Selection issues faced by asphalt mixing plants

The HMA-B series forced asphalt mixing plant can produce reliable quality asphalt in various proportions. The product technology is mature, the operation is stable, the specifications are complete, the efficiency is high, the output is large, and the finished asphalt quality is good. It is suitable for various sizes and This type of road construction project has more obvious advantages in larger-scale road construction projects and high-grade highway construction projects.

Asphalt mixing plant is one of the main equipment for producing asphalt concrete. It can mix asphalt, gravel, cement and other materials together in a certain proportion to obtain the products required for highway construction. In order to ensure its operating effect, the asphalt mixing plant also needs to be powered on for trial operation before it is officially put into work.
The first step in commissioning is to run a single motor and check whether the current, steering, insulation and mechanical transmission parts are operating normally. After confirming that each motor and mechanical transmission parts are operating correctly, conduct a joint trial run. During the entire process, it is necessary to conduct patrol inspections of key parts. If any abnormal noise is found, the cause should be identified and eliminated in a timely manner.

Due to certain restrictions on the current development status and conditions, the profits of the domestic asphalt pavement construction industry are getting lower and lower. Therefore, in the process of using asphalt mixing plants for production, on the one hand, the quality of the products and customer requirements must be ensured. , on the other hand, it is necessary to reduce production costs. Therefore, cost management is very important, and refined management should be implemented in this regard.
First, for device management. Since equipment is the foundation and key of production, in the cost management of asphalt mixing stations, the management of equipment plays an important role in reducing costs. Only by managing the equipment well can the normal working status be ensured, which provides the necessary guarantee for the smooth progress of the project. In fact, in today’s highway projects, equipment costs account for a large part of the cost and profit. The huge profits after the construction of a highway will be greatly affected by the management of materials and equipment.

The drive unit is one of the important components of the asphalt mixing plant, so whether it can be reliably operated must be highly valued to avoid adverse effects on the entire asphalt mixing plant. In order to ensure that the drive unit in the asphalt mixing plant is indeed complete and reliable, the following maintenance measures are essential.
The first thing to pay attention to is the universal rotating part of the drive unit of the asphalt mixing plant. This part has always been a fault-prone part. In order to reduce the occurrence of faults, grease should be added on time, and the wear should be checked frequently, and repaired and replaced in time. Users should also prepare the universal shaft assembly to avoid affecting the working process of the entire asphalt mixer.
Secondly, the cleanliness of the hydraulic oil used in the asphalt mixing plant must be ensured. After all, the working environment of the equipment is relatively harsh, so it is necessary to prevent sewage and mud from entering the hydraulic system. The hydraulic oil should also be replaced regularly according to the requirements of the manual. Once water or mud is found mixed in the hydraulic oil during inspection, the hydraulic system should be stopped immediately to clean the hydraulic system and replace the hydraulic oil.
Since there is a hydraulic system, of course, a matching cooling device is also required, which is also an important focus in the drive system of the asphalt mixing plant. To ensure that its function can be fully exerted, on the one hand, the hydraulic oil radiator should be cleaned regularly to prevent the radiator from being blocked by cement; on the other hand, the radiator electric fan should be checked to see if it is running normally to prevent the hydraulic oil temperature from exceeding the standard.
In general, as long as the hydraulic oil of the asphalt mixing plant drive device is kept clean, there are generally few faults; but the service life varies from manufacturer to manufacturer, so pay attention to its alkalinity observation and replace it in real time.

In recent years, asphalt concrete, as a new green building material, is gradually being valued by people because of its excellent performance in saving resources, being environmentally friendly, ensuring the quality of construction projects, and achieving sustainable utilization of resources. The development of asphalt concrete fully embodies my country’s policies to achieve energy conservation and emission reduction, and is also an important measure to promote the development of circular economy.

Construction safety has always been a major issue, and we cannot let any safety hazard go unnoticed. Especially the use of equipment at the construction site. Asphalt mixing stations are prone to failure. Strengthening the maintenance of this equipment is essential to ensure safe construction at the construction site, improve equipment integrity, reduce equipment failures, and ensure the quality of concrete. The role of neglect.
The composition of the asphalt mixing plant is relatively complex, so during maintenance, classified maintenance should be carried out according to the usage and functions of different parts. Maintenance content can be divided into tank maintenance, winch system maintenance and adjustment, stroke limiter adjustment and maintenance, wire rope and pulley maintenance, lifting hopper maintenance, track and track bracket maintenance, etc.

