Energy Recovery And Reuse Of Luffing Mechanism For Full Hydraulic Boom Tower Crane

When traditional flat-head or tower-head cranes work,they require more space.Therefore,they are not suitable for small space loading operations.In contrast,the boom tower crane has more flexible boom frame and stronger lifting capacity.In view of the more obvious advantages,it has become an indispensable lifting equipment for high-rise building construction.If the electric drive is used in the boom tower crane,it will have an impact on the grid of nearby buildings.Therefore,the power source of the boom tower crane is generally a diesel engine,and the transmission and control are relied on the hydraulic system.However,the diesel engine has large displacement and high fuel consumption.In turn,the pollution to the environment is more serious than other industries using internal combustion engines.Energy saving and environmental protection is a basic element for construction machinery to enter the market.Energy saving technology of construction machinery will bring considerable economic and social benefits to the country,society and users.For a long time to come,energy conservation and emission reduction will become an important research direction of construction machinery industry.This paper takes the STL2400 full hydraulic boom tower crane with a maximum lifting moment of 2400 tm as the research object.When the boom is lowered,the potential can be consumed by balance valve orifice,then radiates into the system in the form of thermal energy to raise the temperature of the oil,which causes energy loss and waste and adversely affects system operation.If this energy can be recycled,it can not only improve the efficiency of tower crane hydraulic system,but also achieve the purpose of energy saving and emission reduction.Based on the original luffing system of the tower crane,using the four-quadrant working characteristics of the secondary element pump/motor,configuring the pressure of the accumulator in three-stage,a potential energy recovery and reuse system for the boom of the luffing mechanism is designed.Instead of being consumed by balance valves,the boom potential energy is converted into oil pressure energy and stored in an accumulator in this system.The energy recovered by the accumulator can also drive the rotary system and heat dissipation system of this tower crane,so the recovery and reuse of the potential energy of the boom is realized.The energy recovery and reuse system model of the luffing mechanism is built by using AMESim simulation software to perform the simulation analysis.Firstly,the correctness of the model is verified.Secondly,the parameters of the accumulator are matched,and it is most effective to recycle the potential energy of the boom for configuring the pressure of the accumulator in three-stage by simulation.The flow rate variation trend of the pump/motor of the energy recovery system is consistent with the original system luffing motor,the pump/motor speed is smoothly switched when each level of accumulator is switched,and the maximum flow error is only 1.75%,so that the tower crane work performance is better,the potential energy recovery rate of the boom can reach 55.82%.Finally,the oil recycled in the accumulator is reasonably reused to the rotary system and the heat dissipation system,and an energy reuse system is designed.Through the use of the pressure switch and solenoid valve,the energy reuse system realizes automatic control,the recycling rate of the recovered boom potential energy can reach 77.60%,and the energy saving rate of the slewing system and the heat dissipation system can reach 17.2%.The research on energy recovery and reuse of luffing mechanism in this paper also has reference significance for other engineering machinery hydraulic system energy-saving design research.