EP3225738B1 - Ground milling machine, in particular road milling machine, for removing soil material and method for operating a ground milling machine - Google Patents

Description

The invention relates to a ground milling machine, in particular a road milling machine, for removing soil material and to a method for operating a ground milling machine.

The invention is generally concerned with the control of dust in the working operation of a ground milling machine, especially in the environment of the machine operator. This is for example in the DE102012022879B4 described in more detail, which is incorporated herein by reference. The resulting during operation of such Bodenfräsmaschinen dust pollution is disadvantageous for the machine operator and for persons in the immediate vicinity of the construction machine for safety and health reasons. There is therefore an attempt to reduce the dust emission of a ground milling machine in working mode as much as possible or at least in particular to relieve the operator of an excessive dust load. A particularly intense dust development occurs especially in ground milling machines of the type road milling machine, in particular road cold milling machine, and so-called surface miners. Such ground milling machines comprise a machine frame with a running gear, a milling drum mounted on a machine frame, a transporting device with at least one conveyor belt, which is arranged on the machine frame and for the removal of removed soil material, the milled material, in a conveying direction away from the Milling roller is formed towards a discharge point. Soil milling machines of the generic type thus have at least one milling drum as a working device, which mills with its axis of rotation horizontally and transversely to the working direction rotating soil material. The milled material is then removed from the Fräswalzenkasten inside which the milling drum is arranged, transported by a transport device, usually comprising at least one conveyor belt away from the milling drum in the conveying direction to a transfer point, in which the milled material, for example, in a means of transport, especially a truck, or is dropped on the ground next to the construction machine. The conveying direction in the present case thus denotes the transport direction of the milled material away from the milling drum. The central point of the dust development is in particular the area of the milling drum or of the milling drum box with the rotating milling drum arranged therein as well as the transport device. Typical ground milling machines are road milling machines, stabilizers, recyclers or surface miners.

In the prior art, suction devices are already known for ground milling machines, which generate a negative pressure in the milling drum box and extract from there the dusts and vapors produced during the milling work. For this purpose, a suction device connected to a channel via a suction opening for extracting dust is provided, wherein the suction opening is arranged between the channel inlet and the channel outlet. The channel designates the conveying path of the material to be milled from the point of delivery thereof to the transport device up to the delivery point, wherein the channel in this region is usually formed at least partly enveloping the transport device. Preferably, the suction opening is mounted in the vicinity of the channel entrance. Such a construction machine is for example in the DE 102 23 819 A1 described, which is hereby incorporated into the construction and operation of a generic construction machine in reference. In order to prevent suction of air through the channel exit to the suction out, there the attachment of rubber mats is described at the channel exit, which at least partially seal the channel exit in the conveying direction to the outside. However, it has been shown that these rubber mats are extremely susceptible to wear, in particular due to the sharp-edged nature of the milled material. An alternative, virtually wear-free option is in the DE102012022879B4 described, after which a blocking flow is generated with a Fluidausströmeinrichtung to allow a defined flow guidance of the dust-laden air.

However, the known possibilities for reducing the dust emission of a ground milling machine are still unsatisfactory. It is therefore an object of the invention to provide a way to further reduce the dust emission in a generic ground milling machine.

The solution of the problem is achieved with a ground milling machine and a method according to the independent claims. Preferred developments are specified in the dependent claims.

An essential basic idea of the invention is to provide an electrostatic precipitator on the ground milling machine, via which dust emerging from the dust-laden air can be separated via the dust arising during the milling operation and / or during the transport of milled material. Under an electrostatic precipitator or electrostatic precipitator in the present case is generally understood a device, which allows separation of airborne particles, especially particulate matter, by the electrostatic principle. By way of example, dust particles with an aerodynamic diameter of not more than 50 μm and in particular of not more than 30 μm are understood to mean, for example, the charging of the dust particles and subsequent deposition in a manner basically known per se in the prior art. The advantage of using an electrostatic precipitator in the present case is that, in particular with respect to the fine dust content significantly improved filter results can be achieved and in this way the dust load of the operator of the ground milling machine and bystanders can be reduced. In addition, it has been shown that the electrostatic precipitator can be integrated particularly favorably into a ground milling machine and can also be operated reliably there. At the same time the deposition results are very good, so that with the arrangement according to the invention a particularly efficient reduction of dust is possible. An electrostatic precipitator itself is for example in the WO2013 / 070078 A1 describe, which is incorporated herein by reference.

It is preferred if the electrostatic precipitator is arranged there or at least in the vicinity where the dust pollution occurs or is relatively high compared to the environment. In principle, it is thus possible, for example, to arrange the electrostatic precipitator close to the milling drum box, for example in the outlet area of the material to be milled from the milling drum box. This arrangement has the advantage that the electrostatic precipitator is integrated directly into the machine body, thereby enabling a particularly compact design of the entire machine. Alternatively, it is preferred if the electrostatic precipitator is arranged on the transport device, in particular on a trailer conveyor belt. The transport device follows in relation to the material flow of the material to be milled to the milling drum or the Fräswalzenkasten, so that the dust load in this area is usually also relatively high. In addition, the transport device and in particular the trailer conveyor belt is particularly suitable for space-technical reasons for the arrangement of the electrostatic precipitator, especially since the electrostatic precipitator at this point (trailer conveyor) from the outside, for example, for maintenance and / or cleaning purposes, is easily accessible. This area is also particularly suitable for mounting a retrofitted electrostatic precipitator.

In concrete terms, the transport device may comprise a transfer conveyor belt and, in the conveying direction behind, a loading conveyor belt. The transfer conveyor belt is often arranged inside the ground milling machine or inside the machine body, whereas it is regularly in the loading conveyor belt is a so-called trailer conveyor belt, which is attached to the machine frame of the ground milling machine. With the transfer conveyor Primarily the conveying of the milled material from the milling drum or from the milling drum box takes place to the downstream in the conveying direction Verladeförderband. With the loading conveyor, however, the actual loading of the material to be milled takes place, for example, on a corresponding transport vehicle. For transport purposes, it is also advantageous if the ground milling machine is as small as possible in total with respect to its longitudinal extent. It is known in the art to form the loading conveyor foldable with a machine part and a folding part, wherein the folding part to the machine part, in particular preferably coming from below, is foldable. In other words, the loading conveyor belt is connected with the rest of the ground milling machine via the machine part, and the folding part forms the drop-off area of the loading conveyor belt that can be folded for transport purposes. It is now preferred if the electrostatic precipitator on the loading conveyor belt and especially if a foldable loading conveyor belt is used, is arranged on the machine part of the loading conveyor belt. This place is on the one hand for reasons of space especially for the arrangement of this additional module. On the other hand, it has been found that the arrangement at this point is particularly suitable for guiding the dust-laden air and a sufficient reduction of dust pollution, especially in the range of a control station of the ground milling machine and in the discharge area of the loading conveyor allows. For visibility and weight distribution reasons, it is also ideal if the loading conveyor is designed such that the folding part is foldable from below to the machine part and the electrostatic precipitator is mounted on top of the machine part accordingly.