Modified Bitumen

Judging from the situation of highways in our country, asphalt pavement is the most used, which is one of the reasons why asphalt mixing plants have developed so rapidly. Under the situation of rapid economic development, the quality problems of asphalt pavement are gradually increasing, which puts forward higher and higher requirements for the quality of asphalt. It is understood that the primary factor that affects the quality of asphalt is the ratio of raw materials. This is also covered in the introduction of asphalt mixing stations. You can discuss it together.
In order to obtain high-quality asphalt products, in addition to the asphalt mixing equipment meeting the requirements, selecting the appropriate asphalt mixture gradation type is also a top priority. According to my country’s current regulations, the maximum particle size of the asphalt mixture in the upper layer of the highway should not exceed half of the layer thickness; while the maximum particle size of the aggregate in the middle surface layer of asphalt mixture should not exceed two-thirds of the layer thickness; and the asphalt layer should not exceed half of the layer thickness. The maximum nominal aggregate size of the pavement structural layer mixture should not exceed one-third of the layer thickness.
Based on this analysis, if an asphalt surface layer with a certain thickness is selected according to the above specifications, the particle size of the asphalt mixture aggregates will generally be larger, which will inevitably bring insurmountable construction difficulties to the construction of asphalt concrete pavement. After investigation, testing, analysis, and comparison, it can be seen that the lower layer has a wider choice, so the AG-201 gradation type can be used; while the selection of the upper layer mixture type is more difficult, and it is necessary to achieve a reasonable choice of this mix ratio. , on the one hand, we must examine as many aggregate resources as possible, and on the other hand, we must also consider the model of the mixing equipment.
In order to ensure the quality of the project, strict selection and inspection of engineering materials must be carried out. Therefore, the selection and determination of raw materials should be based on the requirements for pavement structure and use quality, combined with the supply of floor materials, and inspection in accordance with the requirements of relevant test procedures, and then Select the best materials so that all technical indicators of the materials meet the specified technical requirements.

As a special equipment, standardizing the operating procedures of important production tools of asphalt mixing stations, conducting daily maintenance, regular inspections, eliminating hidden dangers, etc. can effectively ensure the safety and stability of the equipment and prevent equipment from malfunctioning due to misoperation. causing equipment damage. Good maintenance operations can also greatly extend the service life of asphalt mixing plants. Therefore, before daily operation, the asphalt mixing plant must be properly maintained to make the asphalt mixing plant operate better and create wealth.

With the strengthening of the trend of environmental protection and energy conservation, the environmental protection of asphalt mixing plants has gradually become the mainstream form of mixing plant development. What kind of equipment can be called an environmentally friendly asphalt mixing plant? What are the basic conditions that must be met?
First of all, as an environmentally friendly asphalt mixing plant, it must meet the requirement of using less energy consumption during use. That is to say, under the conditions of the same quantity and quality, less energy is consumed during the operation process, including various resources such as water and electricity.
Secondly, environmentally friendly asphalt mixing plants not only require less energy consumption, but also must achieve higher production efficiency, while also reducing carbon emissions in the entire production process, so as to meet the proposed low-carbon production requirements

The mobile forced asphalt mixing equipment adopts intermittent drying cylinder, double forced mixer, the main machine can be towed, small footprint, short installation cycle, convenient operation and maintenance, good stability, high degree of automation, high degree of standardization, and high quality of finished products, and the technology of continuous improvement. The mobile forced asphalt mixing plant is suitable for high-grade road asphalt paving and maintenance.
1. The combined structure of the drum dryer and the batching machine is installed on a movable bracket for easy movement.
2. The asphalt mixing plant is equipped with a double horizontal shaft to boil the aggregate and ensure uniform mixing.
3. In the densely arranged hanging barrels, the hot aggregate rises vertically. This lifting tool is easy to use and reliable.
4. For accurate weighing of aggregates, asphalt and powder ore, a measuring scale is used, which contains a weighing sensor for electronic measurement.
5. The movement of the power material follows a closed spiral path, which ensures little material loss and provides safe transfer.
6. On the cyclone burner, high-pressure oil is sprayed out and quickly atomized. In the combustion chamber, the material is fed in a spiral manner and automatically ignited by the oil mist, which ensures combustion efficiency. The cylindrical barrel of the burner is separated from the burner head. The furnace cavity can be pushed in and pulled out, which is convenient for replacing the damaged side column bricks inside the burner. The entire burner has a large heat capacity and high thermal strength. This is cost-effectiveness.

Determining the material is a necessary stage in the design process of asphalt mixing equipment, and it is also one of the most critical links, because the material will be directly related to the use effect and service life of the entire equipment. Generally, when we determine the machine material, we usually base it on the characteristics of the working medium, and the same is certainly true for asphalt mixing equipment.

Safety is the key point for any piece of equipment, and asphalt mixers are of course no exception. What I want to share with you is the knowledge in this area, that is, the safe operation specifications of asphalt mixers. You might as well pay attention to it.

