Research On A New Regulating System For Adjustable Profile Axial Fan And Its Application

Adjustable profile axial fan has the advantages of high pressure,large flow,high efficiency,wide adjustment range,reasonable structure,high reliability and good comprehensive economy,which is widely used in thermal power plants,steel plants,mines and other industrial systems.At present,the adjustable profile axial fan uses the actuator to drive the connecting rod mechanism to adjust the position of the servo valve,so as to control the oil inlet and return direction of the hydraulic oil,and then control the forward and backward of the hydraulic cylinder piston,and then drive the rotation adjustment of the blade through the blade adjustment device connected with the piston.Generally speaking,it is a electro mechanical adjustment system.In the actual operation process,there are several problems: first,there are many mechanical fault sources,and the adjustment accuracy is poor.There are many mechanical connection points from the actuator to the servo valve,which may lead to faults.In practice,there are real-time faults such as connecting rod fracture,bending,connecting pin falling off,joint bearing wear and so on.At the same time,due to the looseness and wear of the mechanical connection,there is "position drift" after a period of time,which leads to the actual position and feedback position of the blade different;second,the actuator can not be replaced online during the operation of the fan,once breaking down,the system can only be stopped for replacement or repair;third,the servo valve wears fastly,and the increase of internal leakage after wear will lead to oil pressure fluctuation;fourth,the blade position cannot be locked after the hydraulic oil fault,so it can only be stopped for treatment.Once the fan is shut down,the whole industrial system will stop running,resulting in huge economic losses.In this paper,a new type of adjustable profile axial fan regulating system is designed to solve the problems of many mechanical faults,inaccurate adjustment,fast wear of servo valve,and unable to lock the blade position after oil circuit fault in the current general actuator plus linkage regulating system.The main contents of this thesis are as follows:(1)According to the TRIZ theory,it has been analyzed that the shortcomings of the current regulating system of the adjustable profile axial fan,and proposed a new regulation system which adopts electro-hydraulic control instead of the original electro mechanical control with actuator and servo valve,and adopts hydraulic control check valve for hydraulic locking.(2)According to the technical proposal of the new regulating system,combined with the characteristics of the existing adjustable profile axial fan regulating system,the overall structure diagram and function diagram of the new regulating system are designed.(3)According to the overall structure diagram and function diagram of the new regulation system,the design and research of key parts are further completed.It mainly includes the design of rotation union,the selection of proportional valve and position sensor,the installation of position sensor and the design of main structure of new regulating device.(4)According to the overall structure diagram and function diagram of the new regulating system,the design of the oil system and the control system is further completed,and the parameters of the oil system are calculated and studied;The control strategy of the control system is compared and the PID control strategy is determined,and the control mode and control parameters are studied.(5)After the completion of the design,the trial production of the product is carried out,and the function of the product is verified through the factory model test and user field test.Finally,according to the user-feedback,the direction of further optimization is put forward.