Characteristics of LB3000 Bitumen Hot Mix Plant

High quality

·Accurate temperature control, screening, metering and uniform mixing ensure that the equipment can stably provide high-quality asphalt concrete.

High efficiency

·High productivity: fast and stable belt transmission, high-energy and low-consumption drying heating drum, precise and efficient vibrating screening, large-capacity dual-shaft forced mixer.

·Environmental protection: Optimized combination of two-stage dust removal system, stable and efficient pulse back blowing bag filter, advanced and thorough waste powder humidification treatment system.

·Energy saving: low-pressure atomization burner, electric proportional adjustment, full combustion; drying drum, optimized layout design of blades; optimal matching between the two and the dust removal system, higher thermal efficiency.

High reliability

·Advanced and reliable design, meticulous manufacturing, more than 20 years of trials and hardships, and industrial appraisal under a variety of harsh working conditions have created the high reliability and excellent quality of Daynn asphalt mixing plant.

Characteristics of LB3000 Bitumen Hot Mix Plant

LB3000 batch asphalt mixing plant is a new generation product developed by our company by absorbing foreign advanced technology and integrating the advantages of various domestic models. The plant adopts advanced three-dimensional design and efficient production and processing technology to ensure the unity of technology and quality. It adopts modular design, compact structure, fast transportation and installation, simple operation, high degree of automation, advanced configuration, reliable performance, low noise, no pollution, and dust emission standards. This product is suitable for pavement construction on high-grade highways, airport roads and other places.

Features:

1. Control system: It adopts the latest generation of human-machine interface control, and can be configured with a video industrial monitoring system to monitor the operating status of the equipment in real time. The components are selected from internationally renowned control components to provide reliable quality assurance. The plant is simple to operate, stable and reliable, and technologically advanced. Full computer Chinese dynamic process interface, full-screen display, real-time monitoring and alarm; operation starts according to the process, highly automated. The management system can integrate the resource advantages of the mixing plant, optimize and control each link of the production process, increase productivity, and reduce the consumption of energy (electricity, fuel) and other raw materials.

2. Mixing system: adopting European twin-shaft paddle mixing technology to realize large-circulation and three-dimensional mixing, so that the mixture can be uniformly stirred in a short time; wear-resistant blades and liners are made of chromium-molybdenum alloy wear-resistant cast iron; high-speed synchronization is adopted Organization, effectively reducing equipment maintenance links.

3. Weighing system: Asphalt weighing adopts coarse weighing and precise weighing technology, which has higher weighing accuracy; advanced full-computer automatic drop compensation function to ensure more accurate control of the metering system.

4. Combustion drying system: multiple options such as fuel oil, gas, fuel, etc. The drying drum is driven by an internationally well-known reducer, and it runs easily and freely; the material extraction blades are optimized for design, and the heat utilization rate is high; the outside of the drum is provided with an insulation layer to reduce heat loss; the drum discharge port is equipped with a temperature measurement device.

5. Cold aggregate supply system: The aggregate feeder adopts 3+3 module combination form. Six-stage equipped with speed reducer frequency conversion speed regulation; the entrance of the bin is equipped with a screen and the size of the material door is adjustable. Two sand bins are equipped with silo wall vibrators to prevent material blocking.

6. Vibrating creen system: The international advanced five-layer vibrating screen is driven by dual motors and the excitation force is automatically coupled; the vibrating screen has a bypass bin structure that is more convenient to use, and has the ability to efficiently and reliably respond to different types of ingredients.

7. Dust removal system: adopts two-stage dust removal design with one-stage gravity dust removal and two-stage bag filter; selected waterproof and oil-repellent Nomex knitted felt; adopts automatic wind pressure adjustment control system to ensure dust removal quality and environmental protection standards; There is an insulation layer on the outside of the bag filter to avoid condensation on the bag and reduce operating and maintenance costs.

The detailed structure of Bitumen Hot Mix Plant

The basic structure of the mechanical system of asphalt mixing plant

Asphalt mixing plant connects the relatively independent units to form a system centered on the mixing body. These units mainly include: cold bin unit, drying drum, burner, hot aggregate elevator, vibrating screen, metering system, mixer, finished product silo, asphalt heating system, dust removal system, filler system, control system, Pneumatic system, etc., as shown in the figure.