Due to its complexity and importance, asphalt mixing plants are more critical in road construction. Modern asphalt mixing stations have five key systems. Do you know what they are?
1. Mixing system of asphalt mixing plant
Mixing equipment is one of the key systems, why? Usually, the productivity of the mixing equipment has a great impact on the next step of construction efficiency. Most asphalt mixing plants use twin-shaft forced mixing. Since the drying drum and burner of the mixing equipment have strong overload capabilities, and in most cases, the moisture content of the mineral materials is less than 5%, this improves the productivity of the mixing equipment. provide conditions. The mixing blades of the mixer have an adjustable assembly angle and are driven by dual mixing shafts and dual motors.

Asphalt mixing plant, also known as asphalt concrete mixing plant, asphalt mixing equipment. Refers to a complete set of equipment used for mass production of asphalt concrete. According to the mixing method, it can be divided into intermittent type and continuous type; according to the transportation method, it can be divided into fixed type, semi-fixed type and mobile type.

As an important production equipment in construction, asphalt mixing plant has high production investment. Therefore, production is very important during use, but daily maintenance is also very important. In addition to regular maintenance, routine maintenance is also essential. The editor of Asphalt Mixing Plant shares some key points of daily maintenance and scheduled maintenance;

What should I do when the reversing valve in the asphalt mixing plant fails? The editor has a trick:
1. The reversing valve cannot be reversed or the reversing action is slow, which is generally caused by poor lubrication, stuck or damaged springs, oil or impurities stuck in the sliding parts. In this regard, you should first check whether the oil mist is working normally; whether the viscosity of the lubricating oil is appropriate. If necessary, the lubricating oil should be replaced, the sliding part of the reversing valve should be cleaned, or the spring and reversing valve should be replaced.

[1]. Composition of intermittent asphalt mixing plant
The intermittent asphalt mixing plant mainly consists of cold material silo, cold material distribution system, cold material conveying system, combustion and drying system, ventilation and dust removal system, hot material elevator, vibrating screen, hot material silo, powder conveying system and asphalt conveying system. System, metering system, mixing cylinder, control system, finished material transportation and storage system, asphalt heating and insulation system, etc.
2. Discussing the phenomenon of warehouse cascading in asphalt concrete mixing plants
2.1 First, let’s introduce the structure and principle of vibrating screen. The main components include: RetentionRubber, SupportTube, vibrating screen drive system and supporting electrical components
The working principle is introduced as follows: hot aggregate is sent to the vibrating screen through the hot aggregate elevator, and the hot aggregate is vibrated and screened by the vibrating screen. Stones of different specifications enter their corresponding hot aggregate bins through the screen and cannot pass through the geotechnical work. The super-sized particles from the cloth screen enter the overflow bin and are sent out.

Asphalt concrete mixing equipment generally uses conveyor belt conveyors to transport cold materials. Its main advantages are large conveying capacity, continuous operation, simple equipment structure and automatic control. However, belt deviation is a common fault, which directly affects the drying operation of the drying drum and also affects the production efficiency of the mixing equipment. Therefore, it is very important for the asphalt mixing station to solve the belt deviation problem at the operation site of the asphalt concrete mixing equipment.

The mixing speed of asphalt mixing plant equipment is indeed very fast, and the corresponding mixing power must be very high, but the specific amount must be measured in a certain way to determine the scope of use of asphalt mixing equipment. There are many methods to measure the mixing power of asphalt mixing equipment, but the relatively small errors are the motor counter-torque measurement method and the strain measurement method.
When the motor of the asphalt mixing equipment starts running, the electromagnetic moment acting on the motor rotor and the electromagnetic moment acting on the motor stator are equal, but their directions are opposite. Therefore, as long as the torque acting on the stator is measured, the torque on the rotor can be obtained, and the actual mixing torque is obtained after deducting the friction torque on the rotor bearing.
On the premise of knowing the torque and mixing speed, the mixing power of the asphalt mixing equipment can be calculated. This is the so-called motor counter-torque measurement method, which is relatively simple and suitable for smaller mixing systems.

Asphalt damage avoidance mechanism in asphalt mixing plant
1. Asphalt operators should undergo physical examination. Anyone suffering from conjunctivitis, skin disease or allergic reaction to asphalt should not engage in asphalt work.
2. Asphalt operators must apply protective ointment on exposed parts of their skin, and a first aid kit should be provided on the construction site.
3. The factory uniforms and protective equipment of asphalt operators are stored in a centralized manner and are prohibited from being worn home or entering collective dormitories.
4. The transfer of lumpy asphalt should usually be carried out at night and on cloudy days, especially during hot seasons. Small machinery should be used for loading and unloading, and it should not be lifted and transported directly by hand.

