Patent Grant
7175364
The invention relates to an automotive milling machine for machining ground surfaces, particularly roadways, as well as to a method for the disposal of dusts and fumes at a milling machine, which are produced during the milling.
Such milling machines are also called road milling machines.
A front loader milling machine, for example, is known from DE-A-39 03 482 or DE-A 38 31 161. The known milling machines comprise an automotive running gear with a pair of front wheels and a pair of rear wheels. The running gear supports a machine frame in which a milling drum is supported transverse to the traveling direction. To achieve a transportation of the milled-off material that is as complete as possible, the milling drum is typically surrounded by a housing in which the wall pointing towards the traveling direction is configured as a covering shield with a passage opening for the milled-off material. That wall that is the rear one in traveling direction is configured as a stripper and pressed against the milled surface to seal the drum box to the rear in order to supply the milled-off material completely to transportation. The milling drum throws the material worked off by the milling drum onto a first band conveyor which transfers the worked-off material onto a stacker belt at the front end of the milling machine, which is pivotable with respect to its inclination and laterally for the transport onto a floor of a truck.
Another embodiment of these road milling machines, the so-called rear loader milling machine, is known from DE-A 34 05 473, for example. Here, the passage opening for the milled-off material is located in the wall of the drum housing pointing toward the direction opposite to the traveling direction and also being configured as a stripper. The material milled off by the milling roll is directly transferred onto the band conveyor serving as stacker belt and being arranged at the rear end of the milling machine to transport it onto a truck. Like the stacker belt of the front loader milling machine, the stacker belt of the rear loader milling machine may also be pivotable in its inclination and laterally.
The milling drum of such road milling machines is fitted with chisel tools forming a conveying helix transporting the milled-off material to the passage opening of the covering shield.
By milling off the ground surface and by transporting the milled-off material, dusts and fumes are produced which may impair the operativeness of the conveying devices, on the one hand, and worsen the working conditions for the machine operator on the driver stand and for the remaining operating personnel about the milling machine, on the other hand, and possibly even be an obstacle to the view for the traffic that is possibly passing.
From EP 0 971 075, it is already known to provide the band conveyors of a milling machine with a hood, to suck off the produced dust at the milling drum and under the hood of the band conveyors opposite to the transport direction and to dispose of it via a blower and a filtering means at the rear end of the milling machine. It is disadvantageous that the sucking is effected at the band conveyors opposite to the transport direction. Due to the fact that the dusty air is sucked off rearward and opposite to the actual transport direction of the material, considerable additional efforts for the conversion of the machine and a distinctly higher air output of the blower are required. The use of a radial fan at the rear end of the milling machine has the disadvantage that it is not possible to achieve a sufficiently high airflow at the band conveyors that are at the front in the direction of travel. Finally, the particles discarded at the blower and the cyclone filter are thrown onto the ground surface again whereby the ground surface just milled off is soiled again. The cyclone filter provided at the rear end of the machine is only able to segregate the coarser particles but not the respirable fine dusts so that the arrangement of the air outlet at the rear end of the milling machine is arranged too close to the driver stand. The same applies to a mesh-shaped filter that is not able to segregate respirable dusts either. Another disadvantage of prior art consists in that dusts and fumes are blown off at the rear end of the milling machine near the driver stand and that, moreover, dusts are inevitably produced anew when the milled-off material is thrown off at the front band conveyor.
Therefore, it is the object of the invention to provide a milling machine of the afore-mentioned kind as well as a method for the disposal of dusts and fumes where dusts and fumes produced upon milling and conveying can be sucked off with lower requirements as to the machines and with higher efficiency and disposed of together with the worked-off material.
The invention advantageously provides that the suction device is connected to a first section of the duct allocated to the conveying device downstream from the first transfer location and sucks off the air that has been polluted during milling essentially in the direction in which the material is conveyed in the first duct section, the polluted air being sucked off at the milling drum as well.
The invention permits a simple construction where the structure of a milling machine does not have to be changed fundamentally so that a retrofitting of existing milling machines is possible as well.
