How should the drying and heating system of the asphalt mixing plant be set up?

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:

The renovation of the combustion-supporting system of the asphalt mixing plant and the use of DC frequency conversion CNC machining technology are all renovations of the original system. In addition to the above renovation plans, with the existing equipment and personnel, what other measures can be taken in the application to reduce the operating costs of concrete mixing plants?
At present, China has no mandatory national industry standards for heavy residual oil, and the quality of fuel oil varies greatly. Even from the same dealer, the quality difference between batches is very large, and it contains more residues. Therefore, bridge inspection equipment should be installed on the construction site, and professional personnel should inspect various performance parameters of gasoline and diesel to strictly control quality.
When the burner is working, if the flame of the combustion aid is red and the smoke from the ash removal chimney is black, this is the manifestation of poor atomization of gasoline and diesel and insufficient combustion aid. At this time, the following measures should be taken to deal with it: properly adjust the distance between the nozzle and the vortex plate, generally push it inward to a suitable distance, the purpose is to prevent the atomized oil cone sprayed from the nozzle from spraying into the vortex plate; effectively adjust the ratio of gasoline and diesel to gas, so that the gasoline and diesel increase the mass conversion law slowly, or the gas increase the mass conversion law quickly; promptly remove the carbon deposits and coke around the nozzle to prevent the flame from deflecting; heavy residual oil contains more residues, which can easily cause serious damage to the high-pressure oil pump and increase the working pressure, affecting the actual effect of atomization and the shape of the flame, so the high-pressure oil pump must be repaired or replaced in time; install metal filter devices in front of the first and second high-pressure oil pumps, and clean them frequently to prevent the residues in the gasoline and diesel from blocking the nozzle.
The operators should be trained in professional skills on a regular basis to strengthen their job responsibilities and moral education, so that they can establish their respective job responsibilities, understand the importance of their positions, understand the content of their work, and improve their professional level. Skilled operators can properly control the temperature of the asphalt mixing plant mixture to avoid gasoline and diesel waste.
In order to improve the combustion-supporting effect and effectively reduce the operating costs of asphalt mixing stations, Sinoroader Group kindly reminds that the following issues should be noted when using the burner in the asphalt mixing station: To improve the maintenance of the burner, the burner nozzle should be cleaned of charred materials and carbon deposits on the ignition electrode regularly. The nozzle can be disassembled according to the atomization status; the air-oil ratio of the burner is generally not adjusted, and the fuel pump pressure can be adjusted according to the smoke status and the temperature of the asphalt mixture; the sulfur dioxide generated by the combustion of light fuel oil has a strong corrosion to the bag, so the bag should be maintained regularly and the air pressure changes in the bag should be paid close attention to; water deashing will produce more foam, causing the sand settling tank to flow out, so the sand settling tank should be cleaned in time, and a watering design should be carried out to settle the foam; when the steam pressure decreases or the gear oil pump noise increases, the gear oil pump must be replaced.
When the burner is started, the fuel oil circulation system should be completed through the valve, and then the burner control box should be opened to start the burner. If the electronic ignition of the fuel oil fails, you can change the inlet tee and use the diesel engine for ignition. After the ignition is successful for 2 minutes, you can convert it into fuel oil. In this way, even the light fuel oil of lower quality can ensure combustion.

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;

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. 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.

The asphalt mixing plant is a complete set of equipment for mass production of asphalt concrete. The whole machine of the equipment consists of multiple systems, such as batching system, drying system, combustion system, powder supply system and dust prevention system. Each system is an important part of the asphalt mixing plant.
The working condition of the combustion system of the asphalt mixing plant has a great impact on the whole system, which is related to the economic efficiency of the whole system, temperature control accuracy and flue gas emission indicators. This article will briefly introduce how to judge the working condition of the combustion system of the asphalt mixing plant.
Generally speaking, due to the complexity of the detection equipment and methods, there are no conditions to achieve in the working process of most asphalt mixing plants. Therefore, it is more convenient to judge the working condition by a series of relatively intuitive factors such as the color, brightness and shape of the flame. This method is very simple and effective.
When the combustion system of the asphalt mixing plant is working, when the fuel is burning normally in the drying cylinder, the user can observe the flame through the front of the cylinder. At this time, the center of the flame should be in the center of the drying cylinder, and the flame is evenly distributed around it and will not touch the cylinder wall. The flame is full. The whole outline of the flame is relatively clear, and there will be no black smoke tail.
The abnormal working state of the combustion system includes, for example, the diameter of the flame is too large, which will cause serious carbon deposits on the furnace tube and affect the subsequent working state of the combustion system.