To obtain a compact machine, it is also possible that the electrostatic precipitator is disposed within the machine body. The machine body referred to in the present case in particular the outer skin of the machine, which is usually formed by hoods, sheets, etc. In this embodiment, the electrostatic precipitator is thus not attached to the outside of the machine, but positioned in the interior thereof. In this way, the external dimensions of the machine are not additionally increased by the inventively provided electrostatic precipitator. It is preferred that the Bodenfräsmaschine has at least one transfer conveyor on which out of the Fräswalzenkasten milled material is transferred directly and over which the milled material is transported out of the machine inside, wherein for receiving the transfer conveyor belt a storage shaft is present, and wherein the Elektroabscheider at least is partially disposed within this storage shaft. The storage shaft thus denotes an existing inside the machine elongated tunnel-like recess into which, for example, the transfer conveyor belt can be inserted coming from outside. This storage shaft is particularly well suited for accommodating the electrostatic precipitator, since the already existing for conventional machines Space is already large enough for additional inclusion of Elektroabscheiders or at least only slightly increased must.

In order to enable a defined guidance of the dust-laden air produced during the milling process, according to the invention a pump device, in particular a suction device, is provided, with which the dust-laden air can be conveyed. Such pumping devices, for example corresponding blowers, are known in principle in the prior art, such as in the DE 10223819 A1 and DE 102012022879B4 disclosed. According to the invention, it is now provided that the pumping device, in particular in the form of a suction device, is designed such that it supplies dust-laden air to the electrostatic precipitator. This makes it possible, in particular, to achieve targeted dust extraction from dust-laden areas and guidance of the dust-laden air toward the electrostatic precipitator, in order to allow particularly efficient separation of dust particles from the air.

In the specific embodiment of the flow guidance of the dust-laden air can be made use of various alternatives. It is advantageous, for example, if the pump device has a suction device, via which dust-laden air is sucked off the milled material and its immediate surroundings, wherein the suction device is designed in particular such that the suction direction on the input side to the suction device runs at least partially counter to the conveying direction of the milled material. In this development according to the invention, the dust-laden air is thus deflected once compared to the conveying direction of the milled material, in particular by more than 90 °. This has the advantage that larger entrained in the air flow generated by the promotion of the milled material, such as small pieces of milled etc., are separated due to their inertia from the sucked dust-laden air flow, which ultimately, for example, the electrostatic filter is spared.

According to the invention, it is further provided that a flow shaft is present through which the dust-laden air is guided by means of the pumping device. A flow shaft thus designates a channel-like, in particular static, flow-guiding section, in particular with one or more shaft walls, comprising an air inlet, a dedusting section and an air outlet. The electrostatic precipitator is now arranged with at least one charging stage and at least one separation stage within this flow shaft. The charge level of the electrostatic precipitator refers to the area responsible for the electrostatic charge of the dust particles. In contrast, the separation stage designates that part of the electrostatic precipitator from which the electrostatically charged dust particles be attracted and deposited on this. The flow shaft itself can be varied manifold in an advantageous manner.

In principle, it is possible to carry out the flow shaft, for example, as housing around at least part of the transport device. In this way, a particularly compact overall design of the transport device and the electrostatic precipitator can be obtained. The conveying channel of the transport device and the flow shaft of the electrostatic precipitator then form a common space, wherein a mechanical barrier between the subspace of the electrostatic precipitator and the subspace of the conveying channel is additionally preferably provided, for example a grid, in order to prevent damage to parts of the electrostatic precipitator by components of the milled material , However, it is also possible that the flow shaft is at least partially formed spatially separated from a conveying channel surrounding the conveyor belt. In this way, the transport of the milled material and the deposition of dust particles from the dust-laden air thus take place in different compartments. As a result, on the one hand improves the deposition rate of the electrostatic precipitator and on the other hand damage to the electrostatic precipitator can be reliably prevented by the milled material. It is ideal here if the electrostatic precipitator is arranged and formed completely separate from the conveying channel.

The flow shaft of the electrostatic precipitator is preferably designed such that it opens on the output side into the conveyor channel, in particular above the conveyor belt. The dust-laden air is thus sucked first, for example, in the field of Fräswalzenkastens and / or the transfer conveyor belt, branched off and fed to the electrostatic precipitator. After the passage of the electrostatic precipitator, the now cleaned air is returned to the conveyor channel, in particular above the conveyor belt. In this way, no separate air outlet on the ground milling machine for the purified air is required and it can be blown in particular output side of the conveyor channel together with the milled material. For this purpose, it can also be provided that at least one connecting line is present beyond the flow shaft, which adjoins, for example, in the flow direction. By means of the, in particular flexible, connecting line, the dedusted air emerging from the flow shaft can then be conducted, for example, to the conveying channel and / or to the outside environment.

It is ideal if the flow shaft of the electrostatic precipitator is arranged on the conveying channel of the transporting device or is placed thereon. The flow shaft of the electrostatic precipitator then forms a compact unit with the conveying channel of the transport device. This may in particular be the loading conveyor belt or even the inner area of a storage shaft, as described above, in particular for a transfer conveyor belt.

