As we all know, asphalt mixing equipment is a key equipment for asphalt pavement construction. The installation and commissioning of this mixing equipment directly affects its operating status, road construction progress and quality. This article will mainly talk about the technical points for the installation and commissioning of large-scale asphalt mixing equipment.
Selection
Adaptability
According to the qualification of the enterprise, the scale of the contracted project, the amount of tasks of this project (the bid section), combined with factors such as the climate of the construction area, the number of effective construction days, the development prospects of the enterprise, and the economic strength of the enterprise, a comprehensive study should be made to select the equipment model. 20% larger.
Advanced
The selected equipment should have a technical level that meets the current construction requirements and has scalability. For example, the number of cold and hot bunkers should be six to meet the precise control of the mix ratio; the mixing tank should have an interface to add additives to meet the requirements of additives such as fiber materials and anti-rutting agents.
Environmental protection
When purchasing equipment, you should fully understand the environmental protection indicators of the equipment to be purchased, which should meet the requirements of national environmental protection regulations and the requirements of the environmental protection department in the region of use. In the purchase contract towel, the environmental protection emission requirements of the heat transfer oil boiler and the dust collector device of the drying system should be clarified. The equipment operation noise should comply with the national regulations on the enterprise boundary noise. The asphalt storage tank and heavy oil storage tank should be equipped with various spilled smoke Gas collection and treatment facilities.
installation
The installation work is the basis for deciding the quality of the equipment. It should be highly valued, carefully organized, and implemented by experienced engineers.
Ready to work
The main preparations include the following 6 items: one is to entrust a qualified architectural design unit to design the basic construction drawing according to the floor plan provided by the manufacturer; the second is to apply for distribution and transformation equipment according to the requirements of the equipment instruction manual, and to calculate the distribution capacity Should consider the electricity requirements of supporting equipment such as emulsified asphalt and modified asphalt, and leave 10% to 15% of the surplus passengers; the second is that the residential electricity must be installed with a transformer of appropriate capacity to ensure the stable operation of production equipment The fourth is that the high and low voltage cables in the site should be designed as a buried method, and the distance between the transformer and the main control room should be 50m. The fifth is that it takes about 3 months to complete the power installation procedures. It should be processed as soon as possible after the equipment is ordered to ensure commissioning. When electricity is used; sixth, boilers, pressure vessels, measuring equipment, etc. must be processed in time for relevant approval and inspection procedures.
Installation process
Foundation construction The basic construction procedures are as follows: review drawings → lofting → excavation → foundation tamping → reinforcement ligation → installation of embedded parts → formwork → silicon pouring → maintenance.
The foundation of the mixing building is generally designed as a raft foundation. The foundation must be treated flat and dense. If the soil is loose, it must be replaced. It is strictly forbidden to use the pit wall to directly cast the underground foundation, and the formwork must be installed. If the average temperature is less than 5 ℃ for 5 consecutive days and nights during construction, thermal insulation measures shall be taken according to the winter construction requirements (such as foam board in the formwork, heating and insulation of the scaffold, etc.). The installation of embedded parts is a key process. The plane position and height must be accurate, and the fixing should be firm to ensure that the embedded parts do not move or deform during the vibration of the pouring.
After the foundation construction is completed and the acceptance conditions are met, the foundation acceptance must be carried out. During the acceptance, the rebound strength is used to measure the concrete strength, the total station is used to measure the plane position of the embedded parts, and the level is used to measure the basic elevation. After the acceptance, the hoisting process is entered.
Hoisting construction The hoisting construction process is as follows: mixing building → hot material lifting equipment → powder silo → powder material lifting equipment → drying drum → dust collector → belt conveyor → cold silo → asphalt tank → thermal oil furnace → main control room → annex.
If the legs of the finished product silo of the first floor of the mixing building are designed as pre-embedded bolts, the strength of the concrete poured twice must reach 70% before the above layers can be hoisted. The lower stair guardrail must be installed in time and should be firmly installed before it can be hoisted upwards layer by layer. For the parts that cannot be installed on the guardrail, hydraulic lift trucks should be used for operation, and safety facilities should be equipped to ensure safety. When choosing a crane, its lifting quality should meet the requirements. Before the lifting operation, it must be fully communicated and communicated with the lifting driver. In the event of strong winds and precipitation, the lifting operation is prohibited. The appropriate time for hoisting construction should be arranged to lay equipment cables and install lightning protection equipment.
Process inspection During the operation of the mixing equipment, periodic static self-inspection should be carried out, mainly to carry out a comprehensive inspection of the structural components of the mixing equipment to ensure that the installation is firm, the verticality is qualified, the protective railing is intact, the liquid level of the heat transfer oil high level tank is normal, the power and The signal cable is connected correctly.
debugging
Idling debugging
The process of idling debugging is as follows: test the motor → adjust the phase sequence → no-load operation → measure the current and speed → observe the operating parameters of the power distribution equipment → observe the signal returned by each sensor → observe whether the control is sensitive and effective → observe the vibration and noise If there is any abnormality during idling debugging, it should be eliminated.
During idling commissioning, the sealing condition of the compressed air pipeline, the pressure value and movement of each cylinder should be checked, and the position signal of each moving part should be checked. After idling for 2h, check whether the temperature of each bearing and reducer is normal, and calibrate each load cell. After the above debugging is normal, you can purchase fuel and start debugging the thermal oil boiler.