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.

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.

1. Causes of overflow
The main causes of spillage are:
1) Mixing materials in cold silo. Cold material warehouses generally have 5 or 4 warehouses. Each warehouse is required to contain pellets of a certain specification. If cold materials of different specifications are mixed or mistakenly loaded during the loading process, it will cause certain occurrences in a certain period of time. The shortage of pellets of one specification and the overflow of pellets of another specification can easily destroy the supply balance between hot and cold silos.

In fact, don’t be misled by the name. The asphalt mixing plant we are talking about here does not necessarily refer to simple asphalt mixing, but may also refer to asphalt concrete mixing, so it is actually a mixing plant. At present, asphalt mixing plants generally use complete sets of equipment for mixing purposes. The benefits of using complete sets of equipment are as follows.
1. Higher efficiency
For the current industrial production, complete sets of equipment can help improve production efficiency and ensure production quality. This is why even in mixing plants, the equipment used is mainly complete sets of equipment.
2. Ensure quality
When mixing asphalt, a certain ratio will be set. For this type of asphalt liquid used in different occasions, its ratio control has strict requirements. Only by ensuring its mixing method and mixing time can the asphalt liquid be ensured to be used in the production site. One of the benefits of a mixing station is that the quality can be effectively controlled.
3. Ability to perform random inspections
After mixing at the mixing station, relevant quality inspection personnel can conduct random inspections to ensure that the mixed asphalt liquid meets the use requirements.
In short, asphalt mixing plants use complete sets of equipment, mainly to facilitate the asphalt to meet production needs in the later stage. Using a mixing plant, it can better control the mixing time and the order of feeding, so as to ensure that the mixed products meet different usage requirements. And after using the archived equipment, effective sampling can also be carried out, which can better ensure that the quality meets the construction.

Asphalt mixing plants bring a lot of convenience. You should understand what asphalt is. Asphalt is a very viscous liquid with a black surface that dissolves carbon disulfide. They generally exist as asphalt and smoke tar. Asphalt appeared early in social life.

Synchronous gravel sealing in road maintenance can quickly improve road driving performance, repair anti-skid performance, smoothness, etc. It is used in preventive maintenance and is also one of the methods of low-grade road pavement construction. Synchronous gravel seal has the advantages of high strength, rough surface, non-slip, impermeable, good durability, and prevention of water mist when driving on rainy days. The so-called synchronous gravel sealing layer is to use special equipment, namely the synchronous gravel sealing truck and the bonding material (modified asphalt or modified emulsified asphalt) to be spread simultaneously on the road surface, and the single layer of asphalt wear is formed by natural driving or rolling with a road roller. layer, mainly used as asphalt surface layer.

Asphalt mixing stations play an important role in road construction. This article starts from the site selection, commissioning, and acceptance of the asphalt mixing plant, and elaborates on comprehensive and reasonable planning to avoid disturbing the normal construction order.

Asphalt mixing plant, also known as asphalt concrete mixing plant, is a complete set of equipment for batch production of asphalt concrete. Its efficient and stable operation is of great significance to ensure the quality of the project. It is mainly used in the construction of highways, grade roads, municipal roads, airports, ports and other projects. According to the mixing method, asphalt mixing plant can be divided into forced intermittent type and continuous production type; according to the transportation method, it can be divided into fixed type, semi-fixed type and mobile type.
The working principle of asphalt mixing plant mainly includes steps such as aggregate processing, asphalt processing and mixture mixing. Specifically, aggregates (such as gravel, crushed stone, etc.) are sent to aggregate bins through conveyors or bucket elevators, and then measured by aggregate metering devices, and a certain amount of aggregates are sent to sub-bins. Asphalt is stored in asphalt bins or oil storage tanks, and is measured by asphalt metering devices, and a certain amount of asphalt is sent to asphalt sub-bins. Finally, according to the ratio requirements, different aggregates are taken out from their respective sub-bins and sent to the mixture mixer through conveyors or bucket elevators for mixing.

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.

[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.

