Hydraulic and Pneumatic Knowledge
Fluid Power Equipment
The following are equations for Fluid Power applications, Fluid Velocity on a pipe, Charles Law, and more.
Torque and Horsepower Relations:
T=(HP x 5252)/RPM HP= (T x RPM)/5252 RPM = (HP x 5252)/T
Torque is FTLBS
Hydraulic Fluid Power horsepower:
V = (GPM x PSI)/ 1714
PSI is gauge pressure in in pounds per square inch GPM is oil flow in Gallons per minute.
Fluid Power Velocity of oil flow in pipe:
V =(GPM x .3208) /A
Z is oil velocity in feet per second, GPM is flow in gallons per minute, A is inside area of pipe in square inches.
Charles Law for behavior of gases:
T_{1}V_{2}  T_{2}V_{1} or T_{1}P_{2 }= T_{2}P_{1}
T_{1}, P_{1} and V_{1} are initial temperature, pressure, and volume, and T_{2}, P_{2}, and V_{2}
are final conditions
Boyle's Law for behavior of gasses:
P_{1}V_{1} = P_{2}V_{2}
P_{1} and V_{1} are initial pressure and volume; P_{2} and V_{2} are final conditions.
Heat equivalent of fluid power:
BTU per hour = PSI x GPM x 1.5
Hydraulic cylinder piston travel speed:
S = CIM / A
S is thrust of force, in pounds A is piston net area in square inches PSI is gauge pressure. CIM is oil flow into cylinder, cubic inches
per minute
Side load on pump or motor shaft:
F = (HP x 63024) / (RPM x R)
F is the side load, in pounds against shaft R is the pitch radius, in inches, of sheave on pump shaft HP is the driving power applied
to shaft
Effective force of a cylinder working at an angle to direction of the load travel:
F = T x sin(A)
T is the total cylinder force, in pounds F is the part of the force which is effective A is the least angle, in degrees between cylinder
axis and load direction
Heat radiating capacity of a steel reservoir:
HP = .001 x A x TD
Where:
HP = Power radiating capacity expressed in horsepower A
= Surface area, in square feet TD = Temperature difference in deg. F
between oil and surrounding air.
Burst pressure of pipe or tubing:
P = (2t x S) / O
P is burst pressure in PSI t is wall thickness, in inches S is tensile strength of material in PSI O is outside diameter, inches
Relationship between displacement and torque of a hydraulic motor:
T = (PSI x D)/ (24 x
3.14157)
T is torque in foot  lbs D is displacement in cubic inches per revolution PSI is pressure difference across motor
