DEVICE FOR PREPARING PAVING MATERIAL

Abstract: The invention relates to a device for preparing paving material, which is intended for the manufacture of hot paving materials. The device for preparing paving materials includes heating devices (13) for the aggregate and devices (10, 11, 12) for feeding the aggregate to the heating devices (13), as well as screening devices (14) and hot silos (17) for the screened aggregate. The device for preparing paving material also includes a batching bin (18) and mixing devices (19) for mixing the batch being moved from the batching bin (18) to form a ready-to-use paving material. The heating and screening devices (13, 14) are arranged to form a drum screen (15), which is supported on its own support members (16). The hot silos (17) and the batching bin (18) are arranged beneath the drum screen (15).

Description: DEVICE FOR PREPARING PAVING MATERIAL The present invention relates to a device for preparing paving material, which is intended for manufacturing hot paving materials with a final temperature of more than 140°C, such as particularly asphalt material, and which device for preparing paving material includes - devices (13) for heating the aggregate used as the raw material for the paving material and devices (10, 11, 12) for feeding the aggregate to the heating devices (13), - devices (14) for screening the heated aggregate and hot silos (17) for the screened aggregate, which hot silos are placed below the screening devices (14) , the aggregate heating and screening devices (13, 14) being arranged to rotate as an integrated drum screen (15) , which is supported on its own support members (16) , - a transfer vessel arranged after the hot silos (17) with attached measuring devices for determining the desired batch, and - mixing devices (19) for mixing the batch being moved with the requisite additives to form a ready-to-use paving material . Conventional devices for preparing asphalt are usually tower- like structures, which comprise an assembly of the necessary components for manufacturing paving material. The construction of the most widely known device for preparing asphalt, has first of all a feed funnel, from which the aggregate is fed to a separate heating drum. From the heating drum, a vertical elevator transfers the hot aggregate to a set of screens at the highest point in the device for preparing asphalt, through which the different grades of the aggregate drop into hot silos below the set of screens. In the hot silos, the aggregate remains hot and the various aggregate grades are batched according to a mix into a batching bin that lies in turn beneath. In addition to the aggregate, the requisite additives and filler powders are measured, usually separately close to the mixer. Finally, the batch is lowered into a mixer beneath the batching bin, in which the batch is mixed with bitumen to form ready-to-use paving material. From the mixer, the paving material is dropped into a vehicle beneath, to be taken to the point of use. In the device for preparing asphalt described above, all the components are placed on top of each other, so that the device for preparing asphalt material become very high. The high supporting structures then form a significant part of the total weight of the device for preparing asphalt. Such a tower-like structure can of course be dismantled and moved, but large cranes are required to handle the components . In other ways too assembly is slow and the various components must be fitted precisely in place. In the device for preparing asphalt described above, the aggregate must be raised to a considerable height, so that the vertical elevator becomes high. The transfer of the aggregate when it is hot also adds to the structural demands on the vertical elevator. In known devices for preparing asphalt, there are also fixed additive and filler bins, which must be detached from the support structure when it is moved. Devices with a low structure for preparing asphalt are also known and in other ways too differ considerably from the solution according to the preamble. A device for preparing paving material, which is formed from several components, is slow to erect, the erection requiring at least one high-powered crane with a wide reach. In addition, moving the dismantled components requires at great deal of transportation equipment. Similarly, patent DE1235972 discloses an apparatus, which includes a drum screen that is supported on its own support members. In addition, there are various silos beneath the screens. The entire apparatus is supported on a single support member, which makes it difficult, and even dangerous, to support the apparatus at a sufficient height. In addition, the measurement of the aggregate is imprecise and there is the further problem of a great deal of dust being produced when a belt conveyor is used. In addition, the capacity of the apparatus is insufficient nowadays. The invention is intended to create an entirely new type of device for preparing paving material, the total height of which is lower than previously and which can be erected more rapidly and easily, without separate cranes. The characteristic features of this invention are stated in the accompanying Claims. The components of the device for preparing paving material according to the invention are assembled as a few independent entities, the handling of which does not require special cranes. In addition, the various entities support themselves independently, so that conventional support structures are not required. The placing of the components eliminates unnecessary lifting of the aggregate, so that