Concrete delivery pump is composed of pump body and delivery pipe, which is mainly used in house construction, bridge and tunnel construction. However, some common faults will inevitably be encountered in daily operations. How can we prevent them?
1. Common failures of concrete delivery pumps
Easy to block the pump location and elimination method
Blocking at the outlet of the distribution valve
The discharge port is blocked, usually the pumping system action is suddenly interrupted, and there is abnormal sound, the equipment has strong vibration, but there is no corresponding vibration in the pipeline.
Remedy: Pour the cement slurry into the hopper, and start the pump repeatedly in forward and reverse directions to force the passage to open. If this method is not daring, it can only be eliminated manually, remove the connected pipe, and remove the debris in the valve.
Blockage at the inlet
The feed inlet is blocked, usually the pumping action and the hydraulic system are normal, there is no abnormal sound and vibration, there is large aggregate or agglomeration in the hopper, which is stuck or arched at the feed inlet.
Remedy: run the pump in reverse to destroy the agglomeration, return the concrete to the hopper and mix again, then pump forward. If it doesn't work, it needs to be cleaned manually and eliminated.
Blockage of concrete pipeline
When the conveying pressure gradually increases, and the hopper level does not decrease, the pipe outlet does not discharge, the pump vibrates, and the pipeline is also accompanied by strong vibration and displacement, it can be determined that the pipeline is blocked.
Judgment of the clogged part: The clogging generally occurs in the elbows, cones, and vibrating areas. At this time, you can use a small hammer to hit along the pipeline, the dull sound is the blockage; the clear sound is normal. Listening with ears, a rustling sound is normal, and a harsh sound is a blockage.
Blocked at the pipe valve
The blockage at the pipe valve is gradually formed. The main reason is that after the concrete is pumped, it is not washed with high-pressure water in time, causing the concrete to remain in the pipe, which gradually thickens over time and builds up and solidifies, causing blockage.
Remedy: After pumping concrete, be sure to rinse the pump body and S pipe with high-pressure water. When flushing is ineffective, brazing can be used to remove the residue until it is completely clean.
Exclusion method: When the pipe blockage occurs, the method of repeating the positive and reverse pumps should be taken immediately, and the concrete at the pump outlet is gradually sucked back into the hopper and mixed again before delivery. The method of knocking with a wooden hammer, combined with positive and reverse pumps, can also be used to clear it; when the above method is invalid, it means that the blockage is serious. After identifying the clogged section, remove the pipe and wash it with high-pressure air blow or heavy hammer or high-pressure water. After thoroughly cleaning up, connect the pipeline and continue pumping concrete.
2. Preventive measures for concrete delivery pumps
1) When installing and designing pipes, avoid 90 as much as possible. And S-bend.
Try not to use pump tubes with obvious pits to reduce the resistance of pumping concrete and prevent clogging. The pump tube should be checked frequently. If the pump tube is worn to a large extent in one direction, the tube should be replaced in time. If the thickness of the pump tube is too thin, a new tube should be replaced in time to prevent the pump tube from exploding or the pump being replaced during the process Tube blocking caused by long tube time.
(2) In order to ensure the continuity of pumping concrete operation and the quality of concrete pouring, the interval between operations should not be too long to prevent clogging.
If the interval time is longer for some reason, the pump should be started every 20 minutes or the reverse and forward pumps should be started several times. If necessary, the circulating pump should be hit to prevent blockage.
(3) The pumped concrete should meet the pumpability requirements, and if necessary, determine the mix ratio of the pumped concrete by testing the pump.
First, the ratio of the maximum particle size of coarse aggregate to the diameter of the conveying pipe should be determined.
When the pumping height is less than 50m, it should not be greater than 1:3 for gravel and 1:2.5 for pebbles; when the pumping height is 50-100m, it should be in the range of 1:3 to 1:4; the pumping height is 100m Above, it should be between 1:4 ~ 1:5. The content of needle flake particles should not be greater than 10%.
