🔍 Key Concepts

• Location and orientation of petcock B relative to the pump casing and discharge passage • Normal reasons for installing a small petcock or bleed valve on a centrifugal pump • Difference between a main flow/recirculation line and a small vent/drain/sampling line

💭 Think About

• Look at where petcock B is connected: Is it tied into the stuffing box, the discharge, or a control line? What does that tell you about its job? • Which of the choices would realistically be done through such a small valve, and which would normally require a larger dedicated line or specialized instrumentation? • When starting a centrifugal pump that might contain air, what small manual operation is often done at the highest point of the casing or priming line?

✅ Before You Answer

• Verify whether petcock B is at or near the highest point of the pump casing/priming line, where air would naturally collect. • Check if there is already a separate line and valve (marked A) leading to the stuffing box; if so, consider what that line is likely used for. • Ask whether a tiny petcock is sufficient to control discharge rate or provide significant recirculation flow, or whether its size suggests a minor function like venting or sampling.