the energy consumption of the device for preparing paving material is also more economical than previously. In addition, when manufacturing paving material, the batch can be determined more simply and precisely than previously. By means of the device for preparing paving material according to the invention, it is also possible to make soft asphalt-concrete materials, which have a low mixing temperature (as low as 40 - 50°C) . It is then preferable to use a combined heating and screening apparatus for the aggregate, in which the aggregate feed and the burner are at the same end, which is the end opposite to the exit end of the screen, under which the hot silos are located. When the burner and the aggregate feed are at the same end, the high flame temperature of the burner will remove the moisture from the aggregate, even if the final temperature remains low. Later, the drier material is not liable to arching, even if the temperate drops below the condensation point. According to one preferred embodiment, the batching bin is also the transfer bin. In the following, the invention is examined in detail with reference to the accompanying drawings showing one application of the invention. Figure 1 shows a schematic drawing of the device for preparing paving material according to the invention, seen from above, Figure 2 shows the principal part of the device for preparing paving material according to the invention, seen from the side, Figure 3 shows a partial enlargement of the device for preparing paving material of Figure 4, as a partial cross-section, Figures 4a, 4b show the main components of the device for preparing paving material according to the invention, in the transportation position. The device shown in Figure 1 for preparing paving material according to the invention differs significantly from known tower-like and other devices for preparing asphalt. The construction of the device for preparing paving material is low and elongated. This reduces the lifting height required for the aggregate as much as possible and facilitates the erection of the device for preparing paving material . The device, according to the invention, for preparing paving material is particularly suited for manufacturing hot paving materials, such as asphalt, because the apparatus can be easily used to achieve a sufficiently high temperature. The final temperature of the ready-to-use asphalt material 'is usually more than 140°C. On the other hand, the device for preparing paving material can also be used for manufacturing other, and especially low- temperature paving materials. The aggregate required for manufacturing the paving material is first of all loaded, using some suitable means such as a wheeled loader (not shown) , into the feed funnel 10. From the feed funnel 10, the aggregate is transferred as a suitable flow of material, with the aid of a horizontal conveyor 11 and a vertical elevator 12, to the aggregate heating devices 13. Alternatively, the feed funnel can be connected directly to the vertical elevator or some other device can be used to feed the aggregate. According to the invention, in addition to the aggregate heating devices 13 , the screening devices 14 are also arranged to rotate as a suitable drum screen 15. Thus, after the drum screen 15, hot aggregate sorted into various grades is obtained. One preferred drum screen is disclosed in Finnish patent application number 990021, so that the construction and operation of the drum screen are not described in greater detail in this connection. In addition to the above, the drum screen 15 is supported on its own support member 16 at such a height that the hot silos 17 and batching bin 18 (Figures 2 and 3) can be placed beneath the drum screen 15. The next component beneath the hot silos 17 is the batching bin 18, into which an amount of aggregate according to the mix is batched from the hot silo 17. In connection with this, the requisite amount of additives and fillers are also added to the batching bin 18. The device for preparing paving material also includes mixing devices 19, which are, according to the invention, arranged together with the hot silos 17 and the batching bin 18, being supported as an entity separate from the drum screen 15. Thus, the device for preparing paving material can be erected considerably more easily and quickly than previously. Similarly, it is easier to erect the device for preparing paving material and to transport its components . Figure 2 shows most of the components of the device for preparing paving material. The figures clearly shows the support members 16 of the drum screen 15, which comprise telescopic support legs 16 ' . The drum screen 15 is arranged to be raised, by means of the support legs 16', from the transportation position to the operating position and to be set at the desired angle to the horizontal. The vertical elevator 12 can also be supported on the drum screen 15. In practice, the lifting height of the support legs 16' is 5 - 8, preferably 6 - 7 metres. Thus, both the hot silos 17 and the batching bin 18 can easily fit underneath the drum screen 15. In this case, the means for feeding the aggregate to the drum screen 15 thus include the feed funnel 10 with the horizontal conveyor 11 and the vertical elevator 12, which extends to the top end of the drum screen 15. This arrangement is preferred, because the lifting height of the vertical elevator is then 8 - 12, preferably 9 - 11 metres. In addition, the vertical elevator is used to move cold aggregate, so that the construction of the vertical elevator can be simpler than previously. At the same time, the