It can also be provided that the electrostatic precipitator is designed such that the air to be cleaned is guided in a substantially straight line through it. However, it may also be advantageous if the air duct in the electrostatic precipitator takes place such that the air is once again diverted several times within the electrostatic precipitator, for example by suitable guide surfaces, etc., whereby in particular not directly impinged conducting surfaces can in particular also be used as separating elements of the electrostatic precipitator ,

For example, the electrostatic precipitator is preferably designed such that the charging stage is an anode, in particular in the form of a corona electrode , and the deposition stage is a cathode. The electrostatic charge of the dust particles is thus preferably such that they are positively charged. This type of charging has proven to be particularly efficient for the present application. The separation stage is accordingly preferably negatively charged. In this way, a particularly efficient agglomeration of dust particles and subsequent deposition takes place on the separation stage. However, it is also possible and expressly encompassed by the invention that the charging stage is the cathode and the deposition stage is the anode. This too can lead to satisfactory deposition results.

In principle, it is possible to adapt the separation stage at will to the respective room conditions. In this case, it is preferable for the separation stage to have the largest possible surface area in order to enable efficient separation of the charged dust particles. Ideally, this is when the separation stage extends longitudinally in the flow direction of the air guided through the electrostatic precipitator in order to obtain a maximum separation distance. The separation stage may be, for example, a plate and / or a grid. Optimal and therefore provided according to the invention it is provided that the separation stage is a, in particular designed as a flow well, housing, at least the inner housing, of the electrostatic precipitator. The separation stage thus fulfills a dual function in this embodiment. In addition to a comparatively large separation surface, it simultaneously forms at least a part of the housing of the electrostatic precipitator. The separation stage may in particular also comprise a plurality of individual separation surfaces and / or be formed in a three-dimensionally deformed manner, in particular curved.

Also with regard to the specific design of the charging stage can be used on a variety of variants. For example, it may be provided that the charging stage is a wire, a wire mesh or even a plate-like structure. It is essential that certain minimum distances are kept to Abscheidestufe to prevent as possible a rollover between charging and separation stage. It is further preferred if the charging step extends in the longitudinal direction of the separation stage, in particular along the flow shaft and / or in the direction of the flow direction of the air. In this way it is possible to maximize the charge path to be passed by the dust-laden air and thereby achieve optimum deposition rates. This therefore means that the charging stage preferably extends in the flow direction of the dust-laden air. In addition, the charging step may additionally or alternatively be designed such that it comprises at least one subregion which runs essentially transversely to the flow direction of the dust-laden air. The charging step then constitutes a type of flow obstruction and / or turbulence stage, which also ensures a high ionization rate of the dust particles in the dust-laden air. Additional turbulence devices, such as, for example, swirl sheaths, can also be provided to improve the charging process.

During operation of the ground milling machine and in particular of the electrostatic precipitator, there is thus a separation of dust particles in the electrostatic precipitator, in particular at the separation stage. In order to keep the efficiency of the electrostatic precipitator as optimal as possible, it is now important that the electrostatic precipitator is cleaned at regular intervals, since dust particles deposited at the separation stage have an insulating effect, for example. For this purpose, it is basically possible to do this for example manually, by interrupting the work process. However, it is preferred if the electrostatic precipitator comprises a cleaning device with which material adhering to the electrostatic precipitator can be removed therefrom. The advantage of the cleaning device is that the cleaning of the electrostatic precipitator can be performed, for example, automatically and / or without time-consuming manual work. For this purpose, the cleaning device can, for example, have a switch-off device, via which voltages applied to the separating stage and the charging stage are switched off during the operation of the conveying device. The electrostatic precipitator is then blown free by means of the pumping device. This effect can be further enhanced if, for example, a pressure pulse can be generated by means of the pumping device. Additionally or alternatively, by means of a Umpoleinrichtung an interval-like and / or short-term Umpolung the Abscheidestufe and the Aufladestufe done to loosen adhering material and solve. The electrostatic precipitator can also be a separate cleaning device with, for example, cleaning nozzles, in particular for Air and / or water, the actuation of which triggers the charging stage and / or separation stage with compressed air and / or water. Water has the advantage here that it binds the separated dust particles. Another possibility consists in a mechanically acting cleaning device, with the deposited on the separation stage dust particles are removed. This may be, for example, a vibrating and / or knocking device, in particular by means of a motor-operated plunger and / or eccentric, so that the separated dust material is cut off from the separating step. A Abschab- and / or Bürsteinrichtung is possible.

In principle, it is possible to blow out the dust removed by means of the cleaning device, for example, from the electrostatic precipitator. However, it is more elegant if the cleaning device has an ejection opening or flap, through which material removed from the separation stage can be removed from the electrostatic precipitator, in particular onto the conveyor belt or into a separate collecting container. By means of the ejection opening and flap thus a connection between the electrostatic precipitator and the conveyor belt / the collecting container is obtained, via which the separated dust material can be returned to the conveyor belt or can be disposed of separately via the collecting container. The ejection opening or flap is preferably designed such that material separated from the separation stage falls through the latter onto the conveyor belt / into the collecting container. This ensures that the cleaned dust material is either loaded together with the other milled material or can be sent to a separate disposal. If recourse is made to a collecting container, this can be provided, for example, to be able to carry a suitable container compartment in order to be able to carry the container or to use an ideally sealed connecting device via which an external collecting container is dust-tight for cleaning purposes at the ejection opening or flap can be connected.

Part of the electrostatic precipitator is preferably also a housing with at least one maintenance flap, through which the access to the interior of the electrostatic precipitator, in particular the charging stage and / or the separation stage, is possible. The maintenance flap is thus closed during regular operation of the electrostatic precipitator. The maintenance flap thus allows access from the outside to the interior of the electrostatic precipitator, for example for cleaning and / or maintenance purposes.

The electrostatic precipitator can be completely and permanently installed in the floor milling machine as a functional unit. Alternatively, it may also be provided, the electrostatic precipitator form as a module, comprising at least one connection means for connecting a, in particular the machine side, electrical power supply. This variant has the advantage that the electrostatic precipitator can be removed and / or replaced comparatively quickly, which may be desirable, for example, if defects occur at the electrostatic precipitator. In the present case, a module is thus referred to as a component unit which can be installed as a contiguous component in the rest of the machine and can be removed again. It is ideal if the electrostatic precipitator for this purpose comprises a releasable holding device for attachment to the ground milling machine, in particular comprising at least one of the features rail guide and / or positive locking and / or clamping fixation. With the help of the releasable holding device on the one hand, the expansion of the electrostatic precipitator succeeds particularly well, since the attachment of the electrostatic precipitator can be solved quickly. On the other hand, the electrostatic precipitator reliably assumes its defined end position during installation due to the holding device, which in turn accelerates and simplifies the installation of the electrostatic precipitator.

