The mixing station is an indispensable important equipment in the construction industry, and its normal operation is directly related to project quality and construction progress. However, in the daily operation of the mixing station, it is inevitable to encounter various faults caused by aging and wear of components, as well as the impact of complex environments.
Today, Zhengzhong Heavy Industry will share some common faults of mixing stations and their troubleshooting methods, hoping to provide you with some help.

1. Troubleshooting of the mixing host

1. The mixing host cannot start normally
Cause analysis:
① Air compressor status or air circuit system pressure issue: If the air compressor is not turned on, or the pressure of the air circuit system is below the required 0.4Mpa for normal operation, the mixing host will not receive enough air pressure signal to start.
② Circuit breaker not connected: Check the status of circuit breakers QF1 and QF2. If these two key circuit breakers are not in a closed state, the mixing host will not start due to lack of power supply.
③ Emergency stop button not properly reset: In an emergency, the emergency stop button is pressed to immediately stop the equipment. If it is not reset to normal afterwards, the mixing host will remain in a locked state and cannot be restarted.
④ Abnormal status of the host maintenance door: If the maintenance door of the mixing host is not fully closed or the emergency stop switch (usually linked with the maintenance door) is not reset, the system will consider there is a safety hazard and automatically prevent the mixing host from starting to ensure the safety of the operators.
Fault handling:
① Turn on the air compressor
② Wait for the air supply system pressure to rise above 0.4Mpa before starting the host
③ Close circuit breakers QF1, QF2 
④ Reset the emergency stop button
⑤ Ensure the maintenance door of the host is closed or reset the emergency stop switch

2. Mixing host stalls
Cause analysis:
① The waiting hopper door is not closed tightly, causing aggregates to leak into the mixer and overload.
② Low air pressure or leaking discharge cylinder, causing the hopper door to be pushed open and aggregates to discharge into the host.
③ The powder butterfly valve is not closed tightly, causing powder to leak into the mixer.
④ Foreign objects in the mixer, jamming the mixing arms.
⑤ Residual material in the waiting hopper discharges into the mixer after shutdown.
⑥ Sudden power failure.
Fault handling:
① Regularly clean the accumulated material on the waiting hopper door to ensure it closes tightly.
② During production, ensure the air compressor operates normally; check that the air supply pipeline has no leaks; check the hopper valve cylinder, and replace it if it leaks.
③ Remove the soft connection at the butterfly valve outlet and check if the butterfly valve plate is closed tightly. If there is a gap, adjust the valve plate to the closed position.
④ Check the interior of the mixer for foreign objects; regularly clean the concrete clumps on the mixing arms to ensure they operate well.
⑤ Before shutting down after production, ensure that the residual material in the waiting hopper is completely discharged to ensure the hopper is empty.
⑥ Use the manual switch to open the discharge door of the hydraulic opening, try to empty the material in the cylinder, and clean it manually.

3. Vibration and abnormal noise of the mixing host
Cause analysis:
① Liner contacting the mixing arm.
② Abnormal noise and vibration of the reducer.
③ Loose V-belt.
④ Abnormal noise and vibration of the motor.
⑤ Bearing damage.
Fault handling:
① Timely adjust the position of the mixing arm.
② Check if the protective cover is loose.
③ If there are abnormalities in the reducer and motor, check if there are issues with the bearings. If damaged, replace the bearings, gears, and lubricating oil.
④ Adjust the belt tension.

4. Uneven mixing and poor quality
Cause analysis:
① Wear of the mixing arm: As the core component of the mixing host, wear of the mixing arm directly affects mixing efficiency and effect, leading to uneven mixing.
② Mixing time too short: If the mixing time is set too short, the components in the concrete cannot be fully mixed evenly, thus affecting the quality of the concrete.
③ Improper timing of aggregate and cement input: The order and timing of adding aggregates and cement have a significant impact on the mixing effect. If the timing is inappropriate, it may lead to some materials not being fully mixed, thereby affecting the overall quality of the concrete.
④ Concrete solidification in the mixing cylinder: If there is concrete residue in the mixing cylinder that has solidified, it will occupy mixing space and affect the mixing effect of the newly mixed concrete.
Fault handling:
① Replace the mixing arm: Replace severely worn mixing arms to ensure their integrity, improving mixing efficiency and uniformity.
② Adjust mixing time: Set the mixing time within a reasonable range, recommended to be 30 to 40 seconds, to ensure that the components in the concrete can be fully mixed evenly.
③ Optimize input timing: In principle, 80% of the aggregates should be added first, followed by slow addition of cement, avoiding pushing the cement towards the edge of the mixing cylinder, ensuring they mix at the optimal time for the best mixing effect.
④ Clean the solidified concrete in the mixing tank: Regularly clean the residual concrete in the mixing tank to prevent it from solidifying and affecting the mixing effect.

