Preventive Maintenance Checklist For Concrete Batching Plant

The preventive maintenance checklist for concrete batching plant is organized by daily, weekly, monthly, quarterly and annual maintenance cycles, covering the maintenance points of key equipment and systems to help ensure efficient operation of the equipment and extend its service life.

I. Daily maintenance (before and after daily operations)

1. Mixing main machine system

– Inspection content:

– Clean the residual concrete in the mixing tank to prevent hardening and affect mixing efficiency.

– Observe the wear of the mixing blades and linings. If there is an obvious gap or thickness reduction, record it in time.

– Check whether the sealing parts of the main machine (such as the shaft end seal) are leaking, and add sealing grease (if there is an automatic lubrication system, confirm that it is operating normally).

– Check whether the main machine motor and reducer have abnormal noise or overheating during operation.

2. Batching system

– Inspection content:

– Whether the material level of each silo (sand, cement, fly ash, etc.) is normal, and remove debris from the silo feed port.

– Whether the belt conveyor deviates during operation, whether the belt surface is damaged, and whether the tensioning device is firm.

– Check whether the sensor connection of the weighing bucket (aggregate, powder, water and additive) is loose, and whether the seal of the weighing bucket door is tight.

3. Conveying system

– Inspection content:

– Whether the screw conveyor (powder conveying) is stuck during operation, and whether the gap between the spiral blade and the shell is uniform.

– Whether the chain tension of the bucket elevator (if any) is appropriate, and whether the bucket is deformed or detached.

– Whether the belt conveyor roller rotates flexibly, and remove the material adhering to the roller.

4. Control system and safety device

– Inspection content:

– Whether the indicator lights and buttons of the operation panel are normal, and whether the display screen is clear.

– Function test of the emergency stop button and overload protection device to ensure that the machine can be stopped immediately in an emergency.

– Whether the door locks of each electrical cabinet are closed to prevent dust from entering and affecting the performance of components.

II. Weekly maintenance (after every 50-60 hours of operation)

1. Lubrication system

– Maintenance items:

– Manually add grease to each lubrication point (such as the shaft end of the mixer, belt conveyor bearing, cylinder pin, etc.), refer to the lubrication chart marked in the equipment manual.

– Check the oil level of the automatic lubrication pump. If it is lower than the minimum scale line, add special grease, and confirm whether the pump body is supplying oil normally during operation.

2. Batching and weighing system

– Maintenance items:

– Calibrate the accuracy of the aggregate and powder weighing bucket (using standard weights or materials of known weight), and the error must be controlled within ±1%.

– Clean the dust on the surface of the weighing sensor and check whether the sensor cable is worn or has poor contact.

3. Pneumatic system

– Maintenance items:

– Drain the air tank of the air compressor and check whether the compressed air pressure is stable (usually 0.6-0.8MPa).

– Clean or replace the filter element of the pneumatic triplex (filter, pressure reducing valve, oil mist collector), and add lubricating oil to the oil mist collector oil level.

– Check whether the cylinder, solenoid valve and air pipe are leaking, and whether the joints are loose.

4. In-depth inspection of the mixing host

– Maintenance items:

– Open the host inspection door and check the gap between the mixing arm and the liner (normal gap ≤5mm, if exceeded, it needs to be adjusted or replaced).

– Tighten the internal bolts of the host (especially the fixing bolts of the mixing arm and liner) to prevent loosening and falling off.

III. Monthly maintenance (after every 200-300 hours of operation)

1. Electrical system

– Maintenance items:

– Check whether the wiring terminals of the components (contactors, relays, circuit breakers) in each electrical cabinet are loose, and clean the internal dust.

– Test the insulation resistance of the motor (using a megohmmeter), the insulation value should be ≥0.5MΩ, otherwise it needs to be dried or repaired.

– Calibrate temperature and pressure sensors (such as hydraulic system pressure gauges, host temperature sensors).

2. Hydraulic system (if any)

– Maintenance items:

– Check the oil level and oil quality of the hydraulic oil tank. If the oil becomes turbid or emulsified, replace the hydraulic oil (reference oil model: L-HM 46 anti-wear hydraulic oil).