It is preferred if a closing state sensor is present, via which the closed state of the maintenance flap can be monitored. Such a closure state sensor may be, for example, a contact switch, in particular a reed contact switch, or the like, which is actuated when the maintenance cover is closed. The closing state sensor is preferably connected to a control unit. The control unit is designed such that it prevents the separating stage and / or charging stage from being supplied with electrical energy when the maintenance cover is open. As a result, the safety for the operating personnel can be increased.

In principle, it is possible to use electrical energy for the supply of the electrostatic precipitator to its own energy source, such as a battery. However, it is preferred if the electrostatic precipitator is connected to the electrical system of the ground milling machine for the supply of electrical energy. This is ideally done with the interposition of a converter.

Also included in the invention are embodiments in which at least two electrostatic precipitators are connected in parallel or at least two flow shafts are provided. In this way, the deposition results can be further improved. Additionally or alternatively, two electrostatic precipitators can also be connected in series.

It can also be provided that additional purification stages are provided in addition to the electrostatic precipitator. Thus, it is possible, for example, to provide a centrifugal separator (cyclone filter), in particular in the flow direction of the dust-laden air in front of the electrostatic precipitator. with the coarser particle before the electrostatic precipitator are removable from the dust-laden air. Also, a grid and / or at least one labyrinth filter stage may be provided. Thus, if an upstream filter stage is used, it is ideally designed to cause only a small pressure drop across that filter stage. Additionally or alternatively, it can also be provided that a Nachfilterstufe is present for the deposition of particulate matter in particular, which is downstream of the electrostatic precipitator in the flow direction, wherein the Nachfilterstufe is in particular a further electrostatic precipitator. With this variant, therefore, particularly good separation results can be achieved. This increased effort is particularly useful when working with problematic materials, such as asbestos, and / or indoors. Additionally or alternatively, it is also possible to provide a Wasserberieselungseinrichtung in addition to the electrostatic precipitator. This is arranged in particular in relation to the flow direction of the air moved through the pumping device in the area behind the electrostatic precipitator, especially in the region of the loading conveyor belt. With the help of the water sprinkling device, it is possible to produce a type of water barrier or curtain or spray wall, which must be passed by the air guided through the electrostatic precipitator before it leaves the conveying channel in particular. Specifically, the sprinkler can be, for example, one or more nozzles and / or a spray bar. With the help of the water sprinkler, an efficient capture of dust particles that are still present in the air after passage of the electrostatic filter succeeds. It is optimal if measures are taken to charge the water discharged from the water sprinkling device in an analogous manner to the separation stage, which can be achieved, for example, by means of a corresponding ground connection. In this way, the cleaning effect achieved with the sprinkler can be further improved. Furthermore, the sprinkler is optimally arranged such that the water discharged from it is collected by the conveyor belt, in particular the Verladefördeband. In operation, the discharged water is then ejected together with the milled material.

Another aspect of the invention lies in a method for operating a ground milling machine, in particular for reducing the dust load during operation of a ground milling machine. The method relates to the operation of a ground milling machine according to the invention. Essential steps of the method according to the invention are A) performing a milling operation, B) passing dust-laden air towards an electrostatic precipitator, C) charging and separating dust particles in the electrostatic precipitator and D) blowing out the cleaned air. It is thus essential for the method according to the invention for operating a ground milling machine that an electrostatic precipitator be used to reduce the dust load, the dust-laden air is supplied for cleaning. Only the cleaned air is blown out after the passage of the electrostatic precipitator, so that the operator of the ground milling machine as well as bystanders are only exposed to a lower dust load. In step B), in particular, the dust-laden air is extracted from the area of the milling drum box, in particular via a suitable suction fan. The dust-laden air is then preferably led out of the interior of the ground milling machine and forwarded to the electrostatic precipitator. In step C), the positive charge of the dust particles is provided in particular. In step D), the purging is particularly preferably carried out by returning the air into the conveying channel of the transport device and not at a separate location on the ground milling machine, which is also possible and included in the invention.

The inventive method can also be further improved if in step B) a suction of the dust-laden air from the Fräswalzenkasten and / or a conveying channel for milled material takes place and / or if in step C) the charging and depositing in a separate from the conveyor channel flow shaft he follows. Essential in these preferred developments is first the targeted extraction of dust-laden air from the Fräswalzenkasten and / or a conveyor channel for milled material. The extracted dust-laden air is then fed to the electrostatic precipitator in a spatially separate area for deposition. In this way, therefore, a separate Entustaubungsstrecke is obtained, which is spatially separated from the transport path of the material to be milled (conveyor channel). On the one hand, this enables a particularly efficient separation of the dust contained in the dust-laden air. On the other hand, it can be ruled out that parts of the electrostatic precipitator are damaged by the milled material.

It is optimal if the charging and depositing of dust particles in the electrostatic precipitator in the flow direction of the air is followed by passing through a water curtain or a water sprinkling device. In this way, two cleaning stages are thus connected in series, whereby a particularly efficient removal of dust particles from the dust-laden air takes place.

It can also be provided that upstream of the charging and depositing of dust particles in the electrostatic precipitator in the flow direction of the air separation takes place, in particular in comparison to particulates of coarse-grained particles with a pre-filter stage, for example to prevent damage to the electrostatic precipitator. With regard to the specific embodiment of the pre-filter stage, reference is made to the preceding statements.

Figur 1:

eine Seitenansicht auf einen Arbeitszug mit einer Bodenfräsmaschine und einem Transportfahrzeug;

Figur 2:

eine Vergrößerung der Bodenfräsmaschine aus Figur 1;

Figur 3:

eine schematische Ausschnittsdarstellung der Transporteinrichtung sowie des Elektroabscheiders aus den Figuren 1 und 2;

Figur 4:

ein Ablaufdiagramm eines erfindungsgemäßen Verfahrens;

Figur 5:

eine Seitenansicht auf eine Bodenfräsmaschine in einer zweiten Ausführungsform;

Figur 6:

eine Seitenansicht auf eine Bodenfräsmaschine in einer dritten Ausführungsform; und

Figur 7:

eine Seitenansicht auf eine Bodenfräsmaschine in einer vierten Ausführungsform.

