🔍 Key Concepts

• Globe valve flow vs. stem travel – how the passage opens as the disk lifts off the seat • Difference between linear, equal-percentage, and quick-opening throttling characteristics in control valves • How the small initial opening area near the seat affects flow change at low openings

💭 Think About

• Visualize the cross‑section of a globe valve and imagine how the flow area changes as the disk first cracks open, then moves farther from the seat. • Ask yourself: does a small movement near the closed position cause a big change or a small change in the flow area? What about a similar movement near the almost‑wide‑open position? • Compare what "first third of travel" and "last third of travel" would mean to the size of the opening and resulting flow rate.

✅ Before You Answer

• Be clear on whether a typical globe valve is considered good for throttling (fine flow control) and why. • Think about whether the valve is most sensitive to small movements when it is nearly closed or nearly fully open. • Check which option matches a valve where initial opening has a strong effect on flow versus one where most change happens near full open.