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Asphalt Mixing Station Operation Management

AKW GROUP | Updated: Oct 18, 2017

During the construction of asphalt pavement, the asphalt mixing plant plays a key role, the performance of asphalt mixing plant and the working conditions of asphalt mixing plant, directly affect the quality of the asphalt mixture, it is related to the quality of the whole project, related to the progress of the whole project. So the current asphalt mixing station control technology is becoming more and more advanced, scientific and technological content increasing, which requires the mechanical operation personnel constantly improve the operating skills, to meet the needs of the construction, to ensure that mechanical function, play its due effect, to ensure the engineering quality, guarantee the construction schedule. So how can ensure machine to function normally, give full play its due effect.

First of all, the operator should be familiar with the structure and working principle of each part station, on this basis, strictly control each production details, especially the measurement system, because of working condition of the measurement is good or bad, directly affects the technical index of the asphalt mixture.

For the stoichiometric system, it should be noted that:

(1) keep the unloading doors open and close;

(2) the discharge opening shall be kept open, and no sediment shall be allowed. When the measurement is ensured, the stone shall be quickly and uniformly.

(3) the unloading doors should be closed in time and sealed well.

(4) the aggregates should be kept clean and should be kept clean, so as not to have foreign objects, so as to ensure that the bone material will be completely suspended.

(5) each aggregate weighing sensor, the prepressure should be balanced, the force should be consistent, and the sensor should be sensitive.

For the powder metering system, the following points should be noted:

(1) keep the powder conveying pipeline unimpeded and can not have a blocking phenomenon;

(2) feeder or valve shall be sealed strictly and the measurement ends; No leakage of powder;

(3) regularly remove dust and debris from the powder gauge and keep it clean;

(4) the whole metering system shall be sealed well to prevent the powder from being damped;

(5) the powder is said to be completely unloaded, and there must be no residual powder in it. The discharge door should be closed strictly, and the powder shall not be used when measuring.

Attention to asphalt metering system:

(1) before starting production, the piping heating should be sufficient to ensure that the asphalt temperature in the system reaches the specified value;

(2) the asphalt spraying pipe shall be clean and smooth, and the nozzle part shall not be blocked, otherwise the spraying shall not be uniform, and the mixing effect shall be affected.

(3) the bitumen spraying pump or the open valve should be closed and tight, ensuring that no leakage occurs after the asphalt spraying is finished;

(4) the asphalt metering switch valve shall be accurate, timely and well-sealed, and the asphalt measuring barrel suspension shall be firm and flexible.

For the whole system of asphalt mixing station, operators should check frequently. Check whether all the gauges are completely suspended, have a card delay, check whether the work of each weighing sensor is normal and sensitive. Check regularly to match the display value to the actual value. If the problem should be solved in time, ensure that the measurement system is in good working condition.

Secondly, operators should accumulate abundant experience, can foresee most mechanical problems, solve early and eliminate hidden dangers. After the failure, the correct judgment should be made to ensure the normal use of machinery. To be able to do this, the operator will be able to maintain the machinery in a timely manner, as well as the following points:

(1) operators should make frequent visits, observe carefully and carefully check the regular exercise sites. Check whether the joints are loose, whether the lubrication is good, whether the action is flexible, the abnormal wear, etc., the problem is solved timely;

(2) when the stirring is in turn, listen to it with your ears, think with your heart, and understand each sound, if there is an abnormal sound. To find out the cause and properly handle it;

(3) be good at discerning odors. Overrun, such as the oil temperature is too high, discharging temperature, electrical short circuit and burn out, abnormal friction caused by overheat, electric appliances, circuit overload and serious such as heat, send out different smells, through different smells, predictable part of failure.

In a word, the operator should pay attention to look up the color, through various senses, through different instruments, understand every abnormal change, carefully analyze, find out the cause, find out the hidden trouble. Due to the complex structure of the mixing station, the parts are various, which involve the power, gas control system, asphalt supply system, combustion system, measurement system, dust removal system, etc. It is very difficult for an operator to be proficient in all parts in the short term and to accurately judge and eliminate all failures. Therefore, to be a good operator, be careful to observe, think carefully, summarize carefully, and accumulate experience.