The invention will be described in more detail with reference to the embodiments given in the figures. They show schematically:

FIG. 1:

a side view of a work train with a ground milling machine and a transport vehicle;

FIG. 2:

an enlargement of the ground milling machine FIG. 1 ;

FIG. 3:

a schematic sectional view of the transport device and the Elektroabscheiders from the FIGS. 1 and 2 ;

FIG. 4:

a flow diagram of a method according to the invention;

FIG. 5:

a side view of a ground milling machine in a second embodiment;

FIG. 6:

a side view of a ground milling machine in a third embodiment; and

FIG. 7:

a side view of a ground milling machine in a fourth embodiment.

Identical or functionally identical components are identified in the figures with the same reference numerals, wherein not every repeating component in the figures is necessarily designated in each figure.

The work train 1 in FIG. 1 In milling operation, the ground milling machine 2 drives its own drive behind the transport vehicle 3 in the direction of A. Essential elements of the transport vehicle 3 are a control station 4 and a loading area 5 for receiving milled material , The ground milling machine 2 comprises, in addition to a control station 6, a machine frame 46 (FIG. Fig. 2 ), Chassis (crawler tracks or wheels), a drive motor, a milling device 7 and a transport device 8, with which the milled material obtained from the milling device 7 to the discharge point 9 of the transport device 8 is transportable. For this purpose, the transport device 8 comprises a transfer conveyor belt 10 arranged inside the ground milling machine 2 and a loading conveyor belt 11. Furthermore, the ground milling machine 2 has an electrostatic precipitator 12 which is arranged on the loading conveyor belt 11 of the transport device 8. By means of the electrostatic precipitator 12, it is possible to arise during the milling process and the transport of the material to be milled To separate dust. The electrostatic precipitator 12 is connected to a pumping device 13, specifically a blower.

FIG. 2 clarifies further details of the structure of the ground milling 2 from FIG. 1 , Specifically, the milling device 7 comprises a milling roller box 14 and a milling roller 15. Within the milling roller box 14, the milling roller 15 can be moved in a known manner about a horizontal axis of rotation perpendicular to the working direction A. The milled from the milling drum 15 soil material is loaded from the Fräswalzenkasten 14 out on the transfer conveyor belt 10 and transported within a conveyor channel 16 within the ground milling machine 2 to the loading conveyor belt 11. The loading conveyor belt 11 is also surrounded by a housing 17, so that the loading conveyor belt 11 extends within a conveying channel 18. The loading conveyor belt 11 or the conveying channel 18 opens into the discharge point 9, from which the milled material, for example on a transport vehicle, is dropped.

An essential part of the ground milling machine 2 is a device for dust extraction and separation, as described in more detail below. In addition to the above-described elements Elektroabscheider 12 and pumping device 13 in the form of a suction fan, the device for dust further comprises a suction channel 19, a connecting line 20, a charging stage 21, a separation stage 22, a cleaning device 23, a supply source 24 for electrical energy and an outlet 25 of the electrostatic precipitator 12. Via the intake channel, dust-laden air is sucked in from the area of the milling drum box 14 and, in particular, also from the region of the conveyor channel 16. The suction fan 13 generates a negative pressure in this area, so that the dust-laden air is drawn in. The suction device 13 is connected via the connecting line 20 with the electrostatic filter 12. Thus, when the dust-laden air reaches the electrostatic precipitator 12 via the connecting line 20, the charged particles are first charged by the charging stage 21 and then the charged dust particles are deposited at the separating stage 22. The charging stage 21 and the separating stage 22 are connected via suitable connecting lines with the electrical energy source 24, which in the present embodiment is a high voltage source (HVPS) connected via a converter to the vehicle electrical system of the ground milling machine 2. The now cleaned air is blown from the electrostatic precipitator 12 via the outlet 25 into the delivery channel 18 and thus also leaves the transport device 8 via the discharge point 9.

The electrostatic filter 12 is arranged on the loading conveyor belt 11. Specifically, it is at the loading conveyor belt 11 to a foldable conveyor belt with a machine part 26 and a folding part 27, which are pivotally connected to each other via a pivot joint 28. In other words, the electrostatic precipitator sits on the "non-foldable" portion of the loading conveyor belt 11.

In FIG. 2 are the flow of air with the dashed arrows B and the conveying direction of the milled material indicated by the arrows C. FIG. 2 makes it clear that the dust-laden air is first separated from the milled material through the intake channel 19 and the dedusting thus takes place at a spatially separate location for conveying the milled material. As a result, the electrostatic precipitator 12 can be protected from damage by the milled material, for example. In addition, it is also possible, for example, to configure the electrostatic precipitator 12 in such a way that the incoming air flow within the electrostatic precipitator is slowed down in order to improve the precipitation result, for example by enlarging the flow cross section.

With the aid of the cleaning device 23, it is possible to remove dust deposited within the electrostatic precipitator 12 from the separation stage 22. For this purpose, the cleaning device 23 can be actuated, for example, from outside the electrostatic precipitator 12, automatically triggered after certain operating intervals and / or automatically triggered in certain operating situations, for example when the loading conveyor 11 is put into operation. FIG. 2 not shown) may be provided, via which the operation of the cleaning device 23, in particular automatically, is controllable. In order to facilitate a facilitated removal of the cleaned-off dust material, a connection opening between the bottom of the electrostatic precipitator 12 and the delivery channel 18 can also be present, through which cleaned-up dust from the electrostatic precipitator 12 can fall onto the conveyor belt of the loading conveyor belt 11.

FIG. 2 further clarifies that in the present embodiment, in addition to the electrostatic precipitator 12, a further device for dedusting is available. Specifically, this is a sprinkler 29 (can optionally also in the other embodiments, in particular according to the FIGS. 5 to 7 , be provided in addition), which extends over the width of the conveyor belt or the loading conveyor belt 11 just before the discharge point 9. The sprinkler 29 may, for example, be a spray bar with a plurality of outlet openings or nozzles, with which a kind of water curtain is produced. The supply of the sprinkler 29 takes place via a supply line 30 a water tank 31 at the ground milling machine 2. The water discharged from the sprinkler 29 falls in the present embodiment on the transported over the loading conveyor milled material. Optionally via the sprinkler 29 intercepted dust particles are thus unloaded accordingly along with the milled material on the discharge point 9. The cleaning of the dust-laden air of the ground milling machine 2 is thus carried out in two stages in the present embodiment, wherein the electrostatic precipitator 12 of the sprinkler 29 is upstream in the flow direction of the dust-laden air.

