FLUID POWER FORMULAS

BASIC· FORMULAS

FORMULA FOR:

WORD FORMULA: lETTER FORMULA:

FLUID PRESSURE

PRESSURE

_ FORCE (fXJUnds) P

F . F

In P/JUnds/Square Inch

U/IIT AREA (Square Inches)

=AOf pSI = A

FLUID FlOW RATE

=VOLUME (Gallons)=Y..

.-

FLaN RATE

0

In Gal/ollS/Minule

UNIT TIME (Minute)

T

FLUID POWER IN HORSEPOWER

HORSEPOWER

= PRESSURE (PSI) x FLOW (GPM) HP =~

1714

1714

FLUID FORMULAS

VELOCITY THROUGH PIPING

VELOCITY

= .3208 x flOW RATE THROUGH 1.0. (GPM) V

= .32080

tn Feet/Second ~

INTERNAl AREA (Square Inches)

A

COMPRESSIBILITY OF Oil

ADDITIONAL

PRESSURE (psi) x VOLUME OF Oil UNDER PRESSURE pv •• Approximately

=VA= 25O,ooolapprox.) \/2% Per 1000 psi

In Additional Required Or7 To Reach Pressure

VOLUME

250,000 lapprox.)

COMPRESSIBILITY OF A FLUID

1

-

CIP) = --1-

COMPRESSIBILITY =

BULK MODULUS OF THE FLUID 8M

SPECIFIC GRAVITY OF A FLUID

SPECIAC GRAVITY

=

WEIGHT OF ONE CUBIC FOOT OF flUID

SG = _W_

WEJGHT OF ONE CUBIC FOOT OF WATER

62.4283

VALVE Ie. ) FLOW FACTOR

VALVE FACTOR(e., )

_ flOW RATE (GPM) x \JSPECIFIC GRAVITY

c., =a VSG

VPRESSURE DROP(PS!)

IfiP

FOR VISCOSITIES OF 32 TO 100 SAYBOlT UNIVERSAl SECONDS:

VISCOSITY IN CENnSTOKES CEIITISTOKES

= .2253xSUS-~ CS = .2253 SUS _ 194.4

SUS

SUS

FOR VISCOSITIES OF 100 TO 240 SAYBOLT UNIVERSAl SECONDS:

VISCOSITY IN CENTISTOKES CElITISTOKES

=.2193 x SUS _ 134.6 c.s = .2193 SUS _ 134.6

SUS

SUS

FOR VISCOSITIES GREATERTHAN 240 SAYBOLT UNIVERSAL SECONDS:

VISCOSITY IN CENTISTOKES CENTISTOKES

=2!!.§. c.s =SUS

4.635

4.635

NOTE: SAYBOlT UNIVERSAL SECOIIDS IS OFTEN ABBREVIATED AS SSU. SEE PAGE120 FOR ADDITlONAl VISCOSITY INFORMATION. PUMP FORMULAS

PUMP OUTlET FLOW

flOW

= RPM x PUMP DISPlACEMENT (Cu. In.lRev.) 0

=~

In Gallons/Minute

231

231

PUMP INPUT POWER

HORSEPOWERINPUT

= FlO'N RATEOUTPUT (GFM) x PRESSURE (psi) HP =_O_P _ or GPM x psi

In HOrsepD!!fr Required

1714 x EFFICIE/ICY (Ov-r:raU)

m1714 Elf 1714E1f

PUMP EFACIENCY

OVERAll EFACIENCY

= OUTPUT HORSEPOWER x 100 Elfa,

=!!k x 100

OVERALL IN PERCENT

lllPUT HORSEPO'NER

HP"

OVERAll EFACIENCY

=VOLUMETRIC Elf. x MECHANICAL Elf Elf",

=EIf,'CL x EIf.EOt

PUMP EffiCIENCY

VOLUMETRIC EFFICIENCY

= ACTUAL flOW R.I,TEOUTPUT (GPMJ x 100 EIf~.

= ~ x 100

VOLUMETRIC IN PERCENT

THEORETICAl FLOW RATEOUTPUT {GPMJ

O",ro

PUMP EFACIENCY

MECHANICAL EFFICIENCY

THEORETICAl TOROUE TO ORIVE

x 100 EIf.EO! = TTHED X100

=MECHANICAL IN PERCENT

ACTUAl TOROUETO DRIVE

TACT.

PUMP LIFE B HOURS OF BEARING LIFE =RATED LIFE HOURS x RATEDSPEED (RPM) x ( RATEDPRESSURE (PSI) \3

8'0 = RATEDHAS. x RPM, x f-;:i J

B,o BEARING LIft

" NEVI SPEED {RPM} flEW PRESSURE (PSI) J

RPMM PH

ACTUATOR FORMULAS

FORMULA FOR:

WORD FORMULA lETTER FORMULA

CYLINDER AREA

AREA

= r XRADIUS> (Inches) A=712

In Squiire Inches

AREA

= .!:.x DIAMETER' (Inches) A=r[» orA = .78S[»

4

4

CYLINOER FORCE

FORCE

=PRESSURE (psi) x NET AREA (Square Inct.es) F =psixAorF=PA

In P/JUnds, Push or Pull