Hydraulic Systems and Schematics 1 Flashcards
6 cards from real Millwright Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Hydraulic Systems and Schematics 1 flashcards as text
What is the purpose of a pressure relief valve in a hydraulic circuit?
Answer: To limit maximum system pressure and protect components from overload
A pressure relief valve opens when system pressure reaches a preset limit, diverting excess fluid back to the reservoir. This prevents damage to pumps, cylinders, valves, and hoses from overpressure conditions.
On a hydraulic schematic, what does a circle with an arrow pointing inward represent?
Answer: A hydraulic pump
In ISO hydraulic schematic symbols, a circle with an arrow pointing inward (toward the center) represents a hydraulic pump, indicating energy input into the fluid. An outward arrow denotes a hydraulic motor.
Which type of hydraulic pump is best suited for high-pressure, variable-flow applications?
Answer: Axial piston pump
Axial piston pumps can operate at very high pressures and allow displacement to be varied by adjusting the swashplate angle, making them ideal for demanding variable-flow, high-pressure systems.
A hydraulic system produces a knocking or banging noise during operation. What condition does this most likely indicate?
Answer: Cavitation caused by inadequate fluid supply to the pump inlet
Cavitation occurs when the pump cannot receive enough fluid, causing vapor bubbles to form and then violently collapse. This produces a characteristic knocking noise and can rapidly damage pump internals.
What is the function of a counterbalance valve in a hydraulic circuit?
Answer: To maintain back pressure on a load-holding cylinder and prevent it from drifting or dropping
A counterbalance valve is set above the load-induced pressure and placed on the outlet port of a cylinder. It prevents uncontrolled descent of suspended loads by requiring positive pilot pressure before it opens.
When reading a hydraulic schematic, a dashed line connecting two components typically indicates what type of connection?
Answer: A drain or pilot line
In standard hydraulic schematic notation, solid lines represent main pressure or return lines, while dashed lines represent pilot lines or drain lines, which carry low-pressure control or leakoff fluid.