What Are The Components Of Asphalt Batch Mix Plant?

An asphalt batch mix plant is a device that intermittently mixes aggregates of different particle sizes, asphalt, and mineral powder in a specific ratio at a specific temperature to produce asphalt mixtures that meet quality requirements. It is widely used in highway, urban road, and airport construction projects.
 

The main components of asphalt batch mix plant include the following systems:
1. Cold Aggregate Supply System
Cold aggregate bins:
Used to store cold aggregates of different specifications. Generally, multiple independent bins are provided, each corresponding to a specific aggregate size to meet different mix proportions. The bins are typically made of steel and have discharge ports and regulating devices at the bottom to control the aggregate discharge speed.
Feeders:
Installed at the bottom of the cold aggregate bins, driven by a motor, they continuously and uniformly convey cold aggregates of different particle sizes to the belt conveyor according to a set ratio. Common feeders include vibrating feeders and belt feeders.
Belt conveyors:
Transport the cold aggregates from the feeders horizontally or inclined into the drying drum. It consists of a conveyor belt, drive drum, idlers, frame, etc., and features high conveying capacity and stable operation.
 

2. Drying and Heating System
Drying drum:
The core component of the drying and heating system, typically a tilted rotating cylinder. Cold aggregate is moved forward by the rotation inside the drum, exchanging heat with the high-temperature hot airflow generated by the burner, thus being dried and heated to the specified temperature. The inner wall of the drum is generally equipped with lifting plates to increase the contact area and time between the aggregate and the hot airflow, improving drying and heating efficiency.
Burner:
Provides the heat source for the drying drum. Common fuels include heavy oil, diesel, and natural gas. The burner generates a high-temperature flame and hot airflow by burning the fuel, which is injected into the drying drum to heat the aggregate. The performance of the burner directly affects the heating temperature and quality of the aggregate.
Dust removal system:
Used to collect and purify dust in the exhaust gas from the drying drum, reducing environmental pollution. Common dust removal equipment includes gravity dust collectors, cyclone dust collectors, and bag filters. Gravity dust collectors and cyclone dust collectors can initially remove large particles of dust from exhaust gas, while bag filters can further remove fine dust, ensuring that the emitted exhaust gas meets environmental standards.
 

3. Hot Material Lifting System
Elevator:
Lifts the dried and heated aggregate from the discharge port of the drying drum to the screening device. Elevators are generally bucket elevators, consisting of a traction chain, buckets, a drive unit, and a casing. Driven by the traction chain, the buckets lift the hot aggregate from the bottom to the top, and then discharge it into the screening device through the discharge port.
 

4. Screening System
Vibrating screen:
Screens the hot aggregate conveyed by the elevator, separating it into different particle sizes. Vibrating screens typically consist of a screen box, vibrators, springs, etc. The vibration of the vibrator causes the screen box to reciprocate, thus screening the aggregate on the screen surface. Aggregates of different particle sizes fall through corresponding screen openings into different hot material bins for storage.
 

5. Hot Aggregate Storage System
Hot aggregate silos:
Used to store hot aggregates of different particle sizes after screening. They typically consist of multiple independent silos, each corresponding to a specific aggregate size. The bottom of the hot aggregate silo has a discharge port and a metering device, allowing for precise control of the discharge rate of aggregates of various sizes according to production needs.
 

6. Powder Supply System
Powder silos:
Used to store powdery materials such as mineral powder. They are usually constructed of steel and equipped with a dust collection device at the top to prevent powder from escaping. The bottom of the powder silo is equipped with a screw conveyor or pneumatic conveying device to transport the powder to the powder metering device.
Screw conveyor:
A device that continuously transports powder using the rotation of screw blades. It has advantages such as simple structure, large conveying capacity, and good sealing. It can transport powder from the powder silo to the powder metering device, or it can transport the metered powder to the mixing pot.
Powder metering device:
Used to accurately measure the weight of the required powder. Generally, electronic metering devices are used, featuring high metering accuracy and good stability. The metering device precisely controls the amount of powder added according to the production formula requirements.
 

7. Asphalt Supply System
Asphalt tanks:
Used to store and heat asphalt. Generally, multiple tanks are provided to store different grades of asphalt. The asphalt tanks use heat transfer oil or steam heating to heat the asphalt to a specified temperature, ensuring good fluidity and adhesion.
Asphalt pumps:
Pumps asphalt from the asphalt tanks and deliver it to the asphalt metering device. Commonly used asphalt pumps include gear pumps and screw pumps, which feature high conveying capacity and stable pressure.
Asphalt metering device:
Used to accurately measure the required weight of asphalt. Also using electronic metering devices, it precisely controls the amount of asphalt added according to the production formula requirements.
 

8. Mixing System
Mixing pot:
The core component for asphalt batch mix plant, typically a twin-shaft forced mixing pot. The mixing pot contains two parallel and counter-rotating mixing shafts, each equipped with agitator blades. Hot aggregates, powders, and asphalt are uniformly mixed in the mixing pot to form an asphalt mixture that meets quality requirements.
Drive unit:
Provides power to the mixing shaft, enabling it to rotate at a set speed. The drive unit typically consists of a motor, reducer, and coupling, and features high transmission efficiency and stable operation.
 

9. Finished Material Storage and Unloading System
Finished material silo:
Used for temporary storage of the mixed asphalt mixture. It is generally constructed of steel with an internal insulation layer to reduce heat loss. The bottom of the silo has an unloading gate, which can be controlled pneumatically or electrically to unload the asphalt mixture into transport vehicles.
Unloading device:
Includes unloading hoppers and unloading belt conveyors, used to accurately unload the asphalt mixture from the finished material silo into transport vehicles. The unloading device generally has automatic positioning and metering functions, improving unloading efficiency and accuracy.
 

10. Control System
Control cabinet:
The control center of the entire asphalt batch mix plant, integrating various electrical control components and instruments, enabling centralized control and monitoring of all systems within the asphalt mixing plant. The control cabinet is equipped with operation buttons and a display screen. Operators can use these to start, stop, and set parameters of the asphalt mixing plant, and monitor its operating status in real time.
The PLC (Programmable Logic Controller):
It is the core component of the control system. Through programming, it enables automated control of various systems within the asphalt batch mix plant. The PLC can precisely control the operating time and sequence of each piece of equipment according to the production formula and process requirements, ensuring the quality and efficiency of asphalt mixture production.
Sensors and instruments:
These are used to monitor the operating parameters of various systems in the asphalt batch mix plant in real time, such as temperature, pressure, flow rate, and weight, and transmit the monitored signals to the PLC. The PLC automatically adjusts and controls the equipment based on these signals to ensure the stable operation of the asphalt batch mix plant.