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In order to ensure the normal operation of the mixing plant, extend the service life of the equipment, and ensure safety and efficiency, the safety production operation details of the mixing plant have been specially made.

1. Pre shift inspection

1.1 Before starting each shift, the operator should check the oil level of the reducer of the mixing host, the oil level of the oil pressure pump of the discharge gate, the oil level of the mixing shaft head (should be more than 1/2), whether the lubricating oil level is sufficient, whether the pressure is normal, whether there are any fractures or detachment of the oil pipes and joints, and the lubrication points of the belt conveyor, screw conveyor and other parts, and add lubricating grease.

1.2 Check whether there are any metal objects inside the mixer, and whether the fixing bolts of the blades, lining plates, etc. are loose.

1.3 Close the main power supply → Close the control power switch → Close the purification power switch → Close the PLC power switch. Close the industrial control power switch → start the monitoring program and check if there are any abnormalities in the monitoring indicator lights of the monitoring box (oil level, oil temperature, and working status of the lubrication sleeve motor).

1.4 Start the mixing machine with no load and run the belt conveyor for 10 minutes. Check if the operation is normal, if there is no abnormal noise, and if the conveyor belt is off track or broken (if any abnormalities are found, immediately notify the maintenance team for troubleshooting).

1.5 Start the air compressor and check if it is running normally. Check if there is any air leakage in the air circuit. The air circuit pressure should be maintained at 0.55~0.7Mpa, and the concrete arch pressure should be 0.02Mpa.

1.6 Check the water supply system, liquid additive system, and ensure that the pipelines are running smoothly and without leakage. The water tank and liquid additive tank have sufficient liquid volume.

1.7 Check whether the unloading doors, solenoid valves, and cylinder opening and closing are normal, and whether the travel switches and signal circuits are working properly.

Manually jog the screw conveyor to check if it is operating normally. Add lubricating grease.

1.9 It is strictly prohibited to start or stop the machine with load. In case of power outage or other accidents that cause the machine to stop, the main power should be turned off first, and the discharge door of the mixer should be opened immediately. The material inside the drum should be drained and cleared to prevent condensation accidents. To restart, press "1" to restart.

The production and operation interval of the host is about 3 hours, with a maximum of 4 hours. The host must be rinsed with water once. Use a water supply pump to inject production water into the main unit, stir and rotate for about 3 minutes, release the flushing water, and continue production.

During the continuous production of C40 and above high-grade concrete, in addition to stirring and flushing with the main machine, high-pressure water guns must be used for auxiliary flushing.

1.12 The host must be shut down for at least 12 hours of production operation, with a maximum of 24 hours. Auxiliary workers must thoroughly clean the interior of the host and the material gate shaft.

1.13 Interval cleaning, flushing, and periodic cleaning should be recorded and kept for future reference.

If the belt conveyor is stopped due to standby during the production operation, it must be operated without load for 2-3 minutes before feeding production. It is strictly prohibited to start and feed at the same time to prevent damage to the conveyor belt caused by impact overload.

2. Post shift maintenance and inspection

2.1 Disconnect the main power switch, lock the distribution cabinet door (assign a dedicated person to guard), remove any debris from the inner wall of the mixer, around the mixing device, discharge door, and other directions, and check the connecting bolts of the mixing device such as the mixing impeller and lining plate.

2.2 Clean the additive measuring hopper, clean the collection hopper and powder measuring hopper discharge door.

2.3 Clean the exterior of the host and clean the lower discharge hopper of the host.

2.4 Drain the accumulated water in the air storage tank of the air compressor (in winter, drain the air compressor and the gas inside the tank).

2.5 Start the powder bin dust collector and shake off the powder adhered to the filter.

2.6 In winter, the liquid in the water pipes and additive pipelines must be drained completely.

2.7 Add lubricating grease to each lubrication point.

2.8 After shutdown, the control system power must be turned off and the main power must be turned off.

2.9 Auxiliary workers must complete the cleaning operation inside the main engine and the material gate shaft within about 1 hour after the main engine is shut down, with a maximum of 2 hours.

2.10 Auxiliary workers should clean the host carefully and thoroughly, leaving no dead corners, especially the unloading door and shaft of the host. Prevent the mortar from solidifying and drying, which may obstruct the opening and closing of the material door and damage the material door, shaft, and bearings.

2.11 Auxiliary workers are strictly prohibited from using air picks to strike the lining plate, mixing arm, and mixing blade during cleaning operations to prevent damage to the lining plate, mixing arm, and mixing blade due to improper operation.

2.12 When cleaning the soil and leaked materials in the machine pit, the auxiliary workers should not load too much soil and leaked materials onto the conveyor belt, not exceeding 2OOKg at a time, and transport them in batches to prevent damage to the drum motor and conveyor belt caused by overloading of the belt.

