How is pressure commonly expressed in hydraulic and pneumatic systems?

Pressure in hydraulic and pneumatic systems is commonly expressed in pounds per square inch (psi). This unit is widely used in the United States and is particularly relevant for applications involving the force applied per unit area, which is crucial for understanding how these systems operate.

Hydraulic systems, for instance, rely on the transmission of pressure through incompressible fluids to transmit power. In these systems, the use of psi allows mechanics and engineers to calculate force and determine the capacity of the components (such as cylinders and pumps) effectively. Similarly, in pneumatic systems, which use gases under pressure, psi provides a consistent framework for measuring and conveying the necessary pressure levels.

While other units like kilograms per square centimeter, newtons per square meter, and atmospheres can also express pressure, they are less common in this specific context. Kilograms per square centimeter is more often used in certain scientific and engineering applications but not typically in everyday hydraulic and pneumatic system measurements, especially in the U.S. Newtons per square meter, known as pascals, is the SI unit of pressure but is generally seen more in other fields like physics. Atmospheres might be used in specific applications but is not the standard unit for hydraulic and pneumatic systems in practical maintenance and operation contexts.