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Fluid power formulas

Torque and horsepower relations:

T = HP x 5252 ÷ RPM
HP = T x RPM ÷ 5252
RPM = HP x 5252 ÷ T

Torque values are in foot-pounds.
Hydraulic (fluid power) horsepower:

HP = PSI x GPM ÷ 1714

PSI is gauge pressure in pounds per square inch, GPM is oil flow in gallons per minute.
Velocity of oil flow in pipe:

V = GPM x 0.3208 ÷ A

V 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 behaviour of gases:

T1V2 = T2V1, or T1P2 = T2P1

T1, P1 and V1 are initial temperature, pressure and volume, and T2, P2 and V2 are final conditions.
Boyle's Law for behaviour of gases:

P1,V1 = P2,V2

P1, V1 are initial pressure and volume; P2 and V2 are final conditions.
Heat equivalent of fluid power:

BTU per hour = PSI x GPM x 1-1/2

Burst pressure of pipe or tubing:

P = 2t x S ÷ 0

P is burst pressure in PSI, t is wall thickness, in inches; S is tensile strength of material in PSI; O is outside diameter, in inches.
0 est le diamètre extérieur en pouces.
Thrust or force of any cylinder:

T = A x PSI

T is thrust or force, in pounds, A is piston area in square inches, PSI is gauge pressure.
Hydraulic Cylinder Piston travel speed:

S = CIM ÷ A

S is piston travel speed, inches per minute, CIM is oil flow into cylinder, cubic inches per minute, A is piston area in square inches.
Pressure loss per foot of pipe:

P = V x Q ÷ 18,300 D4

P is pressure loss in PSI per foot of pipe length.
V is SSU viscosity at operating temperature.
Q is GPM flow. D is inside diameter of pipe in inches
Force for piercing or shearing sheet metal:

F = P x T x PSI

F  is force required, in pounds, P is perimeter around area to be sheared, in inches, T is sheet thickness in inches; PSI is the sheer strength rating of the material in pounds per square inch.
Heat radiating capacity of a steel reservoir:

HP = 0.001 x A x TD

HP is the power radiating capacity expressed in horsepower; A is surface area, in square feet; TD is temperature difference in °F between oil and surrounding air.
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, in pounds, A is the least angle, in degrees, between cylinder axis and load direction..

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