On the installation, use and management of large a

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Talking about the installation, use and management of large-scale asphalt mixing plant

Abstract: combined with the construction and production practice of large-scale asphalt mixing plant, this paper summarizes its installation technology, production and cost management, and provides reference opinions for the rational use and effective management of large-scale asphalt mixing plant

key words: large asphalt mixing plant; Installation; Technology; Production; Cost management

1. Introduction

with the continuous expansion and extension of China's traffic roads, the road construction equipment is also constantly developing and improving. In the construction of high-grade highway, asphalt concrete, as a kind of surface course material, is increasingly used by road designers, and asphalt mixing plant undertakes the mission of producing asphalt concrete

the speed of road construction is accelerating, and small and medium-sized asphalt mixing plants can no longer meet the needs of road construction. Ten years ago, the asphalt mixing plant with the output of 120t/h has gradually been driven out of the market competition stage, replaced by high-yield asphalt such as 360t/h and 400t/h until the movable part of the sample completely exposes the fixed part of the mixing plant, and they gradually become the mainstream products in the market

2. Installation of mixing plant

with the increase of the output of the asphalt mixing plant by pressing the start button, the structure of each part also increases accordingly. As a large machine, the foundation and equipment installation of the mixing plant should be paid great attention to

2.1 foundation and equipment installation

during the construction and production of asphalt mixing plant, the production of industrial noise and dust is inevitable. When selecting the site and considering the size of the site for installing the mixing plant, we must pay attention to that the asphalt plant should be as far away from residential areas and farmland as possible to avoid the impact of noise and dust pollution generated by the mixing plant on Residents' lives. Secondly, resource factors such as electricity and water resources should be considered

according to the geological conditions, the site selected for the asphalt mixing plant is divided into soft foundation and field. The field generally has relatively hard soil. After setting out and deep excavation, the concrete construction of the foundation can be carried out only by general bedding treatment of the bottom layer; For soft foundation geology, after setting out and excavation, we must carefully examine and study the degree of compaction after excavation, and then choose different treatment processes for foundation bottom reinforcement. Generally, plum blossom piles and pile casings are driven, or the area of the bottom foundation is increased to increase the bearing capacity of the foundation and prevent hidden dangers to the mixing plant equipment and production due to the cracking or sinking of the foundation in the future. In production, the vibrating screen, mixing cylinder and aggregate drying cylinder of the main part of the asphalt mixing plant are the components that produce the strongest vibration of the whole set of equipment. When we carry out foundation construction, we should pay attention to the foundation pouring of the main building and the aggregate drying cylinder, especially when the combined switch is turned to the vertical position, so as to eliminate the hidden dangers caused by human factors such as Jerry built construction and the foundation does not meet the flatness requirements. Long term mechanical resonance can make a M30 high-strength screw produce mechanical fatigue and directly break. Therefore, when installing the foundation, we must ensure that the same horizontal plane of the foundation does not exceed the range of ± 2cm of the elevation, so as to minimize the harm caused by equipment resonance

after many times of equipment disassembly and assembly practice, I believe that the following installation procedures are more feasible:

take the main building as the center and install it radially on three sides, so that the lifting task of large cranes can be completed in a short time while freeing up the land occupied by large objects, so as to save installation costs. In addition, if the mixing plant has installation sequence requirements, it should be installed according to its requirements

2.2 cable installation

with the continuous increase of the production of the mixing plant, the power consumption of the whole machine also increases. Now it generally reaches 600kW ~ 1000kW. The cross-sectional area of the power supply line is large. Coupled with the control elements, there are many control lines. Generally, cable trench wiring is used. Before wiring, we carefully check whether the cable is damaged to avoid short circuit or open circuit. When installing high-power motor cables, be sure to wrap the terminals with self-adhesive high-voltage tape to prevent the motor vibration connector from being ground short circuited after wearing through the tape, so as to avoid the risk of burning the motor

in the control system circuit, the signal screen closed cable must be connected in strict accordance with the requirements to reduce the impact of external electromagnetic interference on the control system. At the same time, pay attention to concealment and protection of the lines, and make safety protection warning signs. The circuit direction should be far away from the oil circuit and high-temperature and humid areas as far as possible to reduce the corrosion and aging of the wires. In the process of wiring, if you encounter some ambiguous wire markers that cannot be seen clearly, you must not be careless. Once you connect the wrong wire, it is possible to burn electrical components. It's best to put it down first, and then carefully check the circuit when the final debugging reaches that part, check for leaks and make up for deficiencies, and improve them one by one

3. Supporting management of production personnel

in addition to the seven systems of the main building, storage bin, powder supply, asphalt supply, aggregate supply, control system and dust removal system, there are many auxiliary components of the system. Once one of the components has problems, the whole asphalt mixing plant may be paralyzed. So many systems and components need to be maintained by various personnel with certain quality in each shift to ensure the normal operation of the mixing plant. After trying the personnel combination of several teams, we optimized the supporting personnel of each team, so as to not only effectively maintain production, but also control the overstaffed crew structure

the optimized personnel structure is roughly as follows (two shift system):

station master: responsible for overall coordination of various relations between the mixing plant and external departments, including work reporting and summary to the upper level

monitor: you need to have certain English reading and writing ability, have certain automation control knowledge and coordination ability, and be proficient in operating equipment

operator: understand basic mechanical principles, have basic electrical welding and repair skills, and be skilled in the operation of mixing equipment

electrician: have generator operation certificate, and master the control principle of strong current and electric drive

cooperate with workers: have certain basic mechanical knowledge, understand the working process of the mixing plant, cooperate with equipment management, and have a high working heart and enthusiasm

