A beginner in mechanics seeking information on centrifugal pumps
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I have some questions regarding centrifugal pumps; I hope the more experienced colleagues can give me some guidance! For horizontal centrifugal pumps: 1. Are there bearings at the motor drive end and the non-drive end? How is lubrication achieved? 2. The pump drive end has bearings as well as a mechanical seal; it seems that the mechanical seal also serves as a supporting shaft (similar to a sliding bearing). Then why is another bearing needed? Moreover, the bearing is located in the middle bearing housing, and both the motors and pumps on either side have their own supports; it seems like the bearing housing is redundant? Moreover, the bearing box is in the middle, and the rotating shafts can be seen on both sides of the bearing box. How does it provide support? Could you explain what’s going on? 3. Is there a bearing or seal at the pump’s suction inlet? If not, it seems like the impeller has no support at the inlet. 4. I’ve never really understood the principle of mechanical seals. Is the stationary ring of a mechanical seal mounted directly on the shaft or on a sleeve? The rotating ring has a sleeve on the shaft; is there sliding friction between it and the shaft? If it is sliding friction, then how is it lubricated? Can this mechanically sealed sleeve serve as a bearing? There is a smooth friction surface between the rotating ring and the stationary ring of a mechanical seal; how is lubrication provided between them? It seems there is a gap between the mechanical seal and the shaft, as well as a gap between it and the pump casing – how is it able to provide sealing in both cases? 5. Do vertical pumps not have bearings, and is only one seal required? There are quite a few questions, and they’re a bit basic, hehe. I hope you can kindly offer some guidance!
This post was last edited by smlx1978 on 2018-7-12 at 21:40. 1. There are bearings at both the motor drive end and the non-drive end; the type of lubrication depends on the structure of the motor and the bearings. 2. The pump drive end is equipped with bearings and a mechanical seal; the mechanical seal does not serve as a support shaft. Bearings are located at both the left and right ends of the bearing housing. 3. The pump’s suction inlet lacks bearings or seals. The impeller is supported at the suction inlet through a bearing housing. 4. The mechanical seal does not serve as a bearing. There is a smooth friction surface between the rotating ring and the stationary ring of a mechanical seal; are they lubricated by the material flowing through? There is a gap between the mechanical seal and the shaft, as well as a gap between it and the pump casing; this gap is sealed off by an “O” ring. 5. Vertical pumps have bearings. The above are my personal opinions for reference only. Perhaps many pumps I haven’t seen are not structured this way.
The pump and the motor are connected by a coupling.
1. Both the drive end and the non-drive end are equipped with bearings; the manufacturer decides on the lubrication method； 2. The mechanical seal does not provide support; the bearing housing is used to house the shaft, and it is the bearing housing that supports the shaft, with the shaft serving the purpose of transmission. 3. The suction inlet of the centrifugal pump has no bearings; the impeller is fixed to the shaft, which is supported by a bearing housing ； 4. A mechanical seal is a device that prevents fluid leakage, consisting of at least one pair of friction pairs perpendicular to the axis of rotation; these friction pairs remain in contact with each other and slide relative to one another under the action of fluid pressure and the elastic force (or magnetic force) of a compensation mechanism, as well as with the assistance of auxiliary seals. The friction surface that remains stationary relative to the shaft is known as the static ring, while the friction surface that rotates together with the shaft or its sleeve is called the dynamic ring. Generally, the static and dynamic rings are lubricated by a liquid film formed between their friction surfaces, thanks to a medium or externally supplied flushing fluid. The gap between the mechanical seal and the shaft, as well as between the mechanical seal and its housing, is sealed using sealing methods such as O-rings. 5. Like horizontal pumps, vertical pumps also have a bearing housing, bearings, shaft, etc
Your questions are quite pointless.