FLUID POWER FORMULAS
WEIGHT
OF. ONEFCUBIC
flUID
. - FOOT
- _ OF
F
THEORETICAl
TOROUE
TO
ORIVE GRAVITY
lllPUT
HORSEPO'NER
FORCE
(fXJUnds)
231
ACTUAl
TOROUE
TO
DRIVE
flOW
(GPM)
\JSPECIFIC
INTERNAl
AREA
(Square
Inches){GPMJ
UNIT
TIME
(Minute)
AREA
(Square
Inches)
THEORETICAl
FLOW
RATE
OUTPUT
"VOLUME
NEVI
SPEED
{RPM}
250,000
lapprox.)
(PSI)
FLOW
(GPM)
.3208
flOW
RATE
THROUGH
1.0.
(GPM)
1714
EFFICIE/ICY
(Ov-r:raU)
RPM
xRATE
DISPlACEMENT
(Cu.
In.lRev.)
=
1714 U/IIT
FlO'N
RATE
OUTPUT
(GFM)
x OF
PRESSURE
0
==~ .32080
1xpSI
TElf
231
AOf
4
8M
ADDITIONAL
A62.4283
SUS
4.635
=!!k~
100
OUTPUT
HORSEPOWER
100
.2253xSUS-~
SUS
pv
••
Approximately
=
.2193
VOLUMETRIC
xx PUMP
SUS
flOW
Elf.
_
xxR.I,TEOUTPUT
MECHANICAL
(GPMJ
Elf
x(psi)
100
A
1714
712
1714E1f
m
HP"
(psi)
VOLUME
Oil
UNDER
PRESSURE
= 2!!.§.
PRESSURE
.!:.x
XACTUAL
DIAMETER'
RADIUS>
(psi)
(Inches)
xxx134.6
(Inches)
NET
(Square
Inct.es)
rPRESSURE
Elf",
F
=psixAorF=PA
EIf,'CL xx OF
EIf.EOt
TACT.
O",ro
A
EIf.EO!
=xAREA
TTHED
r[»
orASUS
=_ _.78S[»
VOLUME
FORCE
PRESSURE
P
V
AREA
SPECIAC
GRAVITY
BULK MODULUS
THE FLUID
=~(Gallons)
CElITISTOKES
OVERAll
EFACIENCY
SG
=
_W_
CEIITISTOKES
CS
=
.2253
0c.s
VA=
25O,ooolapprox.)
_O_P
or194.4
GPM
\/2%
x psi
Per 1000 psi
x 100 CIP) = VELOCITY
HORSEPOWER
MECHANICAL
EFFICIENCY
INPUT
HP
flOW
VOLUMETRIC
EFFICIENCY
.2193
134.6
CENTISTOKES
SUS
VALVE
--1- FACTOR
(e., X
) 100
Elfa,
EIf~.
c.,
= a VSG
AREA
=
=
WORD FORMULA
FORMULA:
B
HOURS OF BEARING LIFE
flEW PRESSURE (PSI)
=A
FORMULA:
===Y..
lETTER FORMULA
= IfiP= =
RPMM
PH
=
BASIC·
FORMULAS
8'0
=
RATEDHAS.
x
RPM,
x
= RATED PUMP
LIFE HOURS x RATEDSPEED (RPM) x ( RATEDPRESSUREf-;:i
(PSI) J \
FORMULAS
J
3
FLUID POWER FORMULAS
ACTUATOR FORMULAS
. FORMULA
-
CONTINUED
WORD FORMULA
FOR:
CYLINDER VELOCITY or SPEED
LETTER FORMULA
=
VELOCITY
CYLINDER VOLUME CAPACITY
=
VOLUME
x
x
231
12
In FeetJSerond
x
60
flOW RATE
r X RADiUS'
(Inches)
231
In Gallons of Fluid
=
IIET AREA
(GP!.1)
=
y
x STROKE (Inches)
x
STROKE (Inches)
RATE
flOW
_
R~TE
12
x
x
60
VELOCITY (FeevSec)
flUID
MOTOR TOROUE
=
TOROUE
x
PRESSURE (psi)
o
= 720vA
231
231
NET AREA (Square InCl1es)
or
Length 01 Slroke
0 = 3.117yA
F.M. DISPLACEMENT (Cu. In.lRev.)
