Research On Characteristics Of Hydraulic System In Electric Control Double-pump Concrete Pump

Concrete pumps, also known as concrete conveyed pumps, are machines that can convey concrete continuously through the pipeline to the specified location relying on pressure. In modern society, they play an important role in basic constructions. They can be classified into various kinds on the basis of their hydraulic systems. In order to meet market demand, high-pressure, large displacement and intelligent control concrete pump is the current developing trend. So electric control double-pump hydraulic pumping systems are becoming mainstream hydraulic system. The products in the market, however, still have some deficiencies such as low switching consistency and low ability of regulating the displacement of piston in cylinder, which have bad effects on the performance of the system. Therefore, solving these problems will help improve the performance of the system, increase market competitiveness and provide some advice on the subsequent development of new products.Based on electric control double-pump open hydraulic pumping systems, after a series of research, a method of optimization is obtained, which can improve the performance of the system well. The thesis can be divided into seven chapters as follows:In chapter1, through the introduction of the overview of concrete pumping technology and its development and relevant background, the significance of the subject is summed up, the major research work is proposed, research objectives and technical route are developed, technical difficulties are analyzed.In chapter2, the test rig about the performance of core components is introduced. the static and dynamic performance of core elements are tested in this test bench. The performance of the core elements were analyzed according to the test data.In chapter3, simulation models of each component and subsystem are established validated through experiments. Finally, simulation model of the entire hydraulic system is established based on these verified component and subsystem simulation models.In chapter4, the simulation model of the entire hydraulic system is modified based on tested data of the system test bench in various working conditions so that the accuracy of the simulation model can achieve the requirements.In chapter5, the research on the effect of switch inconsistencies about two main valves is conducted in two aspects, which are frequency response and delayed time of solenoid pilot valve. what performances of the system does the switch inconsistencies affect are also analyzed, including the displacement of main valve spools, impact pressure of the pumps in switching and the displacement of cylinder pistons.In chapter6, according to the simulation model, displacement variation rules of cylinder pistons are researched from the perspectives of critical parameters in the system. In accordance with the rules, the performance of the system is optimized. The displacement of cylinder pistons and the function of replenishing/draining oil are improved. Furthermore, the time of the switching process is shortened.In chapter7, some conclusions about research are summarized and the future research proposals are suggested.