Two faults in the gas circuit of asphalt mixing plants

In my country, most of the raw materials used in highway construction are asphalt, so asphalt mixing plants have also developed rapidly. However, under the situation of rapid economic development in my country, the problems of asphalt pavement have gradually increased, so the market requirements for asphalt quality have become higher and higher.
There are many factors that affect the quality of asphalt. In addition to the need for asphalt mixing plant equipment to meet conventional requirements, the ratio of raw materials is also very important. At present, my country’s existing industry specifications indicate that the maximum particle size of the asphalt mixture used on the upper layer of the highway cannot exceed half of the thickness, and the maximum particle size of the aggregate of the middle asphalt mixture cannot exceed two-thirds of the thickness of the layer, and the maximum size of the structural layer cannot exceed one-third of the same layer.

Asphalt mixing equipment has a special function, which is that it can perform cyclic heating to make the asphalt product reach the best condition. But how does it achieve this function? Everyone is curious about this.

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.

Asphalt is commonly used in our modern urban life, especially in the process of urban highway construction. As an important road surface paving material, the demand for its use is relatively high. Only by using better relevant material performance characteristics can the overall effect be well helped.
Asphalt mixing plants are equipment products that need to be involved in the production and use of such products. With its own excellent performance, it has been better expanded in the promotion of the existing market use scope. The coordination of external use factors is also a key part, and the relationship between various factors must be handled well.

1: The site should be located on higher ground and away from residential areas and densely populated areas.
Because part of the equipment of the mixing station is installed below the ground, in order to avoid continuous rainfall. The equipment will suffer disaster, and the changing aggregate moisture content will affect the concrete quality. Quality accidents are prone to occur. Therefore, during site construction, attention should be paid to the construction of drainage pipelines and sand and gravel quarries. With the rapid development of cities. With the continuous expansion of urban scale, environmental protection requirements will become more and more stringent. Urban roads prohibit gravel vehicles from passing, so concrete mixing plants should be built far away from urban areas.

We know that the first priority in production is to ensure safety. In the process of operating equipment, staff must always pay attention to using the correct operating methods. Regarding the asphalt mixing plant, it is used to produce asphalt mixtures, modified asphalt mixtures, and colored asphalt mixtures to meet the needs of highways, graded highways, municipal roads, airports, etc.

In the 21st century, with the booming development of modern engineering construction, complex integrated supporting equipment has been invested in large quantities. Its complex process and more independent operating components have relatively high requirements for the performance of its equipment control system. The application of PLC in asphalt mixing station realizes the control of the entire process of asphalt mixing station, which facilitates the construction of modern engineering construction. Therefore, this article discusses and analyzes the application of PLC in asphalt mixing station, which has certain economic value and practical significance.

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.

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 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.

The core of the asphalt mixing plant is its electronic control system. If it has problems, it will cause a lot of trouble to use. However, in actual use, the electronic control system in the asphalt mixing plant will inevitably encounter some problems and failures. How to solve it at this time?
If only the instrument display of the electronic control system of the asphalt mixing plant is inaccurate, it means that the weighing system may be affected by external forces; or the drift error of the sensor causes the weighing zero position or weighing interval to change; it may also be caused by sensor damage.

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.
In order to prevent the asphalt mixer from moving during work, the equipment should be placed in a flat position as much as possible, and at the same time, use square wood to pad the front and rear axles so that the tires are elevated. At the same time, the asphalt mixer must be provided with secondary leakage protection, and it can only be started after the inspection, trial operation and other aspects are qualified.

Colored asphalt pavement is a kind of special pavement material that mixes colored particles into asphalt and then lays on the pavement

Asphalt mixing plants are large-scale products with high professional and technical requirements, and are composed of multiple systems. Among them, asphalt tanks are also a very critical part. Whether it is manufacturing, debugging or installation, it needs to be operated according to the actual application needs of users.
In addition to the manufacturing, debugging and installation, which need to be operated by installers, the maintenance of asphalt tanks in asphalt mixing plants must also be managed by professionals. At the same time, they must strictly follow all safety rules to operate. Before operation, they must be proficient in the relevant requirements and based on the regulations and safety instructions for storing and handling hot asphalt.

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.

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.

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.

The quality of asphalt mixture directly determines the quality of asphalt pavement engineering. This article discusses the key points of supervision of ordinary highway asphalt plants in order to better monitor the quality of asphalt mixture.

The driving device is one of the important components of the asphalt mixing plant, so whether it can operate reliably must be highly valued to avoid adverse effects on the entire asphalt mixing plant. In order to ensure that the driving device in the asphalt mixing plant is indeed complete and reliable, the following maintenance measures are essential.

Natural gas is a colorless, odorless, flammable and explosive gas, the main component of which is methane, which accounts for about 98% of natural gas. The density of natural gas is lower than that of air and it is difficult to liquefy. Natural gas is not only a clean green energy for civil, commercial and industrial use, but also a raw gas for chemical industry. The theoretical ignition value of natural gas is 540 degrees, the combustion temperature is 1970 degrees, the calorific value is 40MJ/m3, and the explosion limit is 5%-15%. CNG refers to natural gas that has been compressed to 20-25MP and stored in high-pressure gas tank trucks, and then transported to various gas transmission points to supply gas to residential users, commercial users and industrial users. In order to ensure the normal operation and safety of the asphalt mixing station and our pressure regulating station, our company has specially formulated the following safety protection measures.

