🔍 Key Concepts

• Look at how the disc or closure member is mounted in the illustration (is it hinged, lifted straight up, or is it a ball or piston shape?) • Consider how the valve would open when flow moves forward and how it would close when flow reverses based on that mounting method. • Compare the shapes and motions of ball, lift, swing, and piston check valves in standard marine engineering diagrams.

💭 Think About

• What part in the drawing actually blocks the flow, and around what point does it move? • Does the closure member swing in an arc, lift vertically, slide like a piston, or roll like a ball when the flow changes? • Which of the four listed valve types is specifically designed so the disc moves in the same way shown by the dashed motion lines in the figure?

✅ Before You Answer

• Identify whether the moving piece is a flat/curved disc on a hinge, a ball, a piston-shaped plug, or a vertically guided disk. • Trace the dashed motion path of the closure member in the illustration and match that to the typical motion of each valve type. • Verify that the body shape and internal clearance allow the full travel shown for only one of the listed valve designs.