FIG. 3 Finally, the structure and the arrangement of the electrostatic precipitator 12 are further illustrated in a schematic representation. The electrostatic precipitator 12 itself is shown in solid lines. Essential elements of the electrostatic precipitator 12 are a box-like housing 32 and disposed within the housing 32 charging plates 33, which form the charging stage 21. The housing 32 is formed with a longitudinal extent parallel to the longitudinal extent of the loading conveyor belt 11 indicated by dashed lines and thus forms a parallel to the conveyor channel 18 extending flow shaft 47 for the dust-laden air to be cleaned. The charging plates 33 extend in the longitudinal extent of the housing 32 and the flow shaft 47. The charging plates are connected as the anode 34 and the housing 32 accordingly as the cathode 35. The charging plates thus form the charging stage 21 and the housing 32 of the electrostatic precipitator the separation stage 22 of the electrostatic precipitator 12th

The supply of sucked on the pumping device 13 dust-laden air (dashed arrows B) takes place from the top of the housing 32 via a corresponding feed opening 36. Alternatively, for example, the supply from the side via an optional opening 36 'is possible. Within the electrostatic precipitator 12, the electrostatic charge of the dust particles thus takes place via the charging plates 33, which extend sufficiently spaced from the housing 32 also in the longitudinal direction of the housing 32. Accordingly, the electrostatically charged dust particles are attracted to the housing 32 and thus separate therefrom within the electrostatic precipitator 12. The purified air is blown out of the electrostatic precipitator 12 via the outlet opening 37 into the delivery channel 18 above the loading conveyor belt 11. Alternatively, it is also possible, for example, to blow out the purified air via other passages, for example via an outlet opening 37 'to the outside environment.

In the housing 32 of the electrostatic precipitator 12 maintenance flaps 38 are also attached to the long sides. The maintenance flaps 38 can be opened so that access from the outside in the interior of the electrostatic precipitator 12 is possible. This may be desired, for example, for maintenance and / or cleaning purposes. In order to prevent external access to the interior of the electrostatic precipitator 12 during operation of the electrostatic precipitator 12, a closing state sensor 39 is provided, which is connected via a connecting line 40 to a corresponding control unit. The control unit (not shown in the figures) is designed such that it forcibly interrupts the operation of the electrostatic precipitator 12 or its supply of electrical energy when the closure state sensor 39 signals that the maintenance flaps 38 are open. In other words, operation of the electrostatic precipitator 12 in the present embodiment is possible only when the maintenance flaps 38 are closed.

Fig. 3 illustrates the schematic structure of a single electrostatic precipitator 12. Included in the invention are also expressly variants in which two or more of these electrostatic precipitators 12 are arranged in particular connected in parallel, so that the extracted dust-laden air to the individual electrostatic precipitators 12 is supplied split. This also includes embodiments in which the plurality of electrostatic precipitators 12 are surrounded by a common housing.

In Fig. 3 the electrostatic precipitator 12 is further designed as a structural unit or as a module 55. The module 55 comprises the housing 32, the charging stage 21, the separation stage 22 and unspecified connections for supply lines to the anode 34 and to the cathode 35 for connection to the machine 1. The electrostatic precipitator 12 is on both sides or on two mutually releasable holding means 56 opposite sides on the conveying channel 18 (also the arrangement within the machine itself, as shown below, in particular also on or in the conveying channel 16, is possible) surrounding the housing. Concretely, the holding devices 56 may be, for example, screw connections, rail bearings, form-locking bearings, detent bearings, etc., or combinations thereof. The electrostatic precipitator 12 can therefore also be easily dismantled or, conversely, retrofitted to existing machines. But it is also possible to obstruct the electrostatic precipitator 12 for permanent retention in the machine.

FIG. 4 illustrates the flow of a method according to the invention for operating a ground milling machine, in particular for reducing the dust load. This method particularly relates to the operation of a ground milling machine, as in the FIGS. 1 to 3 shown. Essential steps of the method according to the invention are first performing 42 of a milling process. During this milling process, considerable amounts of dust are produced. According to the invention, it is therefore provided that conduction 43 of dust-laden air to an electrostatic precipitator 12 takes place. This can be done in particular via a suitable pumping device 13, in particular a suction fan, as described above, and corresponding connecting lines. Subsequently, charging and depositing of dust particles in the electrostatic precipitator 12 takes place within the electrostatic precipitator in step 44. Charging takes place by passing through a charging stage and depositing by depositing the electrostatically charged dust particles on the separating stage. Finally, the purging out 45 of the purified air from the electrostatic precipitator 12, for example in the outside environment or in particular in the delivery channel 18 of the conveyor belt, in particular the loading conveyor belt 11th

The method according to the invention provides particularly good cleaning results, in particular, when the charging and depositing of the dust particles in the air takes place in a space compartment separate from the conveying channel of the material to be milled. The method according to the invention thus also includes a step in which the dust-laden air is separated, for example sucked, away from the milled material.

Furthermore, the cleaning result of the method according to the invention can be increased if the separation of dust particles by means of the electrostatic precipitator according to the steps 42 to 45 is followed by an additional cleaning stage 46, in which the air, for example, a water curtain, in particular a corresponding sprinkler, as described above, happens. In particular, particularly small, electrostatically charged dust particles, which have passed through the electrostatic precipitator 12 in an undesired manner, are still largely trapped in this way.

Additionally or alternatively, it is also possible that prior to the separation steps 42 to 45, a pre-cleaning of the dust-laden air according to step 49, for example by a cyclone filter and / or a filter grid and / or a labyrinth filter stage. As a result, coarse-grained particles can be sucked in with the dust-laden air and reach the electrostatic precipitator 12.

The Figures 5 . 6 and 7 illustrate advantageous modifications of the embodiment according to FIG. 2 In the following, essentially the existing differences will be emphasized and otherwise reference is made to the relevant explanations concerning the first exemplary embodiment.

