The concrete pump, which is characterized by a high performance level, is in a great demand from specialized enterprises. However, due to the lack of a field experience, the systems and components of this equipment regularly fail without completing the operational period. Obstruction in pipes, which leads to clogging of a concrete conveying pipe, is one of the main issues.
The reasons for this can be as follows:
1. Improper composition of a concrete mixture, which prevents its pumpability;
2. Incorrect operations of the mechanics;
3. Non-compliance of particle size distribution of aggregates with the required values;
4. Untimely replacement of wearing parts.
Obstructions can be located and eliminated as follows:
Gradual decrease in the concrete pump performance with a simultaneous increase in the system pressure. This leads to obstruction of a concrete conveying pipe in its outermost section. The obstruction is then removed by disconnecting and cleaning of the final links of a concrete conveying pipe;
In case of seepage of cement slurry through the joints of a concrete conveying pipe, the obstruction is formed downstream the link;
A sudden stop of a concrete pump indicates the occurrence of obstruction in a swing pipe of a damper or in the first link of a concrete conveying pipe behind the damper. The obstruction can be located aurally when tapping a concrete conveying pipe with a mallet. The location of obstructions is characterized by a muffled sound.
Preventive measures against obstructions in concrete conveying pipes:
1. Always check damper slabs and replace them when necessary;
2. Clear the damper;
3. In the course of design and installation of piping, use as few 90-degree angle pieces and "S"-shaped angles as possible; using 3 or more variform pipes is prohibited;
4. The composition of pumping concrete must be developed strictly in accordance with the design standard;
5. Prior to operation of the machine, the concrete conveying pipe must be washed and lubricated, and the packing must be checked;
6. If a long time is required to prepare concrete mixture, it is necessary to start up a pump and change its operating direction (forth and reverse) every 5-10 minutes in order to prevent the hardening of concrete in a pipeline;
7. In hot or cold weather, it is necessary to take appropriate measures to avoid the occurrence of pipeline obstructions.