š Key Concepts
ā¢ Trace how the exhaust dump valve (at D) is linked mechanically to the piston and lever assembly above it.
ā¢ Look at what physical signal (vacuum, pressure, spring force, or bellows motion) ultimately moves the piston that pulls the dump valve closed.
ā¢ Note the functions of points A, F, G, and I in the diagram: supply pressure, spring, vacuum line, and bellows.
š Think About
ā¢ Follow the flow path from the condenser/gland exhaust side back to the actuator: when the turbine is on vacuum and ready to send gland steam to the condenser, what change in the system should make the dump valve close?
ā¢ Ask yourself: does the dump valve piston respond directly to steam pressure in the manifold, to vacuum from the condenser, or to motion transmitted from another sensing element such as a bellows or spring?
ā¢ Which component is the sensing element and which one is the force source for actually moving the piston that shuts the dump valve?
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Before You Answer
ā¢ Identify which label marks the piston that operates the exhaust dump valve and then trace what is connected to its upper side mechanically or hydraulically.
ā¢ Verify which of the four options is the initial signal that changes when condenser vacuum is established and is used by the regulator to end atmospheric dumping.
ā¢ Confirm whether the component at I directly pushes the piston, or whether it merely reacts to the condition at G and transmits motion through the pivot rods and lever assembly.