1- cold aggregate supply system; 2- drying drum; 3- dust removal system; 4- filler supply system;

5- hot aggregate elevator;6-Vibrating screen; 7-Hot aggregate bin;

8-Measuring and mixing system; 9-Finished product bin

 

Pre cold aggregate supply system

The pre cold aggregate supply system is the beginning of the production process of the asphalt concrete mixing plant. The aggregate is first proportioned according to the grading requirements of the asphalt mixture. It is mainly composed of several independent cold storage bins, feeding belt conveyors, a collection belt conveyor and a feeding belt conveyor. The structure diagram is shown in the figure.

1. Feeding belt conveyor 2. Collecting belt 3. Feeding belt 4. Cold storage bin

 

Each independent bin of the cold aggregate supply system adopts a modular design, which is convenient for transportation, installation and disassembly. During installation, it is connected with the bin support frame as a whole. The door opening mechanism of the bin adopts manual adjustment. If the aggregate gradation needs to be adjusted, there are two adjustment methods, namely, changing the opening of the cold bin door or adjusting the belt speed of the feeding belt to meet the requirements. Each bin is covered with a grille net, which can filter out excess aggregate when the loader dumps aggregate into the bin, and at the same time can alleviate the impact of aggregate on the bin. The outer wall of the sand bin is equipped with a vibration motor, which can make the sand fall smoothly and prevent arching. The cold storage bin can only be started when the relevant equipment is ready to accept the aggregate. The start of the cold bin motor depends on the working conditions of other motors in the mixing plant (such as drying drums, dust collectors, etc.). Therefore, the cold storage bin can only be started after the above-mentioned motor is started.

 

 Drying system

The drying system is one of the main components of the asphalt concrete mixing plant. Its main function is to heat and dry the aggregates and heat them to the temperature required to obtain high-quality asphalt concrete. In order to remove the moisture in the aggregate, the drying system must provide a certain amount of heat, and its caloric value varies according to the different specifications of the drying drum, so that the moisture in the aggregate can be dried and converted into water vapor. Heat the aggregate to the required temperature.

The drying drum is a rotating, long cylindrical barrel structure (as shown in the figure). The aggregate from the feeding belt of the cold bin unit enters the drum from the feed box, and is dried in direct contact with the gas generated by the burner, and at the same time it is heated to a set temperature, and flows out from the aggregate outlet chute into the hot aggregate Lifting machine.

1. Burner 2. Aggregate outlet chute 3. Drying drum 4. Bracket 5. Drive device 6. Feed box A. Flue gas

 

The cylinder of the drying drum is coiled and welded by heat-resistant and wear-resistant boiler steel plates, and its thermal expansion is consistent before and after heating, which can prevent deformation caused by high temperature. There is an inclined angle between the bracket of the cylinder and the horizontal plane, and the purpose is to make the drying cylinder in an inclined position when it is working, so that the aggregate moves forward continuously during the repeated lifting process in the drum and flows to the discharge end.

 

The internal structure of the drying drum is divided by function to four parts:

1. Feeding area. The blades in this part are spiral blades whose function is to push the aggregate into the drum and move forward quickly.

2. Heat exchange area. In order to strengthen the heat exchange between the fuel gas and the aggregate, the design of the blades allows the aggregate to be lifted and scattered freely here many times to form a uniform material curtain, so that the gas can fully pass through the material curtain and exchange heat with the aggregate.

3. Burning zone. In order to make the fuel fully combust, a special heat absorption lifting system is equipped in this section. It can make the aggregates be lifted up and close to the inner wall of the cylinder during the forward movement without falling to block the flame, and at the same time, it can achieve the purpose of heating the aggregates inside the drum. Moreover, it can also reduce the loss of mechanical incomplete combustion caused by the fuel droplets being knocked off by the aggregate, reduce the loss of heat dissipation through the drum wall, and reduce the damage of heat radiation to the drum wall.

4. Discharge area. It quickly lifts the aggregate into the discharge box and discharges it out of the aggregate outlet chute.

 

Dust removal system

The function of the dust removal system is to collect and process the combustion exhaust gas generated in the drying drum and the dust generated in other devices, and discharge gas that meets the requirements of environmental protection. It consists of a first-stage flue, a first-stage gravity dust collector, a second-stage bag filter, a second-stage flue and an induced draft fan. Larger particle size dust is separated and collected by the gravity dust collector, and the bag filter filters the fine dust. In order to facilitate transportation, installation, and compact structure, the first-stage gravity dust collector and the second-stage bag filter are integrated as a whole during production, as shown in the figure.

