Regarding the lubrication of pumps
Thread Content
I work in instrumentation, but I want to understand the lubrication issues related to pumps. Some pumps have an oil filling hole on the top and an oil drainage hole at the bottom, allowing for regular oil replacement using an oil gun. I would like to ask which part of the pump is lubricated by this oil? If it’s the motor bearings, I remember that to lubricate them, one needs to remove the bearings, open the bearing covers, clean the inside of the bearings, and then change the oil. But if it’s not the motor bearing, then what could it be? Could an expert please explain this? Sorry for the request.
For pipeline pumps, in some cases it is necessary to remove the end cover of the motor bearings in order to apply lubricant; in other cases, there are oil tubes on the end covers of the motor bearings designed for applying lubricant, with a tube for releasing the lubricant underneath. The lubricant for pipeline pumps is applied to the motor bearings. Cantilever centrifugal pumps: some are lubricated with grease while others use oil; in both cases, the lubricant is applied to the bearings of the cantilever pump
Thank you for the answer! Does it mean to add it inside the bearing? But there are requirements regarding the replacement of the lubricant in the bearings; generally, 1/2 or 2/3 of the cavity volume should be filled. If the lubricant is injected using a grease gun, the old lubricant must also be pushed out, so it’s necessary to fill the cavity completely, right? This will cause excessive oil to be ejected into the stator windings, resulting in a short circuit. I’m quite confused about this, as there are no conditions to conduct on-site disassembly and inspection. That’s why I’m consulting experts; I hope you can kindly provide some answers. Thank you!
Without a bearing cover, sealed using the small end cover of the bearing
Pump bearing grease loses volume over time due to operation, so it needs to be replenished regularly.
I would like to ask whether the bearings of the pump are the same as those of the motor it is connected to? And if oil is added using a grease gun, won’t that fill the bearing chamber?
I would like to ask whether the bearings of the pump are the same as those of the motor it is connected to? And if oil is added using a grease gun, won’t that fill the bearing chamber?
Generally, 1/2 or 2/3 refers to the oil level in the lubrication sight glass when the cantilever pump is shut down; this applies to lubricating oil, not to grease. For pumps that use grease, it is important to add the grease while the pump is running, or to rotate the pump while adding the grease, as this helps the grease reach the bearings. The dirty grease that comes out of the outlet should be replaced with clean grease once available.
The split-type pump has its own support bearings, and the amount of oil added using the oil gun is controlled as required; there’s no need to worry if it gets full, as the excess oil will flow out.