Contact Person : Sara Hou
Phone Number : 86-18625504560
WhatsApp : +8618625504560
September 9, 2020
1. 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 diesel concrete mixer, 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.
2. Clearing the Blockage
By alternately reversing the pump and resuming pumping for a few cycles, the pump operator may be able to break loose a minor rock jam. This should not be tried more than a couple of times, however, as it can jam the pipeline even tighter. If the reversal method doesn't work, the operator must locate the blockage, then break back the line and clear it out.
Always make sure the line is no longer under pressure prior to clearing a blockage. Stand to one side of the line and remove the coupling nearest the jam. Let all the free-flowing concrete run out of the open end of the line by lifting the line, then bend the hose or tap on the pipeline in the area of the jam and shake out loose particles.
Important safety tip: when trying to clear a line blockage, NEVER use compressed air. If a greatly increased pump pressure wont move the blockage, compressed air wont be able to either. While using compressed air utilizing proper safety precautions is OK for cleaning out unblocked sections of pipe, using it on blockages can cause all kinds of problems, including the need to relieve the built-up air pressure, residual air pockets, and additional blockages due to segregation.