🔍 Key Concepts

• Popping pressure vs. blowdown (how far and how fast the valve opens once it lifts) • How a compression spring safety valve develops force on the valve disc • Which parts in the illustration actually change the spring’s initial compression (preload)

💭 Think About

• Look at the load path: which part pushes directly on the top of the spring and can be moved to increase or decrease that force when the valve is closed? • Which listed parts mainly guide or shape the flow/‘snap’ action of the valve rather than changing how many pounds of force the spring exerts at the set point? • If you wanted to change the set (popping) pressure during calibration, which one of these would a technician adjust first on a test stand?

✅ Before You Answer

• Identify in the illustration which component is attached to a threaded stem or nut that can move up/down to change spring compression • Be sure you can distinguish between parts that control set pressure and parts that control blowdown or lift • Verify which option describes a part whose movement will directly change the spring preload on the valve disc when closed