Formulas
Metric Conversions |
||
| America | Metric | Conversion Formula |
| Pounds per square inch (psig) | Kilograms per centimeter squared (kg/cm2) | psig x 0.0703 = kg/cm2 |
| Pounds per square inch (psig) |
Kilopascals (kPa) | psig x 6.895 = kPa |
| Pounds per square inch (psig) | Bar | psig x 0.069 = bar |
| Gallons per minute (GPM) | L/min. | GPM x 3.79 = L/min. |
| Gallons per minute (GPM) | Cubic centimeters per minute (cc) | GPM x 3785 = cc/min. |
| Degrees Fahrenheit (°F) | Degrees Celsius (°C) | 5/9(°F-32) = °C |
| Inches Mercury at 60°F | Millibar (mbar) | "HG x 33.8 = mbar |
| Inches (") | Millimeters (mm) | " x 25.4 = mm |
| Inch pounds (in•lbs) | Newton meters (N•m) | in•lbs x 0.113 = N•m |
| Foot pounds (ft•lbs) | Newton meters (N•m) | ft•lbs x 1.356 = N•m |
| Cv | Kv | Cv x 14.28 = Kv |
Cv Factor
"Cv" flow factor is the number of gallons of water that pass through a given orifice area in one minute at a pressure drop of one psig.
"Kv" flow factor is the number of liters of water that pass through a given orifice area in one minute at a pressure drop of one bar.
Flow Calculations
Basic Formula for System Designing
Flow Estimate
Q = 2.449 VD2
Where:
Q = gallons per minute
V = velocity, feet per second
D = inside diameter, inches
Pipe Diameter Estimate
Velocity Estimate
Pressure Loss Due to Friction
Hazen & Williams Formula
Where:
Q = gallons per minute,
fluid with specific gravity 1.0
C = velocity, feet per second
D = inside diameter, inches
Approximate Burst Pressure of Tubing or Pipe
BP = W x T
ID
Where:
BP = burst pressure, psig
W = wall thickness, inches
T = tensile strength, psi
ID = inside diameter, inches
For additional application assistance contact Entegris.
Fitting Pressure Drop Calculation
Le = K x ID
K = configuration constant
ID = fitting inside diameter, feet
Le = equivalent tubing length
K values (same size ends)
90° Elbow K = 30
45° Elbow and Sweep Elbow K = 16
Tee (flow through run) K = 20
Tee (flow through branch) K = 60
Fitting pressure drop calculator
Material Tensile Strength
FEP = 3000 @ 23°C (73°F)
PFA = 3600 @ 23°C (73°F), 1800 @ 250°C (482°F)
Tefzel® = 6500 @ 23°C (73°F), 3000 @ 93°C (200°F), 1300 @ 149°C (300°F)