The materials used in asphalt mixtures contain a lot of dust. When the equipment is operating, if the dust enters the atmosphere, it will cause pollution. Therefore, dust removal equipment must be installed, and now bag dust removal is the main method. Safety is a common sense issue. There are well-established standard safety rules.
Do not clean, oil or adjust any mechanical equipment that is not specifically explained during operation; turn off the power and lock it before inspection or repair activities to prepare for accidents. Because each situation has its own particularity. Therefore, be vigilant about safety damage issues, incorrect operation issues and other deficiencies. All of them may lead to accidents, personal injuries, reduced production efficiency, and more importantly, loss of life. Careful and early prevention is the best way to avoid accidents.
Careful and correct maintenance can make the equipment work more efficiently and control it within a certain level of pollution; the maintenance of each component should be carried out according to its operating standards; maintenance plans and safe operation procedures should be formulated according to the inspection and repair conditions that must be carried out.
Take out a work log to record all inspection and repair conditions, list the analysis of each inspection of each component and the description of the repair content or the date of the repair; the second step is to give the inspection cycle for each component, which should be determined according to the service life and wear condition of each component.

The quality of the asphalt mixing plant will be a key factor affecting the quality of the project. After reviewing relevant materials related to the production and construction of asphalt concrete, we summarized some cases of failures in asphalt concrete mixing stations during construction and analyzed the reasons.
1. Unstable output and low production efficiency of asphalt mixing plants
(1) Improper proportioning. The mix ratio of asphalt concrete is divided into target mix ratio and production mix ratio. Among them, the target mix ratio controls the cold material transportation ratio of sand and gravel materials, and the production mix ratio is the mixing ratio of various types of sand and stone materials in the finished asphalt concrete materials specified in the design. The production mix ratio is determined by the laboratory, which directly determines the off-site grading standard of the finished asphalt concrete. The target mix ratio is set to further ensure the production mix ratio, and can be adjusted appropriately during production according to the actual situation. When the target mix ratio or the production mix ratio is not appropriate, the stones stored in each measurement of the asphalt mixing station will be disproportionate, with some overflowing and some other materials, unable to be weighed in time, and the mixing cylinder will be idling, resulting in reduced output.

Any kind of mechanical equipment must go through precise design, testing and other processes before it can be manufactured, and the same is true for asphalt mixing stations. According to the survey, the following stages are necessary for any asphalt mixing plant.
First of all, the main technical parameters of the product to be designed must be determined according to market needs, so construction market research, data analysis and other links are indispensable. Secondly, the ideal working principle and the plan to realize this principle will be determined through innovative conception and optimization screening. , a schematic diagram of the overall design scheme should also be given.

At present, the assembly and installation technology of large-scale asphalt concrete mixing equipment in high-grade highway construction is gradually improving. In order to improve work efficiency, it is necessary to analyze the pretreatment agent for the selection and matching of large-scale mixing equipment and auxiliary equipment, and clarify the installation and commissioning of asphalt stations. With the continuous change of highway construction methods, it is necessary to adopt production equipment according to the requirements of the development of the times. Intermittent asphalt mixing equipment is a widely used road construction equipment with the characteristics of simple operation and high work efficiency. Relevant staff are required to master the installation, construction and management methods of mixing equipment.

There is also a reversing valve in the asphalt mixing plant, which generally does not cause problems, so I have not understood its solutions in detail before. But in actual use, we encountered this kind of failure. How should we deal with it?
The failure of the reversing valve of the asphalt mixing station is not complicated, that is, the reversing is not timely, gas leakage, electromagnetic pilot valve failure, etc. The corresponding causes and solutions are of course different. For the reversing valve to not change direction in time, it is generally caused by poor lubrication, the spring is stuck or damaged, oil dirt or impurities get stuck in the sliding part, etc. For this, it is necessary to check the status of the lubricator and the quality of the lubricating oil. Viscosity, if necessary, the lubricant or other parts can be replaced.
After long-term use, the reversing valve is prone to wear of the valve core sealing ring, damage to the valve stem and valve seat, resulting in gas leakage in the valve. At this time, the sealing ring, valve stem and valve seat should be replaced, or the reversing valve should be replaced directly. In order to reduce the failure rate of asphalt mixers, maintenance must be strengthened on a daily basis.

The application of asphalt mixing plants also involves selection issues. In order to give full play to the performance of the equipment, the model of the machine is mainly determined according to the actual situation of the construction site. It sounds relatively simple, but some details still need to be emphasized.
The so-called specific conditions of the construction site first include the size of the site; secondly, the properties, specifications and working dimensions of the enterprise’s supporting equipment. It is necessary to try to do a good job in all aspects to help improve production efficiency and ensure product quality. In the case of intensive network management, the network management function of the asphalt mixing plant must also be taken into account to avoid difficulties in future upgrades.

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 drying and heating system of the asphalt mixing plant can be regarded as an important part of the whole, so in actual work, it treats the material in a countercurrent heating manner, thereby achieving full dehydration of the cold aggregate, and heating it to a certain temperature, thereby providing the necessary conditions for the normal and continuous operation of the asphalt mixing plant.
During the entire heating process of the asphalt mixing plant, the main purpose is to make the performance of the mixture more in line with the requirements of use, and to make the finished material have good paving performance. Under normal circumstances, the heating temperature of the aggregate is about 160℃-180℃.