Asphalt mixing plant is the core complete set of equipment for large-scale and standardized production of asphalt mixture in road engineering. It integrates aggregate batching, drying and heating, screening and metering, asphalt spraying, mixing and molding, dust removal and environmental protection. Its installation quality directly determines the mixture production accuracy, equipment operation stability, construction efficiency and service life.The asphalt station installation process is complicated, the equipment components are numerous, the hoisting operation is intensive, and the electromechanical coordination degree is high. Therefore, the standardized construction logic of "foundation first, main engine first, auxiliary engine first, machinery first, electrical first, single machine first, linkage first" must be followed.Combined with industry specifications and field operation experience, this paper systematically combs the complete process of asphalt mixing plant from preliminary preparation, foundation construction, equipment hoisting, system installation, commissioning and operation to completion acceptance, clarifies the technical points and quality control standards of each link, and provides technical reference for standardized installation and construction of engineering site.

Preparatory work for installation

The preliminary preparation is the basis for ensuring the efficient, orderly and compliant installation of asphalt station. The core is to complete the four preparations of site, technology, materials and personnel, so as to eliminate construction rework and potential safety hazards.

Site selection and leveling

In combination with the site selection of the general construction plan, the area with flat terrain, solid geology, convenient transportation and far away from residential areas shall be preferentially selected to meet the requirements of raw material stacking, equipment layout, finished material transportation and fire evacuation.Strictly implement the "three connections and one leveling", complete the site water supply, electrification, access and site leveling and compaction, replace the soft foundation, compaction or pile foundation reinforcement treatment, so as to avoid uneven settlement, resonance offset and other problems during the operation of equipment.At the same time, the exclusive areas for dust removal equipment, asphalt tank, fuel oil system and waste stacking shall be planned to realize clear functional zoning and smooth pipeline layout.

Technical disclosure and drawing review

Organize technicians, installation teams and supervisors to carry out joint review of drawings, review the compatibility of equipment foundation drawings, embedded parts drawings, electromechanical wiring drawings with site working conditions, and define core parameters such as foundation size, embedded parts position, equipment installation elevation, levelness and verticality.Special technical disclosure shall be made for hoisting parameters and installation deviation standards of key components such as main building, drying drum and hot silo of large asphalt mixing plant, so as to unify construction standards and clarify quality acceptance requirements.

Material and equipment preparation

Check the complete set of equipment components, including core components such as cold material supply system, drying and heating system, lifting and screening system, mixing main building, asphalt supply system, powder material system, dust removal and environmental protection system, electric control system, finished product bin, etc., check the integrity of accessories, fasteners, seals and pipelines, and timely report for replacement of deformed, damaged and missing components.Equipped with crane, welding machine, level, theodolite, torque wrench, calibration balance, vacuum pump and other installation tools in advance, ready for rain, dust, protection safety consumables.

Personnel and security preparations

Professional installation teams shall be set up, and special types of work such as lifting, electrician and welder shall be certified.Pre-job safety training shall be carried out, with emphasis on safety specifications for aerial work, large-scale hoisting, electrical work and inflammable and explosive medium construction, warning zones for hoisting operation shall be designated, protective platforms for aerial work and safety rope fixing points shall be erected, and safety protection measures for all personnel shall be implemented.

Equipment foundation construction and maintenance

Foundation construction is the core of asphalt station installation quality, which directly determines the operation stability of equipment. Standardized construction shall be carried out in strict accordance with drawings to eliminate settlement, deviation and cracking.The mainstream asphalt mixing plant adopts raft independent foundation, and the foundation of each equipment shall ensure the same horizontal datum to reduce the resonance influence of equipment operation.
Complete procedures of foundation construction: site setting out → foundation pit excavation → foundation compaction and leveling → reinforcement binding → precise positioning and fixing of embedded parts → formwork support → concrete pouring → vibration compaction → film curing.
Core quality control points during construction: firstly, embedded parts and embedded bolts must be accurately positioned, elevation and axis deviation shall be controlled within the specification range, and real-time review shall be carried out during concrete pouring to prevent deviation; secondly, foundation concrete shall be vibrated evenly and densely without honeycomb, pockmark, cavity and other quality defects; Third, strictly control the curing period, curing at normal temperature for no less than 7 days, heat preservation measures shall be taken in winter low temperature environment, and equipment installation shall be carried out only after the concrete strength reaches 100% of the design strength, and lifting construction in advance is strictly prohibited.At the same time, the foundation settlement observation shall be carried out to ensure that the bearing capacity of the foundation meets the requirements of full-load operation of equipment.

The installation process of core main equipment

Follows the lifting and installation sequence of "from bottom to top, from heavy to light, first main and then auxiliary", and completes the installation of each system equipment in turn, correcting the levelness, verticality and coaxiality throughout the process to ensure the matching accuracy of equipment.

