What is the relationship between the balance disk clearance of a multi-stage pump and the bearing clearance?

This post was last edited by tie008 on 2018-1-1 10:23. Are the clearances of the semi-rotating disk and the balance disk the same? On the condition of being fixed, the stringing amount should be slightly larger than the gap of the balance disc ； What is the bearing clearance after the back-to-back bearings are fixed? In the DB mounting style, the bearings need to be pre-tightened (the pre-tightening amount should ensure that there is no gap between the outer rings of the two bearings; a slight degree of tension is sufficient. The inspection method: the two outer rings must not be able to move relative to each other) ； ) The clearance at this point is related to the bearing model and specifications~~~ For the commonly used 7310BDB, it is roughly 0.07mm±0.01mm~~ The half-thrust distance is usually a little over 2mm; is this the actual axial movement range during the operation of the balance disk? Same as the first question ； If so, wouldn’t the shaft shift around inside the bearing? I understand the ways in which shaft positioning is achieved: either through thrust bearings or through balance discs~~~~ If it’s the latter approach, then there are no thrust bearings, which is ideal; the axial forces are all dynamically balanced by the balance disc through the axial throttling gap~~~ But when the balance disc comes into contact with the balance plate, there should still be at least 0.5 mm+ of clearance on the side where the impeller and the volute are relatively close to each other~~~