Emulsion bitumen equipment has stable product quality, closed material transmission, high degree of automation and civilized production, and is easy to standardize management. The double-mill configuration can be used to produce modified emulsified asphalt.
At present, emulsified asphalt equipment is widely used in new technologies and processes for preventive maintenance, such as fog seal, slurry seal, micro-surfacing, cold regeneration, crushed stone seal, cold mix and cold patch materials.
Emulsion bitumen equipment is an emulsion at room temperature formed by dispersing asphalt into the water phase. It is a new material for the use of elements. Compared with traditional hot asphalt, it saves more than 50% of energy and 10%-20% of asphalt, and has little pollution. The biggest feature of emulsified asphalt is that it can be stored at room temperature. It does not need to be heated during spraying and mixing, nor does it need to heat the stone. Therefore, it greatly simplifies the construction, avoids burns and scalds caused by hot asphalt, and avoids the fumigation of asphalt steam when paving high-temperature mixtures. It is very popular among road maintenance workers.

In fact, asphalt mixing stations are not uncommon in our daily lives. They are mainly a unit of equipment specially designed to mix asphalt. What we really don’t understand is the gas system of the asphalt mixing station. Only correct maintenance And operation can bring out the best production effect. So what are the faults in the gas circuit of asphalt mixing station?
The following three points are the more common gas path failures of asphalt mixing stations:

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℃.

Bitumen is a polymer mixture composed of asphaltene, colloid, aromatic hydrocarbons and saturated hydrocarbons. Asphaltene is dispersed in aromatic hydrocarbons and saturated hydrocarbons with the help of colloid to form a colloidal structure. When the asphaltene content is low, the bitumen has good adhesion, plasticity and fluidity, but poor temperature stability and elasticity
Bitumen modification principle:
Bitumen is a polymer mixture composed of asphaltene, colloid, aromatic hydrocarbons and saturated hydrocarbons. Asphaltene is dispersed in aromatic hydrocarbons and saturated hydrocarbons with the help of colloid to form a colloidal structure. When the asphaltene content is low, the bitumen has good adhesion, plasticity and fluidity, but poor temperature stability and elasticity. The polymer modifier is similar to the asphaltene in bitumen. Its addition, after fully swelling with bitumen, absorbs the aromatic hydrocarbons and colloid in bitumen to form a new colloid, which not only retains or increases the adhesion, plasticity and fluidity of the original bitumen, but also improves the temperature stability and elasticity of bitumen, thereby achieving the purpose of improving the road performance of bitumen.
Bitumen modification process:
The modifier and additive are evenly and finely dispersed into the matrix bitumen, and the contact area between the original bitumen and the modifier is increased as much as possible to ensure full swelling and development, which not only improves the utilization rate of the modifier but also makes the original bitumen performance the most perfect improvement.
The modified bitumen complete production equipment has the following advantages:
1. It is suitable for a variety of modifiers, such as SBS, EVA, PE, etc.;
2. The ratio of modifier to bitumen can be set at any time according to user needs;
3. The production volume of each cycle can be set arbitrarily within the maximum productivity;
4. The modified bitumen has high quality, and the modifier has a small particle size and uniform distribution after emulsification;
5. The production process is fully automatically controlled, and the production records can be queried at any time;
6. The weighing system is accurate in measurement, and the weighing error is less than 1%;

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.

When an ordinary asphalt mixing station completes the mixing operation, it will cause great pollution to the surrounding environment. In order to solve this problem, environmentally friendly asphalt mixing equipment came into being. What are the characteristics of this type of equipment?

For road construction machinery, the following is mainly about the asphalt mixer in road construction machinery equipment. Because it is the key product of Wuxi road construction machinery manufacturers, it is necessary to carry out comprehensive training and mastery, so as to ensure meticulousness and practicality, and not ignore any knowledge points.
1. In road construction machinery, is there any difference between asphalt mixing equipment and asphalt concrete mixing equipment?
The answer given by Sinoroader Group manufacturer to this question is no, that is, there is no difference between asphalt mixing equipment and asphalt concrete mixing equipment. They refer to the same type of equipment, but they are different in name. It can be said that they are two names for the same type of equipment, and there is no difference in essence.
2. During the operation of the asphalt mixer, there is a sound in the mixing pot. What’s the matter?
In the view of Sinoroader Group, there are two answers to this question. One is that the mixer arm on the asphalt mixer is not good or damaged. The second is that the wear-resistant lining in the mixer is damaged, which leads to this problem.
3. What are the dust removal devices in the asphalt mixing equipment?
In the asphalt mixing equipment, for its dust removal device, Sinoroader Group believes that the key is to use the dry ash removal method, because it can facilitate the collection of raw materials. In terms of its dust removal equipment type, there are filter dust removal equipment, centrifugal fan dust removal equipment and force dust removal equipment, etc., which can all be used well.
For the asphalt mixer and asphalt mixing equipment in road construction machinery, I believe that through the practical discussion of the above relevant content, everyone can master it well and master it, so that in practice, they can have new gains and benefit a lot from it.

