Scarifier with suction and handling device for dust

Abstract: The invention produces a dust handling device on a self-driven scarifier that includes a milling drum, a conveyor belt for the material broken up and an elevator belt. The device includes: a tunnel-like hood (5) covering at least the conveyor belt (3); a housing (4) enshrouding the milling drum (2; 21) and demarcating at least one suction area (9) located to the rear and top of the milling drum and covering the whole width of the drum, and two upper lateral areas (8; 8') that enfold said milling drum and that are connected with said suction area (9); a duct (10) that links said suction area (9) with the inlet (71) of a centrifugal fan (7); a centrifugal fan (7), with its outlet (74) connected to a filter (11) designed to withhold the solid components of the dust and fumes.

Description: The invention concerns a self-driven scarifier for road surfaces, comprising a device especially suitable for sucking up dust and fumes that are produced when removing the actual road surfaces. It is known that scarifiers are machines used to remove the surface asphalt that covers road courses. They basically involve a frame mounted on wheels, provided with a tractor engine, a driver's cab and at least one milling drum set against the road surface to be broken up. The milling drum is made to rotate and, by means of the protruding tines covering its circumference, it breaks up the road surface that it is set against and which it is made to break down into. The material resulting from said breaking up process can be recycled for subsequent uses and is therefore removed from the milling drum work area before continuing the digging. The most recent scarifiers are fitted with a conveyor belt that continuously collects the material resulting from breaking up the road surface, directly during the actual breaking up process, using the centrifugal force that the milling drum exerts on the material as it is being broken up. The conveyor belt then channels the material that has been broken up towards a second elevator belt that is part of an adjustable loader that allows the material to be fed into the body of a dump truck that drives alongside the scarifier while it is working. The broken up material can then be transported to a collection site, ready for subsequent reuse. One of the major problems found when using the aforementioned scarifiers is that a substantial quantity of bitumen dust and fumes are produced as a result of the enormous friction that the ripper equipment exerts on the asphalt surface to remove it completely. The cloud of dust and fumes mainly builds up around the work area, but it rapidly spreads upwards and along the two belts, especially around the conveyor, which collects and moves the material away from the milling drum. Therefore it is easy to understand the discomfort that the scarifier operator has to face while controlling this machine, both for aspects regarding inhalation of harmful, unhealthy dust-and fumes, and for the limited visibility created around the operations. A similar harmful environment and visual disturbance also affect the other workers assisting in the work of breaking up the road surface, not to mention passers-by that are more or less surrounded by clouds of dust and fumes raised by the machine. The problems of harmful dust have even worse effects when the scarifier's milling drum works on quarry faces for the production of cement components. This invention intends to prevent these damaging effects and overcome the inconveniences mentioned above. US-A-5 063 713 discloses a device for abrading road markings along a road surface and for collecting the particulate therefrom. The device includes a frame to which is appended a series of independently controllable abrading devices capable of independent actuation by an operator in an enclosed selectively positionable cab. The abraders are adapted to rotate along the road surface to be abraded and effectively grind the present road markings into particulate. Thereafter, the collection system consisting of a collection tube, bag house and disposal hopper creates a suction force through the system through the use of suction fan. Accordingly, the abrading particulate is drawn through the collection system into the bag house where it is filtered by internal suspended filters and is ultimately discharged through the use of an appended conveyor into hopper container portion. US-A-4 561 145 discloses an apparatus to be incorporated into a road planer that would sweep vacuum material not put onto the existing conveyor by the milling operation. This apparatus would route this material onto the existing conveyors in planing and milling machines. This apparatus may also be added to force feed loaders converting them to street sweepers. It is an object of the invention to produce a scarifier fitted with a means of sucking the harmful dust and fumes that are produced during the breaking up of road surfaces. Another object is that said dust and fumes should be channelled towards a means of filtering that withholds the harmful particles they contain, returning purified air to the atmosphere, not harmful to health. The above objects are achieved by a scarifier comprising a dust handling device in accordance with the main claim. Preferred embodiments of the present invention may be gathered from the dependent claims. According to a preferred embodiment of this invention, the dust suction and handling device is fitted with a centrifugal suction fan driven by a hydraulic motor and connected to a cyclone filter designed to withhold the harmful fumes and also separate the solid particles suspended in the dust. According to another embodiment of this invention, the centrifugal suction fan is driven by an electric motor, or by a pneumatic motor and the dust filter has a mesh construction. Additional characteristics and details of the invention shall be better illustrated in the description of the preferred embodiment of the scarifier, given as a guideline but not a limitation and illustrated in the attached diagrams, where: Fig. 1 shows a side view of the most commonly used scarifier according to the present invention; Fig. 2 shows the housing of the milling drum of the scarifier according to the present invention. With reference to the above figures, the present invention is applied to a scarifier 1 that has a milling drum 2 on its underside fitted with a plurality of protruding tines 21 covering its circumference designed to break up a road surface as wide as the drum itself. For this purpose, the milling drum is rotated by a suitable motor and causes the broken-up material to raise by throwing it by centrifugal force onto the conveyor belt 3 that is running in a continuous loop. The violent breaking up of the layer of road surface, that is achieved by the intruding and eroding friction of the drum's tines into the actual surface, also produces a substantial amount of bituminous dust and fumes that tend to quickly rise and spread in the surrounding atmosphere causing the inconveniences and disturbance mentioned earlier. The scarifier of the present invention prevents this diffusion by means of the housing 4 that covers the milling drum 2 over its front section, where there is the greatest turbulence, and is connected with the tunnel 5 that covers the conveyor belt 3 along its whole length towards the second elevator belt 13. Said tunnel 5 has louvers 51 along both side walls to suck in air from the outside so that the dust around the broken-up material on the conveyor belt is sucked up by the action of the centrifugal suction fan 7 in the housing 4. Said housing includes two lateral suction areas 8 and 8' along the milling drum's flat ends and at the top of the milling drum that overhang the front of the drum, and a suction area 9 central to its rear that connects through a funnelled section to the duct 10. Said duct channels the dust and fumes towards the centrifugal suction fan 7 that has a vertical branch 72 in line with its suction inlet 71 to collect free falling larger sized solid particles contained in the sucked dust. In order to prevent the continual suction of air by the suction fan through said vertical branch, the bottom of this branch is closed by a hatch 73 that is only opened under the weight of a pre-set quantity of deposited material, which is discharged onto the ground and the hatch 73 then returns shut immediately afterwards. The centrifugal suction fan 7 is preferably driven by a hydraulic motor, electrically controlled by the operation of the milling drum. This suction fan has its outlet 74 coupled to the inlet of the filter 11 that separates the solid particles still present in the dust, discharging them by gravity into a vertical chute 12 that has its bottom fitted with a tipping discharge hatch 121 similar to the one described above. In this way, the outlet flue 111 of the filter only gives off purified air, that is thereby of no harm to persons and the environment. The example illustrated in the attached diagram belongs to the most recent generation of scarifiers that incorporates a second elevator belt 13 on its front, belonging to a loader 14. Said loader can be adjusted in height to suit the position of a dump truck's body that proceeds before the scarifier and collects the broken-up material. In this case, a possibility should be provided to extend the tunnel-like hood 5 of the conveyor belt 3, to cover the length of the second elevator belt 13, joining together the two sections of the actual tunnel at the swivel section of the loader 14, by means of a cover 15 in elastic material or similar that withholds the dust and forces the sucked air to enter the tunnel primarily through the side louvers to increase its speed. Changes may be made in the construction details of the scarifier during its actual production. In particular, any kind of known centrifugal suction fan may be used, as long as it is suited to the purpose. In the same way, even a different type of filter may be used such as, for example, a cyclone separator or mesh filter.

