Plant for producing bituminous conglomerate in continuous work cycle

Abstract

 The invention refers to a closed operative plant consists of a cylindrical rotary kiln (6-7) with upper filtering unit (34) for the smokes to be used for producing bituminous conglomerate. Said cylindrical kiln with initial part of smaller diameter (6), forming the drying chamber (16), and subsequent part of larger diameter (7), forming the combustion chamber (17), foresees in its inner a cylindrical structure (21) with fixed duct, brought on header (22), which lets in the heat flow from the burner (32) to the combustion chamber (17) countercurrent compared to the direction of advancement of the inert product. Inside the cylindrical kiln is then foreseen a mixing chamber (23) formed by a closed unit lying behind the wall where is placed the inlet of the heat flow.
Moreover it is foreseen the unloading of the product ready to be used from the mixing chamber (23) by means of three hydraulic cylinder (28) which open a set of equidistant portholes (29). The filtering unit consists of a closed cycle realizing the blasting of the smokes purified by means of fabric filters (37). The purifies air is then unloaded outdoor passing through a stack 40 using an intake manifolt (38) with air propeller (39). Moreover it is foreseen the coming into che mixing chamber (23) of the recovery fine dust of cement together with nonasphaltic road oil at 140°, coming from a feeder by means of a duct (25), and with other material made by fine dust of cement acting as binder coming from a screw conveyor (26) coaxially placed around the duct (25).

Description

[0001] The invention refers to a closed operative plant consists of a cylindrical rotary kiln and of a filtering unit for the smokes to be used for producing bituminous conglomerate in continuous work cycle. Said cylindrical kiln with initial part of smaller diameter, forming the drying chamber, and subsequent part of larger diameter foresees in its inner a cylindrical structure with fixed duct, brought on header, which lets in the heat flow from the burner to the combustion chamber countercurrent compared to the direction of advancement of the inert product. Inside the cylindrical kiln is then foreseen a mixing chamber consists of a closed unit lying behind the wall where is placed the inlet of the heat flow. Moreover it is foreseen the unloading of the product ready to be used from the mixing chamber of the kiln to a programmed time. The filtering unit consists of a closed cycle realizing the blasting of the smokes with continuous unloading towards outside of the purified air. Said filtering unit makes the completly recovery and dosing of the fine dust of the cement suspended in the air flow for its prompt use into the mixing chamber. Moreover the filtering unit foreseen a closed work cycle permits the complete use of the heat flow. Plants are known, as for instance the plant described and shown in the Italian Patent Application filed on 20th december 1991 with application number BO91A 000487. In comparison with said plant the invented plant foreseen the heat flow countercurrent compared to the direction of advancement of the inert product into the drying and combustion chambers permits, for impact, to increase the heat exchange effect so assuring a better yield of the kiln. Being the combustion chamber foresees in a closed unit, this permits by the different placing of the unit generating the heat flow, it is avoided the product volatization in particular of the fine dust of the cement and it is permitted to keep the product mixing to a right dosing. The invented cylindrical kiln with its initial part of smaller diameter, contrary to the kiln described in the Italian Patent Application BO91A 000487 foresees with an unchanged diameter, permits to foresee the widths of the drying and combustion chambers related to the use necessities; this considering that into the drying chamber is prevalently necessary to move the product onto the wall to increase the licking up effect while into the combustion chamber is prevalent the necessity to bring the product onto the heat source. In the plant described in the Italian Patent Application BO91A 000487 the unloading of the product ready to be used from the mixing chamber is actuated in continuous way according to fortuitousness so determing heterogeneous product. In the invented plant are foreseen programmed times for the unloading so avoiding heterogeneous product.

[0002] Moreover the invented plant permits the complete recovery and dosing of the fine dust of cement for its prompt re-employment. Being foreseen in the present invention into a closed operative plant, oppurtunately insulated, a filtering unit acting following to a cylindrical rotary kiln it is possible to realize the blasting of the smokes present into the circulation air and also to realize the complete use of the plant heat. Moreover being actuated the feeding of the bitumen in the mixing chamber, where there is not a circulation flow, it is avoided the dispersion of the same bitumen and consequently it is avoided the air pollution.