2r
In Inch Pounds
flUID
x
I=
=~
231
In Gallons Per Minute
A
v
231
CYlINDER flOW
.32080
I
= rf'
v
221
(Slrwe Inches)
=
2310 ory
72M
IIET AREA (Square Inches)
MOTOR TOROUE/100 psi
=
HORSEPOWER
RPM
=
FLOW RATE (GPM)
=
TOROUE/loo psi -
In Inch Pounds
FLUID MOTOR SPEED
FLUID MOTOR POWER
HORSEPOWER
63025
x
PRESSURE (psi)
RPM
x 36.77
n
HP
T,=
F.M. DISPLACEMENT (Cu. Inches/RevotuDon)
.0628
_
SPEED
In RevoIulions/Minule
x
T
= 63025 HP
n
T
=
--
36.770P or T = 36.770psi
n
n
=-d-63025
d
=
.0628
Tn
2310
231 flOW RATE (GPM)
-
F.M. DISPLACEMENT (Cu. Inches/Revolution)
=
TORQUE OUTPUT (Inch Pounds)
63025
In Horsepower Output
THERMAL
x
RPM
FORMULAS
NOTE: ONE BRITISH THERMAL UNIT (BTU) IS THE AMOUNT OF HEAT REOUIREDTO RAISE THE TEMPERATURE OF ONE POUND OF WATER OIlE OEGREEF.AHRENHBT.ONE HORSEPOWER = 2545 BTU/HR.
RESERVOIR COOUNG CAPACITY
HEAT (BTU/HR)
=
2
x
TEMPERATURE OJFFERENCEBffi'/EEN
RESERVOIRWAlLS AND AIR (oF)
x AREA OF RESERVOIR(SO. Ft)
BASED
ON ADEQUATE
HEAT IN HYDRAULIC OIL (approx.)
DUE TO SYSTEM
BTUIHR
=
2.0
BTU/HR
=
0
x
210
x
AT
BTU/HR
=
0
x
500
x
AT
x
x
AT
A
AIR CIRCULATION
INEFFICIENCY
(SG
=
I
.89
HEAT (BTU/HR)
=
Fl(J.'I1WE
(GPM)
x
210
x
TEMPERATURE DIFFERENCE(oF)
=
FLOW RATE (GPAt)
x
500
x
TEMPERATURE DIFFERENCE(OF)
-
.92)
HEAT IN FRESH WATER (approx.)
tHEAT
(BTU/HR)
PRESSURE
DROP FORMULAS
NOTE: SEE PAGES 79 THROUGH 84 FOR INFORMATION
ACCUMULATOR·
FORMULAS
NOTE: SEE PAGES 130 AND 131 FORADDITIONAL INFORMATION
FORMULA
FOR:
PRESSURE OR VOLUME .
w/Constant
PRESSURE
"r
Where UP"
=
psia(ABSOLUTf}
x
psig (GAUGE PRESSURE)
lETTER
WORD FORMULA:
ORlGIIIAL PRESSURE
=
ORIGINAL VOLUME
=. FIfIAL
14.7 psi
FORMULA:
FINAL VOLUME
P, V,
=
X ORIG. TEMPERATURE
P, T,
= P, T, lsochoric
ORIGINAL TEMPERATURE
V, T,
=
x
PRESSURE
+
P, V,
lsothermic
(Temperature)
OR TEMPERATURE
. ORIGIIW: PRESSURE
x FIIJAi. m,IPERATURE
;; FlllAlPRESSURE
w/ Constant "V" (Volume)
VOLUME
OR TEMPERATURE
ORIGII/AL VOLUME X AI/AL TEI,IPERATURE
= FINAL VOLUME
x
V, T, Isobaric
w/Constant "P" (Pressure)
PRESSURE
OR VOLUME
ORIGINAL PRESSURE
x ORIGIIIAL VOLUME" ...= FINAL PRESSURE x FINAL VOLUME"
w/Tempetalure Change Due
-
To Heat of Compression
FINAL TEMP.
