Have you experienced a John Crane Type 1A mechanical seal failure in a vertical pump due to inadequate venting? The seal may fail due to running dry in a vertical application without proper venting of the stuffing box. Insufficient venting of the supply tank can also cause the stuffing box to operate in a vacuum, leading to potential seal unbalance issues. It is crucial to ensure proper venting in a vertical pump application to prevent mechanical seal failures.
Hey Josh, could you please explain what a motor mechanical seal is? This term is new to me and I'd like to learn more about it.
To find out more about the definitions of mechanical seals, visit the Wikipedia page on Seal (mechanical). This resource provides valuable information on the importance and functions of mechanical seals in various industries.
The motor mechanical seal, also known as Vee seal (John Crane type 1A), is essential for preventing potable water leakage from a vertical submersible motor to a pump atop the motor. This seal is crucial in maintaining the motor's integrity and efficiency. The potable water, supplied from an overhead tank on the platform deck, not only cools the motor windings but also provides lubrication for the thrust and journal bearings. The water enters the motor at the bottom and circulates back to the tank at the top, ensuring optimal performance.
Mechanical seals are highly vulnerable to damage when they run dry due to the lack of hydrodynamic opening force. Horizontal shaft seals have an advantage as they can extract some fluid from the stuffing box, even with poor venting. Conversely, seals on vertical shafts can run completely dry unless the stuffing box is flooded, emphasizing the importance of efficient venting. To prevent issues, the vent hole in the stuffing box body must be positioned above the seal faces and of sufficient size. It is crucial to ensure that the vent hole is functioning properly to avoid heat buildup and steam formation, which can lead to seal failure. Proper venting is especially critical in vertical shaft seals to prevent dry running. Vent hole location relative to the seal face plane should also be checked regularly. Without adequate lubrication, seals can degrade quickly, regardless of the brand. Ensuring that seals remain moist is key to preventing failures, as experienced in vertical ethane pump seals where maintaining proper lubrication resolved issues effectively.
Thank you for the detailed explanation, Vee. I need to delve deeper into the concept, but one aspect is still unclear to me: How does the water manage to flow back into its tank located 30 meters above without the aid of a pump? Could it be through convection caused by the heat generated by the motor windings? Also, do you have the documentation for your ethane pump available? I have tried searching online for solutions to similar issues without success. I acknowledge that the solution does not lie in the specific brand I mentioned earlier, for easier comprehension.
Absolutely, you're on point with that! My team and I faced a similar issue with a vertical pump in our facility. We initially couldn't pinpoint why we were experiencing mechanical seal failures frequently until we discovered it was due to improper venting. Now we're diligent about ensuring proper venting in not just the stuffing box but the supply tank too. All it takes is that small negligence to cause a big operational issue. Regular maintenance and attention to detail is key, indeed.
Indeed, proper venting to prevent seal failure is a lesson I've learned the hard way. A few years back, I had a John Crane Type 1A seal fail in a vertical pump, and it was a messy and expensive issue to correct. Insufficient venting was indeed the culprit as we discovered that the supply tank operated intermittently in a vacuum state. After we upgraded our venting procedures, we had no recurrence. So, your point is spot on - it really underlines the importance of correct venting in vertical pump applications.
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Answer: Answer: The common cause of seal failure in vertical pumps is inadequate venting, which can lead to running dry and seal unbalance issues.
Answer: Answer: Inadequate venting can cause the stuffing box to operate in a vacuum, potentially leading to seal unbalance and failure due to lack of lubrication.
Answer: Answer: Proper venting is crucial as it ensures the stuffing box receives adequate lubrication and prevents the seal from running dry, ultimately extending the seal's lifespan.
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