Flowmeter Sizing

Gas Flowmeter Sizing     Click Here To Download A Printable Version
Variable area flowmeters suitable for liquid service have a capacity rating based on water at 70° Fahrenheit. Flowmeters suitable
for gas service have a capacity rating based on air at STP (70°F, 14.7 PSIA) conditions. The correction factors listed below are
used to calculate the flow capacity when using a liquid other than water or a gas other than air at STP conditions.


GAS CORRECTION FORMULA

Air Equivalent Flow Rate =   Customer Gas Flow Rate
X Gas Correction Factor

Step 1: Convert Customer Gas Flow Rate unit of measure to a standard unit of measure for air flow (SCFM or SCCM).

Step 2: Calculate Gas Correction Factor from given values.

Step 3: Calculate the product of the Air Equivalent Flow Rate from the Customer Gas Flow Rate and the Gas Correction Factor.

Step 4: Calculate the maximum or minimum flow rate for the customer’s conditions.

Step 1: Convert Customer Gas Flow Rate unit of measure to
a standardunit of measure for air flow

Customer Gas Flow Rate ________________
Converted Gas Flow Rate ________________ SCFM / SCCM

Gas Flow Rate Conversions
From To  SCFM   From To SCCM
SCFH Divide by 60   SCFM Multiply by 28,317
SCIM Divide by 1,728   SCFH Multiply by 472
SLPM Divide by 28.317   SCIM Multiply by 16.39
SM³/MIN Multiply by 35.31   SLPM Multiply by 1,000
SM³/HR Multiply by 0.5885   SLPH Multiply by 16.67
NM³/MIN Multiply by 37.99   SM³/MIN Multiply by 1,000,000
NM³/HR Multiply by 0.6331   SM³/HR Multiply by 16,667
SCCM Divide by 28,317   NM³/MIN Multiply by 1,075,785
KG/MIN Multiply by (29.39 ÷ SpGr)   NM³/HR Multiply by 17,929
KG/HR Multiply by (0.49  ÷ SpGr)   KG/MIN Multiply by (832,000 ÷ SpGr)
LBS/MIN Multiply by (13.33 ÷ SpGr)   KG/HR Multiply by (13,876 ÷ SpGr)
LBS/HR Multiply by(0.2222 ÷ SpGr)   LBS/MIN Multiply by (377,500 ÷ SpGr)
LBS/DAY Multiply by (0.00926 ÷ SpGr)   LBS/HR Multiply by (6,292 ÷ SpGr)
ACFM Multiply by [[(Operating PSIG+14.7)(530)] ÷ [(14.7)(Operating °F+460)]]

 

Step 2: Calculate Gas Correction Factor from given values

This information is required to size for conditions other than air at STP:
• Operating Temperature: _________°F
• Operating Back Pressure:_________ PSIG
• Specific Gravity of Gas: _________ @STP

Temperature Conversions
 
Gas Density Conversions
From To °Fahrenheit   From To Specific Gravity
°Centigrade (°C X 1.8) + 32   LBS/FT³ Divide by 0.075
°Kelvin (°K – 273.15)1.8 + 32   KG/M³ Divide by 1.2
°Rankine °R – 459.67   MolWt Divide by 29.0
      g/cm³ Divide by 0.0012

 

Pressure Conversions
From To PSIG   From To PSIG
foot Water Divide by 2.308   Pa (Pa÷101,300) X 14.7
Inch Water Divide by 27.73   PSIA Minus 14.7
mm Water Divide by 704   ATM (ATM X 14.7) – 14.7
inch Hg Divide by 2.036   Torr ((Torr÷760) X14.7) – 14.7
mm Hg Divide by 51.7   Bars ((Bars÷1.013) X14.7) – 14.7
kg/cm² Multiply by 14.228   Millibar ((Millibars÷1013) X 14.7) –14.7
kPa (kPa÷101.3) X 14.7      

Gas Correction Factor (GCF) formula:

GCF = _________________

Step 3: Determine the Air Equivalent Flow Rate.