Commissioning of thermal oil boilers
Dehydration of the thermal oil is a key task. The thermal oil must be dehydrated at 105 ℃ until the pressure is stable, and then heated to 160-180 ℃, and the oil can be replenished and exhausted at any time to achieve stable inlet and outlet pressure and stable liquid level . When the temperature of the thermal insulation pipes of each asphalt tank reaches the normal working temperature, raw materials such as asphalt, crushed stone, ore powder can be purchased and ready for commissioning.
Feeding debugging
The debugging of the burner is the key to the debugging of the feeding. Taking the heavy oil burner as an example, qualified heavy oil should be purchased according to its instruction manual. The method of rapid detection of heavy oil on site is to add diesel oil, and the high-quality heavy oil can be dissolved in diesel oil. The heating temperature of heavy oil is 65 ~ 75 ℃, too high temperature will produce gas and cause fire. The correct setting of the parameters of the burner can achieve smooth ignition, the combustion flame is stable, and the temperature increases with the increase of the opening, and the cold material system can be started to charge.
Do not add stone chips with a particle size of less than 3mm for the first test machine, because if the flame is suddenly extinguished, the undryed stone chips will adhere to the roller guide plate and small mesh vibration screen, etc., which will affect the future use. After feeding, the temperature of the aggregate and the temperature of the hot silo displayed by the computer should be observed, and the hot aggregates of each hot silo should be discharged separately, and then be taken out by the loader, measure the temperature and compare it with the displayed temperature. In practice, there is a difference between these several temperature values, which should be carefully summarized, repeatedly measured, and distinguished to accumulate data for future production. When measuring temperature, use infrared thermometer and mercury thermometer for comparison and calibration.
Send the hot aggregates from each bunker to the laboratory for screening to check whether it meets the corresponding range of the sieve hole. If there is mixing or tandem phenomenon, the cause should be investigated and eliminated. Observe and record the current of each part, the speed of reducer and bearing. In the waiting state, observe and adjust the position of the two thrust wheels of the flat tape, oblique tape, and roller, and observe that the operation of the roller should be free of impact and no abnormal noise. Analyze the above inspection and observation data to confirm whether the drying and dedusting system is normal, whether the current and temperature of each part are normal, whether the operation of each cylinder is normal, and whether the time parameters set by the control system are applicable.
In addition, during the feeding and debugging process, the position of the hot material bin door, aggregate weighing door, mixing cylinder door, finished product cover, finished product door, and trolley door should be correct and the movement should be smooth.
Trial production
After the commissioning of the materials is completed, you can communicate with the construction technicians to carry out trial production and pave the test section. The trial production shall be carried out according to the mixing ratio provided by the laboratory. The trial production must be after the measured temperature of the hot aggregate reaches the requirements before it can be transferred to the mixing state. Taking AH-70 asphalt limestone mixture as an example, its aggregate temperature should reach 170 ~ 185 ℃, and the heating temperature of asphalt is 155 ~ 165 ℃.
Arrange a special person (tester) to observe the appearance of the asphalt mixture in a safe position on the side of the transport vehicle. The asphalt should be coated evenly, without white granules, without obvious segregation and agglomeration. In fact, the measurement temperature should be 145 ~ 165 ℃, and do Good appearance and temperature record. Sampling is used for extraction test to check the gradation and oil-rock ratio to check whether the control of the equipment is accurate.
Attention should be paid to the test error, and a comprehensive evaluation should be carried out in combination with the actual effect after paving and rolling. It is impossible to draw conclusions about whether the equipment control is accurate in a trial production. When the cumulative output of the mixed materials of the same specification reaches 2000t and 5000t, the computer statistical data, the actual consumption of materials, the number of finished 名媛直播 and test data should be analyzed together To reach a conclusion. Asphalt measurement accuracy of large-scale asphalt mixing equipment should reach ± 0.25%. If this range is not reached, the cause should be found and resolved.
Trial production is a stage of repeated commissioning, summary and improvement. It requires a large amount of work and high technical requirements. It requires close cooperation of various departments and requires management technicians to have some experience. The author believes that the trial production can only be completed after commissioning to ensure stable and reliable operation of all parts of the equipment, normal parameters, and stable and controllable mixture quality.
Staffing
Large-scale asphalt mixing equipment should be equipped with one manager with engineering machinery management and work experience, two operators with high school education or above, and three electricians and mechanics. According to our practical experience, the division of work types should not be too fine, and should be specialized and versatile. Operators should also participate in maintenance and repair, and they can replace each other during work. It is necessary to select personnel who can endure hardship and love to study and manage to improve the overall ability and work efficiency of the entire team.
acceptance
The management personnel of large-scale asphalt mixing equipment should organize manufacturers and construction technicians to summarize the commissioning process, test and evaluate the quality of the trial production mixture, equipment handling performance, and safety protection facilities, and compare it with the requirements of the purchase contract and specification to form a written form. Acceptance information.
Installation and commissioning are the basis for safe and efficient operation of equipment. Equipment management personnel should have clear ideas, focus on innovation, and make overall arrangements, strictly abide by safety technical regulations and schedule plans to ensure that equipment is put into production and runs smoothly as scheduled, which is a strong guarantee for road construction.
