EP2922670B1 - Fall duct arrangement with a dual cleaning device, in particular for a device for gluing particles in the course of producing material boards - Google Patents

Description

The present invention relates to a chute arrangement according to the preamble of claim 1.

The production of material plates from, for example, chips or medium-density fibers or other free-flowing materials are now automated processes and have already been used in many countries for many years. As is known, the compression of processed chips or fibers takes place either clock-bound or continuously. In addition to the many plant components before and after the press, the production of a spreading material mat by means of spreading machines plays an outstanding role, since the quality of the produced spreading material mat is an important factor in addition to the quality of the raw materials. The urge to produce cost-effective material plates from natural raw materials and artificially produced binders forces producers to develop more and more efficient processes. Special emphasis is on low downtime and low wear.

The present development relates to the field of gluing the particles with a binder. Basically, the term binder is understood to mean a so-called adhesive liquor which consists of an adhesive in its main component. Depending on requirements, in addition emulsion, hardener, formaldehyde scavengers, dyes, insect repellent and antifungal agents and other additives are added. It is also common to use the adhesive without additives.

The following are suitable as binders without any claim to completeness: isocyanates, MDI, melamine urea formaldehyde (MUF), urea formaldehyde (UF), MUPF or PF.

The gluing is typically carried out such that the grit or the particles are introduced by means of a metering device in a chute and by means of nozzles which are arranged in the chute or this upstream, is acted upon or become the binder. The glued spreading material is usually treated in a downstream of the chute drum with rotating conveyor tools (mechanical mixer) and / or glued on and then sprinkled to a grit mat and then promptly, before curing a glue, pressed. Alternatively, the grit may be introduced directly into a spreader without passing through a mechanical mixer to sprinkle the grit mat and then crimp.

Such a device is for example from the document DE 10 2010 064 339 A1 known.

Here, there is the problem that binders and particles glued to the binder may accumulate on the inner wall of the chute so that the chute tends to become soiled. This makes it necessary to clean the chute regularly. For this, the plant usually has to be shut down, which brings with it a corresponding loss of production.

In addition, there is the possibility that solid deposits of not negligible size may form on the inner wall of the chute over time. If such deposits dissolve and fall into the mixer, it is not ensured that such lumps of solid deposits in the mixer are crushed and dissolved. It may therefore be in the paste of glued particles leaving the mixer, further solid lumps, which in the further course of the production of material plates can lead to impairment of product quality and / or damage to the presses.

In order to prevent or reduce the soiling of the inner walls of a chute and the formation of solid deposits on these, is in the document WO 2011/134844 A1 proposed to cover the inner walls of the chute with doctor blades or spatulas. The spatulas are firmly attached to a support structure consisting of an upper ring and a lower ring. The upper ring is connected to a toothed ring with internal teeth, which is driven by a pinion and a motor. Driven so driven the doctor blades in a rotational movement about a vertical axis on the inner wall of the rotationally symmetrical chute.

Although it can be prevented in this way that form larger deposits on the inner wall of the chute, but at the price that with the Scraper blades new elements and surfaces are introduced into the chute, which in turn pollute and on which solid deposits can form. Thus, it can happen, especially in large plants, that can form on the doctor blades caking, which weigh up to 50 kg and can fall off in a lump, which can lead to damage of the mixer and / or the subsequent machines.

In the document WO 2011/134844 A1 Therefore, it is proposed to cool the doctor blades to a temperature which is below the condensation point of the humidity, so that a condensate film is formed on the surfaces, which is intended to reduce the adhesiveness of the injected chemical components, in particular of thermosetting adhesives.

Depending on the requirements of a particular application, in particular depending on which binder and / or which additives are used, it may be undesirable that condenses moisture in the chute. In this case, the document WO 2011/134844 A1 proposed doctor blade cooling can not be used effectively.

In other cases, depending on the binder used and / or the additives used, the effect of a condensate film is not or only slightly, so that adhesion is only slightly reduced, or even reversed, if certain binders or additives in moisture and / or at reduced temperatures show an increased tendency to stick and / or clump together. Even in these cases, a use of the document WO 2011/134844 A1 proposed Schaberklingenkühlung not be displayed.

In addition, it is for the realization of the document WO 2011/134844 A1 proposed Schaberklingenkühlung required to provide appropriate supply lines and discharges for a cooling fluid having a sufficient delivery capacity. In order to supply the walls of a rotating chute and / or rotary doctor blades with the cooling fluid, it is also necessary that appropriate fluid-carrying coupling means are provided, which is a transfer of cooling fluid from a stationary part of the system to the rotating chute walls and / or the rotating doctor blades allow. The mechanical structures required for this can be a great effort and it may be difficult to achieve a permanently effective seal.

