediate floors (63) each have at least one fixed or immovable intermediate floor part (59), and / or c) the intermediate floors (63) can each be opened independently of each other, preferably the movable intermediate floor parts (60) of the individual intermediate floors (63) can each be moved independently of each other.

14. Device according to one of claims 4, 12 or 13, characterized in thatthe multi-level mixer (51) has at least one mixer fork (62) for each mixing chamber (51c), which mixer fork has at least two tines (66), wherein the mixer fork (62) is fixedly fastened at one end to a mixer shaft (58) which can be driven rotatably about a mixer shaft axis of rotation (58a) and projects therefrom in the radial direction with respect to the mixer shaft axis of rotation (58a), wherein the tines (66) of a mixer fork (62) are preferably arranged one above the other and in alignment with one another in the vertical direction, wherein the tines (66) preferably have a non-deflected starting position in which they preferably extend in the radial direction with respect to the mixer shaft axis of rotation (58a), and can be deflected from the starting position against spring force about a preferably vertical tine axis of rotation (66a) in two opposite directions.

15. Device according to one of the preceding claims 4, 11 to 14, characterized in thatthe multi-level mixer (51) has 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 floor part (59) of the intermediate floor (63) of the uppermost mixing chamber (51c).

16. Device according to one of claims 4 to 15, characterized in thata) the device (1) has a hydrated lime feed device (6) for feeding hydrated lime separately from the binder mixture according to one of claims 1 to 3, and / or b) the device (1) has at least one radial fan (36; 93; 109; 115) and a conveying channel (7; 110; 116) for conveying the straw (22) by means of conveying air, and / or c) the device (1) has 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 upstream of the mixing device (8) and preferably upstream of the weighing device (112), and / or d) the device (1) has a straw cutter (108) for at least partially splitting the straw stalks and for comminuting them to a predetermined stalk length, preferably to a stalk length from 10 mm to 60 mm, preferably 20 mm to 40 mm,wherein the straw spiral (108) is arranged upstream of the mixing device (8) and preferably upstream of the weighing device (112), wherein the straw spiral (108) is also preferably arranged downstream of the stone separator (107), and / or e) the device (1) has a homogenizing device for homogenizing the straw (22), which is preferably arranged directly downstream of the straw bale breaking device (2), wherein the homogenizing device is preferably a homogenizing screw (106) having a collecting container (118) and a homogenizing conveyor screw (119) connected thereto, or a vibrating trough (5).

17. Device according to one of claims 4 to 16, characterized in thatthe pressing device (14) has a receiving device (87), a press (88) and preferably a trimming device (89) arranged downstream of one another in the conveying direction (82), wherein the receiving device (87) preferably has a drivable receiving conveyor belt (90), two boundary walls (91) arranged spaced apart from one another in the horizontal direction and a distribution device (92).

18. Device according to claim 17, characterized in that a) the pressing device (14) has means for applying the straw (22) in a meandering manner, preferably in a cross-connection, to a base, preferably to the receiving conveyor belt (90), and / or b) the press (88) has two heatable pressing 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, in particular according to one of claims 4 to 16, for producing straw insulation boards (12) 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 binder mixture, d) a continuous insulation board 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 boards (12), e) a control device (11) for controlling the production process, characterized in thatthe continuous insulation board pressing device (10) comprises a conveyor belt (69), a throwing device (68) for throwing the straw (22) onto the conveyor belt (69), a compacting and binding agent activation device (70) for compacting the straw (22) mixed with the binding agent mixture into a continuous straw strand and for curing the binding agent 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 boards (12), wherein the throwing device (68) preferably comprises a collecting container (75), a blade (76) rotatably driven about a blade rotation axis (76a), and a drive motor (77) for driving the blade (76), wherein the blade (76) preferably comprises a blade shaft (80), preferably a hollow-cylindrical blade, rotationally symmetrical to the blade rotation axis (76a), and a single blade blade (81),which protrudes from the blade shaft (80) in the radial direction relative to the blade rotation axis (76a).

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

21. Device according to claim 19 or 20, characterized in thatthe continuous insulation board pressing device (10) has, on both sides of the conveyor belt (69), in particular vertical, side walls (83) which are opposite one another in a direction parallel to the blade rotation axis (76a) and preferably extend as far as the throwing device (68) and shield it laterally.

22. A method for producing straw panels (12; 13) by means of a device (1) according to one of claims 4 to 21, comprising 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 to form a continuous straw strand, hardening the binder mixture and cutting the straw strand into individual straw panels (12) or, with simultaneous hardening of the binder mixture, pressing the straw (22) mixed with the binder mixture to form individual straw panels (13).

23. Method according to claim 22, characterized in thata) the curing of the binder mixture takes place by subjecting the binder mixture to temperature, and / or b) the straw (22) is crushed and preferably spliced ​​before mixing with the binder mixture.