From startup to shutdown, every process needs to be understood in order to run an asphalt mixing plant efficiently. This guide presents you with the best practices of safety, production and maintenance which will result in an efficient operation of your bitumen mixing plant. By adhering to these principles, you can streamline production, reduce operational costs, and confidently tackle any challenge that comes your way.
A good inspection is vital for safety and readiness before you even think about turning on the plant.
Safety First: Add a warning sign to the equipment space to make sure it is not used by unauthorized personnel. Ensure that all safety equipment such as fire extinguishers and gas leak alarms are in proper working order. For gas pipelines, you can use a handheld detector to check for any leaks.
Lubrication Management: Fill Clearance: The filling cycle of each bearing point should be clearly defined in the grease filling record sheet. Mixer bearings, etc., which are hot, must be lubricated with high-temperature grease.
Material and Component Inspections: Check the moisture content of the stone to avoid heating problems. Check and tighten all loose parts, particularly on moving parts, to operating specifications.
The start-up sequence is strictly logical and has safety built in.
Before the main circuit breaker is closed, the phase-to-phase voltage should be monitored; it should be within the range of 380 +- 5% V An alarm will be sounded in three 2 second bursts at over 85dB. Sequence of powering on of equipment: Main control – PLC cabinet – Operation console. The system has emergency stop alarm and observation alarm and the emergency stop alarm is prioritized.
Equipment Logic: The equipment must be started in a certain interlocked order. For example, the air compressor needs to be in operation when the pressure is greater than 0.7 MPa before the asphalt circulating pump can be started. There must be a minimum interval of over 15 seconds between the start-up of each device to avoid transient current surges. In case, if any link in the series breaks down, it will automatically trip and the alarm will be generated.
Once the plant is in operation, it is important to keep a close eye on its operation to ensure a smooth production process.
Look, Smell, Ask, and Feel: This is a memory aid for operators to quickly figure out if something is wrong.
Look: Check for oil leaks; monitor the colour of the drum flame; blue is ideal, yellow means incomplete combustion
Smell: An unusual burning odor can indicate a slipping belt or circuit over-heating.
Ask: Operator(s) document and relay any abnormal conditions when transferring shifts.
Feel: Touch the motor housing. If it is above 60 degrees, shut the machine down for inspection.
For natural gas ignition, a purge cycle of 30 seconds or more must be performed before ignition in order to avoid explosions.
The asphalt mixing plant needs to ensure that the deviation of the aggregate temperature is less than +-10degC.
Asphalt scale needs to be zero-calibrated daily to within 0.1%.
Shut down and maintenance procedures are a necessity for equipment longevity and safety.
Hot Shutdown Procedure: Kill aggregate feed, extinguish burner, empty mixing pot and hot bin. Continue to operate the induced draft fan until the drum temperature is below 60. This helps to ensure that exhaust gas is completely expelled before the machine is de-energized.
Maintenance Best Practices: After washing and cleaning the mixing pot, spray with waste oil to prevent any rusting. In addition, the breather valve of the mineral powder tank should be cleaned to avoid caking and clogging.
Safety Warning: No live maintenance is allowed and you must follow a Lockout/Tagout (LOTO) procedure. Never go into the drum when it is still hot. Most accidents occur during repair or maintenance because parts that are not being repaired could move suddenly.
Having a trained team is extremely important to maintain any situation.
For all operations to be confirmed by two persons: an operator and an on-duty engineer. A written shift handover is required between shifts detailing equipment status and outstanding alarms for review during handover on site
Faults that are common have specific procedures for handling them. If the aggregate temperature is out of the norm, immediately check the gas pressure. If there is a gas leak, shut off the main valve at once, evacuate staff and do not use any electrical equipment. Process Drills including simulated chain failures should be held on a monthly basis.
It’s important to note that, despite this guide being dedicated to the bitumen mixing plant, the end product of the plant is critical for road construction vehicles such as pavers and rollers. The quality of the hot mix asphalt directly affects paving operations. The paving temperature should be adjusted in a timely manner, the paving crew should communicate with the operator by intercom at any time. This cooperation ensures that the quality of the final road surface is up to standards.
For individuals seeking a trusted supply of hot mix asphalt plant near me, it is essential to find a supplier that offers not only quality equipment but also comprehensive after-sales assistance and expertise. The information provided here applies to many different brands of asphalt plants, so as long as you can determine which system you’re dealing with, an operator can maximize efficiency and minimize costs regardless of who produced the equipment.
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