TEMP.
ORIG.
U.S.
1
.037037
.0005787
.00002143
i,48052
28.317
.004329
.016384
146.656
1728
1.119825
.0160184
.004951
201.974
764.56
.001308
1.20032
.0353145
.160459
.264170
1.133681
4.54374
13.78543
27
.453592
2277.274
31
27.6798
61.0234
.0005929
.0059429
Liters
~~
.>
.....•.•.•...
i;,;
ORIG.
FIlIAL VOLUME\
VOLUMFj
l'"
",:,eINAL
ORIS. PRESSURE
PRESSURE
Gar:u.1S
VOLUME&CAPACITY
EQUIVALENTS
Water at Max. Oensity
39.2° F 4° C
~rams
. -\y.;;-.
.0036065
6.23210
168.266
I
·of-Water
.0163872
.0361275
62.4283
1685.56
28.3170
764.559
.220083
2.20462
1
.833111
8.34545
3.78543
1
.0998281
10.0172
1
4.54373
.453593
To Convert
cms
Into
...
0.06102
0.001
0.02832
Liters
28.317
.0036065
feet
meters
.OF. Cms/sec
31.5
7.48052
448,83
0.01639
35,31
14.50
6.23210
7.481
28.32
264.2
0.5080
.00003521
.000001
.0002642
.0005787
.00001639
.004329
16.39
Fahrenheit
Gallons/min
Cu
cms/min
Gallons
Liters/min
inches
10,200
28,320
28,317
61,023
Pounds/sq
in...liquid)
Imperial
1,728
1,000,000
1,000
gallons
Multiply
by
Gallons
Kgs/sq
=9.5)
(tmeter
(U.S.
32)/1.8
tDegree
DC
Celsius
(COx
+32
Gallons/min
Liters
Liters/min
FeeVmin
Imperial
Kilograms/sq
Pascal
Pounds/sq
U.S,
U.S.
gallons
(Pa)
gallons
inch
cm
meter
To Convert
Into
...
277.274
4.54374
0.0353145
61.0234
0.001
3785
231
,160459
,00009807
.220083
1000
.069
.133681
.3785
Bar
Gallons/min
Bars
cms
meters
703.1
3.785
0.264170
3,785
.1337
1,20032
14.22
,001422
.035
.264
,00001
.000145
.83267
feet
Meters/min
Liters
Cu
feeVmin
inches
cm
0.3048
Liters/min
cms/min
2,048
3,785.412
6,895
1,000
Pounds/sq
Kgs/sq
meter
Multiply
byftin...liquid)
U.S.
gallons
Gallons
Imperial
(U.S.
gallons
Pascal
(Pa)
TABLE
6-E. CONVERSION
BETWEEN ENGLISH
UNITS AND SI UNITS
The "SI" (International
Standards) units shown below are adopted for use by the International
munity, and should be used on documents prepared for international circulation.
Conversion
Quantity
SI Unit for Fluid Power
"Customary"
Length .
Pressure*
Pressure**
Flow***
Flowt
Force
Mass .
Time ...
Volume*.**.
Temperature
Torque
.
Power
Shaft Speed
Frequency .
Displacement
Kinematic viscosity
Velocity.
millimeter (mm) .
bar (bar, g or bar, a) .
mm of mercury (mm Hg)
liters per minute (I/min)
cubic decimeters/see (dm3/sec)
Newton (N)
kilogram (Kg)
second (see)
liter (I) .
degrees Celcius (oC)
Newton-meters (Nm)
kilowat (kw)
revolutions per minute (rpm)
Hertz (Hz) .
millileters/revolution
(ml/rev)
centistokes (cSt) .
meter per second (m/s)
inch (in).
