Hydraulic Systems Flashcards

What does a hydraulic accumulator primarily store?

Answer: Hydraulic fluid under pressure

A hydraulic accumulator stores hydraulic fluid under pressure to supplement pump flow or absorb pressure shocks.

Which type of hydraulic pump is considered a fixed-displacement pump?

Answer: Gear pump

Gear pumps deliver a fixed volume of fluid per revolution and cannot vary their displacement.

A hydraulic system is operating at 3,000 PSI with a cylinder bore of 2 inches. What is the approximate force output?

Answer: 9,425 lbf

Force = Pressure × Area; Area = π × r² = π × 1² ≈ 3.14 in²; Force = 3,000 × 3.14 ≈ 9,425 lbf.

What is the purpose of a hydraulic flow control valve?

Answer: Regulate the speed of actuators

Flow control valves regulate the rate of fluid flow to control the speed of hydraulic actuators.

Which hydraulic seal material is most resistant to petroleum-based hydraulic fluids?

Answer: Nitrile (Buna-N)

Nitrile rubber is the standard seal material for petroleum-based hydraulic systems due to its excellent oil resistance.

What condition is indicated when a hydraulic pump produces a whining or cavitation noise?

Answer: Insufficient fluid supply to the pump inlet

Cavitation occurs when the pump inlet is starved of fluid, causing vapor bubbles to form and collapse violently.

In a hydraulic schematic, what symbol represents a pressure relief valve?

Answer: An arrow pointing into a line with a spring symbol

Pressure relief valves are shown with a normally-closed arrow symbol with a spring, indicating they open at a set pressure.