Hydraulic press: primary function and comparison with related devices In fluid power systems, a hydraulic press is a device used to lift or compress a much larger load by applying a comparatively small force through pressure transmission. Which statement best describes its principal use?

Introduction / Context:
A hydraulic press is a classic application of Pascal's law. It uses two cylinders with different areas connected by a fluid. A small input force on the small-area piston creates the same pressure throughout the fluid, which acts on the large-area piston to generate a much larger output force. This question checks whether you can distinguish a press from other hydraulic units such as accumulators and intensifiers.

Given Data / Assumptions:

• Incompressible fluid and negligible leakage.
• Two pistons with areas A_small and A_large, hydraulically connected.
• Quasi-static operation where dynamic losses are minor.

Concept / Approach:
By Pascal's law, the pressure p applied on the small piston equals the pressure under the large piston. Therefore F_out / A_large = F_in / A_small, so F_out = F_in * (A_large / A_small). This gives a mechanical advantage equal to the area ratio, enabling a small effort to lift or press a heavy load.

Step-by-Step Solution:
Apply F_in on the small piston ⇒ p = F_in / A_small.The same p acts on the large piston ⇒ F_out = p * A_large.Therefore F_out = F_in * (A_large / A_small).Because A_large » A_small, a small force lifts a large load, which defines a hydraulic press.

Verification / Alternative check:
Energy balance (ignoring losses): F_in * s_in ≈ F_out * s_out. The larger force is achieved at the expense of reduced displacement, consistent with the area ratio.

Why Other Options Are Wrong:
Option (a) describes a hydraulic accumulator (energy storage). Option (b) describes a hydraulic intensifier (pressure multiplication). Option (d) groups different devices and is therefore incorrect for a press's principal use. Option (e) is a measuring device, not a press.

Common Pitfalls:
Confusing energy storage (accumulator) and pressure multiplication (intensifier) with force multiplication via area ratio (press). Mixing up force advantage with pressure increase.

Final Answer:
to lift a larger load by applying a comparatively much smaller force (hydraulic press)