🔍 Key Concepts

• Stuffing box and packing around the pump shaft and what keeps it cool and lubricated • Role of the seal water/packing gland line controlled by valve "A" in a centrifugal pump • How air leaking in around the shaft can affect suction when the pump is lifting from below

💭 Think About

• Trace the small line from valve "A" and see exactly where it leads on the pump. What part is that feeding? • If no liquid flows through that line, what happens to the packing temperature, lubrication, and any air spaces around the shaft? • In a suction‑lift installation (pump above the liquid level), how would air entering through worn or dry packing affect the pump’s ability to maintain suction?

✅ Before You Answer

• Identify which component in the drawing is the stuffing box/packing and which is the shaft sleeve • Decide whether valve "A" being closed would stop cooling and lubricating flow to that area • Consider whether loss of this flow could both increase wear and allow air leakage that might break the suction when pumping from below