Air Equivalent Flow Rate = Customer Gas Flow Rate x Gas Correction Factor
Air Equivalent Flow Rate = ____________________

Step 4: Calculate the maximum or minimum flow rate for the
customer’s conditions (Customer Gas Flow Rate Scale)


Customer Gas Flow Rate Scale = Catalog Flow Rate ÷ Gas Correction Factor
Customer Gas Flow Rate Scale = ______________________

 
Liquid Flowmeter Sizing     Click Here To Download A Printable Version
Variable area flowmeters suitable for liquid service have a capacity rating based on water at 70°Fahrenheit. Flowmeters suitable for gas service have a capacity rating based on air at STP (70°F, 14.7 PSIA) conditions. The correction factors listed below are used to calculate the flow capacity when using a liquid other than water or a gas other than air at STP conditions.

LIQUID CORRECTION FORMULA

Water Equivalent Flow Rate =  Customer Liquid Flow Rate
X Liquid Correction Factor

Step 1: Convert Customer Liquid Flow Rate unit of measure to a standard unit of measure for water flow (GPM or CC/MIN).

Step 2: Calculate Liquid Specific GravityCorrection Factor from given values.

Step 3: Determine the Water Equivalent Flow Rate from the product of the Customer Liquid Flow Rate and the Liquid Correction Factor.

Step 4: Calculate the maximum or minimum flow rate for the customer’s conditions.

Step 1: Convert Customer Liquid Flow Rate unit of measure
to a standard unit of measure for water flow.

Customer Liquid Flow Rate ________________
Converted Gas Flow Rate _________________GPM / CC/MIN

Liquid Flow Rate Conversions
From To  GPM   From To CC/MIN
GPH Divide by 60   GPM Multiply by 3,785
CC/MIN Divide by 3,785   GPH Multiply by 63.08
CC/HR Divide by 227,100   CC/HR Divide by 60
LPM Multiply by 3.785   LPM Multiply by 1,000
LPH Multiply by 227.1   LPH Multiply by 16.67
M³/MIN Multiply by 264.2   M³/MIN Multiply by 1,000,000
M³/HR Multiply by 4.402   M³/HR Multiply by 16,667
PINTS/MIN Divide by 8   PINTS/MIN Multiply by 473.1
FT³/MIN Multiply by 7.48   FT³/MIN Multiply by 28,320
FT³/HR Divide by 8.021   FT³/HR Multiply by 472
KG/MIN Multiply by (0.264 ÷ SpGr)   KG/MIN Multiply by (1,000 ÷ SpGr)
KG/HR Divide by (227 X SpGr)   KG/HR Multiply by (16.67 ÷ SpGr)
LBS/MIN Divide by (8.347 X SpGr)   LBS/MIN Multiply by (453.6 ÷ SpGr)
LBS/HR Divide by (500.8 X SpGr)   LBS/HR Multiply by (7.56 ÷ Spgr)
GMS/MIN Divide by (3,785 X SpGr)   GMS/MIN Divide by SpGr
GMS/HR Divide by (227,000 X SpGr)   GMS/HR Multiply by 3.785 Divide by (60 X SpGr)

Step 2: Calculate Liquid Correction Factor from given values

This information is required to size for liquids other than water:

• Specific Gravity of Liquid:____________ @ Operating Conditions
• Liquid Temperature:__________°F @ Operating Conditions
• Liquid Viscosity: _________cps @Operating Conditions
• Specific Gravity of the Float to be used: ___________

Float Specific Gravity
 
Liquid Density Conversions
Teflon 2.20 316 SS 8.04   From To Specific Gravity
Glass 2.53 Hastelloy C 8.94   LBS/FT³ Divide by 62.4
Sapphire 3.99 Carboloy 15.00   KG/M³ Divide by 1,000
Titanium 4.50 Tantalum 16.60   API [141.5 ÷ (131.5+API)]
316L SS 8.03       g/cm³ = SpGr

Liquid Specific Gravity Correction Factor (LSGCF) formula:



3. Determine the Water Equivalent Flow Rate

Water Equivalent Flow Rate = Customer’s Liquid Flow Rate ÷ LSGCF Water Equivalent Flow Rate = ______________________

4. Calculate the maximum or minimum flow rate for the customer’s conditions. (Customer Liquid Flow Rate Scale)

Customer Liquid Flow Rate Scale = Catalog Flow Rate ÷ LSGCF @ 70° F
Customer Liquid Flow Rate Scale = ____________________