Claims: A self-driven scarifier comprising a dust handling device, said scarifier comprising at least one milling drum, at least one conveyor belt for the broken-up material, said conveyor belt being adjacent to the milling drum, and an elevator belt to channel the material into a collection site, said dust handling device comprising a tunnel-like hood (5) covering at least the conveyor belt (3); a housing (4) enshrouding the milling drum (2; 21) and demarcating at least one suction area (9) located to the rear and top of said milling drum and covering the whole width of the drum and two upper lateral areas (8; 8') extending around said milling drum and being connected with said suction area (9); a filter (11) designed to withhold the solid components of the dust and fumes; a centrifugal fan (7) driven by means of motors, with its outlet (74) connected to said filter (11); and a duct (10) that links said suction area (9) with an inlet (71) of said centrifugal fan (7), wherein said tunnel-like hood (5) is connected to the housing (4) so that the dust around the broken-up material on the conveyor belt (3) is sucked up by the action of the centrifugal fan (7). The scarifier according to claim 1, wherein said tunnel-like hood (5) of the conveyor belt (3) also extends to cover the elevator belt (13), having two sections of cover connected together by means of elastic joints (15). The scarifier according to claims 1 or 2, wherein the tunnel-like hood (5) of the conveyor belt (3) has a plurality of louvers (51) along its side walls where the suction air of the centrifugal fan (7) enters. The scarifier according to any of the preceding claims, wherein the centrifugal suction fan (7) has a vertical chute (72) under its inlet (71), the bottom of said vertical chute (73) being fitted with a tipping hatch (73) that opens itself under the action of the weight of the larger sized solid particles sucked through the duct (10) connecting the housing (4). The scarifier according to any of the preceding claims, wherein the filter (11) communicates with a vertical chute (12) where the smaller solid particles deposit as they are separated by said filter, said chute being fitted with a hatch (121) that opens by weight. The scarifier according to any of the preceding claims, wherein the centrifugal fan is a centrifugal suction fan driven by a hydraulic motor and connected to a cyclone filter designed to withhold the harmful fumes and also separate the solid particles suspended in the dust. The scarifier according to any of claims 1 to 6, wherein the centrifugal fan is a centrifugal suction fan driven by an electric motor or by a pneumatic motor, and the dust filter has a mesh construction.

Inventors: BITELLI ROMOLO, BITELLI, ROMOLO
Applicants: BITELLI SPA, BITELLI S.P.A.
Application year: 1999
Main classification: E01C23
IPC codes: E01C23