A hot mix asphalt plant (HMP) meets the needs of a wide range of projects, from small-scale maintenance projects to large-scale construction projects. These machines feature an extremely portable and compact design. With capacities up to 140 tonnes per hour and 50% RAP mixing capability, HMPs deliver the performance of full-size plants in a compact, mobile configuration. These machines are equipped with a variety of components to maximize mix quality while maintaining portability.
Components of an asphalt mixing plant
A typical asphalt mixing plant has several components that are essential for the production of asphalt. These components include a dry drum, asphalt batch mixer, and pre-drier. The dryer is an important part of the asphalt plant, as it helps remove moisture in the aggregates by heating them to a high temperature. The drying drum is also equipped with a burner unit, which helps to ensure an even temperature throughout the process.
Asphalt batch mixing plants are portable or stationary and are used to produce hot mix asphalt. They are usually designed to produce asphalt in batches, with different sized aggregates fed into separate feeder bins. Each feeder bin is powered by a variable-speed drive motor. The components of the batch plant are designed to maximize the quality of the asphalt mix while ensuring portability.
An asphalt mixing plant also features a bag filter unit for pollution control. Aggregates are fed to bins by size, with a conveyor conveying them to the drying drum. Most batch plants also have a secondary dust collector to separate dust from the mixture, and the aggregates are weighed before they are transferred to the mixing unit. The asphalt mixture is then mixed with liquid bitumen according to the specifications.
There are two types of asphalt mixing plants: batch plants and drum plants. Both batch and drum plants can produce varying types of asphalt. Batch plants can be easily switched between different mix recipes, while drum plants prepare asphalt through a continuous process. Drum plants need silos to temporarily store aggregate and liquid asphalt.
Process of producing hot mix asphalt
The process of producing hot mix asphalt involves mixing treated aggregate material with a bituminous binder. The bituminous binder improves the binding properties of the aggregate, making it more durable and water resistant. Organic dispersants are also used, which can increase the solids content of the mixture.
Asphalt is primarily composed of carbon-disulfide-soluble bitumen. Refined asphalt contains more than 99.5 percent carbon disulfide. The remaining impurities are inert. Nevertheless, it is possible for asphalt to foam, posing a hazard and compromising the material’s quality. Foaming asphalt can produce fumes and can be flammable. The temperature limit for asphalt to be flammable is 212 degrees Fahrenheit. This temperature level is significantly higher than what is required for typical paving operations.
When producing hot mix asphalt, several technologies have been developed to make it sturdier and more durable. Some are plant modifications, while others are additives added to the asphalt binder. The most common of these technologies is the “foaming process.” This technique involves injecting water into the hot asphalt binder when mixing it with aggregate. As the water turns to steam, the asphalt binder expands and turns into foam. The result is a mix that has 16 times the volume of conventional asphalt. The over asphalting process also helps in placement and compaction of the surface.
The process of producing hot mix asphalt involves mixing a mixture of asphalt cement and aggregate in a mixing facility. This process is used to produce hot asphalt and other materials. The aggregate is heated and proportioned in the facility. The facility may be permanent or portable. Some hot mix asphalt is produced in drum-mix facilities. Another method is batch-type hot-mixing. This method uses different sizes of hot aggregate drawn from storage bins.
Conveyors
Conveyors are an important part of any asphalt mixing plant. These systems move the various components of the plant, including the aggregate materials. Conveyor manufacturers, like CWMF, offer stock and made-to-order belt conveyor systems, which are customized to meet specific layout and production needs of each plant. Feeder conveyors are used to control the amount of aggregate to be conveyed through the plant. These systems use variable-speed belts to ensure that the correct proportion of aggregate is fed to the plant’s other components.
Conveyors for asphalt mixing plant are available for short and long-term storage of asphalt paving mix. Astec has a wide range of storage systems for this type of asphalt, including batchers, bucket elevators, and drag conveyors. They meet building codes and site-specific design criteria. They also help plant operators better manage the burner temperature, which reduces operating costs and emissions.
