🔍 Key Concepts

• Throttling vs. full-open/quick-open service in valves • Internal flow path and seat design of gate, globe, check, and plug valves • Which valve types are normally used for isolation only, and which are used for flow control

💭 Think About

• Think about which valve type is designed to operate partially open for long periods without damage or excessive wear. • Consider the internal shape of each valve: which one forces the flow to change direction, creating better control but more pressure drop? • Ask yourself: which of these valves is normally used where you want to regulate flow rate, not just turn the flow fully on or fully off?

✅ Before You Answer

• Identify which valves (from the list) are typically used as on/off isolation valves rather than for control. • Recall which valve is most associated with precise flow regulation in engineering and piping diagrams. • Eliminate any valve whose primary purpose is non-return (prevent backflow) rather than manual control.