Maintain Pump Packing
While many situations can cause pump packing problems or failure, they can be prevented through regular inspection and maintenance. With the advent of environmentally friendly synthetic packing maintenance requirements, as well as start-up and break-in procedures, have changed. Most people don't realize how many packing problems can occur.
When starting up a pump, or a pump with new packing, it is important to consider the following factors as they can provide a warning of any potential issues during start-up or maintenance:
Age of the pump & Pump Packing: How old are the pumps? How long did the pump and packing sit prior to start-up? Pumps that sit idle for long periods of time are at high risk of having dry packing. It is advised to check pump packing prior to start-up to ensure packing has not dried out in storage.
Pump/Bearing Temperature: Bearings that continually run at increasing temperatures and do not peak out and start declining are a clear indication that there is a problem, and that the packing needs to be inspected, and potentially replaced, immediately.
Stuffing Box Maintainance
By Rick Kushinski, Service Manager
Probably one of the most overlooked preventive maintenance tasks is to change the stuffing box packing annually.
Old packing causes problems
As the packing ages, it becomes hard and brittle. In this state, it loses its ability to provide an adequate seal against the outer diameter of the shaft, as well as the inner diameter of the stuffing box. This can lead to increased air leakage through the stuffing box at higher vacuum levels or excessive seal water leakage along the shaft at lower vacuum levels. The latter can also contribute to a premature bearing failure if the leak is severe enough to allow water to enter the bearing housing. When this situation occurs, we commonly find that the packing gland has been tightened to the point of creating too much friction against the shaft, which in turn causes the metalizing on the shaft to overheat and possibly crack - making the situation much worse. At this point, the pump needs to be removed for repair.
Changing the packing annually will make the task much easier to accomplish, as the packing will still be pliable. It is also very important to remove all of the packing, and replace it with new parts. Many times, when pumps come in for repair, we find that the shaft packing rings that are easily accessible, the first two or three, have been changed out but the remaining rings were left in. This will lead to the same problems mentioned earlier.
Another Tip
While this task is being performed, make sure that the drip tray between the stuffing box and the bearing housing is not full of debris and that the drain is clear. A clogged drain will allow water tobuild up in the drip tray and possibly enter the bearing housing and contribute to a premature bearing failure.
