Introduction to Hydraulics 2

Which material is most suitable for low-pressure hydraulic systems due to its lightweight and chemical resistance?

• Steel

• Copper/Brass

• Aluminum

• Plastic

When sizing hydraulic pipes, which of the following flow velocities is recommended for pressure lines to prevent overheating?

• 0.6-1.5 m/sec

• 2-3 m/sec

• 4-6 m/sec

• 7-8 m/sec

The pressure loss equation in a straight pipe includes a friction factor (f). Which of the following factors does NOT directly influence this friction factor?

• Pipe material

• Pipe diameter

• Fluid viscosity

• Pipe length

In a hydraulic system, what is the primary purpose of a pressure relief valve?

• Maintain constant flow speed

• Limit maximum pressure to protect system components

• Control the direction of fluid flow

• Allow fluid to bypass when pressure is low

Which type of fitting is most likely to require thread sealant due to its common usage in North American hydraulic systems?

• BSP (British Standard Pipe)

• JIC flare fitting

• NPT (National Pipe Tapered)

• ORFS (O-Ring Face Seal)

When selecting a hydraulic motor for a high torque, low-speed application, which type is generally recommended?

• Gear motor

• Radial piston motor

• Piston motor

• High-speed vane motor

What hydraulic component is used to: a) Direct the flow of fluid within a circuit, b) Start/stop or change the flow direction, c) Control the actuator's speed?

• Pressure control valve

• Flow control valve

• Directional control valve

• Check valve

In a four-way, three-position valve, what is the function of the center position called 'Open center'?

• All ports are blocked

• All ports are connected to tank for free flow

• Pump is unloaded

• Pump pressure is diverted directly to load

Which of the following statements correctly describes a double-acting hydraulic cylinder?

• It can only extend using fluid pressure, retraction is spring-driven.

• It uses fluid pressure on one side only and relies on gravity for retraction.

• It uses hydraulic fluid on both sides of the piston for extension and retraction.

• It can only retract using external force.

What is the main advantage of a vane hydraulic motor compared to a gear motor?

• Higher efficiency at low speeds

• Smoother operation and better velocity control

• Higher torque at low speeds

• Less sensitivity to contamination