š Key Concepts
ā¢ Study the flow path from INLET (II) to OUTLET (III) and how parts A, C, and D control that flow.
ā¢ Think about how pressure on the top and bottom of a valve disc affects whether it opens or closes (force = pressure Ć area).
ā¢ Notice what happens when the lever E is pushed: which part actually moves first, and what that does to pressures in chambers I, II, and III.
š Think About
ā¢ Which component actually touches or is linked to the lever E? Does E act directly on C, or on something that changes pressure above C?
ā¢ If chamber I is connected to chamber II through restriction H, what happens to the pressure in I when a small valve opens and lets water go from I to III? How would that affect the force on the diaphragm and valve C?
ā¢ For each choice, ask: does it match a typical pilot-operated pressure control valve where a small pilot valve changes pressure on top of a larger main valve? Or is it claiming a direct mechanical lift that the drawing does not show?
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Before You Answer
ā¢ Identify exactly which part is the pilot valve (small valve) and which is the main valve (large flow area) and how chambers I, II, and III are related.
ā¢ Verify whether A is held on its seat by spring force, pressure difference, or both; and whether C is moved by pressure imbalance rather than direct linkage.
ā¢ Check the path through restriction H and any small passages: does water normally flow from II to I, and from I to III only when a pilot opens? This will help you reject choices that get the direction of flow or the sequence of forces wrong.