Sucking off the polluted air in the first duct section permits a sucking near the greatest source of pollution where dusts and fumes are produced. At the milling drum, dusts are produced by breaking up the ground surface and fumes are produced because of the high temperatures during milling, e.g., during milling off asphalt materials. As things develop, dusts may also be produced in the region of the conveying device by the transport of the milled-off material. The arrangement of the suction device in the first duct section of the conveying device permits the application of a strong airflow in the region of the milling roll and the first duct section whereby the discharge of dusts or fumes at the milling roll or at the first duct section is avoided. Therefore, dusts and fumes can be sucked off reliably in the working range of the milling roll and at the location of transfer from the milling roll onto the conveying device. An essential advantage is the improvement of the working conditions on the driver stand and in the environment of the milling machine and the low fault liability of the conveying device. Moreover, the milled ground surface is left clean. An essential advantage of the disposal of the dusts and fumes via the discharge of the conveying means consists in that the development of dust is nearly unavoidable at this site since the milled-off material is thrown off onto the floor of a transport vehicle from a height of several meters. The invention advantageously provides that the dusts and fumes are disposed of exactly where the development of dust is unavoidable anyway. For reasons of working security, standing there is strictly forbidden anyway. The working area on the driver stand and next to the machine, however, is freed from dusts and fumes and particularly from their respirable fractions.
Preferably, the second duct section is separated from the first duct section by separating means for blocking up an airflow without hindering a conveyance of the material.
Preferably, it is provided that the suction device comprises a suction duct connected to the first duct section and an axial fan integrated into the suction duct. The polluted air is disposed of by the first duct section via the suction duct, the axial fan integrated in the suction duct providing for a high negative pressure and a high airflow speed at the suction locations. Another advantage of the axial fan consists in that it can be integrated into the suction duct and is thus arranged in a room-saving manner and simultaneously, it can be arranged close to the suction locations. Another advantage of the axial fan is its indifference to dirt and its self-cleaning effect. The high sucking power does not only permit to suck off respirable dusts and fumes but, moreover, of coarser dust particles as well.
The suction device disposes of the polluted air at that site where dust develops anyway as a consequence of the discharge of the milled-off material from the conveying device.
According to an embodiment of the invention, it is provided that the downstream end of the suction duct opens into an upper section of the second duct section formed by the conveying device. By returning the sucked-off polluted air into the second duct section of the conveying device, it is possible to dispose of the polluted air together with the milled-off material far from the driver stand of the milling machine. By the polluted air entering into the second duct section, the second duct section is also sucked off in the direction in which the material is conveyed because of the injection effect.
The downstream end of the suction duct opens into a second duct section separated from the first duct section by separating means for blocking up an airflow without hindering the transport of the milled-off material. Consequently, a divided duct is formed which extends over the entire length of the conveying device, the separations being effected by the separating means which, on the one hand, do not hinder the transport of the milled-off material and, on the other hand, prevent an airflow opposite to the direction in which the material is conveyed. Thus, the duct sections are sealed off with respect to each other in a substantially air-tight manner.
Preferably, it is provided that the conveying device comprises at least one band conveyor with a conveyor belt and that sealing means for the duct consist of hoods sealing against the conveyor belt or against the housing of the band conveyor. Thus, the hoods form a closed duct together with the conveyor belt or together with the housing of the band conveyor so that the milled-off material travels through the conveying device in a completely peripherally enclosed manner. Thus, no dusts or fumes may emerge to the outside.
A second conveying device may take over the milled-off material at the end of the first conveying device at a second transfer location.
The transfer location between the first and the second conveying device is sealed with flexible sealing means mounted to at least one of the conveying devices. Smaller gaps do not matter since both the first duct section and the lower portion of the second duct section are under a negative pressure so that no polluted air can escape at possible leakages but air is sucked at most.
Preferably, the suction duct enters into the second duct section at an acute angle and shortly in front of the discharge end. The entrance angle reinforces the injection effect so that the lower portion of the second duct section is reliably sucked as well, without any additional suction device.
In a preferred embodiment of the invention, it is provided that an agglomeration means is arranged behind the junction of the suction duct and the second duct section. By means of the agglomeration means, the dusts and fumes can be agglomerated and condensed, respectively, so that they can be disposed of together with the milled-off material.
