What should be considered in operation of asphalt mixing plants?
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What should be considered in operation of asphalt mixing plants?
Release Time:2023-08-24
In asphalt pavement construction, Asphalt mixing plants play a key role. The performance and working conditions of the asphalt mixing plant directly affect the quality of the asphalt mixture, which is related to the quality of the entire project and the progress of the project.  Therefore, the current control technology of asphalt  plants is becoming more and more advanced, and the technological content is increasing day by day. This requires mechanical operators to continuously improve operational skills can meet the construction needs, ensure the normal operation of the machinery, exert its due effect, and ensure the quality and progress of the project. So how can we ensure the normal operation of the machine and give full play to its due effect?

First of all, the operator should be proficient in the structure and working principle of each part of the asphalt plant. On this basis, strictly control all production details, especially the metering system, because the quality of the metering work directly affects the quality of the asphaltThe technical index of the mixture.

  For the stone metering system, it should be noted that:
  (1) Keep each discharge door open and close flexibly and quickly;
  (2) Each discharge port shall be kept unimpeded and no sediment shall be allowed to ensure that the stone can flow down quickly and evenly during measurement;
  (3) Each discharge door should be closed in time and well sealed, and there should be no material leakage when the single material measurement is completed;
  (4) The area around the aggregate weighing hopper should be kept clean and there should be no foreign objects to prevent the bucket from getting stuck.
in a state of complete suspension;
  (5) Each aggregate weighing sensor should have a balanced preload, consistent force, and sensitive induction.

  For the powder metering system, the following points should be noted:
  (1) Keep the powder conveying pipeline unblocked and free from stagnation;
       (2) The feeder or valve should be tightly sealed, and there should be no powder leakage at the end of the measurement;
       (3) Frequently remove the dust and sundries on the powder metering hopper to keep it clean;
  (4) The entire metering system should be well sealed to prevent the powder from being damp and agglomerated;
  (5) The discharge of the powder scale must be complete, there must be no residual powder in the scale, the discharge door must be closed tightly, and there must be no powder leakage during measurement.

  For the bitumen metering system, pay attention to:
  (1) Before starting production, the pipeline should be fully heated to ensure that the asphalt temperature in the system reaches the specified value;
  (2) The asphalt spraying pipeline must be clean and smooth, and the nozzle part must not be blocked, otherwise the spraying will be uneven and the mixing effect will be affected;
  (3) The asphalt spray pump or opening valve must be closed tightly to ensure that there is no dripping after the asphalt spraying is completed;
  (4) The action of the bitumen metering switching valve should be accurate and timely, and the seal should be good, and the suspension of the bitumen metering barrel should be firm and flexible.
asphalt mixing plant operation_1asphalt mixing plant operation_2
  For the entire metering system of the asphalt mixing plant, the operator should check frequently. Check whether each weighing scale is completely suspended and whether there is any stagnation, check whether each weighing sensor is working normally, and whether the induction is sensitive. Regularly check to make the displayed value consistent with the actual value. If any problem is found, it should be solved in time to ensure that the metering system is always in good condition.
good working condition.

    Secondly, the operator should accumulate rich experience, be able to foresee most of the mechanical failures, and solve and eliminate hidden dangers as soon as possible. After a fault occurs, it should be able to accurately judge and eliminate it in time to ensure the normal use of the machine. To achieve this, the operator must do the following in addition to timely maintenance of the machinery according to the regulations:
  (1) The operator should patrol frequently, observe carefully, and carefully check the frequently moving parts. Check whether the joints are loose, whether the lubrication is good, whether the movement is flexible, whether there is abnormal wear, etc., and deal with the problems in time;
  (2) When the mixing station is in motion, listen with your ears, think with your heart, and find out every sound, if there is any abnormal sound. Find out the reason and deal with it properly;
  (3) Be good at distinguishing various smells. If the oil temperature is too high, the discharge temperature exceeds the limit, the circuit and electrical appliances are short-circuited and burned out, overheating caused by abnormal friction, electrical appliances and circuits are overloaded and cause serious heating, etc., all will emit different smells, through different smells, Partial failures are also foreseeable.
asphalt mixing plant operation_3asphalt mixing plant operation_4
  In short, the operator should pay attention to check the appearance, use various senses, and use different instruments to find out every abnormal change, analyze carefully, find out the cause, and find out hidden dangers. Due to the complex structure of the asphalt plant, there are various types of components, involving electrical and gas control systems, asphalt supply systems, combustion systems, metering systems, dust removal systems, etc. It is very difficult for an operator to master all parts in a short period of time, accurately judge and eliminate all faults. Therefore, if you want to be an excellent operator, you must observe carefully, think diligently, summarize carefully, and continuously accumulate experience.

