I would like to ask for expert advice: regarding the selection of angular contact paired bearings during the major overhaul of twin-screw pumps
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I would like to ask a sophisticated question: during the major overhaul of twin-screw compressors, how should angular contact paired bearings be selected? What will be the consequences if two corner contacts are used arbitrarily without pairing?
Could the direction of the axial force change?
Check the model in the manufacturer’s manual, and then select it in SKF’s selection manual
If two angular contact bearings are selected arbitrarily, the clearances between these two bearings will not match, which accelerates the wear of the bearings.
The original bearings must be used; they are designed this way, and even professionals do not dare to use alternative ones casually
Taking SKF bearings as an example: for the 7312B and 7312BECBP models, the contact angle is specified as 40° only, with no indication as to whether they can be arranged face to face, back to back, or in series. 7312BECBP specifies that they can be connected face-to-face, back-to-back, or in any series configuration. In practice, for the high-temperature oil pumps in the distillation section of our hydrogenation plant – which are single-stage, double-supported pumps – the bearings that were removed were of type 7312BECBP. The plant wanted to use 7312B bearings instead, but the technicians prevented this from happening. If the 7312B is used, the axial force will likely cause rapid damage to it; coupled with high-temperature oil, the risk is too great. Therefore, it’s better to wait until the 7312BECBP is purchased before reinstalling it.
Mated bearings have the clearance range predetermined at the time of manufacture. For ordinary bearings, the amount of play between any two bearings that are installed face to face or back to back is uncertain; it is necessary to use shims in order to adjust the play to the desired level. This requires extensive technical expertise, which is why manufacturers produce paired bearings. If the clearance is not appropriate, the bearing’s lifespan will **decrease**.