[0003] Is is foreseen a closed operative plant consists of a cylindrical rotary kiln in continuous cycle with upper filtering unit, said plant brought on a frame with three bridges 1 completed with a bearing network structure 2. Said structure 2 foresees beams 3, slanting towards the unloading, which bring on couple of rotary bearings 4 with rollers 5 a cylindrical kiln with initial part of smaller diameter 6 and subsequent part of larger diameter 7. Said cylindrical kiln foresees emerging on its outside rims 8 for the contact of the rollers 5 with motion gives by a motor 9 which transmits on the gear 10 of the rotary support 11 to the rack 12. The inert product, after to have being dosed, form the elevator 13, through the inlet 14 foreseen on the transversal fixed wall 15, coming into the drying chamber 16 formed by the initial part of smaller diameter 6 of the cylindrical kiln. In said drying chamber the product, in continuous movement by means of sets of vanes, proceeds gradually from gravity effect and it passes into the combustion chamber 17 formed by the subsequent part of larger diameter 7 of the cylindrical kiln. At the end of said combustion chamber the product climbs on a rotary elevator equipped with a set of vanes 18 radially placed on the circular crown 19 emerging from the cylindrical kiln 6-7. Said crown 19 rotates together with the kiln and it forms, with the inner circular fixed part 20 brought centrally by a cylindrical structure 21 housing into the fixed frame 22 sets out on the network structure 2, an orifice plate which devides the combustion chamber from the subsequent mixing chamber 23. The inert product, after to have being dryed into the drying chamber 16 and to have being baked into the combustion chamber 17, chimbs by means of the set of vanes 18 and it is unloaded in continuous work cycle by means of the chute 24 into the mixing chamber 23. In said mixing chamber, through a duct 25, is let in nonasphaltic road oil at 140° coming from a feeder. Contemporary through a screw conveyor 26, coaxially placed around the duct 25, is unloaded into the mixing chamber 23 other material made by fine dust of cement coming from an other feeder and acting as binder. The mixing is facilitated by sets of vanes 27 placed in parallel on the wall mixing chamber 23. To better mix the product it is foreseen its intermittent unloading. The intermitted unloading is actuated by three hydraulic cylinders 28 equipped with timers for regulating the operate times.

[0004] The hydraulic cylinders 28 open a set of equidistant portholes 29 for the unloading of the product ready to be used which proceeds in continuous and is unloaded through the opening 30 of the hopper 31. The product going out from the hopper 31 can then be loaded on transport means or used for the different necessities. The cylindrical rotary kiln 6-7 uses a burner 32 which, through a duct foreseen into the cylindrical structure 21, lets in the flame into the cylindrical kiln through the month 33 creating a heat flow countercurrent compared to the material advancing into the drying chamber 16 and into the combustion chamber 17. Upper to the cylindrical kiln, always supported by the network structure 2, is foreseen a parallelepipedal filtering unit 34 with separators 35 which divide the inside space in sectors 36 equipped with sets of fabric filters 37. Is is foreseen the use of an intake manifold 38 with an air propeller 39 for the outdoor getting out of the air purified by smokes through the stack 40. With the inert product into the combustion chamber 17 run into the heat jet coming out from the mouth 33, through the collector 41 housing into the header 42, the smokes sucked up by the air propeller 39 pass into an upper duct 43 and coming into a pre-separator 44. Said smokes then arrive into the chamber 45 where, going through the fabric filter 37, are purified. The purified air goes out from the duct 46 and through the intake manifold 38 by the air propeller 39 goes out from the stack 40. The dusts which have being kept into the fabric filters 37 fall into the cone-shape duct 47 with at its end the Archimedes' screw 48. Said Archimedes'screw 48 unloads the dusts into a duct 49 with a Archimedes'screw 50 where the load cells 51 of fine recovery product are weighed. The Archimedes'screw 50 then unloads the fine recovery product into the mixing chamber 23 through the screw conveyor 26. In this way is realized the prompt re-employment of the fine dust of cement dispelled into the plant. A version of the invented plant is illustrated in schematic view in the drawings of sheets 1, 2, 3 and 4. Fig. 1 is longitudinal section view of the plant in its initial part with view of the cylindrical kiln 6-7 and of the upper filtering unit 34. Fig. 2 is longitudinal section view of the plant in its end part with view of the mixing chamber 23. Fig. 3 is back view of the plant. Fig. 4 is side view of the plant with view of the frame with three bridges 1.

