What does a Worn-Out shaft Sleeve Tell you?
The wear on your pump parts tell a story.
Sleve with substantial wear
New Sleeve
A CAC customer discovered during a routine inspection that dirty sealing water had cut the shaft sleeve in half, resulting in a leak. As a temporary fix, the millwright tightened the sleeve and moved it inward. This adjustment did not stop the leak and instead created a secondary wear pattern. A second tightening prevented the sleeve from rotating entirely and produced a localized horizontal wear pattern. At this stage, it should have been clear that the sleeve was beyond repair.
Once wear patterns have formed on a shaft sleeve, repositioning it will only accelerate damage. Moving the sleeve simply relocates the groove and initiates the formation of a new one in an area affected by the same underlying issue. Similarly, tightening the gland compresses the packing and reduces the cooling and flushing effect of the sealing water. Over‑tightening only worsens conditions and can ultimately lead to component failure.
Diagnosing & Prevention
To prevent these failures, users should take proactive steps to diagnose and correct shaft sleeve issues before excessive wear occurs. This evaluation should be incorporated into routine pump maintenance to avoid premature sleeve replacement.
The first step is to inspect the sealing water system for adequate flow, pressure, and quality. CAC recommends clean sealing water supplied at a sustained pressure of 10 psi above the pump’s discharge pressure. Maintaining higher sealing water pressure prevents the pumped medium from weeping back into the stuffing box, significantly reducing shaft sleeve wear.
If flow and pressure meet specifications, sealing water quality should then be evaluated for corrosive properties or abrasive particulates. The shaft sealing system must be properly designed and applied based on these conditions.
A common misconception is equating sufficient gland water flow with proper sealing. In reality, high flow without adequate pressure is ineffective. When pump pressure exceeds gland water pressure, the pumped fluid will override the sealing water regardless of flow volume.
If shaft sleeves are wearing out at two to three times the rate of the impeller or wear plate, the root cause is typically insufficient gland water pressure or an oversized stuffing box that has experienced excessive internal diameter wear due to lack of replacement.
250-656-7788 // sales@cacindustrial.com