Ibs/sq in (psig or psia) .
inches of mercury (in Hg)
U.S. gallons per minute (U.S. GPM) .
cubic feet per minute (cfm)
pound(f) or Ib(f) (force)
.
pound(m) or Ib(m)
(mass).
second (see)
gallon (U.S. gal) .
degrees Fahrenheit (0 F)
pounds(f)-inches
Ibs(f)-in
horsepower (HP) .
revolutions per minute (rpm)
cycles per second (cps) .
cubic inches per revolution (cipr).
Saybolt Universal Seconds (SUS)
feet per second (fps) .
NOTES:
*Pressure above atmospheric
1 Horsepower
Gallon = 1.2 U.S. Gallons
7.48 Gallons
=
1728 Cubic Inches
=
Approx.
14.5 PSI (Approx.l Atmos.)
33.8 Foot Water Column
42 Foot Oil Column
II
29.92 Hg.
VzPSI Decrease Each 1000 Ft. Altitude
APPROXIMATE
1
1
1
1
1
1
-
32)
1 Hz = 1 cps
·lml/rev = 0.061 cipr
cSt = (4.635)(SUS)tt
1 m/s = 3.28 fps
tGas
33,000 Ft. Lbs. per Minute
2545 BTU per Hour
746 Watts, or 0.746 Kilowatts
2.04161'Hg
27.71 "Water
Foot Column of Oil
1 Cubic Foot of Water Weighs 62.4 Pounds
=
(OF
1 Nm = 8.88 Ib(f)-in
1 kw = 1.34 HP
Foot Column of Water
=
1 Bar at Sea Level
1 U.S. gal = 3.791
°C = 5/9
550 Ft. Lbs. per Second
42.4 BTU per Minute
lPSI=
1 Liter = 0.2642 U.S. Gallons
1 Cubic Foot
1 in = 25.4 mm
1 bar = 14.5 psi
1 in Hg = 25.4 mm Hg
1 U.S. GPM = 3.79 I/min
1 dm3 /sec = 2.12 cfm
1 Ib(f) - 4.44N
1 Kg = 2.20 Ib(m)
***Liquid
4 Quarts; or 8 Pints
8.3356 Pounds
3.785 Liters
1 Imperial
Factor
MEASUREMENTS
231 Cu bic Inches
1 U.S. Ga lion
U.S. Unit
**Pressure below atmospheric
tt@38°C;
Factor is 4.667 @ 99°C
EQUIVALENT
Fluid Power Com-
Pint = 2 cups = 16 fluid ounces = 1 pound
Pint = 96 teaspoons = 32 tablespoons = 16 fluid ounces
Quart = 4 cups = 2 pints = 32 fluid ounces = 2 pounds
Quart = 192 teaspoons = 64 tablespoons = 32 fl. oz.
Gallon = 16 cups = 4 quarts = 8 pints
Gallon = 768 teaspoons = 256 tablespoons = 128 oz.
1 "Hg
=
=
= 0.433 PSI
= 0.390 PSI
0.491 PSI
1.132 Ft. Water
1 Barrel Oil = 42 Gallons
1 Micro-meter
25 Micro-meters
1 Millionth of a Meter (Micron)
= 1 Thousandth of a Meter
= 0.00004 Inch
=
= 0.001 Inch
MEASUREMENTS
1 Gallon = 231 cubic inches = 76,800 drops
1 Cup = 16 tablespoons = 48 teaspoons
1 Tablespoon = 3 teaspoons
2 Tablespoons = 1 fluid ounce
1 Fluid ounce (volume) = 600 drops (hydraulic
1 Cubic inch = 330 drops
oil)
TABLE 6-F. EQUIVALENT VALUES
To convert units appearing in Column 1 into equivalent values of units in Column 2, multiply by factor
Example: To convert 7 gallons into cubic inches, multiply 7 x 231 = 1617 cubic inches.
