Blaise Pascal formulated this basic law in the mid-17th century. His law states that pressure in a confined fluid is transmitted undiminished in every direction and acts with equal force on equal areas and at right angles to container walls. Hydraulic brakes, lifts, presses, syringe pistons, etc. work on the principle of Pascal’s law.
According to Pascal’s law, inside the pipes of a confined system pressure is uniform at all points. Mathematically,
From the above expression, P1 = P2, therefore F2 is greater than F1 because A2 is greater than A1. This means that, in order to obtain a greater output force, it is enough to have suitably sized surfaces available.
Flow and Flow Rate
The volume of a substance passing a point per unit time is called flow and the volume of water, a pump or a compressor can move during a given amount of time is called, “flow rate.”
■ Volumetric Flow Rate
It is the volume of the fluid flowing through a cross section per unit time. Air related flows are usually expressed in cubic feet per minute (CFM) and for liquid-based fluids, they are expressed as liters or gallons per minute (LPM or GPM) or cubic meters per second, etc.
Volumetric Flow Rate =Area × Velocity
■ Mass Flow Rate
Volumetric flow rate times density, i.e., pounds per hour or kilograms per minute.
Mass Flow Rate=Area × Velocity × Density
