🔍 Key Concepts

• Non-rising stem gate valve construction and how the disk moves when the stem turns • Why operators sometimes "back off" slightly after fully opening a valve • The difference between ensuring full flow and preventing the stem from jamming or seizing

💭 Think About

• Think about what happens inside the valve body when the stem stops moving upward but the hand wheel keeps turning a bit more. • Consider how thermal expansion or corrosion could affect a stem that is left hard against its mechanical stop. • Ask yourself which option best balances getting full open flow while still allowing the stem and gate to move freely later.

✅ Before You Answer

• Verify which choice avoids leaving the stem jammed or bound at the end of its travel. • Check which option would make it easier to close the valve later, even if it is hot or slightly corroded. • Eliminate any choice that could place unnecessary stress on the stem threads or gate when the valve is fully opened.