It is therefore an object of the present invention to provide a chute assembly which can effectively prevent the formation of solid buildup within a chute.

It is therefore an object of the present invention to provide a chute assembly which is applicable to chutes of various shapes.

Further, it is an object of the present invention to provide a chute assembly that can be easily integrated into already built facilities.

These and other objects of the invention are achieved by a chute assembly according to claim 1. Further preferred embodiments are set forth in the dependent claims.

As a solution, a chute arrangement is specified, in particular for a device for gluing particles which at least partially consist of fibers and / or chips suitable for producing material plates, wherein the chute arrangement has a chute which has an inlet for feeding the particles and an outlet for dispensing the particles, and a spatula arranged to move relative to an inner wall of the chute to clean the inner wall. The chute arrangement further has at least one flexible stripping element for cleaning the at least one spatula, wherein the flexible stripping element is stretched in the travel path of the at least one spatula over the inner wall; and driving means are further provided which are adapted to move the flexible wiper element in a movement in a direction of the longitudinal extension of the flexible wiper element.

While the scraper allows to keep the inside wall of the chute clean, the flexible scraper allows the scraper to be cleaned. By the flexible stripping element is set in motion, the flexible Stripping element sections are moved out of the interior of the chute, so that the previously located inside the chute section of the flexible stripping element is accessible for cleaning. It can thus be effectively ensured that no solid deposits form in the chute.

The at least one flexible stripping element can be designed as an endless stripping element.

The at least one endless stripping element can preferably be arranged by means of deflecting means so that it encloses a wall element of the chute, which has the inner wall.

The at least one endless stripping element can furthermore preferably be arranged such that it is arranged running in the region of the inner wall within the chute.

The chute may in particular further comprise two winding devices, wherein the flexible stripping element is connected to the winding devices in order to be wound and unwound by the winding devices can.

The drive means may preferably be arranged to offset the at least one flexible stripping element into a circumferential movement and / or a reciprocating movement in the direction of the longitudinal extent of the stripping element.

The at least one flexible stripping element may be arranged adjacent to the inner wall of the chute in a substantially vertical direction and / or arranged to extend in a corresponding manner to a shape of the chute in the vertical direction.

Preferably, further clamping means are provided which are adapted to keep the at least one flexible stripping element under tension.

Preferably, a cleaning device may further be provided, which is arranged such that the at least one stripping element is guided past the cleaning device or running through the cleaning device.

The cleaning device can be embodied as a fluid bath, a brush, a wiper edge, or a stripping cylinder.

The spatula may be formed as a scraper, as a spatula blade, as a spatula, or as a rod.

The at least one flexible stripping element can be designed as a rope, in particular a wire rope, as a wire, as a band or as a chain.

Preferably, the chute is tapered in the direction of the particle from top to bottom in cross section.

The chute can be cylindrical or conical.

The chute can have a substantially concave shape.

The at least one inner wall, preferably all inner walls of the chute can be stripped at least once in two minutes, in particular once a minute.

Preferably, a tempering device may further be provided for tempering the inner wall to a temperature which is below a threshold for the curing of the binder, preferably below 70 ° C.

As a further solution is a device for the gluing of particles, which consist at least partially of suitable for the production of material plates fibers and / or chips, wherein the device comprises a chute assembly.

The apparatus may further comprise a supply means for feeding the particles and a plurality of nozzles for discharging a binder, the nozzles being in an area inside the chute and / or above an inlet opening of the chute.

More preferably, the device has a mixing device downstream of the chute arrangement.

Fig. 1

zeigt schematisch eine Vorrichtung zur Beleimung von Partikeln;

Fig. 2A

zeigt in einer schematischen Draufsicht eine Fallschachtanordnung gemäß einer ersten Ausführungsform der vorliegenden Erfindung;

Fig. 2B

stellt eine schematische Draufsicht der Fallschachtanordnung der Fig. 2A dar;

Fig. 3A bis 3D

zeigen in einer schematischen Querschnittsansicht das Abstreifen eines Spachtels durch ein flexibles Abstreifelement während der Bewegung des Spachtels;

Fig. 4

zeigt in einer schematischen seitlichen Querschittsansicht eine Fallschachtanordnung gemäß einer zweiten Ausführungsform der vorliegenden Erfindung;

Fig. 5

zeigt in einer schematischen seitlichen Querschittsansicht eine Fallschachtanordnung gemäß einer dritten Ausführungsform der vorliegenden Erfindung;

Fig. 6

zeigt in einer schematischen seitlichen Querschittsansicht eine Fallschachtanordnung gemäß einer vierten Ausführungsform der vorliegenden Erfindung;

Fig. 7A

zeigt in einer schematischen seitlichen Querschnittsansicht eine Fallschachtanordnung gemäß einer fünften Ausführungsform der vorliegenden Erfindung; und

Fig. 7B

stellt eine schematische Draufsicht der Fallschachtanordnung der Fig. 7A dar.