durability of the vertical elevator is improved. The device according to the invention for preparing paving material is not only easy to erect, it is also easy to transport. According to Figure 2, the entity comprising the hot silos 17, the batching bin 18, and the mixing devices 19 is arranged as a trailer 20, which includes not only wheels 21 and a coupling member 22, but also support arms 23 for supporting the entity in the operating position. The trailer 23 also includes, for example, a control-room cabin 24 and the necessary auxiliary and safety devices. Figure 3 shows a cross- section of the hot silos 17, which are formed of hot silos. In the example of the apparatus, there are three actual hot silos, 25, 25', 25' ', and one dust silo 25' ' ' for the stone dust that is separated from the exhaust gas. The said hot silos form an entity that is supported to swing on the trailer 20 by means of the support frame 26 and a damped pivot axle 27. The ability to swing reduces the transfer height and makes it easier to fit the components together. Besides its low and compact construction, the operation in stages of the device, according to the invention, for preparing paving material is significant. When manufacturing paving material, the measured batch is transferred in one lot to the mixing devices 19. For this purpose, the device for preparing paving material includes a conveyor 28 (dragline) for transferring the batch from a lower position beneath the hot silos 17 to an upper position above the mixing devices 19. In addition, the conveyor member 28' of the conveyor 28 forms the batching bin 18 referred to above. This reduces both the number of transfers of the batches and the formation of dust from the aggregate. In addition, the operating principle of the conveyor connected to the entity formed by hot silos 17, the batching bin 18, and the mixing devices 19 is a bin with a backward and forward movement and equipped with a bottom hatch. In other words, the conveyor member forming the batching bin 18 moves in stages between the lower and upper positions. Batching of the paving material is started by dropping an amount of hot aggregate according to the mix from the hot silos 25, 25', and 25' '. At the same time, the necessary additives and fillers are added to the batching bin 18. Once the batch is ready, the batching bin 18 is raised to the upper position and the batch is dropped into the mixing devices 19. In order to determine the batch, scales forming measuring devices are arranged in the lower position of the conveyor member 28'. The scales can be arranged simply in connection with the batching bin 18 when it is stationary. In the mixing devices 19, the batch is mixed thoroughly and the amount of bitumen according to the mix is added to it, in which case the finished paving material can be finally dropped from the mixing devices 19 into a vehicle 35 below the device for preparing paving material . In Figure 2 , the batching bin in the upper position is shown by broken lines . The conveyor described is very easy to control and is quiet. The conveyor 28 includes only one conveyor member 28', which is moved between the lower and upper positions by means of a winch 29. In the figures, the guides 30 of the conveyor 28 are shown by broken lines . The conveyor according to the invention has few wearing parts and its construction is otherwise simple. Figures 4a and 4b show the principle components of the device according to the invention for preparing paving material in the transport position. Thanks to the support legs 16' in the drum screen 15, erection is simple. Alternatively, it can be equipped with support wheels and form a device that can be towed. The support legs 16' can also be used to load the drum screen 15 onto a vehicle. A vehicle can be driven between the support legs 16', which are set a suitable distance apart laterally, allowing the drum screen to be lowered onto the vehicle (not shown) . Finally, the support legs are turned to the horizontal position. Thus, a separate crane is not required to erect the drum screen. After erecting the drum screen, the trailer is brought under the drum screen and supported in the operating position by means of the support arms. Thus, this too does not require a separate crane. The trailer 20 can be transported by a conventional vehicle 35', as the transportation height is under 4,5 metres. Erection is also accelerated by the use of separate additive and filler powder bins. According to the invention, the additives and fillers are arranged to be stored in their own storage bins 31, from which connections 32 are then arranged to the batching bin 18, the mixing devices 19, or both. According to Figure 1, the filler is fed from the bin 31 directly to the batching bin 18, in which case the difference in height is advantageously small. Correspondingly, the bitumen is pumped from a second bin 31' directly to the mixing devices 19. To ensure correct batching, there are also scales 33 in the bitumen line 32'. In addition to the above, the device for preparing paving material also requires fuel, which is fed to the burner 34 directly from a tank 31' ' along a suitable pipe 32' ' . The device, according to the invention, for preparing paving material is considerably simpler than before. Thus its acquisition and operating costs are also lower than previously. Thanks to the low structure and the operation in stages, the transfers of material are as short as possible and the consumption of energy is small. The compact construction also facilitates the erection and transportation of the device for preparing paving material .

