Experimental Study on Pulse Elimination of Concrete Pumping

Abstract

During concrete pumping, traditional concrete pumps generate pulses due to the swing of the distribution valve and other factors. The pulse phenomenon in concrete pumping leads to poor application performance and limits its use in various fields such as buildings, mines, and tunnels. This paper summarizes the main causes and influencing factors of concrete pumping pulses through theoretical analysis. The overlap between the feed port and the main concrete cylinder during the swing of the distribution valve is eliminated through structural design. Additionally, a sealing baffle is designed to address pressure relief and backflow issues in the concrete pumping process. Simultaneously, a method of peak clipping and valley filling is proposed. The concrete pulse is mitigated by adding an auxiliary concrete cylinder, resulting in the design of an impulse-free concrete pump. Experiments were conducted using a traditional plunger-type concrete pump, an ant-relief pressure-type concrete pump, and an impulse-free concrete pump. Experiments on piston movement speed, pumping pulses, and pumping volume were performed. Research results indicate that sealing the distribution valve eliminates backflow and pressure relief. Furthermore, the dwell times of the three experimental devices are ranked as Δt2>Δt1>Δt3. The stop time of device Δt3, an impulse-free concrete pump, is minimal, primarily due to partial air intake during the suction of the main cylinder piston, resulting in incomplete filling of the concrete cylinder. This aspect will be a focal point for future research. In the pumping volume experiment, the impulse-free concrete pump’s volume increases more rapidly over time. During the main cylinder pump stop interval, supplementing the material with the auxiliary cylinder effectively eliminates pumping pulses of the plunger-type concrete pump, enhancing pumping efficiency. In conclusion, this study validates the design of the impulse-free concrete pump, advancing impulse-free concrete pumping technology. This research holds significant implications for the development of impulse-free concrete pumping technology. Furthermore, this research lays crucial groundwork for the application and intelligent development of impulse-free concrete pumping technology in concrete pumps, pump trucks, concrete spraying, and concrete three-dimensional (3D) printing. This study proposes a method for eliminating pulses in plunger-type concrete pumps by (1) designing a distribution valve sealing baffle, and (2) designing an auxiliary concrete cylinder and a new distribution valve structure. Based on this design approach, tests were conducted on piston motion speed, pumping pulses, and concrete delivery volume. The results demonstrated that the motion of the primary and auxiliary concrete cylinder pistons can be effectively synchronized according to design principles. Furthermore, the impulse-free concrete pump achieves continuous and stable concrete delivery, significantly enhancing pumping efficiency. The results of this study fill the gap in pulse elimination technology for plunger-type concrete pumps. The impulse-free design of concrete pumps can be applied in various fields such as concrete pump trucks, conveying pumps, and concrete spraying machines. The impulse-free concrete pumping technology can prolong the service life of pump truck booms and promote the intelligence of concrete pumping and spraying processes. Additionally, the findings of this study can be applied to material conveying in concrete 3D printing, addressing the issue of using coarse aggregates in 3D printing materials.