In addition to mastering the equipment, the operators should also have the product quality control common sense. It is familiar with the temperature of asphalt mixture, oil and stone ratio and grade match, and can judge the mixture of the mixture, analyze and solve the problem of mixing material in time.

(1) temperature control of mixtures: the temperature of the mixture is one of the criteria for conformity assessment. The temperature is too high or too low to be used. So how to control temperature is one of the basic skills that operators should have. The factors that affect the mixing temperature have the quality of fuel oil. If fuel quality is poorer, low calorific value, burning is not sufficient, can cause heating stone is not stable, low temperature, combustion residue remain in the mixture, after serious impact on the quality of mixture. If the fuel oil viscosity is too big, impurity content is more, moisture content is bigger. It can cause ignition difficulty, blockage of pipes and difficult temperature control. The moisture content of raw materials is another factor affecting temperature. The raw material has a large amount of water and is not uniform. During the production process, the heating temperature of the stone is difficult to control. In addition, the technical conditions of the combustion system, the pressure of the fuel oil supply pump, and the size of the fuel injection are related to the temperature of the mixture. Combustion system of wear, leakage and blockage failure make the parts can't keep the original performance, the system pressure is low, oil is not stable, atomization combustion effect is poorer, seriously affect the mixing temperature. Therefore, experienced operators should be able to accurately determine the quality of the fuel, the degree of moisture in the raw material, and the working conditions of the combustion system. Found the problem in a timely manner to take corresponding measures, although now stirring devices have automatic temperature control, but due to add and subtract from temperature detection flame temperature adjustment needs a process, so the temperature control with hysteresis. To ensure that the mixing temperature, mixing station out waste, operator should through careful observation of the rate of change of temperature, with the result of the change in temperature forecast in advance, and manually add and subtract flame or increase or decrease in feed rate, to control the change of the temperature, the change result does not exceed the scope of the regulations so as to reduce or eliminate waste.

(2) mixture gradation control: mixture gradation of a direct impact on the performance of the pavement, if mixture gradation is unreasonable, the road will be small and large air voids, some diseases, such as floods, rutting, reduce the service life of pavement, the serious influence the quality of the project. Therefore, the grading control of the mixture is one of the skills that the operator must possess. The factors influencing the mixed material grading are: the change of the raw material size, the change of the sieve network of the mixing station, the range of measurement error, etc. The size of the particle size of raw materials directly affects the grading of the mixture. When the raw material changes, the operators should cooperate with the laboratory to fine-tune the production mix. Hot screen station changes is one of the important factors affecting mixture gradation, if mesh plug, inadequate heat material screening, can make the grading and if screen rupture, breakage, leakage, wear overrun, will make the mixture gradation coarse; The measurement error of the mixing station also directly influences the grading. If the measuring error range is too large, it will make the production mix ratio and the target matching ratio deviate greatly, which will seriously affect the quality of the mixture. If the measurement error range is too small, it will increase the metering time and affect the output. It will also make the measurement frequently exceed the limit and affect the normal work of the mixing station. In conclusion, the operator should pay close attention to the changes of the raw material, constantly check the screen, find the problem to be solved in time, and adjust the measurement range to the optimal state according to the characteristics of the mixing station and other factors. Careful consideration of other factors that affect grading, thus ensuring the mix ratio.

(3) the mixture ratio of control: the optimum proportion of asphalt mixture, is the content of mineral aggregate gradation and powder are determined, it is the fundamental guarantee of pavement strength and its using performance, asphalt content is too big, too small can make the road surface produce different diseases.

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

The error range of the bitumen measurement should be adjusted as far as possible. The dosage of the addition of powder is also an important factor affecting the best oil stone ratio, so the metering of powder should be carefully controlled. According to the dust content of the fine aggregate, adjust the opening of the fan wind reasonably, so that the dust content in the mixture is within the design scope.

In the modern construction, it is necessary to have advanced equipment to ensure the quality of the project, but also must have good operation technology, so that the equipment can give full play to its advantages. First-class equipment, first-class operation level, first-class management, only have first-class products, first-class quality. In order to ensure the completion of the project on time and quality.