Embodiments of the invention are illustrated below with reference to the drawings:

Fig. 1

shows schematically a device for the gluing of particles;

Fig. 2A

shows a schematic plan view of a chute arrangement according to a first embodiment of the present invention;

Fig. 2B

FIG. 12 is a schematic plan view of the chute assembly of FIG Fig. 2A group;

Fig. 3A to 3D

show in a schematic cross-sectional view the stripping of a spatula by a flexible scraper element during the movement of the spatula;

Fig. 4

shows in a schematic lateral cross-sectional view of a chute assembly according to a second embodiment of the present invention;

Fig. 5

shows in a schematic lateral cross-sectional view of a chute assembly according to a third embodiment of the present invention;

Fig. 6

shows in a schematic lateral cross-sectional view of a chute assembly according to a fourth embodiment of the present invention;

Fig. 7A

shows in a schematic side cross-sectional view of a chute assembly according to a fifth embodiment of the present invention; and

Fig. 7B

FIG. 12 is a schematic plan view of the chute assembly of FIG Fig. 7A represents.

In FIG. 1 is a schematic view of a device for the gluing of particles beginning with the metering device 2 and ending with a mixing device 7 in a general representation. In between, a chute 3 and a chute arrangement 10 to be described in more detail below are arranged. The particles are thereby introduced as a particle stream into the metering device 2, usually from a particle bunker by means of discharge devices, weighed there and introduced into the chute 3 for metering via a standard belt control (not shown).

There, the particle stream or the particles 1 impinges on an optional dissolving device 4 and is there dissolved to a particle curtain 5 and / or divided.

The optional opening device 4 may in particular have rake and / or baffle plates, spoke rollers and / or opening rollers, preferably designed as spiked rollers. The resolving device 4 is therefore optional because under certain circumstances, i.d.R. Depending on the nature of the particles 1, already the metering device 2 can generate a sufficiently useful particle curtain 5.

The particle curtain 5 or the particles 1 are then sprayed by means of suitable nozzles 6 with a binder and glued.

In the course of the particle curtain 5 falls through the chute assembly 10 and then passes into the chute assembly 10 downstream mixing device 7, in which by means of a rotating shaft driven by a mixing shaft 9 mixing the glued particles 8 again mechanically and finally spend as a mixed particle flow (discharge arrow) , Depending on the method steps, the mixing device 7 may also be dispensed with here.

The glued particle stream is then stored in a dosing hopper or directly into a spreader to form a grit mat, which can be pressed in a further press in a press to a material plate and / or cured, introduced.

In principle, the chute arrangement 10 should have a sufficient drop height so that the binder can bond sufficiently strongly with the particles and should preferably be formed at least half as long as the chute 3 in the direction of fall.

Like in the FIG. 1 illustrated, the chute 3 and the chute assembly 10 may be provided as separate devices. Alternatively, it is also possible that the chute 3 forms a unit with a chute of the chute assembly 10.

With reference to the FIGS. 2A to 7B Now, various embodiments of a chute assembly (20, 40, 50, 60, 70) will be described, which is used as a chute assembly 10 in the apparatus of FIG. 1 is usable.

A first embodiment of a chute assembly 20 is shown in FIGS FIGS. 2A and 2B shown.

The FIGS. 2A and 2B illustrate a chute assembly 20 with a chute 21. As in FIGS FIGS. 2A and 2B shown, in this embodiment, the chute 21 may be configured rotationally symmetrical, in particular conical, with a wall defining an inner wall 21a.