The agglomeration means may consist of, e.g., a water spraying means arranged at the outlet of the conveying means. By means of the water spraying means, the dusts can be bound and agglomerated and the fumes can be condensed as well.
Alternatively, with respect to the dusts, it is also possible to precipitate them electrostatically.
Between the first and the second duct section of the conveying device, at least one flexible flap is arranged as a separating means downstream and not far from the air intake fitting of the suction device, blocking up the first duct section of the conveying device against air entering opposite to the direction in which the material is conveyed. The milled-off material can pivot the flap in the direction in which the material is conveyed whereas the entry of air opposite to the direction in which the material is conveyed is prevented. The negative pressure in front of the flap reinforces the sealing by sucking the flap onto the milled-off material on the conveyor belt.
If the conveying device is formed of several conveying devices, the separating means is preferably provided at the first conveying device.
The flap may be repeatedly divided by vertically extending slots so that the flap are able to adapt to the contour of the material conveyed on the band conveyor. Preferably, several flaps, divided and/or undivided, are provided behind each other between the first and the second duct section.
At the sides of the at least one conveyor belt, the conveying device comprises hood supports sealed with respect to the conveyor belt by an elastic lip. Thus, the conveyor belt, together with the elastic lip, the hood support and the hoods, forms a completely closed duct cross section tightly enclosing the conveyed milled-off material. Alternatively, the duct cross section may also be formed by several hood portions.
According to the method for the disposal of the air polluted with dusts and fumes during milling at a milling machine for machining ground surfaces, where the material milled off by a milling drum is disposed of via at least one conveying device.
According to a preferred embodiment, the following steps are provided:
Hereinafter, embodiments of the invention are explained in detail with reference to the drawings.
A milling machine 1 for machining surfaces in the configuration of a front loader milling machine is shown in
The milling machine 1 serves to mill off ground surfaces, particularly roadways of asphalt, concrete or the like. The milling machine 1 comprises a running gear with, e.g., four drive units 4 formed by chain running wheels, which supports the engine frame 2. In the engine frame 2, a milling drum 8 is supported which extends transversely to the traveling direction. The adjustment of the milling depth is effected by means of the height adjustment of the drive units 4. The milling machine 1 illustrated in
To achieve a transport of the milled-off material as complete as possible, the milling drum 8 is typically surrounded by a drum box 58 where the wall pointing towards the traveling direction is configured as a shield 52 with a passage opening 56 for the milled-off material.
The milling drum 8 is provided with helically arranged chisel tools arranged such that the milled-off material is transported to the passage opening 56 in the shield 52. At the end of the drum box 58 that is located to the rear in traveling direction, a wall 60 of the drum box 58 forming a tight closure with the milled ground surface is provided, which strips off the milled ground surface so that no fragments of the milled-off material remain on the milled ground surface. With its lower edge, the wall 60 is pressed hydraulically against the ground surface to achieve a sealing as good as possible.
At the engine frame 2, a band shoe 50 as a band protecting and supporting means is height-adjustably mounted in a guide. The band shoe 50 receives the rear end of the first conveying device 14. The passage opening 56 of the drum box 58 forms a first transfer location 5 where the milled-off material is transferred from the milling drum 8 onto the first conveying device 14.
In the embodiment of
The conveying device 14 is mounted in a shaft 9 of the engine frame 2, which is preferably arranged centrally, and is adapted to be easily dismounted from the band shoe 50 for maintenance purposes and to be removed through the shaft 9.
The conveying device 14 with the conveyor belt 15 comprises a hood 22 forming, together with the upper carrying run 15a of the conveyor belt 15, a duct section 16a of a duct 16 extending from the drum box 56 to the end of the second conveying device 18. As can be seen in detail in the cross section of
Likewise, the second conveying device 18 is provided with a hood 26 also sealed with respect to the carrying run of the band conveyor 19 via sealing lips 46 and mounted at corresponding hood supports 44. Thus, the duct 16 is sealed in a dust- and gas-tight manner with respect to the surroundings.
