Hydraulic Elevator Of Energy-saving With The Closed Circuits

Hydraulic elevator is one of elevators and it has become increasingly popular in Europe. However, considering environmental protection and energy-saving, the hydraulic elevator with large installed power and high energy consumption can not be widely applied at present. Therefore, the key interest of the hydraulic elevator is aimed at the reduction of its energy consumption and the realization of its high efficiencyIn this paper, the hydraulic elevator of energy-saving with closed circuits is proposed using hydraulic counterweight, VVVF control and cylinder lifting technology. The paper contents include the enhancement of system efficiency, the reduction of energy consumption and oil quantity, the realization of pumping station miniaturization and the assurance of speed control performance and so on. Not only the proposed method of energy-saving can be applied to the hydraulic elevator, but also to the other mechatronic system. Furthermore the article is of great value academically and practically.In chapter 1, the history and current research status of the hydraulic elevator are introduced based on a lot of the publications and conference papers. The energy-saving technology of the hydraulic elevator is mainly described, and the new hydraulic elevators at home and abroad are analyzed. The research aim and significance are described.In chapter 2, the hydraulic elevator of energy-saving with closed circuits is proposed, which is a new elevator with being equal to hauling elevator in the installed power and is characteristics of lower energy consumption and oil quantity used. The system of the hydraulic elevator is designed, including the subsystem of mechanical lifting, hydraulic power and control, electrical and electronic control. According to the requirements and technology specifications of the hydraulic elevator, the system rig is set up.In chapter 3, the motion of system links is analyzed, and electric equation, dynamic equation, flow continuous equation and simulation model are set up. The elevator speed, pressure distributions in the closed circuits, effects of oil temperature on the elevator speed and the effects of static and dynamic frictional forces on the elevator speed are analyzed using the Simulink of Matlab.In chapter 4, the experimental research of the effects of the parameters of main hydraulic components on the control performance of the elevator speed is carried out. The relationships between gas pressure and volume in the pressure accumulator under the conditions of the state of constant temperature and thermal isolation are measured, and practical gas polytropic exponent is fitted. The effects of oil temperature on the accumulator pressure are analyzed in details, the range of the accumulator pressure is given by experiments, and the setting method of the accumulator relief pressure and the supplemental oil method are proposed to ensure that the accumulator pressure keeps a constant. Four kinks of frequencies in the system are measured, and the reason for oil temperature rise is analyzed and the experienced calculationformula of oil temperature rise is given. The vibration and noise of the elevator's ascending and descending are measured and the solution to solving the elevator vibration and noise overproof is proposed. The elevator stable starting, stopping and speed stability are investigated. In particular, experimental studies are carried out aiming at the elevator speed control performance and energy consumption. In the speed control, the effects of both oil temperature and load on the elevator speed are mainly studied and analyzed. In energy consumption, the characteristic of the energy consumption for the elevator links is analyzed in details, and the evaluation results of the elevator are given. Also the speed control performance and the energy consumption of the elevator are studied theoretically and experimentally.In chapter 5, the volume of pressure accumulator, pressure setting, the rated power of electrical motor and their function relationships are respectively derived according to the elevator operation. Based on the proposed elevator principle and the improvement of the system redundancy reduction, two kinds of improvement methods are proposed focus on the structure of main control valve, and one of two is studied experimentally. Furthermore, a new kind of main control valve is proposed for meeting the requirements of the convenient integration and the system safety.In chapter 6, some conclusions are given and some new views are put forward in the future.