Regarding the issue of forward and reverse rotation of mechanical seals
Thread Content
There is currently a BB2-type centrifugal pump with API specifications, equipped with mechanical seals on both the drive side and the non-drive side, each having a single face. After repairing the mechanical seals at both ends, it is not possible to determine whether the two mechanical seals are on the drive side or the non-drive side. Dear sea friends, does reversing a mechanical seal have any impact? Can it be detected from the spring of the driven ring?
I really haven’t paid attention to it; I guess not
Only those with large springs and driven by springs have a distinction between forward and reverse rotation; for others where no special emphasis is placed on distinguishing between forward and reverse rotation, there is generally no issue!
Where are machine seals produced that don’t have a steel stamp? Does a pump with dual supports really not have markings for the drive side and the non-drive side? If the manufacturer doesn’t have a steel stamp, it’s possible that the pressure rating is the same; there might be no difference after all. It’s better to get in touch with the manufacturer to ask ； Anyway, the mechanical seals of the multi-stage double-support pumps that I have repaired are different from each other and cannot be mixed up; the O-ring on the side with higher pressure is thicker, and the PTFE ring is also thicker there
Generally, there are clear markings when removing the machine seal, as the materials on the material-side and the non-material-side are different. Factors such as temperature, the properties of the material, and pressure are taken into consideration. If no markings are present, it is possible to consult the supplier. As for determining which side is the correct one based on the shape of the spring,
The reversible operation of the seal is generally not affected, as long as there is no indication that reversal is not allowed. For your double-faced mechanical seal, you still need to check each sealing surface; there is a difference between the drive end and the sealing section
1； BB2 pumps typically use small springs or modular mechanical seals, and neither is affected by the rotation direction. 2 ； The driven and undriven ends of a modular unit with high head should be differentiated 【with different balance values selected during design】. The mechanical seal should also have clear markings; if not, both ends should be the same
This is related to several factors. For the pump in BB2, the pressure in the sealing chamber is equal to the inlet pressure; therefore, the sealing selection is usually the same. It’s generally not possible to tell this from the spring alone. However, in cases where there is a pumping ring, such as in hot-water applications (Plan23), there are usually requirements regarding rotation direction. Additionally, in the case of modular seals, the positions of the openings on the end caps, such as F, Q, and D ports, may also vary. Sealing manufacturers provide specialized drawings that indicate whether there is a drive side and a non-drive side
It’s best not to get it reversed; even though there are no effect rings that require a specific direction, the flushing process still has a directional requirement. If it’s reversed, the flushing fluid will rotate only 1/4 of a turn instead of 3/4 of a turn.
If it’s a double-seal, the impact is significant; I’ve encountered cases where it was installed in the wrong way, and it had to be adjusted back, which affects its lifespan