Cold material supply system installation 

First install the cold bin rack and hopper, adjust the rack levelness, fix the anchor bolts, and ensure that the bin as a whole is stable without shaking. Then install frequency conversion speed regulation belt conveyor, aggregate belt conveyor, calibrate belt conveyor roller coaxiality, adjust belt tightness, ensure belt smooth operation, no deviation, no slip phenomenon. Install hopper door, frequency conversion control system, debug the flexibility of opening and closing of material door, ensure accurate and controllable aggregate batching. After installation of cooling system, clean up internal sundries and make anti-corrosion and anti-rust treatment of rack. 

Drying heating system installation 

Drying drum for large rotary heavy equipment, installation accuracy requirements are extremely high. Lift and fix the drying drum bracket and supporting wheel group, accurately adjust the spacing, levelness and parallelism of supporting wheels to ensure uniform stress. A large crane is used to lift the drying cylinder as a whole. After slowly positioning, the inclination, concentricity and rotation center of the cylinder are accurately corrected to ensure smooth rotation of the cylinder without stagnation and deviation. 
After the cylinder is fixed, install the wheel belt, stop wheel, transmission gear and reduction motor, add special lubricating grease, adjust the transmission clearance and meshing accuracy. Finally, install the burner, install it strictly according to the center line, connect the fuel pipeline, combustion air pipeline, ignition control system and flame detection safety device, and do a good job in pipeline sealing test to eliminate oil leakage and air leakage hidden dangers. 

Installation of hot material lifting and screening system 

First install the frame and barrel of the hot material elevator, correct the verticality of the frame, fix the anchor bolts, install the lifting hopper, chain and driving sprocket, adjust the tension of the chain to ensure smooth lifting operation. Then install vibration screening equipment, accurately fix the screen body support and shock absorber, ensure that the shock absorber is evenly stressed and horizontally consistent, and avoid severe vibration and deviation during screening. Install standard screen, check the flatness and tension of screen surface, seal the inlet and outlet of screening machine to prevent dust leakage of hot aggregate. 

Mixing Main Building Core Installation 

The main mixing building is the core metering mixing unit of asphalt station, and the installation accuracy directly determines the mixture mixing accuracy. Complete the hoisting and installation of main building column, frame, hot bin, metering hopper, mixing cylinder and discharge door in turn. The overall verticality deviation of the main building shall not be greater than 1‰ of the total height, and the horizontality deviation shall be strictly controlled within the allowable range of the specification. 
Focus on calibrating the sensors of aggregate metering, powder metering and asphalt metering systems to ensure that the metering base is horizontal, the force is uniform, and the sensors are free of offset and stagnation. Install mixing arm and mixing blade, position strictly according to standard angle, ensure mixing uniformity, adjust discharge door sealing structure, and eliminate leakage and slurry leakage problems. Complete the sealing treatment of the main building, seal the gaps of equipment, and reduce heat loss and dust pollution. 

Powder supply system installation 

Install powder bin support, bin body, fixed dust removal respirator, arch breaking device and screw conveyor. Calibrate the inclination and concentricity of screw conveyor to ensure smooth powder conveying, no blockage and no accumulation. Install powder metering device and debug frequency conversion conveying system to ensure accurate and controllable powder supply. Check the sealing performance of powder bin to prevent rainwater infiltration and powder dust leakage, and ensure the dryness and cleanliness of mineral powder. 

Installation of asphalt supply system 

Install asphalt storage tanks, insulation heating systems, asphalt pumps, filters, spray lines and spray rods. Heat preservation and sealing treatment shall be done for pipelines in the whole process, and pressure sealing test shall be carried out for all asphalt pipelines to eliminate leakage hidden danger. Adjust asphalt heating temperature control system to ensure accurate and controllable temperature and avoid asphalt aging and condensation blocking. 

Auxiliary system supporting installation

Dust removal environmental protection system installation

At present, bag dust removal system is adopted as the mainstream of asphalt station, and dust removal box, filter bag, ash cleaning device, induced draft fan and exhaust pipe are installed.Calibrate the coaxiality of induced draft fan and adjust the damping device of fan to ensure low noise and stable operation.Check filter bag installation integrity and tightness, debug pulse ash cleaning control system to ensure dust removal efficiency meets standards and environmental protection emission requirements.Connect the dust removal pipeline, seal and fix the pipeline to avoid air leakage and dust.

Finished product bin system installation

Hoist finished product bin rack, bin tank, discharge gate, insulation device, calibrate the horizontal and vertical degree of rack, fix firmly.Adjust the hydraulic control system of discharge door to ensure flexible opening and closing, tight sealing, and prevent cooling, segregation and leakage of finished materials.Install thermal insulation layer and anti-blocking device of bin to ensure stable storage temperature of finished asphalt mixture.