In the upper region of the hood 22 near the discharge end but at a distance thereto, the hood 22 of the first conveying device 14 comprises a connection piece 23 projecting substantially vertically upward, to which a suction duct 24 is connectible. To this end, the engine frame 2 comprises a substantially vertical shaft 25 in its center through which shaft the suction channel 24 can come out upward from the engine frame 2. In a first section of the suction duct 24, an axial fan 28 is integrated in the suction duct 24. This has the advantage that the room required for a blower is minimized. The axial fan 28 permits a high air output and therefore, it generates a correspondingly high negative pressure in the first duct section 16a and the drum box 56 surrounding the milling drum 8. Therefore, the dusts and fumes produced during the milling process are sucked off reliably and with high efficiency via the suction duct 24. In the region of the first transfer location 5, i.e., at the lower end of the hood 22 and at the passage opening 56 of the drum box 58 and the band shoe 50, respectively, flexible rubber mats may circumferentially seal the transfer location 5. Smaller leakages of the drum box 56 or between the duct 16 and the drum box 56 are unimportant since, due to the negative pressure, polluted air cannot escape but at most, air is sucked in from the environment. As can be seen best from
To seal the first duct section 16a as well as possible at its upper end, the flaps 36 are provided with slots. Preferably, several flaps 36 are arranged behind each other to achieve an improved air sealing between the duct sections 16a,16b.
As can be seen best in
At the upper end of the conveying device 14, the milled-off material 3 is transferred into a receiving funnel 35 of the second conveying device 18 at the second transfer location 7, whereby the milled-off material 3 is transported over the conveyor belt 19 to the discharge end and disposed of onto the transport vehicle 10.
The transition location at the transfer location 7 is enclosed by sealing means consisting of flexible mats 30 so that the first conveying device 14 and the second conveying device 18 form a circumferentially sealed duct 16 that is continuous in the direction in which the material is conveyed.
At its other end, the suction duct 24 is connected to the hood 26 of the second conveying device 18, the connection piece 27 preferably entering into the duct section 16b at a low angle to produce an injection effect in the duct section 16b at the high flow speed of the sucked-off polluted air, whereby the lower portion of the duct section 16b is sucked as well. To permit an airflow, gaps for sucking air can be left free at suitable sites in the region of the second transfer location 7, e.g., at the sealing means 30. At the upper end of the second conveying device 18, the milled-off material is thrown off, the sucked-off air loaded with dust and fumes with the milled-off material 6 being disposed of together with the milled-off material 3. At the discharge end of the second conveying device, an agglomeration means 34 is preferably provided by means of which dusts can be bound and possibly existing fumes can be condensed. The agglomeration means 34 may consist of a water spraying means, the dusts and fumes being segregated, for example, with a spray. Preferably, the agglomeration means 34 is arranged outside the duct section 16b at the discharge end of the second conveying device 18, but it could also be arranged within the second duct section 16b.
The milling machine 1, however, could also be used without an agglomeration means 34 since the dusts and fumes are disposed of very far from the driver stand so that the working conditions on the driver stand and in the working area about the machine are considerably improved even without an agglomeration means 34.
As can be seen from
Compared with the embodiment of
Although a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the apparatus without departing from the spirit and scope of the invention, as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102 23 819 | May 2002 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP03/04691 | 5/6/2003 | WO | 00 | 11/16/2004 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO03/100172 | 12/4/2003 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 1459968 | Bailly | Jun 1923 | A |
| 4561145 | Latham | Dec 1985 | A |
| 5092658 | Smith | Mar 1992 | A |
| 5215071 | Mertes et al. | Jun 1993 | A |
| 5605381 | Schmoock et al. | Feb 1997 | A |
| 6195837 | Vanderlinden | Mar 2001 | B1 |
| 6210071 | McSharry | Apr 2001 | B1 |
| 6296318 | Simons et al. | Oct 2001 | B1 |
| 6733086 | McSharry et al. | May 2004 | B1 |
| Number | Date | Country |
|---|---|---|
| 34 05 473 | Oct 1985 | DE |
| 38 31 161 | Sep 1988 | DE |
| 39 03 482 | Aug 1990 | DE |
| Number | Date | Country | |
|---|---|---|---|
| 20050179308 A1 | Aug 2005 | US |