The chute assembly 20 includes a spatula 27 arranged to move relative to the inner wall 21a of the chute 20. For example, the spatula 27 may be disposed on a support ring device 28, which is preferably arranged at an upper end of the chute 21, ie inlet side. The support ring assembly 28 may be configured rotatable, or may be arranged rotatably supported for example with bearing means 29, so that by means of a drive device, not shown, the spatula 27 can be set in a rotational movement about an axis of rotation of the chute 21. The spatula 27 may be set in motion to strip over the inner wall 21a so that particles 1, sizing agents and / or other adhesions and / or contaminants adhering to the inner wall 21a are scraped off by the spatula 27 and thus the inner wall 21a is cleaned ,

By stripping off the adhesions and / or dirt from the inner wall 21a of the chute 21, it happens that these partially adhere to the filler 27 and contaminate it, in particular on a surface facing the interior of the chute 21. It is therefore further provided a flexible scraper 22, which is stretched in the travel of the spatula 27 over the inner wall 21a of the chute 21, so that when the spatula 27 passes in its movement, the point of the flexible scraper 22, the spatula 27 between the inner wall 21a and the flexible scraper element 27 moves therethrough. The flexible stripping element 22 may preferably be formed as a rope, in particular wire rope, as a wire, as a band or as a chain.
In order to keep the flexible scraper element 22 stretched, clamping means can preferably be provided in addition, which in the FIG. 2A exemplified as a spring 24 and a pinch roller 25 to tension the flexible wiper element 22.

The flexible stripping element 22 can thus strip over the side facing away from the inner wall 21a, or the side of the spatula 27 facing the interior of the chute 21, so that the spatula 27 is stripped and cleaned by the flexible stripping element 22. This is in the FIGS. 3A to 3D which show in a schematic cross-sectional view various consecutive positions of the spatula 27 during the movement for stripping the inner wall 21 a of the chute 21, and show how the spatula 27 moves past the flexible stripping element 22 and is thereby stripped by the flexible stripping element 22 ,

By the flexible wiper 22, therefore, the effect can be achieved, that also the spatula 27 can be cleaned of dirt and / or debris and kept free.

As in the FIGS. 2A and 2B is further shown, the flexible stripping element 22 can be designed endless and can be guided and held over deflecting means 23, such as pulleys, that it surrounds the wall of the chute 21, so that the endless flexible stripping element 22 adjacent both in the chute 21 Inner wall 21a, as well as outside the chute 21 extends.

The deflection roller 23 may be associated with a drive (not shown) in order to set the endless flexible stripping element 22 in the direction of extension in the longitudinal direction of the flexible stripping element 22 in motion via the deflection roller 23. The movement may be an intermittent or continuous circumferential movement of the endless flexible stripping element 22, or an oscillating reciprocation of the endless flexible stripping element 22, or a combination thereof.

The flexible stripping element 22 can thus be moved out of the region of the interior of the chute 21 in sections, so that the flexible stripping element 22 can be cleaned in sections in order to adhesion and / or contamination by particles 1 or binder, which is due to the stripping of the spatula 27 the flexible wiper 22 have deposited, and to clean the flexible wiper 22.

The cleaning of the flexible stripping element 22 can be done manually. Preferably, however, the chute arrangement 20 has a cleaning device 26 for cleaning the flexible stripping element 22. The cleaning device 26 may in particular be arranged such that the flexible stripping element 22 extends past it or through the cleaning device 26.

The cleaning device 26 may be formed, for example, as a brush, scraper blade, or as a scraping edge on which the flexible stripping element 26 is moved past, or as a stripping gap or as a stripping cylinder, through which the flexible stripping element 26 passes. The cleaning device 26 may also be configured as a fluid bath which is filled, for example, with water and / or a cleaning agent and through which the flexible wiping element 26 is guided in order to wash away and detach the sizing agent or particles 1 therefrom. The adhering to the flexible scraper 22 deposits and / or contamination can be removed so definitively from the area of the interior of the chute 21 and do not get into the further process chain.

While in the first embodiment, the chute 21 is shown as a cylindrical or conical chute 21 (see. FIGS. 2A and 2B ), this is not limiting, and other forms may be used.

For example, shows the FIG. 4 a chute assembly 40 according to a second embodiment, wherein the chute 41 has a wall which is arcuately curved, so that the chute 41 tapers in the direction of the particle 1 from top to bottom. Correspondingly, a spatula 47 is provided, which is also configured corresponding arcuately curved to correspond to the arcuate curvature of the inner wall 41. Incidentally, the chute assembly 40 substantially the same elements as the chute assembly 20 of the first embodiment, the description of which is made to the above embodiments.

