How to Maintain a Bucket Elevator

Maintenance Items

1. Check the tension of the bottom tensioning device. Inspect and adjust it regularly.

2. Manually rotate the elevator to check for damaged buckets and loose bolts. Ensure the chains and pins are intact. Replace partially or entirely if buckets or chains are worn or damaged.

3. Check the oil level and vibration of the reducer. Ensure they are normal.

4. Inspect whether the drive chain of the reducer contacts the housing. Check the wear of pins and chain links.

5. Replace the elastic pins of the coupling regularly.

6. Replace the drive and driven shaft gears based on their fixation and wear condition.

Maintenance Preparation

1. Conduct hazard identification, environmental identification, and risk assessment based on equipment operation, monitoring observations, and diagnostic conclusions.

2. Clarify maintenance tasks and provide technical briefings. Ensure all maintenance personnel are familiar with the equipment structure, maintenance plan, and quality standards.

3. Prepare all necessary safety and labor protection equipment.

4. Ensure specialized tools, measuring instruments, and inspection devices are calibrated and qualified.

5. Verify the model, quantity, and quality of spare parts to ensure smooth maintenance.

6. Inspect and certify lifting equipment, tools, and ropes.

7. Before removing the bucket elevator cover, ensure the following conditions are met:
   (1) The unit is safely isolated from the system, the power is cut off, and safety measures are implemented.
   (2) Equipment maintenance and confined space work permits are obtained.

Maintenance Steps

1. Open the top cover and inspection hole at the tail of the elevator. Confirm all residual materials inside are removed.

2. Remove the coupling cover. Disconnect the coupling for realignment checks. Replace six elastic pins of the coupling. Remove the drive and driven shaft bearing box covers. Inspect the lubrication and wear of the bearings.

3. Maintain the drive unit. Check that the reducer and transmission mechanism are securely welded to the base platform and the main unit head. Ensure the reducer output shaft is parallel to the head wheel. Align the centerlines of the large and small sprockets.

4. Replace chains and buckets. Prepare four chain hoists. Run the elevator to position the chains and buckets to be replaced at the top. Then, loosen the tensioning wire rope at the tail. Adjust the tensioning screw of the tail sprocket shaft. Raise the sprocket shaft to slacken the chains. Use four chain hoists at the top to tighten the chains on both sides of the head sprocket. This will slacken the chains above the head sprocket. Remove one section of buckets and chain pins from both chains. The chains will now separate into front and rear sections.

   Start replacing the chains from the top rear section. Connect the first set of new chains (usually 10 sections as a set) to the original chains at the top rear using pins. Use the two chain hoists at the top front to pull out one set of chains and buckets from the top housing. Then, connect another set of new chains to the newly installed chains at the top rear. Continue pulling out one set from the top front. Repeat this process step by step until all chains are replaced.

   After replacement, tighten the front and rear chains at the top. Select the appropriate length. Connect the front and rear chains with pins. Secure the pins tightly with cotters. Otherwise, the pins may fall off during operation and cause serious accidents. Minimize the length error between the two chains. Do not overtighten the chains. Manually rotate the chains to ensure they move freely without significant resistance. The chain replacement is now complete.

   Next, adjust the lower counterweight tensioning device to the required tension for normal operation. Ensure the tensioning device has enough adjustment range. After adjustment, at least 50% of the total travel should remain unused. Manually rotate the drive sprocket to run the traction chain for one full cycle. Check the engagement between the chain and sprocket. Replace any poorly engaged parts.

   Then, install the buckets. Fix each bucket to the chain attachment plate with four M8X25 single-end bolts. Use split-pin bolts or double nuts to secure the bucket bolts and prevent loosening. Usually, install the buckets at the temporary manhole at the tail of the elevator. After installing each bucket, manually rotate the elevator. Then, install the next bucket. Repeat this process until all buckets are installed. Pay attention to the balance of the loose side of the chains. The buckets are T-type with induced discharge baffles. Ensure the buckets are correctly positioned during installation.

5. Replace the top sprocket. The TB-type bucket elevator is vertical. The top sprocket bears the full weight of the chains, buckets, and conveyed materials. It wears out quickly and typically lasts less than two years. Before replacement, prepare the entire set of sprocket shafts, sprockets, and bearings. Follow the chain replacement steps. After disconnecting the front and rear chains at the top, use a crane to replace the entire set. Ensure the main shaft’s parallelism to the horizontal plane is within 0.3/1000.

6. During chain replacement, inspect the high-speed end backstop of the reducer. Ensure it is intact. This prevents reverse operation of the loaded buckets during a power outage, which could cause material blockage at the bottom or damage components.

7. Check the alignment of the head and tail. Ensure the drive and driven shafts remain parallel. This prevents the chains from deviating during operation.