Hydraulics and Pneumatics (Fluid Power) Flashcards

Which principle states that pressure applied to a confined fluid is transmitted equally in all directions?

Answer: Pascal's Law

Pascal's Law says that pressure applied to an enclosed fluid is transmitted undiminished to every part of the fluid and to the container walls. This is the basic principle behind all hydraulic systems.

A hydraulic system operates at 1,000 psi. How much force does a cylinder with a piston area of 4 square inches produce?

Answer: 4,000 lb

Force = Pressure × Area. 1,000 psi × 4 sq in = 4,000 lb of force.

What is the main purpose of a pressure relief valve in a hydraulic circuit?

Answer: To limit the maximum system pressure

A relief valve opens and sends fluid back to the tank when system pressure reaches its set point. This protects the pump, hoses and components from over-pressurization.

Which hydraulic component converts fluid energy into straight-line (linear) motion?

Answer: Hydraulic cylinder

A hydraulic cylinder is a linear actuator: fluid pressure pushes on its piston and extends or retracts the rod. A hydraulic motor produces rotary motion, and a pump produces flow.

In a pneumatic system, what do the three parts of an FRL unit stand for?

Answer: Filter, Regulator, Lubricator

An FRL unit conditions compressed air before it reaches tools and actuators. The filter removes moisture and particles, the regulator sets the working pressure, and the lubricator adds a fine oil mist.

A hydraulic pump makes a loud rattling, 'marbles-in-a-can' noise. The suction strainer is badly clogged. What is the most likely problem?

Answer: Cavitation

A restricted inlet starves the pump, so low pressure at the suction side forms vapor bubbles. When those bubbles collapse they make the rattling noise and erode the pump. This is cavitation.