Due to the curved or concave shape of the chute 41 pointing towards the interior of the chute 41, in which the wall may be cambered in particular, there is the advantageous effect that the flexible scraper element 22 provides a particularly good support against the inner wall 41a of the chute 41 comes to rest and adapts due to its flexibility of the shape of the inner wall 41a. This effect is further enhanced by additional clamping means such as the spring 24 and the pressure roller 25. As a result, a particularly secure cleaning of the spatula 27 can be achieved.

A chute assembly 50 according to a third embodiment is disclosed in U.S. Patent Nos. 4,135,074 FIG. 5 shown. The chute assembly 50 according to the third embodiment differs from the chute assembly 20 according to the first embodiment in that the endless flexible scraper member 52 is guided by a guide roller 53 so that the endless flexible scraper member 52 extends substantially entirely within the chute 51, so that the leading and returning portions of the flexible wiper element 52 are both stretched over the inner wall 51 a of the chute 51. Such a guide of the flexible stripping element 52 has the advantageous effect of a smaller space requirement, since no clearance for the outside of the chute 51 extending portion of the flexible stripping element 52 is required. In addition, the spatula 27 is twice over-coated by the double-extending flexible stripping element 52, resulting in a better cleaning performance. In the FIG. 5 Furthermore, a cleaning device 56 in the form of a scraping edge for stripping the flexible stripping element 52 is shown.

The FIG. 6 shows in a further variant, a chute arrangement 60 according to a fourth embodiment. In this embodiment, the flexible scraper element 62 may be formed as a stripping element of finite length which is attached to two winding devices 63 which can wind and unwind the flexible scraper element 62. By appropriate control of a drive (not shown) of the winding means 63, the flexible stripping element 62 can be displaced in a reciprocating motion in the longitudinal direction. The cleaning device 66 is in the example of the FIG. 6 as a wiping edge against which the flexible wiper element 62 is passed to wipe it off.
A chute assembly 70 according to a sixth embodiment is shown in FIGS FIGS. 7A and 7B shown. As in the FIGS. 7A and 7B shown, the spatula 27 is not attached to a support ring. Instead, two support rods 73 are provided to which the spatula 27 is attached. The support rods 73 are guided through respective openings 72 in the chute 71 and can be so bent and / or designed so resilient that the support rods 71 press the spatula against the inner wall 71 a of the chute 71. By the support rods 73 are moved back or forth, as shown by the arrows in the FIGS. 7A and 7B As shown, the spatula 27 can be moved relative to the inner wall 71a of the chute 71 to scrape and clean the inner wall 71a.

While the invention has been described above by way of example of preferred embodiments, these are not limiting. Thus, various aspects of the various embodiments may be combined or interchanged.

While examples have been given above in which the spatula 27, 47 is moved relative to an inner wall 21a, 41a of the chute 21, 41, this is not limitative and it is also possible to feed the chute 21, 41 itself by suitable drive means move. Thus, for example, the chute 21, 41 be configured rotationally symmetrical and are offset by corresponding drive means in a rotational movement, so that the inner wall 21a, 41a of the chute 21, 41 with respect to the spatula 27, 47 moves. The spatula 27, 47 can be held stationary by appropriate means while the inner wall 21a, 41a moves past the spatula 27, 47. It is also possible to combine a movable spatula 27, 47 with a movable chute 21, 41. It is also possible to move the spatula 27, 47 in different ways. Thus, the spatula 27, 47 as described above in one direction of rotation continuously rotating. However, this is not limitative, and the spatula 27, 47 may also be moved intermittently, and / or may be moved in a forward / backward motion.

Moreover, the present invention is not limited to a single putty 27, 47, and several putties 27, 47 may be used, which are preferably arranged regularly spaced.
Furthermore, the chute arrangement 10, 20, 40, 50, 60, 70 may have a tempering device for tempering one or more inner walls 21a, 41a, 51a, 71a to a temperature which is below a threshold for curing the binder, preferably below 70 ° C.

While in the foregoing case there are described chutes 21, 41, 71 which are made substantially in one piece, this too is not restrictive, and the present invention is also applicable to chute arrangements having chutes made up of a plurality of elements, such that, for example, a plurality of elements each form an inner wall of the chute. (1469) List of Reference Numerals: P1469 1 particle 40 Chute arrangement 2 metering 41 chute 3 chute 41a inner wall 4 dissolver 47 spatula 5 particle curtain 6 jet 50 Chute arrangement 7 mixing device 51 chute 8th Mixing tools 51a inner wall 9 wave 52 stripping element 10 Chute arrangement 53 idler pulley 56 cleaning device 20 Chute arrangement 21 chute 60 Chute arrangement 21a inner wall 62 stripping element 22 stripping element 63 angle facilities 23 deflecting 66 cleaning device 24 feather 25 pinch 70 Chute arrangement 26 cleaning device 71 chute 27 spatula 71a inner wall 28 Support ring means 72 opening 29 Storage facility 73 supporting rod

