The mechanical seal of the pump is worn – why is it necessary to distinguish between the drive side and the non-drive side?

Classified according to the direction of the drive mechanism, the end that is closer to the drive mechanism is called the drive end, while the end that is farther away from the drive mechanism is called the non-drive end.

Although the sealing specifications at both ends are sometimes the same, the operating conditions at those ends can vary slightly due to the pump’s design; as a result, the wear of the seals at each end differs

I don’t understand why there needs to be a distinction; whatever is broken needs to be replaced. And the reason for the problem needs to be investigated. As for the claim of wear and tear, it’s not entirely accurate; if wear can be detected on the machine cover, then one truly has excellent control over it – being able to notice such wear indicates that one is a master at what they do. Because it was found that the wear had left it almost unrecognizable; it was completely ruined. The key issue is whether the contact surface between the rotor and the mechanical seal is smooth and free of damage; this is the most important factor. The same is true for the stator. It’s better to focus attention on this. As for which side, it’s just a code name. The surface of the mechanical seal need not be considered, unless the operating conditions differ from those for which the seal was designed.

Wear of mechanical seals is caused by excessive preloading of the rotating ring, particle wear, idling, or quality issues with the material itself. The principles behind them and their installation are not complicated; trying to analyze them in detail only serves to confuse things.

Only the drive ends, BB1 and BB2, are cantilevered; there isn’t much difference between the drive ends and the non-drive ends for BB3, BB4, and BB5. The pressures at the drive ends and non-drive ends differ for these last three components

“The key issue is whether the contact surface between the rotor and the mechanical seal is smooth and free of damage; this is the most important factor. The same is true for the stator. ”Could this sentence be explained in a bit more detail? I didn’t quite understand it. Please~

After the first occurrence of damage to the pump seal, this area needs to be inspected. The focus of the inspection is to check whether the surface at the point where the seal contacts the rotor shaft is damaged, as well as the contact surface between the seal and the stator. Relatively speaking, a mechanical seal should have three sealing surfaces: one is the sealing point between the stator and the seal, known as the static sealing point; another is the dynamic sealing point where the seals are connected to each other; and the third is the sealing point between the seal and the shaft, referred to as the relative static sealing point. These three sealing points mainly focus on dynamic sealing points; when replacing spare parts, the contact surfaces of the two static sealing points and whether they achieve proper sealing are often overlooked. In other words, after the seal is damaged, whether it affects the contact surfaces of the two static seal points. The key point is that the contact surfaces on the shaft may wear out on the left and right; once leakage occurs in these areas, it will affect the service life of the mechanical seal. Therefore, it is necessary to check the surface finish of the perimeter to ensure it has not been damaged. In the case of normal wear, No. 0 sandpaper, or even finer grits, should be used to accordingly extend the service life of the mechanical seal. It’s worth a try.

For single-stage, double-suction, double-support pumps, it doesn’t matter whether they are driven or not, as the structure and stress conditions of the mechanical seals at both ends are the same. However, for pumps with multi-stage double support, the forces acting on the mechanical seals at both ends are different, as is the pressure in the seal flushing pipes; therefore, it is necessary to conduct analysis, especially when considering operation with variable frequency starting.