II. Troubleshooting of the screw conveyor
1. Insufficient delivery of powder tank
Cause analysis:
① Powder arching, blockage at the discharge port, small opening of the discharge butterfly valve, insufficient material in the powder tank, etc., lead to poor powder discharge.
② Deformation of the screw blade, unable to transport normally.
Fault handling:
① Open the arch breaking device of the powder bin.
② Check for blockages at the powder bin outlet and clean them in a timely manner.
③ Check the opening angle of the powder bin discharge butterfly valve and open it to a reasonable position to ensure smooth discharge.
④ Check if the blades of the screw conveyor are deformed; if deformed, they need to be removed, corrected, or replaced.

2. Noise or abnormal sound from the screw pipe.
Cause analysis:
① The screw core shaft (blade) scrapes against the inner wall of the pipe.
② The central suspension shaft is broken.
Fault handling:
① Detect and adjust the concentricity of the core shaft.
② If the central suspension shaft is broken, it needs to be replaced in a timely manner.

3. Dust leakage phenomenon.
Cause analysis:
① Gearbox dust leakage: The shaft end sealing gasket is damaged.
② Observation window dust leakage: Not tightened.
③ Universal joint dust leakage: At the connection of the universal joint.
Fault handling:
① Replace the sealing gasket of the gearbox.
② Tighten the observation window support rod screws; apply a layer of glass glue on the sealing rubber sheet.
③ Weld or apply a layer of glass glue at the connection of the universal joint.

III. Troubleshooting of the belt conveyor
1. The inclined belt cannot start.
Cause analysis:
① The stop button of the inclined belt machine is not connected.
② Check if the emergency stop button of the belt is closed.
Fault handling:
① Check if the maintenance stop button is connected.
② Check if the belt tension stop switch is connected (at both ends of the belt).

2. The belt is misaligned.
Cause analysis:
① Roller contamination: The surface of the roller is adhered with mud, sand, or other impurities, causing the contact surface between the roller and the belt to be uneven, which leads to the belt deviating from its intended path during operation.
② Insufficient counterweight or slack belt: Improper counterweight setting of the belt conveyor, too light, or the belt itself becoming too loose due to long-term use, will cause the belt to be unable to maintain stable tension during transportation, easily leading to misalignment.
③ Material drop point deviation: The drop point is not at the center of the belt; an asymmetric load distribution will cause lateral forces to act on the belt during operation, leading to misalignment.
④ Uneven elongation of the belt: Over a long period of use, the belt may experience uneven tension, excessive stretching, or local wear, leading to differences in length at different positions; this uneven elongation makes it difficult for the belt to maintain linear motion during operation, causing misalignment.
Fault handling:
① Clean the rollers: Regularly remove mud, sand, and impurities from the surface of the rollers to ensure they are clean and smooth.
② Adjust the belt tension: Tighten the belt by increasing the counterweight or adjusting the screw rod to ensure the belt has appropriate tension during operation.
③ Optimize material placement: Take measures to adjust the material placement position to ensure that materials can accurately and evenly fall at the center of the belt.
④ Correct the position and angle of the drum and rollers: Regularly check and adjust the position and angle of the tail drum of the belt conveyor, as well as the parallelism and symmetry of the upper and lower rollers, to ensure they are in the correct working state.

3. The support roller does not rotate or has abnormal noise.
Cause analysis:
The bearings inside the support roller are damaged, leading to inability to rotate smoothly and generating unnecessary friction noise.
Fault handling:
The damaged support roller bearings need to be replaced, and the support roller should be reinstalled in its original position to ensure the restoration of its normal rotation function and eliminate abnormal noise.

IV. Troubleshooting of the admixture pump
1. Slow pump liquid speed.
Cause analysis:
① Incorrect motor direction: The rotation direction of the motor does not match the design direction of the pump, which will reduce the working efficiency of the pump.
② Liquid level too low: If the liquid level in the admixture tank is below the pump's suction inlet, it will prevent the pump from fully drawing in liquid.
③ Inlet pipe blockage: If impurities accumulate in the inlet pipe, it will hinder the smooth flow of liquid, causing resistance during the pump's transportation process, resulting in a decrease in speed.
Fault handling:
① Adjust the motor wiring polarity: Check and confirm the rotation direction of the motor; if it does not match the design direction of the pump, the wiring polarity of the motor needs to be adjusted to ensure the correct rotation direction.
② Supplement the admixture: Check the liquid level height in the admixture tank; if the liquid level is too low, it should be supplemented in a timely manner.
③ Clean the filter screen at the outlet of the admixture tank; appropriately close the ball valve at the outlet end of the admixture pump.