Claims (17)

1. A drop shaft arrangement (10; 20; 40; 50; 60; 70), in particular for a device for gluing particles (1) which consist at least partly of fibers and/or chips suitable for producing material boards, wherein the drop shaft arrangement (10; 20; 40; 50; 60; 70) comprises:

   a drop shaft (21; 41) having an inlet for feeding the particles (1) and an outlet for discharging the particles (1);

   a scraper (27; 47) arranged to move relative to an inner wall (21a, 41a) of the drop shaft (21; 41) in order to clean the inner wall (21a, 41a),

   characterized in that

   the drop shaft arrangement (10; 20; 40; 50; 60; 70) further comprises at least one flexible stripping element (22; 52; 62) for cleaning the at least one scraper (27; 47),

   wherein the flexible stripping element (22; 52; 62) is tensioned over the inner wall (21a; 41a) in the travel path of the at least one scraper (27; 47);

   and that drive means are further provided which are designed to set in motion the flexible stripping element (22; 52; 62) in a direction of the longitudinal extension of the flexible stripping element (22; 52; 62).
2. Drop shaft arrangement (20; 40; 50) according to claim 1, characterized in that the at least one flexible stripping element (22; 52) is an endless stripping element (22; 52).
3. Drop shaft arrangement (20; 40) according to claim 2, characterized in that the at least one endless stripping element (22) is arranged by means of deflection means, preferably deflection rollers (23), in such a way that it surrounds a wall element of the drop shaft (21; 41) which comprises the inner wall (21a, 41a, 71a).
4. Drop shaft arrangement (50) according to claim 2, characterized in that the at least one endless stripping element (52) is arranged so that it is arranged to extend in the region of the inner wall (51a) within the drop shaft (51).
5. Drop shaft arrangement (60; 70) according to claim 1, characterized in that two winding devices (63) are provided, wherein the flexible stripping element (62) is connected to the winding devices (63) so that it can be wound up by the winding devices (63) and be unwound therefrom.
6. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the claims 1 to 5, characterized in that the drive means are arranged to set the at least one flexible stripping element (22; 52; 62) in a circulating motion and/or a reciprocating motion in the direction of the longitudinal extension of the stripping element (22; 52; 62).
7. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the claims 1 to 6, characterized in that the at least one flexible stripping element (22; 52; 62) extends adjacent to the inner wall (21a; 41a; 61a) of the drop shaft (21; 41; 61) in a substantially vertical direction and/or extends in the vertical direction according to a shape of the drop shaft (21; 41; 61).
8. Drop shaft arrangement (20; 40) according to one of the claims 1 to 7, characterized in that further clamping means, preferably a spring (24) with pressure roller (25), are provided, which are designed that the at least one flexible stripping element (22) is held under tension.
9. Drop shaft arrangement (20; 40; 60; 70) according to one of the claims 1 to 8, characterized in that further a cleaning device (26; 66) is provided, wherein the at least one stripping element (22; 52; 62) is guided to extend past the cleaning device (26; 66) or through the cleaning device (26; 66).
10. Drop shaft arrangement (20; 40; 60; 70) according to claim 9, characterized in that the cleaning device (26; 66) is designed as a fluid bath, a brush, a stripper edge or a stripping cylinder.
11. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the claims 1 to 10, characterized in that the scraper (27, 47) is designed as a scraper blade, a stripper, a spatula, or a rod.
12. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the preceding claims, characterized in that the at least one flexible stripping element (22; 52; 62) is formed as a rope, in particular a wire rope, a wire, a band or a chain.
13. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the preceding claims, characterized in that the drop shaft (21; 41) is formed to taper in cross-section in the direction of fall of the particles (1) from top to bottom.
14. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the preceding claims, characterized in that the drop shaft (21; 41) is formed in a cylindrical or conical manner.
15. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the preceding claims, characterized in that the drop shaft (41) has a substantially concave shape.
16. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the preceding claims, characterized in that the inner wall (21a; 41a; 71a) is stripped at least once every two minutes.
17. Drop shaft arrangement (10; 20; 40; 50; 60; 70) according to one of the preceding claims, characterized in that a tempering device is further provided for tempering the inner wall (21a; 41a; 71a) to a temperature which lies below a threshold for the curing of the binder, preferably below 70°C.

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