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Examoogle • User • info@examoogle.com • EE-2024-8821
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Hydraulic amplifier consists of
Pilot valve
Main piston
Both a and b
Steam valve
Both a and b
Quick Summary: A hydraulic amplifier is a feedback-controlled mechanical device used in turbine governing systems to multiply a low-power input signal into a high-force output. It consists of a pilot valve that controls fluid flow to a power piston (main piston), which in turn executes the mechanical work required to adjust the turbine's steam or water admission valves.
A hydraulic amplifier is a feedback-controlled mechanical device used in turbine governing systems to multiply a low-power input signal into a high-force output. It consists of a pilot valve that controls fluid flow to a power piston (main piston), which in turn executes the mechanical work required to adjust the turbine's steam or water admission valves.
Fout=P×A
dindout=Kamp
The pilot valve acts as a small, sensitive actuator that regulates high-pressure hydraulic oil flow to either side of the main piston. When the pilot valve moves, it opens a port allowing oil to push the main piston. As the main piston moves, it carries a mechanical linkage (feedback lever) that restores the pilot valve to its neutral position once the target displacement is achieved.
Pilot valves provide the amplification mechanism by acting as high-gain fluid switches.
The main piston provides the high-force output needed to move heavy gate valves or steam nozzles.
Feedback mechanisms are essential to prevent over-travel of the main piston.
Commonly used in speed governing systems of hydroelectric and thermal power plants.
High power-to-weight ratio for the output signal
Extreme reliability in heavy industrial environments
Precise control over large mechanical displacements
Requires complex maintenance of hydraulic seals and fluid quality
Risk of fluid leakage posing safety or environmental concerns
Turbine speed governing systems
Heavy-duty power plant steam valves
Automotive power steering systems
The pilot valve is typically connected to the speed sensing mechanism (e.g., flyball governor).
If the main piston were absent, the small pilot valve could not provide enough force to move the turbine steam valve, which is under significant pressure.
C is correct — The hydraulic amplifier system utilizes both a sensitive pilot valve for signal detection and a main piston for high-power mechanical actuation.
Always remember that in power generation control, 'pilot' devices are for sensing/low-signal, while 'main' or 'power' components are for high-energy mechanical execution.