  In addition to being proficient in equipment, operators should also have common sense of product quality control. That is to be familiar with the temperature, asphalt-stone ratio, gradation, etc. of the asphalt mixture, and to be able to skillfully make technical judgments on the mixture, and analyze and solve problems in the mixture in a timely manner.

  (1) Temperature control of the mixture: The temperature of the mixture is one of the standards for the qualification assessment of the mixture. If the temperature is too high or too low, it is waste and cannot be used. Therefore, how to control the temperature is one of the basic skills that the operator should have. Factors that affect the temperature of the mixture are the quality of the fuel. If the quality of the fuel is poor, the calorific value is low, and the combustion is insufficient, it will cause unstable heating of the stone, low temperature, and residues after combustion will remain in the mixture, seriously affecting the quality of the mixture. If the fuel viscosity is too high, the impurity content is high, and the water content is high. It will cause difficulty in ignition, blockage of pipes, and difficulty in controlling temperature; the moisture content of raw materials is another factor affecting temperature. The water content of the raw material is large and uneven. During the production process, the heating temperature of the stone is difficult to control. In addition, the technical status of the combustion system, the pressure of the fuel supply pump, and the amount of fuel injection are all related to the temperature of the mixture. The wear, air leakage, blockage and other failures of the combustion system make the parts unable to maintain the original performance, resulting in low system pressure, unstable oil supply, poor atomization combustion effect, and seriously affecting the stirring temperature. Therefore, experienced operators should be able to accurately judge the quality of fuel, the degree of dryness and humidity of raw materials, and the working conditions of the combustion system. Find problems and take corresponding measures in time. Although the current stirring equipment has the ability to automatically control the temperature, since it takes a process from the temperature detection to the addition and subtraction of the flame to adjust the temperature, the temperature control has a hysteresis. In order to ensure that the stirring temperature of the mixing station does not produce waste, the operator should carefully observe the temperature change rate and the temperature change result, and manually increase or decrease the flame or increase or decrease the feed amount to control the temperature change, so that the change result does not exceed Specified range, thereby reducing or eliminating waste.

  (2) The gradation control of the mixture: The gradation of the mixture directly affects the performance of the pavement. If the gradation of the mixture is unreasonable, the pavement will have some diseases such as large or small porosity, water permeability, rutting, etc., reducing The service life of the pavement seriously affects the quality of the project. Therefore, the gradation control of the mixture is also one of the skills that the operator must possess. Factors affecting the gradation of the mixture include: changes in the particle size of raw materials, changes in the screen of the mixing station, and the range of measurement errors. The particle size of the raw materials directly affects the gradation of the mixture. When the raw materials are found to have changed, the operator should cooperate with the laboratory to fine-tune the production mix ratio. The change of the hot material screen in the mixing station is an important factor affecting the gradation of the mixture. If the screen is blocked and the hot material is not screened sufficiently, the gradation will be finer. If the screen is broken, damaged, leaking, and the wear exceeds the limit , will make the gradation of the mixture coarser; the measurement error of the mixing station will also directly affect the gradation. If the measurement error range is adjusted too much, the deviation between the production mix ratio and the target mix ratio will be large, which will seriously affect the quality of the mixture. If the measurement error range is adjusted too small, the measurement time will be increased and the output will be affected, and the measurement will frequently exceed the limit, which will affect the normal operation of the mixing station. In short, the operator should pay close attention to the changes of raw materials, check the screen frequently, find problems and solve them in time, and adjust the measurement range to the best state according to the characteristics of the mixing station and other factors. Carefully consider other factors that affect the gradation, so as to ensure the mix ratio of the mixture.

  (3) Control of the asphalt-stone ratio of the mixture: The asphalt-stone ratio of the asphalt mixture is determined by the gradation of the mineral aggregate and the content of the powder. It is the fundamental guarantee for the strength of the road surface and its performance. Small will cause different diseases on the road surface.

  Therefore, strictly controlling the amount of asphalt is an important part of production control. Operators should pay attention to the following during production several aspects:

  During the operation, try to reduce the error range of asphalt measurement to make the measurement of asphalt as accurate as possible; the amount of additional powder also affects. Therefore, the measurement of powder should also be carefully controlled; according to the dust content of the fine aggregate, the opening of the induced draft fan should be adjusted reasonably so that the dust content in the mixture is within the design range.

  In modern construction, it is necessary to have advanced equipment to ensure the quality of the project, and at the same time must have good operating techniques to make the equipment fully utilize its advantages. Advanced asphalt plant equipment, advanced operation level, advanced management, unique products, and excellent quality. In order to ensure that the project is completed on time, with high quality and smooth.