2. Admixture pump leaks.
Cause analysis:
① Mechanical seal damage: Due to improper operations such as dry grinding, the sealing ring of the mechanical seal may be burned due to high temperatures, losing its original sealing performance, leading to leakage.
② Improper maintenance during shutdown: If the admixture pump at the mixing station is not properly maintained after a long shutdown, it may lead to liquid residue drying and hardening on the contact surface of the mechanical seal, affecting the sealing effect and causing leakage.
Fault handling:
① Replace mechanical seals: In cases where the sealing ring is burned due to dry grinding and leaking, the entire mechanical seal assembly should be replaced in a timely manner to ensure that the new sealing components have good sealing performance and durability.
② Clean mechanical seals: Contact the pump manufacturer for professional cleaning and maintenance guidance. Following the manufacturer's advice, thoroughly clean the mechanical seals to remove any residual dried liquid and impurities.

Others
1. The weighing hopper does not receive material.
Cause analysis:
① The flat belt motor is not turned on: If the flat belt motor is not in operation, it will not be able to transport materials into the weighing hopper.
② Abnormal state of the weighing hopper door: If the discharge door of the weighing hopper is not completely closed, or if its limit switch is damaged and the signal is not correctly fed back to the control system, it will also prevent the weighing hopper from receiving materials correctly.
③ Weighing instrument failure: The weighing instrument is a key component controlling the material feeding. If it is not functioning properly, such as the indicator light not being on or internal program errors, it will directly affect the feeding function of the weighing hopper.
Fault handling
① First, check and ensure that the flat belt motor is turned on and in normal working condition. If it is not turned on, it should be started immediately to see if feeding resumes.
② Confirm whether the discharge door of the weighing hopper is completely closed. Check the magnetic induction switch associated with the discharge door and observe whether its indicator light is on to determine if the switch is functioning normally.
③ Check whether the feeding indicator light of the weighing instrument is on to determine if the instrument is in a normal working and receiving command state. If the indicator light is off or the instrument shows abnormalities, further check the power supply, connection lines, and internal settings of the instrument, and restart or seek professional repair if necessary.

2. No discharge after aggregate weighing.
Cause analysis:
① The valve of the waiting hopper has not completely closed, possibly due to material jamming or improper operation.
② The weighing instrument has malfunctioned and failed to issue a normal discharge signal, affecting the discharge process.
③ The precision door of the aggregate scale is not closed properly, hindering the discharge operation.
④ The weighing sensor terminal of the aggregate measuring hopper is damaged.
⑤ The belt conveyor is not running.
⑥ The discharge sequence of the aggregate is not defined.
Fault elimination:
① Check the valve of the waiting hopper: First, confirm whether the valve of the waiting hopper is completely closed, and check if there is any material jamming the valve or if the valve itself is not properly closed. If a problem is found, clear the jam or readjust the valve position to a fully closed state.
② Check the weighing instrument: Enter the control system, check the working status of the weighing instrument, and confirm whether it is operating normally and issuing the correct discharge signal. If a fault or abnormal signal is found, troubleshoot according to the operation manual or contact professional maintenance personnel for handling.
③ Verify the closing status of the precision door: Check whether the precision door of the aggregate scale is correctly closed and locked. If it is not closed properly, manual adjustment or repair of the closing mechanism is required to ensure that the precision door can close completely and seal.
④ If the weighing sensor terminal is damaged, replace the damaged parts as needed.
⑤ Check whether the belt conveyor is started.
⑥ Check the computer interface and set the discharge sequence of the aggregate.

3. Dust from the top of the tank during powder material transportation.
Cause analysis:
① The filter element of the dust collector is clogged, causing "pressure build-up," leading to the safety valve at the top of the tank opening and producing dust.
② If the material level gauge fails, and feeding continues after the powder material is full, dust will appear at the top of the tank.
Fault elimination:
① Conduct a comprehensive inspection of the filter element condition of the top dust collector and carry out necessary cleaning work.
② If dust is found, immediate action should be taken to thoroughly clean the accumulation of powder around the safety valve to prevent rainwater from causing the powder to clump and block the normal function of the safety valve.
③ If the dust phenomenon is caused by excessive loading of powder material, immediately check and verify the accuracy and reliability of the material level gauge and full alarm device.

The above is the troubleshooting and solutions for common faults in the mixing station shared this time.
We understand that the stable operation of equipment is a solid support for the smooth progress of your project. Zenxon Heavy Industry is always by your side, committed to providing efficient and reliable equipment solutions.
If you have any questions or need product and technical support, please feel free to call the service hotline: 400-186-0868. Zenxon Heavy Industry is on standby 24 hours a day, with a professional technical team to ensure the safety of your mixing station.