Study On The Effect Of Reinforced Loops On Stress Characteristics In Centrifugal Bowls

Bowl is one of the main parts of a centrifuge. The design and strengthcalculation of bowl directly affect the general service performance of centrifuge. Tomeet the requirements of strength, reinforced hoop is used on cylinder of bowl insome design and manufacture units. Thus, mastering the effect of reinforced loop onstress of cylinder is very important.On the problem of reinforcing loop, it is supposed that using loops is feasibleamong centrifugal industry standards of various countries. There are definitecalculation formulas for reinforced loop coefficient in the standards of BS EN12457,VDMA 24401-Ⅰand JB/T8051, but they have different regulations on this issue; Andpretension between loop and cylinder isn't considered in them. Besides, they do nothold unanimous opinion on the question of when loops work on the bowl and howtheywork.It belongs to contact mechanics problem of the connection between loops andcylinder. Because the distribution of stress in the connection area is very complicatedand the certain amount of interference between loops and cylinder in the condition ofpretension, it is difficult to solve the problem of bowl contact in theory. The paper hasdetermined the influence laws of these factors that include the structure anddistribution along cylinder of loop and other factors by using finite element analysismethod. And the results reveal that: no matter if there is pretension between bowl andloops, the enforcement effect of loops whose axial size is lager than the radial size(that isa ? e) on cylinder is greater than other shapes of loop in the condition of equalcross- sectional areas of reinforcement hoop. When cross section , thedepth-thickness ratio?of loop cross-section has little influence on the stress result.No matter if there is pretension between loops and cylinder, the cylinder between twoloops is being reinforced just when the loop space (which r0 representsthe mean radio of cylinderδmeans the wall thickness of cylinder). Theenforcement effect is most significant when for definitive totalcross-sectional area of loop. The two methods for reducing the stress level of bowl,one of which is enlarging the pretension and the other is increasing cross-sectionalarea are equivalent.On basis of finite element analysis, several revising suggestions of the application scope of reinforced loop coefficient Z in JB/T 8051-1996Standard ofstrength calculation for centrifugal bowl are proposed in this paper.