🔍 Key Concepts

• One-way flow / backflow prevention in piping systems • Basic function and internal design of gate, globe, check, and plug valves • How each valve is operated: manual vs. automatic (flow‑actuated)

💭 Think About

• Which of these valves is specifically designed so that if flow tries to reverse, the valve automatically closes without you turning a handwheel or lever? • Think about where you would install a valve to stop liquid from draining back into a pump or tank when the pump is shut down. • Of the four types listed, which one is normally used only to prevent reverse flow, not for regular throttling or frequent manual open/close use?

✅ Before You Answer

• Identify which valve type is automatic (moves by flow/pressure, not by you turning a wheel). • Eliminate any valve whose normal function is shutoff or throttling in either direction of flow. • Recall that the correct valve is commonly used as a backflow-prevention device in discharge lines and pump outlets.