valve blockage at

Valve at the blockage is formed gradually, mainly due to pumping concrete finish after washing with high pressure water is not timely, resulting in concrete left in the tube, gradually thickening Over time, the accumulation of consolidation, causing blockage.
Remedy: After pumping concrete, be sure to use Asphalt Mixing Plant water to rinse pump and S tubes. When flushing is invalid, brazing can be knocked to the residue removed, until thoroughly clean.
Remedy: When plugging should be taken immediately repeated, reverse pump method, the pump outlet gradually sucked back into the hopper of the concrete mix and steel cement silo. Also used wooden hammer percussion methods, combined with the positive and reverse pump, making it clear; when the above methods fail, indicating the severity of the congestion. Identify blockage after paragraph, the tube removed, with high wind or percussion hammer or high-pressure water wash, to be thoroughly cleaned after the pipeline to continue pumping concrete followed by good work.