Claims: CLAIMS 1. A device for preparing paving material, which is intended for the manufacture of hot paving materials with a final temperature of more than 140°C, such as particularly asphalt materials, and which device for preparing paving materials includes - heating devices (13) for the aggregate used as a raw material of the paving material and devices (10, 11, 12) for feeding the aggregate to the heating devices (13), - screening devices (14) for the heated aggregate and hot silos (17) for the various grades of the screened aggregate, which hot silos are located beneath the screening devices and the aggregate heating and screening devices (13, 14) are arranged to rotate as a suitable drum screen (15) , which is supported on its own support members (16) , - a transfer bin arranged after the hot silos (17) with measuring devices connected to them for determining the desired batch, and - mixing devices (19) for mixing the batch being moved and the requisite additives to form a ready-to-use paving material, characterized in that the device for preparing paving material includes a conveyor (28) for moving the batch from a lower position beneath the hot silos (17) to an upper position above the mixing devices (19) , in which case the conveyor member (28') of the conveyor (28) forms the said transfer bin, which is also the batching bin (18) , in connection with which scales forming measuring devices are arranged in the lower position. 2. A device, according to Claim 1, for preparing paving material, characterized in that the support members (16) are formed by telescopic support legs (16'), by means of which the drum screen (15) is arranged to be raised from the transport position to the operating position and to be set at the desired angle in relation to the horizontal. 3. A device, according to Claim 1 or 2 , for preparing paving material, characterized in that it includes a combined apparatus (13, 14, 15) for heating and screening the aggregate, in which the feed and the burner (34) are at the same end, which is the opposite end to the screen's exit end, under which the hot silos (17) are located. 4. A device, according to any of Claims 1 - 3, for preparing paving material, characterized in that the devices for feeding the aggregate to the drum screen (15) comprise a feed funnel (10) with a horizontal conveyor (11) and a vertical elevator (12), which extends to the upper end of the drum screen (15) . 5. A device, according to Claim 4, for preparing paving material, characterized in that the lifting height of the vertical elevator (12) is 8 - 12, preferably 9 - 11 metres. 6. A device, according to any of Claims 1 - 5, for preparing paving material, characterized in that the entity, supported separately from the drum screen (15) , formed by the hot silos (17), the batching bin (18), and mixing devices (19), is arranged as a trailer (20) , which includes, in addition to wheels (21) and a coupling member (22), support arms (23) for supporting the entity in the operating position. 7. A device, according to Claim 6, for preparing paving material, characterized in that the hot silos (17) comprise hot silos (25, 25', 25 ' ' ) that are supported to swing by means of the support frame (26) of the trailer (20) and a pivot axle (27) . 8. A device, according to Claim 1, for preparing paving material, characterized in that the conveyor (28) connected to the entity formed by the hot silos (17) , the batching bin (18) , and the mixing devices (19) has the operating principle of a lifting bucket. 9. A device, according to any of Claims 1 - 8, for preparing paving material, characterized in that the additives and fillers are arranged to be stored in their own transportation devices (31) , from which a connection (32) is arranged to the batching bin (18) and/or to the mixing devices (19) •

Inventors: HAKKARAINEN KALEVI, HAKKARAINEN, KALEVI
Applicants: HAKKARAINEN KALEVI, HAKKARAINEN, KALEVI
Application year: 2001
Main classification: E01C19
IPC codes: E01C19