2.13 After the auxiliary worker completes the host cleaning operation, they immediately notify the mechanic to inspect and accept it. If the acceptance is not qualified, it must be cleaned again and cannot be postponed.

3. Weekly inspection and maintenance (performed by maintenance personnel)

3.1 Turn off the main power and assign a dedicated person to guard, inspect and remove residual dirt from the concrete inside and outside the mixer (to be carried out by the operator).

3.2 Check whether the tightening bolts of all mixing blades and blade arms are loose, and check the gap (2mm) between the mixing blades, blades, and lining plate. If it is greater than 4mm, it must be adjusted.

3.3 Check and add, the oil level of the gearbox, discharge gate oil pump, mixing shaft head, and the oil level in the monitoring mirror should be more than 1/2. Add lubricating grease to each part.

3.4 Check the pneumatic system, compressor oil, safety valve, and pressure gauge. Discharge water from the gas water separator. The pneumatic system should have no air or oil leakage.

3.5 Check and adjust the fastening bolts and support rods of each part of the belt conveyor, whether the cleaner is working properly, and whether the belt has any snake shape or deviation phenomenon.

3.6 Check whether there is any leakage in the water and additive pipelines, and whether the motor and pump are working properly.

3.7 Check the working condition of the screw conveyor and add gear oil and lubricating grease.

3.8 Check if the solenoid valve, cylinder, and discharge door of the aggregate measuring scale are working properly, and add lubricating grease.

3.9 The mechanic should actively cooperate with the auxiliary worker to carry out the cleaning operation of the main engine.

3.10 After receiving the notice of inspection and acceptance of the cleaning operation from the auxiliary worker, the mechanic shall immediately enter the machine for inspection and acceptance, and shall not use excuses to postpone.

3.11 Inspection and acceptance should be carried out carefully, thoroughly, and without leaving any blind spots. If the acceptance is not qualified, inform the auxiliary worker or the head of the mixing station that the unqualified parts and existing problems need to be cleaned again and inspected and accepted again.

During the inspection and acceptance of 3.12, the mechanic should carefully check whether the lining plate is broken, and whether the knife and arm are damaged or loose. And sign and confirm on the record sheet for future reference.

4. Monthly inspection and maintenance items (executed by mechanics)

4.1 Check the working condition of each screw conveyor, add gear oil and lubricating grease, and observe whether the bolts at the connection parts are loose or leaking dust.

4.2 Check the belt conveyor system, adjust the tightness of the belt, check for oil leakage in the drum, and replenish lubricating oil.

4.3 Check and tighten the bolts of each part, check whether the support rod and guide wheel are running normally, whether the position of the guide groove and cleaner is correct, and whether the belt has any snake shape or deviation.

4.4 Check and maintain the air compressor, clean the air filter of the air compressor, check for leaks in the lubricating oil and air pipelines, ensure that the pressure limiting valve is working properly, and check if the discharge door switch is flexible. Add lubricating grease.

4.5 Check and maintain the water supply pump, admixture pump, and motor, and inspect the pipelines for any leakage.

4.6 Check and maintain the unloading doors, solenoid valves, cylinders, flexible opening and closing, normal operation, and whether the travel switches and signal lines are working properly.

4.7 Check and maintain the mixer.

4.7.1 Check and measure the wear degree of the lining plate (if it is greater than 3mm, it needs to be replaced).

4.7.2 Check and measure the wear degree of the mixing blade and mixing arm (if it exceeds 50% of the original size, it needs to be replaced).

4.7.3 Check if the locking screws of the unloading door shaft and bearing seat are loose.

4.7.4 Check if the motor seat locking screw is loose.

4.7.5 Check if other fastening screws are loose.

4.7.6 Check and maintain whether the valve switch of the liquid measuring scale in the collection hopper on the host is flexible and whether the sensor is working properly.

4.7.7 Check and maintain the main water supply pump, motor, cylinder, and pneumatic valve.

4.7.8 Check and add lubricating grease to various parts.

5. Safety precautions

During the maintenance of the mixing plant, the main power supply must be cut off, the distribution cabinet door must be locked, and the key must be kept by the electrician. Power interruption and transmission must be operated by electricians.

When starting the belt conveyor, mixing machine, and other electric motors, it is necessary to observe whether there are people or other debris on the motor to prevent injury or damage to the equipment during startup.

During cleaning operations, it is strictly prohibited to rinse motors, electrical switches, solenoid valves, and other electrical appliances with water to prevent electric shock and damage to electrical equipment.

During the operation of the mixer, it is strictly prohibited for anyone to stand in the discharge area.

5.5 Non operating personnel are prohibited from entering the control room, smoking, and doing anything unrelated to the operation is also prohibited. There are no operators in the operating room. Before leaving, the power must be cut off and the doors and windows must be locked.