Fan bearing vibration is a common failure in operation, the vibration of the fan will cause damage to the bearing and blade, bolt loose, casing and duct damage and other failures, seriously endanger the safe operation of the wind turbine. There are many reasons for the vibration of fan bearings, such as the analysis of the reasons for different reasons to take appropriate treatment, often can play a multiplier effect. The failure rate of the centrifugal fan in the use of vibration is up to 48.6%. The vibration will cause the fan operation is not balanced, the bearing sleeve with the adjustment of misconduct, will cause the bearing vibration and abnormal temperature rise.
Bearing internal clearance is too small or the mechanical design and manufacture precision are poor, is the main cause of the high temperature operation of fan bearings, for the convenience of the fan installation, overhaul and maintenance, generally in the design of multi use sleeve bearings with inner ring of the bearing seat hole, but also easily because of the neglect of the installation program there is a problem, especially the appropriate gap adjustment. Bearing internal clearance is too small, the operation temperature rises sharply: the inner ring of the bearing sleeve with taper and loose, bearing easily because of loosening and failure to face with short-term loss.
Two, the replacement of fan impeller
Replacement of the fan impeller, such as equipment maintenance. Fixed fit between the two sides of the impeller with the fixed sleeve and the bearing seat. Try machine on the free end bearing temperature rise, high value of vibration fault, open the bearing cover plane, manual slow rotary fan, found in the roller shaft at a specific location, in the non load region is rolling, so can determine the bearing running clearance changes and high installation clearance may be insufficient. The measurement that the bearing internal clearance is 0 04mm, to 0 08mm uranium eccentric; because of the left and right bearing span, to avoid the error of shaft deflection or bearing installation angle.
Three, roller bearing
However, when the internal clearance of the bearing is insufficient, the inner part of the bearing is restricted by the movement space, and the automatic centering function is affected, and the vibration value is increased. Bearing internal clearance decreases with the increase of the degree of tight fit, can not form a lubricating film song, when the bearing running clearance due to temperature rise and drop to zero, if the bearings run the heat generated in the heat dissipation is when the bearing temperature is rapidly climbing. This is to stop immediately, otherwise it will damage the bearing, bearing inner ring matched with the shaft of the bearing is too tight wood cases of abnormal high temperature operation. Treatment, the withdrawal of the tight set, re adjustment of the shaft and the inner ring of the fit, the replacement of bearings after the clearance of 0.1 Ommo re installed to start the fan, bearing vibration values and operating temperature will return to normal.
Four, treatment of non working area of the blade ash
This kind of defect is common in the boiler induced draft fan, the phenomenon is mainly manifested in the fan vibration in the operation of the sudden rise. This is because when the gas enters the impeller, there exists a certain angle and rotating blade working surface, according to the principle of fluid mechanics, gas in the non working surface of blade must be produced in the gas vortex, and soot particles due to vortex interaction will slowly deposited on the non working surface. Wing type blade is the most easily accumulated ash. When the ash is up to a certain weight, the centrifugal force of the impeller will be a part of the ash deposit thrown out of the impeller. Due to the fouling on each blade can not be completely uniform, gray block time aggregation or can be thrown away some synchronization results because the blade fouling due to the uneven distribution of mass balance of the impeller, thus the fan vibration increases.