Concrete pump delivery cylinder blockage is a common fault in concrete delivery equipment operations. How to deal with it so as not to affect the construction progress and avoid irreversible damage to the equipment?
Preliminary Preparations
- Equipment Shutdown and Power Off: Stop the concrete pump and close the concrete hopper’s feed valve to prevent new concrete from entering the concrete pump delivery cylinder and exacerbating the blockage.
- Safety Equipment: Operators must wear full safety gear and, if the site is dusty, a dust mask.
- Tools and Materials: Prepare specialized tools in advance, such as a high-pressure water gun (pressure no less than 30 MPa) and a steel pipe unclogging system. Also, prepare clean water, lubricant, and a receiving bucket.
Determining the Blockage Location
- Check the pressure: If the hydraulic pressure gauge suddenly spikes to the maximum but the concrete pump delivery cylinder remains stationary, the blockage is inside the concrete pump delivery cylinder. If the pressure slowly rises and the concrete pump delivery cylinder moves slightly but no concrete is released, the blockage is at the inlet and outlet connections.
- Listen to the sound: A regular “thumping” sound is normal. If it becomes dull, stuck, or has a strange “sizzling” sound, the blockage is in the section of the concrete pump delivery cylinder with the unusual sound.
Targeted Solutions for Blockage Problems
- Partial blockage inside the concrete pump delivery cylinder
Reverse Conveying: Turn on the equipment’s “Reverse Conveying” switch, move the piston backward, and push the obstruction back into the hopper. If residue flows back, the obstruction has been loosened.
High-Pressure Water Jet Flushing: Turn off reverse conveying, remove the connecting flanges at the feed or discharge port of the concrete pump delivery cylinder, and flush with high-pressure water until clear water flows.
Lubrication and Test Run: Apply lubricant to the inner wall of the concrete pump delivery cylinder and the piston surface, reinstall the flanges, and start the equipment in a “dry run” (without adding concrete to the hopper) to observe whether it operates smoothly. Then add a small amount of concrete for a test run. If all is well, resume operation.
- Entire blockage inside the concrete pump delivery cylinder
Loosening the Blockage: Disassemble the concrete pump delivery cylinder and remove it completely. Use a steel chisel to gently tap the edges of the blockage to gradually loosen the accumulated concrete. If the blockage is firm, apply a “concrete dissolver” to the blockage and let it sit for 30-60 minutes.
Cleaning and Inspection: Remove all loosened blockages and flush the interior of the concrete pump delivery cylinder with a high-pressure water jet. After rinsing, wipe the concrete pump delivery cylinder walls with a cotton cloth and inspect for scratches.
Reassembly and Commissioning: Reinstall the concrete pump delivery cylinder back into the frame. Connect the lines. Start the machine and test the hydraulic system pressure. Observe the reciprocating speed of the delivery cylinder to ensure it is normal (. Once confirmed, conduct a trial delivery of concrete.
Preventive measures
- Concrete Quality Control: Ensure the maximum gravel particle size does not exceed 1/3 of the cylinder’s inner diameter, and ensure the slump meets equipment requirements. Avoid using segregated or initially set concrete.
- Daily Equipment Maintenance: Inspect the inner wall of the delivery cylinder for wear before daily operation; replace the piston seal weekly; after operation, flush the delivery cylinder, hopper, and pipelines with a high-pressure water jet .
- Operational Specifications: Operators must receive professional training. Avoid frequent starting and stopping of the equipment during operation. After a pause of more than 30 minutes, reciprocate the cylinder every 10 minutes to prevent the concrete from setting.
To sum up, the blockage of the concrete pump delivery cylinder will not only delay the construction progress, but also affect the quality of the project. Therefore, taking the above measures to deal with it in time can not only effectively avoid the above problems, but also ensure the smooth progress of the project construction.