Claims

1. Plant for producing bituminous conglomerate in continuous work cycle foreseen a closed operative plant brought on a frame with three aligned bridges (1) completed with a bearing network structure (2) foreseen beams (3), slanting towards the unloading, which bring, on couple or roraty bearings (4) with rollers (5), a cylindrical rotary kiln (6-7) into which the inert product coming from an elevator (13) and upper to the cylindrical kiln foreseen, always supported by the network structure (2), a parallelepipedal filtering unit (34), characterized in that:

- the cylindrical kiln (6-7) consists of an initial part of smaller diameter (6) forming the drying chamber (16) and of a subsequent part of larger diameter (7) forming the combustion chamber (17); into said drying chamber (16) the product, moved by means of sets of vanes, proceeds for gravity effect to come into the combustion chamber (17) at the end of which the product climbs on a rotary elevator equipped with a set of vanes (18) and it is unloaded in continuous work cycle by means of a chute (24) into the mixing chamber (23) where through a duct (25) is let in nonasphaltic road oil at 140° and through a screw conveyor (26) is let in other material made of fine dust of cement and from which the product ready to be used is unloaded by means of a hopper (31);

- the cylindrical kiln (6-7) uses a burner (32) which, through a duct foreseen into a cylindrical structure (21), lets in the flame through a mouth (33) creating a heat flow countercurrent compared to the material advancing into the drying chamber (16) and into the combustion chamber (17);

- to better mix the product is foreseen its intermittent unloading to be actuated by three hydraulic cylinders (28) equipped with timers for regulating the operate times, said cylinders (28) open a set of equidistant portholes (29) for the unloading of the product ready to be used which proceeds in continuous way;

- the filtering unit (34) foresees separators (35) which divide. inside sectors (36) equipped with sets of fabric filters (37) and it foresees an intake manifold (38) with an air propeller (39) for the outdoor getting out of the air purified by smokes through a stack (40);

- it is realized the prompt re-employment of the fine dust of cement kept by the fabric filters (37) which falls into cone-shaped duct (47) with at its end the Archimedes'screw (48) which loads said dust into a duct with an Archimedes'screw (50) which through screw conveyor (26) re-put the dust into the mixing chamber.

2. Plant for producing bituminous conglomerate in continuous work cycle, as per claim 1), in that the cylindrical kiln (6-7) foresees emerging on its outside rims (8) for the contact of the rollers (5) with motion given by a motor (9) which transmits on gear (10) of the rotary support (11) to the rack (12).

3. Plant for producing bituminous conglomerate in continuous work cycle, as per claim 1), in that the set of vanes (18) is radially placed on the circular crown (19) emerging from the cylindrical kiln (6-7) and said crown (19) rotates together with the kiln to form, with the inner circular fixed part (20) brought centrally by a cylindrical structure (21) housing into the fixed frame (22) sets out on the network structure (2), an orifice plate which divides the combustion chamber (17) from the subsequent mixing chamber (23).

4. Plant for producing bituminous conglomerate in continuous work cycle, as per claim 1), in that the mixing into the mixing chamber (23) is facilitated by sets of vanes (27) placed in parallel on the wall mixing chamber (23).

5. Plant for producing bituminous conglomerate in continuous work cycle, as per claim 1), in that the product going out from the hopper (31) can then be loaded on transport means or used for the different necessities.

6. Plant for producing bituminous conglomerate in continuous work cycle, as per claim 1), in that with the inert product into the combustion chamber (17) run into the heat jet coming out from the mouth (33), through the collector (41), housing into the header (42), the smokes sucked up by the air propeller (39) pass into an upper duct (43), coming into a pre-separator (44) and then arrive into a chamber (45) where, going through the fabric filters (37), are purified.

7. Plant for producing bituminous conglomerate in continuous work cycle, as per claim 1), in that the last Archimedes'screw (48) unloads the dusts into a duct (49) with an Archimedes'screw (50) where the load cells (51) of fine recovery product are weighed.

Drawing