4. Production technology management

the control system of asphalt mixing plant is generally completed by the work server as the terminal industrial control computer and PLC, with a high degree of automation. In the production process, the machine operator should operate the machine in strict accordance with the operating instructions. It is forbidden to work without a license, illegally start and stop the server

before production, the crew on duty should carefully check the lubrication of the bearings at all parts, whether the oil circuit leaks, whether the protective switches and manual valves are in the correct position, whether the heating of the asphalt pump is sufficient, and whether the system parameters are within the allowable range. Only after making safety preparations can the whole machine be started and the machine be preheated

in order to save costs, heavy oil is generally used as the energy material to burn and heat the aggregate. However, because the heavy oil itself does not have the characteristics of ignition at room temperature, diesel must be used to support the combustion before preheating the machine. After the flame is stable, it can be converted into heated heavy oil. In order to obtain better fluidity and flash point, heavy oil is generally heated to 100 ~ 120 ℃

the preheating process of the cooler generally takes 10 ~ 15min. When the exhaust gas temperature of the bag dust collector reaches 90 ℃, the cold aggregate can be added after the moisture accumulated in the bag evaporates. Do not be too hasty. If the cold aggregate is heated when the moisture is still in the bag, the moisture and dust in the bag will stick together, which will block the air gap of the bag and affect the dust removal effect. During this period, you can work online between the server and the industrial computer, observe whether the connection between the server and the industrial computer is normal, and make preparations for production

after the server has set various parameters and production tasks, under the coordinated control of PLC and industrial computer, the production of asphalt mixing plant is an automatic assembly line operation process, from cold aggregate to hot material and then to the production of asphalt mixture, which can continuously complete various setting tasks until the end of the setting task

in this process, we must pay attention to observe the change of

(a) the current of each motor

(b) whether the aggregate temperature is within the allowable deviation range

(c) whether the supply of cold and hot silos is balanced

(d) whether the supply of powder asphalt is smooth

(E) whether each part of the machine operates normally and whether there is abnormal sound

(f) whether the receiving car queues up to receive materials as required

once any abnormal condition is found, the production task must be stopped immediately, and the production can be continued after the fault is eliminated

5. Cost control management

transportation vehicles are prone to waste mixture dumping in the process of loading and unloading mixtures The processing cost of a ton of asphalt mixture is generally fourorfive yuan. The more waste, the higher the cost of the project If there is a waste of 10t mixture in a day, and the construction period is 60 days, there may be a waste of 600t asphalt mixture, and the direct economic loss will reach more than 300000 yuan. Therefore, the cost control of asphalt mixing plant must first prevent the unnecessary waste of mixture, and a special vehicle commander can be set up

in the construction of engineering projects, a lot of energy materials are needed to heat the asphalt aggregate. Reasonable and effective control of this energy material can better reflect the value of cost saving

the automatic control combustion system of asphalt mixing plant has developed into a series of models, such as light diesel, heavy oil, pulverized coal, gas engine, oil-gas dual-purpose machine and so on. In our country, natural gas and coal are not very sufficient. Due to the special factors of its working conditions and use site, the road construction industry has been focusing on the use of fuel burning engines. In recent years, with the market factor of the rising price of light diesel oil, light diesel oil, as a traditional aggregate heating energy material, has been slowly replaced by low-cost heavy oil. In order to improve their competitiveness and achieve the purpose of cost saving, many asphalt mixing plant merchants and users have transformed and optimized the combustion system to adapt to the combustion of heavy oil

a good combustion engine can be budgeted. It needs about 8l/t to burn and heat the aggregate to 180 ℃. In order to achieve the same combustion value, the heavy oil is about 9 ~ 10L/T. for example, to produce 200000 tons of aggregate, the diesel oil is 4.26 yuan/l, and the cost is 6.816 million yuan, while the heavy oil is 3 yuan/l, and the cost is 5.4 ~ 6 million yuan. The project using heavy oil can save 816 ~ 1.416 million yuan, so the fuel oil can be reasonably selected under the condition of ensuring the stable operation of the equipment, It can increase the comprehensive benefit and minimize the production cost

before batch production of mixture in asphalt mixing plant, the temperature of mixing pot is low, and the first pot of mixture produced is often wasted due to low temperature, or several tons to more than ten tons of hot aggregate are discharged from the hot silo before it is officially put into production. This kind of wrong operation and waste is also a big taboo of cost control. After we have predicted this situation, we can first appropriately increase the temperature of hot aggregate, carry out manual mixing control, and slowly supply cold materials. After the production of 3 ~ 4 pots, the temperature of the mixing pot and the temperature of the hot silo rise, we can carry out mass production, so as to eliminate the innocent waste of raw materials. In addition, to optimize the production mix proportion, the accuracy of each weighing system involves cost control

6. Filing management of production materials

asphalt mixing plant is a group of machinery and electrical appliances

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