– Clean the hydraulic oil filter element, check whether the cylinder and oil pipe joints are leaking, and whether the piston rod surface is scratched.

3. Belt conveyor

– Maintenance items:

– Adjust the belt tension to ensure that there is no slipping during operation; replace the belt with severe wear (such as surface cracks and delamination).

– Check the bearing clearance of the belt conveyor drive roller and redirection roller, and add high-temperature grease (NLGI grade 2).

4. Dust removal system

– Maintenance items:

– Clean the dust on the surface of the bag dust collector (or filter cartridge), check whether the bag is damaged, and replace it if necessary.

– Test the operating efficiency of the dust collector fan to ensure the dust removal effect (emission concentration ≤30mg/m³).

IV. Quarterly maintenance (every quarter or after 600-800 hours of operation)

1. Wear detection of key components

– Inspection items:

– Use a vernier caliper to measure the remaining thickness of the mixing blade and liner (replace when the wear exceeds 1/3 of the original thickness).

– Check the wear of the screw conveyor blades. Replace when the blade edge thickness is ≤5mm.

– Wear detection of the weighing bucket liner (if any) to ensure that the weighing accuracy is not affected.

2. Control system function test

– Test items:

– Simulate the batching process of each material to verify whether the logic of the automatic control system (PLC) is correct and whether the batching error is within the allowable range.

– Back up the control system program to prevent program loss or damage.

3. Safety and environmental protection facilities

– Maintenance items:

– Check whether the fire extinguisher pressure is normal (the pointer is in the green area) and replace expired fire extinguishers.

– Clean up the debris in the drainage ditch on the site to ensure smooth drainage; check whether the wastewater recovery system (if any) is operating normally.

V. Annual maintenance (every year or after 2000-3000 hours of operation)

1. Systematic overhaul

– Overhaul items:

– Disassemble the main mixer, thoroughly clean the internal material accumulation, and replace all worn blades, liners and seals.

– Disassemble the reducer, check the gear wear, and replace the gear oil (GL-5 85W/90 heavy-duty gear oil is recommended).

– Replace all conveyor belts, screw conveyor blades and other wearing parts.

2. Electrical and instrument calibration

– Calibration items:

– Entrust a professional organization to calibrate the weighing system, sensors and instruments (such as pressure gauges, thermometers), and issue a calibration report.

– Check the aging of the cable insulation layer and replace aged or damaged cables.

3. Machine performance test

– Test items:

– Conduct a full-load mixing test to detect the mixing time and concrete homogeneity (slump deviation ≤±20mm).

– Test whether the whole machine noise (factory boundary noise ≤85dB) and energy consumption (power consumption per cubic meter of concrete ≤1.2kWh) meet the standards.

VI. Special maintenance (seasonal or before long-term shutdown)

1. Winter antifreeze maintenance

– Maintenance measures:

– Empty the residual water in the water pump, water pipe, and weighing bucket to prevent freezing and cracking; add antifreeze (ethylene glycol) to the water circulation system.

– Replace the hydraulic oil and lubricating oil with low-temperature models (such as L-HV 32 hydraulic oil in winter) to ensure smooth low-temperature start of the equipment.

2. Long-term shutdown maintenance

Maintenance measures:

– Empty all silos and materials in the weighing bucket, and thoroughly clean the mixing tank, belt conveyor and conveying pipeline.

– Cover the motor, reducer and other equipment with dust covers, and apply anti-rust oil to the exposed metal parts.

– Start the equipment to run idle for 10-15 minutes every half month to prevent the bearings from rusting or the electrical components from getting damp.

Maintenance records and management

– Record requirements:

– Establish a “Maintenance Ledger” to record maintenance time, items, replacement parts models and operators in detail.

– Establish replacement cycle statistics for wearing parts (such as blades, liners, belts), and prepare in advance to reduce downtime.

– Regularly analyze maintenance data, identify high-frequency equipment failure points, and optimize maintenance plans.

Notes: Maintenance operations require power off and “under maintenance” warning signs must be hung. Safety belts must be worn when working at heights. When hydraulic and pneumatic systems are involved, pressure must be released first to ensure safe operation. It is recommended to adjust the maintenance cycle and content in combination with the equipment manufacturer’s instructions and actual operating conditions.