Essential in the embodiment according to FIG. 5 is first that the electrostatic precipitator 12 is here inserted into the interior of the machine 2. The electrostatic precipitator 12 is thus surrounded by the body 50 or the outer skin of the machine 2 (the loading conveyor 11 is not part of the body 50). Thus, a particularly compact machine can thus be obtained. In addition, the electrostatic precipitator in relation to the conveying path of the milled material has moved considerably closer to the milling drum box 14. He sits concretely above the transfer conveyor belt 10 within the machine-side conveyor channel 16 and thus substantially in the cavity within the body 50, in which the transfer conveyor belt 10 is arranged. In the flow direction of the dust-laden air (dashed arrows B) immediately before the electrostatic precipitator 12, a protective grid 51 is further provided, which prevents coarser Fräsgutpartikel be sucked into the electrostatic precipitator 12. The protective grid 51 extends in a substantially horizontal plane. The protective grid 51 thus represents a physical barrier for coarser particles of milled material for the protection of the electrostatic precipitator 12. Instead of the protective grid 51, it is also possible, for example, to provide a labyrinth filter stage. The electrostatic precipitator further comprises an apron 52 on its underside facing the transfer conveyor belt 10. This is reinforced and protects the overlying Elektroabscheider 12 from damage by the milled material. The fender 52 extends over the entire length of the electrostatic precipitator 12 in the conveying direction of the milled material. Finally, it is also essential that, in the present exemplary embodiment, the pump device 13 is positioned behind the electrostatic precipitator 12 in the conveying direction of the dust-laden air. As a result, the dust load of the pumping device 13 itself is significantly reduced compared to the previous embodiment, so that it is less burdened by dust.

Another alternative embodiment is in FIG. 6 illustrated. Again, the electrostatic precipitator 12 is arranged on the machine side in the surrounded by the body 50 interior of the machine 2 integrated. However, the electrostatic precipitator 12 is not seated within the delivery channel 16 but is placed above the delivery channel 16 without direct contact therewith in the interior of the machine. A deflecting device 53, via which the dust-laden air is fed to the electrostatic precipitator 12, is also connected upstream of the electrostatic precipitator 12. It is essential that seen in the conveying direction of the milled material, a deflection of the dust-laden air using the deflection takes place. In fact, the dust-laden air is sucked in by the deflecting device 53 counter to the conveying direction of the milled material. This can be counteracted the suction of larger Fräsgutpartikel in the deflecting 53 into. In this case, the deflection angle (angle between the conveying direction of the material to be milled and the direction of entry the dust-laden air in the deflection 53 ideally greater than 90 ° and especially greater 120 °.

Optionally, a collection container 54 is further provided below the electrostatic precipitator 12. This can be used to clean the electrostatic precipitator 12. Tapped, deposited on the electrostatic precipitator 12 dusts can fall during cleaning by an unspecified connection opening between the electrostatic precipitator 12 and the reservoir 54 in this. By removing the collection container 54 from inside the machine, the separated dusts can then be disposed of separately. For this purpose, the collecting container can either be used permanently in the machine 1 or can be used especially for cleaning work on the electrostatic precipitator 12.

In the embodiment according to Fig. 7 Finally, no pumping device 13 is provided in comparison to the preceding embodiments. Instead, the electrostatic precipitator 12 is formed with its bottom open to the conveyor channel 16 out, wherein on the underside of the electrostatic precipitator over its entire length extending protective grid 51 is present. The dust-laden air is thus not selectively supplied to the electrostatic precipitator 12 here. However, due to the conveying movement of the milled material within the conveying channel 16, a directed air flow, through which ultimately at least part of the dust-laden air coming from below, is supplied to the electrostatic precipitator. Using the in Fig. 7 already shown an effective reduction of the dust content in the air can be achieved. To further improve the rate of deposition, is in FIG. 7 the electrostatic precipitator 12 in the interior of the machine, a further Elektroabscheider 12 downstream, which is arranged on the loading conveyor belt 11. This is also open in the manner described above on its underside for milled material located on the loading conveyor belt 12, so that even there dust-laden air is passed to the electrostatic precipitator 12. By the series connection of the two electrostatic precipitators 12, a sufficient overall deposition rate for many applications can be achieved without the need for an additional pumping device. The cleaning result of the dust-laden air can also by the zu Fig. 2 sprinkler described with water curtain can be further improved.

Both electrostatic precipitators 12 are in FIG. 7 supplied by a common supply device 24 with electrical energy. It can be provided for both electrostatic precipitators 12 but also a separate, individual supply device 24. It is equally possible for the electrodes of the electrostatic precipitator to be connected to the supply device via a common supply line 24 to connect (in Fig. 7 for the electrodes 22 the case) or to provide individual supply lines (in Fig. 7 for the electrodes 21 the case). The latter has the advantage that an individual control of the two electrostatic precipitators 12 is easier, whereas for the first variant a lower installation effort is necessary. Usually, the electrodes of the two electrostatic precipitator 12 in Fig. 7 all individually or in pairs connected to the supply device 24 together.

Claims (16)

1. A ground milling machine (2), in particular road milling machine, for removing ground material, comprising

   - a machine frame (46) having a chassis,

   - a milling drum (15) mounted on the machine frame (46), and

   - a transport device (8) having at least one conveyor belt, which is configured for transporting removed ground material in a conveying direction away from the milling drum (15) to a discharge point (9),

