Troubleshooting of pipe blockage of the hottest pu

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With the rapid development of highway construction, some domestic and imported pumping concrete equipment have been widely used by construction units. However, in the concrete pouring operation, due to improper use, equipment pipe plugging failures occur from time to time, which not only affects the project progress, but also directly affects the project quality

1 reasons for pipe plugging

under normal circumstances, the concrete forms a columnar fluid in the center of the pumping pipeline and flows in a suspended state. There is a layer of cement slurry on the surface of the fluid. As a lubricant, the cement slurry layer contacts the pipe wall, and there is basically no relative movement between the aggregates. When the movement of some aggregates in the coarse aggregate is blocked, the movement speed of the later aggregates will gradually slow down due to the impact, resulting in the formation of aggregates in the pipeline, the mortar supporting the coarse aggregate will be squeezed away, and the remaining gap will be filled by the small aggregate. In this way, the increase of aggregate density will cause the aggregates in this section of pipeline to expand radially along the pipeline, the cement slurry lubrication layer will be damaged, the movement resistance will increase, and the speed will slow down until the movement stops, resulting in blockage

2 judgment and elimination of pipe plugging position

2.1 blockage at the feed inlet

phenomenon: the pumping action and hydraulic system are normal without abnormal sound and vibration. There are large aggregates or lumps in the hopper, which are stuck or arched at the feed inlet

Troubleshooting: reverse the pump to destroy the caking, return the concrete to the hopper for re mixing, and then pump it forward. If it doesn't work, it needs to be cleaned manually. Lft-pp/pa is a high-strength long glass fiber material

2.2 blockage at the discharge port of distribution valve

phenomenon: the pumping system suddenly stops, and there is abnormal sound. The equipment has strong vibration, but there is no corresponding vibration in the pipeline

Troubleshooting: pour 15~30 l of cement slurry into the hopper, start the pump forward and backward repeatedly, and force the passage to open. If the astmf2913 ⑴ 1 computerized anti slide tester method is invalid, it can only be eliminated manually. Remove the connecting pipe and remove the sundries in the valve

2.3s pipe valve blockage

phenomenon: the blockage at the S pipe valve is gradually formed. The main reason is that after pumping the concrete, it is not washed with high-pressure water in time, resulting in the concrete remaining in the S pipe, which is gradually thickened over time, accumulated and consolidated, resulting in blockage

Troubleshooting: after pumping concrete, the pump body and S pipe must be washed with high-pressure water. When the flushing is invalid, drill can be used to remove the residue until it is completely clean

2.4 blockage of concrete conveying pipeline

phenomenon: when the conveying pressure increases gradually, the hopper level does not drop, the pipeline 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 blocked position: blocking usually occurs in elbow, cone pipe and sections with vibration. At this time, a small hammer can be used to knock along the pipeline, and the place with dull sound is the blocking place; It is normal when the sound is clear and crisp. Listen with your ears. A rustling sound is normal, and a screeching sound is a blockage

elimination method: in case of pipe blockage, the method of repeated forward and reverse pump shall be immediately adopted to gradually make the concrete at the pump outlet suck back to the hopper for re mixing and then transport. It can also be dredged by knocking with a wooden hammer in combination with the forward and reverse pumps; When the above measures are invalid, it indicates that the blockage is serious. To avoid corrosion in the air and water oxidation, remove the pipe after identifying the blocked section, and use high-pressure wind blowing or heavy hammer to knock or high-pressure water to wash. After it is completely cleaned, connect the pipe to continue pumping concrete

3 measures to prevent pumping concrete from blocking

(1) when installing and designing pipelines, try to avoid 90 ° and S-shaped bends to reduce the resistance of pumping concrete and prevent blocking

(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 blocking. If the interval is long for some reason, the pump should be started every 5~10 minutes or so, or the average value of the reverse and forward rotation pumps for several times to prevent blockage

(3) the mix proportion of pumped concrete shall be designed in strict accordance with the provisions of pumped concrete, and the slump shall be strictly controlled

(4) the particle size of the selected aggregate must meet the requirements, generally not greater than 1/4 of the conveying pipe diameter

(5) before pumping concrete, clean water shall be used to lubricate the pipeline. Mortar shall be sent first and then concrete to prevent blockage

(6) in hot summer, wet straw bags shall be used to cover the pipeline to prevent the rapid collapse of concrete during pumping and pipe plugging. (end)

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