Asphalt distributor is the core special equipment in road maintenance, synchronous sealing layer, adhesive layer construction and waterproof adhesive layer construction. It mainly undertakes the storage, transportation, heating and spraying of liquid asphalt and emulsified asphalt. Equipment long-term in high temperature, oil, dust, frequent start-stop complex conditions, pipeline easy to block, hydraulic loss, electrical components easy aging. Standardized daily maintenance and maintenance can effectively reduce the failure rate of equipment, prolong the service life of the whole machine, ensure the uniformity of distribution and construction quality, and avoid potential safety hazards such as high temperature scald, oil leakage and fire. This paper systematically combs the complete set of maintenance precautions for asphalt spreader, and provides standardized reference for field equipment operation and maintenance personnel. 

Precautions for daily basic maintenance 

Daily maintenance is the basis for reducing overhaul faults and ensuring stable operation of equipment. It is necessary to insist on daily normal inspection before and after shift to eliminate operation with faults. 

Pre-shift appearance and tank inspection 

Before daily construction, check whether the asphalt tank body has deformation, leakage and open welding phenomenon, and whether the insulation layer of the tank body is intact, so as to eliminate the risk of leakage of high temperature asphalt. Check whether the sealing gasket of manhole, feed inlet and drain outlet of tank is tight, so as to prevent overflow of feed material, rapid heat dissipation and dust and sundries from entering into tank to pollute asphalt raw material. At the same time, check whether the fastening bolts, brackets and connecting parts of the whole vehicle are loose, and tighten and reinforce them in time to avoid falling off of parts caused by long-term vibration. 

Cleaning operations 

Asphalt solidification and caking are the main causes of equipment clogging. After finishing work every day, the sprinkling rod, nozzle, filter and feed filter screen must be thoroughly cleaned. Remove asphalt residue and dust attached to the vehicle body in time. Forced dredging, hard prying and hard smashing are prohibited after the residue dries, so as to avoid nozzle deformation, pipeline cracking and filter screen damage. For long-term shutdown, residual asphalt in the tank shall be emptied, and the pipeline system shall be cleaned to prevent asphalt from freezing and blocking the pipeline at low temperature. 

Level and oil inspection 

Regularly check the liquid level of hydraulic oil, lubricating oil and diesel oil to ensure sufficient oil and clear oil. If oil is found to be turbid, emulsified and excessive impurities, replace it in time. Fill the matching oil strictly according to the equipment label. It is forbidden to mix different types of hydraulic oil and lubricating oil, so as to avoid the failure of hydraulic system wear, insufficient pressure and action stagnation. 

Heating system maintenance precautions 

Heating system is the core and key system of asphalt distributor, which directly determines asphalt fluidity and distribution effect. It is also the concentrated area of high temperature safety hazard. Maintenance and maintenance shall strictly abide by high temperature operation specifications. 

temperature control specification 

The heating temperature of asphalt shall be strictly controlled. The temperature control standards for matrix asphalt, emulsified asphalt and modified asphalt shall be distinguished. Overtemperature dry burning and local overheating shall be prohibited to prevent asphalt aging and deterioration, tank deformation at high temperature and combustion hazards. During heating process, personnel are forbidden to stay close to the burner and tank heat dissipation port to prevent high temperature scald. The temperature control protection device and temperature sensor shall not be removed at will during equipment operation to ensure the accuracy and sensitivity of the temperature control system. 

Burner periodic maintenance 

Regularly clean up carbon deposit, oil stain and blocked impurities of burner, check atomization state of fuel injection, ignition device and fan operation state to ensure sufficient combustion, no black smoke and no tempering. If ignition failure, unstable combustion and slow temperature rise are found, stop the machine to check oil circuit blockage, filter element blockage, fan failure and other problems, and prohibit continuous operation with fault. 

Heat transfer oil system maintenance 

Regularly check the heat transfer oil pipeline for leakage, aging, bulging phenomenon, check the heat transfer oil level, timely supplement, regular replacement of heat transfer oil. It is forbidden to operate without heat transfer oil, so as to avoid pipeline dry burning and local high temperature cracking, which may cause asphalt leakage and fire accident. 

Precautions for maintenance of pipeline and spraying system 

Spraying system directly determines the construction flatness and distribution uniformity. Pipeline blockage, nozzle failure and valve failure are high-frequency problems on site. Maintenance operations need to be standardized. 

Nozzle maintenance and replacement 

Regularly dredge and inspect the spraying nozzles one by one, clean the asphalt caking inside the nozzles, check the atomization state of the nozzles, and replace them in time if they are found to be worn, deformed, blocked and atomized unevenly. Replacement of nozzles must be carried out after equipment shutdown, pressure relief and temperature reduction. It is forbidden to disassemble parts under high temperature and pressure to prevent injury caused by asphalt spray. 