The asphalt mixing equipment mentioned here may also refer to an asphalt concrete mixing plant. At present, asphalt mixing equipment generally uses a complete set of equipment for mixing. So what are the benefits of using a complete set of equipment?
1. More effective.
In today’s industrial production, a complete set of asphalt mixing equipment can help improve production efficiency and ensure product quality. This is why even in a mixing plant, the equipment used is a complete set of equipment.
2. Ensure quality.
When mixing asphalt, a certain ratio is set. For this type of asphalt liquid used in different occasions, its ratio control has strict requirements. It is necessary to determine its mixing method and mixing time to ensure that the asphalt liquid is consistent with the production site. One of the advantages of a mixing plant is that the quality can be effectively controlled.
3. It can be sampled.
After mixing at the mixing plant, the quality inspector can sample and inspect to ensure that the mixed asphalt liquid meets the use requirements.
In short, asphalt mixing equipment will use a complete set of equipment, mainly to facilitate the later asphalt to meet production needs. Through the mixing plant, the mixing time and feeding sequence can be better controlled, so that the mixed product can meet different use requirements. And after using the archiving equipment, effective spot checks can be carried out, which can better ensure that the quality meets the construction requirements.

In recent years, asphalt pavement has dominated highway surfaces. With the rapid development of our country’s national economy, highway traffic volume is increasing, axle loads are increasing rapidly, vehicle speeds are increasing, and there are more and more quality problems occurring on asphalt pavements. Some are damaged after repair, and some have a service life of up to Less than design age. This has put forward increasingly higher requirements for the quality of asphalt pavement, and an important factor affecting the performance of asphalt surface layers is the gradation composition of the mixture. This article discusses the mix design of asphalt mixture.

Asphalt concrete, as the name implies, is a composite material formed by combining asphalt and concrete. Its main components usually include three categories, aggregate, filler and asphalt. Aggregate, as the basic skeleton of asphalt concrete, is mainly composed of crushed stones of different sizes. These crushed stones are carefully selected and proportioned to ensure the strength and stability of asphalt concrete. Filler usually refers to fine-grained materials such as stone powder, which are filled between crushed stones to increase density and improve overall strength. Asphalt is a binder that can tightly bond aggregate and filler together to form a solid whole. In the process of producing asphalt concrete, the proportion of various raw materials will be adjusted according to different formulas. These formulas are usually formulated according to the specific requirements of the road and the use environment to ensure that asphalt concrete can meet various complex road conditions. The place where this composite material is produced is a special asphalt mixing plant. This is an asphalt concrete mixing plant. The large trucks that we see every day to transport asphalt concrete come out from here. In the asphalt mixing plant, the entire production process is finely divided into multiple steps.
First, workers use loaders to deliver aggregates into cold silos. Cold silos are usually divided into several different chambers according to the size of aggregate particles, and each chamber corresponds to aggregates of different specifications. In this way, in the subsequent mixing process, the proportion of various aggregates can be accurately adjusted according to customer needs.
Next, these aggregates will be sent to the drying drum through a vibrating feeder and a belt conveyor. In the drying drum, the aggregates will be heated to a specified temperature by the high-temperature heat source provided by the burner. During this process, the spiral blades and sheep feed plates inside the drum will ensure that the aggregates are fully heated during rotation and remove the moisture in them. In this way, not only can the bonding strength between aggregates and asphalt be improved, but also the stability and durability of asphalt concrete after paving can be ensured.

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.

Asphalt mixing plant is a very practical engineering machinery. Especially in the road construction process, it plays an irreplaceable role. Due to its importance, in addition to ensuring its own quality, the use and maintenance of the equipment must be carried out normally. Let’s learn about the daily maintenance requirements of asphalt mixing plants.

At present, most asphalt mixing plants have different degrees of energy loss in use, and these losses have brought us serious waste. How to reduce energy consumption in these aspects and achieve efficient production?
First of all, we must first summarize which aspects have energy loss, and then we can find reasonable solutions based on these problems. Through research, it is found that there are four problems in the use of asphalt mixing plants and the production of asphalt mixtures. The content and measures are as follows:
The first aspect is the management of the pile. We can reduce the energy consumption of the asphalt mixing plant through 3 specific methods: 1. Appropriately reduce the stacking height of the pile; 2. Build an inclined pile site with a good drainage structure; 3. Build a waterproof canopy.

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.