Conveyors for asphalt mixing plant are an essential part of an asphalt batch mixing plant. They move the materials from the batching chamber to the drums that are placed at various levels in the plant. During the mixing process, the materials are conveyed to the drums via a conveyor belt, which are equipped with conveyor rollers or a roller. In addition to conveyors, the plant requires other parts that contribute to its performance.
A properly installed asphalt mixing plant has a shelter to minimize its impact on the surrounding area. In addition to being secure, it is also space-saving. It also includes a stockyard and belt conveyors. In addition, the upper sections of the asphalt tanks are designed to serve as additive tanks. Other features of an asphalt mixing plant include a scavenging fan system to cover hot bins and vibrating screens. In addition, the floor chutes of batch towers can be easily cleaned with a broom.
Dryer
Dryer for asphalt mixing plant is used to create asphalt mixtures. The dry asphalt mixture produced in the plant can be easily loaded into a truck or a temporary storage container. This machine is also used for recycling of asphalt. To enhance the efficiency of the machine, it can be insulated to reduce fuel consumption. In addition, it has optional temperature probes that can be placed inside the silo pockets. It is also available with multiple coupled geared motors, which eliminates the need for linkage mechanism and reduces the part and maintenance cost. It also has easy-to-maintain wear parts.
Dryer for asphalt mixing plant is a multi-stage process. The dry aggregate is heated in an open flame burner that is installed at the upper end of the cylinder. Once heated, the aggregate is then sprayed by a spray mechanism that extends into the cylinder from the lower end. This spray mechanism then releases the heated bituminous liquid onto the aggregate as it flows through the cylinder. This spray forms a fine mist across the cross-section of the cylinder and falls into the aggregate as it passes through the device.
The dryer-mixer is connected to the asphalt plant through a mobile frame 23 that tilts the cylinder to control the speed at which the aggregate is passed through the dryer-mixer. Normally, the cylinder is inclined at an angle of two to seven degrees from horizontal. This angle is sufficient to move the aggregate from the upper inlet end to the lower outlet end and retain the particles for a certain time.
The efficiency of an asphalt mixing plant is directly related to its thermal efficiency. Improved thermal efficiency can reduce energy consumption and improve the quality of the finished product. Furthermore, it will also lower the operating cost of the asphalt mixing plant.
Drum mix plant
A Drum mix plant is a large-scale asphalt production equipment used in the construction and repair of roads. Its main part, the Thermodrum unit, uses the latest in internal flight design and heat transfer technology to produce the highest-quality asphalt mix. It also uses less fuel than conventional drum-mix plants, and its robust structure includes heavy-duty structural steel. These plants also have thrust wheels, which trap heavy-duty particles during the process.
The Drum mix plant for asphalt is a continuous mixer that heats aggregates and homogeneously mixes them with a specified amount of Bitumen and Filler. It then disperses the Hot Mix Asphalt into trucks and storage silos. A wide variety of capacities is available, from twenty to one hundred and twenty tons per hour, to suit different job requirements.
A Drum mix plant for asphalt is equipped with two types of pollution control devices, including a wet dust collector to trap the coarser particles in the hot asphalt. It also features a load-out conveyor to transfer the hot asphalt from the drum into a small hopper or storage silo. The asphalt can then be transported on trucks to construction sites.
The DM series plants have the latest AC drive technology and PLC module software based controls. These devices use a totalizer to display the set parameters. The totalizer displays bitumen and aggregate percentages, asphalt flow and filler flow, asphalt temperature, and output mix temperature. This allows you to monitor the quality of the mix as you work.
Drum mix plants are a cost-effective solution for asphalt production. The process is continuous, allowing you to produce a high-quality asphalt mixture. Drum mix plants are commonly used in towns and small cities and have the advantage of being cost-efficient.
