The Study And Application Of Rotor Balance On A Kind Of Canned Pump

Rotor balancing is a common process in the field of general mechanical equipment.Because of its different importance,mechanical equipment is reflected in the design of the choice of high or low precision,corresponding to the rotor balance there are different levels of accuracy.Generally speaking,the more important the equipment,the higher the accuracy of rotor balancing,and the more difficult it is to realize in manufacture.This topic is selected from a large vertical shielded motor pump,which is used in the nuclear power generation technology system of the third generation of civil PWR.Vividly called the “heart” of nuclear island,it is the only power equipment in the primary circuit of the nuclear island with inactive design,which is responsible for providing power transmission for nuclear energy and heat.The safety level of the equipment is Class I nuclear level.In the field of general machinery,the design and manufacturing level of the product is also the highest.Therefore,the rotor balance grade is also the highest G1.0 level,which is far higher than the recommended G2.5 level for pump machinery.The improvement of precision brings about the difficulty of manufacturing process.In general,the difficulty increases 2.5 times.The research of rotor dynamic balance has a history of one hundred years,and the basic theory has been more mature.The direct result is the widely used balancer,which has transformed complex theory into engineering application.But this subject has its particularity,in this paper,the rotor of shielded motor is one of the rare types of general machinery in structure.Two inertial flywheels with large length and diameter are arranged on the two sides of radial support.After the rotor lies on the balancing machine,it forms a double cantilever structure,which is the most difficult to realize in the rotor dynamic balance.The local center of mass on the outside of both braces has an even unbalance effect on the near and far support points.The difficulty in reality is that the balance test was unsuccessful in the month before the start.Data cannot be reproduced,and the counterweight does not conform to the law occurs.The main research contents of this subject begin from here,after consulting the literature and returning to the theoretical analysis of rotor balance,combining with our engineering test data,the problem is gradually eliminated,reduced and focused.The influence parameters of the balancing system(engineering calibration)and the precision adjustment of the rotor position on the balancer are the solutions that we finally find.Through a series of studies,the precision of dynamic balance is finally realized.In addition to the problems encountered in the rotor balance test mentioned above,the unbalance correction of the impeller of one of the rotor parts is another problem.The initial unbalance of the casting impeller is very large,in order to achieve the balance value of the target,it cannot be achieved only by removing the weight,so the axis line migration method is introduced.On this basis,a computer program is developed to improve the accuracy of calculation to more than 90%.