Electrical and control system installation

Install main control distribution cabinet, field distribution box, operation console, sensor and cable tray, lay cables in a standardized manner, and make sure that the lines are protected against water, dust and abrasion.Wiring strictly according to electrical drawings, distinguish between strong and weak current lines, do a good job of grounding zero protection, and eliminate leakage and short circuit hidden dangers.Install automatic control system, industrial control display screen, frequency conversion control module, access to various equipment signals, to ensure that the whole machine linkage controllable.After wiring is completed, check the on-off and insulation performance of the lines one by one, and complete the commissioning of the electrical system.

Hydraulic and pneumatic system installation

Install hydraulic pump station, oil cylinder, pneumatic solenoid valve and air pipe, clean impurities in pipeline and arrange pipeline according to specifications.Fill standard hydraulic oil, adjust system pressure, check pipeline for leakage and stable pressure.Test the flexibility of each cylinder and oil cylinder to ensure the accurate and synchronous movement of discharge door, bin gate and adjusting mechanism.

Commissioning and test run of complete machine

After all the equipment is installed, it needs to go through three stages: single no-load commissioning, whole machine linkage no-load commissioning and load trial production with materials to comprehensively verify the installation quality and operation performance of the equipment.

Single unit no-load commissioning

Conduct single-unit inching commissioning for cooling system, drying system, lifting and screening system, stirring system, powder system, dust removal system and asphalt system one by one, check equipment operation direction, operation state and transmission accuracy, and check abnormal sound, jamming, deviation, leakage and other problems.Calibrate each metering sensor and variable frequency speed regulation parameters to ensure stable operation and accurate parameters of single machine.

No-load debugging of whole machine linkage

Start the automatic control system, carry out the whole machine linkage no-load operation, simulate the complete production process, verify the synchronization of each equipment linkage, control system response speed, interlock protection function.Check vibration, noise and temperature rise of the whole machine, optimize equipment operation parameters, correct installation deviation and linkage defects.

Load Trial Production with Material

After the no-load commissioning is qualified, carry out the trial production with small load, debug the core parameters such as aggregate proportion, drying temperature, asphalt dosage and stirring time in turn, and check whether the mixture gradation, asphalt content and mixing uniformity meet the standards.Optimize equipment parameters according to trial production results, solve problems such as blocking, segregation, uneven temperature, measurement deviation, etc. in the production process until the equipment is continuously and stably produced and the product quality meets the standard.

Closing rectification and completion acceptance

After commissioning is qualified, carry out site finishing work, clean up sundries inside equipment and garbage on construction site, comprehensively recheck and tighten bolts, welds, pipelines and sealing parts of equipment, supplement anti-corrosion and anti-rust coatings, and improve equipment identification and safety warning signs.Sort out a complete set of construction data, including drawings, technical disclosure records, foundation construction records, equipment installation records, commissioning reports, inspection records, etc.
Organize the construction unit, supervision unit and construction unit to jointly complete the acceptance, verify the equipment installation accuracy, operation stability, environmental protection compliance and safety compliance, and formally put into batch production after passing the acceptance.

Key points of installation construction quality and safety control

Quality control core points

First, strictly control the quality of foundation construction to eliminate uneven settlement; second, the hoisting of large components must be accurately aligned, and the installation deviation of verticality, levelness, and coaxiality must be strictly controlled; third, the installation and calibration of the metering system must be accurate, ensuring the accuracy of mixture ratio from the source; Fourth, all seals and pipeline connection parts are tight and reliable to eliminate the problems of material leakage, oil leakage, air leakage, and dust; Fifth, the wiring and pipe layout of electrical and hydraulic systems are standardized, and parameter debugging is accurate.

Safety and environmental protection control points

Safety protective equipment must be worn for aerial work, and reliable working platform must be set up; special personnel shall be assigned for command of large-scale lifting operation, and warning area shall be designated; electrical operation shall strictly implement power-off operation specification; open fire is prohibited in asphalt and fuel oil area, and sufficient fire-fighting equipment shall be equipped.Construction waste and waste oil shall be collected and treated uniformly, and environmental protection control shall be implemented throughout the installation process to prevent dust and waste liquid pollution.

Conclusion

Asphalt mixing plant installation is a systematic and refined engineering construction work, covering many professional fields such as civil engineering foundation, mechanical hoisting, electromechanical integration and system commissioning.Installation quality not only affects equipment operation efficiency and failure rate, but also directly determines asphalt mixture production quality and road engineering construction quality.During the construction process, the standardized installation process must be strictly followed, the construction precision and quality details of each process must be strictly controlled, the safety and environmental protection control requirements must be implemented, and the long-term stable, efficient and compliant operation of asphalt mixing plant shall be ensured through standardized installation and fine commissioning, so as to provide reliable equipment and quality guarantee for asphalt pavement construction of road engineering.