nonhydraulic

Nonhydraulic is an adjective used to describe systems, mechanisms, or processes that do not rely on fluids under pressure to transmit force or energy. In engineering, it is often used to distinguish such approaches from hydraulic systems, which use incompressible liquids (typically oil or water) in cylinders, pumps, and valves to multiply force and control motion.

As a broad category, nonhydraulic encompasses mechanical, pneumatic, and electrical actuation. Mechanical methods use gears, levers, cams, or rack-and-pinion linkages. Pneumatic systems use compressed gas to produce motion, while electric actuators convert electrical energy directly into motion or torque. In practice, many machines combine nonhydraulic and hydraulic elements, selecting the approach for reliability, response, and maintenance considerations.

Advantages of nonhydraulic systems include reduced leakage risk, avoidance of fluid contamination, and often simpler maintenance. Tradeoffs include lower force density (especially for pneumatic systems), energy inefficiencies due to compression, and potential speed limitations compared with hydraulic solutions in some applications.

In energy industry usage, "nonhydraulic fracturing" refers to methods that do not inject pressurized fluids to fracture rock, such as mechanical or explosive techniques; hydraulic fracturing remains the most common approach for stimulation in oil and gas extraction. The term "nonhydraulic" thus serves as a contrast in both mechanical design and method selection contexts.