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Hello all,

 I will appreciate your assistance as it applies to a consistent issue we facing with our centrifuge decanters for solids - liquids separations. Our specific decanters were designed to prevent ingress of contaminants and egress of lubrication (which is in the form of dosing lube oil) within the bearing chambers.

Following production cycles, we carry out Clean - in - place which utilizes caustic acid. We have MTBF of almost every three months, and OEM claims that the caustic foam formations penetrates through the labyrinth and gets within the bearing chambers, thereby causing havoc/damage to the bearings and its housing. They claim that the caustic liquid wont be able to penetrate the labyrinth and find its way to the bearing chamber, but the foam would. 

Would appreciate anyone's assistance with experience with labyrinth seals. How would bearing isolator labyrinth seals be susceptible to foam ingress but not fluid (caustic ingress).

I have experience only using labyrinth seals in dusty environments, in such situations, we replenish and fill its cavities with grease to repel any external containments from penetrating and causing damage to the bearings. But in the case of the decanters, the only media that flushes within the labyrinth is water during the CIP phase. And it has a dedicated groove where the water expels from the seal.

Kindly see attachment.

Many thanks,

Dammy

Good Day

Interesting problem you have here.

As you are probably aware, the caustic liquid foam, is much lighter than the actual liquid, and may get stuck in the labyrinth. As the foam expands, it may push its way through the labyrinth towards the bearing. Centrifugal force is likely to prevent the actual liquid from penetrating.

Maybe reconsider the caustic liquid you are using. Ensure it has the correct sequestering agents, to prevent soap 'scum' from forming. If you get rid of the foam, your problem should be solved.

There are so many chemical companies these days, and it may be that your procurement team is not aware of the differences between the product being used, and the more expensive equivalent, containing the correct sequestering agents.

Regards

Hello all,

 I will appreciate your assistance as it applies to a consistent issue we facing with our centrifuge decanters for solids - liquids separations. Our specific decanters were designed to prevent ingress of contaminants and egress of lubrication (which is in the form of dosing lube oil) within the bearing chambers.

Following production cycles, we carry out Clean - in - place which utilizes caustic acid. We have MTBF of almost every three months, and OEM claims that the caustic foam formations penetrates through the labyrinth and gets within the bearing chambers, thereby causing havoc/damage to the bearings and its housing. They claim that the caustic liquid wont be able to penetrate the labyrinth and find its way to the bearing chamber, but the foam would. 

Would appreciate anyone's assistance with experience with labyrinth seals. How would bearing isolator labyrinth seals be susceptible to foam ingress but not fluid (caustic ingress).

I have experience only using labyrinth seals in dusty environments, in such situations, we replenish and fill its cavities with grease to repel any external containments from penetrating and causing damage to the bearings. But in the case of the decanters, the only media that flushes within the labyrinth is water during the CIP phase. And it has a dedicated groove where the water expels from the seal.

Kindly see attachment.

Many thanks,

Dammy