Locating a Blockage
Concrete pumping crews and the concrete pumper must be constantly aware of the possibility of a pump line blockage, or rock jam, and be able to remove them promptly and safely. Variations in the mix, whether too rocky, wet or dry, foreign matter in the mix (such as old concrete that has broken away from mixer fins, or unmixed clumps of concrete), and other mix anomalies are tip-offs that problems may have occurred, or may be about to occur. A rising in line resistance, as shown on the pump pressure gauge, indicates line blockage. The first suspect spot for blockage is the reducer, which connects the concrete pump to the pipeline system. A quick build-up in pressure prior to the jam indicates the blockage is most likely in the pump area. Slow pressure build-up is indicative of a jam further down the line, nearer the delivery end. The operator needs to examine the system, especially at the elbows or discharge hose. This can be done by tapping the hammer along the pipeline. Where concrete is jammed, the hammer will produce a dull thud, as opposed to a more ringing sound where the line is clear. All pipe joints should also be inspected for grout leakage, as well, as this can be indicative of grout loss and subsequent blockage. By carefully walking over or stepping on the discharge hose to depress it, a blockage may be located where the soft hose becomes firm, indicating jammed aggregate. Return to Concrete Pumping Find a Concrete Contractor 24 Services in 221 Metros -- U.S. and Canada © 1999-2012 ConcreteNetwork.com None of this site may be reproduced without written permission |
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