1. Drying drum 2. Flue 3. Temperature sensor 4. Gravity dust collector

5 Bag dust collector 6. Induced draft fan 7. Chimney A. Smoke

 

The dust removal system operates in a negative pressure environment, and the air pressure and air volume are controlled by adjusting the opening of the air door of the induced draft fan. The coarse dust collected by the gravity dust collector is discharged through the gravity ash unloading valve and sent to the hot aggregate elevator by the screw conveyor. The fine dust collected by the bag filter is sent to the recovery hoist through the screw feeder. The dust generated in the links of lifting, vibration, metering, and mixing flows into the primary flue through the exhaust pipe. The air purified by the bag filter is discharged to the atmosphere from the chimney.

4.Filler system

The filler system is one of the main components of the asphalt concrete mixing plant. Its main function is to store raw filler and recycle the recycled filler. There are two powder tanks, one for adding new mineral powder and the other for recycling dust collector Filter dust. The two powder tanks are composed of a tank body, a powder elevator, a transition powder hopper, and a powder adding screw conveyor. The two powders can be weighed and stirred by a screw conveyor in a certain proportion to the upstairs mixer, which can respectively complete the functions of lifting, storing and conveying new powder and recycled powder.

Hot aggregate lifting system

The function of the hot aggregate hoist is to lift and transport the dried hot aggregate from the drying drum to the vibrating screen located at the uppermost part of the main mixing building.

 

The hot aggregate elevator is mainly composed of the following parts:

1. Upper section: It is composed of upper casing, upper cover and transmission sprocket set.

2. Lower section: It is composed of lower casing and tensioning sprocket. The lifting chain is tensioned with a screw and spring adjustment method, which can automatically adjust the rotation slack phenomenon caused by chain wear, and can buffer the additional stress caused by sudden impact load. The sprocket is an assembled structure with a detachable rim, which has a long service life and is convenient for maintenance and replacement.

3. The middle section: It is composed of the middle casing for supporting, protecting and sealing. The middle casing is a standard section structure.

4. Drive device: shaft-mounted helical gear reducer motor (with brake) integral drive device.

5. Operation part: It is composed of hopper, round return chain, chain link hook, etc. The traction parts adopt high-strength circular chain, which is made of high-quality low-carbon alloy structural steel, which has high tensile strength and wear resistance after heat treatment, so it has reliable performance and long life. Lift buckets are installed equidistantly on the chain.

 

Vibrating Screen System

The vibrating screen is a device that classifies the hot aggregate delivered by the hot aggregate elevator and sends it to the hot aggregate bin. After the hot aggregate enters the screening machine, it is sieved into five specifications, and enters the five bins of the hot aggregate storage bin respectively. The top of the vibrating screen is equipped with a distribution valve, and the hot aggregate can directly enter the bypass bin without being screened.

1- vibrator; 2- screen box; 3- damping support device; 4- motor drive device; 5- dust cover; 6-distribution valve

 

The structure of the vibrating screen is a self-synchronizing two-axis linear type, which is composed of five parts: a vibrator, a screen box, a vibration damping support device, a motor transmission device, and a dust cover.

The screens are all woven screens, tensioned front and back. It adopts a five-layer five-segment screen structure, the screen is stretched longitudinally, and 4-5 layers of screens are installed inside the vibrating screen. The standard screen meshes configured at the factory have apertures of 3, 6, 11, 22, 35 mm, and users can configure corresponding screens according to production needs.

The screen is an important part of the vibrating screen. The correct selection and use of high-quality wear-resistant screens can ensure the precise gradation of the mixture and prevent the occurrence of mixing. The wear-resistant screen is braided by high-carbon and high-manganese steel wire. It has good wear resistance but relatively poor fatigue resistance. Tensing the screen during use is the key to avoiding abnormal early damage and ensuring the service life of the screen.

Reasonable selection of matching screen specifications is particularly important to ensure output and screening quality. The usual principle of sieve allocation is: the maximum sieve size is determined according to the specification for the maximum particle size; the smallest and second-smallest sieve sizes are determined from reaching the requirements of the right section of the easy-to-control grade wiring; the remaining sieve sizes should be determined It is determined that the distribution of each silo is as balanced as possible.

