Asphalt mixing equipment is the first key equipment for asphalt pavement construction, and it is widely used. You may not know much about its technological process. Let's learn together.
Asphalt mixture mixing equipment is a factory-type complete equipment that mixes dry and heated aggregates of different particle sizes, fillers and asphalt into a uniform mixture at a specified temperature at a specified temperature. It is widely used in high-grade highways and urban roads. , Airports, docks, parking lots and other projects.
Usually asphalt concrete mixing equipment has two types of intermittent and continuous. The continuous process is simple and the equipment is simplified. Intermittent forced mixing equipment, due to the secondary screening of aggregates, various components are measured in batches, forced stirring and mixing, which can reliably guarantee gradation, and the measurement of powder and asphalt can also reach a very high accuracy; so mixing The quality of the asphalt mixture produced is good and can meet various construction requirements.
Since China currently mainly uses forced intermittent asphalt mixing equipment, the following content is mainly described by Sany Heavy Industry's LB series asphalt mixing equipment as a representative. 1. Process flow of mechanical system
The main process characteristics of the batch asphalt mixing equipment are: various ingredients are measured in batches, put into the mixer for forced mixing according to the preset sequence, and after the mixed finished product is discharged, the next cycle is formed to form Cyclic operation process. The so-called batch type refers to this mode of batch measurement and stirring production.
Use a loader to shovel sand and gravel materials of different specifications into the corresponding cold storage bin; controlled by the inverter (the inverter parameters are set in advance according to the gradation type, output and mix ratio) After the volume of the belt feeder is measured, the Feeding belt conveyor and feeding belt conveyor are transported to the drying drum.
The drying drum heats the sand and stone materials to a certain temperature by counter-current heating (the control system automatically adjusts the flame size of the burner). Due to the rotation of the roller, the sand and stone materials are repeatedly lifted and dropped by the blades in the cylinder to form a material curtain , The heat exchange effect is enhanced, and with the help of the inclination of the drum, the sand and stone materials continue to move forward while heating; after exiting from the drum, together with the coarse powder collected by the gravity dust collector, they are lifted and discharged by the hot aggregate elevator Into the hot aggregate screening machine.
The high-temperature dust-containing flue gas discharged from the drying drum first enters the gravity dust collector for preliminary purification through the first-level flue, and the collected powder with a particle size of 0.075mm or more is sent to the inlet of the hot aggregate elevator by the screw conveyor; then
The dusty flue gas enters the bag filter, and the filtered flue gas is directly discharged into the atmosphere by the induced draft fan. The dust recovered by the bag filter is sent to the recovered powder supply system for storage by the screw conveyor.
The hot aggregate sieve is divided into several specifications through a sieving machine, and flows into the corresponding hot material storage bins for storage. According to the set ratio, the aggregates of different specifications are batched into the stone measurement bin in order of small to large, and accumulated; the hot asphalt from the asphalt supply system and the powder from the powder supply system are separately According to the set ratio, put into the respective measuring device to measure. After the weighing is completed, it is put into the mixing pot according to the order set in advance for forced mixing. The agitated finished product is discharged into the finished material lifting trolley, lifted and discharged by the hoisting machine into the finished product silo for storage, or directly discharged into the material dump truck.
The control system relies on the signals detected by various sensors to monitor the material ratio, asphalt content, mixing material temperature and other important parameters in real time to ensure that the quality of the mixing material produced can meet the user's requirements. The electronic control system is also equipped with interlocking protection devices throughout the process to protect the equipment from accidental mechanical accidents.
It should be noted that the volume measurement of the cold aggregate through the belt feeder is a predicted amount, and the measurement of the sieved hot aggregate, powder and hot asphalt is an accurate measurement. Because of the secondary measurement, it can ensure the gradation of the mixture, and the ratio accuracy of aggregate, powder and asphalt is relatively high. At present, the static measurement accuracy of aggregates and powders does not exceed ± 0.5%, and the static measurement accuracy of asphalt does not exceed ± 0.25%. Because it is intermittent mixing, it is also very convenient to change the mix ratio of the mixture, and it is possible to change or replace the formula without stopping the machine.
