Patent Publication Number: US-2020291584-A1

Title: System for producing hot mix asphalt

Description:
FIELD OF THE DISCLOSURE 
     The disclosure generally relates to asphalt production. More particularly the disclosure generally relates to portable methods and systems for producing asphalt. 
     BACKGROUND OF THE DISCLOSURE 
     Currently, the manufacture of plants consists basically of a mobile semi-trailer, and demand stems essentially from the need to move the equipment. Since all the systems required for the production of bituminous concrete are arranged on wheel sets, mobile equipment sets need several approvals from inspection bodies for transit on land routes. The change from the transport position to the working position is typically done with hydraulic cylinders, manually and with the use of a winch truck. However, the practicality of being a self-transportable option, whether it is a trailer or a self-propelled vehicle, depends on legal regulations for large and/or long vehicles traveling on highways. 
     Therefore, improved moveable systems for producing hot mix asphalt are needed. 
     SUMMARY OF THE DISCLOSURE 
     Therefore, due to considerations pertinent to the state discussed above, one of the goals of the present disclosure described here is to present a hot mix asphalt plant mounted on a single chassis that is easy to transport and does not depend on the legal regulations required for the transport of this type equipment. 
     For this, a constructive arrangement has been developed for hot mix asphalt plants comprising all components necessary for the production of asphalt on a single fixed chassis with dimensions required for transport in a 40-foot sea container (e.g., an open top high cube), that is, it is considered as a small size plant. 
     With a production rate of up to 30 Ton./h it has a constructive arrangement aiming to serve numerous world markets, facilitating transport and avoiding the national and international transportation legislation approvals. 
     The following summary for the disclosure refers to the development of a hot mix asphalt plant mounted on a single fixed chassis ( 1 ) with the correct dimensions for transport in a single maritime container (may also be referred to as shipping container) ( 8 ); on this tubular structure chassis, two individual dosing silos fixed to the chassis and supported on metering conveyor(s), a rotary dryer, a two-axle pug mill mixer, an enclosed burner, a fuel pipe, bituminous binder tubing, exhaust pipe, bag filter, drag elevator and a control cabin are disposed. 
     The following descriptive report for the disclosure refers to the development of a hot mix asphalt plant mounted on a single fixed chassis with the correct dimensions for transportation in a single shipping container; the chassis will be of tubular structure, with two individual dosing silos fixed to the chassis and supported on dosing conveyor(s), a rotary dryer, a two-axle pug mill mixer, an enclosed burner, fuel pipe, bituminous binder tubing, exhaust pipe, bag filter, drag lift and a control cabin. 
     A system for producing hot mix asphalt, comprising a hot mix asphalt plant is disclosed. The hot mix asphalt plant may include a chassis, a first and a second individual dosing silo, metering conveyor(s), a rotary dryer, a two-axle plug mill mixer, a drag elevator, and a control cabin, which may be configured to control the hot mix asphalt plant. The first and second individual dosing silos, the metering conveyor(s), the rotary dryer, the two-axle plug mill mixer, the drag elevator, and control cabin may be mounted on the chassis. The hot mix asphalt plant may be configured for transport in, for example, a maritime container, i.e., having overall outer dimensions for the entire assembly configured such that the entire assembly can fit within a maritime container. 
     The chassis may have a tubular structure, and may be a single fixed chassis. 
     The first and second individual dosing silos may be supported on the metering conveyor(s), and may be fixed to the chassis. The first and second individual dosing silos may be configured to supply one or more aggregates. 
     The rotary dryer may be configured to dry the one or more aggregates. The rotary dryer may have a burner, which may be supplied by a fuel pipe. The burner may be connected to an exhaust pipe, which may have a bag filter. 
     The two-axle plug mill mixer may be connected to a bituminous binder tubing, which may inject a bitumen into one or more aggregates. 
     The drag elevator may be disposed below the first and second dosing silos. The drag elevator may have a synchronizer gear system for one or more mixer shafts, and the drag elevator may be configured to egress the hot mix asphalt. 
     In this way, a system for producing hot mix asphalt comprising a hot mix asphalt plant designed to fit within a maritime shipping container is provided. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       For a fuller understanding of the nature and objects of the disclosure, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an embodiment of a plant inside a container; 
         FIG. 2  is an embodiment of a plant inside a container; and 
         FIG. 3  is an embodiment of a plant inside a container, in a ready-to-transport configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Although claimed subject matter will be described in terms of certain embodiments, other embodiments, including embodiments that do not provide all of the benefits and features set forth herein, are also within the scope of this disclosure. Various structural, logical, process step, and electronic changes may be made without departing from the scope of the disclosure. Accordingly, the scope of the disclosure is defined only by reference to the appended claims. 
