What Is Structure of Municipal Drum Type Asphalt Hot Mix Plant
Sep 20, 2023
The continuous drum type hot mix plant is mainly composed of a cold aggregate supply system, a drying drum, a continuous mixer (optional), a combustion system, a dust removal system, a finished asphalt storage bin, an asphalt supply system, a control system, etc. The continuous drum mix asphalt mixing plant is very different from the batch type asphalt mixing plant. It produces asphalt mix in a drum, which also continuously dries the aggregate.
Cold aggregate supply metering device
Since various materials of the continuous drum mixing equipment are continuously supplied and discharged, there is no secondary screening and metering device for aggregates, and the grading accuracy of the finished materials depends on the accuracy of the cold aggregate batching device.
In order to ensure the accuracy of the cold aggregate grading ratio, a metering device is set up between the aggregate belt behind the feeder and the aggregate conveyor. After the cold aggregates of various specifications are batched by the batching device, they are transported to the drying mixing drum by the weighing belt conveyor.
A vibrating screen can also be installed at the feed end of the weighing belt conveyor to prevent oversized stones from entering the drying mixing drum. The weighing belt conveyor simultaneously completes the transportation of cold aggregate and the weighing of the total mass of various grades of ingredients.
Drying and Mixing Drum
The appearance, internal structure, supporting burner, drum driving device, etc. of the drying mixing drum are similar to the drying drum of the asphalt batch plant. Their differences are as follows:
1. The heating device is located at the material feeding end of the drum, and the dust collection device is located at the discharge end of the drum. The material and the hot air flow flow in the same direction, that is, the drying of cold aggregate adopts the downstream heating method.
2. The drying, heating and mixing of cold aggregate with asphalt are completed in the drum at one time.
The drying mixing drum is divided into four process areas, with different blades along the length of the drum.
Burner and automatic adjustment device
The control system uses the computer to automatically adjust the oil-gas ratio of the burner through "feedforward" and "feedback" detection signals, thereby ensuring the mixing quality of the mixture.
Powder supply system
Stone powder is also measured continuously. The impeller feeder of the powder silo is connected to the weighing and measuring device. The continuously collected signals are processed by the microcomputer in the control room, and the system automatically changes the rotation speed of the feeder to adjust the supply amount.
How to add stone powder to drying drum
1. Use a screw conveyor to send the powder to the cold aggregate weighing belt conveyor, and then enter the drying mixing drum together with the cold aggregate. This method is simple and easy to implement, but if the wind speed in the drum is too high, the powder will easily be lost.
2. Another method is to use the pneumatic conveying method. It enters the drum from the discharge end through the pipeline, and its outlet is located below the outlet of the asphalt pipeline. Since the powder is adhered to the asphalt sprayed above after it is discharged from the tube, it is not easily blown away, but it is easy to agglomerate and difficult to mix evenly. Welcome to leave message below to inquire different types of municipal asphalt plants.