Certain failures cannot be avoided during the use of the asphalt mixing plant. For example, a malfunction of the cold material feeding device may cause the asphalt mixing plant to shut down. This may be due to a malfunction in the asphalt mixing plant or due to gravel or foreign matter being trapped under the cold material belt.

The first step in establishing an asphalt mixing station is to determine the host machine and feed batching system. Generally, the configuration is based on the project’s construction period, total amount of concrete, daily concrete consumption and other indicators. The basic principle is to meet the daily concrete consumption. Under normal circumstances, a project can only have one asphalt mixing station, or separate mixing stations can be set up according to zones, or a large mixing station can be set up together with an appropriate number of concrete transport trucks, all of which depend on the actual situation.

Asphalt mixing plants are highly professional equipment with complex systems. It is inevitable that some failures will occur during use. So, what are the common hardware failures of asphalt mixing plants? Do you know?
(I) Because its system is relatively complex, when different components have problems, the problems caused may be different. If during the operation, it is found that the material addition of each silo is inaccurate, this problem may be due to the failure of the sensor of the asphalt mixing plant. At this time, the machine should be stopped for inspection and replaced with a new sensor if necessary. It may also be caused by the jamming of the scale bar. At this time, foreign objects should be removed in time.

There is also a reversing valve in the asphalt mixer, which generally does not cause problems, so I have not understood its solution in detail before. But in actual use, we encountered this kind of failure. How should we deal with it?

In today’s road construction, the use of a large number of road construction machinery represents the entry into the era of highway mechanization. For users, the goal is to use road construction machinery reasonably and tap its potential as much as possible. However, road construction machinery requires various accessories to work together. Now let’s take the asphalt mixing plant as an example to see what commonly used accessories and equipment are available.
Asphalt mixing plant equipment is a relatively complex system, which includes many equipment, mainly nine parts, namely: bag dust removal, finished material temporary storage warehouse, grading machine, fast heating asphalt tank, asphalt barrel removal machine, asphalt recycled material crushing and screening system, coal block crusher, coal mill and dust removal equipment, etc.

When we operate the asphalt mixing station, we should heat the equipment half an hour in advance, and the clear tank should be heated for at least two hours; and manually operate each part of the equipment to ensure that it is in good operation. status; it is also necessary to conduct relevant inspections on the valves and manually collect and return oil to ensure that the equipment can operate normally.
Several requirements for safe operation of asphalt mixing plants:

Judging from the current situation of domestic highway construction, asphalt mixing stations will also achieve great development for a long time to come. This is also a result of rapid economic development. However, we have found that more and more quality problems occur when constructing asphalt pavements in modern times. Therefore, we have to put forward more stringent requirements for the quality of asphalt.

Asphalt flue gas treatment methods, their principles and characteristics, and an asphalt flue gas environmental protection treatment plan based on the actual asphalt flue gas problems faced by the unit.

1. Basic situation
My unit’s mixing plant is equipped with a 4000-type asphalt mixing plant. During daily production of the asphalt mixing plant, a large amount of asphalt smoke will be emitted from the mixing pot discharge port. This smoke not only has an unpleasant smell, but also contains A large number of compounds that are harmful to the human body, such as benzopyrene, benzanthracene, carbazole and other polycyclic aromatic hydrocarbons, mostly have carcinogenic risks. Smoke overflow will cause pollution to the surrounding atmospheric environment and affect the personal health of workers. Although the overflow port of the mixing station is equipped with a dust retaining wall, the fine dust is seriously raised, and the cold material belt conveyor is dusty. In order to protect the environment, reduce pollution, and reduce cost investment, based on full research and absorption of technology in the same industry, and combined with the actual situation of asphalt mixing, we are planning to install asphalt mixing bag dust collectors to the flue at the discharge port of the mixing pot to control asphalt fumes. Gas is processed. The dust removal efficiency of the bag dust collector can reach 97%~99%, and the dust-containing gas can be purified to a level of 50mg/Nm3.

During the operation of the asphalt mixing plant, the quality of the mixture is often related to its construction quality. Therefore, we need to improve the quality level of the mixture as much as possible, and the temperature of the mixture is one of the standards for the qualification assessment of the mixture. In other words, if the temperature is too high or too low, the mixture may become waste and cannot meet the needs of use.
Therefore, reasonable control of the temperature of the mixture is one of the basic conditions that must be met for the normal production of the asphalt mixing plant. Among them, the quality of the fuel will affect the temperature of the mixture. For example, if the quality of the fuel is poor, the calorific value is low, and the combustion is incomplete, it will lead to unstable heating, low temperature, and a large amount of residue will be produced after combustion, affecting the quality of the mixture. If the viscosity is large, it will also cause ignition difficulties and the temperature is not easy to control.