To convert units appearing in Column 2 into equivalent
values of units in Column 1, divide by factor
Example: To convert 25 horsepower
into BTU per minute, divide 25 by 0.02356 = 1061 BTU per minute.
.
Column 33.9
1
Column
Column
1per
144
745.7
0.01136
0.0005787
Column
Column
Feet
Column
of
Water
3Centimeters
2.Water
32per
Pounds
of
Water.
0.001341
Watts
.1.8+32
·Atmospheres
550
.231
0.1337
Seconds
2.036
2.307
88
0.25
0.01745
0.004329
Gallons
Watts
Cubic
Foot
Fahrenheit
2.54
0.04167
1000
Inches.
0.005952
Hou
Hours
0.02356
1728
0.2931
Cubic
rs
lbs.
.nds
.of
.
7000
16
Pounds
0.6818
Inches.
U.S.
1.133
Inches
0.001
0.3937
Gallons
Meters
0.5
0.0001894
0.3048
2000
42.44
8.3453
Pou
29.92
Radians
5280
Quarts
0.001818
Feet
453.5924
0.00004
0.2642
1.467
liters
0.0000303
00.8826
oCx
778.3
0.4335
7.48052
Weeks.
Watts
14.7
Centimeters
Ounces
Grains.
Grams.
.001286
Inches.
Miles
liters
0.0625
1.805
0.4912
0.03342
Pints
0.0002642
Pounds
Quarts
Feet
.of
of
Inches.
0.5555
Tons
(U.SJ
86,400
Water
0.06804
Micro-meter
Inches.
(Micron)
0.03613
Ounces
0.0295
(Fluid)
BTU
Horsepower
per
Minute.
.Second
(Statute)
Horsepower
.Sq.(MPH)
33,000
Foot
Square
lbs.
Inches
per
Minute
Horsepower
U.S.Galions
Miles
Inches
per
of
Hour{MPH)
Hour
Minute
Mercury
.Sq.
...In.)
Inches
Gallons
Days
per
Hour
Mercury
(U.S.
liquid
liquid)
In)
("Hg)
PSI
(lbs.
Sq.
Temperature
(oC)
(oF)
- 32
Feet
.(Bars)*.
PSI
PSI
Feet
(lbs.
(lbs.perSq.ln).
(lbs.
per
per
Second.
In)
Inches
Atmospheres
of
(Weight)
Mercury
.in)
("Hg)
InJ
(Bars)*.
Please read instructions
in Column
3,
in Column
3.
above
TABLE 6-G. PSI GAUGE PRESSURE CONVERTED TO METRIC PRESSURE UNITS
This table is calculated
PSI
Bars
on the basis of 1 bar = 14.5 PSI, or, 1 PSI = .069 bar
• 10
••.....0.69
50
3.45
100
6.90
250
17.2
500
34.5
750
51.7
1000
69.0
1500
103.4
2000
137.9
2500
172.4
3000
206.9
5000
344.8
TABLE 6-H. GPM OIL FLOW CONVERTED TO METRIC UNITS
This table
GPM
.5
Liters/min~18.95
is calculated
on the basis of 1 U.S. GPM = 3.79 liters per min. (liquid)
8
30.32
12
45.48
15
56.85
20
75.80
25
94.75
30
113.7
35
132.7
or, 1 liter per min. = 0.2638
40
151.6
50
189.5
75
284.3
GPM.
100
379.0
TABLE 6-1. SCFM AIR FLOW CONVERTED TO METRIC UNITS
This table
SCFM
~5
Dm3/sec~2.358
is calculated
on the basis of 1 SCFM = 0.4716
10
4.716
15
7.074
25
11.79
50
23.58
cubic decimeters
75
35.37
100
47.16
per second,
150
70.74
200
94.32
or 1 dm3/sec.
250
117.9
= 2.12 SCFM.
300
141.5
350
165.1