     The characterization of the present disclosure may be made by means of representative drawings of a hot mix asphalt plant mounted on a single fixed chassis for transport in a single container, in such a way that the product may be fully reproduced using the suitable techniques, allowing characterization of the functionality of the object sought. The container may be a maritime container. 
     Such drawings are merely illustrative. Other embodiments are possible. 
     Embodiments disclosed herein disclose a system for producing hot mix asphalt, which includes a hot mix asphalt plant, which is sometimes referred to as a “plant.” Referring to  FIGS. 1-3 , the plant may encompass: a chassis having a tubular structure ( 1 ); two individual dosing silos ( 2 ) and ( 3 ) fixed to the chassis ( 1 ) supported on metering conveyor(s) ( 4 ), which may also be referred to as dosing conveyor(s) or conveyor belt(s); a rotary dryer ( 5 ), which may also be referred to as an aggregate dryer; a two-axle pug mill mixer; an enclosed burner ( 6 ); fuel pipe; bituminous binder tubing; exhaust pipe ( 9 ); bag filter ( 7 ); drag elevator ( 12 ), which may also be referred to as a drag lift; a control cabin ( 11 ); and compressor ( 10 ). Some embodiments may have one media conveyor ( 4 ). Other embodiments may have more than one media conveyor ( 4 ). 
     The dosing silos ( 2 ,  3 ) may be responsible for adding the aggregates that can be used in the preparation of the final product. The dosing silos ( 2 ,  3 ) may be fixed to the chassis ( 1 ), in an inverted pyramid shape. The dosing silos ( 2 ,  3 ) may be supported on metering conveyor(s) ( 4 ) that may unload the aggregates onto metering conveyor(s), which may then unload the material into the rotary dryer ( 5 ). 
     The rotary dryer ( 5 ) can comprise a cylindrical structure that is supported by rollers that, when in contact with the ring of the rotary dryer ( 5 ), can promote the rotation of the structure. 
     The rotary dryer ( 5 ) may have a set of fins on the inner surface to promote the drying of the aggregates. 
     The aggregates may be placed in a drying zone, where they can receive thermal energy from the burner ( 6 ). The exhaust of the gases derived from the combustion process of the burner may be carried out by an exhaust fan, through a bag filter ( 7 ). The bag filter ( 7 ) may be configured such that the exhaust system, for example, emits less than 20 mg/Nm 3  of impurities to the environment, thereby meeting the standards of particulate emissions. 
     The mixer may operate with two rotary blade shafts that are driven through a set of gear motors that may be synchronized via a gearbox. The mixture of aggregates from the dryer ( 5 ), the particulate recovered from the bag filter ( 7 ), and the bitumen may be incorporated or combined. The asphalt mass may then be directed through an outlet chute to a drag elevator ( 12 ) where it may be transported to a discharge silo. 
     With the virgin rock material previously selected, the asphalt mass production process may begin with the dosing of these aggregates, after the wet virgin rock material is sent to the rotary dryer ( 5 ) through metering conveyor(s) ( 4 ). 
     In this plant, a burner ( 6 ) may be installed in the region opposite to the entrance of the material. The rotary dryer ( 5 ), through the drying fins, may add heat transfer to the material. 
     After drying and heating the material, it may be sent to a two-axle pug mill mixer. Bitumen injection may then take place, resulting in Hot Mix Asphalt (HMA). 
     After the process, the asphalt mass may be unloaded into trucks or storage silos through a drag elevator ( 12 ). The combustion gases from the burner ( 6 ), which may be stored inside the rotary dryer ( 5 ) together with fine granular material, may be directed through an exhaust pipe ( 9 ) to the bag filter ( 7 ) with the aid of an exhaust fan. The bag filter ( 7 ) may serve the purpose of preventing this material from being released into the atmosphere, so it may be incorporated to the mixer with the aid of an auger. 
     This whole process may occur on a single chassis ( 1 ). The single chassis ( 1 ) may be configured to have the external dimensions so that it may be transported in, for example, a maritime container ( 8 ). The plant may be configured such that control of all the processes may be done via a control cabin ( 11 ). 
     All control of the asphalt plant may be done in a control cabin ( 11 ). The plant that has the external dimensions to be able to be transported in a maritime container ( 8 ) may also be done via a control cabin ( 11 ). The control cabin ( 11 ) may have interface software, and the control cabin ( 11 ) may be insulated acoustically and thermally. 
     The steps of the method described in the various embodiments and examples disclosed herein are sufficient to carry out the methods of the present invention. Thus, in an embodiment, the method consists essentially of a combination of the steps of the methods disclosed herein. In another embodiment, the method consists of such steps. 
     Although the present disclosure has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present disclosure may be made without departing from the scope of the present disclosure. Hence, the present disclosure is deemed limited only by the appended claims and the reasonable interpretation thereof.