Pipeline and valve maintenance 

Check asphalt pipeline, flange, sealing gasket, ball valve and three-way valve regularly. Replace and repair gasket aging, pipeline leakage and valve jam in time. Start circulation system before operation to fully circulate and preheat asphalt, ensure smooth pipeline and uniform temperature, and avoid partial cold material to cause material distribution and uneven thickness. For long-term parking, all valves must be closed and pipelines must be blocked for dust protection. 

Filter system maintenance 

Asphalt filter and feed filter screen shall be cleaned daily and replaced regularly to prevent impurities from entering pipeline and nozzle and causing blockage. It is forbidden to dismantle the filter screen and filter for direct operation, so as to prevent large particles of impurities from wearing the asphalt pump and blocking the spraying system, resulting in large-scale construction quality defects. 

Hydraulic and transmission system maintenance precautions 

Hydraulic system provides power for asphalt pump, sprinkling rod and lifting mechanism, and is the power core of stable operation of equipment. Maintenance should pay attention to sealing and pressure stability. 

Hydraulic system inspection 

Regularly check hydraulic pipelines, joints, oil cylinders for leakage, bulging, cracks, oil leakage, pressure relief found timely shutdown treatment. Check whether the pressure of hydraulic system is normal. Check whether the pressure is too high or too low. Check whether the pressure regulating valve, oil pump and oil circuit are blocked. Do not operate under overpressure. 

Asphalt pump maintenance 

Asphalt pump is the core component of transportation, so it is necessary to fill lubricating grease regularly, check the operation sound and vibration state of pump body, and timely repair abnormal sound, jamming and insufficient transportation flow. It is forbidden to idle and dry grind the pump body. Before starting, it is necessary to ensure that there is medium in the pipeline or complete the preheating cycle to avoid wear and scrap of the pump body. 

Fastening of transmission parts 

Regularly check the tightness and wear of coupling, transmission belt and fixed bracket, adjust belt tightness in time, replace worn parts, and prevent unstable distribution caused by transmission slip and insufficient power. 

Electrical control system maintenance precautions 

The electronic control system is responsible for equipment start-up and shutdown, temperature control, distribution metering and automatic control. The failure rate is high, the maintenance risk is high, and the maintenance needs to strictly abide by the electrical safety specifications. 

Principle of outage maintenance 

All electrical maintenance, circuit replacement and controller debugging must be carried out after complete power failure and shutdown. It is forbidden to plug in and disconnect the circuit and repair components with live electricity to prevent short circuit, electric shock and controller burning. 

Line and component protection 

Regularly check the whole vehicle circuit, plug, sensor and controller, clean the oil stain and dust on the surface of the circuit, check whether the insulation layer of the circuit is aged and damaged, wrap up and replace the damaged circuit in time, and eliminate short circuit and leakage fault. Heat insulation protection shall be done for lines in high temperature area to avoid high temperature baking aging. 
Instrument and measurement calibration: regularly check temperature control instrument, pressure instrument and spraying metering system to ensure accurate data. Instrument failure and data inaccuracy need to be calibrated or replaced in time to avoid quality problems such as excessive spraying amount and substandard construction thickness caused by parameter deviation. 

Safety maintenance contraindications 

Asphalt distributor has multiple risks of high temperature, high pressure, fuel oil and asphalt medium. Illegal operation is strictly prohibited during maintenance to eliminate safety accidents. 
It is strictly prohibited to disassemble the pipeline, remove the nozzle and open the access port when the equipment is under high temperature and pressure, so as to prevent high temperature asphalt spray scald; it is strictly prohibited to directly water the tank and pipeline under high temperature to avoid pipeline explosion and tank deformation; it is strictly prohibited to stack flammable sundries and oils around the equipment, and prevent open fire from approaching the operation area; it is strictly prohibited to operate the equipment with faults and force the construction when the protection device fails; it is strictly prohibited to modify the parameters of the pipeline, oil circuit and temperature control system without permission. 

Seasonal and long-term downtime maintenance precautions 

Low temperature maintenance in winter 

After winter construction, the residual asphalt in the tank must be completely emptied, and all pipelines must be cleaned to prevent asphalt from solidifying and cracking pipelines and pump bodies; replace and adapt winter low-temperature oil products, check the state of antifreeze, and do a good job of insulation protection for the whole vehicle to avoid freezing damage to equipment parts. 

Long-term parking maintenance 

When the equipment is idle for a long time, it is necessary to clean the whole vehicle, vent the medium, do a good job of rust prevention and corrosion prevention, apply rust prevention oil to the exposed metal parts, disconnect the power supply, cover the protection, and start the trial operation regularly to prevent the aging and stagnation of the parts. 

sum up 

The core of asphalt distributor maintenance lies in "frequent cleaning, frequent inspection, high temperature control, prohibition of violations, anti-blocking". Strict implementation of daily maintenance, system maintenance and safety operation specifications can not only effectively reduce equipment failure rate, reduce maintenance cost, prolong equipment service life, but also ensure uniform and stable asphalt distribution, construction quality up to standard, avoid safety accidents such as scald, leakage, fire and equipment damage, which is an important guarantee for standardized and refined management of road maintenance equipment.