Massachusetts Wastewater Practice Exam

In the context of repacking a centrifugal pump, the placement of the water seal ring is critical for ensuring optimal operation and preventing leaks. The water seal ring should align with the water seal pipe hole. This placement is essential because it allows the cooling and lubrication water entering through the seal pipe to effectively reduce the temperature and lubrication of the packing rings, thereby prolonging their life and enhancing the overall sealing capability of the pump.

The water seal ring acts as a barrier, preventing process fluid from leaking out of the pump while allowing for the necessary lubrication to minimize friction. Proper alignment with the water seal pipe hole ensures that the water can flow correctly to maintain the effectiveness of the seal. If the water seal ring is misplaced, it could lead to insufficient lubrication or cooling, resulting in premature packing wear or failure.

In contrast, packing the water seal ring after the first or second packing ring would not provide the necessary alignment with the water seal pipe, impairing its function. As for the notion that it may not be necessary in a newly packed pump, this assumption overlooks the importance of consistent seal integrity and performance that the water seal ring is designed to maintain. Thus, ensuring proper placement aligned with the water seal pipe hole is essential for effective pump operation.