 

Metering system

The metering system is a device that measures aggregate, powder and asphalt according to the ratio of the asphalt mixture and discharges them into the mixer from the discharge gate or valve.

The metering system includes aggregate scale, asphalt scale and powder scale. The discharge door or valve is driven by a cylinder to open and close.

 

Mixing system

The mixer is a device that mixes and discharges the aggregate, powder and asphalt separately input in the set order after the production mix ratio is measured. The structure of the mixer is a double-horizontal shaft type. The two agitating shafts are forced to be synchronized by a pair of identical gears that mesh with each other. The speeds are equal and the rotation directions are opposite. Multiple stirring arms are installed on the shaft, and the end of the arm is bolted to the wear-resistant blade. The mixed asphalt mixture is discharged from the discharge gate at the bottom.

Finished material storage system

The finished material is discharged from the discharging door of the mixer, and sent to the finished product silo by the transport trolley for temporary storage. Because it is a batch equipment, that is, weighing and stirring are carried out in batches, about 45 seconds is a production cycle, and the running rhythm of the material transport trolley is consistent with it, so the finished material lifting and storage system is used to quickly and timely mix the mixed material Ground storage is the guarantee for the equipment to improve high productivity.

Under special circumstances, the transportation vehicle may directly enter the bottom of the mixing tank to receive materials. Before the vehicle enters the receiving material, the trolley should be manually operated and positioned outside the mixing building, and the front running track should be raised to a horizontal position with an electric hoist.

 

Asphalt heat transfer oil heating system

The working principle of the asphalt heat transfer oil heating system is: the heat transfer medium heat transfer oil in a closed circulation system absorbs the heat released when the diesel is burned from the burner to increase the temperature, and the high temperature heat transfer oil heats the asphalt through the circulation pipeline and For asphalt pipelines, the cooled heat transfer oil is heated again, and the cycle continues until the asphalt and pipeline reach the required temperature. Because the burners of most systems are controlled by programmable controllers (PLC) and have stable performance, the asphalt heat-conducting oil heating system can also be called "unmanned automatic heating system". To make it safe and reliable to maximize its benefits, correct use and maintenance are the key.

This device uses an automatic burner to heat the heat transfer oil to 180-210°C, and uses a circulating pump to heat and heat the asphalt tank, asphalt metering bin, heavy oil heater, heavy oil tank, and asphalt and heavy oil pipelines. Wait until heated to the desired temperature.

Pneumatic control system

The pneumatic control system is mainly used to control the actions of various weighing hopper doors, discharge doors, valves and other devices. The operating status of the gas path control system will directly affect the output accuracy and performance of the mixing equipment.

The air circuit control system is mainly composed of four parts: air source, control element, executive element and auxiliary element.

Air source: It is an energy device to obtain compressed air. The main part is air compressor, refrigeration dryer, air storage tank, etc.

Control element: An element used to change the direction, pressure, and flow of compressed air to achieve the specified actions of the actuator. Such as: solenoid valve, quick discharge valve, etc.

Actuator: It is an energy conversion device that uses compressed air as the working medium to generate mechanical motion and convert the pressure energy of the gas into mechanical energy. In this equipment, the actuator is mainly a cylinder, and it is a double-acting cylinder.

Auxiliary components: some devices needed to purify, lubricate, muffle the compressed air and connect between components. Auxiliary components include gas source processing components, gas pipelines, joints, etc.

Burner

The imported integrated burner is a professional burner designed according to the special requirements of the asphalt mixing station for the burner. The burner adopts a combustion body and a blower integrated chassis design to ensure the reliability of different working environments With regard to safety and safety, mechanical ratio or electric ratio adjustment can be used according to user needs, and the air/fuel ratio can be precisely adjusted to ensure the best combustion efficiency, thereby ensuring the quality of asphalt products and the economy of the mixing plant.

The burner is controlled by the program controller + temperature control instrument to control the ignition process and automatically adjust the opening of the throttle according to the set temperature.

 

Basic structure of control system

The asphalt control system mainly includes upper computer monitoring and management software, PLC control program, and line control of hardware equipment. Specifically divided into: power control part, cold material grading control part, burner control part, dust removal control part, automatic metering control part, finished material lifting part, asphalt supply part, upper computer software part, each part is centralized and controlled by PLC Output.

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