introduction to fluid power by mike pierno. pascal’s law, simply stated, says this: pressure...
TRANSCRIPT
Pascal’s Law, simply stated, says this:
Pressure applied on a confined fluid is transmitted undiminished in all directions, and acts with equal force on equal areas and at right angles to them.
F = P x A
Pascal’s Law
HOW PRESSURE IS CREATED
Pressure results whenever there is a resistance to
fluid flow or to a force which attempts to make the
fluid flow. The tendency to cause flow (or the push)
may be supplied by a mechanical pump, compressor,
or may be caused simply by the weight of the fluid.
Force is Proportional to Pressure and Area
These Pressure, Force and Area relationships are sometimes illustrated as shown below to aid in remembering the equations.
F = P x A
P = F / A
A = F / P
When a cylinder is used to clamp or press, its output force can be computed as follows:
F = P x A
Again:
P is Pressure (PSI (Bar) (Pascals))
F is Force (pounds (newtons))
A is Area (Square inches (Square meters)
P A
F
Parallel Flow PathsList the order in which the cylinders will extend, and calculate the pressure needed to lift the load for each.
A B C
4” bore 2” bore 6” bore
Sequence
1st
2nd
3rd
PSICyl.
24,000 lbs. 24,000 lbs. 24,000 lbs.
Bernoulli’s PrincipleBernoulli’s Principle states that if the flow rate is constant, the sum of the kinetic ands pressure energy must be constant. Therefore, if the kinetic energy decreases, it must result in an increased pressure. Likewise, when the cross-sectional area of the flow path decreases, the kinetic energy (velocity) produces a corresponding decrease in pressure.