The weighted ram is a type of accumulator that uses which mechanism?

• A. A weight to provide the load
• B. A gas charge
• C. A bladder
• D. A piston

Answer: (A)

The main idea here is energy storage in a hydraulic system by applying a preload on the fluid. A weighted ram uses a heavy mass resting on a ram to provide that preload via gravity. This weight pushes on the ram, creating a constant hydraulic load, so energy is stored in the form of hydraulic pressure and, associated with the weight, gravitational potential energy. When the system requires energy, the pressure moves the ram and the stored energy is delivered to do work, without relying on gas springs, a flexible bladder, or a separate piston with gas backing.

Gas-charged, bladder-type, and piston-backed accumulators all store energy using compressible gas or a flexible membrane, or rely on a gas behind a piston. The weighted ram distinguishes itself by using a weight to provide the preload, rather than a gas or bladder mechanism.