   characterized in that
   it comprises an electrostatic precipitator (12), by means of which dust generated during the milling operation and/or during the transport of milled material can be precipitated,
   it comprises a pump device (13), by means of which dust-laden air can be conveyed, the pump device (13) being configured such that it feeds dust-laden air to the electrostatic precipitator (12),
   a flow duct (47) is provided, through which the dust-laden air is routed using the pump device (13),
   the electrostatic precipitator (12) is arranged with at least one charging stage (21) and at least one precipitation stage (22) within the flow duct (47),
   the precipitation stage (22) is a housing (32) of the electrostatic precipitator (12).
2. The ground milling machine (2) according to claim 1,
   characterized in that
   the electrostatic precipitator (12) is arranged at the transport device (8), in particular at a suspension conveyor belt (11).
3. The ground milling machine (2) according to any one of the preceding claims,
   characterized in that
   the transport device (8) comprises a transfer conveyor belt (10) and, downstream thereof in the conveying direction, a loading conveyor belt (11), and in that the loading conveyor belt (11) comprises a machine part (26) and a foldable part (27), the foldable part (27) being foldable to the machine part (26), and the electrostatic precipitator (12) being arranged at the machine part (26).
4. The ground milling machine (2) according to any one of the preceding claims,
   characterized in that
   it comprises a machine body, the electrostatic precipitator (12) being arranged inside the machine body.
5. The ground milling machine (2) according to any one of the preceding claims,
   characterized in that
   it comprises at least one transfer conveyor belt, onto which milled material conveyed out of the milling drum box is directly transferred and via which the milled material is transported out of the interior the machine, a duct being provided for receiving the transfer conveyor belt, and the electrostatic precipitator being at least partially arranged inside this duct.
6. The ground milling machine (2) according to any one of the preceding claims,
   characterized in that
   the pump device (13) is a suction device.
7. The ground milling machine (2) according to any one of the preceding claims,
   characterized in that
   the pump device comprises a suction device, by means of which the dust-laden air is suctioned from the milled material and the direct vicinity thereof, the suction device being in particular configured such that the suction direction at least partially runs against the conveying direction of the milled material on the side of the inlet toward the suction device.
8. The ground milling machine (2) according to any one of the preceding claims, characterized in that
   the flow duct (47) in particular comprises at least one of the following features:

   - the flow duct (47) is at least partially spatially separated from a conveyance channel (16, 18) at least partially surrounding the conveyor belt (10, 11), and/or

   - the flow duct is at least partially integrated in a conveyance channel (16, 18) surrounding the conveyor belt, and/or

   - the outlet side of the flow duct (47) ends into the conveyance channel (18) above the conveyor belt (11), and/or

   - the flow duct is followed by a connection line, through which the air exiting the flow duct is routed to the conveyance channel (18) and/or to the external surroundings, and/or

   - the flow duct (47) is arranged on the conveyance channel (18) or inside a machine body.
9. The ground milling machine (2) according to any one of the preceding claims,
   characterized in that
   the charging stage (21) is an anode (34) and the precipitation stage (22) is a cathode (35).
10. The ground milling machine (2) according to any one of the preceding claims, characterized in that
    the precipitation stage (22) comprises at least one of the following features:

    - it is a housing (32) of the electrostatic precipitator (12), which is particularly formed as a flow duct (47);

    - it comprises precipitation elements, which extend longitudinally in the main flow direction;

    - it comprises a precipitation element running at least partially at an angle to the main flow direction;

    - it comprises a precipitation element in the form of a plate or grate;

    and/or the charging stage (21) comprises at least one of the following features:

    - it is a wire, a meshed wire or a plate-like structure;

    - it extends in the longitudinal direction of the precipitation stage (22), in particular along the flow duct (47);

    - it extends in the flow direction of the dust-laden air;

    - it comprises at least one sub-region extending essentially transversely to the flow direction of the dust-laden air.
11. The ground milling machine (2) according to any one of the preceding claims, characterized in that
    a cleaning device (23), in particular a switch-off, pole reversal, nozzle, vibration and/or shaking device is provided, by means of which material adhering to the electrostatic precipitator (12) can be removed therefrom, the cleaning device (23) particularly comprising a discharge opening or discharge flap, through which material cleaned off by the precipitator stage can be removed from the electrostatic precipitator (12), in particular onto the conveyor belt (11), the discharge opening or flap very particularly being configured such that it creates an, in particular vertical and/or direct, passage connection between the electrostatic precipitator and a free space located directly above the conveyor belt (11).
12. The ground milling machine (2) according to any one of the preceding claims, characterized in that
    at least one maintenance flap (38) is provided in a housing (32) of the electrostatic precipitator (12), through which access to an internal space of the electrostatic precipitator (12) is possible.
13. The ground milling machine (2) according to any one of the preceding claims,
    characterized in that
    the electrostatic precipitator (12) comprises at least one of the following features:

    - it is formed as a module, including at least one connection device for connecting an, in particular machine-sided, electric energy supply device;

    - it comprises a detachable holding device for fastening to the ground milling machine, in particular comprising at least one of the features rail guidance and/or form-fit and/or clamping fixation device.
14. The ground milling machine (2) according to any one of the preceding claims,
    characterized in that
    it comprises at least one of the following features:

    - the electrostatic precipitator (12) comprises a closing state sensor (39), via which the closing state of a maintenance flap (38) can be monitored;

    - the electrostatic precipitator (12) is connected to the power grid of the ground milling machine (2) for being supplied with electric energy, in particular using an interconnected converter;

    - a water sprinkling device (29) is provided, in particular with respect to the flow direction of the air moved by the pump device (13) in the area behind the electrostatic precipitator (12), very particularly in the area of the loading conveyor belt (11);

    - a pre-filtering stage for precipitation of particularly coarse particles is provided, which is connected upstream the electrostatic precipitator in the flow direction, wherein the pre-filtering stage particularly is a cyclone separator and/or a grate and/or a labyrinth filter stage;

    - a post-filtering stage for precipitation of in particular particulate matter is provided, which is connected downstream the electrostatic precipitator in the flow direction, the post-filter stage in particular being another electric filter.
15. A method for operating a ground milling machine (2), in particular according to any one of claims 1 to 14, comprising the steps:

    a) performing (42) a milling process;

    b) routing (43) of dust-laden air to an electrostatic precipitator (12);

    c) charging and precipitating (44) of dust particles in the electrostatic precipitator (12);

    d) blowing out (45) the cleaned air.
16. The method according to claim 15,
    characterized in that
    it comprises at least one of the following method steps:

    - in step b), sucking the dust-laden air out of the milling drum box (14) and/or a conveyance channel (16, 18) for milled material is effected, and/or

    - in step c), the charging and precipitation is performed in a flow duct (47) of the electrostatic precipitator (12) running separately from the conveyance channel (16, 18), and/or

    - passage (46) through a water muffler is effected downstream the charging and precipitation of dust particles in the electrostatic precipitator (12) in the air flow direction, and/or

    - a precipitation of coarse particles with a pre-filter stage is effected upstream the charging and precipitation of dust particles in the electrostatic precipitator (12) in the air flow direction.

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